1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Access vector cache interface for object managers.
4 *
5 * Author : Stephen Smalley, <stephen.smalley.work@gmail.com>
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} __randomize_layout;
56
57/*
58 * AVC operations
59 */
60
61void __init avc_init(void);
62
63static inline u32 avc_audit_required(u32 requested,
64			      struct av_decision *avd,
65			      int result,
66			      u32 auditdeny,
67			      u32 *deniedp)
68{
69	u32 denied, audited;
70	denied = requested & ~avd->allowed;
71	if (unlikely(denied)) {
72		audited = denied & avd->auditdeny;
73		/*
74		 * auditdeny is TRICKY!  Setting a bit in
75		 * this field means that ANY denials should NOT be audited if
76		 * the policy contains an explicit dontaudit rule for that
77		 * permission.  Take notice that this is unrelated to the
78		 * actual permissions that were denied.  As an example lets
79		 * assume:
80		 *
81		 * denied == READ
82		 * avd.auditdeny & ACCESS == 0 (not set means explicit rule)
83		 * auditdeny & ACCESS == 1
84		 *
85		 * We will NOT audit the denial even though the denied
86		 * permission was READ and the auditdeny checks were for
87		 * ACCESS
88		 */
89		if (auditdeny && !(auditdeny & avd->auditdeny))
90			audited = 0;
91	} else if (result)
92		audited = denied = requested;
93	else
94		audited = requested & avd->auditallow;
95	*deniedp = denied;
96	return audited;
97}
98
99int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass,
100		   u32 requested, u32 audited, u32 denied, int result,
101		   struct common_audit_data *a);
102
103/**
104 * avc_audit - Audit the granting or denial of permissions.
105 * @ssid: source security identifier
106 * @tsid: target security identifier
107 * @tclass: target security class
108 * @requested: requested permissions
109 * @avd: access vector decisions
110 * @result: result from avc_has_perm_noaudit
111 * @a:  auxiliary audit data
112 *
113 * Audit the granting or denial of permissions in accordance
114 * with the policy.  This function is typically called by
115 * avc_has_perm() after a permission check, but can also be
116 * called directly by callers who use avc_has_perm_noaudit()
117 * in order to separate the permission check from the auditing.
118 * For example, this separation is useful when the permission check must
119 * be performed under a lock, to allow the lock to be released
120 * before calling the auditing code.
121 */
122static inline int avc_audit(u32 ssid, u32 tsid,
123			    u16 tclass, u32 requested,
124			    struct av_decision *avd,
125			    int result,
126			    struct common_audit_data *a)
127{
128	u32 audited, denied;
129	audited = avc_audit_required(requested, avd, result, 0, &denied);
130	if (likely(!audited))
131		return 0;
132	return slow_avc_audit(ssid, tsid, tclass,
133			      requested, audited, denied, result,
134			      a);
135}
136
137#define AVC_STRICT 1 /* Ignore permissive mode. */
138#define AVC_EXTENDED_PERMS 2	/* update extended permissions */
139int avc_has_perm_noaudit(u32 ssid, u32 tsid,
140			 u16 tclass, u32 requested,
141			 unsigned flags,
142			 struct av_decision *avd);
143
144int avc_has_perm(u32 ssid, u32 tsid,
145		 u16 tclass, u32 requested,
146		 struct common_audit_data *auditdata);
147
148int avc_has_extended_perms(u32 ssid, u32 tsid, u16 tclass, u32 requested,
149			   u8 driver, u8 perm, struct common_audit_data *ad);
150
151
152u32 avc_policy_seqno(void);
153
154#define AVC_CALLBACK_GRANT		1
155#define AVC_CALLBACK_TRY_REVOKE		2
156#define AVC_CALLBACK_REVOKE		4
157#define AVC_CALLBACK_RESET		8
158#define AVC_CALLBACK_AUDITALLOW_ENABLE	16
159#define AVC_CALLBACK_AUDITALLOW_DISABLE	32
160#define AVC_CALLBACK_AUDITDENY_ENABLE	64
161#define AVC_CALLBACK_AUDITDENY_DISABLE	128
162#define AVC_CALLBACK_ADD_XPERMS		256
163
164int avc_add_callback(int (*callback)(u32 event), u32 events);
165
166/* Exported to selinuxfs */
167int avc_get_hash_stats(char *page);
168unsigned int avc_get_cache_threshold(void);
169void avc_set_cache_threshold(unsigned int cache_threshold);
170
171#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
172DECLARE_PER_CPU(struct avc_cache_stats, avc_cache_stats);
173#endif
174
175#endif /* _SELINUX_AVC_H_ */
176
177