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 */
26 struct avc_entry;
27
28 struct task_struct;
29 struct inode;
30 struct sock;
31 struct sk_buff;
32
33 /*
34 * AVC statistics
35 */
36 struct 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 */
47 struct 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
61 void __init avc_init(void);
62
avc_audit_required(u32 requested,struct av_decision * avd,int result,u32 auditdeny,u32 * deniedp)63 static 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
99 int 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 */
avc_audit(u32 ssid,u32 tsid,u16 tclass,u32 requested,struct av_decision * avd,int result,struct common_audit_data * a)122 static 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 */
139 int avc_has_perm_noaudit(u32 ssid, u32 tsid,
140 u16 tclass, u32 requested,
141 unsigned flags,
142 struct av_decision *avd);
143
144 int avc_has_perm(u32 ssid, u32 tsid,
145 u16 tclass, u32 requested,
146 struct common_audit_data *auditdata);
147
148 int avc_has_extended_perms(u32 ssid, u32 tsid, u16 tclass, u32 requested,
149 u8 driver, u8 perm, struct common_audit_data *ad);
150
151
152 u32 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
164 int avc_add_callback(int (*callback)(u32 event), u32 events);
165
166 /* Exported to selinuxfs */
167 int avc_get_hash_stats(char *page);
168 unsigned int avc_get_cache_threshold(void);
169 void avc_set_cache_threshold(unsigned int cache_threshold);
170
171 #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
172 DECLARE_PER_CPU(struct avc_cache_stats, avc_cache_stats);
173 #endif
174
175 #endif /* _SELINUX_AVC_H_ */
176
177