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