security/selinux/include/avc.h

   1 /*
   2  * Access vector cache interface for object managers.
   3  *
   4  * Author : Stephen Smalley, <sds@epoch.ncsc.mil>
   5  */
   6 #ifndef _SELINUX_AVC_H_
   7 #define _SELINUX_AVC_H_
   8
   9 #include <linux/stddef.h>
  10 #include <linux/errno.h>
  11 #include <linux/kernel.h>
  12 #include <linux/kdev_t.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/init.h>
  15 #include <linux/audit.h>
  16 #include <linux/lsm_audit.h>
  17 #include <linux/in6.h>
  18 #include "flask.h"
  19 #include "av_permissions.h"
  20 #include "security.h"
  21
  22 #ifdef CONFIG_SECURITY_SELINUX_DEVELOP
  23 extern int selinux_enforcing;
  24 #else
  25 #define selinux_enforcing 1
  26 #endif
  27
  28 /*
  29  * An entry in the AVC.
  30  */
  31 struct avc_entry;
  32
  33 struct task_struct;
  34 struct inode;
  35 struct sock;
  36 struct sk_buff;
  37
  38 /*
  39  * AVC statistics
  40  */
  41 struct avc_cache_stats {
  42         unsigned int lookups;
  43         unsigned int misses;
  44         unsigned int allocations;
  45         unsigned int reclaims;
  46         unsigned int frees;
  47 };
  48
  49 /*
  50  * We only need this data after we have decided to send an audit message.
  51  */
  52 struct selinux_audit_data {
  53         u32 ssid;
  54         u32 tsid;
  55         u16 tclass;
  56         u32 requested;
  57         u32 audited;
  58         u32 denied;
  59         int result;
  60 };
  61
  62 /*
  63  * AVC operations
  64  */
  65
  66 void __init avc_init(void);
  67
  68 static inline u32 avc_audit_required(u32 requested,
  69                               struct av_decision *avd,
  70                               int result,
  71                               u32 auditdeny,
  72                               u32 *deniedp)
  73 {
  74         u32 denied, audited;
  75         denied = requested & ~avd->allowed;
  76         if (unlikely(denied)) {
  77                 audited = denied & avd->auditdeny;
  78                 /*
  79                  * auditdeny is TRICKY!  Setting a bit in
  80                  * this field means that ANY denials should NOT be audited if
  81                  * the policy contains an explicit dontaudit rule for that
  82                  * permission.  Take notice that this is unrelated to the
  83                  * actual permissions that were denied.  As an example lets
  84                  * assume:
  85                  *
  86                  * denied == READ
  87                  * avd.auditdeny & ACCESS == 0 (not set means explicit rule)
  88                  * auditdeny & ACCESS == 1
  89                  *
  90                  * We will NOT audit the denial even though the denied
  91                  * permission was READ and the auditdeny checks were for
  92                  * ACCESS
  93                  */
  94                 if (auditdeny && !(auditdeny & avd->auditdeny))
  95                         audited = 0;
  96         } else if (result)
  97                 audited = denied = requested;
  98         else
  99                 audited = requested & avd->auditallow;
 100         *deniedp = denied;
 101         return audited;
 102 }
 103
 104 int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass,
 105                    u32 requested, u32 audited, u32 denied,
 106                    struct common_audit_data *a,
 107                    unsigned flags);
 108
 109 /**
 110  * avc_audit - Audit the granting or denial of permissions.
 111  * @ssid: source security identifier
 112  * @tsid: target security identifier
 113  * @tclass: target security class
 114  * @requested: requested permissions
 115  * @avd: access vector decisions
 116  * @result: result from avc_has_perm_noaudit
 117  * @a:  auxiliary audit data
 118  * @flags: VFS walk flags
 119  *
 120  * Audit the granting or denial of permissions in accordance
 121  * with the policy.  This function is typically called by
 122  * avc_has_perm() after a permission check, but can also be
 123  * called directly by callers who use avc_has_perm_noaudit()
 124  * in order to separate the permission check from the auditing.
 125  * For example, this separation is useful when the permission check must
 126  * be performed under a lock, to allow the lock to be released
 127  * before calling the auditing code.
 128  */
 129 static inline int avc_audit(u32 ssid, u32 tsid,
 130                             u16 tclass, u32 requested,
 131                             struct av_decision *avd,
 132                             int result,
 133                             struct common_audit_data *a)
 134 {
 135         u32 audited, denied;
 136         audited = avc_audit_required(requested, avd, result, 0, &denied);
 137         if (likely(!audited))
 138                 return 0;
 139         return slow_avc_audit(ssid, tsid, tclass,
 140                               requested, audited, denied,
 141                               a, 0);
 142 }
 143
 144 #define AVC_STRICT 1 /* Ignore permissive mode. */
 145 int avc_has_perm_noaudit(u32 ssid, u32 tsid,
 146                          u16 tclass, u32 requested,
 147                          unsigned flags,
 148                          struct av_decision *avd);
 149
 150 int avc_has_perm(u32 ssid, u32 tsid,
 151                  u16 tclass, u32 requested,
 152                  struct common_audit_data *auditdata);
 153
 154 u32 avc_policy_seqno(void);
 155
 156 #define AVC_CALLBACK_GRANT              1
 157 #define AVC_CALLBACK_TRY_REVOKE         2
 158 #define AVC_CALLBACK_REVOKE             4
 159 #define AVC_CALLBACK_RESET              8
 160 #define AVC_CALLBACK_AUDITALLOW_ENABLE  16
 161 #define AVC_CALLBACK_AUDITALLOW_DISABLE 32
 162 #define AVC_CALLBACK_AUDITDENY_ENABLE   64
 163 #define AVC_CALLBACK_AUDITDENY_DISABLE  128
 164
 165 int avc_add_callback(int (*callback)(u32 event), u32 events);
 166
 167 /* Exported to selinuxfs */
 168 int avc_get_hash_stats(char *page);
 169 extern unsigned int avc_cache_threshold;
 170
 171 /* Attempt to free avc node cache */
 172 void avc_disable(void);
 173
 174 #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
 175 DECLARE_PER_CPU(struct avc_cache_stats, avc_cache_stats);
 176 #endif
 177
 178 #endif /* _SELINUX_AVC_H_ */
 179