capability.c
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/*
* AppArmor security module
*
* This file contains AppArmor capability mediation functions
*
* Copyright (C) 1998-2008 Novell/SUSE
* Copyright 2009-2010 Canonical Ltd.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2 of the
* License.
*/
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/gfp.h>
#include "include/apparmor.h"
#include "include/capability.h"
#include "include/context.h"
#include "include/policy.h"
#include "include/audit.h"
/*
* Table of capability names: we generate it from capabilities.h.
*/
#include "capability_names.h"
struct aa_fs_entry aa_fs_entry_caps[] = {
AA_FS_FILE_STRING("mask", AA_FS_CAPS_MASK),
{ }
};
struct audit_cache {
struct aa_profile *profile;
kernel_cap_t caps;
};
static DEFINE_PER_CPU(struct audit_cache, audit_cache);
/**
* audit_cb - call back for capability components of audit struct
* @ab - audit buffer (NOT NULL)
* @va - audit struct to audit data from (NOT NULL)
*/
static void audit_cb(struct audit_buffer *ab, void *va)
{
struct common_audit_data *sa = va;
audit_log_format(ab, " capname=");
audit_log_untrustedstring(ab, capability_names[sa->u.cap]);
}
/**
* audit_caps - audit a capability
* @profile: profile being tested for confinement (NOT NULL)
* @cap: capability tested
* @error: error code returned by test
*
* Do auditing of capability and handle, audit/complain/kill modes switching
* and duplicate message elimination.
*
* Returns: 0 or sa->error on success, error code on failure
*/
static int audit_caps(struct aa_profile *profile, int cap, int error)
{
struct audit_cache *ent;
int type = AUDIT_APPARMOR_AUTO;
struct common_audit_data sa;
struct apparmor_audit_data aad = {0,};
sa.type = LSM_AUDIT_DATA_CAP;
sa.aad = &aad;
sa.u.cap = cap;
sa.aad->op = OP_CAPABLE;
sa.aad->error = error;
if (likely(!error)) {
/* test if auditing is being forced */
if (likely((AUDIT_MODE(profile) != AUDIT_ALL) &&
!cap_raised(profile->caps.audit, cap)))
return 0;
type = AUDIT_APPARMOR_AUDIT;
} else if (KILL_MODE(profile) ||
cap_raised(profile->caps.kill, cap)) {
type = AUDIT_APPARMOR_KILL;
} else if (cap_raised(profile->caps.quiet, cap) &&
AUDIT_MODE(profile) != AUDIT_NOQUIET &&
AUDIT_MODE(profile) != AUDIT_ALL) {
/* quiet auditing */
return error;
}
/* Do simple duplicate message elimination */
ent = &get_cpu_var(audit_cache);
if (profile == ent->profile && cap_raised(ent->caps, cap)) {
put_cpu_var(audit_cache);
if (COMPLAIN_MODE(profile))
return complain_error(error);
return error;
} else {
aa_put_profile(ent->profile);
ent->profile = aa_get_profile(profile);
cap_raise(ent->caps, cap);
}
put_cpu_var(audit_cache);
return aa_audit(type, profile, GFP_ATOMIC, &sa, audit_cb);
}
/**
* profile_capable - test if profile allows use of capability @cap
* @profile: profile being enforced (NOT NULL, NOT unconfined)
* @cap: capability to test if allowed
*
* Returns: 0 if allowed else -EPERM
*/
static int profile_capable(struct aa_profile *profile, int cap)
{
return cap_raised(profile->caps.allow, cap) ? 0 : -EPERM;
}
/**
* aa_capable - test permission to use capability
* @profile: profile being tested against (NOT NULL)
* @cap: capability to be tested
* @audit: whether an audit record should be generated
*
* Look up capability in profile capability set.
*
* Returns: 0 on success, or else an error code.
*/
int aa_capable(struct aa_profile *profile, int cap, int audit)
{
int error = profile_capable(profile, cap);
if (!audit) {
if (COMPLAIN_MODE(profile))
return complain_error(error);
return error;
}
return audit_caps(profile, cap, error);
}