avc.h

  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, 0, &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_ */