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// SPDX-License-Identifier: GPL-2.0-only
/*
* AppArmor security module
*
* This file contains AppArmor capability mediation functions
*
* Copyright (C) 1998-2008 Novell/SUSE
* Copyright 2009-2010 Canonical Ltd.
*/
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/gfp.h>
#include <linux/security.h>
#include "include/apparmor.h"
#include "include/capability.h"
#include "include/cred.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_sfs_entry aa_sfs_entry_caps[] = {
AA_SFS_FILE_STRING("mask", AA_SFS_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
* @ad: audit data
* @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 ad->error on success, error code on failure
*/
static int audit_caps(struct apparmor_audit_data *ad, struct aa_profile *profile,
int cap, int error)
{
struct aa_ruleset *rules = list_first_entry(&profile->rules,
typeof(*rules), list);
struct audit_cache *ent;
int type = AUDIT_APPARMOR_AUTO;
ad->error = error;
if (likely(!error)) {
/* test if auditing is being forced */
if (likely((AUDIT_MODE(profile) != AUDIT_ALL) &&
!cap_raised(rules->caps.audit, cap)))
return 0;
type = AUDIT_APPARMOR_AUDIT;
} else if (KILL_MODE(profile) ||
cap_raised(rules->caps.kill, cap)) {
type = AUDIT_APPARMOR_KILL;
} else if (cap_raised(rules->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);
if (profile != ent->profile)
cap_clear(ent->caps);
ent->profile = aa_get_profile(profile);
cap_raise(ent->caps, cap);
}
put_cpu_var(audit_cache);
return aa_audit(type, profile, ad, 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
* @opts: CAP_OPT_NOAUDIT bit determines whether audit record is generated
* @ad: audit data (NOT NULL)
*
* Returns: 0 if allowed else -EPERM
*/
static int profile_capable(struct aa_profile *profile, int cap,
unsigned int opts, struct apparmor_audit_data *ad)
{
struct aa_ruleset *rules = list_first_entry(&profile->rules,
typeof(*rules), list);
int error;
if (cap_raised(rules->caps.allow, cap) &&
!cap_raised(rules->caps.denied, cap))
error = 0;
else
error = -EPERM;
if (opts & CAP_OPT_NOAUDIT) {
if (!COMPLAIN_MODE(profile))
return error;
/* audit the cap request in complain mode but note that it
* should be optional.
*/
ad->info = "optional: no audit";
}
return audit_caps(ad, profile, cap, error);
}
/**
* aa_capable - test permission to use capability
* @subj_cred: cred we are testing capability against
* @label: label being tested for capability (NOT NULL)
* @cap: capability to be tested
* @opts: CAP_OPT_NOAUDIT bit determines whether audit record is generated
*
* Look up capability in profile capability set.
*
* Returns: 0 on success, or else an error code.
*/
int aa_capable(const struct cred *subj_cred, struct aa_label *label,
int cap, unsigned int opts)
{
struct aa_profile *profile;
int error = 0;
DEFINE_AUDIT_DATA(ad, LSM_AUDIT_DATA_CAP, AA_CLASS_CAP, OP_CAPABLE);
ad.subj_cred = subj_cred;
ad.common.u.cap = cap;
error = fn_for_each_confined(label, profile,
profile_capable(profile, cap, opts, &ad));
return error;
}
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