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	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
97int 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 */
119static 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 */
133int avc_has_perm_noaudit(u32 ssid, u32 tsid, u16 tclass, u32 requested,
134			 unsigned int flags, struct av_decision *avd);
135
136int avc_has_perm(u32 ssid, u32 tsid, u16 tclass, u32 requested,
137		 struct common_audit_data *auditdata);
138
139int avc_has_extended_perms(u32 ssid, u32 tsid, u16 tclass, u32 requested,
140			   u8 driver, u8 perm, struct common_audit_data *ad);
141
142u32 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
154int avc_add_callback(int (*callback)(u32 event), u32 events);
155
156/* Exported to selinuxfs */
157int avc_get_hash_stats(char *page);
158unsigned int avc_get_cache_threshold(void);
159void avc_set_cache_threshold(unsigned int cache_threshold);
160
161#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
162DECLARE_PER_CPU(struct avc_cache_stats, avc_cache_stats);
163#endif
164
165#endif /* _SELINUX_AVC_H_ */
166