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 */
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 struct selinux_state *state;
56 };
57
58 /*
59 * AVC operations
60 */
61
62 void __init avc_init(void);
63
avc_audit_required(u32 requested,struct av_decision * avd,int result,u32 auditdeny,u32 * deniedp)64 static 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
100 int 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 */
avc_audit(struct selinux_state * state,u32 ssid,u32 tsid,u16 tclass,u32 requested,struct av_decision * avd,int result,struct common_audit_data * a,int flags)125 static 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 */
148 int 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
154 int avc_has_perm(struct selinux_state *state,
155 u32 ssid, u32 tsid,
156 u16 tclass, u32 requested,
157 struct common_audit_data *auditdata);
158 int 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
164 int 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
169 u32 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
181 int avc_add_callback(int (*callback)(u32 event), u32 events);
182
183 /* Exported to selinuxfs */
184 struct selinux_avc;
185 int avc_get_hash_stats(struct selinux_avc *avc, char *page);
186 unsigned int avc_get_cache_threshold(struct selinux_avc *avc);
187 void avc_set_cache_threshold(struct selinux_avc *avc,
188 unsigned int cache_threshold);
189
190 /* Attempt to free avc node cache */
191 void avc_disable(void);
192
193 #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
194 DECLARE_PER_CPU(struct avc_cache_stats, avc_cache_stats);
195 #endif
196
197 #endif /* _SELINUX_AVC_H_ */
198
199
