LXR linux/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
  23extern int selinux_enforcing;
  24#else
  25#define selinux_enforcing 1
  26#endif
  27
  28/*
  29 * An entry in the AVC.
  30 */
  31struct avc_entry;
  32
  33struct task_struct;
  34struct inode;
  35struct sock;
  36struct sk_buff;
  37
  38/*
  39 * AVC statistics
  40 */
  41struct 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 */
  52struct 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
  66void __init avc_init(void);
  67
  68static 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
 104int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass,
 105                   u32 requested, u32 audited, u32 denied, int result,
 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 */
 129static 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                            int flags)
 135{
 136        u32 audited, denied;
 137        audited = avc_audit_required(requested, avd, result, 0, &denied);
 138        if (likely(!audited))
 139                return 0;
 140        return slow_avc_audit(ssid, tsid, tclass,
 141                              requested, audited, denied, result,
 142                              a, flags);
 143}
 144
 145#define AVC_STRICT 1 /* Ignore permissive mode. */
 146#define AVC_EXTENDED_PERMS 2    /* update extended permissions */
 147int avc_has_perm_noaudit(u32 ssid, u32 tsid,
 148                         u16 tclass, u32 requested,
 149                         unsigned flags,
 150                         struct av_decision *avd);
 151
 152int avc_has_perm(u32 ssid, u32 tsid,
 153                 u16 tclass, u32 requested,
 154                 struct common_audit_data *auditdata);
 155int avc_has_perm_flags(u32 ssid, u32 tsid,
 156                       u16 tclass, u32 requested,
 157                       struct common_audit_data *auditdata,
 158                       int flags);
 159
 160int avc_has_extended_perms(u32 ssid, u32 tsid, u16 tclass, u32 requested,
 161                u8 driver, u8 perm, struct common_audit_data *ad);
 162
 163
 164u32 avc_policy_seqno(void);
 165
 166#define AVC_CALLBACK_GRANT              1
 167#define AVC_CALLBACK_TRY_REVOKE         2
 168#define AVC_CALLBACK_REVOKE             4
 169#define AVC_CALLBACK_RESET              8
 170#define AVC_CALLBACK_AUDITALLOW_ENABLE  16
 171#define AVC_CALLBACK_AUDITALLOW_DISABLE 32
 172#define AVC_CALLBACK_AUDITDENY_ENABLE   64
 173#define AVC_CALLBACK_AUDITDENY_DISABLE  128
 174#define AVC_CALLBACK_ADD_XPERMS         256
 175
 176int avc_add_callback(int (*callback)(u32 event), u32 events);
 177
 178/* Exported to selinuxfs */
 179int avc_get_hash_stats(char *page);
 180extern unsigned int avc_cache_threshold;
 181
 182/* Attempt to free avc node cache */
 183void avc_disable(void);
 184
 185#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
 186DECLARE_PER_CPU(struct avc_cache_stats, avc_cache_stats);
 187#endif
 188
 189#endif /* _SELINUX_AVC_H_ */
 190
 191