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 */
27struct avc_entry;
28
29struct task_struct;
30struct inode;
31struct sock;
32struct sk_buff;
33
34/*
35 * AVC statistics
36 */
37struct 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 */
48struct 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
62void __init avc_init(void);
63
64static inline u32 avc_audit_required(u32 requested, struct av_decision *avd,
65 int result, u32 auditdeny, u32 *deniedp)
66{
67 u32 denied, audited;
68
69 if (avd->flags & AVD_FLAGS_NEVERAUDIT)
70 return 0;
71
72 denied = requested & ~avd->allowed;
73 if (unlikely(denied)) {
74 audited = denied & avd->auditdeny;
75 /*
76 * auditdeny is TRICKY! Setting a bit in
77 * this field means that ANY denials should NOT be audited if
78 * the policy contains an explicit dontaudit rule for that
79 * permission. Take notice that this is unrelated to the
80 * actual permissions that were denied. As an example lets
81 * assume:
82 *
83 * denied == READ
84 * avd.auditdeny & ACCESS == 0 (not set means explicit rule)
85 * auditdeny & ACCESS == 1
86 *
87 * We will NOT audit the denial even though the denied
88 * permission was READ and the auditdeny checks were for
89 * ACCESS
90 */
91 if (auditdeny && !(auditdeny & avd->auditdeny))
92 audited = 0;
93 } else if (result)
94 audited = denied = requested;
95 else
96 audited = requested & avd->auditallow;
97 *deniedp = denied;
98 return audited;
99}
100
101int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass, u32 requested, u32 audited,
102 u32 denied, int result, struct common_audit_data *a);
103
104/**
105 * avc_audit - Audit the granting or denial of permissions.
106 * @ssid: source security identifier
107 * @tsid: target security identifier
108 * @tclass: target security class
109 * @requested: requested permissions
110 * @avd: access vector decisions
111 * @result: result from avc_has_perm_noaudit
112 * @a: auxiliary audit data
113 *
114 * Audit the granting or denial of permissions in accordance
115 * with the policy. This function is typically called by
116 * avc_has_perm() after a permission check, but can also be
117 * called directly by callers who use avc_has_perm_noaudit()
118 * in order to separate the permission check from the auditing.
119 * For example, this separation is useful when the permission check must
120 * be performed under a lock, to allow the lock to be released
121 * before calling the auditing code.
122 */
123static inline int avc_audit(u32 ssid, u32 tsid, u16 tclass, u32 requested,
124 struct av_decision *avd, int result,
125 struct common_audit_data *a)
126{
127 u32 audited, denied;
128 audited = avc_audit_required(requested, avd, result, auditdeny: 0, deniedp: &denied);
129 if (likely(!audited))
130 return 0;
131 return slow_avc_audit(ssid, tsid, tclass, requested, audited, denied,
132 result, a);
133}
134
135#define AVC_STRICT 1 /* Ignore permissive mode. */
136#define AVC_EXTENDED_PERMS 2 /* update extended permissions */
137int avc_has_perm_noaudit(u32 ssid, u32 tsid, u16 tclass, u32 requested,
138 unsigned int flags, struct av_decision *avd);
139
140int avc_has_perm(u32 ssid, u32 tsid, u16 tclass, u32 requested,
141 struct common_audit_data *auditdata);
142
143#define AVC_EXT_IOCTL (1 << 0) /* Cache entry for an ioctl extended permission */
144#define AVC_EXT_NLMSG (1 << 1) /* Cache entry for an nlmsg extended permission */
145int avc_has_extended_perms(u32 ssid, u32 tsid, u16 tclass, u32 requested,
146 u8 driver, u8 base_perm, u8 perm,
147 struct common_audit_data *ad);
148
149u32 avc_policy_seqno(void);
150
151#define AVC_CALLBACK_GRANT 1
152#define AVC_CALLBACK_TRY_REVOKE 2
153#define AVC_CALLBACK_REVOKE 4
154#define AVC_CALLBACK_RESET 8
155#define AVC_CALLBACK_AUDITALLOW_ENABLE 16
156#define AVC_CALLBACK_AUDITALLOW_DISABLE 32
157#define AVC_CALLBACK_AUDITDENY_ENABLE 64
158#define AVC_CALLBACK_AUDITDENY_DISABLE 128
159#define AVC_CALLBACK_ADD_XPERMS 256
160
161int avc_add_callback(int (*callback)(u32 event), u32 events);
162
163/* Exported to selinuxfs */
164int avc_get_hash_stats(char *page);
165unsigned int avc_get_cache_threshold(void);
166void avc_set_cache_threshold(unsigned int cache_threshold);
167
168#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
169DECLARE_PER_CPU(struct avc_cache_stats, avc_cache_stats);
170#endif
171
172#endif /* _SELINUX_AVC_H_ */
173