xref: /linux/security/selinux/include/avc.h (revision 06d07429858317ded2db7986113a9e0129cd599b)
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 
avc_audit_required(u32 requested,struct av_decision * avd,int result,u32 auditdeny,u32 * deniedp)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  */
avc_audit(u32 ssid,u32 tsid,u16 tclass,u32 requested,struct av_decision * avd,int result,struct common_audit_data * a)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