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