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