security/selinux/include/avc.h

   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 #ifdef CONFIG_SECURITY_SELINUX_DEVELOP
  24 extern int selinux_enforcing;
  25 #else
  26 #define selinux_enforcing 1
  27 #endif
  28
  29 /*
  30  * An entry in the AVC.
  31  */
  32 struct avc_entry;
  33
  34 struct task_struct;
  35 struct inode;
  36 struct sock;
  37 struct sk_buff;
  38
  39 /*
  40  * AVC statistics
  41  */
  42 struct avc_cache_stats {
  43         unsigned int lookups;
  44         unsigned int misses;
  45         unsigned int allocations;
  46         unsigned int reclaims;
  47         unsigned int frees;
  48 };
  49
  50 /*
  51  * We only need this data after we have decided to send an audit message.
  52  */
  53 struct selinux_audit_data {
  54         u32 ssid;
  55         u32 tsid;
  56         u16 tclass;
  57         u32 requested;
  58         u32 audited;
  59         u32 denied;
  60         int result;
  61 };
  62
  63 /*
  64  * AVC operations
  65  */
  66
  67 void __init avc_init(void);
  68
  69 static inline u32 avc_audit_required(u32 requested,
  70                               struct av_decision *avd,
  71                               int result,
  72                               u32 auditdeny,
  73                               u32 *deniedp)
  74 {
  75         u32 denied, audited;
  76         denied = requested & ~avd->allowed;
  77         if (unlikely(denied)) {
  78                 audited = denied & avd->auditdeny;
  79                 /*
  80                  * auditdeny is TRICKY!  Setting a bit in
  81                  * this field means that ANY denials should NOT be audited if
  82                  * the policy contains an explicit dontaudit rule for that
  83                  * permission.  Take notice that this is unrelated to the
  84                  * actual permissions that were denied.  As an example lets
  85                  * assume:
  86                  *
  87                  * denied == READ
  88                  * avd.auditdeny & ACCESS == 0 (not set means explicit rule)
  89                  * auditdeny & ACCESS == 1
  90                  *
  91                  * We will NOT audit the denial even though the denied
  92                  * permission was READ and the auditdeny checks were for
  93                  * ACCESS
  94                  */
  95                 if (auditdeny && !(auditdeny & avd->auditdeny))
  96                         audited = 0;
  97         } else if (result)
  98                 audited = denied = requested;
  99         else
 100                 audited = requested & avd->auditallow;
 101         *deniedp = denied;
 102         return audited;
 103 }
 104
 105 int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass,
 106                    u32 requested, u32 audited, u32 denied, int result,
 107                    struct common_audit_data *a,
 108                    unsigned flags);
 109
 110 /**
 111  * avc_audit - Audit the granting or denial of permissions.
 112  * @ssid: source security identifier
 113  * @tsid: target security identifier
 114  * @tclass: target security class
 115  * @requested: requested permissions
 116  * @avd: access vector decisions
 117  * @result: result from avc_has_perm_noaudit
 118  * @a:  auxiliary audit data
 119  * @flags: VFS walk flags
 120  *
 121  * Audit the granting or denial of permissions in accordance
 122  * with the policy.  This function is typically called by
 123  * avc_has_perm() after a permission check, but can also be
 124  * called directly by callers who use avc_has_perm_noaudit()
 125  * in order to separate the permission check from the auditing.
 126  * For example, this separation is useful when the permission check must
 127  * be performed under a lock, to allow the lock to be released
 128  * before calling the auditing code.
 129  */
 130 static inline int avc_audit(u32 ssid, u32 tsid,
 131                             u16 tclass, u32 requested,
 132                             struct av_decision *avd,
 133                             int result,
 134                             struct common_audit_data *a,
 135                             int flags)
 136 {
 137         u32 audited, denied;
 138         audited = avc_audit_required(requested, avd, result, 0, &denied);
 139         if (likely(!audited))
 140                 return 0;
 141         return slow_avc_audit(ssid, tsid, tclass,
 142                               requested, audited, denied, result,
 143                               a, flags);
 144 }
 145
 146 #define AVC_STRICT 1 /* Ignore permissive mode. */
 147 #define AVC_EXTENDED_PERMS 2    /* update extended permissions */
 148 int avc_has_perm_noaudit(u32 ssid, u32 tsid,
 149                          u16 tclass, u32 requested,
 150                          unsigned flags,
 151                          struct av_decision *avd);
 152
 153 int avc_has_perm(u32 ssid, u32 tsid,
 154                  u16 tclass, u32 requested,
 155                  struct common_audit_data *auditdata);
 156 int avc_has_perm_flags(u32 ssid, u32 tsid,
 157                        u16 tclass, u32 requested,
 158                        struct common_audit_data *auditdata,
 159                        int flags);
 160
 161 int avc_has_extended_perms(u32 ssid, u32 tsid, u16 tclass, u32 requested,
 162                 u8 driver, u8 perm, struct common_audit_data *ad);
 163
 164
 165 u32 avc_policy_seqno(void);
 166
 167 #define AVC_CALLBACK_GRANT              1
 168 #define AVC_CALLBACK_TRY_REVOKE         2
 169 #define AVC_CALLBACK_REVOKE             4
 170 #define AVC_CALLBACK_RESET              8
 171 #define AVC_CALLBACK_AUDITALLOW_ENABLE  16
 172 #define AVC_CALLBACK_AUDITALLOW_DISABLE 32
 173 #define AVC_CALLBACK_AUDITDENY_ENABLE   64
 174 #define AVC_CALLBACK_AUDITDENY_DISABLE  128
 175 #define AVC_CALLBACK_ADD_XPERMS         256
 176
 177 int avc_add_callback(int (*callback)(u32 event), u32 events);
 178
 179 /* Exported to selinuxfs */
 180 int avc_get_hash_stats(char *page);
 181 extern unsigned int avc_cache_threshold;
 182
 183 /* Attempt to free avc node cache */
 184 void avc_disable(void);
 185
 186 #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
 187 DECLARE_PER_CPU(struct avc_cache_stats, avc_cache_stats);
 188 #endif
 189
 190 #endif /* _SELINUX_AVC_H_ */
 191