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