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