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                         err = -EINVAL;
 530                         if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
 531                                 goto exit_free;
 532                         str = audit_unpack_string(&bufp, &remain, f->val);
 533                         if (IS_ERR(str))
 534                                 goto exit_free;
 535                         entry->rule.buflen += f->val;
 536                         entry->rule.filterkey = str;
 537                         break;
 538                 case AUDIT_PERM:
 539                         if (f->val & ~15)
 540                                 goto exit_free;
 541                         break;
 542                 case AUDIT_FILETYPE:
 543                         if (f->val & ~S_IFMT)
 544                                 goto exit_free;
 545                         break;
 546                 default:
 547                         goto exit_free;
 548                 }
 549         }
 550
 551         if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
 552                 entry->rule.inode_f = NULL;
 553
 554 exit_nofree:
 555         return entry;
 556
 557 exit_free:
 558         audit_free_rule(entry);
 559         return ERR_PTR(err);
 560 }
 561
 562 /* Pack a filter field's string representation into data block. */
 563 static inline size_t audit_pack_string(void **bufp, const char *str)
 564 {
 565         size_t len = strlen(str);
 566
 567         memcpy(*bufp, str, len);
 568         *bufp += len;
 569
 570         return len;
 571 }
 572
 573 /* Translate kernel rule respresentation to struct audit_rule.
 574  * Exists for backward compatibility with userspace. */
 575 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
 576 {
 577         struct audit_rule *rule;
 578         int i;
 579
 580         rule = kzalloc(sizeof(*rule), GFP_KERNEL);
 581         if (unlikely(!rule))
 582                 return NULL;
 583
 584         rule->flags = krule->flags | krule->listnr;
 585         rule->action = krule->action;
 586         rule->field_count = krule->field_count;
 587         for (i = 0; i < rule->field_count; i++) {
 588                 rule->values[i] = krule->fields[i].val;
 589                 rule->fields[i] = krule->fields[i].type;
 590
 591                 if (krule->vers_ops == 1) {
 592                         if (krule->fields[i].op == Audit_not_equal)
 593                                 rule->fields[i] |= AUDIT_NEGATE;
 594                 } else {
 595                         rule->fields[i] |= audit_ops[krule->fields[i].op];
 596                 }
 597         }
 598         for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
 599
 600         return rule;
 601 }
 602
 603 /* Translate kernel rule respresentation to struct audit_rule_data. */
 604 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
 605 {
 606         struct audit_rule_data *data;
 607         void *bufp;
 608         int i;
 609
 610         data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
 611         if (unlikely(!data))
 612                 return NULL;
 613         memset(data, 0, sizeof(*data));
 614
 615         data->flags = krule->flags | krule->listnr;
 616         data->action = krule->action;
 617         data->field_count = krule->field_count;
 618         bufp = data->buf;
 619         for (i = 0; i < data->field_count; i++) {
 620                 struct audit_field *f = &krule->fields[i];
 621
 622                 data->fields[i] = f->type;
 623                 data->fieldflags[i] = audit_ops[f->op];
 624                 switch(f->type) {
 625                 case AUDIT_SUBJ_USER:
 626                 case AUDIT_SUBJ_ROLE:
 627                 case AUDIT_SUBJ_TYPE:
 628                 case AUDIT_SUBJ_SEN:
 629                 case AUDIT_SUBJ_CLR:
 630                 case AUDIT_OBJ_USER:
 631                 case AUDIT_OBJ_ROLE:
 632                 case AUDIT_OBJ_TYPE:
 633                 case AUDIT_OBJ_LEV_LOW:
 634                 case AUDIT_OBJ_LEV_HIGH:
 635                         data->buflen += data->values[i] =
 636                                 audit_pack_string(&bufp, f->lsm_str);
 637                         break;
 638                 case AUDIT_WATCH:
 639                         data->buflen += data->values[i] =
 640                                 audit_pack_string(&bufp,
 641                                                   audit_watch_path(krule->watch));
 642                         break;
 643                 case AUDIT_DIR:
 644                         data->buflen += data->values[i] =
 645                                 audit_pack_string(&bufp,
 646                                                   audit_tree_path(krule->tree));
 647                         break;
 648                 case AUDIT_FILTERKEY:
 649                         data->buflen += data->values[i] =
 650                                 audit_pack_string(&bufp, krule->filterkey);
 651                         break;
 652                 default:
 653                         data->values[i] = f->val;
 654                 }
 655         }
 656         for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
 657
 658         return data;
 659 }
 660
 661 /* Compare two rules in kernel format.  Considered success if rules
 662  * don't match. */
 663 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
 664 {
 665         int i;
 666
 667         if (a->flags != b->flags ||
 668             a->listnr != b->listnr ||
 669             a->action != b->action ||
 670             a->field_count != b->field_count)
 671                 return 1;
 672
 673         for (i = 0; i < a->field_count; i++) {
 674                 if (a->fields[i].type != b->fields[i].type ||
 675                     a->fields[i].op != b->fields[i].op)
 676                         return 1;
 677
 678                 switch(a->fields[i].type) {
 679                 case AUDIT_SUBJ_USER:
 680                 case AUDIT_SUBJ_ROLE:
 681                 case AUDIT_SUBJ_TYPE:
 682                 case AUDIT_SUBJ_SEN:
 683                 case AUDIT_SUBJ_CLR:
 684                 case AUDIT_OBJ_USER:
 685                 case AUDIT_OBJ_ROLE:
 686                 case AUDIT_OBJ_TYPE:
 687                 case AUDIT_OBJ_LEV_LOW:
 688                 case AUDIT_OBJ_LEV_HIGH:
 689                         if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
 690                                 return 1;
 691                         break;
 692                 case AUDIT_WATCH:
 693                         if (strcmp(audit_watch_path(a->watch),
 694                                    audit_watch_path(b->watch)))
 695                                 return 1;
 696                         break;
 697                 case AUDIT_DIR:
 698                         if (strcmp(audit_tree_path(a->tree),
 699                                    audit_tree_path(b->tree)))
 700                                 return 1;
 701                         break;
 702                 case AUDIT_FILTERKEY:
 703                         /* both filterkeys exist based on above type compare */
 704                         if (strcmp(a->filterkey, b->filterkey))
 705                                 return 1;
 706                         break;
 707                 default:
 708                         if (a->fields[i].val != b->fields[i].val)
 709                                 return 1;
 710                 }
 711         }
 712
 713         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 714                 if (a->mask[i] != b->mask[i])
 715                         return 1;
 716
 717         return 0;
 718 }
 719
 720 /* Duplicate LSM field information.  The lsm_rule is opaque, so must be
 721  * re-initialized. */
 722 static inline int audit_dupe_lsm_field(struct audit_field *df,
 723                                            struct audit_field *sf)
 724 {
 725         int ret = 0;
 726         char *lsm_str;
 727
 728         /* our own copy of lsm_str */
 729         lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
 730         if (unlikely(!lsm_str))
 731                 return -ENOMEM;
 732         df->lsm_str = lsm_str;
 733
 734         /* our own (refreshed) copy of lsm_rule */
 735         ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
 736                                        (void **)&df->lsm_rule);
 737         /* Keep currently invalid fields around in case they
 738          * become valid after a policy reload. */
 739         if (ret == -EINVAL) {
 740                 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
 741                        "invalid\n", df->lsm_str);
 742                 ret = 0;
 743         }
 744
 745         return ret;
 746 }
 747
 748 /* Duplicate an audit rule.  This will be a deep copy with the exception
 749  * of the watch - that pointer is carried over.  The LSM specific fields
 750  * will be updated in the copy.  The point is to be able to replace the old
 751  * rule with the new rule in the filterlist, then free the old rule.
 752  * The rlist element is undefined; list manipulations are handled apart from
 753  * the initial copy. */
 754 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
 755 {
 756         u32 fcount = old->field_count;
 757         struct audit_entry *entry;
 758         struct audit_krule *new;
 759         char *fk;
 760         int i, err = 0;
 761
 762         entry = audit_init_entry(fcount);
 763         if (unlikely(!entry))
 764                 return ERR_PTR(-ENOMEM);
 765
 766         new = &entry->rule;
 767         new->vers_ops = old->vers_ops;
 768         new->flags = old->flags;
 769         new->listnr = old->listnr;
 770         new->action = old->action;
 771         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 772                 new->mask[i] = old->mask[i];
 773         new->prio = old->prio;
 774         new->buflen = old->buflen;
 775         new->inode_f = old->inode_f;
 776         new->field_count = old->field_count;
 777
 778         /*
 779          * note that we are OK with not refcounting here; audit_match_tree()
 780          * never dereferences tree and we can't get false positives there
 781          * since we'd have to have rule gone from the list *and* removed
 782          * before the chunks found by lookup had been allocated, i.e. before
 783          * the beginning of list scan.
 784          */
 785         new->tree = old->tree;
 786         memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
 787
 788         /* deep copy this information, updating the lsm_rule fields, because
 789          * the originals will all be freed when the old rule is freed. */
 790         for (i = 0; i < fcount; i++) {
 791                 switch (new->fields[i].type) {
 792                 case AUDIT_SUBJ_USER:
 793                 case AUDIT_SUBJ_ROLE:
 794                 case AUDIT_SUBJ_TYPE:
 795                 case AUDIT_SUBJ_SEN:
 796                 case AUDIT_SUBJ_CLR:
 797                 case AUDIT_OBJ_USER:
 798                 case AUDIT_OBJ_ROLE:
 799                 case AUDIT_OBJ_TYPE:
 800                 case AUDIT_OBJ_LEV_LOW:
 801                 case AUDIT_OBJ_LEV_HIGH:
 802                         err = audit_dupe_lsm_field(&new->fields[i],
 803                                                        &old->fields[i]);
 804                         break;
 805                 case AUDIT_FILTERKEY:
 806                         fk = kstrdup(old->filterkey, GFP_KERNEL);
 807                         if (unlikely(!fk))
 808                                 err = -ENOMEM;
 809                         else
 810                                 new->filterkey = fk;
 811                 }
 812                 if (err) {
 813                         audit_free_rule(entry);
 814                         return ERR_PTR(err);
 815                 }
 816         }
 817
 818         if (old->watch) {
 819                 audit_get_watch(old->watch);
 820                 new->watch = old->watch;
 821         }
 822
 823         return entry;
 824 }
 825
 826 /* Find an existing audit rule.
 827  * Caller must hold audit_filter_mutex to prevent stale rule data. */
 828 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
 829                                            struct list_head **p)
 830 {
 831         struct audit_entry *e, *found = NULL;
 832         struct list_head *list;
 833         int h;
 834
 835         if (entry->rule.inode_f) {
 836                 h = audit_hash_ino(entry->rule.inode_f->val);
 837                 *p = list = &audit_inode_hash[h];
 838         } else if (entry->rule.watch) {
 839                 /* we don't know the inode number, so must walk entire hash */
 840                 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
 841                         list = &audit_inode_hash[h];
 842                         list_for_each_entry(e, list, list)
 843                                 if (!audit_compare_rule(&entry->rule, &e->rule)) {
 844                                         found = e;
 845                                         goto out;
 846                                 }
 847                 }
 848                 goto out;
 849         } else {
 850                 *p = list = &audit_filter_list[entry->rule.listnr];
 851         }
 852
 853         list_for_each_entry(e, list, list)
 854                 if (!audit_compare_rule(&entry->rule, &e->rule)) {
 855                         found = e;
 856                         goto out;
 857                 }
 858
 859 out:
 860         return found;
 861 }
 862
 863 static u64 prio_low = ~0ULL/2;
 864 static u64 prio_high = ~0ULL/2 - 1;
 865
 866 /* Add rule to given filterlist if not a duplicate. */
 867 static inline int audit_add_rule(struct audit_entry *entry)
 868 {
 869         struct audit_entry *e;
 870         struct audit_watch *watch = entry->rule.watch;
 871         struct audit_tree *tree = entry->rule.tree;
 872         struct list_head *list;
 873         int err;
 874 #ifdef CONFIG_AUDITSYSCALL
 875         int dont_count = 0;
 876
 877         /* If either of these, don't count towards total */
 878         if (entry->rule.listnr == AUDIT_FILTER_USER ||
 879                 entry->rule.listnr == AUDIT_FILTER_TYPE)
 880                 dont_count = 1;
 881 #endif
 882
 883         mutex_lock(&audit_filter_mutex);
 884         e = audit_find_rule(entry, &list);
 885         if (e) {
 886                 mutex_unlock(&audit_filter_mutex);
 887                 err = -EEXIST;
 888                 /* normally audit_add_tree_rule() will free it on failure */
 889                 if (tree)
 890                         audit_put_tree(tree);
 891                 goto error;
 892         }
 893
 894         if (watch) {
 895                 /* audit_filter_mutex is dropped and re-taken during this call */
 896                 err = audit_add_watch(&entry->rule, &list);
 897                 if (err) {
 898                         mutex_unlock(&audit_filter_mutex);
 899                         goto error;
 900                 }
 901         }
 902         if (tree) {
 903                 err = audit_add_tree_rule(&entry->rule);
 904                 if (err) {
 905                         mutex_unlock(&audit_filter_mutex);
 906                         goto error;
 907                 }
 908         }
 909
 910         entry->rule.prio = ~0ULL;
 911         if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
 912                 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
 913                         entry->rule.prio = ++prio_high;
 914                 else
 915                         entry->rule.prio = --prio_low;
 916         }
 917
 918         if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
 919                 list_add(&entry->rule.list,
 920                          &audit_rules_list[entry->rule.listnr]);
 921                 list_add_rcu(&entry->list, list);
 922                 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
 923         } else {
 924                 list_add_tail(&entry->rule.list,
 925                               &audit_rules_list[entry->rule.listnr]);
 926                 list_add_tail_rcu(&entry->list, list);
 927         }
 928 #ifdef CONFIG_AUDITSYSCALL
 929         if (!dont_count)
 930                 audit_n_rules++;
 931
 932         if (!audit_match_signal(entry))
 933                 audit_signals++;
 934 #endif
 935         mutex_unlock(&audit_filter_mutex);
 936
 937         return 0;
 938
 939 error:
 940         if (watch)
 941                 audit_put_watch(watch); /* tmp watch, matches initial get */
 942         return err;
 943 }
 944
 945 /* Remove an existing rule from filterlist. */
 946 static inline int audit_del_rule(struct audit_entry *entry)
 947 {
 948         struct audit_entry  *e;
 949         struct audit_watch *watch = entry->rule.watch;
 950         struct audit_tree *tree = entry->rule.tree;
 951         struct list_head *list;
 952         int ret = 0;
 953 #ifdef CONFIG_AUDITSYSCALL
 954         int dont_count = 0;
 955
 956         /* If either of these, don't count towards total */
 957         if (entry->rule.listnr == AUDIT_FILTER_USER ||
 958                 entry->rule.listnr == AUDIT_FILTER_TYPE)
 959                 dont_count = 1;
 960 #endif
 961
 962         mutex_lock(&audit_filter_mutex);
 963         e = audit_find_rule(entry, &list);
 964         if (!e) {
 965                 mutex_unlock(&audit_filter_mutex);
 966                 ret = -ENOENT;
 967                 goto out;
 968         }
 969
 970         if (e->rule.watch)
 971                 audit_remove_watch_rule(&e->rule);
 972
 973         if (e->rule.tree)
 974                 audit_remove_tree_rule(&e->rule);
 975
 976         list_del_rcu(&e->list);
 977         list_del(&e->rule.list);
 978         call_rcu(&e->rcu, audit_free_rule_rcu);
 979
 980 #ifdef CONFIG_AUDITSYSCALL
 981         if (!dont_count)
 982                 audit_n_rules--;
 983
 984         if (!audit_match_signal(entry))
 985                 audit_signals--;
 986 #endif
 987         mutex_unlock(&audit_filter_mutex);
 988
 989 out:
 990         if (watch)
 991                 audit_put_watch(watch); /* match initial get */
 992         if (tree)
 993                 audit_put_tree(tree);   /* that's the temporary one */
 994
 995         return ret;
 996 }
 997
 998 /* List rules using struct audit_rule.  Exists for backward
 999  * compatibility with userspace. */
1000 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1001 {
1002         struct sk_buff *skb;
1003         struct audit_krule *r;
1004         int i;
1005
1006         /* This is a blocking read, so use audit_filter_mutex instead of rcu
1007          * iterator to sync with list writers. */
1008         for (i=0; i<AUDIT_NR_FILTERS; i++) {
1009                 list_for_each_entry(r, &audit_rules_list[i], list) {
1010                         struct audit_rule *rule;
1011
1012                         rule = audit_krule_to_rule(r);
1013                         if (unlikely(!rule))
1014                                 break;
1015                         skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1016                                          rule, sizeof(*rule));
1017                         if (skb)
1018                                 skb_queue_tail(q, skb);
1019                         kfree(rule);
1020                 }
1021         }
1022         skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1023         if (skb)
1024                 skb_queue_tail(q, skb);
1025 }
1026
1027 /* List rules using struct audit_rule_data. */
1028 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1029 {
1030         struct sk_buff *skb;
1031         struct audit_krule *r;
1032         int i;
1033
1034         /* This is a blocking read, so use audit_filter_mutex instead of rcu
1035          * iterator to sync with list writers. */
1036         for (i=0; i<AUDIT_NR_FILTERS; i++) {
1037                 list_for_each_entry(r, &audit_rules_list[i], list) {
1038                         struct audit_rule_data *data;
1039
1040                         data = audit_krule_to_data(r);
1041                         if (unlikely(!data))
1042                                 break;
1043                         skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1044                                          data, sizeof(*data) + data->buflen);
1045                         if (skb)
1046                                 skb_queue_tail(q, skb);
1047                         kfree(data);
1048                 }
1049         }
1050         skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1051         if (skb)
1052                 skb_queue_tail(q, skb);
1053 }
1054
1055 /* Log rule additions and removals */
1056 static void audit_log_rule_change(uid_t loginuid, u32 sessionid, u32 sid,
1057                                   char *action, struct audit_krule *rule,
1058                                   int res)
1059 {
1060         struct audit_buffer *ab;
1061
1062         if (!audit_enabled)
1063                 return;
1064
1065         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1066         if (!ab)
1067                 return;
1068         audit_log_format(ab, "auid=%u ses=%u", loginuid, sessionid);
1069         if (sid) {
1070                 char *ctx = NULL;
1071                 u32 len;
1072                 if (security_secid_to_secctx(sid, &ctx, &len))
1073                         audit_log_format(ab, " ssid=%u", sid);
1074                 else {
1075                         audit_log_format(ab, " subj=%s", ctx);
1076                         security_release_secctx(ctx, len);
1077                 }
1078         }
1079         audit_log_format(ab, " op=");
1080         audit_log_string(ab, action);
1081         audit_log_key(ab, rule->filterkey);
1082         audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1083         audit_log_end(ab);
1084 }
1085
1086 /**
1087  * audit_receive_filter - apply all rules to the specified message type
1088  * @type: audit message type
1089  * @pid: target pid for netlink audit messages
1090  * @uid: target uid for netlink audit messages
1091  * @seq: netlink audit message sequence (serial) number
1092  * @data: payload data
1093  * @datasz: size of payload data
1094  * @loginuid: loginuid of sender
1095  * @sessionid: sessionid for netlink audit message
1096  * @sid: SE Linux Security ID of sender
1097  */
1098 int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1099                          size_t datasz, uid_t loginuid, u32 sessionid, u32 sid)
1100 {
1101         struct task_struct *tsk;
1102         struct audit_netlink_list *dest;
1103         int err = 0;
1104         struct audit_entry *entry;
1105
1106         switch (type) {
1107         case AUDIT_LIST:
1108         case AUDIT_LIST_RULES:
1109                 /* We can't just spew out the rules here because we might fill
1110                  * the available socket buffer space and deadlock waiting for
1111                  * auditctl to read from it... which isn't ever going to
1112                  * happen if we're actually running in the context of auditctl
1113                  * trying to _send_ the stuff */
1114
1115                 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1116                 if (!dest)
1117                         return -ENOMEM;
1118                 dest->pid = pid;
1119                 skb_queue_head_init(&dest->q);
1120
1121                 mutex_lock(&audit_filter_mutex);
1122                 if (type == AUDIT_LIST)
1123                         audit_list(pid, seq, &dest->q);
1124                 else
1125                         audit_list_rules(pid, seq, &dest->q);
1126                 mutex_unlock(&audit_filter_mutex);
1127
1128                 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1129                 if (IS_ERR(tsk)) {
1130                         skb_queue_purge(&dest->q);
1131                         kfree(dest);
1132                         err = PTR_ERR(tsk);
1133                 }
1134                 break;
1135         case AUDIT_ADD:
1136         case AUDIT_ADD_RULE:
1137                 if (type == AUDIT_ADD)
1138                         entry = audit_rule_to_entry(data);
1139                 else
1140                         entry = audit_data_to_entry(data, datasz);
1141                 if (IS_ERR(entry))
1142                         return PTR_ERR(entry);
1143
1144                 err = audit_add_rule(entry);
1145                 audit_log_rule_change(loginuid, sessionid, sid, "add rule",
1146                                       &entry->rule, !err);
1147
1148                 if (err)
1149                         audit_free_rule(entry);
1150                 break;
1151         case AUDIT_DEL:
1152         case AUDIT_DEL_RULE:
1153                 if (type == AUDIT_DEL)
1154                         entry = audit_rule_to_entry(data);
1155                 else
1156                         entry = audit_data_to_entry(data, datasz);
1157                 if (IS_ERR(entry))
1158                         return PTR_ERR(entry);
1159
1160                 err = audit_del_rule(entry);
1161                 audit_log_rule_change(loginuid, sessionid, sid, "remove rule",
1162                                       &entry->rule, !err);
1163
1164                 audit_free_rule(entry);
1165                 break;
1166         default:
1167                 return -EINVAL;
1168         }
1169
1170         return err;
1171 }
1172
1173 int audit_comparator(u32 left, u32 op, u32 right)
1174 {
1175         switch (op) {
1176         case Audit_equal:
1177                 return (left == right);
1178         case Audit_not_equal:
1179                 return (left != right);
1180         case Audit_lt:
1181                 return (left < right);
1182         case Audit_le:
1183                 return (left <= right);
1184         case Audit_gt:
1185                 return (left > right);
1186         case Audit_ge:
1187                 return (left >= right);
1188         case Audit_bitmask:
1189                 return (left & right);
1190         case Audit_bittest:
1191                 return ((left & right) == right);
1192         default:
1193                 BUG();
1194                 return 0;
1195         }
1196 }
1197
1198 /* Compare given dentry name with last component in given path,
1199  * return of 0 indicates a match. */
1200 int audit_compare_dname_path(const char *dname, const char *path,
1201                              int *dirlen)
1202 {
1203         int dlen, plen;
1204         const char *p;
1205
1206         if (!dname || !path)
1207                 return 1;
1208
1209         dlen = strlen(dname);
1210         plen = strlen(path);
1211         if (plen < dlen)
1212                 return 1;
1213
1214         /* disregard trailing slashes */
1215         p = path + plen - 1;
1216         while ((*p == '/') && (p > path))
1217                 p--;
1218
1219         /* find last path component */
1220         p = p - dlen + 1;
1221         if (p < path)
1222                 return 1;
1223         else if (p > path) {
1224                 if (*--p != '/')
1225                         return 1;
1226                 else
1227                         p++;
1228         }
1229
1230         /* return length of path's directory component */
1231         if (dirlen)
1232                 *dirlen = p - path;
1233         return strncmp(p, dname, dlen);
1234 }
1235
1236 static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1237                                    struct audit_krule *rule,
1238                                    enum audit_state *state)
1239 {
1240         int i;
1241
1242         for (i = 0; i < rule->field_count; i++) {
1243                 struct audit_field *f = &rule->fields[i];
1244                 int result = 0;
1245                 u32 sid;
1246
1247                 switch (f->type) {
1248                 case AUDIT_PID:
1249                         result = audit_comparator(cb->creds.pid, f->op, f->val);
1250                         break;
1251                 case AUDIT_UID:
1252                         result = audit_comparator(cb->creds.uid, f->op, f->val);
1253                         break;
1254                 case AUDIT_GID:
1255                         result = audit_comparator(cb->creds.gid, f->op, f->val);
1256                         break;
1257                 case AUDIT_LOGINUID:
1258                         result = audit_comparator(audit_get_loginuid(current),
1259                                                   f->op, f->val);
1260                         break;
1261                 case AUDIT_SUBJ_USER:
1262                 case AUDIT_SUBJ_ROLE:
1263                 case AUDIT_SUBJ_TYPE:
1264                 case AUDIT_SUBJ_SEN:
1265                 case AUDIT_SUBJ_CLR:
1266                         if (f->lsm_rule) {
1267                                 security_task_getsecid(current, &sid);
1268                                 result = security_audit_rule_match(sid,
1269                                                                    f->type,
1270                                                                    f->op,
1271                                                                    f->lsm_rule,
1272                                                                    NULL);
1273                         }
1274                         break;
1275                 }
1276
1277                 if (!result)
1278                         return 0;
1279         }
1280         switch (rule->action) {
1281         case AUDIT_NEVER:    *state = AUDIT_DISABLED;       break;
1282         case AUDIT_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
1283         }
1284         return 1;
1285 }
1286
1287 int audit_filter_user(struct netlink_skb_parms *cb)
1288 {
1289         enum audit_state state = AUDIT_DISABLED;
1290         struct audit_entry *e;
1291         int ret = 1;
1292
1293         rcu_read_lock();
1294         list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1295                 if (audit_filter_user_rules(cb, &e->rule, &state)) {
1296                         if (state == AUDIT_DISABLED)
1297                                 ret = 0;
1298                         break;
1299                 }
1300         }
1301         rcu_read_unlock();
1302
1303         return ret; /* Audit by default */
1304 }
1305
1306 int audit_filter_type(int type)
1307 {
1308         struct audit_entry *e;
1309         int result = 0;
1310
1311         rcu_read_lock();
1312         if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1313                 goto unlock_and_return;
1314
1315         list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1316                                 list) {
1317                 int i;
1318                 for (i = 0; i < e->rule.field_count; i++) {
1319                         struct audit_field *f = &e->rule.fields[i];
1320                         if (f->type == AUDIT_MSGTYPE) {
1321                                 result = audit_comparator(type, f->op, f->val);
1322                                 if (!result)
1323                                         break;
1324                         }
1325                 }
1326                 if (result)
1327                         goto unlock_and_return;
1328         }
1329 unlock_and_return:
1330         rcu_read_unlock();
1331         return result;
1332 }
1333
1334 static int update_lsm_rule(struct audit_krule *r)
1335 {
1336         struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1337         struct audit_entry *nentry;
1338         int err = 0;
1339
1340         if (!security_audit_rule_known(r))
1341                 return 0;
1342
1343         nentry = audit_dupe_rule(r);
1344         if (IS_ERR(nentry)) {
1345                 /* save the first error encountered for the
1346                  * return value */
1347                 err = PTR_ERR(nentry);
1348                 audit_panic("error updating LSM filters");
1349                 if (r->watch)
1350                         list_del(&r->rlist);
1351                 list_del_rcu(&entry->list);
1352                 list_del(&r->list);
1353         } else {
1354                 if (r->watch || r->tree)
1355                         list_replace_init(&r->rlist, &nentry->rule.rlist);
1356                 list_replace_rcu(&entry->list, &nentry->list);
1357                 list_replace(&r->list, &nentry->rule.list);
1358         }
1359         call_rcu(&entry->rcu, audit_free_rule_rcu);
1360
1361         return err;
1362 }
1363
1364 /* This function will re-initialize the lsm_rule field of all applicable rules.
1365  * It will traverse the filter lists serarching for rules that contain LSM
1366  * specific filter fields.  When such a rule is found, it is copied, the
1367  * LSM field is re-initialized, and the old rule is replaced with the
1368  * updated rule. */
1369 int audit_update_lsm_rules(void)
1370 {
1371         struct audit_krule *r, *n;
1372         int i, err = 0;
1373
1374         /* audit_filter_mutex synchronizes the writers */
1375         mutex_lock(&audit_filter_mutex);
1376
1377         for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1378                 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1379                         int res = update_lsm_rule(r);
1380                         if (!err)
1381                                 err = res;
1382                 }
1383         }
1384         mutex_unlock(&audit_filter_mutex);
1385
1386         return err;
1387 }