LXR linux/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
  30struct aa_fs_entry aa_fs_entry_caps[] = {
  31        AA_FS_FILE_STRING("mask", AA_FS_CAPS_MASK),
  32        { }
  33};
  34
  35struct audit_cache {
  36        struct aa_profile *profile;
  37        kernel_cap_t caps;
  38};
  39
  40static 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 */
  47static 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 */
  65static 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 */
 117static 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 */
 132int 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}
 144