1/* audit.c -- Auditing support
   2 * Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
   3 * System-call specific features have moved to auditsc.c
   4 *
   5 * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
   6 * All Rights Reserved.
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License as published by
  10 * the Free Software Foundation; either version 2 of the License, or
  11 * (at your option) any later version.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21 *
  22 * Written by Rickard E. (Rik) Faith <faith@redhat.com>
  23 *
  24 * Goals: 1) Integrate fully with Security Modules.
  25 *	  2) Minimal run-time overhead:
  26 *	     a) Minimal when syscall auditing is disabled (audit_enable=0).
  27 *	     b) Small when syscall auditing is enabled and no audit record
  28 *		is generated (defer as much work as possible to record
  29 *		generation time):
  30 *		i) context is allocated,
  31 *		ii) names from getname are stored without a copy, and
  32 *		iii) inode information stored from path_lookup.
  33 *	  3) Ability to disable syscall auditing at boot time (audit=0).
  34 *	  4) Usable by other parts of the kernel (if audit_log* is called,
  35 *	     then a syscall record will be generated automatically for the
  36 *	     current syscall).
  37 *	  5) Netlink interface to user-space.
  38 *	  6) Support low-overhead kernel-based filtering to minimize the
  39 *	     information that must be passed to user-space.
  40 *
  41 * Audit userspace, documentation, tests, and bug/issue trackers:
  42 * 	https://github.com/linux-audit
  43 */
  44
  45#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  46
  47#include <linux/file.h>
  48#include <linux/init.h>
  49#include <linux/types.h>
  50#include <linux/atomic.h>
  51#include <linux/mm.h>
  52#include <linux/export.h>
  53#include <linux/slab.h>
  54#include <linux/err.h>
  55#include <linux/kthread.h>
  56#include <linux/kernel.h>
  57#include <linux/syscalls.h>
  58#include <linux/spinlock.h>
  59#include <linux/rcupdate.h>
  60#include <linux/mutex.h>
  61#include <linux/gfp.h>
  62#include <linux/pid.h>
  63#include <linux/slab.h>
  64
  65#include <linux/audit.h>
  66
  67#include <net/sock.h>
  68#include <net/netlink.h>
  69#include <linux/skbuff.h>
  70#ifdef CONFIG_SECURITY
  71#include <linux/security.h>
  72#endif
  73#include <linux/freezer.h>
 
  74#include <linux/pid_namespace.h>
  75#include <net/netns/generic.h>
  76
  77#include "audit.h"
  78
  79/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
  80 * (Initialization happens after skb_init is called.) */
  81#define AUDIT_DISABLED		-1
  82#define AUDIT_UNINITIALIZED	0
  83#define AUDIT_INITIALIZED	1
  84static int	audit_initialized;
  85
  86#define AUDIT_OFF	0
  87#define AUDIT_ON	1
  88#define AUDIT_LOCKED	2
  89u32		audit_enabled = AUDIT_OFF;
  90bool		audit_ever_enabled = !!AUDIT_OFF;
  91
  92EXPORT_SYMBOL_GPL(audit_enabled);
  93
  94/* Default state when kernel boots without any parameters. */
  95static u32	audit_default = AUDIT_OFF;
  96
  97/* If auditing cannot proceed, audit_failure selects what happens. */
  98static u32	audit_failure = AUDIT_FAIL_PRINTK;
  99
 100/* private audit network namespace index */
 101static unsigned int audit_net_id;
 102
 103/**
 104 * struct audit_net - audit private network namespace data
 105 * @sk: communication socket
 106 */
 107struct audit_net {
 108	struct sock *sk;
 109};
 110
 111/**
 112 * struct auditd_connection - kernel/auditd connection state
 113 * @pid: auditd PID
 114 * @portid: netlink portid
 115 * @net: the associated network namespace
 116 * @rcu: RCU head
 117 *
 118 * Description:
 119 * This struct is RCU protected; you must either hold the RCU lock for reading
 120 * or the associated spinlock for writing.
 121 */
 122static struct auditd_connection {
 123	struct pid *pid;
 124	u32 portid;
 125	struct net *net;
 126	struct rcu_head rcu;
 127} *auditd_conn = NULL;
 128static DEFINE_SPINLOCK(auditd_conn_lock);
 129
 130/* If audit_rate_limit is non-zero, limit the rate of sending audit records
 131 * to that number per second.  This prevents DoS attacks, but results in
 132 * audit records being dropped. */
 133static u32	audit_rate_limit;
 134
 135/* Number of outstanding audit_buffers allowed.
 136 * When set to zero, this means unlimited. */
 137static u32	audit_backlog_limit = 64;
 138#define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
 
 139static u32	audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
 140
 141/* The identity of the user shutting down the audit system. */
 142kuid_t		audit_sig_uid = INVALID_UID;
 143pid_t		audit_sig_pid = -1;
 144u32		audit_sig_sid = 0;
 145
 146/* Records can be lost in several ways:
 147   0) [suppressed in audit_alloc]
 148   1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
 149   2) out of memory in audit_log_move [alloc_skb]
 150   3) suppressed due to audit_rate_limit
 151   4) suppressed due to audit_backlog_limit
 152*/
 153static atomic_t	audit_lost = ATOMIC_INIT(0);
 
 
 
 
 154
 155/* Hash for inode-based rules */
 156struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
 157
 158static struct kmem_cache *audit_buffer_cache;
 159
 160/* queue msgs to send via kauditd_task */
 161static struct sk_buff_head audit_queue;
 162/* queue msgs due to temporary unicast send problems */
 163static struct sk_buff_head audit_retry_queue;
 164/* queue msgs waiting for new auditd connection */
 165static struct sk_buff_head audit_hold_queue;
 166
 167/* queue servicing thread */
 168static struct task_struct *kauditd_task;
 169static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
 170
 171/* waitqueue for callers who are blocked on the audit backlog */
 172static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
 173
 174static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
 175				   .mask = -1,
 176				   .features = 0,
 177				   .lock = 0,};
 178
 179static char *audit_feature_names[2] = {
 180	"only_unset_loginuid",
 181	"loginuid_immutable",
 182};
 183
 184/**
 185 * struct audit_ctl_mutex - serialize requests from userspace
 186 * @lock: the mutex used for locking
 187 * @owner: the task which owns the lock
 188 *
 189 * Description:
 190 * This is the lock struct used to ensure we only process userspace requests
 191 * in an orderly fashion.  We can't simply use a mutex/lock here because we
 192 * need to track lock ownership so we don't end up blocking the lock owner in
 193 * audit_log_start() or similar.
 194 */
 195static struct audit_ctl_mutex {
 196	struct mutex lock;
 197	void *owner;
 198} audit_cmd_mutex;
 199
 200/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
 201 * audit records.  Since printk uses a 1024 byte buffer, this buffer
 202 * should be at least that large. */
 203#define AUDIT_BUFSIZ 1024
 204
 
 
 
 
 205/* The audit_buffer is used when formatting an audit record.  The caller
 206 * locks briefly to get the record off the freelist or to allocate the
 207 * buffer, and locks briefly to send the buffer to the netlink layer or
 208 * to place it on a transmit queue.  Multiple audit_buffers can be in
 209 * use simultaneously. */
 210struct audit_buffer {
 
 211	struct sk_buff       *skb;	/* formatted skb ready to send */
 212	struct audit_context *ctx;	/* NULL or associated context */
 213	gfp_t		     gfp_mask;
 214};
 215
 216struct audit_reply {
 217	__u32 portid;
 218	struct net *net;
 219	struct sk_buff *skb;
 220};
 221
 222/**
 223 * auditd_test_task - Check to see if a given task is an audit daemon
 224 * @task: the task to check
 225 *
 226 * Description:
 227 * Return 1 if the task is a registered audit daemon, 0 otherwise.
 228 */
 229int auditd_test_task(struct task_struct *task)
 230{
 231	int rc;
 232	struct auditd_connection *ac;
 233
 234	rcu_read_lock();
 235	ac = rcu_dereference(auditd_conn);
 236	rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
 237	rcu_read_unlock();
 238
 239	return rc;
 240}
 241
 242/**
 243 * audit_ctl_lock - Take the audit control lock
 244 */
 245void audit_ctl_lock(void)
 246{
 247	mutex_lock(&audit_cmd_mutex.lock);
 248	audit_cmd_mutex.owner = current;
 249}
 250
 251/**
 252 * audit_ctl_unlock - Drop the audit control lock
 253 */
 254void audit_ctl_unlock(void)
 255{
 256	audit_cmd_mutex.owner = NULL;
 257	mutex_unlock(&audit_cmd_mutex.lock);
 258}
 259
 260/**
 261 * audit_ctl_owner_current - Test to see if the current task owns the lock
 262 *
 263 * Description:
 264 * Return true if the current task owns the audit control lock, false if it
 265 * doesn't own the lock.
 266 */
 267static bool audit_ctl_owner_current(void)
 268{
 269	return (current == audit_cmd_mutex.owner);
 270}
 271
 272/**
 273 * auditd_pid_vnr - Return the auditd PID relative to the namespace
 274 *
 275 * Description:
 276 * Returns the PID in relation to the namespace, 0 on failure.
 277 */
 278static pid_t auditd_pid_vnr(void)
 279{
 280	pid_t pid;
 281	const struct auditd_connection *ac;
 282
 283	rcu_read_lock();
 284	ac = rcu_dereference(auditd_conn);
 285	if (!ac || !ac->pid)
 286		pid = 0;
 287	else
 288		pid = pid_vnr(ac->pid);
 289	rcu_read_unlock();
 290
 291	return pid;
 292}
 293
 294/**
 295 * audit_get_sk - Return the audit socket for the given network namespace
 296 * @net: the destination network namespace
 297 *
 298 * Description:
 299 * Returns the sock pointer if valid, NULL otherwise.  The caller must ensure
 300 * that a reference is held for the network namespace while the sock is in use.
 301 */
 302static struct sock *audit_get_sk(const struct net *net)
 303{
 304	struct audit_net *aunet;
 305
 306	if (!net)
 307		return NULL;
 308
 309	aunet = net_generic(net, audit_net_id);
 310	return aunet->sk;
 311}
 312
 313void audit_panic(const char *message)
 314{
 315	switch (audit_failure) {
 316	case AUDIT_FAIL_SILENT:
 317		break;
 318	case AUDIT_FAIL_PRINTK:
 319		if (printk_ratelimit())
 320			pr_err("%s\n", message);
 321		break;
 322	case AUDIT_FAIL_PANIC:
 323		panic("audit: %s\n", message);
 
 
 324		break;
 325	}
 326}
 327
 328static inline int audit_rate_check(void)
 329{
 330	static unsigned long	last_check = 0;
 331	static int		messages   = 0;
 332	static DEFINE_SPINLOCK(lock);
 333	unsigned long		flags;
 334	unsigned long		now;
 335	unsigned long		elapsed;
 336	int			retval	   = 0;
 337
 338	if (!audit_rate_limit) return 1;
 339
 340	spin_lock_irqsave(&lock, flags);
 341	if (++messages < audit_rate_limit) {
 342		retval = 1;
 343	} else {
 344		now     = jiffies;
 345		elapsed = now - last_check;
 346		if (elapsed > HZ) {
 347			last_check = now;
 348			messages   = 0;
 349			retval     = 1;
 350		}
 351	}
 352	spin_unlock_irqrestore(&lock, flags);
 353
 354	return retval;
 355}
 356
 357/**
 358 * audit_log_lost - conditionally log lost audit message event
 359 * @message: the message stating reason for lost audit message
 360 *
 361 * Emit at least 1 message per second, even if audit_rate_check is
 362 * throttling.
 363 * Always increment the lost messages counter.
 364*/
 365void audit_log_lost(const char *message)
 366{
 367	static unsigned long	last_msg = 0;
 368	static DEFINE_SPINLOCK(lock);
 369	unsigned long		flags;
 370	unsigned long		now;
 371	int			print;
 372
 373	atomic_inc(&audit_lost);
 374
 375	print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
 376
 377	if (!print) {
 378		spin_lock_irqsave(&lock, flags);
 379		now = jiffies;
 380		if (now - last_msg > HZ) {
 381			print = 1;
 382			last_msg = now;
 383		}
 384		spin_unlock_irqrestore(&lock, flags);
 385	}
 386
 387	if (print) {
 388		if (printk_ratelimit())
 389			pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
 390				atomic_read(&audit_lost),
 391				audit_rate_limit,
 392				audit_backlog_limit);
 393		audit_panic(message);
 394	}
 395}
 396
 397static int audit_log_config_change(char *function_name, u32 new, u32 old,
 398				   int allow_changes)
 399{
 400	struct audit_buffer *ab;
 401	int rc = 0;
 402
 403	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
 404	if (unlikely(!ab))
 405		return rc;
 406	audit_log_format(ab, "%s=%u old=%u", function_name, new, old);
 407	audit_log_session_info(ab);
 408	rc = audit_log_task_context(ab);
 409	if (rc)
 410		allow_changes = 0; /* Something weird, deny request */
 411	audit_log_format(ab, " res=%d", allow_changes);
 412	audit_log_end(ab);
 413	return rc;
 414}
 415
 416static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
 417{
 418	int allow_changes, rc = 0;
 419	u32 old = *to_change;
 420
 421	/* check if we are locked */
 422	if (audit_enabled == AUDIT_LOCKED)
 423		allow_changes = 0;
 424	else
 425		allow_changes = 1;
 426
 427	if (audit_enabled != AUDIT_OFF) {
 428		rc = audit_log_config_change(function_name, new, old, allow_changes);
 429		if (rc)
 430			allow_changes = 0;
 431	}
 432
 433	/* If we are allowed, make the change */
 434	if (allow_changes == 1)
 435		*to_change = new;
 436	/* Not allowed, update reason */
 437	else if (rc == 0)
 438		rc = -EPERM;
 439	return rc;
 440}
 441
 442static int audit_set_rate_limit(u32 limit)
 443{
 444	return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
 445}
 446
 447static int audit_set_backlog_limit(u32 limit)
 448{
 449	return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
 450}
 451
 452static int audit_set_backlog_wait_time(u32 timeout)
 453{
 454	return audit_do_config_change("audit_backlog_wait_time",
 455				      &audit_backlog_wait_time, timeout);
 456}
 457
 458static int audit_set_enabled(u32 state)
 459{
 460	int rc;
 461	if (state > AUDIT_LOCKED)
 462		return -EINVAL;
 463
 464	rc =  audit_do_config_change("audit_enabled", &audit_enabled, state);
 465	if (!rc)
 466		audit_ever_enabled |= !!state;
 467
 468	return rc;
 469}
 470
 471static int audit_set_failure(u32 state)
 472{
 473	if (state != AUDIT_FAIL_SILENT
 474	    && state != AUDIT_FAIL_PRINTK
 475	    && state != AUDIT_FAIL_PANIC)
 476		return -EINVAL;
 477
 478	return audit_do_config_change("audit_failure", &audit_failure, state);
 479}
 480
 481/**
 482 * auditd_conn_free - RCU helper to release an auditd connection struct
 483 * @rcu: RCU head
 484 *
 485 * Description:
 486 * Drop any references inside the auditd connection tracking struct and free
 487 * the memory.
 488 */
 489static void auditd_conn_free(struct rcu_head *rcu)
 490{
 491	struct auditd_connection *ac;
 492
 493	ac = container_of(rcu, struct auditd_connection, rcu);
 494	put_pid(ac->pid);
 495	put_net(ac->net);
 496	kfree(ac);
 497}
 498
 499/**
 500 * auditd_set - Set/Reset the auditd connection state
 501 * @pid: auditd PID
 502 * @portid: auditd netlink portid
 503 * @net: auditd network namespace pointer
 504 *
 505 * Description:
 506 * This function will obtain and drop network namespace references as
 507 * necessary.  Returns zero on success, negative values on failure.
 508 */
 509static int auditd_set(struct pid *pid, u32 portid, struct net *net)
 510{
 511	unsigned long flags;
 512	struct auditd_connection *ac_old, *ac_new;
 513
 514	if (!pid || !net)
 515		return -EINVAL;
 516
 517	ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL);
 518	if (!ac_new)
 519		return -ENOMEM;
 520	ac_new->pid = get_pid(pid);
 521	ac_new->portid = portid;
 522	ac_new->net = get_net(net);
 523
 524	spin_lock_irqsave(&auditd_conn_lock, flags);
 525	ac_old = rcu_dereference_protected(auditd_conn,
 526					   lockdep_is_held(&auditd_conn_lock));
 527	rcu_assign_pointer(auditd_conn, ac_new);
 528	spin_unlock_irqrestore(&auditd_conn_lock, flags);
 529
 530	if (ac_old)
 531		call_rcu(&ac_old->rcu, auditd_conn_free);
 532
 533	return 0;
 534}
 535
 536/**
 537 * kauditd_print_skb - Print the audit record to the ring buffer
 538 * @skb: audit record
 539 *
 540 * Whatever the reason, this packet may not make it to the auditd connection
 541 * so write it via printk so the information isn't completely lost.
 542 */
 543static void kauditd_printk_skb(struct sk_buff *skb)
 544{
 545	struct nlmsghdr *nlh = nlmsg_hdr(skb);
 546	char *data = nlmsg_data(nlh);
 547
 548	if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
 549		pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
 550}
 551
 552/**
 553 * kauditd_rehold_skb - Handle a audit record send failure in the hold queue
 554 * @skb: audit record
 555 *
 556 * Description:
 557 * This should only be used by the kauditd_thread when it fails to flush the
 558 * hold queue.
 559 */
 560static void kauditd_rehold_skb(struct sk_buff *skb)
 561{
 562	/* put the record back in the queue at the same place */
 563	skb_queue_head(&audit_hold_queue, skb);
 564}
 565
 566/**
 567 * kauditd_hold_skb - Queue an audit record, waiting for auditd
 568 * @skb: audit record
 569 *
 570 * Description:
 571 * Queue the audit record, waiting for an instance of auditd.  When this
 572 * function is called we haven't given up yet on sending the record, but things
 573 * are not looking good.  The first thing we want to do is try to write the
 574 * record via printk and then see if we want to try and hold on to the record
 575 * and queue it, if we have room.  If we want to hold on to the record, but we
 576 * don't have room, record a record lost message.
 577 */
 578static void kauditd_hold_skb(struct sk_buff *skb)
 579{
 580	/* at this point it is uncertain if we will ever send this to auditd so
 581	 * try to send the message via printk before we go any further */
 582	kauditd_printk_skb(skb);
 583
 584	/* can we just silently drop the message? */
 585	if (!audit_default) {
 586		kfree_skb(skb);
 587		return;
 588	}
 589
 590	/* if we have room, queue the message */
 591	if (!audit_backlog_limit ||
 592	    skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
 593		skb_queue_tail(&audit_hold_queue, skb);
 594		return;
 595	}
 596
 597	/* we have no other options - drop the message */
 598	audit_log_lost("kauditd hold queue overflow");
 599	kfree_skb(skb);
 600}
 601
 602/**
 603 * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
 604 * @skb: audit record
 605 *
 606 * Description:
 607 * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
 608 * but for some reason we are having problems sending it audit records so
 609 * queue the given record and attempt to resend.
 610 */
 611static void kauditd_retry_skb(struct sk_buff *skb)
 612{
 613	/* NOTE: because records should only live in the retry queue for a
 614	 * short period of time, before either being sent or moved to the hold
 615	 * queue, we don't currently enforce a limit on this queue */
 616	skb_queue_tail(&audit_retry_queue, skb);
 617}
 618
 619/**
 620 * auditd_reset - Disconnect the auditd connection
 621 * @ac: auditd connection state
 622 *
 623 * Description:
 624 * Break the auditd/kauditd connection and move all the queued records into the
 625 * hold queue in case auditd reconnects.  It is important to note that the @ac
 626 * pointer should never be dereferenced inside this function as it may be NULL
 627 * or invalid, you can only compare the memory address!  If @ac is NULL then
 628 * the connection will always be reset.
 629 */
 630static void auditd_reset(const struct auditd_connection *ac)
 631{
 632	unsigned long flags;
 633	struct sk_buff *skb;
 634	struct auditd_connection *ac_old;
 635
 636	/* if it isn't already broken, break the connection */
 637	spin_lock_irqsave(&auditd_conn_lock, flags);
 638	ac_old = rcu_dereference_protected(auditd_conn,
 639					   lockdep_is_held(&auditd_conn_lock));
 640	if (ac && ac != ac_old) {
 641		/* someone already registered a new auditd connection */
 642		spin_unlock_irqrestore(&auditd_conn_lock, flags);
 643		return;
 644	}
 645	rcu_assign_pointer(auditd_conn, NULL);
 646	spin_unlock_irqrestore(&auditd_conn_lock, flags);
 647
 648	if (ac_old)
 649		call_rcu(&ac_old->rcu, auditd_conn_free);
 650
 651	/* flush the retry queue to the hold queue, but don't touch the main
 652	 * queue since we need to process that normally for multicast */
 653	while ((skb = skb_dequeue(&audit_retry_queue)))
 654		kauditd_hold_skb(skb);
 655}
 656
 657/**
 658 * auditd_send_unicast_skb - Send a record via unicast to auditd
 659 * @skb: audit record
 660 *
 661 * Description:
 662 * Send a skb to the audit daemon, returns positive/zero values on success and
 663 * negative values on failure; in all cases the skb will be consumed by this
 664 * function.  If the send results in -ECONNREFUSED the connection with auditd
 665 * will be reset.  This function may sleep so callers should not hold any locks
 666 * where this would cause a problem.
 667 */
 668static int auditd_send_unicast_skb(struct sk_buff *skb)
 669{
 670	int rc;
 671	u32 portid;
 672	struct net *net;
 673	struct sock *sk;
 674	struct auditd_connection *ac;
 675
 676	/* NOTE: we can't call netlink_unicast while in the RCU section so
 677	 *       take a reference to the network namespace and grab local
 678	 *       copies of the namespace, the sock, and the portid; the
 679	 *       namespace and sock aren't going to go away while we hold a
 680	 *       reference and if the portid does become invalid after the RCU
 681	 *       section netlink_unicast() should safely return an error */
 682
 683	rcu_read_lock();
 684	ac = rcu_dereference(auditd_conn);
 685	if (!ac) {
 686		rcu_read_unlock();
 687		kfree_skb(skb);
 688		rc = -ECONNREFUSED;
 689		goto err;
 690	}
 691	net = get_net(ac->net);
 692	sk = audit_get_sk(net);
 693	portid = ac->portid;
 694	rcu_read_unlock();
 695
 696	rc = netlink_unicast(sk, skb, portid, 0);
 697	put_net(net);
 698	if (rc < 0)
 699		goto err;
 700
 701	return rc;
 702
 703err:
 704	if (ac && rc == -ECONNREFUSED)
 705		auditd_reset(ac);
 706	return rc;
 707}
 708
 709/**
 710 * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
 711 * @sk: the sending sock
 712 * @portid: the netlink destination
 713 * @queue: the skb queue to process
 714 * @retry_limit: limit on number of netlink unicast failures
 715 * @skb_hook: per-skb hook for additional processing
 716 * @err_hook: hook called if the skb fails the netlink unicast send
 717 *
 718 * Description:
 719 * Run through the given queue and attempt to send the audit records to auditd,
 720 * returns zero on success, negative values on failure.  It is up to the caller
 721 * to ensure that the @sk is valid for the duration of this function.
 722 *
 723 */
 724static int kauditd_send_queue(struct sock *sk, u32 portid,
 725			      struct sk_buff_head *queue,
 726			      unsigned int retry_limit,
 727			      void (*skb_hook)(struct sk_buff *skb),
 728			      void (*err_hook)(struct sk_buff *skb))
 729{
 730	int rc = 0;
 731	struct sk_buff *skb;
 732	static unsigned int failed = 0;
 733
 734	/* NOTE: kauditd_thread takes care of all our locking, we just use
 735	 *       the netlink info passed to us (e.g. sk and portid) */
 736
 737	while ((skb = skb_dequeue(queue))) {
 738		/* call the skb_hook for each skb we touch */
 739		if (skb_hook)
 740			(*skb_hook)(skb);
 741
 742		/* can we send to anyone via unicast? */
 743		if (!sk) {
 744			if (err_hook)
 745				(*err_hook)(skb);
 746			continue;
 747		}
 748
 749		/* grab an extra skb reference in case of error */
 750		skb_get(skb);
 751		rc = netlink_unicast(sk, skb, portid, 0);
 752		if (rc < 0) {
 753			/* fatal failure for our queue flush attempt? */
 754			if (++failed >= retry_limit ||
 755			    rc == -ECONNREFUSED || rc == -EPERM) {
 756				/* yes - error processing for the queue */
 757				sk = NULL;
 758				if (err_hook)
 759					(*err_hook)(skb);
 760				if (!skb_hook)
 761					goto out;
 762				/* keep processing with the skb_hook */
 763				continue;
 764			} else
 765				/* no - requeue to preserve ordering */
 766				skb_queue_head(queue, skb);
 767		} else {
 768			/* it worked - drop the extra reference and continue */
 769			consume_skb(skb);
 770			failed = 0;
 
 
 771		}
 772	}
 773
 774out:
 775	return (rc >= 0 ? 0 : rc);
 
 776}
 777
 778/*
 779 * kauditd_send_multicast_skb - Send a record to any multicast listeners
 780 * @skb: audit record
 781 *
 782 * Description:
 783 * Write a multicast message to anyone listening in the initial network
 784 * namespace.  This function doesn't consume an skb as might be expected since
 785 * it has to copy it anyways.
 786 */
 787static void kauditd_send_multicast_skb(struct sk_buff *skb)
 788{
 789	struct sk_buff *copy;
 790	struct sock *sock = audit_get_sk(&init_net);
 791	struct nlmsghdr *nlh;
 792
 793	/* NOTE: we are not taking an additional reference for init_net since
 794	 *       we don't have to worry about it going away */
 795
 796	if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
 797		return;
 798
 799	/*
 800	 * The seemingly wasteful skb_copy() rather than bumping the refcount
 801	 * using skb_get() is necessary because non-standard mods are made to
 802	 * the skb by the original kaudit unicast socket send routine.  The
 803	 * existing auditd daemon assumes this breakage.  Fixing this would
 804	 * require co-ordinating a change in the established protocol between
 805	 * the kaudit kernel subsystem and the auditd userspace code.  There is
 806	 * no reason for new multicast clients to continue with this
 807	 * non-compliance.
 808	 */
 809	copy = skb_copy(skb, GFP_KERNEL);
 810	if (!copy)
 811		return;
 812	nlh = nlmsg_hdr(copy);
 813	nlh->nlmsg_len = skb->len;
 814
 815	nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
 816}
 817
 818/**
 819 * kauditd_thread - Worker thread to send audit records to userspace
 820 * @dummy: unused
 
 
 
 
 
 
 
 
 
 
 
 821 */
 822static int kauditd_thread(void *dummy)
 823{
 824	int rc;
 825	u32 portid = 0;
 826	struct net *net = NULL;
 827	struct sock *sk = NULL;
 828	struct auditd_connection *ac;
 829
 830#define UNICAST_RETRIES 5
 
 
 
 
 
 
 
 
 
 
 831
 
 
 
 
 
 
 
 
 
 832	set_freezable();
 833	while (!kthread_should_stop()) {
 834		/* NOTE: see the lock comments in auditd_send_unicast_skb() */
 835		rcu_read_lock();
 836		ac = rcu_dereference(auditd_conn);
 837		if (!ac) {
 838			rcu_read_unlock();
 839			goto main_queue;
 840		}
 841		net = get_net(ac->net);
 842		sk = audit_get_sk(net);
 843		portid = ac->portid;
 844		rcu_read_unlock();
 845
 846		/* attempt to flush the hold queue */
 847		rc = kauditd_send_queue(sk, portid,
 848					&audit_hold_queue, UNICAST_RETRIES,
 849					NULL, kauditd_rehold_skb);
 850		if (ac && rc < 0) {
 851			sk = NULL;
 852			auditd_reset(ac);
 853			goto main_queue;
 854		}
 855
 856		/* attempt to flush the retry queue */
 857		rc = kauditd_send_queue(sk, portid,
 858					&audit_retry_queue, UNICAST_RETRIES,
 859					NULL, kauditd_hold_skb);
 860		if (ac && rc < 0) {
 861			sk = NULL;
 862			auditd_reset(ac);
 863			goto main_queue;
 864		}
 865
 866main_queue:
 867		/* process the main queue - do the multicast send and attempt
 868		 * unicast, dump failed record sends to the retry queue; if
 869		 * sk == NULL due to previous failures we will just do the
 870		 * multicast send and move the record to the hold queue */
 871		rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
 872					kauditd_send_multicast_skb,
 873					(sk ?
 874					 kauditd_retry_skb : kauditd_hold_skb));
 875		if (ac && rc < 0)
 876			auditd_reset(ac);
 877		sk = NULL;
 878
 879		/* drop our netns reference, no auditd sends past this line */
 880		if (net) {
 881			put_net(net);
 882			net = NULL;
 883		}
 884
 885		/* we have processed all the queues so wake everyone */
 886		wake_up(&audit_backlog_wait);
 887
 888		/* NOTE: we want to wake up if there is anything on the queue,
 889		 *       regardless of if an auditd is connected, as we need to
 890		 *       do the multicast send and rotate records from the
 891		 *       main queue to the retry/hold queues */
 892		wait_event_freezable(kauditd_wait,
 893				     (skb_queue_len(&audit_queue) ? 1 : 0));
 894	}
 
 
 
 
 
 895
 
 
 896	return 0;
 897}
 898
 899int audit_send_list(void *_dest)
 900{
 901	struct audit_netlink_list *dest = _dest;
 902	struct sk_buff *skb;
 903	struct sock *sk = audit_get_sk(dest->net);
 
 904
 905	/* wait for parent to finish and send an ACK */
 906	audit_ctl_lock();
 907	audit_ctl_unlock();
 908
 909	while ((skb = __skb_dequeue(&dest->q)) != NULL)
 910		netlink_unicast(sk, skb, dest->portid, 0);
 911
 912	put_net(dest->net);
 913	kfree(dest);
 914
 915	return 0;
 916}
 917
 918struct sk_buff *audit_make_reply(int seq, int type, int done,
 919				 int multi, const void *payload, int size)
 920{
 921	struct sk_buff	*skb;
 922	struct nlmsghdr	*nlh;
 923	void		*data;
 924	int		flags = multi ? NLM_F_MULTI : 0;
 925	int		t     = done  ? NLMSG_DONE  : type;
 926
 927	skb = nlmsg_new(size, GFP_KERNEL);
 928	if (!skb)
 929		return NULL;
 930
 931	nlh	= nlmsg_put(skb, 0, seq, t, size, flags);
 932	if (!nlh)
 933		goto out_kfree_skb;
 934	data = nlmsg_data(nlh);
 935	memcpy(data, payload, size);
 936	return skb;
 937
 938out_kfree_skb:
 939	kfree_skb(skb);
 940	return NULL;
 941}
 942
 943static int audit_send_reply_thread(void *arg)
 944{
 945	struct audit_reply *reply = (struct audit_reply *)arg;
 946	struct sock *sk = audit_get_sk(reply->net);
 
 947
 948	audit_ctl_lock();
 949	audit_ctl_unlock();
 950
 951	/* Ignore failure. It'll only happen if the sender goes away,
 952	   because our timeout is set to infinite. */
 953	netlink_unicast(sk, reply->skb, reply->portid, 0);
 954	put_net(reply->net);
 955	kfree(reply);
 956	return 0;
 957}
 958
 959/**
 960 * audit_send_reply - send an audit reply message via netlink
 961 * @request_skb: skb of request we are replying to (used to target the reply)
 962 * @seq: sequence number
 963 * @type: audit message type
 964 * @done: done (last) flag
 965 * @multi: multi-part message flag
 966 * @payload: payload data
 967 * @size: payload size
 968 *
 969 * Allocates an skb, builds the netlink message, and sends it to the port id.
 970 * No failure notifications.
 971 */
 972static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
 973			     int multi, const void *payload, int size)
 974{
 
 975	struct net *net = sock_net(NETLINK_CB(request_skb).sk);
 976	struct sk_buff *skb;
 977	struct task_struct *tsk;
 978	struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
 979					    GFP_KERNEL);
 980
 981	if (!reply)
 982		return;
 983
 984	skb = audit_make_reply(seq, type, done, multi, payload, size);
 985	if (!skb)
 986		goto out;
 987
 988	reply->net = get_net(net);
 989	reply->portid = NETLINK_CB(request_skb).portid;
 990	reply->skb = skb;
 991
 992	tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
 993	if (!IS_ERR(tsk))
 994		return;
 995	kfree_skb(skb);
 996out:
 997	kfree(reply);
 998}
 999
1000/*
1001 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
1002 * control messages.
1003 */
1004static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
1005{
1006	int err = 0;
1007
1008	/* Only support initial user namespace for now. */
1009	/*
1010	 * We return ECONNREFUSED because it tricks userspace into thinking
1011	 * that audit was not configured into the kernel.  Lots of users
1012	 * configure their PAM stack (because that's what the distro does)
1013	 * to reject login if unable to send messages to audit.  If we return
1014	 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
1015	 * configured in and will let login proceed.  If we return EPERM
1016	 * userspace will reject all logins.  This should be removed when we
1017	 * support non init namespaces!!
1018	 */
1019	if (current_user_ns() != &init_user_ns)
1020		return -ECONNREFUSED;
1021
1022	switch (msg_type) {
1023	case AUDIT_LIST:
1024	case AUDIT_ADD:
1025	case AUDIT_DEL:
1026		return -EOPNOTSUPP;
1027	case AUDIT_GET:
1028	case AUDIT_SET:
1029	case AUDIT_GET_FEATURE:
1030	case AUDIT_SET_FEATURE:
1031	case AUDIT_LIST_RULES:
1032	case AUDIT_ADD_RULE:
1033	case AUDIT_DEL_RULE:
1034	case AUDIT_SIGNAL_INFO:
1035	case AUDIT_TTY_GET:
1036	case AUDIT_TTY_SET:
1037	case AUDIT_TRIM:
1038	case AUDIT_MAKE_EQUIV:
1039		/* Only support auditd and auditctl in initial pid namespace
1040		 * for now. */
1041		if (task_active_pid_ns(current) != &init_pid_ns)
1042			return -EPERM;
1043
1044		if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
1045			err = -EPERM;
1046		break;
1047	case AUDIT_USER:
1048	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1049	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1050		if (!netlink_capable(skb, CAP_AUDIT_WRITE))
1051			err = -EPERM;
1052		break;
1053	default:  /* bad msg */
1054		err = -EINVAL;
1055	}
1056
1057	return err;
1058}
1059
1060static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
1061{
1062	uid_t uid = from_kuid(&init_user_ns, current_uid());
1063	pid_t pid = task_tgid_nr(current);
1064
1065	if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
1066		*ab = NULL;
1067		return;
1068	}
1069
1070	*ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
1071	if (unlikely(!*ab))
1072		return;
1073	audit_log_format(*ab, "pid=%d uid=%u", pid, uid);
1074	audit_log_session_info(*ab);
1075	audit_log_task_context(*ab);
1076}
1077
1078int is_audit_feature_set(int i)
1079{
1080	return af.features & AUDIT_FEATURE_TO_MASK(i);
1081}
1082
1083
1084static int audit_get_feature(struct sk_buff *skb)
1085{
1086	u32 seq;
1087
1088	seq = nlmsg_hdr(skb)->nlmsg_seq;
1089
1090	audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
1091
1092	return 0;
1093}
1094
1095static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
1096				     u32 old_lock, u32 new_lock, int res)
1097{
1098	struct audit_buffer *ab;
1099
1100	if (audit_enabled == AUDIT_OFF)
1101		return;
1102
1103	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE);
1104	if (!ab)
1105		return;
1106	audit_log_task_info(ab, current);
1107	audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
1108			 audit_feature_names[which], !!old_feature, !!new_feature,
1109			 !!old_lock, !!new_lock, res);
1110	audit_log_end(ab);
1111}
1112
1113static int audit_set_feature(struct sk_buff *skb)
1114{
1115	struct audit_features *uaf;
1116	int i;
1117
1118	BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
1119	uaf = nlmsg_data(nlmsg_hdr(skb));
1120
1121	/* if there is ever a version 2 we should handle that here */
1122
1123	for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1124		u32 feature = AUDIT_FEATURE_TO_MASK(i);
1125		u32 old_feature, new_feature, old_lock, new_lock;
1126
1127		/* if we are not changing this feature, move along */
1128		if (!(feature & uaf->mask))
1129			continue;
1130
1131		old_feature = af.features & feature;
1132		new_feature = uaf->features & feature;
1133		new_lock = (uaf->lock | af.lock) & feature;
1134		old_lock = af.lock & feature;
1135
1136		/* are we changing a locked feature? */
1137		if (old_lock && (new_feature != old_feature)) {
1138			audit_log_feature_change(i, old_feature, new_feature,
1139						 old_lock, new_lock, 0);
1140			return -EPERM;
1141		}
1142	}
1143	/* nothing invalid, do the changes */
1144	for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1145		u32 feature = AUDIT_FEATURE_TO_MASK(i);
1146		u32 old_feature, new_feature, old_lock, new_lock;
1147
1148		/* if we are not changing this feature, move along */
1149		if (!(feature & uaf->mask))
1150			continue;
1151
1152		old_feature = af.features & feature;
1153		new_feature = uaf->features & feature;
1154		old_lock = af.lock & feature;
1155		new_lock = (uaf->lock | af.lock) & feature;
1156
1157		if (new_feature != old_feature)
1158			audit_log_feature_change(i, old_feature, new_feature,
1159						 old_lock, new_lock, 1);
1160
1161		if (new_feature)
1162			af.features |= feature;
1163		else
1164			af.features &= ~feature;
1165		af.lock |= new_lock;
1166	}
1167
1168	return 0;
1169}
1170
1171static int audit_replace(struct pid *pid)
1172{
1173	pid_t pvnr;
1174	struct sk_buff *skb;
1175
1176	pvnr = pid_vnr(pid);
1177	skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
1178	if (!skb)
1179		return -ENOMEM;
1180	return auditd_send_unicast_skb(skb);
1181}
1182
1183static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
1184{
1185	u32			seq;
1186	void			*data;
1187	int			err;
1188	struct audit_buffer	*ab;
1189	u16			msg_type = nlh->nlmsg_type;
1190	struct audit_sig_info   *sig_data;
1191	char			*ctx = NULL;
1192	u32			len;
1193
1194	err = audit_netlink_ok(skb, msg_type);
1195	if (err)
1196		return err;
1197
 
 
 
 
 
 
 
 
 
 
1198	seq  = nlh->nlmsg_seq;
1199	data = nlmsg_data(nlh);
1200
1201	switch (msg_type) {
1202	case AUDIT_GET: {
1203		struct audit_status	s;
1204		memset(&s, 0, sizeof(s));
1205		s.enabled		= audit_enabled;
1206		s.failure		= audit_failure;
1207		/* NOTE: use pid_vnr() so the PID is relative to the current
1208		 *       namespace */
1209		s.pid			= auditd_pid_vnr();
1210		s.rate_limit		= audit_rate_limit;
1211		s.backlog_limit		= audit_backlog_limit;
1212		s.lost			= atomic_read(&audit_lost);
1213		s.backlog		= skb_queue_len(&audit_queue);
1214		s.feature_bitmap	= AUDIT_FEATURE_BITMAP_ALL;
1215		s.backlog_wait_time	= audit_backlog_wait_time;
1216		audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
1217		break;
1218	}
1219	case AUDIT_SET: {
1220		struct audit_status	s;
1221		memset(&s, 0, sizeof(s));
1222		/* guard against past and future API changes */
1223		memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
1224		if (s.mask & AUDIT_STATUS_ENABLED) {
1225			err = audit_set_enabled(s.enabled);
1226			if (err < 0)
1227				return err;
1228		}
1229		if (s.mask & AUDIT_STATUS_FAILURE) {
1230			err = audit_set_failure(s.failure);
1231			if (err < 0)
1232				return err;
1233		}
1234		if (s.mask & AUDIT_STATUS_PID) {
1235			/* NOTE: we are using the vnr PID functions below
1236			 *       because the s.pid value is relative to the
1237			 *       namespace of the caller; at present this
1238			 *       doesn't matter much since you can really only
1239			 *       run auditd from the initial pid namespace, but
1240			 *       something to keep in mind if this changes */
1241			pid_t new_pid = s.pid;
1242			pid_t auditd_pid;
1243			struct pid *req_pid = task_tgid(current);
1244
1245			/* Sanity check - PID values must match. Setting
1246			 * pid to 0 is how auditd ends auditing. */
1247			if (new_pid && (new_pid != pid_vnr(req_pid)))
1248				return -EINVAL;
1249
1250			/* test the auditd connection */
1251			audit_replace(req_pid);
1252
1253			auditd_pid = auditd_pid_vnr();
1254			if (auditd_pid) {
1255				/* replacing a healthy auditd is not allowed */
1256				if (new_pid) {
1257					audit_log_config_change("audit_pid",
1258							new_pid, auditd_pid, 0);
1259					return -EEXIST;
1260				}
1261				/* only current auditd can unregister itself */
1262				if (pid_vnr(req_pid) != auditd_pid) {
1263					audit_log_config_change("audit_pid",
1264							new_pid, auditd_pid, 0);
1265					return -EACCES;
1266				}
1267			}
1268
1269			if (new_pid) {
1270				/* register a new auditd connection */
1271				err = auditd_set(req_pid,
1272						 NETLINK_CB(skb).portid,
1273						 sock_net(NETLINK_CB(skb).sk));
1274				if (audit_enabled != AUDIT_OFF)
1275					audit_log_config_change("audit_pid",
1276								new_pid,
1277								auditd_pid,
1278								err ? 0 : 1);
1279				if (err)
1280					return err;
1281
1282				/* try to process any backlog */
1283				wake_up_interruptible(&kauditd_wait);
1284			} else {
1285				if (audit_enabled != AUDIT_OFF)
1286					audit_log_config_change("audit_pid",
1287								new_pid,
1288								auditd_pid, 1);
1289
1290				/* unregister the auditd connection */
1291				auditd_reset(NULL);
1292			}
 
 
 
 
 
1293		}
1294		if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
1295			err = audit_set_rate_limit(s.rate_limit);
1296			if (err < 0)
1297				return err;
1298		}
1299		if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
1300			err = audit_set_backlog_limit(s.backlog_limit);
1301			if (err < 0)
1302				return err;
1303		}
1304		if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
1305			if (sizeof(s) > (size_t)nlh->nlmsg_len)
1306				return -EINVAL;
1307			if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
1308				return -EINVAL;
1309			err = audit_set_backlog_wait_time(s.backlog_wait_time);
1310			if (err < 0)
1311				return err;
1312		}
1313		if (s.mask == AUDIT_STATUS_LOST) {
1314			u32 lost = atomic_xchg(&audit_lost, 0);
1315
1316			audit_log_config_change("lost", 0, lost, 1);
1317			return lost;
1318		}
1319		break;
1320	}
1321	case AUDIT_GET_FEATURE:
1322		err = audit_get_feature(skb);
1323		if (err)
1324			return err;
1325		break;
1326	case AUDIT_SET_FEATURE:
1327		err = audit_set_feature(skb);
1328		if (err)
1329			return err;
1330		break;
1331	case AUDIT_USER:
1332	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1333	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1334		if (!audit_enabled && msg_type != AUDIT_USER_AVC)
1335			return 0;
1336
1337		err = audit_filter(msg_type, AUDIT_FILTER_USER);
1338		if (err == 1) { /* match or error */
1339			err = 0;
1340			if (msg_type == AUDIT_USER_TTY) {
1341				err = tty_audit_push();
1342				if (err)
1343					break;
1344			}
 
1345			audit_log_common_recv_msg(&ab, msg_type);
1346			if (msg_type != AUDIT_USER_TTY)
1347				audit_log_format(ab, " msg='%.*s'",
1348						 AUDIT_MESSAGE_TEXT_MAX,
1349						 (char *)data);
1350			else {
1351				int size;
1352
1353				audit_log_format(ab, " data=");
1354				size = nlmsg_len(nlh);
1355				if (size > 0 &&
1356				    ((unsigned char *)data)[size - 1] == '\0')
1357					size--;
1358				audit_log_n_untrustedstring(ab, data, size);
1359			}
 
1360			audit_log_end(ab);
 
1361		}
1362		break;
1363	case AUDIT_ADD_RULE:
1364	case AUDIT_DEL_RULE:
1365		if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
1366			return -EINVAL;
1367		if (audit_enabled == AUDIT_LOCKED) {
1368			audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1369			audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
1370			audit_log_end(ab);
1371			return -EPERM;
1372		}
1373		err = audit_rule_change(msg_type, seq, data, nlmsg_len(nlh));
 
1374		break;
1375	case AUDIT_LIST_RULES:
1376		err = audit_list_rules_send(skb, seq);
1377		break;
1378	case AUDIT_TRIM:
1379		audit_trim_trees();
1380		audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1381		audit_log_format(ab, " op=trim res=1");
1382		audit_log_end(ab);
1383		break;
1384	case AUDIT_MAKE_EQUIV: {
1385		void *bufp = data;
1386		u32 sizes[2];
1387		size_t msglen = nlmsg_len(nlh);
1388		char *old, *new;
1389
1390		err = -EINVAL;
1391		if (msglen < 2 * sizeof(u32))
1392			break;
1393		memcpy(sizes, bufp, 2 * sizeof(u32));
1394		bufp += 2 * sizeof(u32);
1395		msglen -= 2 * sizeof(u32);
1396		old = audit_unpack_string(&bufp, &msglen, sizes[0]);
1397		if (IS_ERR(old)) {
1398			err = PTR_ERR(old);
1399			break;
1400		}
1401		new = audit_unpack_string(&bufp, &msglen, sizes[1]);
1402		if (IS_ERR(new)) {
1403			err = PTR_ERR(new);
1404			kfree(old);
1405			break;
1406		}
1407		/* OK, here comes... */
1408		err = audit_tag_tree(old, new);
1409
1410		audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1411
1412		audit_log_format(ab, " op=make_equiv old=");
1413		audit_log_untrustedstring(ab, old);
1414		audit_log_format(ab, " new=");
1415		audit_log_untrustedstring(ab, new);
1416		audit_log_format(ab, " res=%d", !err);
1417		audit_log_end(ab);
1418		kfree(old);
1419		kfree(new);
1420		break;
1421	}
1422	case AUDIT_SIGNAL_INFO:
1423		len = 0;
1424		if (audit_sig_sid) {
1425			err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1426			if (err)
1427				return err;
1428		}
1429		sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
1430		if (!sig_data) {
1431			if (audit_sig_sid)
1432				security_release_secctx(ctx, len);
1433			return -ENOMEM;
1434		}
1435		sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1436		sig_data->pid = audit_sig_pid;
1437		if (audit_sig_sid) {
1438			memcpy(sig_data->ctx, ctx, len);
1439			security_release_secctx(ctx, len);
1440		}
1441		audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1442				 sig_data, sizeof(*sig_data) + len);
1443		kfree(sig_data);
1444		break;
1445	case AUDIT_TTY_GET: {
1446		struct audit_tty_status s;
1447		unsigned int t;
1448
1449		t = READ_ONCE(current->signal->audit_tty);
1450		s.enabled = t & AUDIT_TTY_ENABLE;
1451		s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1452
1453		audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1454		break;
1455	}
1456	case AUDIT_TTY_SET: {
1457		struct audit_tty_status s, old;
1458		struct audit_buffer	*ab;
1459		unsigned int t;
1460
1461		memset(&s, 0, sizeof(s));
1462		/* guard against past and future API changes */
1463		memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
1464		/* check if new data is valid */
1465		if ((s.enabled != 0 && s.enabled != 1) ||
1466		    (s.log_passwd != 0 && s.log_passwd != 1))
1467			err = -EINVAL;
1468
1469		if (err)
1470			t = READ_ONCE(current->signal->audit_tty);
1471		else {
1472			t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1473			t = xchg(&current->signal->audit_tty, t);
1474		}
1475		old.enabled = t & AUDIT_TTY_ENABLE;
1476		old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1477
1478		audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1479		audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1480				 " old-log_passwd=%d new-log_passwd=%d res=%d",
1481				 old.enabled, s.enabled, old.log_passwd,
1482				 s.log_passwd, !err);
1483		audit_log_end(ab);
1484		break;
1485	}
1486	default:
1487		err = -EINVAL;
1488		break;
1489	}
1490
1491	return err < 0 ? err : 0;
1492}
1493
1494/**
1495 * audit_receive - receive messages from a netlink control socket
1496 * @skb: the message buffer
1497 *
1498 * Parse the provided skb and deal with any messages that may be present,
1499 * malformed skbs are discarded.
1500 */
1501static void audit_receive(struct sk_buff  *skb)
1502{
1503	struct nlmsghdr *nlh;
1504	/*
1505	 * len MUST be signed for nlmsg_next to be able to dec it below 0
1506	 * if the nlmsg_len was not aligned
1507	 */
1508	int len;
1509	int err;
1510
1511	nlh = nlmsg_hdr(skb);
1512	len = skb->len;
1513
1514	audit_ctl_lock();
1515	while (nlmsg_ok(nlh, len)) {
1516		err = audit_receive_msg(skb, nlh);
1517		/* if err or if this message says it wants a response */
1518		if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1519			netlink_ack(skb, nlh, err, NULL);
1520
1521		nlh = nlmsg_next(nlh, &len);
1522	}
1523	audit_ctl_unlock();
 
 
 
 
 
 
 
1524}
1525
1526/* Run custom bind function on netlink socket group connect or bind requests. */
1527static int audit_bind(struct net *net, int group)
1528{
1529	if (!capable(CAP_AUDIT_READ))
1530		return -EPERM;
1531
1532	return 0;
1533}
1534
1535static int __net_init audit_net_init(struct net *net)
1536{
1537	struct netlink_kernel_cfg cfg = {
1538		.input	= audit_receive,
1539		.bind	= audit_bind,
1540		.flags	= NL_CFG_F_NONROOT_RECV,
1541		.groups	= AUDIT_NLGRP_MAX,
1542	};
1543
1544	struct audit_net *aunet = net_generic(net, audit_net_id);
1545
1546	aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1547	if (aunet->sk == NULL) {
1548		audit_panic("cannot initialize netlink socket in namespace");
1549		return -ENOMEM;
1550	}
1551	aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
1552
1553	return 0;
1554}
1555
1556static void __net_exit audit_net_exit(struct net *net)
1557{
1558	struct audit_net *aunet = net_generic(net, audit_net_id);
 
 
 
 
 
1559
1560	/* NOTE: you would think that we would want to check the auditd
1561	 * connection and potentially reset it here if it lives in this
1562	 * namespace, but since the auditd connection tracking struct holds a
1563	 * reference to this namespace (see auditd_set()) we are only ever
1564	 * going to get here after that connection has been released */
1565
1566	netlink_kernel_release(aunet->sk);
1567}
1568
1569static struct pernet_operations audit_net_ops __net_initdata = {
1570	.init = audit_net_init,
1571	.exit = audit_net_exit,
1572	.id = &audit_net_id,
1573	.size = sizeof(struct audit_net),
1574};
1575
1576/* Initialize audit support at boot time. */
1577static int __init audit_init(void)
1578{
1579	int i;
1580
1581	if (audit_initialized == AUDIT_DISABLED)
1582		return 0;
1583
1584	audit_buffer_cache = kmem_cache_create("audit_buffer",
1585					       sizeof(struct audit_buffer),
1586					       0, SLAB_PANIC, NULL);
1587
1588	skb_queue_head_init(&audit_queue);
1589	skb_queue_head_init(&audit_retry_queue);
1590	skb_queue_head_init(&audit_hold_queue);
1591
1592	for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1593		INIT_LIST_HEAD(&audit_inode_hash[i]);
1594
1595	mutex_init(&audit_cmd_mutex.lock);
1596	audit_cmd_mutex.owner = NULL;
1597
1598	pr_info("initializing netlink subsys (%s)\n",
1599		audit_default ? "enabled" : "disabled");
1600	register_pernet_subsys(&audit_net_ops);
1601
 
 
1602	audit_initialized = AUDIT_INITIALIZED;
 
 
1603
1604	kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
1605	if (IS_ERR(kauditd_task)) {
1606		int err = PTR_ERR(kauditd_task);
1607		panic("audit: failed to start the kauditd thread (%d)\n", err);
1608	}
1609
1610	audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
1611		"state=initialized audit_enabled=%u res=1",
1612		 audit_enabled);
1613
1614	return 0;
1615}
1616postcore_initcall(audit_init);
1617
1618/*
1619 * Process kernel command-line parameter at boot time.
1620 * audit={0|off} or audit={1|on}.
1621 */
1622static int __init audit_enable(char *str)
1623{
1624	if (!strcasecmp(str, "off") || !strcmp(str, "0"))
1625		audit_default = AUDIT_OFF;
1626	else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
1627		audit_default = AUDIT_ON;
1628	else {
1629		pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
1630		audit_default = AUDIT_ON;
1631	}
1632
1633	if (audit_default == AUDIT_OFF)
1634		audit_initialized = AUDIT_DISABLED;
1635	if (audit_set_enabled(audit_default))
1636		pr_err("audit: error setting audit state (%d)\n",
1637		       audit_default);
1638
1639	pr_info("%s\n", audit_default ?
1640		"enabled (after initialization)" : "disabled (until reboot)");
1641
1642	return 1;
1643}
1644__setup("audit=", audit_enable);
1645
1646/* Process kernel command-line parameter at boot time.
1647 * audit_backlog_limit=<n> */
1648static int __init audit_backlog_limit_set(char *str)
1649{
1650	u32 audit_backlog_limit_arg;
1651
1652	pr_info("audit_backlog_limit: ");
1653	if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1654		pr_cont("using default of %u, unable to parse %s\n",
1655			audit_backlog_limit, str);
1656		return 1;
1657	}
1658
1659	audit_backlog_limit = audit_backlog_limit_arg;
1660	pr_cont("%d\n", audit_backlog_limit);
1661
1662	return 1;
1663}
1664__setup("audit_backlog_limit=", audit_backlog_limit_set);
1665
1666static void audit_buffer_free(struct audit_buffer *ab)
1667{
 
 
1668	if (!ab)
1669		return;
1670
1671	kfree_skb(ab->skb);
1672	kmem_cache_free(audit_buffer_cache, ab);
 
 
 
 
 
 
 
1673}
1674
1675static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
1676					       gfp_t gfp_mask, int type)
1677{
1678	struct audit_buffer *ab;
 
 
1679
1680	ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
1681	if (!ab)
1682		return NULL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1683
1684	ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1685	if (!ab->skb)
1686		goto err;
1687	if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
1688		goto err;
1689
1690	ab->ctx = ctx;
1691	ab->gfp_mask = gfp_mask;
 
1692
1693	return ab;
1694
 
 
 
1695err:
1696	audit_buffer_free(ab);
1697	return NULL;
1698}
1699
1700/**
1701 * audit_serial - compute a serial number for the audit record
1702 *
1703 * Compute a serial number for the audit record.  Audit records are
1704 * written to user-space as soon as they are generated, so a complete
1705 * audit record may be written in several pieces.  The timestamp of the
1706 * record and this serial number are used by the user-space tools to
1707 * determine which pieces belong to the same audit record.  The
1708 * (timestamp,serial) tuple is unique for each syscall and is live from
1709 * syscall entry to syscall exit.
1710 *
1711 * NOTE: Another possibility is to store the formatted records off the
1712 * audit context (for those records that have a context), and emit them
1713 * all at syscall exit.  However, this could delay the reporting of
1714 * significant errors until syscall exit (or never, if the system
1715 * halts).
1716 */
1717unsigned int audit_serial(void)
1718{
1719	static atomic_t serial = ATOMIC_INIT(0);
1720
1721	return atomic_add_return(1, &serial);
1722}
1723
1724static inline void audit_get_stamp(struct audit_context *ctx,
1725				   struct timespec64 *t, unsigned int *serial)
1726{
1727	if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1728		*t = current_kernel_time64();
1729		*serial = audit_serial();
1730	}
1731}
1732
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1733/**
1734 * audit_log_start - obtain an audit buffer
1735 * @ctx: audit_context (may be NULL)
1736 * @gfp_mask: type of allocation
1737 * @type: audit message type
1738 *
1739 * Returns audit_buffer pointer on success or NULL on error.
1740 *
1741 * Obtain an audit buffer.  This routine does locking to obtain the
1742 * audit buffer, but then no locking is required for calls to
1743 * audit_log_*format.  If the task (ctx) is a task that is currently in a
1744 * syscall, then the syscall is marked as auditable and an audit record
1745 * will be written at syscall exit.  If there is no associated task, then
1746 * task context (ctx) should be NULL.
1747 */
1748struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1749				     int type)
1750{
1751	struct audit_buffer *ab;
1752	struct timespec64 t;
1753	unsigned int uninitialized_var(serial);
 
 
 
1754
1755	if (audit_initialized != AUDIT_INITIALIZED)
1756		return NULL;
1757
1758	if (unlikely(!audit_filter(type, AUDIT_FILTER_TYPE)))
1759		return NULL;
1760
1761	/* NOTE: don't ever fail/sleep on these two conditions:
1762	 * 1. auditd generated record - since we need auditd to drain the
1763	 *    queue; also, when we are checking for auditd, compare PIDs using
1764	 *    task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1765	 *    using a PID anchored in the caller's namespace
1766	 * 2. generator holding the audit_cmd_mutex - we don't want to block
1767	 *    while holding the mutex */
1768	if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
1769		long stime = audit_backlog_wait_time;
1770
1771		while (audit_backlog_limit &&
1772		       (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1773			/* wake kauditd to try and flush the queue */
1774			wake_up_interruptible(&kauditd_wait);
1775
1776			/* sleep if we are allowed and we haven't exhausted our
1777			 * backlog wait limit */
1778			if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
1779				DECLARE_WAITQUEUE(wait, current);
1780
1781				add_wait_queue_exclusive(&audit_backlog_wait,
1782							 &wait);
1783				set_current_state(TASK_UNINTERRUPTIBLE);
1784				stime = schedule_timeout(stime);
1785				remove_wait_queue(&audit_backlog_wait, &wait);
1786			} else {
1787				if (audit_rate_check() && printk_ratelimit())
1788					pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1789						skb_queue_len(&audit_queue),
1790						audit_backlog_limit);
1791				audit_log_lost("backlog limit exceeded");
1792				return NULL;
1793			}
1794		}
 
 
 
 
 
 
 
 
1795	}
1796
 
 
 
1797	ab = audit_buffer_alloc(ctx, gfp_mask, type);
1798	if (!ab) {
1799		audit_log_lost("out of memory in audit_log_start");
1800		return NULL;
1801	}
1802
1803	audit_get_stamp(ab->ctx, &t, &serial);
1804	audit_log_format(ab, "audit(%llu.%03lu:%u): ",
1805			 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
1806
 
 
1807	return ab;
1808}
1809
1810/**
1811 * audit_expand - expand skb in the audit buffer
1812 * @ab: audit_buffer
1813 * @extra: space to add at tail of the skb
1814 *
1815 * Returns 0 (no space) on failed expansion, or available space if
1816 * successful.
1817 */
1818static inline int audit_expand(struct audit_buffer *ab, int extra)
1819{
1820	struct sk_buff *skb = ab->skb;
1821	int oldtail = skb_tailroom(skb);
1822	int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1823	int newtail = skb_tailroom(skb);
1824
1825	if (ret < 0) {
1826		audit_log_lost("out of memory in audit_expand");
1827		return 0;
1828	}
1829
1830	skb->truesize += newtail - oldtail;
1831	return newtail;
1832}
1833
1834/*
1835 * Format an audit message into the audit buffer.  If there isn't enough
1836 * room in the audit buffer, more room will be allocated and vsnprint
1837 * will be called a second time.  Currently, we assume that a printk
1838 * can't format message larger than 1024 bytes, so we don't either.
1839 */
1840static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1841			      va_list args)
1842{
1843	int len, avail;
1844	struct sk_buff *skb;
1845	va_list args2;
1846
1847	if (!ab)
1848		return;
1849
1850	BUG_ON(!ab->skb);
1851	skb = ab->skb;
1852	avail = skb_tailroom(skb);
1853	if (avail == 0) {
1854		avail = audit_expand(ab, AUDIT_BUFSIZ);
1855		if (!avail)
1856			goto out;
1857	}
1858	va_copy(args2, args);
1859	len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1860	if (len >= avail) {
1861		/* The printk buffer is 1024 bytes long, so if we get
1862		 * here and AUDIT_BUFSIZ is at least 1024, then we can
1863		 * log everything that printk could have logged. */
1864		avail = audit_expand(ab,
1865			max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1866		if (!avail)
1867			goto out_va_end;
1868		len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1869	}
1870	if (len > 0)
1871		skb_put(skb, len);
1872out_va_end:
1873	va_end(args2);
1874out:
1875	return;
1876}
1877
1878/**
1879 * audit_log_format - format a message into the audit buffer.
1880 * @ab: audit_buffer
1881 * @fmt: format string
1882 * @...: optional parameters matching @fmt string
1883 *
1884 * All the work is done in audit_log_vformat.
1885 */
1886void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1887{
1888	va_list args;
1889
1890	if (!ab)
1891		return;
1892	va_start(args, fmt);
1893	audit_log_vformat(ab, fmt, args);
1894	va_end(args);
1895}
1896
1897/**
1898 * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
1899 * @ab: the audit_buffer
1900 * @buf: buffer to convert to hex
1901 * @len: length of @buf to be converted
1902 *
1903 * No return value; failure to expand is silently ignored.
1904 *
1905 * This function will take the passed buf and convert it into a string of
1906 * ascii hex digits. The new string is placed onto the skb.
1907 */
1908void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1909		size_t len)
1910{
1911	int i, avail, new_len;
1912	unsigned char *ptr;
1913	struct sk_buff *skb;
1914
1915	if (!ab)
1916		return;
1917
1918	BUG_ON(!ab->skb);
1919	skb = ab->skb;
1920	avail = skb_tailroom(skb);
1921	new_len = len<<1;
1922	if (new_len >= avail) {
1923		/* Round the buffer request up to the next multiple */
1924		new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1925		avail = audit_expand(ab, new_len);
1926		if (!avail)
1927			return;
1928	}
1929
1930	ptr = skb_tail_pointer(skb);
1931	for (i = 0; i < len; i++)
1932		ptr = hex_byte_pack_upper(ptr, buf[i]);
1933	*ptr = 0;
1934	skb_put(skb, len << 1); /* new string is twice the old string */
1935}
1936
1937/*
1938 * Format a string of no more than slen characters into the audit buffer,
1939 * enclosed in quote marks.
1940 */
1941void audit_log_n_string(struct audit_buffer *ab, const char *string,
1942			size_t slen)
1943{
1944	int avail, new_len;
1945	unsigned char *ptr;
1946	struct sk_buff *skb;
1947
1948	if (!ab)
1949		return;
1950
1951	BUG_ON(!ab->skb);
1952	skb = ab->skb;
1953	avail = skb_tailroom(skb);
1954	new_len = slen + 3;	/* enclosing quotes + null terminator */
1955	if (new_len > avail) {
1956		avail = audit_expand(ab, new_len);
1957		if (!avail)
1958			return;
1959	}
1960	ptr = skb_tail_pointer(skb);
1961	*ptr++ = '"';
1962	memcpy(ptr, string, slen);
1963	ptr += slen;
1964	*ptr++ = '"';
1965	*ptr = 0;
1966	skb_put(skb, slen + 2);	/* don't include null terminator */
1967}
1968
1969/**
1970 * audit_string_contains_control - does a string need to be logged in hex
1971 * @string: string to be checked
1972 * @len: max length of the string to check
1973 */
1974bool audit_string_contains_control(const char *string, size_t len)
1975{
1976	const unsigned char *p;
1977	for (p = string; p < (const unsigned char *)string + len; p++) {
1978		if (*p == '"' || *p < 0x21 || *p > 0x7e)
1979			return true;
1980	}
1981	return false;
1982}
1983
1984/**
1985 * audit_log_n_untrustedstring - log a string that may contain random characters
1986 * @ab: audit_buffer
1987 * @len: length of string (not including trailing null)
1988 * @string: string to be logged
1989 *
1990 * This code will escape a string that is passed to it if the string
1991 * contains a control character, unprintable character, double quote mark,
1992 * or a space. Unescaped strings will start and end with a double quote mark.
1993 * Strings that are escaped are printed in hex (2 digits per char).
1994 *
1995 * The caller specifies the number of characters in the string to log, which may
1996 * or may not be the entire string.
1997 */
1998void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
1999				 size_t len)
2000{
2001	if (audit_string_contains_control(string, len))
2002		audit_log_n_hex(ab, string, len);
2003	else
2004		audit_log_n_string(ab, string, len);
2005}
2006
2007/**
2008 * audit_log_untrustedstring - log a string that may contain random characters
2009 * @ab: audit_buffer
2010 * @string: string to be logged
2011 *
2012 * Same as audit_log_n_untrustedstring(), except that strlen is used to
2013 * determine string length.
2014 */
2015void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
2016{
2017	audit_log_n_untrustedstring(ab, string, strlen(string));
2018}
2019
2020/* This is a helper-function to print the escaped d_path */
2021void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
2022		      const struct path *path)
2023{
2024	char *p, *pathname;
2025
2026	if (prefix)
2027		audit_log_format(ab, "%s", prefix);
2028
2029	/* We will allow 11 spaces for ' (deleted)' to be appended */
2030	pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
2031	if (!pathname) {
2032		audit_log_string(ab, "<no_memory>");
2033		return;
2034	}
2035	p = d_path(path, pathname, PATH_MAX+11);
2036	if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
2037		/* FIXME: can we save some information here? */
2038		audit_log_string(ab, "<too_long>");
2039	} else
2040		audit_log_untrustedstring(ab, p);
2041	kfree(pathname);
2042}
2043
2044void audit_log_session_info(struct audit_buffer *ab)
2045{
2046	unsigned int sessionid = audit_get_sessionid(current);
2047	uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
2048
2049	audit_log_format(ab, " auid=%u ses=%u", auid, sessionid);
2050}
2051
2052void audit_log_key(struct audit_buffer *ab, char *key)
2053{
2054	audit_log_format(ab, " key=");
2055	if (key)
2056		audit_log_untrustedstring(ab, key);
2057	else
2058		audit_log_format(ab, "(null)");
2059}
2060
2061void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
2062{
2063	int i;
2064
2065	audit_log_format(ab, " %s=", prefix);
2066	CAP_FOR_EACH_U32(i) {
2067		audit_log_format(ab, "%08x",
2068				 cap->cap[CAP_LAST_U32 - i]);
2069	}
2070}
2071
2072static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
2073{
2074	audit_log_cap(ab, "cap_fp", &name->fcap.permitted);
2075	audit_log_cap(ab, "cap_fi", &name->fcap.inheritable);
2076	audit_log_format(ab, " cap_fe=%d cap_fver=%x",
2077			 name->fcap.fE, name->fcap_ver);
 
 
 
 
 
 
 
 
 
 
 
 
2078}
2079
2080static inline int audit_copy_fcaps(struct audit_names *name,
2081				   const struct dentry *dentry)
2082{
2083	struct cpu_vfs_cap_data caps;
2084	int rc;
2085
2086	if (!dentry)
2087		return 0;
2088
2089	rc = get_vfs_caps_from_disk(dentry, &caps);
2090	if (rc)
2091		return rc;
2092
2093	name->fcap.permitted = caps.permitted;
2094	name->fcap.inheritable = caps.inheritable;
2095	name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
2096	name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
2097				VFS_CAP_REVISION_SHIFT;
2098
2099	return 0;
2100}
2101
2102/* Copy inode data into an audit_names. */
2103void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
2104		      struct inode *inode)
2105{
2106	name->ino   = inode->i_ino;
2107	name->dev   = inode->i_sb->s_dev;
2108	name->mode  = inode->i_mode;
2109	name->uid   = inode->i_uid;
2110	name->gid   = inode->i_gid;
2111	name->rdev  = inode->i_rdev;
2112	security_inode_getsecid(inode, &name->osid);
2113	audit_copy_fcaps(name, dentry);
2114}
2115
2116/**
2117 * audit_log_name - produce AUDIT_PATH record from struct audit_names
2118 * @context: audit_context for the task
2119 * @n: audit_names structure with reportable details
2120 * @path: optional path to report instead of audit_names->name
2121 * @record_num: record number to report when handling a list of names
2122 * @call_panic: optional pointer to int that will be updated if secid fails
2123 */
2124void audit_log_name(struct audit_context *context, struct audit_names *n,
2125		    const struct path *path, int record_num, int *call_panic)
2126{
2127	struct audit_buffer *ab;
2128	ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
2129	if (!ab)
2130		return;
2131
2132	audit_log_format(ab, "item=%d", record_num);
2133
2134	if (path)
2135		audit_log_d_path(ab, " name=", path);
2136	else if (n->name) {
2137		switch (n->name_len) {
2138		case AUDIT_NAME_FULL:
2139			/* log the full path */
2140			audit_log_format(ab, " name=");
2141			audit_log_untrustedstring(ab, n->name->name);
2142			break;
2143		case 0:
2144			/* name was specified as a relative path and the
2145			 * directory component is the cwd */
2146			audit_log_d_path(ab, " name=", &context->pwd);
2147			break;
2148		default:
2149			/* log the name's directory component */
2150			audit_log_format(ab, " name=");
2151			audit_log_n_untrustedstring(ab, n->name->name,
2152						    n->name_len);
2153		}
2154	} else
2155		audit_log_format(ab, " name=(null)");
2156
2157	if (n->ino != AUDIT_INO_UNSET)
2158		audit_log_format(ab, " inode=%lu"
2159				 " dev=%02x:%02x mode=%#ho"
2160				 " ouid=%u ogid=%u rdev=%02x:%02x",
2161				 n->ino,
2162				 MAJOR(n->dev),
2163				 MINOR(n->dev),
2164				 n->mode,
2165				 from_kuid(&init_user_ns, n->uid),
2166				 from_kgid(&init_user_ns, n->gid),
2167				 MAJOR(n->rdev),
2168				 MINOR(n->rdev));
2169	if (n->osid != 0) {
2170		char *ctx = NULL;
2171		u32 len;
2172		if (security_secid_to_secctx(
2173			n->osid, &ctx, &len)) {
2174			audit_log_format(ab, " osid=%u", n->osid);
2175			if (call_panic)
2176				*call_panic = 2;
2177		} else {
2178			audit_log_format(ab, " obj=%s", ctx);
2179			security_release_secctx(ctx, len);
2180		}
2181	}
2182
2183	/* log the audit_names record type */
2184	audit_log_format(ab, " nametype=");
2185	switch(n->type) {
2186	case AUDIT_TYPE_NORMAL:
2187		audit_log_format(ab, "NORMAL");
2188		break;
2189	case AUDIT_TYPE_PARENT:
2190		audit_log_format(ab, "PARENT");
2191		break;
2192	case AUDIT_TYPE_CHILD_DELETE:
2193		audit_log_format(ab, "DELETE");
2194		break;
2195	case AUDIT_TYPE_CHILD_CREATE:
2196		audit_log_format(ab, "CREATE");
2197		break;
2198	default:
2199		audit_log_format(ab, "UNKNOWN");
2200		break;
2201	}
2202
2203	audit_log_fcaps(ab, n);
2204	audit_log_end(ab);
2205}
2206
2207int audit_log_task_context(struct audit_buffer *ab)
2208{
2209	char *ctx = NULL;
2210	unsigned len;
2211	int error;
2212	u32 sid;
2213
2214	security_task_getsecid(current, &sid);
2215	if (!sid)
2216		return 0;
2217
2218	error = security_secid_to_secctx(sid, &ctx, &len);
2219	if (error) {
2220		if (error != -EINVAL)
2221			goto error_path;
2222		return 0;
2223	}
2224
2225	audit_log_format(ab, " subj=%s", ctx);
2226	security_release_secctx(ctx, len);
2227	return 0;
2228
2229error_path:
2230	audit_panic("error in audit_log_task_context");
2231	return error;
2232}
2233EXPORT_SYMBOL(audit_log_task_context);
2234
2235void audit_log_d_path_exe(struct audit_buffer *ab,
2236			  struct mm_struct *mm)
2237{
2238	struct file *exe_file;
2239
2240	if (!mm)
2241		goto out_null;
2242
2243	exe_file = get_mm_exe_file(mm);
2244	if (!exe_file)
2245		goto out_null;
2246
2247	audit_log_d_path(ab, " exe=", &exe_file->f_path);
2248	fput(exe_file);
2249	return;
2250out_null:
2251	audit_log_format(ab, " exe=(null)");
2252}
2253
2254struct tty_struct *audit_get_tty(struct task_struct *tsk)
2255{
2256	struct tty_struct *tty = NULL;
2257	unsigned long flags;
2258
2259	spin_lock_irqsave(&tsk->sighand->siglock, flags);
2260	if (tsk->signal)
2261		tty = tty_kref_get(tsk->signal->tty);
2262	spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
2263	return tty;
2264}
2265
2266void audit_put_tty(struct tty_struct *tty)
2267{
2268	tty_kref_put(tty);
2269}
2270
2271void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
2272{
2273	const struct cred *cred;
2274	char comm[sizeof(tsk->comm)];
2275	struct tty_struct *tty;
2276
2277	if (!ab)
2278		return;
2279
2280	/* tsk == current */
2281	cred = current_cred();
2282	tty = audit_get_tty(tsk);
 
 
 
 
 
 
 
2283	audit_log_format(ab,
2284			 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2285			 " euid=%u suid=%u fsuid=%u"
2286			 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2287			 task_ppid_nr(tsk),
2288			 task_tgid_nr(tsk),
2289			 from_kuid(&init_user_ns, audit_get_loginuid(tsk)),
2290			 from_kuid(&init_user_ns, cred->uid),
2291			 from_kgid(&init_user_ns, cred->gid),
2292			 from_kuid(&init_user_ns, cred->euid),
2293			 from_kuid(&init_user_ns, cred->suid),
2294			 from_kuid(&init_user_ns, cred->fsuid),
2295			 from_kgid(&init_user_ns, cred->egid),
2296			 from_kgid(&init_user_ns, cred->sgid),
2297			 from_kgid(&init_user_ns, cred->fsgid),
2298			 tty ? tty_name(tty) : "(none)",
2299			 audit_get_sessionid(tsk));
2300	audit_put_tty(tty);
2301	audit_log_format(ab, " comm=");
2302	audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
 
2303	audit_log_d_path_exe(ab, tsk->mm);
2304	audit_log_task_context(ab);
2305}
2306EXPORT_SYMBOL(audit_log_task_info);
2307
2308/**
2309 * audit_log_link_denied - report a link restriction denial
2310 * @operation: specific link operation
 
2311 */
2312void audit_log_link_denied(const char *operation)
2313{
2314	struct audit_buffer *ab;
 
2315
2316	if (!audit_enabled || audit_dummy_context())
 
2317		return;
2318
2319	/* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
2320	ab = audit_log_start(current->audit_context, GFP_KERNEL,
2321			     AUDIT_ANOM_LINK);
2322	if (!ab)
2323		return;
2324	audit_log_format(ab, "op=%s", operation);
2325	audit_log_task_info(ab, current);
2326	audit_log_format(ab, " res=0");
2327	audit_log_end(ab);
 
 
 
 
 
 
 
2328}
2329
2330/**
2331 * audit_log_end - end one audit record
2332 * @ab: the audit_buffer
2333 *
2334 * We can not do a netlink send inside an irq context because it blocks (last
2335 * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2336 * queue and a tasklet is scheduled to remove them from the queue outside the
2337 * irq context.  May be called in any context.
2338 */
2339void audit_log_end(struct audit_buffer *ab)
2340{
2341	struct sk_buff *skb;
2342	struct nlmsghdr *nlh;
2343
2344	if (!ab)
2345		return;
 
 
 
 
2346
2347	if (audit_rate_check()) {
2348		skb = ab->skb;
2349		ab->skb = NULL;
2350
2351		/* setup the netlink header, see the comments in
2352		 * kauditd_send_multicast_skb() for length quirks */
2353		nlh = nlmsg_hdr(skb);
2354		nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
2355
2356		/* queue the netlink packet and poke the kauditd thread */
2357		skb_queue_tail(&audit_queue, skb);
2358		wake_up_interruptible(&kauditd_wait);
2359	} else
2360		audit_log_lost("rate limit exceeded");
2361
 
 
 
 
 
 
 
 
2362	audit_buffer_free(ab);
2363}
2364
2365/**
2366 * audit_log - Log an audit record
2367 * @ctx: audit context
2368 * @gfp_mask: type of allocation
2369 * @type: audit message type
2370 * @fmt: format string to use
2371 * @...: variable parameters matching the format string
2372 *
2373 * This is a convenience function that calls audit_log_start,
2374 * audit_log_vformat, and audit_log_end.  It may be called
2375 * in any context.
2376 */
2377void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2378	       const char *fmt, ...)
2379{
2380	struct audit_buffer *ab;
2381	va_list args;
2382
2383	ab = audit_log_start(ctx, gfp_mask, type);
2384	if (ab) {
2385		va_start(args, fmt);
2386		audit_log_vformat(ab, fmt, args);
2387		va_end(args);
2388		audit_log_end(ab);
2389	}
2390}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2391
2392EXPORT_SYMBOL(audit_log_start);
2393EXPORT_SYMBOL(audit_log_end);
2394EXPORT_SYMBOL(audit_log_format);
2395EXPORT_SYMBOL(audit_log);