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