security/apparmor/capability.c

   1 /*
   2  * AppArmor security module
   3  *
   4  * This file contains AppArmor capability mediation functions
   5  *
   6  * Copyright (C) 1998-2008 Novell/SUSE
   7  * Copyright 2009-2010 Canonical Ltd.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation, version 2 of the
  12  * License.
  13  */
  14
  15 #include <linux/capability.h>
  16 #include <linux/errno.h>
  17 #include <linux/gfp.h>
  18
  19 #include "include/apparmor.h"
  20 #include "include/capability.h"
  21 #include "include/context.h"
  22 #include "include/policy.h"
  23 #include "include/audit.h"
  24
  25 /*
  26  * Table of capability names: we generate it from capabilities.h.
  27  */
  28 #include "capability_names.h"
  29
  30 struct aa_fs_entry aa_fs_entry_caps[] = {
  31         AA_FS_FILE_STRING("mask", AA_FS_CAPS_MASK),
  32         { }
  33 };
  34
  35 struct audit_cache {
  36         struct aa_profile *profile;
  37         kernel_cap_t caps;
  38 };
  39
  40 static DEFINE_PER_CPU(struct audit_cache, audit_cache);
  41
  42 /**
  43  * audit_cb - call back for capability components of audit struct
  44  * @ab - audit buffer   (NOT NULL)
  45  * @va - audit struct to audit data from  (NOT NULL)
  46  */
  47 static void audit_cb(struct audit_buffer *ab, void *va)
  48 {
  49         struct common_audit_data *sa = va;
  50         audit_log_format(ab, " capname=");
  51         audit_log_untrustedstring(ab, capability_names[sa->u.cap]);
  52 }
  53
  54 /**
  55  * audit_caps - audit a capability
  56  * @profile: profile being tested for confinement (NOT NULL)
  57  * @cap: capability tested
  58  * @error: error code returned by test
  59  *
  60  * Do auditing of capability and handle, audit/complain/kill modes switching
  61  * and duplicate message elimination.
  62  *
  63  * Returns: 0 or sa->error on success,  error code on failure
  64  */
  65 static int audit_caps(struct aa_profile *profile, int cap, int error)
  66 {
  67         struct audit_cache *ent;
  68         int type = AUDIT_APPARMOR_AUTO;
  69         struct common_audit_data sa;
  70         struct apparmor_audit_data aad = {0,};
  71         sa.type = LSM_AUDIT_DATA_CAP;
  72         sa.aad = &aad;
  73         sa.u.cap = cap;
  74         sa.aad->op = OP_CAPABLE;
  75         sa.aad->error = error;
  76
  77         if (likely(!error)) {
  78                 /* test if auditing is being forced */
  79                 if (likely((AUDIT_MODE(profile) != AUDIT_ALL) &&
  80                            !cap_raised(profile->caps.audit, cap)))
  81                         return 0;
  82                 type = AUDIT_APPARMOR_AUDIT;
  83         } else if (KILL_MODE(profile) ||
  84                    cap_raised(profile->caps.kill, cap)) {
  85                 type = AUDIT_APPARMOR_KILL;
  86         } else if (cap_raised(profile->caps.quiet, cap) &&
  87                    AUDIT_MODE(profile) != AUDIT_NOQUIET &&
  88                    AUDIT_MODE(profile) != AUDIT_ALL) {
  89                 /* quiet auditing */
  90                 return error;
  91         }
  92
  93         /* Do simple duplicate message elimination */
  94         ent = &get_cpu_var(audit_cache);
  95         if (profile == ent->profile && cap_raised(ent->caps, cap)) {
  96                 put_cpu_var(audit_cache);
  97                 if (COMPLAIN_MODE(profile))
  98                         return complain_error(error);
  99                 return error;
 100         } else {
 101                 aa_put_profile(ent->profile);
 102                 ent->profile = aa_get_profile(profile);
 103                 cap_raise(ent->caps, cap);
 104         }
 105         put_cpu_var(audit_cache);
 106
 107         return aa_audit(type, profile, GFP_ATOMIC, &sa, audit_cb);
 108 }
 109
 110 /**
 111  * profile_capable - test if profile allows use of capability @cap
 112  * @profile: profile being enforced    (NOT NULL, NOT unconfined)
 113  * @cap: capability to test if allowed
 114  *
 115  * Returns: 0 if allowed else -EPERM
 116  */
 117 static int profile_capable(struct aa_profile *profile, int cap)
 118 {
 119         return cap_raised(profile->caps.allow, cap) ? 0 : -EPERM;
 120 }
 121
 122 /**
 123  * aa_capable - test permission to use capability
 124  * @profile: profile being tested against (NOT NULL)
 125  * @cap: capability to be tested
 126  * @audit: whether an audit record should be generated
 127  *
 128  * Look up capability in profile capability set.
 129  *
 130  * Returns: 0 on success, or else an error code.
 131  */
 132 int aa_capable(struct aa_profile *profile, int cap, int audit)
 133 {
 134         int error = profile_capable(profile, cap);
 135
 136         if (!audit) {
 137                 if (COMPLAIN_MODE(profile))
 138                         return complain_error(error);
 139                 return error;
 140         }
 141
 142         return audit_caps(profile, cap, error);
 143 }