kernel/auditfilter.c

   1 /* auditfilter.c -- filtering of audit events
   2  *
   3  * Copyright 2003-2004 Red Hat, Inc.
   4  * Copyright 2005 Hewlett-Packard Development Company, L.P.
   5  * Copyright 2005 IBM Corporation
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/audit.h>
  24 #include <linux/kthread.h>
  25 #include <linux/mutex.h>
  26 #include <linux/fs.h>
  27 #include <linux/namei.h>
  28 #include <linux/netlink.h>
  29 #include <linux/sched.h>
  30 #include <linux/inotify.h>
  31 #include <linux/security.h>
  32 #include "audit.h"
  33
  34 /*
  35  * Locking model:
  36  *
  37  * audit_filter_mutex:
  38  *              Synchronizes writes and blocking reads of audit's filterlist
  39  *              data.  Rcu is used to traverse the filterlist and access
  40  *              contents of structs audit_entry, audit_watch and opaque
  41  *              LSM rules during filtering.  If modified, these structures
  42  *              must be copied and replace their counterparts in the filterlist.
  43  *              An audit_parent struct is not accessed during filtering, so may
  44  *              be written directly provided audit_filter_mutex is held.
  45  */
  46
  47 /*
  48  * Reference counting:
  49  *
  50  * audit_parent: lifetime is from audit_init_parent() to receipt of an IN_IGNORED
  51  *      event.  Each audit_watch holds a reference to its associated parent.
  52  *
  53  * audit_watch: if added to lists, lifetime is from audit_init_watch() to
  54  *      audit_remove_watch().  Additionally, an audit_watch may exist
  55  *      temporarily to assist in searching existing filter data.  Each
  56  *      audit_krule holds a reference to its associated watch.
  57  */
  58
  59 struct audit_parent {
  60         struct list_head        ilist;  /* entry in inotify registration list */
  61         struct list_head        watches; /* associated watches */
  62         struct inotify_watch    wdata;  /* inotify watch data */
  63         unsigned                flags;  /* status flags */
  64 };
  65
  66 /*
  67  * audit_parent status flags:
  68  *
  69  * AUDIT_PARENT_INVALID - set anytime rules/watches are auto-removed due to
  70  * a filesystem event to ensure we're adding audit watches to a valid parent.
  71  * Technically not needed for IN_DELETE_SELF or IN_UNMOUNT events, as we cannot
  72  * receive them while we have nameidata, but must be used for IN_MOVE_SELF which
  73  * we can receive while holding nameidata.
  74  */
  75 #define AUDIT_PARENT_INVALID    0x001
  76
  77 /* Audit filter lists, defined in <linux/audit.h> */
  78 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
  79         LIST_HEAD_INIT(audit_filter_list[0]),
  80         LIST_HEAD_INIT(audit_filter_list[1]),
  81         LIST_HEAD_INIT(audit_filter_list[2]),
  82         LIST_HEAD_INIT(audit_filter_list[3]),
  83         LIST_HEAD_INIT(audit_filter_list[4]),
  84         LIST_HEAD_INIT(audit_filter_list[5]),
  85 #if AUDIT_NR_FILTERS != 6
  86 #error Fix audit_filter_list initialiser
  87 #endif
  88 };
  89
  90 DEFINE_MUTEX(audit_filter_mutex);
  91
  92 /* Inotify events we care about. */
  93 #define AUDIT_IN_WATCH IN_MOVE|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF
  94
  95 void audit_free_parent(struct inotify_watch *i_watch)
  96 {
  97         struct audit_parent *parent;
  98
  99         parent = container_of(i_watch, struct audit_parent, wdata);
 100         WARN_ON(!list_empty(&parent->watches));
 101         kfree(parent);
 102 }
 103
 104 static inline void audit_get_watch(struct audit_watch *watch)
 105 {
 106         atomic_inc(&watch->count);
 107 }
 108
 109 static void audit_put_watch(struct audit_watch *watch)
 110 {
 111         if (atomic_dec_and_test(&watch->count)) {
 112                 WARN_ON(watch->parent);
 113                 WARN_ON(!list_empty(&watch->rules));
 114                 kfree(watch->path);
 115                 kfree(watch);
 116         }
 117 }
 118
 119 static void audit_remove_watch(struct audit_watch *watch)
 120 {
 121         list_del(&watch->wlist);
 122         put_inotify_watch(&watch->parent->wdata);
 123         watch->parent = NULL;
 124         audit_put_watch(watch); /* match initial get */
 125 }
 126
 127 static inline void audit_free_rule(struct audit_entry *e)
 128 {
 129         int i;
 130
 131         /* some rules don't have associated watches */
 132         if (e->rule.watch)
 133                 audit_put_watch(e->rule.watch);
 134         if (e->rule.fields)
 135                 for (i = 0; i < e->rule.field_count; i++) {
 136                         struct audit_field *f = &e->rule.fields[i];
 137                         kfree(f->lsm_str);
 138                         security_audit_rule_free(f->lsm_rule);
 139                 }
 140         kfree(e->rule.fields);
 141         kfree(e->rule.filterkey);
 142         kfree(e);
 143 }
 144
 145 void audit_free_rule_rcu(struct rcu_head *head)
 146 {
 147         struct audit_entry *e = container_of(head, struct audit_entry, rcu);
 148         audit_free_rule(e);
 149 }
 150
 151 /* Initialize a parent watch entry. */
 152 static struct audit_parent *audit_init_parent(struct nameidata *ndp)
 153 {
 154         struct audit_parent *parent;
 155         s32 wd;
 156
 157         parent = kzalloc(sizeof(*parent), GFP_KERNEL);
 158         if (unlikely(!parent))
 159                 return ERR_PTR(-ENOMEM);
 160
 161         INIT_LIST_HEAD(&parent->watches);
 162         parent->flags = 0;
 163
 164         inotify_init_watch(&parent->wdata);
 165         /* grab a ref so inotify watch hangs around until we take audit_filter_mutex */
 166         get_inotify_watch(&parent->wdata);
 167         wd = inotify_add_watch(audit_ih, &parent->wdata,
 168                                ndp->path.dentry->d_inode, AUDIT_IN_WATCH);
 169         if (wd < 0) {
 170                 audit_free_parent(&parent->wdata);
 171                 return ERR_PTR(wd);
 172         }
 173
 174         return parent;
 175 }
 176
 177 /* Initialize a watch entry. */
 178 static struct audit_watch *audit_init_watch(char *path)
 179 {
 180         struct audit_watch *watch;
 181
 182         watch = kzalloc(sizeof(*watch), GFP_KERNEL);
 183         if (unlikely(!watch))
 184                 return ERR_PTR(-ENOMEM);
 185
 186         INIT_LIST_HEAD(&watch->rules);
 187         atomic_set(&watch->count, 1);
 188         watch->path = path;
 189         watch->dev = (dev_t)-1;
 190         watch->ino = (unsigned long)-1;
 191
 192         return watch;
 193 }
 194
 195 /* Initialize an audit filterlist entry. */
 196 static inline struct audit_entry *audit_init_entry(u32 field_count)
 197 {
 198         struct audit_entry *entry;
 199         struct audit_field *fields;
 200
 201         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 202         if (unlikely(!entry))
 203                 return NULL;
 204
 205         fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
 206         if (unlikely(!fields)) {
 207                 kfree(entry);
 208                 return NULL;
 209         }
 210         entry->rule.fields = fields;
 211
 212         return entry;
 213 }
 214
 215 /* Unpack a filter field's string representation from user-space
 216  * buffer. */
 217 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
 218 {
 219         char *str;
 220
 221         if (!*bufp || (len == 0) || (len > *remain))
 222                 return ERR_PTR(-EINVAL);
 223
 224         /* Of the currently implemented string fields, PATH_MAX
 225          * defines the longest valid length.
 226          */
 227         if (len > PATH_MAX)
 228                 return ERR_PTR(-ENAMETOOLONG);
 229
 230         str = kmalloc(len + 1, GFP_KERNEL);
 231         if (unlikely(!str))
 232                 return ERR_PTR(-ENOMEM);
 233
 234         memcpy(str, *bufp, len);
 235         str[len] = 0;
 236         *bufp += len;
 237         *remain -= len;
 238
 239         return str;
 240 }
 241
 242 /* Translate an inode field to kernel respresentation. */
 243 static inline int audit_to_inode(struct audit_krule *krule,
 244                                  struct audit_field *f)
 245 {
 246         if (krule->listnr != AUDIT_FILTER_EXIT ||
 247             krule->watch || krule->inode_f || krule->tree)
 248                 return -EINVAL;
 249
 250         krule->inode_f = f;
 251         return 0;
 252 }
 253
 254 /* Translate a watch string to kernel respresentation. */
 255 static int audit_to_watch(struct audit_krule *krule, char *path, int len,
 256                           u32 op)
 257 {
 258         struct audit_watch *watch;
 259
 260         if (!audit_ih)
 261                 return -EOPNOTSUPP;
 262
 263         if (path[0] != '/' || path[len-1] == '/' ||
 264             krule->listnr != AUDIT_FILTER_EXIT ||
 265             op & ~AUDIT_EQUAL ||
 266             krule->inode_f || krule->watch || krule->tree)
 267                 return -EINVAL;
 268
 269         watch = audit_init_watch(path);
 270         if (IS_ERR(watch))
 271                 return PTR_ERR(watch);
 272
 273         audit_get_watch(watch);
 274         krule->watch = watch;
 275
 276         return 0;
 277 }
 278
 279 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
 280
 281 int __init audit_register_class(int class, unsigned *list)
 282 {
 283         __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
 284         if (!p)
 285                 return -ENOMEM;
 286         while (*list != ~0U) {
 287                 unsigned n = *list++;
 288                 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
 289                         kfree(p);
 290                         return -EINVAL;
 291                 }
 292                 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
 293         }
 294         if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
 295                 kfree(p);
 296                 return -EINVAL;
 297         }
 298         classes[class] = p;
 299         return 0;
 300 }
 301
 302 int audit_match_class(int class, unsigned syscall)
 303 {
 304         if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
 305                 return 0;
 306         if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
 307                 return 0;
 308         return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
 309 }
 310
 311 #ifdef CONFIG_AUDITSYSCALL
 312 static inline int audit_match_class_bits(int class, u32 *mask)
 313 {
 314         int i;
 315
 316         if (classes[class]) {
 317                 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 318                         if (mask[i] & classes[class][i])
 319                                 return 0;
 320         }
 321         return 1;
 322 }
 323
 324 static int audit_match_signal(struct audit_entry *entry)
 325 {
 326         struct audit_field *arch = entry->rule.arch_f;
 327
 328         if (!arch) {
 329                 /* When arch is unspecified, we must check both masks on biarch
 330                  * as syscall number alone is ambiguous. */
 331                 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
 332                                                entry->rule.mask) &&
 333                         audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
 334                                                entry->rule.mask));
 335         }
 336
 337         switch(audit_classify_arch(arch->val)) {
 338         case 0: /* native */
 339                 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
 340                                                entry->rule.mask));
 341         case 1: /* 32bit on biarch */
 342                 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
 343                                                entry->rule.mask));
 344         default:
 345                 return 1;
 346         }
 347 }
 348 #endif
 349
 350 /* Common user-space to kernel rule translation. */
 351 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
 352 {
 353         unsigned listnr;
 354         struct audit_entry *entry;
 355         int i, err;
 356
 357         err = -EINVAL;
 358         listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
 359         switch(listnr) {
 360         default:
 361                 goto exit_err;
 362         case AUDIT_FILTER_USER:
 363         case AUDIT_FILTER_TYPE:
 364 #ifdef CONFIG_AUDITSYSCALL
 365         case AUDIT_FILTER_ENTRY:
 366         case AUDIT_FILTER_EXIT:
 367         case AUDIT_FILTER_TASK:
 368 #endif
 369                 ;
 370         }
 371         if (unlikely(rule->action == AUDIT_POSSIBLE)) {
 372                 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
 373                 goto exit_err;
 374         }
 375         if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
 376                 goto exit_err;
 377         if (rule->field_count > AUDIT_MAX_FIELDS)
 378                 goto exit_err;
 379
 380         err = -ENOMEM;
 381         entry = audit_init_entry(rule->field_count);
 382         if (!entry)
 383                 goto exit_err;
 384
 385         entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
 386         entry->rule.listnr = listnr;
 387         entry->rule.action = rule->action;
 388         entry->rule.field_count = rule->field_count;
 389
 390         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 391                 entry->rule.mask[i] = rule->mask[i];
 392
 393         for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
 394                 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
 395                 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
 396                 __u32 *class;
 397
 398                 if (!(*p & AUDIT_BIT(bit)))
 399                         continue;
 400                 *p &= ~AUDIT_BIT(bit);
 401                 class = classes[i];
 402                 if (class) {
 403                         int j;
 404                         for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
 405                                 entry->rule.mask[j] |= class[j];
 406                 }
 407         }
 408
 409         return entry;
 410
 411 exit_err:
 412         return ERR_PTR(err);
 413 }
 414
 415 /* Translate struct audit_rule to kernel's rule respresentation.
 416  * Exists for backward compatibility with userspace. */
 417 static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
 418 {
 419         struct audit_entry *entry;
 420         struct audit_field *ino_f;
 421         int err = 0;
 422         int i;
 423
 424         entry = audit_to_entry_common(rule);
 425         if (IS_ERR(entry))
 426                 goto exit_nofree;
 427
 428         for (i = 0; i < rule->field_count; i++) {
 429                 struct audit_field *f = &entry->rule.fields[i];
 430
 431                 f->op = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
 432                 f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
 433                 f->val = rule->values[i];
 434
 435                 err = -EINVAL;
 436                 switch(f->type) {
 437                 default:
 438                         goto exit_free;
 439                 case AUDIT_PID:
 440                 case AUDIT_UID:
 441                 case AUDIT_EUID:
 442                 case AUDIT_SUID:
 443                 case AUDIT_FSUID:
 444                 case AUDIT_GID:
 445                 case AUDIT_EGID:
 446                 case AUDIT_SGID:
 447                 case AUDIT_FSGID:
 448                 case AUDIT_LOGINUID:
 449                 case AUDIT_PERS:
 450                 case AUDIT_MSGTYPE:
 451                 case AUDIT_PPID:
 452                 case AUDIT_DEVMAJOR:
 453                 case AUDIT_DEVMINOR:
 454                 case AUDIT_EXIT:
 455                 case AUDIT_SUCCESS:
 456                         /* bit ops are only useful on syscall args */
 457                         if (f->op == AUDIT_BIT_MASK ||
 458                                                 f->op == AUDIT_BIT_TEST) {
 459                                 err = -EINVAL;
 460                                 goto exit_free;
 461                         }
 462                         break;
 463                 case AUDIT_ARG0:
 464                 case AUDIT_ARG1:
 465                 case AUDIT_ARG2:
 466                 case AUDIT_ARG3:
 467                         break;
 468                 /* arch is only allowed to be = or != */
 469                 case AUDIT_ARCH:
 470                         if ((f->op != AUDIT_NOT_EQUAL) && (f->op != AUDIT_EQUAL)
 471                                         && (f->op != AUDIT_NEGATE) && (f->op)) {
 472                                 err = -EINVAL;
 473                                 goto exit_free;
 474                         }
 475                         entry->rule.arch_f = f;
 476                         break;
 477                 case AUDIT_PERM:
 478                         if (f->val & ~15)
 479                                 goto exit_free;
 480                         break;
 481                 case AUDIT_FILETYPE:
 482                         if ((f->val & ~S_IFMT) > S_IFMT)
 483                                 goto exit_free;
 484                         break;
 485                 case AUDIT_INODE:
 486                         err = audit_to_inode(&entry->rule, f);
 487                         if (err)
 488                                 goto exit_free;
 489                         break;
 490                 }
 491
 492                 entry->rule.vers_ops = (f->op & AUDIT_OPERATORS) ? 2 : 1;
 493
 494                 /* Support for legacy operators where
 495                  * AUDIT_NEGATE bit signifies != and otherwise assumes == */
 496                 if (f->op & AUDIT_NEGATE)
 497                         f->op = AUDIT_NOT_EQUAL;
 498                 else if (!f->op)
 499                         f->op = AUDIT_EQUAL;
 500                 else if (f->op == AUDIT_OPERATORS) {
 501                         err = -EINVAL;
 502                         goto exit_free;
 503                 }
 504         }
 505
 506         ino_f = entry->rule.inode_f;
 507         if (ino_f) {
 508                 switch(ino_f->op) {
 509                 case AUDIT_NOT_EQUAL:
 510                         entry->rule.inode_f = NULL;
 511                 case AUDIT_EQUAL:
 512                         break;
 513                 default:
 514                         err = -EINVAL;
 515                         goto exit_free;
 516                 }
 517         }
 518
 519 exit_nofree:
 520         return entry;
 521
 522 exit_free:
 523         audit_free_rule(entry);
 524         return ERR_PTR(err);
 525 }
 526
 527 /* Translate struct audit_rule_data to kernel's rule respresentation. */
 528 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
 529                                                size_t datasz)
 530 {
 531         int err = 0;
 532         struct audit_entry *entry;
 533         struct audit_field *ino_f;
 534         void *bufp;
 535         size_t remain = datasz - sizeof(struct audit_rule_data);
 536         int i;
 537         char *str;
 538
 539         entry = audit_to_entry_common((struct audit_rule *)data);
 540         if (IS_ERR(entry))
 541                 goto exit_nofree;
 542
 543         bufp = data->buf;
 544         entry->rule.vers_ops = 2;
 545         for (i = 0; i < data->field_count; i++) {
 546                 struct audit_field *f = &entry->rule.fields[i];
 547
 548                 err = -EINVAL;
 549                 if (!(data->fieldflags[i] & AUDIT_OPERATORS) ||
 550                     data->fieldflags[i] & ~AUDIT_OPERATORS)
 551                         goto exit_free;
 552
 553                 f->op = data->fieldflags[i] & AUDIT_OPERATORS;
 554                 f->type = data->fields[i];
 555                 f->val = data->values[i];
 556                 f->lsm_str = NULL;
 557                 f->lsm_rule = NULL;
 558                 switch(f->type) {
 559                 case AUDIT_PID:
 560                 case AUDIT_UID:
 561                 case AUDIT_EUID:
 562                 case AUDIT_SUID:
 563                 case AUDIT_FSUID:
 564                 case AUDIT_GID:
 565                 case AUDIT_EGID:
 566                 case AUDIT_SGID:
 567                 case AUDIT_FSGID:
 568                 case AUDIT_LOGINUID:
 569                 case AUDIT_PERS:
 570                 case AUDIT_MSGTYPE:
 571                 case AUDIT_PPID:
 572                 case AUDIT_DEVMAJOR:
 573                 case AUDIT_DEVMINOR:
 574                 case AUDIT_EXIT:
 575                 case AUDIT_SUCCESS:
 576                 case AUDIT_ARG0:
 577                 case AUDIT_ARG1:
 578                 case AUDIT_ARG2:
 579                 case AUDIT_ARG3:
 580                         break;
 581                 case AUDIT_ARCH:
 582                         entry->rule.arch_f = f;
 583                         break;
 584                 case AUDIT_SUBJ_USER:
 585                 case AUDIT_SUBJ_ROLE:
 586                 case AUDIT_SUBJ_TYPE:
 587                 case AUDIT_SUBJ_SEN:
 588                 case AUDIT_SUBJ_CLR:
 589                 case AUDIT_OBJ_USER:
 590                 case AUDIT_OBJ_ROLE:
 591                 case AUDIT_OBJ_TYPE:
 592                 case AUDIT_OBJ_LEV_LOW:
 593                 case AUDIT_OBJ_LEV_HIGH:
 594                         str = audit_unpack_string(&bufp, &remain, f->val);
 595                         if (IS_ERR(str))
 596                                 goto exit_free;
 597                         entry->rule.buflen += f->val;
 598
 599                         err = security_audit_rule_init(f->type, f->op, str,
 600                                                        (void **)&f->lsm_rule);
 601                         /* Keep currently invalid fields around in case they
 602                          * become valid after a policy reload. */
 603                         if (err == -EINVAL) {
 604                                 printk(KERN_WARNING "audit rule for LSM "
 605                                        "\'%s\' is invalid\n",  str);
 606                                 err = 0;
 607                         }
 608                         if (err) {
 609                                 kfree(str);
 610                                 goto exit_free;
 611                         } else
 612                                 f->lsm_str = str;
 613                         break;
 614                 case AUDIT_WATCH:
 615                         str = audit_unpack_string(&bufp, &remain, f->val);
 616                         if (IS_ERR(str))
 617                                 goto exit_free;
 618                         entry->rule.buflen += f->val;
 619
 620                         err = audit_to_watch(&entry->rule, str, f->val, f->op);
 621                         if (err) {
 622                                 kfree(str);
 623                                 goto exit_free;
 624                         }
 625                         break;
 626                 case AUDIT_DIR:
 627                         str = audit_unpack_string(&bufp, &remain, f->val);
 628                         if (IS_ERR(str))
 629                                 goto exit_free;
 630                         entry->rule.buflen += f->val;
 631
 632                         err = audit_make_tree(&entry->rule, str, f->op);
 633                         kfree(str);
 634                         if (err)
 635                                 goto exit_free;
 636                         break;
 637                 case AUDIT_INODE:
 638                         err = audit_to_inode(&entry->rule, f);
 639                         if (err)
 640                                 goto exit_free;
 641                         break;
 642                 case AUDIT_FILTERKEY:
 643                         err = -EINVAL;
 644                         if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
 645                                 goto exit_free;
 646                         str = audit_unpack_string(&bufp, &remain, f->val);
 647                         if (IS_ERR(str))
 648                                 goto exit_free;
 649                         entry->rule.buflen += f->val;
 650                         entry->rule.filterkey = str;
 651                         break;
 652                 case AUDIT_PERM:
 653                         if (f->val & ~15)
 654                                 goto exit_free;
 655                         break;
 656                 case AUDIT_FILETYPE:
 657                         if ((f->val & ~S_IFMT) > S_IFMT)
 658                                 goto exit_free;
 659                         break;
 660                 default:
 661                         goto exit_free;
 662                 }
 663         }
 664
 665         ino_f = entry->rule.inode_f;
 666         if (ino_f) {
 667                 switch(ino_f->op) {
 668                 case AUDIT_NOT_EQUAL:
 669                         entry->rule.inode_f = NULL;
 670                 case AUDIT_EQUAL:
 671                         break;
 672                 default:
 673                         err = -EINVAL;
 674                         goto exit_free;
 675                 }
 676         }
 677
 678 exit_nofree:
 679         return entry;
 680
 681 exit_free:
 682         audit_free_rule(entry);
 683         return ERR_PTR(err);
 684 }
 685
 686 /* Pack a filter field's string representation into data block. */
 687 static inline size_t audit_pack_string(void **bufp, const char *str)
 688 {
 689         size_t len = strlen(str);
 690
 691         memcpy(*bufp, str, len);
 692         *bufp += len;
 693
 694         return len;
 695 }
 696
 697 /* Translate kernel rule respresentation to struct audit_rule.
 698  * Exists for backward compatibility with userspace. */
 699 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
 700 {
 701         struct audit_rule *rule;
 702         int i;
 703
 704         rule = kzalloc(sizeof(*rule), GFP_KERNEL);
 705         if (unlikely(!rule))
 706                 return NULL;
 707
 708         rule->flags = krule->flags | krule->listnr;
 709         rule->action = krule->action;
 710         rule->field_count = krule->field_count;
 711         for (i = 0; i < rule->field_count; i++) {
 712                 rule->values[i] = krule->fields[i].val;
 713                 rule->fields[i] = krule->fields[i].type;
 714
 715                 if (krule->vers_ops == 1) {
 716                         if (krule->fields[i].op & AUDIT_NOT_EQUAL)
 717                                 rule->fields[i] |= AUDIT_NEGATE;
 718                 } else {
 719                         rule->fields[i] |= krule->fields[i].op;
 720                 }
 721         }
 722         for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
 723
 724         return rule;
 725 }
 726
 727 /* Translate kernel rule respresentation to struct audit_rule_data. */
 728 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
 729 {
 730         struct audit_rule_data *data;
 731         void *bufp;
 732         int i;
 733
 734         data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
 735         if (unlikely(!data))
 736                 return NULL;
 737         memset(data, 0, sizeof(*data));
 738
 739         data->flags = krule->flags | krule->listnr;
 740         data->action = krule->action;
 741         data->field_count = krule->field_count;
 742         bufp = data->buf;
 743         for (i = 0; i < data->field_count; i++) {
 744                 struct audit_field *f = &krule->fields[i];
 745
 746                 data->fields[i] = f->type;
 747                 data->fieldflags[i] = f->op;
 748                 switch(f->type) {
 749                 case AUDIT_SUBJ_USER:
 750                 case AUDIT_SUBJ_ROLE:
 751                 case AUDIT_SUBJ_TYPE:
 752                 case AUDIT_SUBJ_SEN:
 753                 case AUDIT_SUBJ_CLR:
 754                 case AUDIT_OBJ_USER:
 755                 case AUDIT_OBJ_ROLE:
 756                 case AUDIT_OBJ_TYPE:
 757                 case AUDIT_OBJ_LEV_LOW:
 758                 case AUDIT_OBJ_LEV_HIGH:
 759                         data->buflen += data->values[i] =
 760                                 audit_pack_string(&bufp, f->lsm_str);
 761                         break;
 762                 case AUDIT_WATCH:
 763                         data->buflen += data->values[i] =
 764                                 audit_pack_string(&bufp, krule->watch->path);
 765                         break;
 766                 case AUDIT_DIR:
 767                         data->buflen += data->values[i] =
 768                                 audit_pack_string(&bufp,
 769                                                   audit_tree_path(krule->tree));
 770                         break;
 771                 case AUDIT_FILTERKEY:
 772                         data->buflen += data->values[i] =
 773                                 audit_pack_string(&bufp, krule->filterkey);
 774                         break;
 775                 default:
 776                         data->values[i] = f->val;
 777                 }
 778         }
 779         for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
 780
 781         return data;
 782 }
 783
 784 /* Compare two rules in kernel format.  Considered success if rules
 785  * don't match. */
 786 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
 787 {
 788         int i;
 789
 790         if (a->flags != b->flags ||
 791             a->listnr != b->listnr ||
 792             a->action != b->action ||
 793             a->field_count != b->field_count)
 794                 return 1;
 795
 796         for (i = 0; i < a->field_count; i++) {
 797                 if (a->fields[i].type != b->fields[i].type ||
 798                     a->fields[i].op != b->fields[i].op)
 799                         return 1;
 800
 801                 switch(a->fields[i].type) {
 802                 case AUDIT_SUBJ_USER:
 803                 case AUDIT_SUBJ_ROLE:
 804                 case AUDIT_SUBJ_TYPE:
 805                 case AUDIT_SUBJ_SEN:
 806                 case AUDIT_SUBJ_CLR:
 807                 case AUDIT_OBJ_USER:
 808                 case AUDIT_OBJ_ROLE:
 809                 case AUDIT_OBJ_TYPE:
 810                 case AUDIT_OBJ_LEV_LOW:
 811                 case AUDIT_OBJ_LEV_HIGH:
 812                         if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
 813                                 return 1;
 814                         break;
 815                 case AUDIT_WATCH:
 816                         if (strcmp(a->watch->path, b->watch->path))
 817                                 return 1;
 818                         break;
 819                 case AUDIT_DIR:
 820                         if (strcmp(audit_tree_path(a->tree),
 821                                    audit_tree_path(b->tree)))
 822                                 return 1;
 823                         break;
 824                 case AUDIT_FILTERKEY:
 825                         /* both filterkeys exist based on above type compare */
 826                         if (strcmp(a->filterkey, b->filterkey))
 827                                 return 1;
 828                         break;
 829                 default:
 830                         if (a->fields[i].val != b->fields[i].val)
 831                                 return 1;
 832                 }
 833         }
 834
 835         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 836                 if (a->mask[i] != b->mask[i])
 837                         return 1;
 838
 839         return 0;
 840 }
 841
 842 /* Duplicate the given audit watch.  The new watch's rules list is initialized
 843  * to an empty list and wlist is undefined. */
 844 static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
 845 {
 846         char *path;
 847         struct audit_watch *new;
 848
 849         path = kstrdup(old->path, GFP_KERNEL);
 850         if (unlikely(!path))
 851                 return ERR_PTR(-ENOMEM);
 852
 853         new = audit_init_watch(path);
 854         if (IS_ERR(new)) {
 855                 kfree(path);
 856                 goto out;
 857         }
 858
 859         new->dev = old->dev;
 860         new->ino = old->ino;
 861         get_inotify_watch(&old->parent->wdata);
 862         new->parent = old->parent;
 863
 864 out:
 865         return new;
 866 }
 867
 868 /* Duplicate LSM field information.  The lsm_rule is opaque, so must be
 869  * re-initialized. */
 870 static inline int audit_dupe_lsm_field(struct audit_field *df,
 871                                            struct audit_field *sf)
 872 {
 873         int ret = 0;
 874         char *lsm_str;
 875
 876         /* our own copy of lsm_str */
 877         lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
 878         if (unlikely(!lsm_str))
 879                 return -ENOMEM;
 880         df->lsm_str = lsm_str;
 881
 882         /* our own (refreshed) copy of lsm_rule */
 883         ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
 884                                        (void **)&df->lsm_rule);
 885         /* Keep currently invalid fields around in case they
 886          * become valid after a policy reload. */
 887         if (ret == -EINVAL) {
 888                 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
 889                        "invalid\n", df->lsm_str);
 890                 ret = 0;
 891         }
 892
 893         return ret;
 894 }
 895
 896 /* Duplicate an audit rule.  This will be a deep copy with the exception
 897  * of the watch - that pointer is carried over.  The LSM specific fields
 898  * will be updated in the copy.  The point is to be able to replace the old
 899  * rule with the new rule in the filterlist, then free the old rule.
 900  * The rlist element is undefined; list manipulations are handled apart from
 901  * the initial copy. */
 902 static struct audit_entry *audit_dupe_rule(struct audit_krule *old,
 903                                            struct audit_watch *watch)
 904 {
 905         u32 fcount = old->field_count;
 906         struct audit_entry *entry;
 907         struct audit_krule *new;
 908         char *fk;
 909         int i, err = 0;
 910
 911         entry = audit_init_entry(fcount);
 912         if (unlikely(!entry))
 913                 return ERR_PTR(-ENOMEM);
 914
 915         new = &entry->rule;
 916         new->vers_ops = old->vers_ops;
 917         new->flags = old->flags;
 918         new->listnr = old->listnr;
 919         new->action = old->action;
 920         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 921                 new->mask[i] = old->mask[i];
 922         new->prio = old->prio;
 923         new->buflen = old->buflen;
 924         new->inode_f = old->inode_f;
 925         new->watch = NULL;
 926         new->field_count = old->field_count;
 927         /*
 928          * note that we are OK with not refcounting here; audit_match_tree()
 929          * never dereferences tree and we can't get false positives there
 930          * since we'd have to have rule gone from the list *and* removed
 931          * before the chunks found by lookup had been allocated, i.e. before
 932          * the beginning of list scan.
 933          */
 934         new->tree = old->tree;
 935         memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
 936
 937         /* deep copy this information, updating the lsm_rule fields, because
 938          * the originals will all be freed when the old rule is freed. */
 939         for (i = 0; i < fcount; i++) {
 940                 switch (new->fields[i].type) {
 941                 case AUDIT_SUBJ_USER:
 942                 case AUDIT_SUBJ_ROLE:
 943                 case AUDIT_SUBJ_TYPE:
 944                 case AUDIT_SUBJ_SEN:
 945                 case AUDIT_SUBJ_CLR:
 946                 case AUDIT_OBJ_USER:
 947                 case AUDIT_OBJ_ROLE:
 948                 case AUDIT_OBJ_TYPE:
 949                 case AUDIT_OBJ_LEV_LOW:
 950                 case AUDIT_OBJ_LEV_HIGH:
 951                         err = audit_dupe_lsm_field(&new->fields[i],
 952                                                        &old->fields[i]);
 953                         break;
 954                 case AUDIT_FILTERKEY:
 955                         fk = kstrdup(old->filterkey, GFP_KERNEL);
 956                         if (unlikely(!fk))
 957                                 err = -ENOMEM;
 958                         else
 959                                 new->filterkey = fk;
 960                 }
 961                 if (err) {
 962                         audit_free_rule(entry);
 963                         return ERR_PTR(err);
 964                 }
 965         }
 966
 967         if (watch) {
 968                 audit_get_watch(watch);
 969                 new->watch = watch;
 970         }
 971
 972         return entry;
 973 }
 974
 975 /* Update inode info in audit rules based on filesystem event. */
 976 static void audit_update_watch(struct audit_parent *parent,
 977                                const char *dname, dev_t dev,
 978                                unsigned long ino, unsigned invalidating)
 979 {
 980         struct audit_watch *owatch, *nwatch, *nextw;
 981         struct audit_krule *r, *nextr;
 982         struct audit_entry *oentry, *nentry;
 983
 984         mutex_lock(&audit_filter_mutex);
 985         list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
 986                 if (audit_compare_dname_path(dname, owatch->path, NULL))
 987                         continue;
 988
 989                 /* If the update involves invalidating rules, do the inode-based
 990                  * filtering now, so we don't omit records. */
 991                 if (invalidating && current->audit_context)
 992                         audit_filter_inodes(current, current->audit_context);
 993
 994                 nwatch = audit_dupe_watch(owatch);
 995                 if (IS_ERR(nwatch)) {
 996                         mutex_unlock(&audit_filter_mutex);
 997                         audit_panic("error updating watch, skipping");
 998                         return;
 999                 }
1000                 nwatch->dev = dev;
1001                 nwatch->ino = ino;
1002
1003                 list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
1004
1005                         oentry = container_of(r, struct audit_entry, rule);
1006                         list_del(&oentry->rule.rlist);
1007                         list_del_rcu(&oentry->list);
1008
1009                         nentry = audit_dupe_rule(&oentry->rule, nwatch);
1010                         if (IS_ERR(nentry))
1011                                 audit_panic("error updating watch, removing");
1012                         else {
1013                                 int h = audit_hash_ino((u32)ino);
1014                                 list_add(&nentry->rule.rlist, &nwatch->rules);
1015                                 list_add_rcu(&nentry->list, &audit_inode_hash[h]);
1016                         }
1017
1018                         call_rcu(&oentry->rcu, audit_free_rule_rcu);
1019                 }
1020
1021                 if (audit_enabled) {
1022                         struct audit_buffer *ab;
1023                         ab = audit_log_start(NULL, GFP_KERNEL,
1024                                 AUDIT_CONFIG_CHANGE);
1025                         audit_log_format(ab, "auid=%u ses=%u",
1026                                 audit_get_loginuid(current),
1027                                 audit_get_sessionid(current));
1028                         audit_log_format(ab,
1029                                 " op=updated rules specifying path=");
1030                         audit_log_untrustedstring(ab, owatch->path);
1031                         audit_log_format(ab, " with dev=%u ino=%lu\n",
1032                                  dev, ino);
1033                         audit_log_format(ab, " list=%d res=1", r->listnr);
1034                         audit_log_end(ab);
1035                 }
1036                 audit_remove_watch(owatch);
1037                 goto add_watch_to_parent; /* event applies to a single watch */
1038         }
1039         mutex_unlock(&audit_filter_mutex);
1040         return;
1041
1042 add_watch_to_parent:
1043         list_add(&nwatch->wlist, &parent->watches);
1044         mutex_unlock(&audit_filter_mutex);
1045         return;
1046 }
1047
1048 /* Remove all watches & rules associated with a parent that is going away. */
1049 static void audit_remove_parent_watches(struct audit_parent *parent)
1050 {
1051         struct audit_watch *w, *nextw;
1052         struct audit_krule *r, *nextr;
1053         struct audit_entry *e;
1054
1055         mutex_lock(&audit_filter_mutex);
1056         parent->flags |= AUDIT_PARENT_INVALID;
1057         list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
1058                 list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
1059                         e = container_of(r, struct audit_entry, rule);
1060                         if (audit_enabled) {
1061                                 struct audit_buffer *ab;
1062                                 ab = audit_log_start(NULL, GFP_KERNEL,
1063                                         AUDIT_CONFIG_CHANGE);
1064                                 audit_log_format(ab, "auid=%u ses=%u",
1065                                         audit_get_loginuid(current),
1066                                         audit_get_sessionid(current));
1067                                 audit_log_format(ab, " op=remove rule path=");
1068                                 audit_log_untrustedstring(ab, w->path);
1069                                 if (r->filterkey) {
1070                                         audit_log_format(ab, " key=");
1071                                         audit_log_untrustedstring(ab,
1072                                                         r->filterkey);
1073                                 } else
1074                                         audit_log_format(ab, " key=(null)");
1075                                 audit_log_format(ab, " list=%d res=1",
1076                                         r->listnr);
1077                                 audit_log_end(ab);
1078                         }
1079                         list_del(&r->rlist);
1080                         list_del_rcu(&e->list);
1081                         call_rcu(&e->rcu, audit_free_rule_rcu);
1082                 }
1083                 audit_remove_watch(w);
1084         }
1085         mutex_unlock(&audit_filter_mutex);
1086 }
1087
1088 /* Unregister inotify watches for parents on in_list.
1089  * Generates an IN_IGNORED event. */
1090 static void audit_inotify_unregister(struct list_head *in_list)
1091 {
1092         struct audit_parent *p, *n;
1093
1094         list_for_each_entry_safe(p, n, in_list, ilist) {
1095                 list_del(&p->ilist);
1096                 inotify_rm_watch(audit_ih, &p->wdata);
1097                 /* the unpin matching the pin in audit_do_del_rule() */
1098                 unpin_inotify_watch(&p->wdata);
1099         }
1100 }
1101
1102 /* Find an existing audit rule.
1103  * Caller must hold audit_filter_mutex to prevent stale rule data. */
1104 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
1105                                            struct list_head *list)
1106 {
1107         struct audit_entry *e, *found = NULL;
1108         int h;
1109
1110         if (entry->rule.watch) {
1111                 /* we don't know the inode number, so must walk entire hash */
1112                 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
1113                         list = &audit_inode_hash[h];
1114                         list_for_each_entry(e, list, list)
1115                                 if (!audit_compare_rule(&entry->rule, &e->rule)) {
1116                                         found = e;
1117                                         goto out;
1118                                 }
1119                 }
1120                 goto out;
1121         }
1122
1123         list_for_each_entry(e, list, list)
1124                 if (!audit_compare_rule(&entry->rule, &e->rule)) {
1125                         found = e;
1126                         goto out;
1127                 }
1128
1129 out:
1130         return found;
1131 }
1132
1133 /* Get path information necessary for adding watches. */
1134 static int audit_get_nd(char *path, struct nameidata **ndp,
1135                         struct nameidata **ndw)
1136 {
1137         struct nameidata *ndparent, *ndwatch;
1138         int err;
1139
1140         ndparent = kmalloc(sizeof(*ndparent), GFP_KERNEL);
1141         if (unlikely(!ndparent))
1142                 return -ENOMEM;
1143
1144         ndwatch = kmalloc(sizeof(*ndwatch), GFP_KERNEL);
1145         if (unlikely(!ndwatch)) {
1146                 kfree(ndparent);
1147                 return -ENOMEM;
1148         }
1149
1150         err = path_lookup(path, LOOKUP_PARENT, ndparent);
1151         if (err) {
1152                 kfree(ndparent);
1153                 kfree(ndwatch);
1154                 return err;
1155         }
1156
1157         err = path_lookup(path, 0, ndwatch);
1158         if (err) {
1159                 kfree(ndwatch);
1160                 ndwatch = NULL;
1161         }
1162
1163         *ndp = ndparent;
1164         *ndw = ndwatch;
1165
1166         return 0;
1167 }
1168
1169 /* Release resources used for watch path information. */
1170 static void audit_put_nd(struct nameidata *ndp, struct nameidata *ndw)
1171 {
1172         if (ndp) {
1173                 path_put(&ndp->path);
1174                 kfree(ndp);
1175         }
1176         if (ndw) {
1177                 path_put(&ndw->path);
1178                 kfree(ndw);
1179         }
1180 }
1181
1182 /* Associate the given rule with an existing parent inotify_watch.
1183  * Caller must hold audit_filter_mutex. */
1184 static void audit_add_to_parent(struct audit_krule *krule,
1185                                 struct audit_parent *parent)
1186 {
1187         struct audit_watch *w, *watch = krule->watch;
1188         int watch_found = 0;
1189
1190         list_for_each_entry(w, &parent->watches, wlist) {
1191                 if (strcmp(watch->path, w->path))
1192                         continue;
1193
1194                 watch_found = 1;
1195
1196                 /* put krule's and initial refs to temporary watch */
1197                 audit_put_watch(watch);
1198                 audit_put_watch(watch);
1199
1200                 audit_get_watch(w);
1201                 krule->watch = watch = w;
1202                 break;
1203         }
1204
1205         if (!watch_found) {
1206                 get_inotify_watch(&parent->wdata);
1207                 watch->parent = parent;
1208
1209                 list_add(&watch->wlist, &parent->watches);
1210         }
1211         list_add(&krule->rlist, &watch->rules);
1212 }
1213
1214 /* Find a matching watch entry, or add this one.
1215  * Caller must hold audit_filter_mutex. */
1216 static int audit_add_watch(struct audit_krule *krule, struct nameidata *ndp,
1217                            struct nameidata *ndw)
1218 {
1219         struct audit_watch *watch = krule->watch;
1220         struct inotify_watch *i_watch;
1221         struct audit_parent *parent;
1222         int ret = 0;
1223
1224         /* update watch filter fields */
1225         if (ndw) {
1226                 watch->dev = ndw->path.dentry->d_inode->i_sb->s_dev;
1227                 watch->ino = ndw->path.dentry->d_inode->i_ino;
1228         }
1229
1230         /* The audit_filter_mutex must not be held during inotify calls because
1231          * we hold it during inotify event callback processing.  If an existing
1232          * inotify watch is found, inotify_find_watch() grabs a reference before
1233          * returning.
1234          */
1235         mutex_unlock(&audit_filter_mutex);
1236
1237         if (inotify_find_watch(audit_ih, ndp->path.dentry->d_inode,
1238                                &i_watch) < 0) {
1239                 parent = audit_init_parent(ndp);
1240                 if (IS_ERR(parent)) {
1241                         /* caller expects mutex locked */
1242                         mutex_lock(&audit_filter_mutex);
1243                         return PTR_ERR(parent);
1244                 }
1245         } else
1246                 parent = container_of(i_watch, struct audit_parent, wdata);
1247
1248         mutex_lock(&audit_filter_mutex);
1249
1250         /* parent was moved before we took audit_filter_mutex */
1251         if (parent->flags & AUDIT_PARENT_INVALID)
1252                 ret = -ENOENT;
1253         else
1254                 audit_add_to_parent(krule, parent);
1255
1256         /* match get in audit_init_parent or inotify_find_watch */
1257         put_inotify_watch(&parent->wdata);
1258         return ret;
1259 }
1260
1261 static u64 prio_low = ~0ULL/2;
1262 static u64 prio_high = ~0ULL/2 - 1;
1263
1264 /* Add rule to given filterlist if not a duplicate. */
1265 static inline int audit_add_rule(struct audit_entry *entry,
1266                                  struct list_head *list)
1267 {
1268         struct audit_entry *e;
1269         struct audit_field *inode_f = entry->rule.inode_f;
1270         struct audit_watch *watch = entry->rule.watch;
1271         struct audit_tree *tree = entry->rule.tree;
1272         struct nameidata *ndp = NULL, *ndw = NULL;
1273         int h, err;
1274 #ifdef CONFIG_AUDITSYSCALL
1275         int dont_count = 0;
1276
1277         /* If either of these, don't count towards total */
1278         if (entry->rule.listnr == AUDIT_FILTER_USER ||
1279                 entry->rule.listnr == AUDIT_FILTER_TYPE)
1280                 dont_count = 1;
1281 #endif
1282
1283         if (inode_f) {
1284                 h = audit_hash_ino(inode_f->val);
1285                 list = &audit_inode_hash[h];
1286         }
1287
1288         mutex_lock(&audit_filter_mutex);
1289         e = audit_find_rule(entry, list);
1290         mutex_unlock(&audit_filter_mutex);
1291         if (e) {
1292                 err = -EEXIST;
1293                 /* normally audit_add_tree_rule() will free it on failure */
1294                 if (tree)
1295                         audit_put_tree(tree);
1296                 goto error;
1297         }
1298
1299         /* Avoid calling path_lookup under audit_filter_mutex. */
1300         if (watch) {
1301                 err = audit_get_nd(watch->path, &ndp, &ndw);
1302                 if (err)
1303                         goto error;
1304         }
1305
1306         mutex_lock(&audit_filter_mutex);
1307         if (watch) {
1308                 /* audit_filter_mutex is dropped and re-taken during this call */
1309                 err = audit_add_watch(&entry->rule, ndp, ndw);
1310                 if (err) {
1311                         mutex_unlock(&audit_filter_mutex);
1312                         goto error;
1313                 }
1314                 h = audit_hash_ino((u32)watch->ino);
1315                 list = &audit_inode_hash[h];
1316         }
1317         if (tree) {
1318                 err = audit_add_tree_rule(&entry->rule);
1319                 if (err) {
1320                         mutex_unlock(&audit_filter_mutex);
1321                         goto error;
1322                 }
1323         }
1324
1325         entry->rule.prio = ~0ULL;
1326         if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
1327                 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
1328                         entry->rule.prio = ++prio_high;
1329                 else
1330                         entry->rule.prio = --prio_low;
1331         }
1332
1333         if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
1334                 list_add_rcu(&entry->list, list);
1335                 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
1336         } else {
1337                 list_add_tail_rcu(&entry->list, list);
1338         }
1339 #ifdef CONFIG_AUDITSYSCALL
1340         if (!dont_count)
1341                 audit_n_rules++;
1342
1343         if (!audit_match_signal(entry))
1344                 audit_signals++;
1345 #endif
1346         mutex_unlock(&audit_filter_mutex);
1347
1348         audit_put_nd(ndp, ndw);         /* NULL args OK */
1349         return 0;
1350
1351 error:
1352         audit_put_nd(ndp, ndw);         /* NULL args OK */
1353         if (watch)
1354                 audit_put_watch(watch); /* tmp watch, matches initial get */
1355         return err;
1356 }
1357
1358 /* Remove an existing rule from filterlist. */
1359 static inline int audit_del_rule(struct audit_entry *entry,
1360                                  struct list_head *list)
1361 {
1362         struct audit_entry  *e;
1363         struct audit_field *inode_f = entry->rule.inode_f;
1364         struct audit_watch *watch, *tmp_watch = entry->rule.watch;
1365         struct audit_tree *tree = entry->rule.tree;
1366         LIST_HEAD(inotify_list);
1367         int h, ret = 0;
1368 #ifdef CONFIG_AUDITSYSCALL
1369         int dont_count = 0;
1370
1371         /* If either of these, don't count towards total */
1372         if (entry->rule.listnr == AUDIT_FILTER_USER ||
1373                 entry->rule.listnr == AUDIT_FILTER_TYPE)
1374                 dont_count = 1;
1375 #endif
1376
1377         if (inode_f) {
1378                 h = audit_hash_ino(inode_f->val);
1379                 list = &audit_inode_hash[h];
1380         }
1381
1382         mutex_lock(&audit_filter_mutex);
1383         e = audit_find_rule(entry, list);
1384         if (!e) {
1385                 mutex_unlock(&audit_filter_mutex);
1386                 ret = -ENOENT;
1387                 goto out;
1388         }
1389
1390         watch = e->rule.watch;
1391         if (watch) {
1392                 struct audit_parent *parent = watch->parent;
1393
1394                 list_del(&e->rule.rlist);
1395
1396                 if (list_empty(&watch->rules)) {
1397                         audit_remove_watch(watch);
1398
1399                         if (list_empty(&parent->watches)) {
1400                                 /* Put parent on the inotify un-registration
1401                                  * list.  Grab a reference before releasing
1402                                  * audit_filter_mutex, to be released in
1403                                  * audit_inotify_unregister().
1404                                  * If filesystem is going away, just leave
1405                                  * the sucker alone, eviction will take
1406                                  * care of it.
1407                                  */
1408                                 if (pin_inotify_watch(&parent->wdata))
1409                                         list_add(&parent->ilist, &inotify_list);
1410                         }
1411                 }
1412         }
1413
1414         if (e->rule.tree)
1415                 audit_remove_tree_rule(&e->rule);
1416
1417         list_del_rcu(&e->list);
1418         call_rcu(&e->rcu, audit_free_rule_rcu);
1419
1420 #ifdef CONFIG_AUDITSYSCALL
1421         if (!dont_count)
1422                 audit_n_rules--;
1423
1424         if (!audit_match_signal(entry))
1425                 audit_signals--;
1426 #endif
1427         mutex_unlock(&audit_filter_mutex);
1428
1429         if (!list_empty(&inotify_list))
1430                 audit_inotify_unregister(&inotify_list);
1431
1432 out:
1433         if (tmp_watch)
1434                 audit_put_watch(tmp_watch); /* match initial get */
1435         if (tree)
1436                 audit_put_tree(tree);   /* that's the temporary one */
1437
1438         return ret;
1439 }
1440
1441 /* List rules using struct audit_rule.  Exists for backward
1442  * compatibility with userspace. */
1443 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1444 {
1445         struct sk_buff *skb;
1446         struct audit_entry *entry;
1447         int i;
1448
1449         /* This is a blocking read, so use audit_filter_mutex instead of rcu
1450          * iterator to sync with list writers. */
1451         for (i=0; i<AUDIT_NR_FILTERS; i++) {
1452                 list_for_each_entry(entry, &audit_filter_list[i], list) {
1453                         struct audit_rule *rule;
1454
1455                         rule = audit_krule_to_rule(&entry->rule);
1456                         if (unlikely(!rule))
1457                                 break;
1458                         skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1459                                          rule, sizeof(*rule));
1460                         if (skb)
1461                                 skb_queue_tail(q, skb);
1462                         kfree(rule);
1463                 }
1464         }
1465         for (i = 0; i < AUDIT_INODE_BUCKETS; i++) {
1466                 list_for_each_entry(entry, &audit_inode_hash[i], list) {
1467                         struct audit_rule *rule;
1468
1469                         rule = audit_krule_to_rule(&entry->rule);
1470                         if (unlikely(!rule))
1471                                 break;
1472                         skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1473                                          rule, sizeof(*rule));
1474                         if (skb)
1475                                 skb_queue_tail(q, skb);
1476                         kfree(rule);
1477                 }
1478         }
1479         skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1480         if (skb)
1481                 skb_queue_tail(q, skb);
1482 }
1483
1484 /* List rules using struct audit_rule_data. */
1485 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1486 {
1487         struct sk_buff *skb;
1488         struct audit_entry *e;
1489         int i;
1490
1491         /* This is a blocking read, so use audit_filter_mutex instead of rcu
1492          * iterator to sync with list writers. */
1493         for (i=0; i<AUDIT_NR_FILTERS; i++) {
1494                 list_for_each_entry(e, &audit_filter_list[i], list) {
1495                         struct audit_rule_data *data;
1496
1497                         data = audit_krule_to_data(&e->rule);
1498                         if (unlikely(!data))
1499                                 break;
1500                         skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1501                                          data, sizeof(*data) + data->buflen);
1502                         if (skb)
1503                                 skb_queue_tail(q, skb);
1504                         kfree(data);
1505                 }
1506         }
1507         for (i=0; i< AUDIT_INODE_BUCKETS; i++) {
1508                 list_for_each_entry(e, &audit_inode_hash[i], list) {
1509                         struct audit_rule_data *data;
1510
1511                         data = audit_krule_to_data(&e->rule);
1512                         if (unlikely(!data))
1513                                 break;
1514                         skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1515                                          data, sizeof(*data) + data->buflen);
1516                         if (skb)
1517                                 skb_queue_tail(q, skb);
1518                         kfree(data);
1519                 }
1520         }
1521         skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1522         if (skb)
1523                 skb_queue_tail(q, skb);
1524 }
1525
1526 /* Log rule additions and removals */
1527 static void audit_log_rule_change(uid_t loginuid, u32 sessionid, u32 sid,
1528                                   char *action, struct audit_krule *rule,
1529                                   int res)
1530 {
1531         struct audit_buffer *ab;
1532
1533         if (!audit_enabled)
1534                 return;
1535
1536         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1537         if (!ab)
1538                 return;
1539         audit_log_format(ab, "auid=%u ses=%u", loginuid, sessionid);
1540         if (sid) {
1541                 char *ctx = NULL;
1542                 u32 len;
1543                 if (security_secid_to_secctx(sid, &ctx, &len))
1544                         audit_log_format(ab, " ssid=%u", sid);
1545                 else {
1546                         audit_log_format(ab, " subj=%s", ctx);
1547                         security_release_secctx(ctx, len);
1548                 }
1549         }
1550         audit_log_format(ab, " op=%s rule key=", action);
1551         if (rule->filterkey)
1552                 audit_log_untrustedstring(ab, rule->filterkey);
1553         else
1554                 audit_log_format(ab, "(null)");
1555         audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1556         audit_log_end(ab);
1557 }
1558
1559 /**
1560  * audit_receive_filter - apply all rules to the specified message type
1561  * @type: audit message type
1562  * @pid: target pid for netlink audit messages
1563  * @uid: target uid for netlink audit messages
1564  * @seq: netlink audit message sequence (serial) number
1565  * @data: payload data
1566  * @datasz: size of payload data
1567  * @loginuid: loginuid of sender
1568  * @sessionid: sessionid for netlink audit message
1569  * @sid: SE Linux Security ID of sender
1570  */
1571 int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1572                          size_t datasz, uid_t loginuid, u32 sessionid, u32 sid)
1573 {
1574         struct task_struct *tsk;
1575         struct audit_netlink_list *dest;
1576         int err = 0;
1577         struct audit_entry *entry;
1578
1579         switch (type) {
1580         case AUDIT_LIST:
1581         case AUDIT_LIST_RULES:
1582                 /* We can't just spew out the rules here because we might fill
1583                  * the available socket buffer space and deadlock waiting for
1584                  * auditctl to read from it... which isn't ever going to
1585                  * happen if we're actually running in the context of auditctl
1586                  * trying to _send_ the stuff */
1587
1588                 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1589                 if (!dest)
1590                         return -ENOMEM;
1591                 dest->pid = pid;
1592                 skb_queue_head_init(&dest->q);
1593
1594                 mutex_lock(&audit_filter_mutex);
1595                 if (type == AUDIT_LIST)
1596                         audit_list(pid, seq, &dest->q);
1597                 else
1598                         audit_list_rules(pid, seq, &dest->q);
1599                 mutex_unlock(&audit_filter_mutex);
1600
1601                 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1602                 if (IS_ERR(tsk)) {
1603                         skb_queue_purge(&dest->q);
1604                         kfree(dest);
1605                         err = PTR_ERR(tsk);
1606                 }
1607                 break;
1608         case AUDIT_ADD:
1609         case AUDIT_ADD_RULE:
1610                 if (type == AUDIT_ADD)
1611                         entry = audit_rule_to_entry(data);
1612                 else
1613                         entry = audit_data_to_entry(data, datasz);
1614                 if (IS_ERR(entry))
1615                         return PTR_ERR(entry);
1616
1617                 err = audit_add_rule(entry,
1618                                      &audit_filter_list[entry->rule.listnr]);
1619                 audit_log_rule_change(loginuid, sessionid, sid, "add",
1620                                       &entry->rule, !err);
1621
1622                 if (err)
1623                         audit_free_rule(entry);
1624                 break;
1625         case AUDIT_DEL:
1626         case AUDIT_DEL_RULE:
1627                 if (type == AUDIT_DEL)
1628                         entry = audit_rule_to_entry(data);
1629                 else
1630                         entry = audit_data_to_entry(data, datasz);
1631                 if (IS_ERR(entry))
1632                         return PTR_ERR(entry);
1633
1634                 err = audit_del_rule(entry,
1635                                      &audit_filter_list[entry->rule.listnr]);
1636                 audit_log_rule_change(loginuid, sessionid, sid, "remove",
1637                                       &entry->rule, !err);
1638
1639                 audit_free_rule(entry);
1640                 break;
1641         default:
1642                 return -EINVAL;
1643         }
1644
1645         return err;
1646 }
1647
1648 int audit_comparator(const u32 left, const u32 op, const u32 right)
1649 {
1650         switch (op) {
1651         case AUDIT_EQUAL:
1652                 return (left == right);
1653         case AUDIT_NOT_EQUAL:
1654                 return (left != right);
1655         case AUDIT_LESS_THAN:
1656                 return (left < right);
1657         case AUDIT_LESS_THAN_OR_EQUAL:
1658                 return (left <= right);
1659         case AUDIT_GREATER_THAN:
1660                 return (left > right);
1661         case AUDIT_GREATER_THAN_OR_EQUAL:
1662                 return (left >= right);
1663         case AUDIT_BIT_MASK:
1664                 return (left & right);
1665         case AUDIT_BIT_TEST:
1666                 return ((left & right) == right);
1667         }
1668         BUG();
1669         return 0;
1670 }
1671
1672 /* Compare given dentry name with last component in given path,
1673  * return of 0 indicates a match. */
1674 int audit_compare_dname_path(const char *dname, const char *path,
1675                              int *dirlen)
1676 {
1677         int dlen, plen;
1678         const char *p;
1679
1680         if (!dname || !path)
1681                 return 1;
1682
1683         dlen = strlen(dname);
1684         plen = strlen(path);
1685         if (plen < dlen)
1686                 return 1;
1687
1688         /* disregard trailing slashes */
1689         p = path + plen - 1;
1690         while ((*p == '/') && (p > path))
1691                 p--;
1692
1693         /* find last path component */
1694         p = p - dlen + 1;
1695         if (p < path)
1696                 return 1;
1697         else if (p > path) {
1698                 if (*--p != '/')
1699                         return 1;
1700                 else
1701                         p++;
1702         }
1703
1704         /* return length of path's directory component */
1705         if (dirlen)
1706                 *dirlen = p - path;
1707         return strncmp(p, dname, dlen);
1708 }
1709
1710 static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1711                                    struct audit_krule *rule,
1712                                    enum audit_state *state)
1713 {
1714         int i;
1715
1716         for (i = 0; i < rule->field_count; i++) {
1717                 struct audit_field *f = &rule->fields[i];
1718                 int result = 0;
1719
1720                 switch (f->type) {
1721                 case AUDIT_PID:
1722                         result = audit_comparator(cb->creds.pid, f->op, f->val);
1723                         break;
1724                 case AUDIT_UID:
1725                         result = audit_comparator(cb->creds.uid, f->op, f->val);
1726                         break;
1727                 case AUDIT_GID:
1728                         result = audit_comparator(cb->creds.gid, f->op, f->val);
1729                         break;
1730                 case AUDIT_LOGINUID:
1731                         result = audit_comparator(cb->loginuid, f->op, f->val);
1732                         break;
1733                 }
1734
1735                 if (!result)
1736                         return 0;
1737         }
1738         switch (rule->action) {
1739         case AUDIT_NEVER:    *state = AUDIT_DISABLED;       break;
1740         case AUDIT_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
1741         }
1742         return 1;
1743 }
1744
1745 int audit_filter_user(struct netlink_skb_parms *cb)
1746 {
1747         enum audit_state state = AUDIT_DISABLED;
1748         struct audit_entry *e;
1749         int ret = 1;
1750
1751         rcu_read_lock();
1752         list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1753                 if (audit_filter_user_rules(cb, &e->rule, &state)) {
1754                         if (state == AUDIT_DISABLED)
1755                                 ret = 0;
1756                         break;
1757                 }
1758         }
1759         rcu_read_unlock();
1760
1761         return ret; /* Audit by default */
1762 }
1763
1764 int audit_filter_type(int type)
1765 {
1766         struct audit_entry *e;
1767         int result = 0;
1768
1769         rcu_read_lock();
1770         if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1771                 goto unlock_and_return;
1772
1773         list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1774                                 list) {
1775                 int i;
1776                 for (i = 0; i < e->rule.field_count; i++) {
1777                         struct audit_field *f = &e->rule.fields[i];
1778                         if (f->type == AUDIT_MSGTYPE) {
1779                                 result = audit_comparator(type, f->op, f->val);
1780                                 if (!result)
1781                                         break;
1782                         }
1783                 }
1784                 if (result)
1785                         goto unlock_and_return;
1786         }
1787 unlock_and_return:
1788         rcu_read_unlock();
1789         return result;
1790 }
1791
1792 static int update_lsm_rule(struct audit_entry *entry)
1793 {
1794         struct audit_entry *nentry;
1795         struct audit_watch *watch;
1796         struct audit_tree *tree;
1797         int err = 0;
1798
1799         if (!security_audit_rule_known(&entry->rule))
1800                 return 0;
1801
1802         watch = entry->rule.watch;
1803         tree = entry->rule.tree;
1804         nentry = audit_dupe_rule(&entry->rule, watch);
1805         if (IS_ERR(nentry)) {
1806                 /* save the first error encountered for the
1807                  * return value */
1808                 err = PTR_ERR(nentry);
1809                 audit_panic("error updating LSM filters");
1810                 if (watch)
1811                         list_del(&entry->rule.rlist);
1812                 list_del_rcu(&entry->list);
1813         } else {
1814                 if (watch) {
1815                         list_add(&nentry->rule.rlist, &watch->rules);
1816                         list_del(&entry->rule.rlist);
1817                 } else if (tree)
1818                         list_replace_init(&entry->rule.rlist,
1819                                      &nentry->rule.rlist);
1820                 list_replace_rcu(&entry->list, &nentry->list);
1821         }
1822         call_rcu(&entry->rcu, audit_free_rule_rcu);
1823
1824         return err;
1825 }
1826
1827 /* This function will re-initialize the lsm_rule field of all applicable rules.
1828  * It will traverse the filter lists serarching for rules that contain LSM
1829  * specific filter fields.  When such a rule is found, it is copied, the
1830  * LSM field is re-initialized, and the old rule is replaced with the
1831  * updated rule. */
1832 int audit_update_lsm_rules(void)
1833 {
1834         struct audit_entry *e, *n;
1835         int i, err = 0;
1836
1837         /* audit_filter_mutex synchronizes the writers */
1838         mutex_lock(&audit_filter_mutex);
1839
1840         for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1841                 list_for_each_entry_safe(e, n, &audit_filter_list[i], list) {
1842                         int res = update_lsm_rule(e);
1843                         if (!err)
1844                                 err = res;
1845                 }
1846         }
1847         for (i=0; i< AUDIT_INODE_BUCKETS; i++) {
1848                 list_for_each_entry_safe(e, n, &audit_inode_hash[i], list) {
1849                         int res = update_lsm_rule(e);
1850                         if (!err)
1851                                 err = res;
1852                 }
1853         }
1854
1855         mutex_unlock(&audit_filter_mutex);
1856
1857         return err;
1858 }
1859
1860 /* Update watch data in audit rules based on inotify events. */
1861 void audit_handle_ievent(struct inotify_watch *i_watch, u32 wd, u32 mask,
1862                          u32 cookie, const char *dname, struct inode *inode)
1863 {
1864         struct audit_parent *parent;
1865
1866         parent = container_of(i_watch, struct audit_parent, wdata);
1867
1868         if (mask & (IN_CREATE|IN_MOVED_TO) && inode)
1869                 audit_update_watch(parent, dname, inode->i_sb->s_dev,
1870                                    inode->i_ino, 0);
1871         else if (mask & (IN_DELETE|IN_MOVED_FROM))
1872                 audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1);
1873         /* inotify automatically removes the watch and sends IN_IGNORED */
1874         else if (mask & (IN_DELETE_SELF|IN_UNMOUNT))
1875                 audit_remove_parent_watches(parent);
1876         /* inotify does not remove the watch, so remove it manually */
1877         else if(mask & IN_MOVE_SELF) {
1878                 audit_remove_parent_watches(parent);
1879                 inotify_remove_watch_locked(audit_ih, i_watch);
1880         } else if (mask & IN_IGNORED)
1881                 put_inotify_watch(i_watch);
1882 }