kernel/auditfilter.c

   1 /* auditfilter.c -- filtering of audit events
   2  *
   3  * Copyright 2003-2004 Red Hat, Inc.
   4  * Copyright 2005 Hewlett-Packard Development Company, L.P.
   5  * Copyright 2005 IBM Corporation
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/audit.h>
  24 #include <linux/kthread.h>
  25 #include <linux/mutex.h>
  26 #include <linux/fs.h>
  27 #include <linux/namei.h>
  28 #include <linux/netlink.h>
  29 #include <linux/sched.h>
  30 #include <linux/slab.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 /* Audit filter lists, defined in <linux/audit.h> */
  48 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
  49         LIST_HEAD_INIT(audit_filter_list[0]),
  50         LIST_HEAD_INIT(audit_filter_list[1]),
  51         LIST_HEAD_INIT(audit_filter_list[2]),
  52         LIST_HEAD_INIT(audit_filter_list[3]),
  53         LIST_HEAD_INIT(audit_filter_list[4]),
  54         LIST_HEAD_INIT(audit_filter_list[5]),
  55 #if AUDIT_NR_FILTERS != 6
  56 #error Fix audit_filter_list initialiser
  57 #endif
  58 };
  59 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
  60         LIST_HEAD_INIT(audit_rules_list[0]),
  61         LIST_HEAD_INIT(audit_rules_list[1]),
  62         LIST_HEAD_INIT(audit_rules_list[2]),
  63         LIST_HEAD_INIT(audit_rules_list[3]),
  64         LIST_HEAD_INIT(audit_rules_list[4]),
  65         LIST_HEAD_INIT(audit_rules_list[5]),
  66 };
  67
  68 DEFINE_MUTEX(audit_filter_mutex);
  69
  70 static inline void audit_free_rule(struct audit_entry *e)
  71 {
  72         int i;
  73         struct audit_krule *erule = &e->rule;
  74
  75         /* some rules don't have associated watches */
  76         if (erule->watch)
  77                 audit_put_watch(erule->watch);
  78         if (erule->fields)
  79                 for (i = 0; i < erule->field_count; i++) {
  80                         struct audit_field *f = &erule->fields[i];
  81                         kfree(f->lsm_str);
  82                         security_audit_rule_free(f->lsm_rule);
  83                 }
  84         kfree(erule->fields);
  85         kfree(erule->filterkey);
  86         kfree(e);
  87 }
  88
  89 void audit_free_rule_rcu(struct rcu_head *head)
  90 {
  91         struct audit_entry *e = container_of(head, struct audit_entry, rcu);
  92         audit_free_rule(e);
  93 }
  94
  95 /* Initialize an audit filterlist entry. */
  96 static inline struct audit_entry *audit_init_entry(u32 field_count)
  97 {
  98         struct audit_entry *entry;
  99         struct audit_field *fields;
 100
 101         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 102         if (unlikely(!entry))
 103                 return NULL;
 104
 105         fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
 106         if (unlikely(!fields)) {
 107                 kfree(entry);
 108                 return NULL;
 109         }
 110         entry->rule.fields = fields;
 111
 112         return entry;
 113 }
 114
 115 /* Unpack a filter field's string representation from user-space
 116  * buffer. */
 117 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
 118 {
 119         char *str;
 120
 121         if (!*bufp || (len == 0) || (len > *remain))
 122                 return ERR_PTR(-EINVAL);
 123
 124         /* Of the currently implemented string fields, PATH_MAX
 125          * defines the longest valid length.
 126          */
 127         if (len > PATH_MAX)
 128                 return ERR_PTR(-ENAMETOOLONG);
 129
 130         str = kmalloc(len + 1, GFP_KERNEL);
 131         if (unlikely(!str))
 132                 return ERR_PTR(-ENOMEM);
 133
 134         memcpy(str, *bufp, len);
 135         str[len] = 0;
 136         *bufp += len;
 137         *remain -= len;
 138
 139         return str;
 140 }
 141
 142 /* Translate an inode field to kernel respresentation. */
 143 static inline int audit_to_inode(struct audit_krule *krule,
 144                                  struct audit_field *f)
 145 {
 146         if (krule->listnr != AUDIT_FILTER_EXIT ||
 147             krule->watch || krule->inode_f || krule->tree ||
 148             (f->op != Audit_equal && f->op != Audit_not_equal))
 149                 return -EINVAL;
 150
 151         krule->inode_f = f;
 152         return 0;
 153 }
 154
 155 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
 156
 157 int __init audit_register_class(int class, unsigned *list)
 158 {
 159         __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
 160         if (!p)
 161                 return -ENOMEM;
 162         while (*list != ~0U) {
 163                 unsigned n = *list++;
 164                 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
 165                         kfree(p);
 166                         return -EINVAL;
 167                 }
 168                 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
 169         }
 170         if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
 171                 kfree(p);
 172                 return -EINVAL;
 173         }
 174         classes[class] = p;
 175         return 0;
 176 }
 177
 178 int audit_match_class(int class, unsigned syscall)
 179 {
 180         if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
 181                 return 0;
 182         if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
 183                 return 0;
 184         return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
 185 }
 186
 187 #ifdef CONFIG_AUDITSYSCALL
 188 static inline int audit_match_class_bits(int class, u32 *mask)
 189 {
 190         int i;
 191
 192         if (classes[class]) {
 193                 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 194                         if (mask[i] & classes[class][i])
 195                                 return 0;
 196         }
 197         return 1;
 198 }
 199
 200 static int audit_match_signal(struct audit_entry *entry)
 201 {
 202         struct audit_field *arch = entry->rule.arch_f;
 203
 204         if (!arch) {
 205                 /* When arch is unspecified, we must check both masks on biarch
 206                  * as syscall number alone is ambiguous. */
 207                 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
 208                                                entry->rule.mask) &&
 209                         audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
 210                                                entry->rule.mask));
 211         }
 212
 213         switch(audit_classify_arch(arch->val)) {
 214         case 0: /* native */
 215                 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
 216                                                entry->rule.mask));
 217         case 1: /* 32bit on biarch */
 218                 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
 219                                                entry->rule.mask));
 220         default:
 221                 return 1;
 222         }
 223 }
 224 #endif
 225
 226 /* Common user-space to kernel rule translation. */
 227 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
 228 {
 229         unsigned listnr;
 230         struct audit_entry *entry;
 231         int i, err;
 232
 233         err = -EINVAL;
 234         listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
 235         switch(listnr) {
 236         default:
 237                 goto exit_err;
 238 #ifdef CONFIG_AUDITSYSCALL
 239         case AUDIT_FILTER_ENTRY:
 240                 if (rule->action == AUDIT_ALWAYS)
 241                         goto exit_err;
 242         case AUDIT_FILTER_EXIT:
 243         case AUDIT_FILTER_TASK:
 244 #endif
 245         case AUDIT_FILTER_USER:
 246         case AUDIT_FILTER_TYPE:
 247                 ;
 248         }
 249         if (unlikely(rule->action == AUDIT_POSSIBLE)) {
 250                 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
 251                 goto exit_err;
 252         }
 253         if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
 254                 goto exit_err;
 255         if (rule->field_count > AUDIT_MAX_FIELDS)
 256                 goto exit_err;
 257
 258         err = -ENOMEM;
 259         entry = audit_init_entry(rule->field_count);
 260         if (!entry)
 261                 goto exit_err;
 262
 263         entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
 264         entry->rule.listnr = listnr;
 265         entry->rule.action = rule->action;
 266         entry->rule.field_count = rule->field_count;
 267
 268         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 269                 entry->rule.mask[i] = rule->mask[i];
 270
 271         for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
 272                 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
 273                 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
 274                 __u32 *class;
 275
 276                 if (!(*p & AUDIT_BIT(bit)))
 277                         continue;
 278                 *p &= ~AUDIT_BIT(bit);
 279                 class = classes[i];
 280                 if (class) {
 281                         int j;
 282                         for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
 283                                 entry->rule.mask[j] |= class[j];
 284                 }
 285         }
 286
 287         return entry;
 288
 289 exit_err:
 290         return ERR_PTR(err);
 291 }
 292
 293 static u32 audit_ops[] =
 294 {
 295         [Audit_equal] = AUDIT_EQUAL,
 296         [Audit_not_equal] = AUDIT_NOT_EQUAL,
 297         [Audit_bitmask] = AUDIT_BIT_MASK,
 298         [Audit_bittest] = AUDIT_BIT_TEST,
 299         [Audit_lt] = AUDIT_LESS_THAN,
 300         [Audit_gt] = AUDIT_GREATER_THAN,
 301         [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
 302         [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
 303 };
 304
 305 static u32 audit_to_op(u32 op)
 306 {
 307         u32 n;
 308         for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
 309                 ;
 310         return n;
 311 }
 312
 313
 314 /* Translate struct audit_rule to kernel's rule respresentation.
 315  * Exists for backward compatibility with userspace. */
 316 static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
 317 {
 318         struct audit_entry *entry;
 319         int err = 0;
 320         int i;
 321
 322         entry = audit_to_entry_common(rule);
 323         if (IS_ERR(entry))
 324                 goto exit_nofree;
 325
 326         for (i = 0; i < rule->field_count; i++) {
 327                 struct audit_field *f = &entry->rule.fields[i];
 328                 u32 n;
 329
 330                 n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
 331
 332                 /* Support for legacy operators where
 333                  * AUDIT_NEGATE bit signifies != and otherwise assumes == */
 334                 if (n & AUDIT_NEGATE)
 335                         f->op = Audit_not_equal;
 336                 else if (!n)
 337                         f->op = Audit_equal;
 338                 else
 339                         f->op = audit_to_op(n);
 340
 341                 entry->rule.vers_ops = (n & AUDIT_OPERATORS) ? 2 : 1;
 342
 343                 f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
 344                 f->val = rule->values[i];
 345
 346                 err = -EINVAL;
 347                 if (f->op == Audit_bad)
 348                         goto exit_free;
 349
 350                 switch(f->type) {
 351                 default:
 352                         goto exit_free;
 353                 case AUDIT_PID:
 354                 case AUDIT_UID:
 355                 case AUDIT_EUID:
 356                 case AUDIT_SUID:
 357                 case AUDIT_FSUID:
 358                 case AUDIT_GID:
 359                 case AUDIT_EGID:
 360                 case AUDIT_SGID:
 361                 case AUDIT_FSGID:
 362                 case AUDIT_LOGINUID:
 363                 case AUDIT_PERS:
 364                 case AUDIT_MSGTYPE:
 365                 case AUDIT_PPID:
 366                 case AUDIT_DEVMAJOR:
 367                 case AUDIT_DEVMINOR:
 368                 case AUDIT_EXIT:
 369                 case AUDIT_SUCCESS:
 370                         /* bit ops are only useful on syscall args */
 371                         if (f->op == Audit_bitmask || f->op == Audit_bittest)
 372                                 goto exit_free;
 373                         break;
 374                 case AUDIT_ARG0:
 375                 case AUDIT_ARG1:
 376                 case AUDIT_ARG2:
 377                 case AUDIT_ARG3:
 378                         break;
 379                 /* arch is only allowed to be = or != */
 380                 case AUDIT_ARCH:
 381                         if (f->op != Audit_not_equal && f->op != Audit_equal)
 382                                 goto exit_free;
 383                         entry->rule.arch_f = f;
 384                         break;
 385                 case AUDIT_PERM:
 386                         if (f->val & ~15)
 387                                 goto exit_free;
 388                         break;
 389                 case AUDIT_FILETYPE:
 390                         if (f->val & ~S_IFMT)
 391                                 goto exit_free;
 392                         break;
 393                 case AUDIT_INODE:
 394                         err = audit_to_inode(&entry->rule, f);
 395                         if (err)
 396                                 goto exit_free;
 397                         break;
 398                 }
 399         }
 400
 401         if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
 402                 entry->rule.inode_f = NULL;
 403
 404 exit_nofree:
 405         return entry;
 406
 407 exit_free:
 408         audit_free_rule(entry);
 409         return ERR_PTR(err);
 410 }
 411
 412 /* Translate struct audit_rule_data to kernel's rule respresentation. */
 413 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
 414                                                size_t datasz)
 415 {
 416         int err = 0;
 417         struct audit_entry *entry;
 418         void *bufp;
 419         size_t remain = datasz - sizeof(struct audit_rule_data);
 420         int i;
 421         char *str;
 422
 423         entry = audit_to_entry_common((struct audit_rule *)data);
 424         if (IS_ERR(entry))
 425                 goto exit_nofree;
 426
 427         bufp = data->buf;
 428         entry->rule.vers_ops = 2;
 429         for (i = 0; i < data->field_count; i++) {
 430                 struct audit_field *f = &entry->rule.fields[i];
 431
 432                 err = -EINVAL;
 433
 434                 f->op = audit_to_op(data->fieldflags[i]);
 435                 if (f->op == Audit_bad)
 436                         goto exit_free;
 437
 438                 f->type = data->fields[i];
 439                 f->val = data->values[i];
 440                 f->lsm_str = NULL;
 441                 f->lsm_rule = NULL;
 442                 switch(f->type) {
 443                 case AUDIT_PID:
 444                 case AUDIT_UID:
 445                 case AUDIT_EUID:
 446                 case AUDIT_SUID:
 447                 case AUDIT_FSUID:
 448                 case AUDIT_GID:
 449                 case AUDIT_EGID:
 450                 case AUDIT_SGID:
 451                 case AUDIT_FSGID:
 452                 case AUDIT_LOGINUID:
 453                 case AUDIT_PERS:
 454                 case AUDIT_MSGTYPE:
 455                 case AUDIT_PPID:
 456                 case AUDIT_DEVMAJOR:
 457                 case AUDIT_DEVMINOR:
 458                 case AUDIT_EXIT:
 459                 case AUDIT_SUCCESS:
 460                 case AUDIT_ARG0:
 461                 case AUDIT_ARG1:
 462                 case AUDIT_ARG2:
 463                 case AUDIT_ARG3:
 464                 case AUDIT_OBJ_UID:
 465                 case AUDIT_OBJ_GID:
 466                         break;
 467                 case AUDIT_ARCH:
 468                         entry->rule.arch_f = f;
 469                         break;
 470                 case AUDIT_SUBJ_USER:
 471                 case AUDIT_SUBJ_ROLE:
 472                 case AUDIT_SUBJ_TYPE:
 473                 case AUDIT_SUBJ_SEN:
 474                 case AUDIT_SUBJ_CLR:
 475                 case AUDIT_OBJ_USER:
 476                 case AUDIT_OBJ_ROLE:
 477                 case AUDIT_OBJ_TYPE:
 478                 case AUDIT_OBJ_LEV_LOW:
 479                 case AUDIT_OBJ_LEV_HIGH:
 480                         str = audit_unpack_string(&bufp, &remain, f->val);
 481                         if (IS_ERR(str))
 482                                 goto exit_free;
 483                         entry->rule.buflen += f->val;
 484
 485                         err = security_audit_rule_init(f->type, f->op, str,
 486                                                        (void **)&f->lsm_rule);
 487                         /* Keep currently invalid fields around in case they
 488                          * become valid after a policy reload. */
 489                         if (err == -EINVAL) {
 490                                 printk(KERN_WARNING "audit rule for LSM "
 491                                        "\'%s\' is invalid\n",  str);
 492                                 err = 0;
 493                         }
 494                         if (err) {
 495                                 kfree(str);
 496                                 goto exit_free;
 497                         } else
 498                                 f->lsm_str = str;
 499                         break;
 500                 case AUDIT_WATCH:
 501                         str = audit_unpack_string(&bufp, &remain, f->val);
 502                         if (IS_ERR(str))
 503                                 goto exit_free;
 504                         entry->rule.buflen += f->val;
 505
 506                         err = audit_to_watch(&entry->rule, str, f->val, f->op);
 507                         if (err) {
 508                                 kfree(str);
 509                                 goto exit_free;
 510                         }
 511                         break;
 512                 case AUDIT_DIR:
 513                         str = audit_unpack_string(&bufp, &remain, f->val);
 514                         if (IS_ERR(str))
 515                                 goto exit_free;
 516                         entry->rule.buflen += f->val;
 517
 518                         err = audit_make_tree(&entry->rule, str, f->op);
 519                         kfree(str);
 520                         if (err)
 521                                 goto exit_free;
 522                         break;
 523                 case AUDIT_INODE:
 524                         err = audit_to_inode(&entry->rule, f);
 525                         if (err)
 526                                 goto exit_free;
 527                         break;
 528                 case AUDIT_FILTERKEY:
 529                         if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
 530                                 goto exit_free;
 531                         str = audit_unpack_string(&bufp, &remain, f->val);
 532                         if (IS_ERR(str))
 533                                 goto exit_free;
 534                         entry->rule.buflen += f->val;
 535                         entry->rule.filterkey = str;
 536                         break;
 537                 case AUDIT_PERM:
 538                         if (f->val & ~15)
 539                                 goto exit_free;
 540                         break;
 541                 case AUDIT_FILETYPE:
 542                         if (f->val & ~S_IFMT)
 543                                 goto exit_free;
 544                         break;
 545                 case AUDIT_FIELD_COMPARE:
 546                         if (f->val > AUDIT_MAX_FIELD_COMPARE)
 547                                 goto exit_free;
 548                         break;
 549                 default:
 550                         goto exit_free;
 551                 }
 552         }
 553
 554         if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
 555                 entry->rule.inode_f = NULL;
 556
 557 exit_nofree:
 558         return entry;
 559
 560 exit_free:
 561         audit_free_rule(entry);
 562         return ERR_PTR(err);
 563 }
 564
 565 /* Pack a filter field's string representation into data block. */
 566 static inline size_t audit_pack_string(void **bufp, const char *str)
 567 {
 568         size_t len = strlen(str);
 569
 570         memcpy(*bufp, str, len);
 571         *bufp += len;
 572
 573         return len;
 574 }
 575
 576 /* Translate kernel rule respresentation to struct audit_rule.
 577  * Exists for backward compatibility with userspace. */
 578 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
 579 {
 580         struct audit_rule *rule;
 581         int i;
 582
 583         rule = kzalloc(sizeof(*rule), GFP_KERNEL);
 584         if (unlikely(!rule))
 585                 return NULL;
 586
 587         rule->flags = krule->flags | krule->listnr;
 588         rule->action = krule->action;
 589         rule->field_count = krule->field_count;
 590         for (i = 0; i < rule->field_count; i++) {
 591                 rule->values[i] = krule->fields[i].val;
 592                 rule->fields[i] = krule->fields[i].type;
 593
 594                 if (krule->vers_ops == 1) {
 595                         if (krule->fields[i].op == Audit_not_equal)
 596                                 rule->fields[i] |= AUDIT_NEGATE;
 597                 } else {
 598                         rule->fields[i] |= audit_ops[krule->fields[i].op];
 599                 }
 600         }
 601         for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
 602
 603         return rule;
 604 }
 605
 606 /* Translate kernel rule respresentation to struct audit_rule_data. */
 607 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
 608 {
 609         struct audit_rule_data *data;
 610         void *bufp;
 611         int i;
 612
 613         data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
 614         if (unlikely(!data))
 615                 return NULL;
 616         memset(data, 0, sizeof(*data));
 617
 618         data->flags = krule->flags | krule->listnr;
 619         data->action = krule->action;
 620         data->field_count = krule->field_count;
 621         bufp = data->buf;
 622         for (i = 0; i < data->field_count; i++) {
 623                 struct audit_field *f = &krule->fields[i];
 624
 625                 data->fields[i] = f->type;
 626                 data->fieldflags[i] = audit_ops[f->op];
 627                 switch(f->type) {
 628                 case AUDIT_SUBJ_USER:
 629                 case AUDIT_SUBJ_ROLE:
 630                 case AUDIT_SUBJ_TYPE:
 631                 case AUDIT_SUBJ_SEN:
 632                 case AUDIT_SUBJ_CLR:
 633                 case AUDIT_OBJ_USER:
 634                 case AUDIT_OBJ_ROLE:
 635                 case AUDIT_OBJ_TYPE:
 636                 case AUDIT_OBJ_LEV_LOW:
 637                 case AUDIT_OBJ_LEV_HIGH:
 638                         data->buflen += data->values[i] =
 639                                 audit_pack_string(&bufp, f->lsm_str);
 640                         break;
 641                 case AUDIT_WATCH:
 642                         data->buflen += data->values[i] =
 643                                 audit_pack_string(&bufp,
 644                                                   audit_watch_path(krule->watch));
 645                         break;
 646                 case AUDIT_DIR:
 647                         data->buflen += data->values[i] =
 648                                 audit_pack_string(&bufp,
 649                                                   audit_tree_path(krule->tree));
 650                         break;
 651                 case AUDIT_FILTERKEY:
 652                         data->buflen += data->values[i] =
 653                                 audit_pack_string(&bufp, krule->filterkey);
 654                         break;
 655                 default:
 656                         data->values[i] = f->val;
 657                 }
 658         }
 659         for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
 660
 661         return data;
 662 }
 663
 664 /* Compare two rules in kernel format.  Considered success if rules
 665  * don't match. */
 666 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
 667 {
 668         int i;
 669
 670         if (a->flags != b->flags ||
 671             a->listnr != b->listnr ||
 672             a->action != b->action ||
 673             a->field_count != b->field_count)
 674                 return 1;
 675
 676         for (i = 0; i < a->field_count; i++) {
 677                 if (a->fields[i].type != b->fields[i].type ||
 678                     a->fields[i].op != b->fields[i].op)
 679                         return 1;
 680
 681                 switch(a->fields[i].type) {
 682                 case AUDIT_SUBJ_USER:
 683                 case AUDIT_SUBJ_ROLE:
 684                 case AUDIT_SUBJ_TYPE:
 685                 case AUDIT_SUBJ_SEN:
 686                 case AUDIT_SUBJ_CLR:
 687                 case AUDIT_OBJ_USER:
 688                 case AUDIT_OBJ_ROLE:
 689                 case AUDIT_OBJ_TYPE:
 690                 case AUDIT_OBJ_LEV_LOW:
 691                 case AUDIT_OBJ_LEV_HIGH:
 692                         if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
 693                                 return 1;
 694                         break;
 695                 case AUDIT_WATCH:
 696                         if (strcmp(audit_watch_path(a->watch),
 697                                    audit_watch_path(b->watch)))
 698                                 return 1;
 699                         break;
 700                 case AUDIT_DIR:
 701                         if (strcmp(audit_tree_path(a->tree),
 702                                    audit_tree_path(b->tree)))
 703                                 return 1;
 704                         break;
 705                 case AUDIT_FILTERKEY:
 706                         /* both filterkeys exist based on above type compare */
 707                         if (strcmp(a->filterkey, b->filterkey))
 708                                 return 1;
 709                         break;
 710                 default:
 711                         if (a->fields[i].val != b->fields[i].val)
 712                                 return 1;
 713                 }
 714         }
 715
 716         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 717                 if (a->mask[i] != b->mask[i])
 718                         return 1;
 719
 720         return 0;
 721 }
 722
 723 /* Duplicate LSM field information.  The lsm_rule is opaque, so must be
 724  * re-initialized. */
 725 static inline int audit_dupe_lsm_field(struct audit_field *df,
 726                                            struct audit_field *sf)
 727 {
 728         int ret = 0;
 729         char *lsm_str;
 730
 731         /* our own copy of lsm_str */
 732         lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
 733         if (unlikely(!lsm_str))
 734                 return -ENOMEM;
 735         df->lsm_str = lsm_str;
 736
 737         /* our own (refreshed) copy of lsm_rule */
 738         ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
 739                                        (void **)&df->lsm_rule);
 740         /* Keep currently invalid fields around in case they
 741          * become valid after a policy reload. */
 742         if (ret == -EINVAL) {
 743                 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
 744                        "invalid\n", df->lsm_str);
 745                 ret = 0;
 746         }
 747
 748         return ret;
 749 }
 750
 751 /* Duplicate an audit rule.  This will be a deep copy with the exception
 752  * of the watch - that pointer is carried over.  The LSM specific fields
 753  * will be updated in the copy.  The point is to be able to replace the old
 754  * rule with the new rule in the filterlist, then free the old rule.
 755  * The rlist element is undefined; list manipulations are handled apart from
 756  * the initial copy. */
 757 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
 758 {
 759         u32 fcount = old->field_count;
 760         struct audit_entry *entry;
 761         struct audit_krule *new;
 762         char *fk;
 763         int i, err = 0;
 764
 765         entry = audit_init_entry(fcount);
 766         if (unlikely(!entry))
 767                 return ERR_PTR(-ENOMEM);
 768
 769         new = &entry->rule;
 770         new->vers_ops = old->vers_ops;
 771         new->flags = old->flags;
 772         new->listnr = old->listnr;
 773         new->action = old->action;
 774         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 775                 new->mask[i] = old->mask[i];
 776         new->prio = old->prio;
 777         new->buflen = old->buflen;
 778         new->inode_f = old->inode_f;
 779         new->field_count = old->field_count;
 780
 781         /*
 782          * note that we are OK with not refcounting here; audit_match_tree()
 783          * never dereferences tree and we can't get false positives there
 784          * since we'd have to have rule gone from the list *and* removed
 785          * before the chunks found by lookup had been allocated, i.e. before
 786          * the beginning of list scan.
 787          */
 788         new->tree = old->tree;
 789         memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
 790
 791         /* deep copy this information, updating the lsm_rule fields, because
 792          * the originals will all be freed when the old rule is freed. */
 793         for (i = 0; i < fcount; i++) {
 794                 switch (new->fields[i].type) {
 795                 case AUDIT_SUBJ_USER:
 796                 case AUDIT_SUBJ_ROLE:
 797                 case AUDIT_SUBJ_TYPE:
 798                 case AUDIT_SUBJ_SEN:
 799                 case AUDIT_SUBJ_CLR:
 800                 case AUDIT_OBJ_USER:
 801                 case AUDIT_OBJ_ROLE:
 802                 case AUDIT_OBJ_TYPE:
 803                 case AUDIT_OBJ_LEV_LOW:
 804                 case AUDIT_OBJ_LEV_HIGH:
 805                         err = audit_dupe_lsm_field(&new->fields[i],
 806                                                        &old->fields[i]);
 807                         break;
 808                 case AUDIT_FILTERKEY:
 809                         fk = kstrdup(old->filterkey, GFP_KERNEL);
 810                         if (unlikely(!fk))
 811                                 err = -ENOMEM;
 812                         else
 813                                 new->filterkey = fk;
 814                 }
 815                 if (err) {
 816                         audit_free_rule(entry);
 817                         return ERR_PTR(err);
 818                 }
 819         }
 820
 821         if (old->watch) {
 822                 audit_get_watch(old->watch);
 823                 new->watch = old->watch;
 824         }
 825
 826         return entry;
 827 }
 828
 829 /* Find an existing audit rule.
 830  * Caller must hold audit_filter_mutex to prevent stale rule data. */
 831 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
 832                                            struct list_head **p)
 833 {
 834         struct audit_entry *e, *found = NULL;
 835         struct list_head *list;
 836         int h;
 837
 838         if (entry->rule.inode_f) {
 839                 h = audit_hash_ino(entry->rule.inode_f->val);
 840                 *p = list = &audit_inode_hash[h];
 841         } else if (entry->rule.watch) {
 842                 /* we don't know the inode number, so must walk entire hash */
 843                 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
 844                         list = &audit_inode_hash[h];
 845                         list_for_each_entry(e, list, list)
 846                                 if (!audit_compare_rule(&entry->rule, &e->rule)) {
 847                                         found = e;
 848                                         goto out;
 849                                 }
 850                 }
 851                 goto out;
 852         } else {
 853                 *p = list = &audit_filter_list[entry->rule.listnr];
 854         }
 855
 856         list_for_each_entry(e, list, list)
 857                 if (!audit_compare_rule(&entry->rule, &e->rule)) {
 858                         found = e;
 859                         goto out;
 860                 }
 861
 862 out:
 863         return found;
 864 }
 865
 866 static u64 prio_low = ~0ULL/2;
 867 static u64 prio_high = ~0ULL/2 - 1;
 868
 869 /* Add rule to given filterlist if not a duplicate. */
 870 static inline int audit_add_rule(struct audit_entry *entry)
 871 {
 872         struct audit_entry *e;
 873         struct audit_watch *watch = entry->rule.watch;
 874         struct audit_tree *tree = entry->rule.tree;
 875         struct list_head *list;
 876         int err;
 877 #ifdef CONFIG_AUDITSYSCALL
 878         int dont_count = 0;
 879
 880         /* If either of these, don't count towards total */
 881         if (entry->rule.listnr == AUDIT_FILTER_USER ||
 882                 entry->rule.listnr == AUDIT_FILTER_TYPE)
 883                 dont_count = 1;
 884 #endif
 885
 886         mutex_lock(&audit_filter_mutex);
 887         e = audit_find_rule(entry, &list);
 888         if (e) {
 889                 mutex_unlock(&audit_filter_mutex);
 890                 err = -EEXIST;
 891                 /* normally audit_add_tree_rule() will free it on failure */
 892                 if (tree)
 893                         audit_put_tree(tree);
 894                 goto error;
 895         }
 896
 897         if (watch) {
 898                 /* audit_filter_mutex is dropped and re-taken during this call */
 899                 err = audit_add_watch(&entry->rule, &list);
 900                 if (err) {
 901                         mutex_unlock(&audit_filter_mutex);
 902                         goto error;
 903                 }
 904         }
 905         if (tree) {
 906                 err = audit_add_tree_rule(&entry->rule);
 907                 if (err) {
 908                         mutex_unlock(&audit_filter_mutex);
 909                         goto error;
 910                 }
 911         }
 912
 913         entry->rule.prio = ~0ULL;
 914         if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
 915                 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
 916                         entry->rule.prio = ++prio_high;
 917                 else
 918                         entry->rule.prio = --prio_low;
 919         }
 920
 921         if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
 922                 list_add(&entry->rule.list,
 923                          &audit_rules_list[entry->rule.listnr]);
 924                 list_add_rcu(&entry->list, list);
 925                 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
 926         } else {
 927                 list_add_tail(&entry->rule.list,
 928                               &audit_rules_list[entry->rule.listnr]);
 929                 list_add_tail_rcu(&entry->list, list);
 930         }
 931 #ifdef CONFIG_AUDITSYSCALL
 932         if (!dont_count)
 933                 audit_n_rules++;
 934
 935         if (!audit_match_signal(entry))
 936                 audit_signals++;
 937 #endif
 938         mutex_unlock(&audit_filter_mutex);
 939
 940         return 0;
 941
 942 error:
 943         if (watch)
 944                 audit_put_watch(watch); /* tmp watch, matches initial get */
 945         return err;
 946 }
 947
 948 /* Remove an existing rule from filterlist. */
 949 static inline int audit_del_rule(struct audit_entry *entry)
 950 {
 951         struct audit_entry  *e;
 952         struct audit_watch *watch = entry->rule.watch;
 953         struct audit_tree *tree = entry->rule.tree;
 954         struct list_head *list;
 955         int ret = 0;
 956 #ifdef CONFIG_AUDITSYSCALL
 957         int dont_count = 0;
 958
 959         /* If either of these, don't count towards total */
 960         if (entry->rule.listnr == AUDIT_FILTER_USER ||
 961                 entry->rule.listnr == AUDIT_FILTER_TYPE)
 962                 dont_count = 1;
 963 #endif
 964
 965         mutex_lock(&audit_filter_mutex);
 966         e = audit_find_rule(entry, &list);
 967         if (!e) {
 968                 mutex_unlock(&audit_filter_mutex);
 969                 ret = -ENOENT;
 970                 goto out;
 971         }
 972
 973         if (e->rule.watch)
 974                 audit_remove_watch_rule(&e->rule);
 975
 976         if (e->rule.tree)
 977                 audit_remove_tree_rule(&e->rule);
 978
 979         list_del_rcu(&e->list);
 980         list_del(&e->rule.list);
 981         call_rcu(&e->rcu, audit_free_rule_rcu);
 982
 983 #ifdef CONFIG_AUDITSYSCALL
 984         if (!dont_count)
 985                 audit_n_rules--;
 986
 987         if (!audit_match_signal(entry))
 988                 audit_signals--;
 989 #endif
 990         mutex_unlock(&audit_filter_mutex);
 991
 992 out:
 993         if (watch)
 994                 audit_put_watch(watch); /* match initial get */
 995         if (tree)
 996                 audit_put_tree(tree);   /* that's the temporary one */
 997
 998         return ret;
 999 }
1000
1001 /* List rules using struct audit_rule.  Exists for backward
1002  * compatibility with userspace. */
1003 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1004 {
1005         struct sk_buff *skb;
1006         struct audit_krule *r;
1007         int i;
1008
1009         /* This is a blocking read, so use audit_filter_mutex instead of rcu
1010          * iterator to sync with list writers. */
1011         for (i=0; i<AUDIT_NR_FILTERS; i++) {
1012                 list_for_each_entry(r, &audit_rules_list[i], list) {
1013                         struct audit_rule *rule;
1014
1015                         rule = audit_krule_to_rule(r);
1016                         if (unlikely(!rule))
1017                                 break;
1018                         skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1019                                          rule, sizeof(*rule));
1020                         if (skb)
1021                                 skb_queue_tail(q, skb);
1022                         kfree(rule);
1023                 }
1024         }
1025         skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1026         if (skb)
1027                 skb_queue_tail(q, skb);
1028 }
1029
1030 /* List rules using struct audit_rule_data. */
1031 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1032 {
1033         struct sk_buff *skb;
1034         struct audit_krule *r;
1035         int i;
1036
1037         /* This is a blocking read, so use audit_filter_mutex instead of rcu
1038          * iterator to sync with list writers. */
1039         for (i=0; i<AUDIT_NR_FILTERS; i++) {
1040                 list_for_each_entry(r, &audit_rules_list[i], list) {
1041                         struct audit_rule_data *data;
1042
1043                         data = audit_krule_to_data(r);
1044                         if (unlikely(!data))
1045                                 break;
1046                         skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1047                                          data, sizeof(*data) + data->buflen);
1048                         if (skb)
1049                                 skb_queue_tail(q, skb);
1050                         kfree(data);
1051                 }
1052         }
1053         skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1054         if (skb)
1055                 skb_queue_tail(q, skb);
1056 }
1057
1058 /* Log rule additions and removals */
1059 static void audit_log_rule_change(uid_t loginuid, u32 sessionid, u32 sid,
1060                                   char *action, struct audit_krule *rule,
1061                                   int res)
1062 {
1063         struct audit_buffer *ab;
1064
1065         if (!audit_enabled)
1066                 return;
1067
1068         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1069         if (!ab)
1070                 return;
1071         audit_log_format(ab, "auid=%u ses=%u", loginuid, sessionid);
1072         if (sid) {
1073                 char *ctx = NULL;
1074                 u32 len;
1075                 if (security_secid_to_secctx(sid, &ctx, &len))
1076                         audit_log_format(ab, " ssid=%u", sid);
1077                 else {
1078                         audit_log_format(ab, " subj=%s", ctx);
1079                         security_release_secctx(ctx, len);
1080                 }
1081         }
1082         audit_log_format(ab, " op=");
1083         audit_log_string(ab, action);
1084         audit_log_key(ab, rule->filterkey);
1085         audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1086         audit_log_end(ab);
1087 }
1088
1089 /**
1090  * audit_receive_filter - apply all rules to the specified message type
1091  * @type: audit message type
1092  * @pid: target pid for netlink audit messages
1093  * @uid: target uid for netlink audit messages
1094  * @seq: netlink audit message sequence (serial) number
1095  * @data: payload data
1096  * @datasz: size of payload data
1097  * @loginuid: loginuid of sender
1098  * @sessionid: sessionid for netlink audit message
1099  * @sid: SE Linux Security ID of sender
1100  */
1101 int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1102                          size_t datasz, uid_t loginuid, u32 sessionid, u32 sid)
1103 {
1104         struct task_struct *tsk;
1105         struct audit_netlink_list *dest;
1106         int err = 0;
1107         struct audit_entry *entry;
1108
1109         switch (type) {
1110         case AUDIT_LIST:
1111         case AUDIT_LIST_RULES:
1112                 /* We can't just spew out the rules here because we might fill
1113                  * the available socket buffer space and deadlock waiting for
1114                  * auditctl to read from it... which isn't ever going to
1115                  * happen if we're actually running in the context of auditctl
1116                  * trying to _send_ the stuff */
1117
1118                 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1119                 if (!dest)
1120                         return -ENOMEM;
1121                 dest->pid = pid;
1122                 skb_queue_head_init(&dest->q);
1123
1124                 mutex_lock(&audit_filter_mutex);
1125                 if (type == AUDIT_LIST)
1126                         audit_list(pid, seq, &dest->q);
1127                 else
1128                         audit_list_rules(pid, seq, &dest->q);
1129                 mutex_unlock(&audit_filter_mutex);
1130
1131                 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1132                 if (IS_ERR(tsk)) {
1133                         skb_queue_purge(&dest->q);
1134                         kfree(dest);
1135                         err = PTR_ERR(tsk);
1136                 }
1137                 break;
1138         case AUDIT_ADD:
1139         case AUDIT_ADD_RULE:
1140                 if (type == AUDIT_ADD)
1141                         entry = audit_rule_to_entry(data);
1142                 else
1143                         entry = audit_data_to_entry(data, datasz);
1144                 if (IS_ERR(entry))
1145                         return PTR_ERR(entry);
1146
1147                 err = audit_add_rule(entry);
1148                 audit_log_rule_change(loginuid, sessionid, sid, "add rule",
1149                                       &entry->rule, !err);
1150
1151                 if (err)
1152                         audit_free_rule(entry);
1153                 break;
1154         case AUDIT_DEL:
1155         case AUDIT_DEL_RULE:
1156                 if (type == AUDIT_DEL)
1157                         entry = audit_rule_to_entry(data);
1158                 else
1159                         entry = audit_data_to_entry(data, datasz);
1160                 if (IS_ERR(entry))
1161                         return PTR_ERR(entry);
1162
1163                 err = audit_del_rule(entry);
1164                 audit_log_rule_change(loginuid, sessionid, sid, "remove rule",
1165                                       &entry->rule, !err);
1166
1167                 audit_free_rule(entry);
1168                 break;
1169         default:
1170                 return -EINVAL;
1171         }
1172
1173         return err;
1174 }
1175
1176 int audit_comparator(u32 left, u32 op, u32 right)
1177 {
1178         switch (op) {
1179         case Audit_equal:
1180                 return (left == right);
1181         case Audit_not_equal:
1182                 return (left != right);
1183         case Audit_lt:
1184                 return (left < right);
1185         case Audit_le:
1186                 return (left <= right);
1187         case Audit_gt:
1188                 return (left > right);
1189         case Audit_ge:
1190                 return (left >= right);
1191         case Audit_bitmask:
1192                 return (left & right);
1193         case Audit_bittest:
1194                 return ((left & right) == right);
1195         default:
1196                 BUG();
1197                 return 0;
1198         }
1199 }
1200
1201 /* Compare given dentry name with last component in given path,
1202  * return of 0 indicates a match. */
1203 int audit_compare_dname_path(const char *dname, const char *path,
1204                              int *dirlen)
1205 {
1206         int dlen, plen;
1207         const char *p;
1208
1209         if (!dname || !path)
1210                 return 1;
1211
1212         dlen = strlen(dname);
1213         plen = strlen(path);
1214         if (plen < dlen)
1215                 return 1;
1216
1217         /* disregard trailing slashes */
1218         p = path + plen - 1;
1219         while ((*p == '/') && (p > path))
1220                 p--;
1221
1222         /* find last path component */
1223         p = p - dlen + 1;
1224         if (p < path)
1225                 return 1;
1226         else if (p > path) {
1227                 if (*--p != '/')
1228                         return 1;
1229                 else
1230                         p++;
1231         }
1232
1233         /* return length of path's directory component */
1234         if (dirlen)
1235                 *dirlen = p - path;
1236         return strncmp(p, dname, dlen);
1237 }
1238
1239 static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1240                                    struct audit_krule *rule,
1241                                    enum audit_state *state)
1242 {
1243         int i;
1244
1245         for (i = 0; i < rule->field_count; i++) {
1246                 struct audit_field *f = &rule->fields[i];
1247                 int result = 0;
1248                 u32 sid;
1249
1250                 switch (f->type) {
1251                 case AUDIT_PID:
1252                         result = audit_comparator(cb->creds.pid, f->op, f->val);
1253                         break;
1254                 case AUDIT_UID:
1255                         result = audit_comparator(cb->creds.uid, f->op, f->val);
1256                         break;
1257                 case AUDIT_GID:
1258                         result = audit_comparator(cb->creds.gid, f->op, f->val);
1259                         break;
1260                 case AUDIT_LOGINUID:
1261                         result = audit_comparator(audit_get_loginuid(current),
1262                                                   f->op, f->val);
1263                         break;
1264                 case AUDIT_SUBJ_USER:
1265                 case AUDIT_SUBJ_ROLE:
1266                 case AUDIT_SUBJ_TYPE:
1267                 case AUDIT_SUBJ_SEN:
1268                 case AUDIT_SUBJ_CLR:
1269                         if (f->lsm_rule) {
1270                                 security_task_getsecid(current, &sid);
1271                                 result = security_audit_rule_match(sid,
1272                                                                    f->type,
1273                                                                    f->op,
1274                                                                    f->lsm_rule,
1275                                                                    NULL);
1276                         }
1277                         break;
1278                 }
1279
1280                 if (!result)
1281                         return 0;
1282         }
1283         switch (rule->action) {
1284         case AUDIT_NEVER:    *state = AUDIT_DISABLED;       break;
1285         case AUDIT_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
1286         }
1287         return 1;
1288 }
1289
1290 int audit_filter_user(struct netlink_skb_parms *cb)
1291 {
1292         enum audit_state state = AUDIT_DISABLED;
1293         struct audit_entry *e;
1294         int ret = 1;
1295
1296         rcu_read_lock();
1297         list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1298                 if (audit_filter_user_rules(cb, &e->rule, &state)) {
1299                         if (state == AUDIT_DISABLED)
1300                                 ret = 0;
1301                         break;
1302                 }
1303         }
1304         rcu_read_unlock();
1305
1306         return ret; /* Audit by default */
1307 }
1308
1309 int audit_filter_type(int type)
1310 {
1311         struct audit_entry *e;
1312         int result = 0;
1313
1314         rcu_read_lock();
1315         if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1316                 goto unlock_and_return;
1317
1318         list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1319                                 list) {
1320                 int i;
1321                 for (i = 0; i < e->rule.field_count; i++) {
1322                         struct audit_field *f = &e->rule.fields[i];
1323                         if (f->type == AUDIT_MSGTYPE) {
1324                                 result = audit_comparator(type, f->op, f->val);
1325                                 if (!result)
1326                                         break;
1327                         }
1328                 }
1329                 if (result)
1330                         goto unlock_and_return;
1331         }
1332 unlock_and_return:
1333         rcu_read_unlock();
1334         return result;
1335 }
1336
1337 static int update_lsm_rule(struct audit_krule *r)
1338 {
1339         struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1340         struct audit_entry *nentry;
1341         int err = 0;
1342
1343         if (!security_audit_rule_known(r))
1344                 return 0;
1345
1346         nentry = audit_dupe_rule(r);
1347         if (IS_ERR(nentry)) {
1348                 /* save the first error encountered for the
1349                  * return value */
1350                 err = PTR_ERR(nentry);
1351                 audit_panic("error updating LSM filters");
1352                 if (r->watch)
1353                         list_del(&r->rlist);
1354                 list_del_rcu(&entry->list);
1355                 list_del(&r->list);
1356         } else {
1357                 if (r->watch || r->tree)
1358                         list_replace_init(&r->rlist, &nentry->rule.rlist);
1359                 list_replace_rcu(&entry->list, &nentry->list);
1360                 list_replace(&r->list, &nentry->rule.list);
1361         }
1362         call_rcu(&entry->rcu, audit_free_rule_rcu);
1363
1364         return err;
1365 }
1366
1367 /* This function will re-initialize the lsm_rule field of all applicable rules.
1368  * It will traverse the filter lists serarching for rules that contain LSM
1369  * specific filter fields.  When such a rule is found, it is copied, the
1370  * LSM field is re-initialized, and the old rule is replaced with the
1371  * updated rule. */
1372 int audit_update_lsm_rules(void)
1373 {
1374         struct audit_krule *r, *n;
1375         int i, err = 0;
1376
1377         /* audit_filter_mutex synchronizes the writers */
1378         mutex_lock(&audit_filter_mutex);
1379
1380         for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1381                 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1382                         int res = update_lsm_rule(r);
1383                         if (!err)
1384                                 err = res;
1385                 }
1386         }
1387         mutex_unlock(&audit_filter_mutex);
1388
1389         return err;
1390 }