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