1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  Simplified MAC Kernel (smack) security module
4  *
5  *  This file contains the smack hook function implementations.
6  *
7  *  Authors:
8  *	Casey Schaufler <casey@schaufler-ca.com>
9  *	Jarkko Sakkinen <jarkko.sakkinen@intel.com>
10  *
11  *  Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
12  *  Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
13  *                Paul Moore <paul@paul-moore.com>
14  *  Copyright (C) 2010 Nokia Corporation
15  *  Copyright (C) 2011 Intel Corporation.
16  */
17 
18 #include <linux/xattr.h>
19 #include <linux/pagemap.h>
20 #include <linux/mount.h>
21 #include <linux/stat.h>
22 #include <linux/kd.h>
23 #include <asm/ioctls.h>
24 #include <linux/ip.h>
25 #include <linux/tcp.h>
26 #include <linux/udp.h>
27 #include <linux/dccp.h>
28 #include <linux/icmpv6.h>
29 #include <linux/slab.h>
30 #include <linux/mutex.h>
31 #include <net/cipso_ipv4.h>
32 #include <net/ip.h>
33 #include <net/ipv6.h>
34 #include <linux/audit.h>
35 #include <linux/magic.h>
36 #include <linux/dcache.h>
37 #include <linux/personality.h>
38 #include <linux/msg.h>
39 #include <linux/shm.h>
40 #include <linux/binfmts.h>
41 #include <linux/parser.h>
42 #include <linux/fs_context.h>
43 #include <linux/fs_parser.h>
44 #include <linux/watch_queue.h>
45 #include "smack.h"
46 
47 #define TRANS_TRUE	"TRUE"
48 #define TRANS_TRUE_SIZE	4
49 
50 #define SMK_CONNECTING	0
51 #define SMK_RECEIVING	1
52 #define SMK_SENDING	2
53 
54 static DEFINE_MUTEX(smack_ipv6_lock);
55 static LIST_HEAD(smk_ipv6_port_list);
56 struct kmem_cache *smack_rule_cache;
57 int smack_enabled;
58 
59 #define A(s) {"smack"#s, sizeof("smack"#s) - 1, Opt_##s}
60 static struct {
61 	const char *name;
62 	int len;
63 	int opt;
64 } smk_mount_opts[] = {
65 	{"smackfsdef", sizeof("smackfsdef") - 1, Opt_fsdefault},
66 	A(fsdefault), A(fsfloor), A(fshat), A(fsroot), A(fstransmute)
67 };
68 #undef A
69 
match_opt_prefix(char *s, int l, char **arg)70 static int match_opt_prefix(char *s, int l, char **arg)
71 {
72 	int i;
73 
74 	for (i = 0; i < ARRAY_SIZE(smk_mount_opts); i++) {
75 		size_t len = smk_mount_opts[i].len;
76 		if (len > l || memcmp(s, smk_mount_opts[i].name, len))
77 			continue;
78 		if (len == l || s[len] != '=')
79 			continue;
80 		*arg = s + len + 1;
81 		return smk_mount_opts[i].opt;
82 	}
83 	return Opt_error;
84 }
85 
86 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
87 static char *smk_bu_mess[] = {
88 	"Bringup Error",	/* Unused */
89 	"Bringup",		/* SMACK_BRINGUP_ALLOW */
90 	"Unconfined Subject",	/* SMACK_UNCONFINED_SUBJECT */
91 	"Unconfined Object",	/* SMACK_UNCONFINED_OBJECT */
92 };
93 
smk_bu_mode(int mode, char *s)94 static void smk_bu_mode(int mode, char *s)
95 {
96 	int i = 0;
97 
98 	if (mode & MAY_READ)
99 		s[i++] = 'r';
100 	if (mode & MAY_WRITE)
101 		s[i++] = 'w';
102 	if (mode & MAY_EXEC)
103 		s[i++] = 'x';
104 	if (mode & MAY_APPEND)
105 		s[i++] = 'a';
106 	if (mode & MAY_TRANSMUTE)
107 		s[i++] = 't';
108 	if (mode & MAY_LOCK)
109 		s[i++] = 'l';
110 	if (i == 0)
111 		s[i++] = '-';
112 	s[i] = '\0';
113 }
114 #endif
115 
116 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
smk_bu_note(char *note, struct smack_known *sskp, struct smack_known *oskp, int mode, int rc)117 static int smk_bu_note(char *note, struct smack_known *sskp,
118 		       struct smack_known *oskp, int mode, int rc)
119 {
120 	char acc[SMK_NUM_ACCESS_TYPE + 1];
121 
122 	if (rc <= 0)
123 		return rc;
124 	if (rc > SMACK_UNCONFINED_OBJECT)
125 		rc = 0;
126 
127 	smk_bu_mode(mode, acc);
128 	pr_info("Smack %s: (%s %s %s) %s\n", smk_bu_mess[rc],
129 		sskp->smk_known, oskp->smk_known, acc, note);
130 	return 0;
131 }
132 #else
133 #define smk_bu_note(note, sskp, oskp, mode, RC) (RC)
134 #endif
135 
136 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
smk_bu_current(char *note, struct smack_known *oskp, int mode, int rc)137 static int smk_bu_current(char *note, struct smack_known *oskp,
138 			  int mode, int rc)
139 {
140 	struct task_smack *tsp = smack_cred(current_cred());
141 	char acc[SMK_NUM_ACCESS_TYPE + 1];
142 
143 	if (rc <= 0)
144 		return rc;
145 	if (rc > SMACK_UNCONFINED_OBJECT)
146 		rc = 0;
147 
148 	smk_bu_mode(mode, acc);
149 	pr_info("Smack %s: (%s %s %s) %s %s\n", smk_bu_mess[rc],
150 		tsp->smk_task->smk_known, oskp->smk_known,
151 		acc, current->comm, note);
152 	return 0;
153 }
154 #else
155 #define smk_bu_current(note, oskp, mode, RC) (RC)
156 #endif
157 
158 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
smk_bu_task(struct task_struct *otp, int mode, int rc)159 static int smk_bu_task(struct task_struct *otp, int mode, int rc)
160 {
161 	struct task_smack *tsp = smack_cred(current_cred());
162 	struct smack_known *smk_task = smk_of_task_struct(otp);
163 	char acc[SMK_NUM_ACCESS_TYPE + 1];
164 
165 	if (rc <= 0)
166 		return rc;
167 	if (rc > SMACK_UNCONFINED_OBJECT)
168 		rc = 0;
169 
170 	smk_bu_mode(mode, acc);
171 	pr_info("Smack %s: (%s %s %s) %s to %s\n", smk_bu_mess[rc],
172 		tsp->smk_task->smk_known, smk_task->smk_known, acc,
173 		current->comm, otp->comm);
174 	return 0;
175 }
176 #else
177 #define smk_bu_task(otp, mode, RC) (RC)
178 #endif
179 
180 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
smk_bu_inode(struct inode *inode, int mode, int rc)181 static int smk_bu_inode(struct inode *inode, int mode, int rc)
182 {
183 	struct task_smack *tsp = smack_cred(current_cred());
184 	struct inode_smack *isp = smack_inode(inode);
185 	char acc[SMK_NUM_ACCESS_TYPE + 1];
186 
187 	if (isp->smk_flags & SMK_INODE_IMPURE)
188 		pr_info("Smack Unconfined Corruption: inode=(%s %ld) %s\n",
189 			inode->i_sb->s_id, inode->i_ino, current->comm);
190 
191 	if (rc <= 0)
192 		return rc;
193 	if (rc > SMACK_UNCONFINED_OBJECT)
194 		rc = 0;
195 	if (rc == SMACK_UNCONFINED_SUBJECT &&
196 	    (mode & (MAY_WRITE | MAY_APPEND)))
197 		isp->smk_flags |= SMK_INODE_IMPURE;
198 
199 	smk_bu_mode(mode, acc);
200 
201 	pr_info("Smack %s: (%s %s %s) inode=(%s %ld) %s\n", smk_bu_mess[rc],
202 		tsp->smk_task->smk_known, isp->smk_inode->smk_known, acc,
203 		inode->i_sb->s_id, inode->i_ino, current->comm);
204 	return 0;
205 }
206 #else
207 #define smk_bu_inode(inode, mode, RC) (RC)
208 #endif
209 
210 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
smk_bu_file(struct file *file, int mode, int rc)211 static int smk_bu_file(struct file *file, int mode, int rc)
212 {
213 	struct task_smack *tsp = smack_cred(current_cred());
214 	struct smack_known *sskp = tsp->smk_task;
215 	struct inode *inode = file_inode(file);
216 	struct inode_smack *isp = smack_inode(inode);
217 	char acc[SMK_NUM_ACCESS_TYPE + 1];
218 
219 	if (isp->smk_flags & SMK_INODE_IMPURE)
220 		pr_info("Smack Unconfined Corruption: inode=(%s %ld) %s\n",
221 			inode->i_sb->s_id, inode->i_ino, current->comm);
222 
223 	if (rc <= 0)
224 		return rc;
225 	if (rc > SMACK_UNCONFINED_OBJECT)
226 		rc = 0;
227 
228 	smk_bu_mode(mode, acc);
229 	pr_info("Smack %s: (%s %s %s) file=(%s %ld %pD) %s\n", smk_bu_mess[rc],
230 		sskp->smk_known, smk_of_inode(inode)->smk_known, acc,
231 		inode->i_sb->s_id, inode->i_ino, file,
232 		current->comm);
233 	return 0;
234 }
235 #else
236 #define smk_bu_file(file, mode, RC) (RC)
237 #endif
238 
239 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
smk_bu_credfile(const struct cred *cred, struct file *file, int mode, int rc)240 static int smk_bu_credfile(const struct cred *cred, struct file *file,
241 				int mode, int rc)
242 {
243 	struct task_smack *tsp = smack_cred(cred);
244 	struct smack_known *sskp = tsp->smk_task;
245 	struct inode *inode = file_inode(file);
246 	struct inode_smack *isp = smack_inode(inode);
247 	char acc[SMK_NUM_ACCESS_TYPE + 1];
248 
249 	if (isp->smk_flags & SMK_INODE_IMPURE)
250 		pr_info("Smack Unconfined Corruption: inode=(%s %ld) %s\n",
251 			inode->i_sb->s_id, inode->i_ino, current->comm);
252 
253 	if (rc <= 0)
254 		return rc;
255 	if (rc > SMACK_UNCONFINED_OBJECT)
256 		rc = 0;
257 
258 	smk_bu_mode(mode, acc);
259 	pr_info("Smack %s: (%s %s %s) file=(%s %ld %pD) %s\n", smk_bu_mess[rc],
260 		sskp->smk_known, smk_of_inode(inode)->smk_known, acc,
261 		inode->i_sb->s_id, inode->i_ino, file,
262 		current->comm);
263 	return 0;
264 }
265 #else
266 #define smk_bu_credfile(cred, file, mode, RC) (RC)
267 #endif
268 
269 /**
270  * smk_fetch - Fetch the smack label from a file.
271  * @name: type of the label (attribute)
272  * @ip: a pointer to the inode
273  * @dp: a pointer to the dentry
274  *
275  * Returns a pointer to the master list entry for the Smack label,
276  * NULL if there was no label to fetch, or an error code.
277  */
smk_fetch(const char *name, struct inode *ip, struct dentry *dp)278 static struct smack_known *smk_fetch(const char *name, struct inode *ip,
279 					struct dentry *dp)
280 {
281 	int rc;
282 	char *buffer;
283 	struct smack_known *skp = NULL;
284 
285 	if (!(ip->i_opflags & IOP_XATTR))
286 		return ERR_PTR(-EOPNOTSUPP);
287 
288 	buffer = kzalloc(SMK_LONGLABEL, GFP_NOFS);
289 	if (buffer == NULL)
290 		return ERR_PTR(-ENOMEM);
291 
292 	rc = __vfs_getxattr(dp, ip, name, buffer, SMK_LONGLABEL);
293 	if (rc < 0)
294 		skp = ERR_PTR(rc);
295 	else if (rc == 0)
296 		skp = NULL;
297 	else
298 		skp = smk_import_entry(buffer, rc);
299 
300 	kfree(buffer);
301 
302 	return skp;
303 }
304 
305 /**
306  * init_inode_smack - initialize an inode security blob
307  * @inode: inode to extract the info from
308  * @skp: a pointer to the Smack label entry to use in the blob
309  *
310  */
init_inode_smack(struct inode *inode, struct smack_known *skp)311 static void init_inode_smack(struct inode *inode, struct smack_known *skp)
312 {
313 	struct inode_smack *isp = smack_inode(inode);
314 
315 	isp->smk_inode = skp;
316 	isp->smk_flags = 0;
317 }
318 
319 /**
320  * init_task_smack - initialize a task security blob
321  * @tsp: blob to initialize
322  * @task: a pointer to the Smack label for the running task
323  * @forked: a pointer to the Smack label for the forked task
324  *
325  */
init_task_smack(struct task_smack *tsp, struct smack_known *task, struct smack_known *forked)326 static void init_task_smack(struct task_smack *tsp, struct smack_known *task,
327 					struct smack_known *forked)
328 {
329 	tsp->smk_task = task;
330 	tsp->smk_forked = forked;
331 	INIT_LIST_HEAD(&tsp->smk_rules);
332 	INIT_LIST_HEAD(&tsp->smk_relabel);
333 	mutex_init(&tsp->smk_rules_lock);
334 }
335 
336 /**
337  * smk_copy_rules - copy a rule set
338  * @nhead: new rules header pointer
339  * @ohead: old rules header pointer
340  * @gfp: type of the memory for the allocation
341  *
342  * Returns 0 on success, -ENOMEM on error
343  */
smk_copy_rules(struct list_head *nhead, struct list_head *ohead, gfp_t gfp)344 static int smk_copy_rules(struct list_head *nhead, struct list_head *ohead,
345 				gfp_t gfp)
346 {
347 	struct smack_rule *nrp;
348 	struct smack_rule *orp;
349 	int rc = 0;
350 
351 	list_for_each_entry_rcu(orp, ohead, list) {
352 		nrp = kmem_cache_zalloc(smack_rule_cache, gfp);
353 		if (nrp == NULL) {
354 			rc = -ENOMEM;
355 			break;
356 		}
357 		*nrp = *orp;
358 		list_add_rcu(&nrp->list, nhead);
359 	}
360 	return rc;
361 }
362 
363 /**
364  * smk_copy_relabel - copy smk_relabel labels list
365  * @nhead: new rules header pointer
366  * @ohead: old rules header pointer
367  * @gfp: type of the memory for the allocation
368  *
369  * Returns 0 on success, -ENOMEM on error
370  */
smk_copy_relabel(struct list_head *nhead, struct list_head *ohead, gfp_t gfp)371 static int smk_copy_relabel(struct list_head *nhead, struct list_head *ohead,
372 				gfp_t gfp)
373 {
374 	struct smack_known_list_elem *nklep;
375 	struct smack_known_list_elem *oklep;
376 
377 	list_for_each_entry(oklep, ohead, list) {
378 		nklep = kzalloc(sizeof(struct smack_known_list_elem), gfp);
379 		if (nklep == NULL) {
380 			smk_destroy_label_list(nhead);
381 			return -ENOMEM;
382 		}
383 		nklep->smk_label = oklep->smk_label;
384 		list_add(&nklep->list, nhead);
385 	}
386 
387 	return 0;
388 }
389 
390 /**
391  * smk_ptrace_mode - helper function for converting PTRACE_MODE_* into MAY_*
392  * @mode - input mode in form of PTRACE_MODE_*
393  *
394  * Returns a converted MAY_* mode usable by smack rules
395  */
smk_ptrace_mode(unsigned int mode)396 static inline unsigned int smk_ptrace_mode(unsigned int mode)
397 {
398 	if (mode & PTRACE_MODE_ATTACH)
399 		return MAY_READWRITE;
400 	if (mode & PTRACE_MODE_READ)
401 		return MAY_READ;
402 
403 	return 0;
404 }
405 
406 /**
407  * smk_ptrace_rule_check - helper for ptrace access
408  * @tracer: tracer process
409  * @tracee_known: label entry of the process that's about to be traced
410  * @mode: ptrace attachment mode (PTRACE_MODE_*)
411  * @func: name of the function that called us, used for audit
412  *
413  * Returns 0 on access granted, -error on error
414  */
smk_ptrace_rule_check(struct task_struct *tracer, struct smack_known *tracee_known, unsigned int mode, const char *func)415 static int smk_ptrace_rule_check(struct task_struct *tracer,
416 				 struct smack_known *tracee_known,
417 				 unsigned int mode, const char *func)
418 {
419 	int rc;
420 	struct smk_audit_info ad, *saip = NULL;
421 	struct task_smack *tsp;
422 	struct smack_known *tracer_known;
423 	const struct cred *tracercred;
424 
425 	if ((mode & PTRACE_MODE_NOAUDIT) == 0) {
426 		smk_ad_init(&ad, func, LSM_AUDIT_DATA_TASK);
427 		smk_ad_setfield_u_tsk(&ad, tracer);
428 		saip = &ad;
429 	}
430 
431 	rcu_read_lock();
432 	tracercred = __task_cred(tracer);
433 	tsp = smack_cred(tracercred);
434 	tracer_known = smk_of_task(tsp);
435 
436 	if ((mode & PTRACE_MODE_ATTACH) &&
437 	    (smack_ptrace_rule == SMACK_PTRACE_EXACT ||
438 	     smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)) {
439 		if (tracer_known->smk_known == tracee_known->smk_known)
440 			rc = 0;
441 		else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)
442 			rc = -EACCES;
443 		else if (smack_privileged_cred(CAP_SYS_PTRACE, tracercred))
444 			rc = 0;
445 		else
446 			rc = -EACCES;
447 
448 		if (saip)
449 			smack_log(tracer_known->smk_known,
450 				  tracee_known->smk_known,
451 				  0, rc, saip);
452 
453 		rcu_read_unlock();
454 		return rc;
455 	}
456 
457 	/* In case of rule==SMACK_PTRACE_DEFAULT or mode==PTRACE_MODE_READ */
458 	rc = smk_tskacc(tsp, tracee_known, smk_ptrace_mode(mode), saip);
459 
460 	rcu_read_unlock();
461 	return rc;
462 }
463 
464 /*
465  * LSM hooks.
466  * We he, that is fun!
467  */
468 
469 /**
470  * smack_ptrace_access_check - Smack approval on PTRACE_ATTACH
471  * @ctp: child task pointer
472  * @mode: ptrace attachment mode (PTRACE_MODE_*)
473  *
474  * Returns 0 if access is OK, an error code otherwise
475  *
476  * Do the capability checks.
477  */
smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)478 static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
479 {
480 	struct smack_known *skp;
481 
482 	skp = smk_of_task_struct(ctp);
483 
484 	return smk_ptrace_rule_check(current, skp, mode, __func__);
485 }
486 
487 /**
488  * smack_ptrace_traceme - Smack approval on PTRACE_TRACEME
489  * @ptp: parent task pointer
490  *
491  * Returns 0 if access is OK, an error code otherwise
492  *
493  * Do the capability checks, and require PTRACE_MODE_ATTACH.
494  */
smack_ptrace_traceme(struct task_struct *ptp)495 static int smack_ptrace_traceme(struct task_struct *ptp)
496 {
497 	int rc;
498 	struct smack_known *skp;
499 
500 	skp = smk_of_task(smack_cred(current_cred()));
501 
502 	rc = smk_ptrace_rule_check(ptp, skp, PTRACE_MODE_ATTACH, __func__);
503 	return rc;
504 }
505 
506 /**
507  * smack_syslog - Smack approval on syslog
508  * @typefrom_file: unused
509  *
510  * Returns 0 on success, error code otherwise.
511  */
smack_syslog(int typefrom_file)512 static int smack_syslog(int typefrom_file)
513 {
514 	int rc = 0;
515 	struct smack_known *skp = smk_of_current();
516 
517 	if (smack_privileged(CAP_MAC_OVERRIDE))
518 		return 0;
519 
520 	if (smack_syslog_label != NULL && smack_syslog_label != skp)
521 		rc = -EACCES;
522 
523 	return rc;
524 }
525 
526 /*
527  * Superblock Hooks.
528  */
529 
530 /**
531  * smack_sb_alloc_security - allocate a superblock blob
532  * @sb: the superblock getting the blob
533  *
534  * Returns 0 on success or -ENOMEM on error.
535  */
smack_sb_alloc_security(struct super_block *sb)536 static int smack_sb_alloc_security(struct super_block *sb)
537 {
538 	struct superblock_smack *sbsp;
539 
540 	sbsp = kzalloc(sizeof(struct superblock_smack), GFP_KERNEL);
541 
542 	if (sbsp == NULL)
543 		return -ENOMEM;
544 
545 	sbsp->smk_root = &smack_known_floor;
546 	sbsp->smk_default = &smack_known_floor;
547 	sbsp->smk_floor = &smack_known_floor;
548 	sbsp->smk_hat = &smack_known_hat;
549 	/*
550 	 * SMK_SB_INITIALIZED will be zero from kzalloc.
551 	 */
552 	sb->s_security = sbsp;
553 
554 	return 0;
555 }
556 
557 /**
558  * smack_sb_free_security - free a superblock blob
559  * @sb: the superblock getting the blob
560  *
561  */
smack_sb_free_security(struct super_block *sb)562 static void smack_sb_free_security(struct super_block *sb)
563 {
564 	kfree(sb->s_security);
565 	sb->s_security = NULL;
566 }
567 
568 struct smack_mnt_opts {
569 	const char *fsdefault, *fsfloor, *fshat, *fsroot, *fstransmute;
570 };
571 
smack_free_mnt_opts(void *mnt_opts)572 static void smack_free_mnt_opts(void *mnt_opts)
573 {
574 	struct smack_mnt_opts *opts = mnt_opts;
575 	kfree(opts->fsdefault);
576 	kfree(opts->fsfloor);
577 	kfree(opts->fshat);
578 	kfree(opts->fsroot);
579 	kfree(opts->fstransmute);
580 	kfree(opts);
581 }
582 
smack_add_opt(int token, const char *s, void **mnt_opts)583 static int smack_add_opt(int token, const char *s, void **mnt_opts)
584 {
585 	struct smack_mnt_opts *opts = *mnt_opts;
586 
587 	if (!opts) {
588 		opts = kzalloc(sizeof(struct smack_mnt_opts), GFP_KERNEL);
589 		if (!opts)
590 			return -ENOMEM;
591 		*mnt_opts = opts;
592 	}
593 	if (!s)
594 		return -ENOMEM;
595 
596 	switch (token) {
597 	case Opt_fsdefault:
598 		if (opts->fsdefault)
599 			goto out_opt_err;
600 		opts->fsdefault = s;
601 		break;
602 	case Opt_fsfloor:
603 		if (opts->fsfloor)
604 			goto out_opt_err;
605 		opts->fsfloor = s;
606 		break;
607 	case Opt_fshat:
608 		if (opts->fshat)
609 			goto out_opt_err;
610 		opts->fshat = s;
611 		break;
612 	case Opt_fsroot:
613 		if (opts->fsroot)
614 			goto out_opt_err;
615 		opts->fsroot = s;
616 		break;
617 	case Opt_fstransmute:
618 		if (opts->fstransmute)
619 			goto out_opt_err;
620 		opts->fstransmute = s;
621 		break;
622 	}
623 	return 0;
624 
625 out_opt_err:
626 	pr_warn("Smack: duplicate mount options\n");
627 	return -EINVAL;
628 }
629 
630 /**
631  * smack_fs_context_dup - Duplicate the security data on fs_context duplication
632  * @fc: The new filesystem context.
633  * @src_fc: The source filesystem context being duplicated.
634  *
635  * Returns 0 on success or -ENOMEM on error.
636  */
smack_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc)637 static int smack_fs_context_dup(struct fs_context *fc,
638 				struct fs_context *src_fc)
639 {
640 	struct smack_mnt_opts *dst, *src = src_fc->security;
641 
642 	if (!src)
643 		return 0;
644 
645 	fc->security = kzalloc(sizeof(struct smack_mnt_opts), GFP_KERNEL);
646 	if (!fc->security)
647 		return -ENOMEM;
648 	dst = fc->security;
649 
650 	if (src->fsdefault) {
651 		dst->fsdefault = kstrdup(src->fsdefault, GFP_KERNEL);
652 		if (!dst->fsdefault)
653 			return -ENOMEM;
654 	}
655 	if (src->fsfloor) {
656 		dst->fsfloor = kstrdup(src->fsfloor, GFP_KERNEL);
657 		if (!dst->fsfloor)
658 			return -ENOMEM;
659 	}
660 	if (src->fshat) {
661 		dst->fshat = kstrdup(src->fshat, GFP_KERNEL);
662 		if (!dst->fshat)
663 			return -ENOMEM;
664 	}
665 	if (src->fsroot) {
666 		dst->fsroot = kstrdup(src->fsroot, GFP_KERNEL);
667 		if (!dst->fsroot)
668 			return -ENOMEM;
669 	}
670 	if (src->fstransmute) {
671 		dst->fstransmute = kstrdup(src->fstransmute, GFP_KERNEL);
672 		if (!dst->fstransmute)
673 			return -ENOMEM;
674 	}
675 	return 0;
676 }
677 
678 static const struct fs_parameter_spec smack_fs_parameters[] = {
679 	fsparam_string("smackfsdef",		Opt_fsdefault),
680 	fsparam_string("smackfsdefault",	Opt_fsdefault),
681 	fsparam_string("smackfsfloor",		Opt_fsfloor),
682 	fsparam_string("smackfshat",		Opt_fshat),
683 	fsparam_string("smackfsroot",		Opt_fsroot),
684 	fsparam_string("smackfstransmute",	Opt_fstransmute),
685 	{}
686 };
687 
688 /**
689  * smack_fs_context_parse_param - Parse a single mount parameter
690  * @fc: The new filesystem context being constructed.
691  * @param: The parameter.
692  *
693  * Returns 0 on success, -ENOPARAM to pass the parameter on or anything else on
694  * error.
695  */
smack_fs_context_parse_param(struct fs_context *fc, struct fs_parameter *param)696 static int smack_fs_context_parse_param(struct fs_context *fc,
697 					struct fs_parameter *param)
698 {
699 	struct fs_parse_result result;
700 	int opt, rc;
701 
702 	opt = fs_parse(fc, smack_fs_parameters, param, &result);
703 	if (opt < 0)
704 		return opt;
705 
706 	rc = smack_add_opt(opt, param->string, &fc->security);
707 	if (!rc)
708 		param->string = NULL;
709 	return rc;
710 }
711 
smack_sb_eat_lsm_opts(char *options, void **mnt_opts)712 static int smack_sb_eat_lsm_opts(char *options, void **mnt_opts)
713 {
714 	char *from = options, *to = options;
715 	bool first = true;
716 
717 	while (1) {
718 		char *next = strchr(from, ',');
719 		int token, len, rc;
720 		char *arg = NULL;
721 
722 		if (next)
723 			len = next - from;
724 		else
725 			len = strlen(from);
726 
727 		token = match_opt_prefix(from, len, &arg);
728 		if (token != Opt_error) {
729 			arg = kmemdup_nul(arg, from + len - arg, GFP_KERNEL);
730 			rc = smack_add_opt(token, arg, mnt_opts);
731 			if (unlikely(rc)) {
732 				kfree(arg);
733 				if (*mnt_opts)
734 					smack_free_mnt_opts(*mnt_opts);
735 				*mnt_opts = NULL;
736 				return rc;
737 			}
738 		} else {
739 			if (!first) {	// copy with preceding comma
740 				from--;
741 				len++;
742 			}
743 			if (to != from)
744 				memmove(to, from, len);
745 			to += len;
746 			first = false;
747 		}
748 		if (!from[len])
749 			break;
750 		from += len + 1;
751 	}
752 	*to = '\0';
753 	return 0;
754 }
755 
756 /**
757  * smack_set_mnt_opts - set Smack specific mount options
758  * @sb: the file system superblock
759  * @mnt_opts: Smack mount options
760  * @kern_flags: mount option from kernel space or user space
761  * @set_kern_flags: where to store converted mount opts
762  *
763  * Returns 0 on success, an error code on failure
764  *
765  * Allow filesystems with binary mount data to explicitly set Smack mount
766  * labels.
767  */
smack_set_mnt_opts(struct super_block *sb, void *mnt_opts, unsigned long kern_flags, unsigned long *set_kern_flags)768 static int smack_set_mnt_opts(struct super_block *sb,
769 		void *mnt_opts,
770 		unsigned long kern_flags,
771 		unsigned long *set_kern_flags)
772 {
773 	struct dentry *root = sb->s_root;
774 	struct inode *inode = d_backing_inode(root);
775 	struct superblock_smack *sp = sb->s_security;
776 	struct inode_smack *isp;
777 	struct smack_known *skp;
778 	struct smack_mnt_opts *opts = mnt_opts;
779 	bool transmute = false;
780 
781 	if (sp->smk_flags & SMK_SB_INITIALIZED)
782 		return 0;
783 
784 	if (inode->i_security == NULL) {
785 		int rc = lsm_inode_alloc(inode);
786 
787 		if (rc)
788 			return rc;
789 	}
790 
791 	if (!smack_privileged(CAP_MAC_ADMIN)) {
792 		/*
793 		 * Unprivileged mounts don't get to specify Smack values.
794 		 */
795 		if (opts)
796 			return -EPERM;
797 		/*
798 		 * Unprivileged mounts get root and default from the caller.
799 		 */
800 		skp = smk_of_current();
801 		sp->smk_root = skp;
802 		sp->smk_default = skp;
803 		/*
804 		 * For a handful of fs types with no user-controlled
805 		 * backing store it's okay to trust security labels
806 		 * in the filesystem. The rest are untrusted.
807 		 */
808 		if (sb->s_user_ns != &init_user_ns &&
809 		    sb->s_magic != SYSFS_MAGIC && sb->s_magic != TMPFS_MAGIC &&
810 		    sb->s_magic != RAMFS_MAGIC) {
811 			transmute = true;
812 			sp->smk_flags |= SMK_SB_UNTRUSTED;
813 		}
814 	}
815 
816 	sp->smk_flags |= SMK_SB_INITIALIZED;
817 
818 	if (opts) {
819 		if (opts->fsdefault) {
820 			skp = smk_import_entry(opts->fsdefault, 0);
821 			if (IS_ERR(skp))
822 				return PTR_ERR(skp);
823 			sp->smk_default = skp;
824 		}
825 		if (opts->fsfloor) {
826 			skp = smk_import_entry(opts->fsfloor, 0);
827 			if (IS_ERR(skp))
828 				return PTR_ERR(skp);
829 			sp->smk_floor = skp;
830 		}
831 		if (opts->fshat) {
832 			skp = smk_import_entry(opts->fshat, 0);
833 			if (IS_ERR(skp))
834 				return PTR_ERR(skp);
835 			sp->smk_hat = skp;
836 		}
837 		if (opts->fsroot) {
838 			skp = smk_import_entry(opts->fsroot, 0);
839 			if (IS_ERR(skp))
840 				return PTR_ERR(skp);
841 			sp->smk_root = skp;
842 		}
843 		if (opts->fstransmute) {
844 			skp = smk_import_entry(opts->fstransmute, 0);
845 			if (IS_ERR(skp))
846 				return PTR_ERR(skp);
847 			sp->smk_root = skp;
848 			transmute = true;
849 		}
850 	}
851 
852 	/*
853 	 * Initialize the root inode.
854 	 */
855 	init_inode_smack(inode, sp->smk_root);
856 
857 	if (transmute) {
858 		isp = smack_inode(inode);
859 		isp->smk_flags |= SMK_INODE_TRANSMUTE;
860 	}
861 
862 	return 0;
863 }
864 
865 /**
866  * smack_sb_statfs - Smack check on statfs
867  * @dentry: identifies the file system in question
868  *
869  * Returns 0 if current can read the floor of the filesystem,
870  * and error code otherwise
871  */
smack_sb_statfs(struct dentry *dentry)872 static int smack_sb_statfs(struct dentry *dentry)
873 {
874 	struct superblock_smack *sbp = dentry->d_sb->s_security;
875 	int rc;
876 	struct smk_audit_info ad;
877 
878 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
879 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
880 
881 	rc = smk_curacc(sbp->smk_floor, MAY_READ, &ad);
882 	rc = smk_bu_current("statfs", sbp->smk_floor, MAY_READ, rc);
883 	return rc;
884 }
885 
886 /*
887  * BPRM hooks
888  */
889 
890 /**
891  * smack_bprm_creds_for_exec - Update bprm->cred if needed for exec
892  * @bprm: the exec information
893  *
894  * Returns 0 if it gets a blob, -EPERM if exec forbidden and -ENOMEM otherwise
895  */
smack_bprm_creds_for_exec(struct linux_binprm *bprm)896 static int smack_bprm_creds_for_exec(struct linux_binprm *bprm)
897 {
898 	struct inode *inode = file_inode(bprm->file);
899 	struct task_smack *bsp = smack_cred(bprm->cred);
900 	struct inode_smack *isp;
901 	struct superblock_smack *sbsp;
902 	int rc;
903 
904 	isp = smack_inode(inode);
905 	if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task)
906 		return 0;
907 
908 	sbsp = inode->i_sb->s_security;
909 	if ((sbsp->smk_flags & SMK_SB_UNTRUSTED) &&
910 	    isp->smk_task != sbsp->smk_root)
911 		return 0;
912 
913 	if (bprm->unsafe & LSM_UNSAFE_PTRACE) {
914 		struct task_struct *tracer;
915 		rc = 0;
916 
917 		rcu_read_lock();
918 		tracer = ptrace_parent(current);
919 		if (likely(tracer != NULL))
920 			rc = smk_ptrace_rule_check(tracer,
921 						   isp->smk_task,
922 						   PTRACE_MODE_ATTACH,
923 						   __func__);
924 		rcu_read_unlock();
925 
926 		if (rc != 0)
927 			return rc;
928 	}
929 	if (bprm->unsafe & ~LSM_UNSAFE_PTRACE)
930 		return -EPERM;
931 
932 	bsp->smk_task = isp->smk_task;
933 	bprm->per_clear |= PER_CLEAR_ON_SETID;
934 
935 	/* Decide if this is a secure exec. */
936 	if (bsp->smk_task != bsp->smk_forked)
937 		bprm->secureexec = 1;
938 
939 	return 0;
940 }
941 
942 /*
943  * Inode hooks
944  */
945 
946 /**
947  * smack_inode_alloc_security - allocate an inode blob
948  * @inode: the inode in need of a blob
949  *
950  * Returns 0
951  */
smack_inode_alloc_security(struct inode *inode)952 static int smack_inode_alloc_security(struct inode *inode)
953 {
954 	struct smack_known *skp = smk_of_current();
955 
956 	init_inode_smack(inode, skp);
957 	return 0;
958 }
959 
960 /**
961  * smack_inode_init_security - copy out the smack from an inode
962  * @inode: the newly created inode
963  * @dir: containing directory object
964  * @qstr: unused
965  * @name: where to put the attribute name
966  * @value: where to put the attribute value
967  * @len: where to put the length of the attribute
968  *
969  * Returns 0 if it all works out, -ENOMEM if there's no memory
970  */
smack_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, const char **name, void **value, size_t *len)971 static int smack_inode_init_security(struct inode *inode, struct inode *dir,
972 				     const struct qstr *qstr, const char **name,
973 				     void **value, size_t *len)
974 {
975 	struct task_smack *tsp = smack_cred(current_cred());
976 	struct inode_smack *issp = smack_inode(inode);
977 	struct smack_known *skp = smk_of_task(tsp);
978 	struct smack_known *isp = smk_of_inode(inode);
979 	struct smack_known *dsp = smk_of_inode(dir);
980 	int may;
981 
982 	if (name)
983 		*name = XATTR_SMACK_SUFFIX;
984 
985 	if (value && len) {
986 		/*
987 		 * If equal, transmuting already occurred in
988 		 * smack_dentry_create_files_as(). No need to check again.
989 		 */
990 		if (tsp->smk_task != tsp->smk_transmuted) {
991 			rcu_read_lock();
992 			may = smk_access_entry(skp->smk_known, dsp->smk_known,
993 					       &skp->smk_rules);
994 			rcu_read_unlock();
995 		}
996 
997 		/*
998 		 * In addition to having smk_task equal to smk_transmuted,
999 		 * if the access rule allows transmutation and the directory
1000 		 * requests transmutation then by all means transmute.
1001 		 * Mark the inode as changed.
1002 		 */
1003 		if ((tsp->smk_task == tsp->smk_transmuted) ||
1004 		    (may > 0 && ((may & MAY_TRANSMUTE) != 0) &&
1005 		     smk_inode_transmutable(dir))) {
1006 			/*
1007 			 * The caller of smack_dentry_create_files_as()
1008 			 * should have overridden the current cred, so the
1009 			 * inode label was already set correctly in
1010 			 * smack_inode_alloc_security().
1011 			 */
1012 			if (tsp->smk_task != tsp->smk_transmuted)
1013 				isp = dsp;
1014 			issp->smk_flags |= SMK_INODE_CHANGED;
1015 		}
1016 
1017 		*value = kstrdup(isp->smk_known, GFP_NOFS);
1018 		if (*value == NULL)
1019 			return -ENOMEM;
1020 
1021 		*len = strlen(isp->smk_known);
1022 	}
1023 
1024 	return 0;
1025 }
1026 
1027 /**
1028  * smack_inode_link - Smack check on link
1029  * @old_dentry: the existing object
1030  * @dir: unused
1031  * @new_dentry: the new object
1032  *
1033  * Returns 0 if access is permitted, an error code otherwise
1034  */
smack_inode_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry)1035 static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
1036 			    struct dentry *new_dentry)
1037 {
1038 	struct smack_known *isp;
1039 	struct smk_audit_info ad;
1040 	int rc;
1041 
1042 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
1043 	smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);
1044 
1045 	isp = smk_of_inode(d_backing_inode(old_dentry));
1046 	rc = smk_curacc(isp, MAY_WRITE, &ad);
1047 	rc = smk_bu_inode(d_backing_inode(old_dentry), MAY_WRITE, rc);
1048 
1049 	if (rc == 0 && d_is_positive(new_dentry)) {
1050 		isp = smk_of_inode(d_backing_inode(new_dentry));
1051 		smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
1052 		rc = smk_curacc(isp, MAY_WRITE, &ad);
1053 		rc = smk_bu_inode(d_backing_inode(new_dentry), MAY_WRITE, rc);
1054 	}
1055 
1056 	return rc;
1057 }
1058 
1059 /**
1060  * smack_inode_unlink - Smack check on inode deletion
1061  * @dir: containing directory object
1062  * @dentry: file to unlink
1063  *
1064  * Returns 0 if current can write the containing directory
1065  * and the object, error code otherwise
1066  */
smack_inode_unlink(struct inode *dir, struct dentry *dentry)1067 static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
1068 {
1069 	struct inode *ip = d_backing_inode(dentry);
1070 	struct smk_audit_info ad;
1071 	int rc;
1072 
1073 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
1074 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
1075 
1076 	/*
1077 	 * You need write access to the thing you're unlinking
1078 	 */
1079 	rc = smk_curacc(smk_of_inode(ip), MAY_WRITE, &ad);
1080 	rc = smk_bu_inode(ip, MAY_WRITE, rc);
1081 	if (rc == 0) {
1082 		/*
1083 		 * You also need write access to the containing directory
1084 		 */
1085 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
1086 		smk_ad_setfield_u_fs_inode(&ad, dir);
1087 		rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
1088 		rc = smk_bu_inode(dir, MAY_WRITE, rc);
1089 	}
1090 	return rc;
1091 }
1092 
1093 /**
1094  * smack_inode_rmdir - Smack check on directory deletion
1095  * @dir: containing directory object
1096  * @dentry: directory to unlink
1097  *
1098  * Returns 0 if current can write the containing directory
1099  * and the directory, error code otherwise
1100  */
smack_inode_rmdir(struct inode *dir, struct dentry *dentry)1101 static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
1102 {
1103 	struct smk_audit_info ad;
1104 	int rc;
1105 
1106 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
1107 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
1108 
1109 	/*
1110 	 * You need write access to the thing you're removing
1111 	 */
1112 	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
1113 	rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
1114 	if (rc == 0) {
1115 		/*
1116 		 * You also need write access to the containing directory
1117 		 */
1118 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
1119 		smk_ad_setfield_u_fs_inode(&ad, dir);
1120 		rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
1121 		rc = smk_bu_inode(dir, MAY_WRITE, rc);
1122 	}
1123 
1124 	return rc;
1125 }
1126 
1127 /**
1128  * smack_inode_rename - Smack check on rename
1129  * @old_inode: unused
1130  * @old_dentry: the old object
1131  * @new_inode: unused
1132  * @new_dentry: the new object
1133  *
1134  * Read and write access is required on both the old and
1135  * new directories.
1136  *
1137  * Returns 0 if access is permitted, an error code otherwise
1138  */
smack_inode_rename(struct inode *old_inode, struct dentry *old_dentry, struct inode *new_inode, struct dentry *new_dentry)1139 static int smack_inode_rename(struct inode *old_inode,
1140 			      struct dentry *old_dentry,
1141 			      struct inode *new_inode,
1142 			      struct dentry *new_dentry)
1143 {
1144 	int rc;
1145 	struct smack_known *isp;
1146 	struct smk_audit_info ad;
1147 
1148 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
1149 	smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);
1150 
1151 	isp = smk_of_inode(d_backing_inode(old_dentry));
1152 	rc = smk_curacc(isp, MAY_READWRITE, &ad);
1153 	rc = smk_bu_inode(d_backing_inode(old_dentry), MAY_READWRITE, rc);
1154 
1155 	if (rc == 0 && d_is_positive(new_dentry)) {
1156 		isp = smk_of_inode(d_backing_inode(new_dentry));
1157 		smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
1158 		rc = smk_curacc(isp, MAY_READWRITE, &ad);
1159 		rc = smk_bu_inode(d_backing_inode(new_dentry), MAY_READWRITE, rc);
1160 	}
1161 	return rc;
1162 }
1163 
1164 /**
1165  * smack_inode_permission - Smack version of permission()
1166  * @inode: the inode in question
1167  * @mask: the access requested
1168  *
1169  * This is the important Smack hook.
1170  *
1171  * Returns 0 if access is permitted, an error code otherwise
1172  */
smack_inode_permission(struct inode *inode, int mask)1173 static int smack_inode_permission(struct inode *inode, int mask)
1174 {
1175 	struct superblock_smack *sbsp = inode->i_sb->s_security;
1176 	struct smk_audit_info ad;
1177 	int no_block = mask & MAY_NOT_BLOCK;
1178 	int rc;
1179 
1180 	mask &= (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND);
1181 	/*
1182 	 * No permission to check. Existence test. Yup, it's there.
1183 	 */
1184 	if (mask == 0)
1185 		return 0;
1186 
1187 	if (sbsp->smk_flags & SMK_SB_UNTRUSTED) {
1188 		if (smk_of_inode(inode) != sbsp->smk_root)
1189 			return -EACCES;
1190 	}
1191 
1192 	/* May be droppable after audit */
1193 	if (no_block)
1194 		return -ECHILD;
1195 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
1196 	smk_ad_setfield_u_fs_inode(&ad, inode);
1197 	rc = smk_curacc(smk_of_inode(inode), mask, &ad);
1198 	rc = smk_bu_inode(inode, mask, rc);
1199 	return rc;
1200 }
1201 
1202 /**
1203  * smack_inode_setattr - Smack check for setting attributes
1204  * @dentry: the object
1205  * @iattr: for the force flag
1206  *
1207  * Returns 0 if access is permitted, an error code otherwise
1208  */
smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)1209 static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
1210 {
1211 	struct smk_audit_info ad;
1212 	int rc;
1213 
1214 	/*
1215 	 * Need to allow for clearing the setuid bit.
1216 	 */
1217 	if (iattr->ia_valid & ATTR_FORCE)
1218 		return 0;
1219 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
1220 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
1221 
1222 	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
1223 	rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
1224 	return rc;
1225 }
1226 
1227 /**
1228  * smack_inode_getattr - Smack check for getting attributes
1229  * @path: path to extract the info from
1230  *
1231  * Returns 0 if access is permitted, an error code otherwise
1232  */
smack_inode_getattr(const struct path *path)1233 static int smack_inode_getattr(const struct path *path)
1234 {
1235 	struct smk_audit_info ad;
1236 	struct inode *inode = d_backing_inode(path->dentry);
1237 	int rc;
1238 
1239 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
1240 	smk_ad_setfield_u_fs_path(&ad, *path);
1241 	rc = smk_curacc(smk_of_inode(inode), MAY_READ, &ad);
1242 	rc = smk_bu_inode(inode, MAY_READ, rc);
1243 	return rc;
1244 }
1245 
1246 /**
1247  * smack_inode_setxattr - Smack check for setting xattrs
1248  * @dentry: the object
1249  * @name: name of the attribute
1250  * @value: value of the attribute
1251  * @size: size of the value
1252  * @flags: unused
1253  *
1254  * This protects the Smack attribute explicitly.
1255  *
1256  * Returns 0 if access is permitted, an error code otherwise
1257  */
smack_inode_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags)1258 static int smack_inode_setxattr(struct dentry *dentry, const char *name,
1259 				const void *value, size_t size, int flags)
1260 {
1261 	struct smk_audit_info ad;
1262 	struct smack_known *skp;
1263 	int check_priv = 0;
1264 	int check_import = 0;
1265 	int check_star = 0;
1266 	int rc = 0;
1267 
1268 	/*
1269 	 * Check label validity here so import won't fail in post_setxattr
1270 	 */
1271 	if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
1272 	    strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
1273 	    strcmp(name, XATTR_NAME_SMACKIPOUT) == 0) {
1274 		check_priv = 1;
1275 		check_import = 1;
1276 	} else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
1277 		   strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
1278 		check_priv = 1;
1279 		check_import = 1;
1280 		check_star = 1;
1281 	} else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
1282 		check_priv = 1;
1283 		if (size != TRANS_TRUE_SIZE ||
1284 		    strncmp(value, TRANS_TRUE, TRANS_TRUE_SIZE) != 0)
1285 			rc = -EINVAL;
1286 	} else
1287 		rc = cap_inode_setxattr(dentry, name, value, size, flags);
1288 
1289 	if (check_priv && !smack_privileged(CAP_MAC_ADMIN))
1290 		rc = -EPERM;
1291 
1292 	if (rc == 0 && check_import) {
1293 		skp = size ? smk_import_entry(value, size) : NULL;
1294 		if (IS_ERR(skp))
1295 			rc = PTR_ERR(skp);
1296 		else if (skp == NULL || (check_star &&
1297 		    (skp == &smack_known_star || skp == &smack_known_web)))
1298 			rc = -EINVAL;
1299 	}
1300 
1301 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
1302 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
1303 
1304 	if (rc == 0) {
1305 		rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
1306 		rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
1307 	}
1308 
1309 	return rc;
1310 }
1311 
1312 /**
1313  * smack_inode_post_setxattr - Apply the Smack update approved above
1314  * @dentry: object
1315  * @name: attribute name
1316  * @value: attribute value
1317  * @size: attribute size
1318  * @flags: unused
1319  *
1320  * Set the pointer in the inode blob to the entry found
1321  * in the master label list.
1322  */
smack_inode_post_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags)1323 static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
1324 				      const void *value, size_t size, int flags)
1325 {
1326 	struct smack_known *skp;
1327 	struct inode_smack *isp = smack_inode(d_backing_inode(dentry));
1328 
1329 	if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
1330 		isp->smk_flags |= SMK_INODE_TRANSMUTE;
1331 		return;
1332 	}
1333 
1334 	if (strcmp(name, XATTR_NAME_SMACK) == 0) {
1335 		skp = smk_import_entry(value, size);
1336 		if (!IS_ERR(skp))
1337 			isp->smk_inode = skp;
1338 	} else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0) {
1339 		skp = smk_import_entry(value, size);
1340 		if (!IS_ERR(skp))
1341 			isp->smk_task = skp;
1342 	} else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
1343 		skp = smk_import_entry(value, size);
1344 		if (!IS_ERR(skp))
1345 			isp->smk_mmap = skp;
1346 	}
1347 
1348 	return;
1349 }
1350 
1351 /**
1352  * smack_inode_getxattr - Smack check on getxattr
1353  * @dentry: the object
1354  * @name: unused
1355  *
1356  * Returns 0 if access is permitted, an error code otherwise
1357  */
smack_inode_getxattr(struct dentry *dentry, const char *name)1358 static int smack_inode_getxattr(struct dentry *dentry, const char *name)
1359 {
1360 	struct smk_audit_info ad;
1361 	int rc;
1362 
1363 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
1364 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
1365 
1366 	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_READ, &ad);
1367 	rc = smk_bu_inode(d_backing_inode(dentry), MAY_READ, rc);
1368 	return rc;
1369 }
1370 
1371 /**
1372  * smack_inode_removexattr - Smack check on removexattr
1373  * @dentry: the object
1374  * @name: name of the attribute
1375  *
1376  * Removing the Smack attribute requires CAP_MAC_ADMIN
1377  *
1378  * Returns 0 if access is permitted, an error code otherwise
1379  */
smack_inode_removexattr(struct dentry *dentry, const char *name)1380 static int smack_inode_removexattr(struct dentry *dentry, const char *name)
1381 {
1382 	struct inode_smack *isp;
1383 	struct smk_audit_info ad;
1384 	int rc = 0;
1385 
1386 	if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
1387 	    strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
1388 	    strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 ||
1389 	    strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
1390 	    strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0 ||
1391 	    strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
1392 		if (!smack_privileged(CAP_MAC_ADMIN))
1393 			rc = -EPERM;
1394 	} else
1395 		rc = cap_inode_removexattr(dentry, name);
1396 
1397 	if (rc != 0)
1398 		return rc;
1399 
1400 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
1401 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
1402 
1403 	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
1404 	rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
1405 	if (rc != 0)
1406 		return rc;
1407 
1408 	isp = smack_inode(d_backing_inode(dentry));
1409 	/*
1410 	 * Don't do anything special for these.
1411 	 *	XATTR_NAME_SMACKIPIN
1412 	 *	XATTR_NAME_SMACKIPOUT
1413 	 */
1414 	if (strcmp(name, XATTR_NAME_SMACK) == 0) {
1415 		struct super_block *sbp = dentry->d_sb;
1416 		struct superblock_smack *sbsp = sbp->s_security;
1417 
1418 		isp->smk_inode = sbsp->smk_default;
1419 	} else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0)
1420 		isp->smk_task = NULL;
1421 	else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0)
1422 		isp->smk_mmap = NULL;
1423 	else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0)
1424 		isp->smk_flags &= ~SMK_INODE_TRANSMUTE;
1425 
1426 	return 0;
1427 }
1428 
1429 /**
1430  * smack_inode_getsecurity - get smack xattrs
1431  * @inode: the object
1432  * @name: attribute name
1433  * @buffer: where to put the result
1434  * @alloc: duplicate memory
1435  *
1436  * Returns the size of the attribute or an error code
1437  */
smack_inode_getsecurity(struct inode *inode, const char *name, void **buffer, bool alloc)1438 static int smack_inode_getsecurity(struct inode *inode,
1439 				   const char *name, void **buffer,
1440 				   bool alloc)
1441 {
1442 	struct socket_smack *ssp;
1443 	struct socket *sock;
1444 	struct super_block *sbp;
1445 	struct inode *ip = (struct inode *)inode;
1446 	struct smack_known *isp;
1447 	struct inode_smack *ispp;
1448 	size_t label_len;
1449 	char *label = NULL;
1450 
1451 	if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
1452 		isp = smk_of_inode(inode);
1453 	} else if (strcmp(name, XATTR_SMACK_TRANSMUTE) == 0) {
1454 		ispp = smack_inode(inode);
1455 		if (ispp->smk_flags & SMK_INODE_TRANSMUTE)
1456 			label = TRANS_TRUE;
1457 		else
1458 			label = "";
1459 	} else {
1460 		/*
1461 		 * The rest of the Smack xattrs are only on sockets.
1462 		 */
1463 		sbp = ip->i_sb;
1464 		if (sbp->s_magic != SOCKFS_MAGIC)
1465 			return -EOPNOTSUPP;
1466 
1467 		sock = SOCKET_I(ip);
1468 		if (sock == NULL || sock->sk == NULL)
1469 			return -EOPNOTSUPP;
1470 
1471 		ssp = sock->sk->sk_security;
1472 
1473 		if (strcmp(name, XATTR_SMACK_IPIN) == 0)
1474 			isp = ssp->smk_in;
1475 		else if (strcmp(name, XATTR_SMACK_IPOUT) == 0)
1476 			isp = ssp->smk_out;
1477 		else
1478 			return -EOPNOTSUPP;
1479 	}
1480 
1481 	if (!label)
1482 		label = isp->smk_known;
1483 
1484 	label_len = strlen(label);
1485 
1486 	if (alloc) {
1487 		*buffer = kstrdup(label, GFP_KERNEL);
1488 		if (*buffer == NULL)
1489 			return -ENOMEM;
1490 	}
1491 
1492 	return label_len;
1493 }
1494 
1495 
1496 /**
1497  * smack_inode_listsecurity - list the Smack attributes
1498  * @inode: the object
1499  * @buffer: where they go
1500  * @buffer_size: size of buffer
1501  */
smack_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size)1502 static int smack_inode_listsecurity(struct inode *inode, char *buffer,
1503 				    size_t buffer_size)
1504 {
1505 	int len = sizeof(XATTR_NAME_SMACK);
1506 
1507 	if (buffer != NULL && len <= buffer_size)
1508 		memcpy(buffer, XATTR_NAME_SMACK, len);
1509 
1510 	return len;
1511 }
1512 
1513 /**
1514  * smack_inode_getsecid - Extract inode's security id
1515  * @inode: inode to extract the info from
1516  * @secid: where result will be saved
1517  */
smack_inode_getsecid(struct inode *inode, u32 *secid)1518 static void smack_inode_getsecid(struct inode *inode, u32 *secid)
1519 {
1520 	struct smack_known *skp = smk_of_inode(inode);
1521 
1522 	*secid = skp->smk_secid;
1523 }
1524 
1525 /*
1526  * File Hooks
1527  */
1528 
1529 /*
1530  * There is no smack_file_permission hook
1531  *
1532  * Should access checks be done on each read or write?
1533  * UNICOS and SELinux say yes.
1534  * Trusted Solaris, Trusted Irix, and just about everyone else says no.
1535  *
1536  * I'll say no for now. Smack does not do the frequent
1537  * label changing that SELinux does.
1538  */
1539 
1540 /**
1541  * smack_file_alloc_security - assign a file security blob
1542  * @file: the object
1543  *
1544  * The security blob for a file is a pointer to the master
1545  * label list, so no allocation is done.
1546  *
1547  * f_security is the owner security information. It
1548  * isn't used on file access checks, it's for send_sigio.
1549  *
1550  * Returns 0
1551  */
smack_file_alloc_security(struct file *file)1552 static int smack_file_alloc_security(struct file *file)
1553 {
1554 	struct smack_known **blob = smack_file(file);
1555 
1556 	*blob = smk_of_current();
1557 	return 0;
1558 }
1559 
1560 /**
1561  * smack_file_ioctl - Smack check on ioctls
1562  * @file: the object
1563  * @cmd: what to do
1564  * @arg: unused
1565  *
1566  * Relies heavily on the correct use of the ioctl command conventions.
1567  *
1568  * Returns 0 if allowed, error code otherwise
1569  */
smack_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg)1570 static int smack_file_ioctl(struct file *file, unsigned int cmd,
1571 			    unsigned long arg)
1572 {
1573 	int rc = 0;
1574 	struct smk_audit_info ad;
1575 	struct inode *inode = file_inode(file);
1576 
1577 	if (unlikely(IS_PRIVATE(inode)))
1578 		return 0;
1579 
1580 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
1581 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
1582 
1583 	if (_IOC_DIR(cmd) & _IOC_WRITE) {
1584 		rc = smk_curacc(smk_of_inode(inode), MAY_WRITE, &ad);
1585 		rc = smk_bu_file(file, MAY_WRITE, rc);
1586 	}
1587 
1588 	if (rc == 0 && (_IOC_DIR(cmd) & _IOC_READ)) {
1589 		rc = smk_curacc(smk_of_inode(inode), MAY_READ, &ad);
1590 		rc = smk_bu_file(file, MAY_READ, rc);
1591 	}
1592 
1593 	return rc;
1594 }
1595 
1596 /**
1597  * smack_file_lock - Smack check on file locking
1598  * @file: the object
1599  * @cmd: unused
1600  *
1601  * Returns 0 if current has lock access, error code otherwise
1602  */
smack_file_lock(struct file *file, unsigned int cmd)1603 static int smack_file_lock(struct file *file, unsigned int cmd)
1604 {
1605 	struct smk_audit_info ad;
1606 	int rc;
1607 	struct inode *inode = file_inode(file);
1608 
1609 	if (unlikely(IS_PRIVATE(inode)))
1610 		return 0;
1611 
1612 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
1613 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
1614 	rc = smk_curacc(smk_of_inode(inode), MAY_LOCK, &ad);
1615 	rc = smk_bu_file(file, MAY_LOCK, rc);
1616 	return rc;
1617 }
1618 
1619 /**
1620  * smack_file_fcntl - Smack check on fcntl
1621  * @file: the object
1622  * @cmd: what action to check
1623  * @arg: unused
1624  *
1625  * Generally these operations are harmless.
1626  * File locking operations present an obvious mechanism
1627  * for passing information, so they require write access.
1628  *
1629  * Returns 0 if current has access, error code otherwise
1630  */
smack_file_fcntl(struct file *file, unsigned int cmd, unsigned long arg)1631 static int smack_file_fcntl(struct file *file, unsigned int cmd,
1632 			    unsigned long arg)
1633 {
1634 	struct smk_audit_info ad;
1635 	int rc = 0;
1636 	struct inode *inode = file_inode(file);
1637 
1638 	if (unlikely(IS_PRIVATE(inode)))
1639 		return 0;
1640 
1641 	switch (cmd) {
1642 	case F_GETLK:
1643 		break;
1644 	case F_SETLK:
1645 	case F_SETLKW:
1646 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
1647 		smk_ad_setfield_u_fs_path(&ad, file->f_path);
1648 		rc = smk_curacc(smk_of_inode(inode), MAY_LOCK, &ad);
1649 		rc = smk_bu_file(file, MAY_LOCK, rc);
1650 		break;
1651 	case F_SETOWN:
1652 	case F_SETSIG:
1653 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
1654 		smk_ad_setfield_u_fs_path(&ad, file->f_path);
1655 		rc = smk_curacc(smk_of_inode(inode), MAY_WRITE, &ad);
1656 		rc = smk_bu_file(file, MAY_WRITE, rc);
1657 		break;
1658 	default:
1659 		break;
1660 	}
1661 
1662 	return rc;
1663 }
1664 
1665 /**
1666  * smack_mmap_file :
1667  * Check permissions for a mmap operation.  The @file may be NULL, e.g.
1668  * if mapping anonymous memory.
1669  * @file contains the file structure for file to map (may be NULL).
1670  * @reqprot contains the protection requested by the application.
1671  * @prot contains the protection that will be applied by the kernel.
1672  * @flags contains the operational flags.
1673  * Return 0 if permission is granted.
1674  */
smack_mmap_file(struct file *file, unsigned long reqprot, unsigned long prot, unsigned long flags)1675 static int smack_mmap_file(struct file *file,
1676 			   unsigned long reqprot, unsigned long prot,
1677 			   unsigned long flags)
1678 {
1679 	struct smack_known *skp;
1680 	struct smack_known *mkp;
1681 	struct smack_rule *srp;
1682 	struct task_smack *tsp;
1683 	struct smack_known *okp;
1684 	struct inode_smack *isp;
1685 	struct superblock_smack *sbsp;
1686 	int may;
1687 	int mmay;
1688 	int tmay;
1689 	int rc;
1690 
1691 	if (file == NULL)
1692 		return 0;
1693 
1694 	if (unlikely(IS_PRIVATE(file_inode(file))))
1695 		return 0;
1696 
1697 	isp = smack_inode(file_inode(file));
1698 	if (isp->smk_mmap == NULL)
1699 		return 0;
1700 	sbsp = file_inode(file)->i_sb->s_security;
1701 	if (sbsp->smk_flags & SMK_SB_UNTRUSTED &&
1702 	    isp->smk_mmap != sbsp->smk_root)
1703 		return -EACCES;
1704 	mkp = isp->smk_mmap;
1705 
1706 	tsp = smack_cred(current_cred());
1707 	skp = smk_of_current();
1708 	rc = 0;
1709 
1710 	rcu_read_lock();
1711 	/*
1712 	 * For each Smack rule associated with the subject
1713 	 * label verify that the SMACK64MMAP also has access
1714 	 * to that rule's object label.
1715 	 */
1716 	list_for_each_entry_rcu(srp, &skp->smk_rules, list) {
1717 		okp = srp->smk_object;
1718 		/*
1719 		 * Matching labels always allows access.
1720 		 */
1721 		if (mkp->smk_known == okp->smk_known)
1722 			continue;
1723 		/*
1724 		 * If there is a matching local rule take
1725 		 * that into account as well.
1726 		 */
1727 		may = smk_access_entry(srp->smk_subject->smk_known,
1728 				       okp->smk_known,
1729 				       &tsp->smk_rules);
1730 		if (may == -ENOENT)
1731 			may = srp->smk_access;
1732 		else
1733 			may &= srp->smk_access;
1734 		/*
1735 		 * If may is zero the SMACK64MMAP subject can't
1736 		 * possibly have less access.
1737 		 */
1738 		if (may == 0)
1739 			continue;
1740 
1741 		/*
1742 		 * Fetch the global list entry.
1743 		 * If there isn't one a SMACK64MMAP subject
1744 		 * can't have as much access as current.
1745 		 */
1746 		mmay = smk_access_entry(mkp->smk_known, okp->smk_known,
1747 					&mkp->smk_rules);
1748 		if (mmay == -ENOENT) {
1749 			rc = -EACCES;
1750 			break;
1751 		}
1752 		/*
1753 		 * If there is a local entry it modifies the
1754 		 * potential access, too.
1755 		 */
1756 		tmay = smk_access_entry(mkp->smk_known, okp->smk_known,
1757 					&tsp->smk_rules);
1758 		if (tmay != -ENOENT)
1759 			mmay &= tmay;
1760 
1761 		/*
1762 		 * If there is any access available to current that is
1763 		 * not available to a SMACK64MMAP subject
1764 		 * deny access.
1765 		 */
1766 		if ((may | mmay) != mmay) {
1767 			rc = -EACCES;
1768 			break;
1769 		}
1770 	}
1771 
1772 	rcu_read_unlock();
1773 
1774 	return rc;
1775 }
1776 
1777 /**
1778  * smack_file_set_fowner - set the file security blob value
1779  * @file: object in question
1780  *
1781  */
smack_file_set_fowner(struct file *file)1782 static void smack_file_set_fowner(struct file *file)
1783 {
1784 	struct smack_known **blob = smack_file(file);
1785 
1786 	*blob = smk_of_current();
1787 }
1788 
1789 /**
1790  * smack_file_send_sigiotask - Smack on sigio
1791  * @tsk: The target task
1792  * @fown: the object the signal come from
1793  * @signum: unused
1794  *
1795  * Allow a privileged task to get signals even if it shouldn't
1796  *
1797  * Returns 0 if a subject with the object's smack could
1798  * write to the task, an error code otherwise.
1799  */
smack_file_send_sigiotask(struct task_struct *tsk, struct fown_struct *fown, int signum)1800 static int smack_file_send_sigiotask(struct task_struct *tsk,
1801 				     struct fown_struct *fown, int signum)
1802 {
1803 	struct smack_known **blob;
1804 	struct smack_known *skp;
1805 	struct smack_known *tkp = smk_of_task(smack_cred(tsk->cred));
1806 	const struct cred *tcred;
1807 	struct file *file;
1808 	int rc;
1809 	struct smk_audit_info ad;
1810 
1811 	/*
1812 	 * struct fown_struct is never outside the context of a struct file
1813 	 */
1814 	file = container_of(fown, struct file, f_owner);
1815 
1816 	/* we don't log here as rc can be overriden */
1817 	blob = smack_file(file);
1818 	skp = *blob;
1819 	rc = smk_access(skp, tkp, MAY_DELIVER, NULL);
1820 	rc = smk_bu_note("sigiotask", skp, tkp, MAY_DELIVER, rc);
1821 
1822 	rcu_read_lock();
1823 	tcred = __task_cred(tsk);
1824 	if (rc != 0 && smack_privileged_cred(CAP_MAC_OVERRIDE, tcred))
1825 		rc = 0;
1826 	rcu_read_unlock();
1827 
1828 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
1829 	smk_ad_setfield_u_tsk(&ad, tsk);
1830 	smack_log(skp->smk_known, tkp->smk_known, MAY_DELIVER, rc, &ad);
1831 	return rc;
1832 }
1833 
1834 /**
1835  * smack_file_receive - Smack file receive check
1836  * @file: the object
1837  *
1838  * Returns 0 if current has access, error code otherwise
1839  */
smack_file_receive(struct file *file)1840 static int smack_file_receive(struct file *file)
1841 {
1842 	int rc;
1843 	int may = 0;
1844 	struct smk_audit_info ad;
1845 	struct inode *inode = file_inode(file);
1846 	struct socket *sock;
1847 	struct task_smack *tsp;
1848 	struct socket_smack *ssp;
1849 
1850 	if (unlikely(IS_PRIVATE(inode)))
1851 		return 0;
1852 
1853 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
1854 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
1855 
1856 	if (inode->i_sb->s_magic == SOCKFS_MAGIC) {
1857 		sock = SOCKET_I(inode);
1858 		ssp = sock->sk->sk_security;
1859 		tsp = smack_cred(current_cred());
1860 		/*
1861 		 * If the receiving process can't write to the
1862 		 * passed socket or if the passed socket can't
1863 		 * write to the receiving process don't accept
1864 		 * the passed socket.
1865 		 */
1866 		rc = smk_access(tsp->smk_task, ssp->smk_out, MAY_WRITE, &ad);
1867 		rc = smk_bu_file(file, may, rc);
1868 		if (rc < 0)
1869 			return rc;
1870 		rc = smk_access(ssp->smk_in, tsp->smk_task, MAY_WRITE, &ad);
1871 		rc = smk_bu_file(file, may, rc);
1872 		return rc;
1873 	}
1874 	/*
1875 	 * This code relies on bitmasks.
1876 	 */
1877 	if (file->f_mode & FMODE_READ)
1878 		may = MAY_READ;
1879 	if (file->f_mode & FMODE_WRITE)
1880 		may |= MAY_WRITE;
1881 
1882 	rc = smk_curacc(smk_of_inode(inode), may, &ad);
1883 	rc = smk_bu_file(file, may, rc);
1884 	return rc;
1885 }
1886 
1887 /**
1888  * smack_file_open - Smack dentry open processing
1889  * @file: the object
1890  *
1891  * Set the security blob in the file structure.
1892  * Allow the open only if the task has read access. There are
1893  * many read operations (e.g. fstat) that you can do with an
1894  * fd even if you have the file open write-only.
1895  *
1896  * Returns 0 if current has access, error code otherwise
1897  */
smack_file_open(struct file *file)1898 static int smack_file_open(struct file *file)
1899 {
1900 	struct task_smack *tsp = smack_cred(file->f_cred);
1901 	struct inode *inode = file_inode(file);
1902 	struct smk_audit_info ad;
1903 	int rc;
1904 
1905 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
1906 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
1907 	rc = smk_tskacc(tsp, smk_of_inode(inode), MAY_READ, &ad);
1908 	rc = smk_bu_credfile(file->f_cred, file, MAY_READ, rc);
1909 
1910 	return rc;
1911 }
1912 
1913 /*
1914  * Task hooks
1915  */
1916 
1917 /**
1918  * smack_cred_alloc_blank - "allocate" blank task-level security credentials
1919  * @cred: the new credentials
1920  * @gfp: the atomicity of any memory allocations
1921  *
1922  * Prepare a blank set of credentials for modification.  This must allocate all
1923  * the memory the LSM module might require such that cred_transfer() can
1924  * complete without error.
1925  */
smack_cred_alloc_blank(struct cred *cred, gfp_t gfp)1926 static int smack_cred_alloc_blank(struct cred *cred, gfp_t gfp)
1927 {
1928 	init_task_smack(smack_cred(cred), NULL, NULL);
1929 	return 0;
1930 }
1931 
1932 
1933 /**
1934  * smack_cred_free - "free" task-level security credentials
1935  * @cred: the credentials in question
1936  *
1937  */
smack_cred_free(struct cred *cred)1938 static void smack_cred_free(struct cred *cred)
1939 {
1940 	struct task_smack *tsp = smack_cred(cred);
1941 	struct smack_rule *rp;
1942 	struct list_head *l;
1943 	struct list_head *n;
1944 
1945 	smk_destroy_label_list(&tsp->smk_relabel);
1946 
1947 	list_for_each_safe(l, n, &tsp->smk_rules) {
1948 		rp = list_entry(l, struct smack_rule, list);
1949 		list_del(&rp->list);
1950 		kmem_cache_free(smack_rule_cache, rp);
1951 	}
1952 }
1953 
1954 /**
1955  * smack_cred_prepare - prepare new set of credentials for modification
1956  * @new: the new credentials
1957  * @old: the original credentials
1958  * @gfp: the atomicity of any memory allocations
1959  *
1960  * Prepare a new set of credentials for modification.
1961  */
smack_cred_prepare(struct cred *new, const struct cred *old, gfp_t gfp)1962 static int smack_cred_prepare(struct cred *new, const struct cred *old,
1963 			      gfp_t gfp)
1964 {
1965 	struct task_smack *old_tsp = smack_cred(old);
1966 	struct task_smack *new_tsp = smack_cred(new);
1967 	int rc;
1968 
1969 	init_task_smack(new_tsp, old_tsp->smk_task, old_tsp->smk_task);
1970 
1971 	rc = smk_copy_rules(&new_tsp->smk_rules, &old_tsp->smk_rules, gfp);
1972 	if (rc != 0)
1973 		return rc;
1974 
1975 	rc = smk_copy_relabel(&new_tsp->smk_relabel, &old_tsp->smk_relabel,
1976 				gfp);
1977 	return rc;
1978 }
1979 
1980 /**
1981  * smack_cred_transfer - Transfer the old credentials to the new credentials
1982  * @new: the new credentials
1983  * @old: the original credentials
1984  *
1985  * Fill in a set of blank credentials from another set of credentials.
1986  */
smack_cred_transfer(struct cred *new, const struct cred *old)1987 static void smack_cred_transfer(struct cred *new, const struct cred *old)
1988 {
1989 	struct task_smack *old_tsp = smack_cred(old);
1990 	struct task_smack *new_tsp = smack_cred(new);
1991 
1992 	new_tsp->smk_task = old_tsp->smk_task;
1993 	new_tsp->smk_forked = old_tsp->smk_task;
1994 	mutex_init(&new_tsp->smk_rules_lock);
1995 	INIT_LIST_HEAD(&new_tsp->smk_rules);
1996 
1997 	/* cbs copy rule list */
1998 }
1999 
2000 /**
2001  * smack_cred_getsecid - get the secid corresponding to a creds structure
2002  * @cred: the object creds
2003  * @secid: where to put the result
2004  *
2005  * Sets the secid to contain a u32 version of the smack label.
2006  */
smack_cred_getsecid(const struct cred *cred, u32 *secid)2007 static void smack_cred_getsecid(const struct cred *cred, u32 *secid)
2008 {
2009 	struct smack_known *skp;
2010 
2011 	rcu_read_lock();
2012 	skp = smk_of_task(smack_cred(cred));
2013 	*secid = skp->smk_secid;
2014 	rcu_read_unlock();
2015 }
2016 
2017 /**
2018  * smack_kernel_act_as - Set the subjective context in a set of credentials
2019  * @new: points to the set of credentials to be modified.
2020  * @secid: specifies the security ID to be set
2021  *
2022  * Set the security data for a kernel service.
2023  */
smack_kernel_act_as(struct cred *new, u32 secid)2024 static int smack_kernel_act_as(struct cred *new, u32 secid)
2025 {
2026 	struct task_smack *new_tsp = smack_cred(new);
2027 
2028 	new_tsp->smk_task = smack_from_secid(secid);
2029 	return 0;
2030 }
2031 
2032 /**
2033  * smack_kernel_create_files_as - Set the file creation label in a set of creds
2034  * @new: points to the set of credentials to be modified
2035  * @inode: points to the inode to use as a reference
2036  *
2037  * Set the file creation context in a set of credentials to the same
2038  * as the objective context of the specified inode
2039  */
smack_kernel_create_files_as(struct cred *new, struct inode *inode)2040 static int smack_kernel_create_files_as(struct cred *new,
2041 					struct inode *inode)
2042 {
2043 	struct inode_smack *isp = smack_inode(inode);
2044 	struct task_smack *tsp = smack_cred(new);
2045 
2046 	tsp->smk_forked = isp->smk_inode;
2047 	tsp->smk_task = tsp->smk_forked;
2048 	return 0;
2049 }
2050 
2051 /**
2052  * smk_curacc_on_task - helper to log task related access
2053  * @p: the task object
2054  * @access: the access requested
2055  * @caller: name of the calling function for audit
2056  *
2057  * Return 0 if access is permitted
2058  */
smk_curacc_on_task(struct task_struct *p, int access, const char *caller)2059 static int smk_curacc_on_task(struct task_struct *p, int access,
2060 				const char *caller)
2061 {
2062 	struct smk_audit_info ad;
2063 	struct smack_known *skp = smk_of_task_struct(p);
2064 	int rc;
2065 
2066 	smk_ad_init(&ad, caller, LSM_AUDIT_DATA_TASK);
2067 	smk_ad_setfield_u_tsk(&ad, p);
2068 	rc = smk_curacc(skp, access, &ad);
2069 	rc = smk_bu_task(p, access, rc);
2070 	return rc;
2071 }
2072 
2073 /**
2074  * smack_task_setpgid - Smack check on setting pgid
2075  * @p: the task object
2076  * @pgid: unused
2077  *
2078  * Return 0 if write access is permitted
2079  */
smack_task_setpgid(struct task_struct *p, pid_t pgid)2080 static int smack_task_setpgid(struct task_struct *p, pid_t pgid)
2081 {
2082 	return smk_curacc_on_task(p, MAY_WRITE, __func__);
2083 }
2084 
2085 /**
2086  * smack_task_getpgid - Smack access check for getpgid
2087  * @p: the object task
2088  *
2089  * Returns 0 if current can read the object task, error code otherwise
2090  */
smack_task_getpgid(struct task_struct *p)2091 static int smack_task_getpgid(struct task_struct *p)
2092 {
2093 	return smk_curacc_on_task(p, MAY_READ, __func__);
2094 }
2095 
2096 /**
2097  * smack_task_getsid - Smack access check for getsid
2098  * @p: the object task
2099  *
2100  * Returns 0 if current can read the object task, error code otherwise
2101  */
smack_task_getsid(struct task_struct *p)2102 static int smack_task_getsid(struct task_struct *p)
2103 {
2104 	return smk_curacc_on_task(p, MAY_READ, __func__);
2105 }
2106 
2107 /**
2108  * smack_task_getsecid - get the secid of the task
2109  * @p: the object task
2110  * @secid: where to put the result
2111  *
2112  * Sets the secid to contain a u32 version of the smack label.
2113  */
smack_task_getsecid(struct task_struct *p, u32 *secid)2114 static void smack_task_getsecid(struct task_struct *p, u32 *secid)
2115 {
2116 	struct smack_known *skp = smk_of_task_struct(p);
2117 
2118 	*secid = skp->smk_secid;
2119 }
2120 
2121 /**
2122  * smack_task_setnice - Smack check on setting nice
2123  * @p: the task object
2124  * @nice: unused
2125  *
2126  * Return 0 if write access is permitted
2127  */
smack_task_setnice(struct task_struct *p, int nice)2128 static int smack_task_setnice(struct task_struct *p, int nice)
2129 {
2130 	return smk_curacc_on_task(p, MAY_WRITE, __func__);
2131 }
2132 
2133 /**
2134  * smack_task_setioprio - Smack check on setting ioprio
2135  * @p: the task object
2136  * @ioprio: unused
2137  *
2138  * Return 0 if write access is permitted
2139  */
smack_task_setioprio(struct task_struct *p, int ioprio)2140 static int smack_task_setioprio(struct task_struct *p, int ioprio)
2141 {
2142 	return smk_curacc_on_task(p, MAY_WRITE, __func__);
2143 }
2144 
2145 /**
2146  * smack_task_getioprio - Smack check on reading ioprio
2147  * @p: the task object
2148  *
2149  * Return 0 if read access is permitted
2150  */
smack_task_getioprio(struct task_struct *p)2151 static int smack_task_getioprio(struct task_struct *p)
2152 {
2153 	return smk_curacc_on_task(p, MAY_READ, __func__);
2154 }
2155 
2156 /**
2157  * smack_task_setscheduler - Smack check on setting scheduler
2158  * @p: the task object
2159  *
2160  * Return 0 if read access is permitted
2161  */
smack_task_setscheduler(struct task_struct *p)2162 static int smack_task_setscheduler(struct task_struct *p)
2163 {
2164 	return smk_curacc_on_task(p, MAY_WRITE, __func__);
2165 }
2166 
2167 /**
2168  * smack_task_getscheduler - Smack check on reading scheduler
2169  * @p: the task object
2170  *
2171  * Return 0 if read access is permitted
2172  */
smack_task_getscheduler(struct task_struct *p)2173 static int smack_task_getscheduler(struct task_struct *p)
2174 {
2175 	return smk_curacc_on_task(p, MAY_READ, __func__);
2176 }
2177 
2178 /**
2179  * smack_task_movememory - Smack check on moving memory
2180  * @p: the task object
2181  *
2182  * Return 0 if write access is permitted
2183  */
smack_task_movememory(struct task_struct *p)2184 static int smack_task_movememory(struct task_struct *p)
2185 {
2186 	return smk_curacc_on_task(p, MAY_WRITE, __func__);
2187 }
2188 
2189 /**
2190  * smack_task_kill - Smack check on signal delivery
2191  * @p: the task object
2192  * @info: unused
2193  * @sig: unused
2194  * @cred: identifies the cred to use in lieu of current's
2195  *
2196  * Return 0 if write access is permitted
2197  *
2198  */
smack_task_kill(struct task_struct *p, struct kernel_siginfo *info, int sig, const struct cred *cred)2199 static int smack_task_kill(struct task_struct *p, struct kernel_siginfo *info,
2200 			   int sig, const struct cred *cred)
2201 {
2202 	struct smk_audit_info ad;
2203 	struct smack_known *skp;
2204 	struct smack_known *tkp = smk_of_task_struct(p);
2205 	int rc;
2206 
2207 	if (!sig)
2208 		return 0; /* null signal; existence test */
2209 
2210 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
2211 	smk_ad_setfield_u_tsk(&ad, p);
2212 	/*
2213 	 * Sending a signal requires that the sender
2214 	 * can write the receiver.
2215 	 */
2216 	if (cred == NULL) {
2217 		rc = smk_curacc(tkp, MAY_DELIVER, &ad);
2218 		rc = smk_bu_task(p, MAY_DELIVER, rc);
2219 		return rc;
2220 	}
2221 	/*
2222 	 * If the cred isn't NULL we're dealing with some USB IO
2223 	 * specific behavior. This is not clean. For one thing
2224 	 * we can't take privilege into account.
2225 	 */
2226 	skp = smk_of_task(smack_cred(cred));
2227 	rc = smk_access(skp, tkp, MAY_DELIVER, &ad);
2228 	rc = smk_bu_note("USB signal", skp, tkp, MAY_DELIVER, rc);
2229 	return rc;
2230 }
2231 
2232 /**
2233  * smack_task_to_inode - copy task smack into the inode blob
2234  * @p: task to copy from
2235  * @inode: inode to copy to
2236  *
2237  * Sets the smack pointer in the inode security blob
2238  */
smack_task_to_inode(struct task_struct *p, struct inode *inode)2239 static void smack_task_to_inode(struct task_struct *p, struct inode *inode)
2240 {
2241 	struct inode_smack *isp = smack_inode(inode);
2242 	struct smack_known *skp = smk_of_task_struct(p);
2243 
2244 	isp->smk_inode = skp;
2245 	isp->smk_flags |= SMK_INODE_INSTANT;
2246 }
2247 
2248 /*
2249  * Socket hooks.
2250  */
2251 
2252 /**
2253  * smack_sk_alloc_security - Allocate a socket blob
2254  * @sk: the socket
2255  * @family: unused
2256  * @gfp_flags: memory allocation flags
2257  *
2258  * Assign Smack pointers to current
2259  *
2260  * Returns 0 on success, -ENOMEM is there's no memory
2261  */
smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)2262 static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
2263 {
2264 	struct smack_known *skp = smk_of_current();
2265 	struct socket_smack *ssp;
2266 
2267 	ssp = kzalloc(sizeof(struct socket_smack), gfp_flags);
2268 	if (ssp == NULL)
2269 		return -ENOMEM;
2270 
2271 	/*
2272 	 * Sockets created by kernel threads receive web label.
2273 	 */
2274 	if (unlikely(current->flags & PF_KTHREAD)) {
2275 		ssp->smk_in = &smack_known_web;
2276 		ssp->smk_out = &smack_known_web;
2277 	} else {
2278 		ssp->smk_in = skp;
2279 		ssp->smk_out = skp;
2280 	}
2281 	ssp->smk_packet = NULL;
2282 
2283 	sk->sk_security = ssp;
2284 
2285 	return 0;
2286 }
2287 
2288 /**
2289  * smack_sk_free_security - Free a socket blob
2290  * @sk: the socket
2291  *
2292  * Clears the blob pointer
2293  */
smack_sk_free_security(struct sock *sk)2294 static void smack_sk_free_security(struct sock *sk)
2295 {
2296 #ifdef SMACK_IPV6_PORT_LABELING
2297 	struct smk_port_label *spp;
2298 
2299 	if (sk->sk_family == PF_INET6) {
2300 		rcu_read_lock();
2301 		list_for_each_entry_rcu(spp, &smk_ipv6_port_list, list) {
2302 			if (spp->smk_sock != sk)
2303 				continue;
2304 			spp->smk_can_reuse = 1;
2305 			break;
2306 		}
2307 		rcu_read_unlock();
2308 	}
2309 #endif
2310 	kfree(sk->sk_security);
2311 }
2312 
2313 /**
2314 * smack_ipv4host_label - check host based restrictions
2315 * @sip: the object end
2316 *
2317 * looks for host based access restrictions
2318 *
2319 * This version will only be appropriate for really small sets of single label
2320 * hosts.  The caller is responsible for ensuring that the RCU read lock is
2321 * taken before calling this function.
2322 *
2323 * Returns the label of the far end or NULL if it's not special.
2324 */
smack_ipv4host_label(struct sockaddr_in *sip)2325 static struct smack_known *smack_ipv4host_label(struct sockaddr_in *sip)
2326 {
2327 	struct smk_net4addr *snp;
2328 	struct in_addr *siap = &sip->sin_addr;
2329 
2330 	if (siap->s_addr == 0)
2331 		return NULL;
2332 
2333 	list_for_each_entry_rcu(snp, &smk_net4addr_list, list)
2334 		/*
2335 		 * we break after finding the first match because
2336 		 * the list is sorted from longest to shortest mask
2337 		 * so we have found the most specific match
2338 		 */
2339 		if (snp->smk_host.s_addr ==
2340 		    (siap->s_addr & snp->smk_mask.s_addr))
2341 			return snp->smk_label;
2342 
2343 	return NULL;
2344 }
2345 
2346 /*
2347  * smk_ipv6_localhost - Check for local ipv6 host address
2348  * @sip: the address
2349  *
2350  * Returns boolean true if this is the localhost address
2351  */
smk_ipv6_localhost(struct sockaddr_in6 *sip)2352 static bool smk_ipv6_localhost(struct sockaddr_in6 *sip)
2353 {
2354 	__be16 *be16p = (__be16 *)&sip->sin6_addr;
2355 	__be32 *be32p = (__be32 *)&sip->sin6_addr;
2356 
2357 	if (be32p[0] == 0 && be32p[1] == 0 && be32p[2] == 0 && be16p[6] == 0 &&
2358 	    ntohs(be16p[7]) == 1)
2359 		return true;
2360 	return false;
2361 }
2362 
2363 /**
2364 * smack_ipv6host_label - check host based restrictions
2365 * @sip: the object end
2366 *
2367 * looks for host based access restrictions
2368 *
2369 * This version will only be appropriate for really small sets of single label
2370 * hosts.  The caller is responsible for ensuring that the RCU read lock is
2371 * taken before calling this function.
2372 *
2373 * Returns the label of the far end or NULL if it's not special.
2374 */
smack_ipv6host_label(struct sockaddr_in6 *sip)2375 static struct smack_known *smack_ipv6host_label(struct sockaddr_in6 *sip)
2376 {
2377 	struct smk_net6addr *snp;
2378 	struct in6_addr *sap = &sip->sin6_addr;
2379 	int i;
2380 	int found = 0;
2381 
2382 	/*
2383 	 * It's local. Don't look for a host label.
2384 	 */
2385 	if (smk_ipv6_localhost(sip))
2386 		return NULL;
2387 
2388 	list_for_each_entry_rcu(snp, &smk_net6addr_list, list) {
2389 		/*
2390 		 * If the label is NULL the entry has
2391 		 * been renounced. Ignore it.
2392 		 */
2393 		if (snp->smk_label == NULL)
2394 			continue;
2395 		/*
2396 		* we break after finding the first match because
2397 		* the list is sorted from longest to shortest mask
2398 		* so we have found the most specific match
2399 		*/
2400 		for (found = 1, i = 0; i < 8; i++) {
2401 			if ((sap->s6_addr16[i] & snp->smk_mask.s6_addr16[i]) !=
2402 			    snp->smk_host.s6_addr16[i]) {
2403 				found = 0;
2404 				break;
2405 			}
2406 		}
2407 		if (found)
2408 			return snp->smk_label;
2409 	}
2410 
2411 	return NULL;
2412 }
2413 
2414 /**
2415  * smack_netlbl_add - Set the secattr on a socket
2416  * @sk: the socket
2417  *
2418  * Attach the outbound smack value (smk_out) to the socket.
2419  *
2420  * Returns 0 on success or an error code
2421  */
smack_netlbl_add(struct sock *sk)2422 static int smack_netlbl_add(struct sock *sk)
2423 {
2424 	struct socket_smack *ssp = sk->sk_security;
2425 	struct smack_known *skp = ssp->smk_out;
2426 	int rc;
2427 
2428 	local_bh_disable();
2429 	bh_lock_sock_nested(sk);
2430 
2431 	rc = netlbl_sock_setattr(sk, sk->sk_family, &skp->smk_netlabel);
2432 	switch (rc) {
2433 	case 0:
2434 		ssp->smk_state = SMK_NETLBL_LABELED;
2435 		break;
2436 	case -EDESTADDRREQ:
2437 		ssp->smk_state = SMK_NETLBL_REQSKB;
2438 		rc = 0;
2439 		break;
2440 	}
2441 
2442 	bh_unlock_sock(sk);
2443 	local_bh_enable();
2444 
2445 	return rc;
2446 }
2447 
2448 /**
2449  * smack_netlbl_delete - Remove the secattr from a socket
2450  * @sk: the socket
2451  *
2452  * Remove the outbound smack value from a socket
2453  */
smack_netlbl_delete(struct sock *sk)2454 static void smack_netlbl_delete(struct sock *sk)
2455 {
2456 	struct socket_smack *ssp = sk->sk_security;
2457 
2458 	/*
2459 	 * Take the label off the socket if one is set.
2460 	 */
2461 	if (ssp->smk_state != SMK_NETLBL_LABELED)
2462 		return;
2463 
2464 	local_bh_disable();
2465 	bh_lock_sock_nested(sk);
2466 	netlbl_sock_delattr(sk);
2467 	bh_unlock_sock(sk);
2468 	local_bh_enable();
2469 	ssp->smk_state = SMK_NETLBL_UNLABELED;
2470 }
2471 
2472 /**
2473  * smk_ipv4_check - Perform IPv4 host access checks
2474  * @sk: the socket
2475  * @sap: the destination address
2476  *
2477  * Set the correct secattr for the given socket based on the destination
2478  * address and perform any outbound access checks needed.
2479  *
2480  * Returns 0 on success or an error code.
2481  *
2482  */
smk_ipv4_check(struct sock *sk, struct sockaddr_in *sap)2483 static int smk_ipv4_check(struct sock *sk, struct sockaddr_in *sap)
2484 {
2485 	struct smack_known *skp;
2486 	int rc = 0;
2487 	struct smack_known *hkp;
2488 	struct socket_smack *ssp = sk->sk_security;
2489 	struct smk_audit_info ad;
2490 
2491 	rcu_read_lock();
2492 	hkp = smack_ipv4host_label(sap);
2493 	if (hkp != NULL) {
2494 #ifdef CONFIG_AUDIT
2495 		struct lsm_network_audit net;
2496 
2497 		smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
2498 		ad.a.u.net->family = sap->sin_family;
2499 		ad.a.u.net->dport = sap->sin_port;
2500 		ad.a.u.net->v4info.daddr = sap->sin_addr.s_addr;
2501 #endif
2502 		skp = ssp->smk_out;
2503 		rc = smk_access(skp, hkp, MAY_WRITE, &ad);
2504 		rc = smk_bu_note("IPv4 host check", skp, hkp, MAY_WRITE, rc);
2505 		/*
2506 		 * Clear the socket netlabel if it's set.
2507 		 */
2508 		if (!rc)
2509 			smack_netlbl_delete(sk);
2510 	}
2511 	rcu_read_unlock();
2512 
2513 	return rc;
2514 }
2515 
2516 /**
2517  * smk_ipv6_check - check Smack access
2518  * @subject: subject Smack label
2519  * @object: object Smack label
2520  * @address: address
2521  * @act: the action being taken
2522  *
2523  * Check an IPv6 access
2524  */
smk_ipv6_check(struct smack_known *subject, struct smack_known *object, struct sockaddr_in6 *address, int act)2525 static int smk_ipv6_check(struct smack_known *subject,
2526 				struct smack_known *object,
2527 				struct sockaddr_in6 *address, int act)
2528 {
2529 #ifdef CONFIG_AUDIT
2530 	struct lsm_network_audit net;
2531 #endif
2532 	struct smk_audit_info ad;
2533 	int rc;
2534 
2535 #ifdef CONFIG_AUDIT
2536 	smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
2537 	ad.a.u.net->family = PF_INET6;
2538 	ad.a.u.net->dport = address->sin6_port;
2539 	if (act == SMK_RECEIVING)
2540 		ad.a.u.net->v6info.saddr = address->sin6_addr;
2541 	else
2542 		ad.a.u.net->v6info.daddr = address->sin6_addr;
2543 #endif
2544 	rc = smk_access(subject, object, MAY_WRITE, &ad);
2545 	rc = smk_bu_note("IPv6 check", subject, object, MAY_WRITE, rc);
2546 	return rc;
2547 }
2548 
2549 #ifdef SMACK_IPV6_PORT_LABELING
2550 /**
2551  * smk_ipv6_port_label - Smack port access table management
2552  * @sock: socket
2553  * @address: address
2554  *
2555  * Create or update the port list entry
2556  */
smk_ipv6_port_label(struct socket *sock, struct sockaddr *address)2557 static void smk_ipv6_port_label(struct socket *sock, struct sockaddr *address)
2558 {
2559 	struct sock *sk = sock->sk;
2560 	struct sockaddr_in6 *addr6;
2561 	struct socket_smack *ssp = sock->sk->sk_security;
2562 	struct smk_port_label *spp;
2563 	unsigned short port = 0;
2564 
2565 	if (address == NULL) {
2566 		/*
2567 		 * This operation is changing the Smack information
2568 		 * on the bound socket. Take the changes to the port
2569 		 * as well.
2570 		 */
2571 		rcu_read_lock();
2572 		list_for_each_entry_rcu(spp, &smk_ipv6_port_list, list) {
2573 			if (sk != spp->smk_sock)
2574 				continue;
2575 			spp->smk_in = ssp->smk_in;
2576 			spp->smk_out = ssp->smk_out;
2577 			rcu_read_unlock();
2578 			return;
2579 		}
2580 		/*
2581 		 * A NULL address is only used for updating existing
2582 		 * bound entries. If there isn't one, it's OK.
2583 		 */
2584 		rcu_read_unlock();
2585 		return;
2586 	}
2587 
2588 	addr6 = (struct sockaddr_in6 *)address;
2589 	port = ntohs(addr6->sin6_port);
2590 	/*
2591 	 * This is a special case that is safely ignored.
2592 	 */
2593 	if (port == 0)
2594 		return;
2595 
2596 	/*
2597 	 * Look for an existing port list entry.
2598 	 * This is an indication that a port is getting reused.
2599 	 */
2600 	rcu_read_lock();
2601 	list_for_each_entry_rcu(spp, &smk_ipv6_port_list, list) {
2602 		if (spp->smk_port != port || spp->smk_sock_type != sock->type)
2603 			continue;
2604 		if (spp->smk_can_reuse != 1) {
2605 			rcu_read_unlock();
2606 			return;
2607 		}
2608 		spp->smk_port = port;
2609 		spp->smk_sock = sk;
2610 		spp->smk_in = ssp->smk_in;
2611 		spp->smk_out = ssp->smk_out;
2612 		spp->smk_can_reuse = 0;
2613 		rcu_read_unlock();
2614 		return;
2615 	}
2616 	rcu_read_unlock();
2617 	/*
2618 	 * A new port entry is required.
2619 	 */
2620 	spp = kzalloc(sizeof(*spp), GFP_KERNEL);
2621 	if (spp == NULL)
2622 		return;
2623 
2624 	spp->smk_port = port;
2625 	spp->smk_sock = sk;
2626 	spp->smk_in = ssp->smk_in;
2627 	spp->smk_out = ssp->smk_out;
2628 	spp->smk_sock_type = sock->type;
2629 	spp->smk_can_reuse = 0;
2630 
2631 	mutex_lock(&smack_ipv6_lock);
2632 	list_add_rcu(&spp->list, &smk_ipv6_port_list);
2633 	mutex_unlock(&smack_ipv6_lock);
2634 	return;
2635 }
2636 #endif
2637 
2638 /**
2639  * smk_ipv6_port_check - check Smack port access
2640  * @sk: socket
2641  * @address: address
2642  * @act: the action being taken
2643  *
2644  * Create or update the port list entry
2645  */
smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address, int act)2646 static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address,
2647 				int act)
2648 {
2649 	struct smk_port_label *spp;
2650 	struct socket_smack *ssp = sk->sk_security;
2651 	struct smack_known *skp = NULL;
2652 	unsigned short port;
2653 	struct smack_known *object;
2654 
2655 	if (act == SMK_RECEIVING) {
2656 		skp = smack_ipv6host_label(address);
2657 		object = ssp->smk_in;
2658 	} else {
2659 		skp = ssp->smk_out;
2660 		object = smack_ipv6host_label(address);
2661 	}
2662 
2663 	/*
2664 	 * The other end is a single label host.
2665 	 */
2666 	if (skp != NULL && object != NULL)
2667 		return smk_ipv6_check(skp, object, address, act);
2668 	if (skp == NULL)
2669 		skp = smack_net_ambient;
2670 	if (object == NULL)
2671 		object = smack_net_ambient;
2672 
2673 	/*
2674 	 * It's remote, so port lookup does no good.
2675 	 */
2676 	if (!smk_ipv6_localhost(address))
2677 		return smk_ipv6_check(skp, object, address, act);
2678 
2679 	/*
2680 	 * It's local so the send check has to have passed.
2681 	 */
2682 	if (act == SMK_RECEIVING)
2683 		return 0;
2684 
2685 	port = ntohs(address->sin6_port);
2686 	rcu_read_lock();
2687 	list_for_each_entry_rcu(spp, &smk_ipv6_port_list, list) {
2688 		if (spp->smk_port != port || spp->smk_sock_type != sk->sk_type)
2689 			continue;
2690 		object = spp->smk_in;
2691 		if (act == SMK_CONNECTING)
2692 			ssp->smk_packet = spp->smk_out;
2693 		break;
2694 	}
2695 	rcu_read_unlock();
2696 
2697 	return smk_ipv6_check(skp, object, address, act);
2698 }
2699 
2700 /**
2701  * smack_inode_setsecurity - set smack xattrs
2702  * @inode: the object
2703  * @name: attribute name
2704  * @value: attribute value
2705  * @size: size of the attribute
2706  * @flags: unused
2707  *
2708  * Sets the named attribute in the appropriate blob
2709  *
2710  * Returns 0 on success, or an error code
2711  */
smack_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags)2712 static int smack_inode_setsecurity(struct inode *inode, const char *name,
2713 				   const void *value, size_t size, int flags)
2714 {
2715 	struct smack_known *skp;
2716 	struct inode_smack *nsp = smack_inode(inode);
2717 	struct socket_smack *ssp;
2718 	struct socket *sock;
2719 	int rc = 0;
2720 
2721 	if (value == NULL || size > SMK_LONGLABEL || size == 0)
2722 		return -EINVAL;
2723 
2724 	skp = smk_import_entry(value, size);
2725 	if (IS_ERR(skp))
2726 		return PTR_ERR(skp);
2727 
2728 	if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
2729 		nsp->smk_inode = skp;
2730 		nsp->smk_flags |= SMK_INODE_INSTANT;
2731 		return 0;
2732 	}
2733 	/*
2734 	 * The rest of the Smack xattrs are only on sockets.
2735 	 */
2736 	if (inode->i_sb->s_magic != SOCKFS_MAGIC)
2737 		return -EOPNOTSUPP;
2738 
2739 	sock = SOCKET_I(inode);
2740 	if (sock == NULL || sock->sk == NULL)
2741 		return -EOPNOTSUPP;
2742 
2743 	ssp = sock->sk->sk_security;
2744 
2745 	if (strcmp(name, XATTR_SMACK_IPIN) == 0)
2746 		ssp->smk_in = skp;
2747 	else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) {
2748 		ssp->smk_out = skp;
2749 		if (sock->sk->sk_family == PF_INET) {
2750 			rc = smack_netlbl_add(sock->sk);
2751 			if (rc != 0)
2752 				printk(KERN_WARNING
2753 					"Smack: \"%s\" netlbl error %d.\n",
2754 					__func__, -rc);
2755 		}
2756 	} else
2757 		return -EOPNOTSUPP;
2758 
2759 #ifdef SMACK_IPV6_PORT_LABELING
2760 	if (sock->sk->sk_family == PF_INET6)
2761 		smk_ipv6_port_label(sock, NULL);
2762 #endif
2763 
2764 	return 0;
2765 }
2766 
2767 /**
2768  * smack_socket_post_create - finish socket setup
2769  * @sock: the socket
2770  * @family: protocol family
2771  * @type: unused
2772  * @protocol: unused
2773  * @kern: unused
2774  *
2775  * Sets the netlabel information on the socket
2776  *
2777  * Returns 0 on success, and error code otherwise
2778  */
smack_socket_post_create(struct socket *sock, int family, int type, int protocol, int kern)2779 static int smack_socket_post_create(struct socket *sock, int family,
2780 				    int type, int protocol, int kern)
2781 {
2782 	struct socket_smack *ssp;
2783 
2784 	if (sock->sk == NULL)
2785 		return 0;
2786 
2787 	/*
2788 	 * Sockets created by kernel threads receive web label.
2789 	 */
2790 	if (unlikely(current->flags & PF_KTHREAD)) {
2791 		ssp = sock->sk->sk_security;
2792 		ssp->smk_in = &smack_known_web;
2793 		ssp->smk_out = &smack_known_web;
2794 	}
2795 
2796 	if (family != PF_INET)
2797 		return 0;
2798 	/*
2799 	 * Set the outbound netlbl.
2800 	 */
2801 	return smack_netlbl_add(sock->sk);
2802 }
2803 
2804 /**
2805  * smack_socket_socketpair - create socket pair
2806  * @socka: one socket
2807  * @sockb: another socket
2808  *
2809  * Cross reference the peer labels for SO_PEERSEC
2810  *
2811  * Returns 0
2812  */
smack_socket_socketpair(struct socket *socka, struct socket *sockb)2813 static int smack_socket_socketpair(struct socket *socka,
2814 		                   struct socket *sockb)
2815 {
2816 	struct socket_smack *asp = socka->sk->sk_security;
2817 	struct socket_smack *bsp = sockb->sk->sk_security;
2818 
2819 	asp->smk_packet = bsp->smk_out;
2820 	bsp->smk_packet = asp->smk_out;
2821 
2822 	return 0;
2823 }
2824 
2825 #ifdef SMACK_IPV6_PORT_LABELING
2826 /**
2827  * smack_socket_bind - record port binding information.
2828  * @sock: the socket
2829  * @address: the port address
2830  * @addrlen: size of the address
2831  *
2832  * Records the label bound to a port.
2833  *
2834  * Returns 0 on success, and error code otherwise
2835  */
smack_socket_bind(struct socket *sock, struct sockaddr *address, int addrlen)2836 static int smack_socket_bind(struct socket *sock, struct sockaddr *address,
2837 				int addrlen)
2838 {
2839 	if (sock->sk != NULL && sock->sk->sk_family == PF_INET6) {
2840 		if (addrlen < SIN6_LEN_RFC2133 ||
2841 		    address->sa_family != AF_INET6)
2842 			return -EINVAL;
2843 		smk_ipv6_port_label(sock, address);
2844 	}
2845 	return 0;
2846 }
2847 #endif /* SMACK_IPV6_PORT_LABELING */
2848 
2849 /**
2850  * smack_socket_connect - connect access check
2851  * @sock: the socket
2852  * @sap: the other end
2853  * @addrlen: size of sap
2854  *
2855  * Verifies that a connection may be possible
2856  *
2857  * Returns 0 on success, and error code otherwise
2858  */
smack_socket_connect(struct socket *sock, struct sockaddr *sap, int addrlen)2859 static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
2860 				int addrlen)
2861 {
2862 	int rc = 0;
2863 
2864 	if (sock->sk == NULL)
2865 		return 0;
2866 	if (sock->sk->sk_family != PF_INET &&
2867 	    (!IS_ENABLED(CONFIG_IPV6) || sock->sk->sk_family != PF_INET6))
2868 		return 0;
2869 	if (addrlen < offsetofend(struct sockaddr, sa_family))
2870 		return 0;
2871 	if (IS_ENABLED(CONFIG_IPV6) && sap->sa_family == AF_INET6) {
2872 		struct sockaddr_in6 *sip = (struct sockaddr_in6 *)sap;
2873 		struct smack_known *rsp = NULL;
2874 
2875 		if (addrlen < SIN6_LEN_RFC2133)
2876 			return 0;
2877 		if (__is_defined(SMACK_IPV6_SECMARK_LABELING))
2878 			rsp = smack_ipv6host_label(sip);
2879 		if (rsp != NULL) {
2880 			struct socket_smack *ssp = sock->sk->sk_security;
2881 
2882 			rc = smk_ipv6_check(ssp->smk_out, rsp, sip,
2883 					    SMK_CONNECTING);
2884 		}
2885 		if (__is_defined(SMACK_IPV6_PORT_LABELING))
2886 			rc = smk_ipv6_port_check(sock->sk, sip, SMK_CONNECTING);
2887 
2888 		return rc;
2889 	}
2890 	if (sap->sa_family != AF_INET || addrlen < sizeof(struct sockaddr_in))
2891 		return 0;
2892 	rc = smk_ipv4_check(sock->sk, (struct sockaddr_in *)sap);
2893 	return rc;
2894 }
2895 
2896 /**
2897  * smack_flags_to_may - convert S_ to MAY_ values
2898  * @flags: the S_ value
2899  *
2900  * Returns the equivalent MAY_ value
2901  */
smack_flags_to_may(int flags)2902 static int smack_flags_to_may(int flags)
2903 {
2904 	int may = 0;
2905 
2906 	if (flags & S_IRUGO)
2907 		may |= MAY_READ;
2908 	if (flags & S_IWUGO)
2909 		may |= MAY_WRITE;
2910 	if (flags & S_IXUGO)
2911 		may |= MAY_EXEC;
2912 
2913 	return may;
2914 }
2915 
2916 /**
2917  * smack_msg_msg_alloc_security - Set the security blob for msg_msg
2918  * @msg: the object
2919  *
2920  * Returns 0
2921  */
smack_msg_msg_alloc_security(struct msg_msg *msg)2922 static int smack_msg_msg_alloc_security(struct msg_msg *msg)
2923 {
2924 	struct smack_known **blob = smack_msg_msg(msg);
2925 
2926 	*blob = smk_of_current();
2927 	return 0;
2928 }
2929 
2930 /**
2931  * smack_of_ipc - the smack pointer for the ipc
2932  * @isp: the object
2933  *
2934  * Returns a pointer to the smack value
2935  */
smack_of_ipc(struct kern_ipc_perm *isp)2936 static struct smack_known *smack_of_ipc(struct kern_ipc_perm *isp)
2937 {
2938 	struct smack_known **blob = smack_ipc(isp);
2939 
2940 	return *blob;
2941 }
2942 
2943 /**
2944  * smack_ipc_alloc_security - Set the security blob for ipc
2945  * @isp: the object
2946  *
2947  * Returns 0
2948  */
smack_ipc_alloc_security(struct kern_ipc_perm *isp)2949 static int smack_ipc_alloc_security(struct kern_ipc_perm *isp)
2950 {
2951 	struct smack_known **blob = smack_ipc(isp);
2952 
2953 	*blob = smk_of_current();
2954 	return 0;
2955 }
2956 
2957 /**
2958  * smk_curacc_shm : check if current has access on shm
2959  * @isp : the object
2960  * @access : access requested
2961  *
2962  * Returns 0 if current has the requested access, error code otherwise
2963  */
smk_curacc_shm(struct kern_ipc_perm *isp, int access)2964 static int smk_curacc_shm(struct kern_ipc_perm *isp, int access)
2965 {
2966 	struct smack_known *ssp = smack_of_ipc(isp);
2967 	struct smk_audit_info ad;
2968 	int rc;
2969 
2970 #ifdef CONFIG_AUDIT
2971 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
2972 	ad.a.u.ipc_id = isp->id;
2973 #endif
2974 	rc = smk_curacc(ssp, access, &ad);
2975 	rc = smk_bu_current("shm", ssp, access, rc);
2976 	return rc;
2977 }
2978 
2979 /**
2980  * smack_shm_associate - Smack access check for shm
2981  * @isp: the object
2982  * @shmflg: access requested
2983  *
2984  * Returns 0 if current has the requested access, error code otherwise
2985  */
smack_shm_associate(struct kern_ipc_perm *isp, int shmflg)2986 static int smack_shm_associate(struct kern_ipc_perm *isp, int shmflg)
2987 {
2988 	int may;
2989 
2990 	may = smack_flags_to_may(shmflg);
2991 	return smk_curacc_shm(isp, may);
2992 }
2993 
2994 /**
2995  * smack_shm_shmctl - Smack access check for shm
2996  * @isp: the object
2997  * @cmd: what it wants to do
2998  *
2999  * Returns 0 if current has the requested access, error code otherwise
3000  */
smack_shm_shmctl(struct kern_ipc_perm *isp, int cmd)3001 static int smack_shm_shmctl(struct kern_ipc_perm *isp, int cmd)
3002 {
3003 	int may;
3004 
3005 	switch (cmd) {
3006 	case IPC_STAT:
3007 	case SHM_STAT:
3008 	case SHM_STAT_ANY:
3009 		may = MAY_READ;
3010 		break;
3011 	case IPC_SET:
3012 	case SHM_LOCK:
3013 	case SHM_UNLOCK:
3014 	case IPC_RMID:
3015 		may = MAY_READWRITE;
3016 		break;
3017 	case IPC_INFO:
3018 	case SHM_INFO:
3019 		/*
3020 		 * System level information.
3021 		 */
3022 		return 0;
3023 	default:
3024 		return -EINVAL;
3025 	}
3026 	return smk_curacc_shm(isp, may);
3027 }
3028 
3029 /**
3030  * smack_shm_shmat - Smack access for shmat
3031  * @isp: the object
3032  * @shmaddr: unused
3033  * @shmflg: access requested
3034  *
3035  * Returns 0 if current has the requested access, error code otherwise
3036  */
smack_shm_shmat(struct kern_ipc_perm *isp, char __user *shmaddr, int shmflg)3037 static int smack_shm_shmat(struct kern_ipc_perm *isp, char __user *shmaddr,
3038 			   int shmflg)
3039 {
3040 	int may;
3041 
3042 	may = smack_flags_to_may(shmflg);
3043 	return smk_curacc_shm(isp, may);
3044 }
3045 
3046 /**
3047  * smk_curacc_sem : check if current has access on sem
3048  * @isp : the object
3049  * @access : access requested
3050  *
3051  * Returns 0 if current has the requested access, error code otherwise
3052  */
smk_curacc_sem(struct kern_ipc_perm *isp, int access)3053 static int smk_curacc_sem(struct kern_ipc_perm *isp, int access)
3054 {
3055 	struct smack_known *ssp = smack_of_ipc(isp);
3056 	struct smk_audit_info ad;
3057 	int rc;
3058 
3059 #ifdef CONFIG_AUDIT
3060 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
3061 	ad.a.u.ipc_id = isp->id;
3062 #endif
3063 	rc = smk_curacc(ssp, access, &ad);
3064 	rc = smk_bu_current("sem", ssp, access, rc);
3065 	return rc;
3066 }
3067 
3068 /**
3069  * smack_sem_associate - Smack access check for sem
3070  * @isp: the object
3071  * @semflg: access requested
3072  *
3073  * Returns 0 if current has the requested access, error code otherwise
3074  */
smack_sem_associate(struct kern_ipc_perm *isp, int semflg)3075 static int smack_sem_associate(struct kern_ipc_perm *isp, int semflg)
3076 {
3077 	int may;
3078 
3079 	may = smack_flags_to_may(semflg);
3080 	return smk_curacc_sem(isp, may);
3081 }
3082 
3083 /**
3084  * smack_sem_shmctl - Smack access check for sem
3085  * @isp: the object
3086  * @cmd: what it wants to do
3087  *
3088  * Returns 0 if current has the requested access, error code otherwise
3089  */
smack_sem_semctl(struct kern_ipc_perm *isp, int cmd)3090 static int smack_sem_semctl(struct kern_ipc_perm *isp, int cmd)
3091 {
3092 	int may;
3093 
3094 	switch (cmd) {
3095 	case GETPID:
3096 	case GETNCNT:
3097 	case GETZCNT:
3098 	case GETVAL:
3099 	case GETALL:
3100 	case IPC_STAT:
3101 	case SEM_STAT:
3102 	case SEM_STAT_ANY:
3103 		may = MAY_READ;
3104 		break;
3105 	case SETVAL:
3106 	case SETALL:
3107 	case IPC_RMID:
3108 	case IPC_SET:
3109 		may = MAY_READWRITE;
3110 		break;
3111 	case IPC_INFO:
3112 	case SEM_INFO:
3113 		/*
3114 		 * System level information
3115 		 */
3116 		return 0;
3117 	default:
3118 		return -EINVAL;
3119 	}
3120 
3121 	return smk_curacc_sem(isp, may);
3122 }
3123 
3124 /**
3125  * smack_sem_semop - Smack checks of semaphore operations
3126  * @isp: the object
3127  * @sops: unused
3128  * @nsops: unused
3129  * @alter: unused
3130  *
3131  * Treated as read and write in all cases.
3132  *
3133  * Returns 0 if access is allowed, error code otherwise
3134  */
smack_sem_semop(struct kern_ipc_perm *isp, struct sembuf *sops, unsigned nsops, int alter)3135 static int smack_sem_semop(struct kern_ipc_perm *isp, struct sembuf *sops,
3136 			   unsigned nsops, int alter)
3137 {
3138 	return smk_curacc_sem(isp, MAY_READWRITE);
3139 }
3140 
3141 /**
3142  * smk_curacc_msq : helper to check if current has access on msq
3143  * @isp : the msq
3144  * @access : access requested
3145  *
3146  * return 0 if current has access, error otherwise
3147  */
smk_curacc_msq(struct kern_ipc_perm *isp, int access)3148 static int smk_curacc_msq(struct kern_ipc_perm *isp, int access)
3149 {
3150 	struct smack_known *msp = smack_of_ipc(isp);
3151 	struct smk_audit_info ad;
3152 	int rc;
3153 
3154 #ifdef CONFIG_AUDIT
3155 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
3156 	ad.a.u.ipc_id = isp->id;
3157 #endif
3158 	rc = smk_curacc(msp, access, &ad);
3159 	rc = smk_bu_current("msq", msp, access, rc);
3160 	return rc;
3161 }
3162 
3163 /**
3164  * smack_msg_queue_associate - Smack access check for msg_queue
3165  * @isp: the object
3166  * @msqflg: access requested
3167  *
3168  * Returns 0 if current has the requested access, error code otherwise
3169  */
smack_msg_queue_associate(struct kern_ipc_perm *isp, int msqflg)3170 static int smack_msg_queue_associate(struct kern_ipc_perm *isp, int msqflg)
3171 {
3172 	int may;
3173 
3174 	may = smack_flags_to_may(msqflg);
3175 	return smk_curacc_msq(isp, may);
3176 }
3177 
3178 /**
3179  * smack_msg_queue_msgctl - Smack access check for msg_queue
3180  * @isp: the object
3181  * @cmd: what it wants to do
3182  *
3183  * Returns 0 if current has the requested access, error code otherwise
3184  */
smack_msg_queue_msgctl(struct kern_ipc_perm *isp, int cmd)3185 static int smack_msg_queue_msgctl(struct kern_ipc_perm *isp, int cmd)
3186 {
3187 	int may;
3188 
3189 	switch (cmd) {
3190 	case IPC_STAT:
3191 	case MSG_STAT:
3192 	case MSG_STAT_ANY:
3193 		may = MAY_READ;
3194 		break;
3195 	case IPC_SET:
3196 	case IPC_RMID:
3197 		may = MAY_READWRITE;
3198 		break;
3199 	case IPC_INFO:
3200 	case MSG_INFO:
3201 		/*
3202 		 * System level information
3203 		 */
3204 		return 0;
3205 	default:
3206 		return -EINVAL;
3207 	}
3208 
3209 	return smk_curacc_msq(isp, may);
3210 }
3211 
3212 /**
3213  * smack_msg_queue_msgsnd - Smack access check for msg_queue
3214  * @isp: the object
3215  * @msg: unused
3216  * @msqflg: access requested
3217  *
3218  * Returns 0 if current has the requested access, error code otherwise
3219  */
smack_msg_queue_msgsnd(struct kern_ipc_perm *isp, struct msg_msg *msg, int msqflg)3220 static int smack_msg_queue_msgsnd(struct kern_ipc_perm *isp, struct msg_msg *msg,
3221 				  int msqflg)
3222 {
3223 	int may;
3224 
3225 	may = smack_flags_to_may(msqflg);
3226 	return smk_curacc_msq(isp, may);
3227 }
3228 
3229 /**
3230  * smack_msg_queue_msgsnd - Smack access check for msg_queue
3231  * @isp: the object
3232  * @msg: unused
3233  * @target: unused
3234  * @type: unused
3235  * @mode: unused
3236  *
3237  * Returns 0 if current has read and write access, error code otherwise
3238  */
smack_msg_queue_msgrcv(struct kern_ipc_perm *isp, struct msg_msg *msg, struct task_struct *target, long type, int mode)3239 static int smack_msg_queue_msgrcv(struct kern_ipc_perm *isp, struct msg_msg *msg,
3240 			struct task_struct *target, long type, int mode)
3241 {
3242 	return smk_curacc_msq(isp, MAY_READWRITE);
3243 }
3244 
3245 /**
3246  * smack_ipc_permission - Smack access for ipc_permission()
3247  * @ipp: the object permissions
3248  * @flag: access requested
3249  *
3250  * Returns 0 if current has read and write access, error code otherwise
3251  */
smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)3252 static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
3253 {
3254 	struct smack_known **blob = smack_ipc(ipp);
3255 	struct smack_known *iskp = *blob;
3256 	int may = smack_flags_to_may(flag);
3257 	struct smk_audit_info ad;
3258 	int rc;
3259 
3260 #ifdef CONFIG_AUDIT
3261 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
3262 	ad.a.u.ipc_id = ipp->id;
3263 #endif
3264 	rc = smk_curacc(iskp, may, &ad);
3265 	rc = smk_bu_current("svipc", iskp, may, rc);
3266 	return rc;
3267 }
3268 
3269 /**
3270  * smack_ipc_getsecid - Extract smack security id
3271  * @ipp: the object permissions
3272  * @secid: where result will be saved
3273  */
smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid)3274 static void smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid)
3275 {
3276 	struct smack_known **blob = smack_ipc(ipp);
3277 	struct smack_known *iskp = *blob;
3278 
3279 	*secid = iskp->smk_secid;
3280 }
3281 
3282 /**
3283  * smack_d_instantiate - Make sure the blob is correct on an inode
3284  * @opt_dentry: dentry where inode will be attached
3285  * @inode: the object
3286  *
3287  * Set the inode's security blob if it hasn't been done already.
3288  */
smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)3289 static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
3290 {
3291 	struct super_block *sbp;
3292 	struct superblock_smack *sbsp;
3293 	struct inode_smack *isp;
3294 	struct smack_known *skp;
3295 	struct smack_known *ckp = smk_of_current();
3296 	struct smack_known *final;
3297 	char trattr[TRANS_TRUE_SIZE];
3298 	int transflag = 0;
3299 	int rc;
3300 	struct dentry *dp;
3301 
3302 	if (inode == NULL)
3303 		return;
3304 
3305 	isp = smack_inode(inode);
3306 
3307 	/*
3308 	 * If the inode is already instantiated
3309 	 * take the quick way out
3310 	 */
3311 	if (isp->smk_flags & SMK_INODE_INSTANT)
3312 		return;
3313 
3314 	sbp = inode->i_sb;
3315 	sbsp = sbp->s_security;
3316 	/*
3317 	 * We're going to use the superblock default label
3318 	 * if there's no label on the file.
3319 	 */
3320 	final = sbsp->smk_default;
3321 
3322 	/*
3323 	 * If this is the root inode the superblock
3324 	 * may be in the process of initialization.
3325 	 * If that is the case use the root value out
3326 	 * of the superblock.
3327 	 */
3328 	if (opt_dentry->d_parent == opt_dentry) {
3329 		switch (sbp->s_magic) {
3330 		case CGROUP_SUPER_MAGIC:
3331 		case CGROUP2_SUPER_MAGIC:
3332 			/*
3333 			 * The cgroup filesystem is never mounted,
3334 			 * so there's no opportunity to set the mount
3335 			 * options.
3336 			 */
3337 			sbsp->smk_root = &smack_known_star;
3338 			sbsp->smk_default = &smack_known_star;
3339 			isp->smk_inode = sbsp->smk_root;
3340 			break;
3341 		case TMPFS_MAGIC:
3342 			/*
3343 			 * What about shmem/tmpfs anonymous files with dentry
3344 			 * obtained from d_alloc_pseudo()?
3345 			 */
3346 			isp->smk_inode = smk_of_current();
3347 			break;
3348 		case PIPEFS_MAGIC:
3349 			isp->smk_inode = smk_of_current();
3350 			break;
3351 		case SOCKFS_MAGIC:
3352 			/*
3353 			 * Socket access is controlled by the socket
3354 			 * structures associated with the task involved.
3355 			 */
3356 			isp->smk_inode = &smack_known_star;
3357 			break;
3358 		default:
3359 			isp->smk_inode = sbsp->smk_root;
3360 			break;
3361 		}
3362 		isp->smk_flags |= SMK_INODE_INSTANT;
3363 		return;
3364 	}
3365 
3366 	/*
3367 	 * This is pretty hackish.
3368 	 * Casey says that we shouldn't have to do
3369 	 * file system specific code, but it does help
3370 	 * with keeping it simple.
3371 	 */
3372 	switch (sbp->s_magic) {
3373 	case SMACK_MAGIC:
3374 	case CGROUP_SUPER_MAGIC:
3375 	case CGROUP2_SUPER_MAGIC:
3376 		/*
3377 		 * Casey says that it's a little embarrassing
3378 		 * that the smack file system doesn't do
3379 		 * extended attributes.
3380 		 *
3381 		 * Cgroupfs is special
3382 		 */
3383 		final = &smack_known_star;
3384 		break;
3385 	case DEVPTS_SUPER_MAGIC:
3386 		/*
3387 		 * devpts seems content with the label of the task.
3388 		 * Programs that change smack have to treat the
3389 		 * pty with respect.
3390 		 */
3391 		final = ckp;
3392 		break;
3393 	case PROC_SUPER_MAGIC:
3394 		/*
3395 		 * Casey says procfs appears not to care.
3396 		 * The superblock default suffices.
3397 		 */
3398 		break;
3399 	case TMPFS_MAGIC:
3400 		/*
3401 		 * Device labels should come from the filesystem,
3402 		 * but watch out, because they're volitile,
3403 		 * getting recreated on every reboot.
3404 		 */
3405 		final = &smack_known_star;
3406 		/*
3407 		 * If a smack value has been set we want to use it,
3408 		 * but since tmpfs isn't giving us the opportunity
3409 		 * to set mount options simulate setting the
3410 		 * superblock default.
3411 		 */
3412 		fallthrough;
3413 	default:
3414 		/*
3415 		 * This isn't an understood special case.
3416 		 * Get the value from the xattr.
3417 		 */
3418 
3419 		/*
3420 		 * UNIX domain sockets use lower level socket data.
3421 		 */
3422 		if (S_ISSOCK(inode->i_mode)) {
3423 			final = &smack_known_star;
3424 			break;
3425 		}
3426 		/*
3427 		 * No xattr support means, alas, no SMACK label.
3428 		 * Use the aforeapplied default.
3429 		 * It would be curious if the label of the task
3430 		 * does not match that assigned.
3431 		 */
3432 		if (!(inode->i_opflags & IOP_XATTR))
3433 		        break;
3434 		/*
3435 		 * Get the dentry for xattr.
3436 		 */
3437 		dp = dget(opt_dentry);
3438 		skp = smk_fetch(XATTR_NAME_SMACK, inode, dp);
3439 		if (!IS_ERR_OR_NULL(skp))
3440 			final = skp;
3441 
3442 		/*
3443 		 * Transmuting directory
3444 		 */
3445 		if (S_ISDIR(inode->i_mode)) {
3446 			/*
3447 			 * If this is a new directory and the label was
3448 			 * transmuted when the inode was initialized
3449 			 * set the transmute attribute on the directory
3450 			 * and mark the inode.
3451 			 *
3452 			 * If there is a transmute attribute on the
3453 			 * directory mark the inode.
3454 			 */
3455 			if (isp->smk_flags & SMK_INODE_CHANGED) {
3456 				isp->smk_flags &= ~SMK_INODE_CHANGED;
3457 				rc = __vfs_setxattr(dp, inode,
3458 					XATTR_NAME_SMACKTRANSMUTE,
3459 					TRANS_TRUE, TRANS_TRUE_SIZE,
3460 					0);
3461 			} else {
3462 				rc = __vfs_getxattr(dp, inode,
3463 					XATTR_NAME_SMACKTRANSMUTE, trattr,
3464 					TRANS_TRUE_SIZE);
3465 				if (rc >= 0 && strncmp(trattr, TRANS_TRUE,
3466 						       TRANS_TRUE_SIZE) != 0)
3467 					rc = -EINVAL;
3468 			}
3469 			if (rc >= 0)
3470 				transflag = SMK_INODE_TRANSMUTE;
3471 		}
3472 		/*
3473 		 * Don't let the exec or mmap label be "*" or "@".
3474 		 */
3475 		skp = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp);
3476 		if (IS_ERR(skp) || skp == &smack_known_star ||
3477 		    skp == &smack_known_web)
3478 			skp = NULL;
3479 		isp->smk_task = skp;
3480 
3481 		skp = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp);
3482 		if (IS_ERR(skp) || skp == &smack_known_star ||
3483 		    skp == &smack_known_web)
3484 			skp = NULL;
3485 		isp->smk_mmap = skp;
3486 
3487 		dput(dp);
3488 		break;
3489 	}
3490 
3491 	if (final == NULL)
3492 		isp->smk_inode = ckp;
3493 	else
3494 		isp->smk_inode = final;
3495 
3496 	isp->smk_flags |= (SMK_INODE_INSTANT | transflag);
3497 
3498 	return;
3499 }
3500 
3501 /**
3502  * smack_getprocattr - Smack process attribute access
3503  * @p: the object task
3504  * @name: the name of the attribute in /proc/.../attr
3505  * @value: where to put the result
3506  *
3507  * Places a copy of the task Smack into value
3508  *
3509  * Returns the length of the smack label or an error code
3510  */
smack_getprocattr(struct task_struct *p, char *name, char **value)3511 static int smack_getprocattr(struct task_struct *p, char *name, char **value)
3512 {
3513 	struct smack_known *skp = smk_of_task_struct(p);
3514 	char *cp;
3515 	int slen;
3516 
3517 	if (strcmp(name, "current") != 0)
3518 		return -EINVAL;
3519 
3520 	cp = kstrdup(skp->smk_known, GFP_KERNEL);
3521 	if (cp == NULL)
3522 		return -ENOMEM;
3523 
3524 	slen = strlen(cp);
3525 	*value = cp;
3526 	return slen;
3527 }
3528 
3529 /**
3530  * smack_setprocattr - Smack process attribute setting
3531  * @name: the name of the attribute in /proc/.../attr
3532  * @value: the value to set
3533  * @size: the size of the value
3534  *
3535  * Sets the Smack value of the task. Only setting self
3536  * is permitted and only with privilege
3537  *
3538  * Returns the length of the smack label or an error code
3539  */
smack_setprocattr(const char *name, void *value, size_t size)3540 static int smack_setprocattr(const char *name, void *value, size_t size)
3541 {
3542 	struct task_smack *tsp = smack_cred(current_cred());
3543 	struct cred *new;
3544 	struct smack_known *skp;
3545 	struct smack_known_list_elem *sklep;
3546 	int rc;
3547 
3548 	if (!smack_privileged(CAP_MAC_ADMIN) && list_empty(&tsp->smk_relabel))
3549 		return -EPERM;
3550 
3551 	if (value == NULL || size == 0 || size >= SMK_LONGLABEL)
3552 		return -EINVAL;
3553 
3554 	if (strcmp(name, "current") != 0)
3555 		return -EINVAL;
3556 
3557 	skp = smk_import_entry(value, size);
3558 	if (IS_ERR(skp))
3559 		return PTR_ERR(skp);
3560 
3561 	/*
3562 	 * No process is ever allowed the web ("@") label
3563 	 * and the star ("*") label.
3564 	 */
3565 	if (skp == &smack_known_web || skp == &smack_known_star)
3566 		return -EINVAL;
3567 
3568 	if (!smack_privileged(CAP_MAC_ADMIN)) {
3569 		rc = -EPERM;
3570 		list_for_each_entry(sklep, &tsp->smk_relabel, list)
3571 			if (sklep->smk_label == skp) {
3572 				rc = 0;
3573 				break;
3574 			}
3575 		if (rc)
3576 			return rc;
3577 	}
3578 
3579 	new = prepare_creds();
3580 	if (new == NULL)
3581 		return -ENOMEM;
3582 
3583 	tsp = smack_cred(new);
3584 	tsp->smk_task = skp;
3585 	/*
3586 	 * process can change its label only once
3587 	 */
3588 	smk_destroy_label_list(&tsp->smk_relabel);
3589 
3590 	commit_creds(new);
3591 	return size;
3592 }
3593 
3594 /**
3595  * smack_unix_stream_connect - Smack access on UDS
3596  * @sock: one sock
3597  * @other: the other sock
3598  * @newsk: unused
3599  *
3600  * Return 0 if a subject with the smack of sock could access
3601  * an object with the smack of other, otherwise an error code
3602  */
smack_unix_stream_connect(struct sock *sock, struct sock *other, struct sock *newsk)3603 static int smack_unix_stream_connect(struct sock *sock,
3604 				     struct sock *other, struct sock *newsk)
3605 {
3606 	struct smack_known *skp;
3607 	struct smack_known *okp;
3608 	struct socket_smack *ssp = sock->sk_security;
3609 	struct socket_smack *osp = other->sk_security;
3610 	struct socket_smack *nsp = newsk->sk_security;
3611 	struct smk_audit_info ad;
3612 	int rc = 0;
3613 #ifdef CONFIG_AUDIT
3614 	struct lsm_network_audit net;
3615 #endif
3616 
3617 	if (!smack_privileged(CAP_MAC_OVERRIDE)) {
3618 		skp = ssp->smk_out;
3619 		okp = osp->smk_in;
3620 #ifdef CONFIG_AUDIT
3621 		smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
3622 		smk_ad_setfield_u_net_sk(&ad, other);
3623 #endif
3624 		rc = smk_access(skp, okp, MAY_WRITE, &ad);
3625 		rc = smk_bu_note("UDS connect", skp, okp, MAY_WRITE, rc);
3626 		if (rc == 0) {
3627 			okp = osp->smk_out;
3628 			skp = ssp->smk_in;
3629 			rc = smk_access(okp, skp, MAY_WRITE, &ad);
3630 			rc = smk_bu_note("UDS connect", okp, skp,
3631 						MAY_WRITE, rc);
3632 		}
3633 	}
3634 
3635 	/*
3636 	 * Cross reference the peer labels for SO_PEERSEC.
3637 	 */
3638 	if (rc == 0) {
3639 		nsp->smk_packet = ssp->smk_out;
3640 		ssp->smk_packet = osp->smk_out;
3641 	}
3642 
3643 	return rc;
3644 }
3645 
3646 /**
3647  * smack_unix_may_send - Smack access on UDS
3648  * @sock: one socket
3649  * @other: the other socket
3650  *
3651  * Return 0 if a subject with the smack of sock could access
3652  * an object with the smack of other, otherwise an error code
3653  */
smack_unix_may_send(struct socket *sock, struct socket *other)3654 static int smack_unix_may_send(struct socket *sock, struct socket *other)
3655 {
3656 	struct socket_smack *ssp = sock->sk->sk_security;
3657 	struct socket_smack *osp = other->sk->sk_security;
3658 	struct smk_audit_info ad;
3659 	int rc;
3660 
3661 #ifdef CONFIG_AUDIT
3662 	struct lsm_network_audit net;
3663 
3664 	smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
3665 	smk_ad_setfield_u_net_sk(&ad, other->sk);
3666 #endif
3667 
3668 	if (smack_privileged(CAP_MAC_OVERRIDE))
3669 		return 0;
3670 
3671 	rc = smk_access(ssp->smk_out, osp->smk_in, MAY_WRITE, &ad);
3672 	rc = smk_bu_note("UDS send", ssp->smk_out, osp->smk_in, MAY_WRITE, rc);
3673 	return rc;
3674 }
3675 
3676 /**
3677  * smack_socket_sendmsg - Smack check based on destination host
3678  * @sock: the socket
3679  * @msg: the message
3680  * @size: the size of the message
3681  *
3682  * Return 0 if the current subject can write to the destination host.
3683  * For IPv4 this is only a question if the destination is a single label host.
3684  * For IPv6 this is a check against the label of the port.
3685  */
smack_socket_sendmsg(struct socket *sock, struct msghdr *msg, int size)3686 static int smack_socket_sendmsg(struct socket *sock, struct msghdr *msg,
3687 				int size)
3688 {
3689 	struct sockaddr_in *sip = (struct sockaddr_in *) msg->msg_name;
3690 #if IS_ENABLED(CONFIG_IPV6)
3691 	struct sockaddr_in6 *sap = (struct sockaddr_in6 *) msg->msg_name;
3692 #endif
3693 #ifdef SMACK_IPV6_SECMARK_LABELING
3694 	struct socket_smack *ssp = sock->sk->sk_security;
3695 	struct smack_known *rsp;
3696 #endif
3697 	int rc = 0;
3698 
3699 	/*
3700 	 * Perfectly reasonable for this to be NULL
3701 	 */
3702 	if (sip == NULL)
3703 		return 0;
3704 
3705 	switch (sock->sk->sk_family) {
3706 	case AF_INET:
3707 		if (msg->msg_namelen < sizeof(struct sockaddr_in) ||
3708 		    sip->sin_family != AF_INET)
3709 			return -EINVAL;
3710 		rc = smk_ipv4_check(sock->sk, sip);
3711 		break;
3712 #if IS_ENABLED(CONFIG_IPV6)
3713 	case AF_INET6:
3714 		if (msg->msg_namelen < SIN6_LEN_RFC2133 ||
3715 		    sap->sin6_family != AF_INET6)
3716 			return -EINVAL;
3717 #ifdef SMACK_IPV6_SECMARK_LABELING
3718 		rsp = smack_ipv6host_label(sap);
3719 		if (rsp != NULL)
3720 			rc = smk_ipv6_check(ssp->smk_out, rsp, sap,
3721 						SMK_CONNECTING);
3722 #endif
3723 #ifdef SMACK_IPV6_PORT_LABELING
3724 		rc = smk_ipv6_port_check(sock->sk, sap, SMK_SENDING);
3725 #endif
3726 #endif /* IS_ENABLED(CONFIG_IPV6) */
3727 		break;
3728 	}
3729 	return rc;
3730 }
3731 
3732 /**
3733  * smack_from_secattr - Convert a netlabel attr.mls.lvl/attr.mls.cat pair to smack
3734  * @sap: netlabel secattr
3735  * @ssp: socket security information
3736  *
3737  * Returns a pointer to a Smack label entry found on the label list.
3738  */
smack_from_secattr(struct netlbl_lsm_secattr *sap, struct socket_smack *ssp)3739 static struct smack_known *smack_from_secattr(struct netlbl_lsm_secattr *sap,
3740 						struct socket_smack *ssp)
3741 {
3742 	struct smack_known *skp;
3743 	int found = 0;
3744 	int acat;
3745 	int kcat;
3746 
3747 	/*
3748 	 * Netlabel found it in the cache.
3749 	 */
3750 	if ((sap->flags & NETLBL_SECATTR_CACHE) != 0)
3751 		return (struct smack_known *)sap->cache->data;
3752 
3753 	if ((sap->flags & NETLBL_SECATTR_SECID) != 0)
3754 		/*
3755 		 * Looks like a fallback, which gives us a secid.
3756 		 */
3757 		return smack_from_secid(sap->attr.secid);
3758 
3759 	if ((sap->flags & NETLBL_SECATTR_MLS_LVL) != 0) {
3760 		/*
3761 		 * Looks like a CIPSO packet.
3762 		 * If there are flags but no level netlabel isn't
3763 		 * behaving the way we expect it to.
3764 		 *
3765 		 * Look it up in the label table
3766 		 * Without guidance regarding the smack value
3767 		 * for the packet fall back on the network
3768 		 * ambient value.
3769 		 */
3770 		rcu_read_lock();
3771 		list_for_each_entry_rcu(skp, &smack_known_list, list) {
3772 			if (sap->attr.mls.lvl != skp->smk_netlabel.attr.mls.lvl)
3773 				continue;
3774 			/*
3775 			 * Compare the catsets. Use the netlbl APIs.
3776 			 */
3777 			if ((sap->flags & NETLBL_SECATTR_MLS_CAT) == 0) {
3778 				if ((skp->smk_netlabel.flags &
3779 				     NETLBL_SECATTR_MLS_CAT) == 0)
3780 					found = 1;
3781 				break;
3782 			}
3783 			for (acat = -1, kcat = -1; acat == kcat; ) {
3784 				acat = netlbl_catmap_walk(sap->attr.mls.cat,
3785 							  acat + 1);
3786 				kcat = netlbl_catmap_walk(
3787 					skp->smk_netlabel.attr.mls.cat,
3788 					kcat + 1);
3789 				if (acat < 0 || kcat < 0)
3790 					break;
3791 			}
3792 			if (acat == kcat) {
3793 				found = 1;
3794 				break;
3795 			}
3796 		}
3797 		rcu_read_unlock();
3798 
3799 		if (found)
3800 			return skp;
3801 
3802 		if (ssp != NULL && ssp->smk_in == &smack_known_star)
3803 			return &smack_known_web;
3804 		return &smack_known_star;
3805 	}
3806 	/*
3807 	 * Without guidance regarding the smack value
3808 	 * for the packet fall back on the network
3809 	 * ambient value.
3810 	 */
3811 	return smack_net_ambient;
3812 }
3813 
3814 #if IS_ENABLED(CONFIG_IPV6)
smk_skb_to_addr_ipv6(struct sk_buff *skb, struct sockaddr_in6 *sip)3815 static int smk_skb_to_addr_ipv6(struct sk_buff *skb, struct sockaddr_in6 *sip)
3816 {
3817 	u8 nexthdr;
3818 	int offset;
3819 	int proto = -EINVAL;
3820 	struct ipv6hdr _ipv6h;
3821 	struct ipv6hdr *ip6;
3822 	__be16 frag_off;
3823 	struct tcphdr _tcph, *th;
3824 	struct udphdr _udph, *uh;
3825 	struct dccp_hdr _dccph, *dh;
3826 
3827 	sip->sin6_port = 0;
3828 
3829 	offset = skb_network_offset(skb);
3830 	ip6 = skb_header_pointer(skb, offset, sizeof(_ipv6h), &_ipv6h);
3831 	if (ip6 == NULL)
3832 		return -EINVAL;
3833 	sip->sin6_addr = ip6->saddr;
3834 
3835 	nexthdr = ip6->nexthdr;
3836 	offset += sizeof(_ipv6h);
3837 	offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
3838 	if (offset < 0)
3839 		return -EINVAL;
3840 
3841 	proto = nexthdr;
3842 	switch (proto) {
3843 	case IPPROTO_TCP:
3844 		th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
3845 		if (th != NULL)
3846 			sip->sin6_port = th->source;
3847 		break;
3848 	case IPPROTO_UDP:
3849 	case IPPROTO_UDPLITE:
3850 		uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
3851 		if (uh != NULL)
3852 			sip->sin6_port = uh->source;
3853 		break;
3854 	case IPPROTO_DCCP:
3855 		dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
3856 		if (dh != NULL)
3857 			sip->sin6_port = dh->dccph_sport;
3858 		break;
3859 	}
3860 	return proto;
3861 }
3862 #endif /* CONFIG_IPV6 */
3863 
3864 /**
3865  * smack_from_skb - Smack data from the secmark in an skb
3866  * @skb: packet
3867  *
3868  * Returns smack_known of the secmark or NULL if that won't work.
3869  */
3870 #ifdef CONFIG_NETWORK_SECMARK
smack_from_skb(struct sk_buff *skb)3871 static struct smack_known *smack_from_skb(struct sk_buff *skb)
3872 {
3873 	if (skb == NULL || skb->secmark == 0)
3874 		return NULL;
3875 
3876 	return smack_from_secid(skb->secmark);
3877 }
3878 #else
smack_from_skb(struct sk_buff *skb)3879 static inline struct smack_known *smack_from_skb(struct sk_buff *skb)
3880 {
3881 	return NULL;
3882 }
3883 #endif
3884 
3885 /**
3886  * smack_from_netlbl - Smack data from the IP options in an skb
3887  * @sk: socket data came in on
3888  * @family: address family
3889  * @skb: packet
3890  *
3891  * Find the Smack label in the IP options. If it hasn't been
3892  * added to the netlabel cache, add it here.
3893  *
3894  * Returns smack_known of the IP options or NULL if that won't work.
3895  */
smack_from_netlbl(struct sock *sk, u16 family, struct sk_buff *skb)3896 static struct smack_known *smack_from_netlbl(struct sock *sk, u16 family,
3897 					     struct sk_buff *skb)
3898 {
3899 	struct netlbl_lsm_secattr secattr;
3900 	struct socket_smack *ssp = NULL;
3901 	struct smack_known *skp = NULL;
3902 	int rc;
3903 
3904 	netlbl_secattr_init(&secattr);
3905 
3906 	if (sk)
3907 		ssp = sk->sk_security;
3908 
3909 	if (netlbl_skbuff_getattr(skb, family, &secattr) == 0) {
3910 		skp = smack_from_secattr(&secattr, ssp);
3911 		if (secattr.flags & NETLBL_SECATTR_CACHEABLE)
3912 			rc = netlbl_cache_add(skb, family, &skp->smk_netlabel);
3913 	}
3914 
3915 	netlbl_secattr_destroy(&secattr);
3916 
3917 	return skp;
3918 }
3919 
3920 /**
3921  * smack_socket_sock_rcv_skb - Smack packet delivery access check
3922  * @sk: socket
3923  * @skb: packet
3924  *
3925  * Returns 0 if the packet should be delivered, an error code otherwise
3926  */
smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)3927 static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
3928 {
3929 	struct socket_smack *ssp = sk->sk_security;
3930 	struct smack_known *skp = NULL;
3931 	int rc = 0;
3932 	struct smk_audit_info ad;
3933 	u16 family = sk->sk_family;
3934 #ifdef CONFIG_AUDIT
3935 	struct lsm_network_audit net;
3936 #endif
3937 #if IS_ENABLED(CONFIG_IPV6)
3938 	struct sockaddr_in6 sadd;
3939 	int proto;
3940 
3941 	if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP))
3942 		family = PF_INET;
3943 #endif /* CONFIG_IPV6 */
3944 
3945 	switch (family) {
3946 	case PF_INET:
3947 		/*
3948 		 * If there is a secmark use it rather than the CIPSO label.
3949 		 * If there is no secmark fall back to CIPSO.
3950 		 * The secmark is assumed to reflect policy better.
3951 		 */
3952 		skp = smack_from_skb(skb);
3953 		if (skp == NULL) {
3954 			skp = smack_from_netlbl(sk, family, skb);
3955 			if (skp == NULL)
3956 				skp = smack_net_ambient;
3957 		}
3958 
3959 #ifdef CONFIG_AUDIT
3960 		smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
3961 		ad.a.u.net->family = family;
3962 		ad.a.u.net->netif = skb->skb_iif;
3963 		ipv4_skb_to_auditdata(skb, &ad.a, NULL);
3964 #endif
3965 		/*
3966 		 * Receiving a packet requires that the other end
3967 		 * be able to write here. Read access is not required.
3968 		 * This is the simplist possible security model
3969 		 * for networking.
3970 		 */
3971 		rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
3972 		rc = smk_bu_note("IPv4 delivery", skp, ssp->smk_in,
3973 					MAY_WRITE, rc);
3974 		if (rc != 0)
3975 			netlbl_skbuff_err(skb, family, rc, 0);
3976 		break;
3977 #if IS_ENABLED(CONFIG_IPV6)
3978 	case PF_INET6:
3979 		proto = smk_skb_to_addr_ipv6(skb, &sadd);
3980 		if (proto != IPPROTO_UDP && proto != IPPROTO_UDPLITE &&
3981 		    proto != IPPROTO_TCP && proto != IPPROTO_DCCP)
3982 			break;
3983 #ifdef SMACK_IPV6_SECMARK_LABELING
3984 		skp = smack_from_skb(skb);
3985 		if (skp == NULL) {
3986 			if (smk_ipv6_localhost(&sadd))
3987 				break;
3988 			skp = smack_ipv6host_label(&sadd);
3989 			if (skp == NULL)
3990 				skp = smack_net_ambient;
3991 		}
3992 #ifdef CONFIG_AUDIT
3993 		smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
3994 		ad.a.u.net->family = family;
3995 		ad.a.u.net->netif = skb->skb_iif;
3996 		ipv6_skb_to_auditdata(skb, &ad.a, NULL);
3997 #endif /* CONFIG_AUDIT */
3998 		rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
3999 		rc = smk_bu_note("IPv6 delivery", skp, ssp->smk_in,
4000 					MAY_WRITE, rc);
4001 #endif /* SMACK_IPV6_SECMARK_LABELING */
4002 #ifdef SMACK_IPV6_PORT_LABELING
4003 		rc = smk_ipv6_port_check(sk, &sadd, SMK_RECEIVING);
4004 #endif /* SMACK_IPV6_PORT_LABELING */
4005 		if (rc != 0)
4006 			icmpv6_send(skb, ICMPV6_DEST_UNREACH,
4007 					ICMPV6_ADM_PROHIBITED, 0);
4008 		break;
4009 #endif /* CONFIG_IPV6 */
4010 	}
4011 
4012 	return rc;
4013 }
4014 
4015 /**
4016  * smack_socket_getpeersec_stream - pull in packet label
4017  * @sock: the socket
4018  * @optval: user's destination
4019  * @optlen: size thereof
4020  * @len: max thereof
4021  *
4022  * returns zero on success, an error code otherwise
4023  */
smack_socket_getpeersec_stream(struct socket *sock, char __user *optval, int __user *optlen, unsigned len)4024 static int smack_socket_getpeersec_stream(struct socket *sock,
4025 					  char __user *optval,
4026 					  int __user *optlen, unsigned len)
4027 {
4028 	struct socket_smack *ssp;
4029 	char *rcp = "";
4030 	int slen = 1;
4031 	int rc = 0;
4032 
4033 	ssp = sock->sk->sk_security;
4034 	if (ssp->smk_packet != NULL) {
4035 		rcp = ssp->smk_packet->smk_known;
4036 		slen = strlen(rcp) + 1;
4037 	}
4038 
4039 	if (slen > len)
4040 		rc = -ERANGE;
4041 	else if (copy_to_user(optval, rcp, slen) != 0)
4042 		rc = -EFAULT;
4043 
4044 	if (put_user(slen, optlen) != 0)
4045 		rc = -EFAULT;
4046 
4047 	return rc;
4048 }
4049 
4050 
4051 /**
4052  * smack_socket_getpeersec_dgram - pull in packet label
4053  * @sock: the peer socket
4054  * @skb: packet data
4055  * @secid: pointer to where to put the secid of the packet
4056  *
4057  * Sets the netlabel socket state on sk from parent
4058  */
smack_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid)4059 static int smack_socket_getpeersec_dgram(struct socket *sock,
4060 					 struct sk_buff *skb, u32 *secid)
4061 
4062 {
4063 	struct socket_smack *ssp = NULL;
4064 	struct smack_known *skp;
4065 	struct sock *sk = NULL;
4066 	int family = PF_UNSPEC;
4067 	u32 s = 0;	/* 0 is the invalid secid */
4068 
4069 	if (skb != NULL) {
4070 		if (skb->protocol == htons(ETH_P_IP))
4071 			family = PF_INET;
4072 #if IS_ENABLED(CONFIG_IPV6)
4073 		else if (skb->protocol == htons(ETH_P_IPV6))
4074 			family = PF_INET6;
4075 #endif /* CONFIG_IPV6 */
4076 	}
4077 	if (family == PF_UNSPEC && sock != NULL)
4078 		family = sock->sk->sk_family;
4079 
4080 	switch (family) {
4081 	case PF_UNIX:
4082 		ssp = sock->sk->sk_security;
4083 		s = ssp->smk_out->smk_secid;
4084 		break;
4085 	case PF_INET:
4086 		skp = smack_from_skb(skb);
4087 		if (skp) {
4088 			s = skp->smk_secid;
4089 			break;
4090 		}
4091 		/*
4092 		 * Translate what netlabel gave us.
4093 		 */
4094 		if (sock != NULL)
4095 			sk = sock->sk;
4096 		skp = smack_from_netlbl(sk, family, skb);
4097 		if (skp != NULL)
4098 			s = skp->smk_secid;
4099 		break;
4100 	case PF_INET6:
4101 #ifdef SMACK_IPV6_SECMARK_LABELING
4102 		skp = smack_from_skb(skb);
4103 		if (skp)
4104 			s = skp->smk_secid;
4105 #endif
4106 		break;
4107 	}
4108 	*secid = s;
4109 	if (s == 0)
4110 		return -EINVAL;
4111 	return 0;
4112 }
4113 
4114 /**
4115  * smack_sock_graft - Initialize a newly created socket with an existing sock
4116  * @sk: child sock
4117  * @parent: parent socket
4118  *
4119  * Set the smk_{in,out} state of an existing sock based on the process that
4120  * is creating the new socket.
4121  */
smack_sock_graft(struct sock *sk, struct socket *parent)4122 static void smack_sock_graft(struct sock *sk, struct socket *parent)
4123 {
4124 	struct socket_smack *ssp;
4125 	struct smack_known *skp = smk_of_current();
4126 
4127 	if (sk == NULL ||
4128 	    (sk->sk_family != PF_INET && sk->sk_family != PF_INET6))
4129 		return;
4130 
4131 	ssp = sk->sk_security;
4132 	ssp->smk_in = skp;
4133 	ssp->smk_out = skp;
4134 	/* cssp->smk_packet is already set in smack_inet_csk_clone() */
4135 }
4136 
4137 /**
4138  * smack_inet_conn_request - Smack access check on connect
4139  * @sk: socket involved
4140  * @skb: packet
4141  * @req: unused
4142  *
4143  * Returns 0 if a task with the packet label could write to
4144  * the socket, otherwise an error code
4145  */
smack_inet_conn_request(struct sock *sk, struct sk_buff *skb, struct request_sock *req)4146 static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
4147 				   struct request_sock *req)
4148 {
4149 	u16 family = sk->sk_family;
4150 	struct smack_known *skp;
4151 	struct socket_smack *ssp = sk->sk_security;
4152 	struct sockaddr_in addr;
4153 	struct iphdr *hdr;
4154 	struct smack_known *hskp;
4155 	int rc;
4156 	struct smk_audit_info ad;
4157 #ifdef CONFIG_AUDIT
4158 	struct lsm_network_audit net;
4159 #endif
4160 
4161 #if IS_ENABLED(CONFIG_IPV6)
4162 	if (family == PF_INET6) {
4163 		/*
4164 		 * Handle mapped IPv4 packets arriving
4165 		 * via IPv6 sockets. Don't set up netlabel
4166 		 * processing on IPv6.
4167 		 */
4168 		if (skb->protocol == htons(ETH_P_IP))
4169 			family = PF_INET;
4170 		else
4171 			return 0;
4172 	}
4173 #endif /* CONFIG_IPV6 */
4174 
4175 	/*
4176 	 * If there is a secmark use it rather than the CIPSO label.
4177 	 * If there is no secmark fall back to CIPSO.
4178 	 * The secmark is assumed to reflect policy better.
4179 	 */
4180 	skp = smack_from_skb(skb);
4181 	if (skp == NULL) {
4182 		skp = smack_from_netlbl(sk, family, skb);
4183 		if (skp == NULL)
4184 			skp = &smack_known_huh;
4185 	}
4186 
4187 #ifdef CONFIG_AUDIT
4188 	smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
4189 	ad.a.u.net->family = family;
4190 	ad.a.u.net->netif = skb->skb_iif;
4191 	ipv4_skb_to_auditdata(skb, &ad.a, NULL);
4192 #endif
4193 	/*
4194 	 * Receiving a packet requires that the other end be able to write
4195 	 * here. Read access is not required.
4196 	 */
4197 	rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
4198 	rc = smk_bu_note("IPv4 connect", skp, ssp->smk_in, MAY_WRITE, rc);
4199 	if (rc != 0)
4200 		return rc;
4201 
4202 	/*
4203 	 * Save the peer's label in the request_sock so we can later setup
4204 	 * smk_packet in the child socket so that SO_PEERCRED can report it.
4205 	 */
4206 	req->peer_secid = skp->smk_secid;
4207 
4208 	/*
4209 	 * We need to decide if we want to label the incoming connection here
4210 	 * if we do we only need to label the request_sock and the stack will
4211 	 * propagate the wire-label to the sock when it is created.
4212 	 */
4213 	hdr = ip_hdr(skb);
4214 	addr.sin_addr.s_addr = hdr->saddr;
4215 	rcu_read_lock();
4216 	hskp = smack_ipv4host_label(&addr);
4217 	rcu_read_unlock();
4218 
4219 	if (hskp == NULL)
4220 		rc = netlbl_req_setattr(req, &skp->smk_netlabel);
4221 	else
4222 		netlbl_req_delattr(req);
4223 
4224 	return rc;
4225 }
4226 
4227 /**
4228  * smack_inet_csk_clone - Copy the connection information to the new socket
4229  * @sk: the new socket
4230  * @req: the connection's request_sock
4231  *
4232  * Transfer the connection's peer label to the newly created socket.
4233  */
smack_inet_csk_clone(struct sock *sk, const struct request_sock *req)4234 static void smack_inet_csk_clone(struct sock *sk,
4235 				 const struct request_sock *req)
4236 {
4237 	struct socket_smack *ssp = sk->sk_security;
4238 	struct smack_known *skp;
4239 
4240 	if (req->peer_secid != 0) {
4241 		skp = smack_from_secid(req->peer_secid);
4242 		ssp->smk_packet = skp;
4243 	} else
4244 		ssp->smk_packet = NULL;
4245 }
4246 
4247 /*
4248  * Key management security hooks
4249  *
4250  * Casey has not tested key support very heavily.
4251  * The permission check is most likely too restrictive.
4252  * If you care about keys please have a look.
4253  */
4254 #ifdef CONFIG_KEYS
4255 
4256 /**
4257  * smack_key_alloc - Set the key security blob
4258  * @key: object
4259  * @cred: the credentials to use
4260  * @flags: unused
4261  *
4262  * No allocation required
4263  *
4264  * Returns 0
4265  */
smack_key_alloc(struct key *key, const struct cred *cred, unsigned long flags)4266 static int smack_key_alloc(struct key *key, const struct cred *cred,
4267 			   unsigned long flags)
4268 {
4269 	struct smack_known *skp = smk_of_task(smack_cred(cred));
4270 
4271 	key->security = skp;
4272 	return 0;
4273 }
4274 
4275 /**
4276  * smack_key_free - Clear the key security blob
4277  * @key: the object
4278  *
4279  * Clear the blob pointer
4280  */
smack_key_free(struct key *key)4281 static void smack_key_free(struct key *key)
4282 {
4283 	key->security = NULL;
4284 }
4285 
4286 /**
4287  * smack_key_permission - Smack access on a key
4288  * @key_ref: gets to the object
4289  * @cred: the credentials to use
4290  * @need_perm: requested key permission
4291  *
4292  * Return 0 if the task has read and write to the object,
4293  * an error code otherwise
4294  */
smack_key_permission(key_ref_t key_ref, const struct cred *cred, enum key_need_perm need_perm)4295 static int smack_key_permission(key_ref_t key_ref,
4296 				const struct cred *cred,
4297 				enum key_need_perm need_perm)
4298 {
4299 	struct key *keyp;
4300 	struct smk_audit_info ad;
4301 	struct smack_known *tkp = smk_of_task(smack_cred(cred));
4302 	int request = 0;
4303 	int rc;
4304 
4305 	/*
4306 	 * Validate requested permissions
4307 	 */
4308 	switch (need_perm) {
4309 	case KEY_NEED_READ:
4310 	case KEY_NEED_SEARCH:
4311 	case KEY_NEED_VIEW:
4312 		request |= MAY_READ;
4313 		break;
4314 	case KEY_NEED_WRITE:
4315 	case KEY_NEED_LINK:
4316 	case KEY_NEED_SETATTR:
4317 		request |= MAY_WRITE;
4318 		break;
4319 	case KEY_NEED_UNSPECIFIED:
4320 	case KEY_NEED_UNLINK:
4321 	case KEY_SYSADMIN_OVERRIDE:
4322 	case KEY_AUTHTOKEN_OVERRIDE:
4323 	case KEY_DEFER_PERM_CHECK:
4324 		return 0;
4325 	default:
4326 		return -EINVAL;
4327 	}
4328 
4329 	keyp = key_ref_to_ptr(key_ref);
4330 	if (keyp == NULL)
4331 		return -EINVAL;
4332 	/*
4333 	 * If the key hasn't been initialized give it access so that
4334 	 * it may do so.
4335 	 */
4336 	if (keyp->security == NULL)
4337 		return 0;
4338 	/*
4339 	 * This should not occur
4340 	 */
4341 	if (tkp == NULL)
4342 		return -EACCES;
4343 
4344 	if (smack_privileged(CAP_MAC_OVERRIDE))
4345 		return 0;
4346 
4347 #ifdef CONFIG_AUDIT
4348 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_KEY);
4349 	ad.a.u.key_struct.key = keyp->serial;
4350 	ad.a.u.key_struct.key_desc = keyp->description;
4351 #endif
4352 	rc = smk_access(tkp, keyp->security, request, &ad);
4353 	rc = smk_bu_note("key access", tkp, keyp->security, request, rc);
4354 	return rc;
4355 }
4356 
4357 /*
4358  * smack_key_getsecurity - Smack label tagging the key
4359  * @key points to the key to be queried
4360  * @_buffer points to a pointer that should be set to point to the
4361  * resulting string (if no label or an error occurs).
4362  * Return the length of the string (including terminating NUL) or -ve if
4363  * an error.
4364  * May also return 0 (and a NULL buffer pointer) if there is no label.
4365  */
smack_key_getsecurity(struct key *key, char **_buffer)4366 static int smack_key_getsecurity(struct key *key, char **_buffer)
4367 {
4368 	struct smack_known *skp = key->security;
4369 	size_t length;
4370 	char *copy;
4371 
4372 	if (key->security == NULL) {
4373 		*_buffer = NULL;
4374 		return 0;
4375 	}
4376 
4377 	copy = kstrdup(skp->smk_known, GFP_KERNEL);
4378 	if (copy == NULL)
4379 		return -ENOMEM;
4380 	length = strlen(copy) + 1;
4381 
4382 	*_buffer = copy;
4383 	return length;
4384 }
4385 
4386 
4387 #ifdef CONFIG_KEY_NOTIFICATIONS
4388 /**
4389  * smack_watch_key - Smack access to watch a key for notifications.
4390  * @key: The key to be watched
4391  *
4392  * Return 0 if the @watch->cred has permission to read from the key object and
4393  * an error otherwise.
4394  */
smack_watch_key(struct key *key)4395 static int smack_watch_key(struct key *key)
4396 {
4397 	struct smk_audit_info ad;
4398 	struct smack_known *tkp = smk_of_current();
4399 	int rc;
4400 
4401 	if (key == NULL)
4402 		return -EINVAL;
4403 	/*
4404 	 * If the key hasn't been initialized give it access so that
4405 	 * it may do so.
4406 	 */
4407 	if (key->security == NULL)
4408 		return 0;
4409 	/*
4410 	 * This should not occur
4411 	 */
4412 	if (tkp == NULL)
4413 		return -EACCES;
4414 
4415 	if (smack_privileged_cred(CAP_MAC_OVERRIDE, current_cred()))
4416 		return 0;
4417 
4418 #ifdef CONFIG_AUDIT
4419 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_KEY);
4420 	ad.a.u.key_struct.key = key->serial;
4421 	ad.a.u.key_struct.key_desc = key->description;
4422 #endif
4423 	rc = smk_access(tkp, key->security, MAY_READ, &ad);
4424 	rc = smk_bu_note("key watch", tkp, key->security, MAY_READ, rc);
4425 	return rc;
4426 }
4427 #endif /* CONFIG_KEY_NOTIFICATIONS */
4428 #endif /* CONFIG_KEYS */
4429 
4430 #ifdef CONFIG_WATCH_QUEUE
4431 /**
4432  * smack_post_notification - Smack access to post a notification to a queue
4433  * @w_cred: The credentials of the watcher.
4434  * @cred: The credentials of the event source (may be NULL).
4435  * @n: The notification message to be posted.
4436  */
smack_post_notification(const struct cred *w_cred, const struct cred *cred, struct watch_notification *n)4437 static int smack_post_notification(const struct cred *w_cred,
4438 				   const struct cred *cred,
4439 				   struct watch_notification *n)
4440 {
4441 	struct smk_audit_info ad;
4442 	struct smack_known *subj, *obj;
4443 	int rc;
4444 
4445 	/* Always let maintenance notifications through. */
4446 	if (n->type == WATCH_TYPE_META)
4447 		return 0;
4448 
4449 	if (!cred)
4450 		return 0;
4451 	subj = smk_of_task(smack_cred(cred));
4452 	obj = smk_of_task(smack_cred(w_cred));
4453 
4454 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_NOTIFICATION);
4455 	rc = smk_access(subj, obj, MAY_WRITE, &ad);
4456 	rc = smk_bu_note("notification", subj, obj, MAY_WRITE, rc);
4457 	return rc;
4458 }
4459 #endif /* CONFIG_WATCH_QUEUE */
4460 
4461 /*
4462  * Smack Audit hooks
4463  *
4464  * Audit requires a unique representation of each Smack specific
4465  * rule. This unique representation is used to distinguish the
4466  * object to be audited from remaining kernel objects and also
4467  * works as a glue between the audit hooks.
4468  *
4469  * Since repository entries are added but never deleted, we'll use
4470  * the smack_known label address related to the given audit rule as
4471  * the needed unique representation. This also better fits the smack
4472  * model where nearly everything is a label.
4473  */
4474 #ifdef CONFIG_AUDIT
4475 
4476 /**
4477  * smack_audit_rule_init - Initialize a smack audit rule
4478  * @field: audit rule fields given from user-space (audit.h)
4479  * @op: required testing operator (=, !=, >, <, ...)
4480  * @rulestr: smack label to be audited
4481  * @vrule: pointer to save our own audit rule representation
4482  *
4483  * Prepare to audit cases where (@field @op @rulestr) is true.
4484  * The label to be audited is created if necessay.
4485  */
smack_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)4486 static int smack_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
4487 {
4488 	struct smack_known *skp;
4489 	char **rule = (char **)vrule;
4490 	*rule = NULL;
4491 
4492 	if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
4493 		return -EINVAL;
4494 
4495 	if (op != Audit_equal && op != Audit_not_equal)
4496 		return -EINVAL;
4497 
4498 	skp = smk_import_entry(rulestr, 0);
4499 	if (IS_ERR(skp))
4500 		return PTR_ERR(skp);
4501 
4502 	*rule = skp->smk_known;
4503 
4504 	return 0;
4505 }
4506 
4507 /**
4508  * smack_audit_rule_known - Distinguish Smack audit rules
4509  * @krule: rule of interest, in Audit kernel representation format
4510  *
4511  * This is used to filter Smack rules from remaining Audit ones.
4512  * If it's proved that this rule belongs to us, the
4513  * audit_rule_match hook will be called to do the final judgement.
4514  */
smack_audit_rule_known(struct audit_krule *krule)4515 static int smack_audit_rule_known(struct audit_krule *krule)
4516 {
4517 	struct audit_field *f;
4518 	int i;
4519 
4520 	for (i = 0; i < krule->field_count; i++) {
4521 		f = &krule->fields[i];
4522 
4523 		if (f->type == AUDIT_SUBJ_USER || f->type == AUDIT_OBJ_USER)
4524 			return 1;
4525 	}
4526 
4527 	return 0;
4528 }
4529 
4530 /**
4531  * smack_audit_rule_match - Audit given object ?
4532  * @secid: security id for identifying the object to test
4533  * @field: audit rule flags given from user-space
4534  * @op: required testing operator
4535  * @vrule: smack internal rule presentation
4536  *
4537  * The core Audit hook. It's used to take the decision of
4538  * whether to audit or not to audit a given object.
4539  */
smack_audit_rule_match(u32 secid, u32 field, u32 op, void *vrule)4540 static int smack_audit_rule_match(u32 secid, u32 field, u32 op, void *vrule)
4541 {
4542 	struct smack_known *skp;
4543 	char *rule = vrule;
4544 
4545 	if (unlikely(!rule)) {
4546 		WARN_ONCE(1, "Smack: missing rule\n");
4547 		return -ENOENT;
4548 	}
4549 
4550 	if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
4551 		return 0;
4552 
4553 	skp = smack_from_secid(secid);
4554 
4555 	/*
4556 	 * No need to do string comparisons. If a match occurs,
4557 	 * both pointers will point to the same smack_known
4558 	 * label.
4559 	 */
4560 	if (op == Audit_equal)
4561 		return (rule == skp->smk_known);
4562 	if (op == Audit_not_equal)
4563 		return (rule != skp->smk_known);
4564 
4565 	return 0;
4566 }
4567 
4568 /*
4569  * There is no need for a smack_audit_rule_free hook.
4570  * No memory was allocated.
4571  */
4572 
4573 #endif /* CONFIG_AUDIT */
4574 
4575 /**
4576  * smack_ismaclabel - check if xattr @name references a smack MAC label
4577  * @name: Full xattr name to check.
4578  */
smack_ismaclabel(const char *name)4579 static int smack_ismaclabel(const char *name)
4580 {
4581 	return (strcmp(name, XATTR_SMACK_SUFFIX) == 0);
4582 }
4583 
4584 
4585 /**
4586  * smack_secid_to_secctx - return the smack label for a secid
4587  * @secid: incoming integer
4588  * @secdata: destination
4589  * @seclen: how long it is
4590  *
4591  * Exists for networking code.
4592  */
smack_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)4593 static int smack_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
4594 {
4595 	struct smack_known *skp = smack_from_secid(secid);
4596 
4597 	if (secdata)
4598 		*secdata = skp->smk_known;
4599 	*seclen = strlen(skp->smk_known);
4600 	return 0;
4601 }
4602 
4603 /**
4604  * smack_secctx_to_secid - return the secid for a smack label
4605  * @secdata: smack label
4606  * @seclen: how long result is
4607  * @secid: outgoing integer
4608  *
4609  * Exists for audit and networking code.
4610  */
smack_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)4611 static int smack_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
4612 {
4613 	struct smack_known *skp = smk_find_entry(secdata);
4614 
4615 	if (skp)
4616 		*secid = skp->smk_secid;
4617 	else
4618 		*secid = 0;
4619 	return 0;
4620 }
4621 
4622 /*
4623  * There used to be a smack_release_secctx hook
4624  * that did nothing back when hooks were in a vector.
4625  * Now that there's a list such a hook adds cost.
4626  */
4627 
smack_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen)4628 static int smack_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen)
4629 {
4630 	return smack_inode_setsecurity(inode, XATTR_SMACK_SUFFIX, ctx, ctxlen, 0);
4631 }
4632 
smack_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)4633 static int smack_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
4634 {
4635 	return __vfs_setxattr_noperm(dentry, XATTR_NAME_SMACK, ctx, ctxlen, 0);
4636 }
4637 
smack_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)4638 static int smack_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
4639 {
4640 	struct smack_known *skp = smk_of_inode(inode);
4641 
4642 	*ctx = skp->smk_known;
4643 	*ctxlen = strlen(skp->smk_known);
4644 	return 0;
4645 }
4646 
smack_inode_copy_up(struct dentry *dentry, struct cred **new)4647 static int smack_inode_copy_up(struct dentry *dentry, struct cred **new)
4648 {
4649 
4650 	struct task_smack *tsp;
4651 	struct smack_known *skp;
4652 	struct inode_smack *isp;
4653 	struct cred *new_creds = *new;
4654 
4655 	if (new_creds == NULL) {
4656 		new_creds = prepare_creds();
4657 		if (new_creds == NULL)
4658 			return -ENOMEM;
4659 	}
4660 
4661 	tsp = smack_cred(new_creds);
4662 
4663 	/*
4664 	 * Get label from overlay inode and set it in create_sid
4665 	 */
4666 	isp = smack_inode(d_inode(dentry));
4667 	skp = isp->smk_inode;
4668 	tsp->smk_task = skp;
4669 	*new = new_creds;
4670 	return 0;
4671 }
4672 
smack_inode_copy_up_xattr(const char *name)4673 static int smack_inode_copy_up_xattr(const char *name)
4674 {
4675 	/*
4676 	 * Return 1 if this is the smack access Smack attribute.
4677 	 */
4678 	if (strcmp(name, XATTR_NAME_SMACK) == 0)
4679 		return 1;
4680 
4681 	return -EOPNOTSUPP;
4682 }
4683 
smack_dentry_create_files_as(struct dentry *dentry, int mode, struct qstr *name, const struct cred *old, struct cred *new)4684 static int smack_dentry_create_files_as(struct dentry *dentry, int mode,
4685 					struct qstr *name,
4686 					const struct cred *old,
4687 					struct cred *new)
4688 {
4689 	struct task_smack *otsp = smack_cred(old);
4690 	struct task_smack *ntsp = smack_cred(new);
4691 	struct inode_smack *isp;
4692 	int may;
4693 
4694 	/*
4695 	 * Use the process credential unless all of
4696 	 * the transmuting criteria are met
4697 	 */
4698 	ntsp->smk_task = otsp->smk_task;
4699 
4700 	/*
4701 	 * the attribute of the containing directory
4702 	 */
4703 	isp = smack_inode(d_inode(dentry->d_parent));
4704 
4705 	if (isp->smk_flags & SMK_INODE_TRANSMUTE) {
4706 		rcu_read_lock();
4707 		may = smk_access_entry(otsp->smk_task->smk_known,
4708 				       isp->smk_inode->smk_known,
4709 				       &otsp->smk_task->smk_rules);
4710 		rcu_read_unlock();
4711 
4712 		/*
4713 		 * If the directory is transmuting and the rule
4714 		 * providing access is transmuting use the containing
4715 		 * directory label instead of the process label.
4716 		 */
4717 		if (may > 0 && (may & MAY_TRANSMUTE)) {
4718 			ntsp->smk_task = isp->smk_inode;
4719 			ntsp->smk_transmuted = ntsp->smk_task;
4720 		}
4721 	}
4722 	return 0;
4723 }
4724 
4725 struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
4726 	.lbs_cred = sizeof(struct task_smack),
4727 	.lbs_file = sizeof(struct smack_known *),
4728 	.lbs_inode = sizeof(struct inode_smack),
4729 	.lbs_ipc = sizeof(struct smack_known *),
4730 	.lbs_msg_msg = sizeof(struct smack_known *),
4731 };
4732 
4733 static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
4734 	LSM_HOOK_INIT(ptrace_access_check, smack_ptrace_access_check),
4735 	LSM_HOOK_INIT(ptrace_traceme, smack_ptrace_traceme),
4736 	LSM_HOOK_INIT(syslog, smack_syslog),
4737 
4738 	LSM_HOOK_INIT(fs_context_dup, smack_fs_context_dup),
4739 	LSM_HOOK_INIT(fs_context_parse_param, smack_fs_context_parse_param),
4740 
4741 	LSM_HOOK_INIT(sb_alloc_security, smack_sb_alloc_security),
4742 	LSM_HOOK_INIT(sb_free_security, smack_sb_free_security),
4743 	LSM_HOOK_INIT(sb_free_mnt_opts, smack_free_mnt_opts),
4744 	LSM_HOOK_INIT(sb_eat_lsm_opts, smack_sb_eat_lsm_opts),
4745 	LSM_HOOK_INIT(sb_statfs, smack_sb_statfs),
4746 	LSM_HOOK_INIT(sb_set_mnt_opts, smack_set_mnt_opts),
4747 
4748 	LSM_HOOK_INIT(bprm_creds_for_exec, smack_bprm_creds_for_exec),
4749 
4750 	LSM_HOOK_INIT(inode_alloc_security, smack_inode_alloc_security),
4751 	LSM_HOOK_INIT(inode_init_security, smack_inode_init_security),
4752 	LSM_HOOK_INIT(inode_link, smack_inode_link),
4753 	LSM_HOOK_INIT(inode_unlink, smack_inode_unlink),
4754 	LSM_HOOK_INIT(inode_rmdir, smack_inode_rmdir),
4755 	LSM_HOOK_INIT(inode_rename, smack_inode_rename),
4756 	LSM_HOOK_INIT(inode_permission, smack_inode_permission),
4757 	LSM_HOOK_INIT(inode_setattr, smack_inode_setattr),
4758 	LSM_HOOK_INIT(inode_getattr, smack_inode_getattr),
4759 	LSM_HOOK_INIT(inode_setxattr, smack_inode_setxattr),
4760 	LSM_HOOK_INIT(inode_post_setxattr, smack_inode_post_setxattr),
4761 	LSM_HOOK_INIT(inode_getxattr, smack_inode_getxattr),
4762 	LSM_HOOK_INIT(inode_removexattr, smack_inode_removexattr),
4763 	LSM_HOOK_INIT(inode_getsecurity, smack_inode_getsecurity),
4764 	LSM_HOOK_INIT(inode_setsecurity, smack_inode_setsecurity),
4765 	LSM_HOOK_INIT(inode_listsecurity, smack_inode_listsecurity),
4766 	LSM_HOOK_INIT(inode_getsecid, smack_inode_getsecid),
4767 
4768 	LSM_HOOK_INIT(file_alloc_security, smack_file_alloc_security),
4769 	LSM_HOOK_INIT(file_ioctl, smack_file_ioctl),
4770 	LSM_HOOK_INIT(file_ioctl_compat, smack_file_ioctl),
4771 	LSM_HOOK_INIT(file_lock, smack_file_lock),
4772 	LSM_HOOK_INIT(file_fcntl, smack_file_fcntl),
4773 	LSM_HOOK_INIT(mmap_file, smack_mmap_file),
4774 	LSM_HOOK_INIT(mmap_addr, cap_mmap_addr),
4775 	LSM_HOOK_INIT(file_set_fowner, smack_file_set_fowner),
4776 	LSM_HOOK_INIT(file_send_sigiotask, smack_file_send_sigiotask),
4777 	LSM_HOOK_INIT(file_receive, smack_file_receive),
4778 
4779 	LSM_HOOK_INIT(file_open, smack_file_open),
4780 
4781 	LSM_HOOK_INIT(cred_alloc_blank, smack_cred_alloc_blank),
4782 	LSM_HOOK_INIT(cred_free, smack_cred_free),
4783 	LSM_HOOK_INIT(cred_prepare, smack_cred_prepare),
4784 	LSM_HOOK_INIT(cred_transfer, smack_cred_transfer),
4785 	LSM_HOOK_INIT(cred_getsecid, smack_cred_getsecid),
4786 	LSM_HOOK_INIT(kernel_act_as, smack_kernel_act_as),
4787 	LSM_HOOK_INIT(kernel_create_files_as, smack_kernel_create_files_as),
4788 	LSM_HOOK_INIT(task_setpgid, smack_task_setpgid),
4789 	LSM_HOOK_INIT(task_getpgid, smack_task_getpgid),
4790 	LSM_HOOK_INIT(task_getsid, smack_task_getsid),
4791 	LSM_HOOK_INIT(task_getsecid, smack_task_getsecid),
4792 	LSM_HOOK_INIT(task_setnice, smack_task_setnice),
4793 	LSM_HOOK_INIT(task_setioprio, smack_task_setioprio),
4794 	LSM_HOOK_INIT(task_getioprio, smack_task_getioprio),
4795 	LSM_HOOK_INIT(task_setscheduler, smack_task_setscheduler),
4796 	LSM_HOOK_INIT(task_getscheduler, smack_task_getscheduler),
4797 	LSM_HOOK_INIT(task_movememory, smack_task_movememory),
4798 	LSM_HOOK_INIT(task_kill, smack_task_kill),
4799 	LSM_HOOK_INIT(task_to_inode, smack_task_to_inode),
4800 
4801 	LSM_HOOK_INIT(ipc_permission, smack_ipc_permission),
4802 	LSM_HOOK_INIT(ipc_getsecid, smack_ipc_getsecid),
4803 
4804 	LSM_HOOK_INIT(msg_msg_alloc_security, smack_msg_msg_alloc_security),
4805 
4806 	LSM_HOOK_INIT(msg_queue_alloc_security, smack_ipc_alloc_security),
4807 	LSM_HOOK_INIT(msg_queue_associate, smack_msg_queue_associate),
4808 	LSM_HOOK_INIT(msg_queue_msgctl, smack_msg_queue_msgctl),
4809 	LSM_HOOK_INIT(msg_queue_msgsnd, smack_msg_queue_msgsnd),
4810 	LSM_HOOK_INIT(msg_queue_msgrcv, smack_msg_queue_msgrcv),
4811 
4812 	LSM_HOOK_INIT(shm_alloc_security, smack_ipc_alloc_security),
4813 	LSM_HOOK_INIT(shm_associate, smack_shm_associate),
4814 	LSM_HOOK_INIT(shm_shmctl, smack_shm_shmctl),
4815 	LSM_HOOK_INIT(shm_shmat, smack_shm_shmat),
4816 
4817 	LSM_HOOK_INIT(sem_alloc_security, smack_ipc_alloc_security),
4818 	LSM_HOOK_INIT(sem_associate, smack_sem_associate),
4819 	LSM_HOOK_INIT(sem_semctl, smack_sem_semctl),
4820 	LSM_HOOK_INIT(sem_semop, smack_sem_semop),
4821 
4822 	LSM_HOOK_INIT(d_instantiate, smack_d_instantiate),
4823 
4824 	LSM_HOOK_INIT(getprocattr, smack_getprocattr),
4825 	LSM_HOOK_INIT(setprocattr, smack_setprocattr),
4826 
4827 	LSM_HOOK_INIT(unix_stream_connect, smack_unix_stream_connect),
4828 	LSM_HOOK_INIT(unix_may_send, smack_unix_may_send),
4829 
4830 	LSM_HOOK_INIT(socket_post_create, smack_socket_post_create),
4831 	LSM_HOOK_INIT(socket_socketpair, smack_socket_socketpair),
4832 #ifdef SMACK_IPV6_PORT_LABELING
4833 	LSM_HOOK_INIT(socket_bind, smack_socket_bind),
4834 #endif
4835 	LSM_HOOK_INIT(socket_connect, smack_socket_connect),
4836 	LSM_HOOK_INIT(socket_sendmsg, smack_socket_sendmsg),
4837 	LSM_HOOK_INIT(socket_sock_rcv_skb, smack_socket_sock_rcv_skb),
4838 	LSM_HOOK_INIT(socket_getpeersec_stream, smack_socket_getpeersec_stream),
4839 	LSM_HOOK_INIT(socket_getpeersec_dgram, smack_socket_getpeersec_dgram),
4840 	LSM_HOOK_INIT(sk_alloc_security, smack_sk_alloc_security),
4841 	LSM_HOOK_INIT(sk_free_security, smack_sk_free_security),
4842 	LSM_HOOK_INIT(sock_graft, smack_sock_graft),
4843 	LSM_HOOK_INIT(inet_conn_request, smack_inet_conn_request),
4844 	LSM_HOOK_INIT(inet_csk_clone, smack_inet_csk_clone),
4845 
4846  /* key management security hooks */
4847 #ifdef CONFIG_KEYS
4848 	LSM_HOOK_INIT(key_alloc, smack_key_alloc),
4849 	LSM_HOOK_INIT(key_free, smack_key_free),
4850 	LSM_HOOK_INIT(key_permission, smack_key_permission),
4851 	LSM_HOOK_INIT(key_getsecurity, smack_key_getsecurity),
4852 #ifdef CONFIG_KEY_NOTIFICATIONS
4853 	LSM_HOOK_INIT(watch_key, smack_watch_key),
4854 #endif
4855 #endif /* CONFIG_KEYS */
4856 
4857 #ifdef CONFIG_WATCH_QUEUE
4858 	LSM_HOOK_INIT(post_notification, smack_post_notification),
4859 #endif
4860 
4861  /* Audit hooks */
4862 #ifdef CONFIG_AUDIT
4863 	LSM_HOOK_INIT(audit_rule_init, smack_audit_rule_init),
4864 	LSM_HOOK_INIT(audit_rule_known, smack_audit_rule_known),
4865 	LSM_HOOK_INIT(audit_rule_match, smack_audit_rule_match),
4866 #endif /* CONFIG_AUDIT */
4867 
4868 	LSM_HOOK_INIT(ismaclabel, smack_ismaclabel),
4869 	LSM_HOOK_INIT(secid_to_secctx, smack_secid_to_secctx),
4870 	LSM_HOOK_INIT(secctx_to_secid, smack_secctx_to_secid),
4871 	LSM_HOOK_INIT(inode_notifysecctx, smack_inode_notifysecctx),
4872 	LSM_HOOK_INIT(inode_setsecctx, smack_inode_setsecctx),
4873 	LSM_HOOK_INIT(inode_getsecctx, smack_inode_getsecctx),
4874 	LSM_HOOK_INIT(inode_copy_up, smack_inode_copy_up),
4875 	LSM_HOOK_INIT(inode_copy_up_xattr, smack_inode_copy_up_xattr),
4876 	LSM_HOOK_INIT(dentry_create_files_as, smack_dentry_create_files_as),
4877 };
4878 
4879 
init_smack_known_list(void)4880 static __init void init_smack_known_list(void)
4881 {
4882 	/*
4883 	 * Initialize rule list locks
4884 	 */
4885 	mutex_init(&smack_known_huh.smk_rules_lock);
4886 	mutex_init(&smack_known_hat.smk_rules_lock);
4887 	mutex_init(&smack_known_floor.smk_rules_lock);
4888 	mutex_init(&smack_known_star.smk_rules_lock);
4889 	mutex_init(&smack_known_web.smk_rules_lock);
4890 	/*
4891 	 * Initialize rule lists
4892 	 */
4893 	INIT_LIST_HEAD(&smack_known_huh.smk_rules);
4894 	INIT_LIST_HEAD(&smack_known_hat.smk_rules);
4895 	INIT_LIST_HEAD(&smack_known_star.smk_rules);
4896 	INIT_LIST_HEAD(&smack_known_floor.smk_rules);
4897 	INIT_LIST_HEAD(&smack_known_web.smk_rules);
4898 	/*
4899 	 * Create the known labels list
4900 	 */
4901 	smk_insert_entry(&smack_known_huh);
4902 	smk_insert_entry(&smack_known_hat);
4903 	smk_insert_entry(&smack_known_star);
4904 	smk_insert_entry(&smack_known_floor);
4905 	smk_insert_entry(&smack_known_web);
4906 }
4907 
4908 /**
4909  * smack_init - initialize the smack system
4910  *
4911  * Returns 0 on success, -ENOMEM is there's no memory
4912  */
smack_init(void)4913 static __init int smack_init(void)
4914 {
4915 	struct cred *cred = (struct cred *) current->cred;
4916 	struct task_smack *tsp;
4917 
4918 	smack_rule_cache = KMEM_CACHE(smack_rule, 0);
4919 	if (!smack_rule_cache)
4920 		return -ENOMEM;
4921 
4922 	/*
4923 	 * Set the security state for the initial task.
4924 	 */
4925 	tsp = smack_cred(cred);
4926 	init_task_smack(tsp, &smack_known_floor, &smack_known_floor);
4927 
4928 	/*
4929 	 * Register with LSM
4930 	 */
4931 	security_add_hooks(smack_hooks, ARRAY_SIZE(smack_hooks), "smack");
4932 	smack_enabled = 1;
4933 
4934 	pr_info("Smack:  Initializing.\n");
4935 #ifdef CONFIG_SECURITY_SMACK_NETFILTER
4936 	pr_info("Smack:  Netfilter enabled.\n");
4937 #endif
4938 #ifdef SMACK_IPV6_PORT_LABELING
4939 	pr_info("Smack:  IPv6 port labeling enabled.\n");
4940 #endif
4941 #ifdef SMACK_IPV6_SECMARK_LABELING
4942 	pr_info("Smack:  IPv6 Netfilter enabled.\n");
4943 #endif
4944 
4945 	/* initialize the smack_known_list */
4946 	init_smack_known_list();
4947 
4948 	return 0;
4949 }
4950 
4951 /*
4952  * Smack requires early initialization in order to label
4953  * all processes and objects when they are created.
4954  */
4955 DEFINE_LSM(smack) = {
4956 	.name = "smack",
4957 	.flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE,
4958 	.blobs = &smack_blob_sizes,
4959 	.init = smack_init,
4960 };
4961