1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Access vector cache interface for object managers.
4 *
5 * Author : Stephen Smalley, <sds@tycho.nsa.gov>
6 */
7#ifndef _SELINUX_AVC_H_
8#define _SELINUX_AVC_H_
9
10#include <linux/stddef.h>
11#include <linux/errno.h>
12#include <linux/kernel.h>
13#include <linux/kdev_t.h>
14#include <linux/spinlock.h>
15#include <linux/init.h>
16#include <linux/audit.h>
17#include <linux/lsm_audit.h>
18#include <linux/in6.h>
19#include "flask.h"
20#include "av_permissions.h"
21#include "security.h"
22
23/*
24 * An entry in the AVC.
25 */
26struct avc_entry;
27
28struct task_struct;
29struct inode;
30struct sock;
31struct sk_buff;
32
33/*
34 * AVC statistics
35 */
36struct avc_cache_stats {
37	unsigned int lookups;
38	unsigned int misses;
39	unsigned int allocations;
40	unsigned int reclaims;
41	unsigned int frees;
42};
43
44/*
45 * We only need this data after we have decided to send an audit message.
46 */
47struct selinux_audit_data {
48	u32 ssid;
49	u32 tsid;
50	u16 tclass;
51	u32 requested;
52	u32 audited;
53	u32 denied;
54	int result;
55	struct selinux_state *state;
56};
57
58/*
59 * AVC operations
60 */
61
62void __init avc_init(void);
63
64static inline u32 avc_audit_required(u32 requested,
65			      struct av_decision *avd,
66			      int result,
67			      u32 auditdeny,
68			      u32 *deniedp)
69{
70	u32 denied, audited;
71	denied = requested & ~avd->allowed;
72	if (unlikely(denied)) {
73		audited = denied & avd->auditdeny;
74		/*
75		 * auditdeny is TRICKY!  Setting a bit in
76		 * this field means that ANY denials should NOT be audited if
77		 * the policy contains an explicit dontaudit rule for that
78		 * permission.  Take notice that this is unrelated to the
79		 * actual permissions that were denied.  As an example lets
80		 * assume:
81		 *
82		 * denied == READ
83		 * avd.auditdeny & ACCESS == 0 (not set means explicit rule)
84		 * auditdeny & ACCESS == 1
85		 *
86		 * We will NOT audit the denial even though the denied
87		 * permission was READ and the auditdeny checks were for
88		 * ACCESS
89		 */
90		if (auditdeny && !(auditdeny & avd->auditdeny))
91			audited = 0;
92	} else if (result)
93		audited = denied = requested;
94	else
95		audited = requested & avd->auditallow;
96	*deniedp = denied;
97	return audited;
98}
99
100int slow_avc_audit(struct selinux_state *state,
101		   u32 ssid, u32 tsid, u16 tclass,
102		   u32 requested, u32 audited, u32 denied, int result,
103		   struct common_audit_data *a);
104
105/**
106 * avc_audit - Audit the granting or denial of permissions.
107 * @ssid: source security identifier
108 * @tsid: target security identifier
109 * @tclass: target security class
110 * @requested: requested permissions
111 * @avd: access vector decisions
112 * @result: result from avc_has_perm_noaudit
113 * @a:  auxiliary audit data
114 * @flags: VFS walk flags
115 *
116 * Audit the granting or denial of permissions in accordance
117 * with the policy.  This function is typically called by
118 * avc_has_perm() after a permission check, but can also be
119 * called directly by callers who use avc_has_perm_noaudit()
120 * in order to separate the permission check from the auditing.
121 * For example, this separation is useful when the permission check must
122 * be performed under a lock, to allow the lock to be released
123 * before calling the auditing code.
124 */
125static inline int avc_audit(struct selinux_state *state,
126			    u32 ssid, u32 tsid,
127			    u16 tclass, u32 requested,
128			    struct av_decision *avd,
129			    int result,
130			    struct common_audit_data *a,
131			    int flags)
132{
133	u32 audited, denied;
134	audited = avc_audit_required(requested, avd, result, 0, &denied);
135	if (likely(!audited))
136		return 0;
137	/* fall back to ref-walk if we have to generate audit */
138	if (flags & MAY_NOT_BLOCK)
139		return -ECHILD;
140	return slow_avc_audit(state, ssid, tsid, tclass,
141			      requested, audited, denied, result,
142			      a);
143}
144
145#define AVC_STRICT 1 /* Ignore permissive mode. */
146#define AVC_EXTENDED_PERMS 2	/* update extended permissions */
147#define AVC_NONBLOCKING    4	/* non blocking */
148int avc_has_perm_noaudit(struct selinux_state *state,
149			 u32 ssid, u32 tsid,
150			 u16 tclass, u32 requested,
151			 unsigned flags,
152			 struct av_decision *avd);
153
154int avc_has_perm(struct selinux_state *state,
155		 u32 ssid, u32 tsid,
156		 u16 tclass, u32 requested,
157		 struct common_audit_data *auditdata);
158int avc_has_perm_flags(struct selinux_state *state,
159		       u32 ssid, u32 tsid,
160		       u16 tclass, u32 requested,
161		       struct common_audit_data *auditdata,
162		       int flags);
163
164int avc_has_extended_perms(struct selinux_state *state,
165			   u32 ssid, u32 tsid, u16 tclass, u32 requested,
166			   u8 driver, u8 perm, struct common_audit_data *ad);
167
168
169u32 avc_policy_seqno(struct selinux_state *state);
170
171#define AVC_CALLBACK_GRANT		1
172#define AVC_CALLBACK_TRY_REVOKE		2
173#define AVC_CALLBACK_REVOKE		4
174#define AVC_CALLBACK_RESET		8
175#define AVC_CALLBACK_AUDITALLOW_ENABLE	16
176#define AVC_CALLBACK_AUDITALLOW_DISABLE	32
177#define AVC_CALLBACK_AUDITDENY_ENABLE	64
178#define AVC_CALLBACK_AUDITDENY_DISABLE	128
179#define AVC_CALLBACK_ADD_XPERMS		256
180
181int avc_add_callback(int (*callback)(u32 event), u32 events);
182
183/* Exported to selinuxfs */
184struct selinux_avc;
185int avc_get_hash_stats(struct selinux_avc *avc, char *page);
186unsigned int avc_get_cache_threshold(struct selinux_avc *avc);
187void avc_set_cache_threshold(struct selinux_avc *avc,
188			     unsigned int cache_threshold);
189
190/* Attempt to free avc node cache */
191void avc_disable(void);
192
193#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
194DECLARE_PER_CPU(struct avc_cache_stats, avc_cache_stats);
195#endif
196
197#endif /* _SELINUX_AVC_H_ */
198
199