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                 f->uid = INVALID_UID;
 346                 f->gid = INVALID_GID;
 347
 348                 err = -EINVAL;
 349                 if (f->op == Audit_bad)
 350                         goto exit_free;
 351
 352                 switch(f->type) {
 353                 default:
 354                         goto exit_free;
 355                 case AUDIT_UID:
 356                 case AUDIT_EUID:
 357                 case AUDIT_SUID:
 358                 case AUDIT_FSUID:
 359                 case AUDIT_LOGINUID:
 360                         /* bit ops not implemented for uid comparisons */
 361                         if (f->op == Audit_bitmask || f->op == Audit_bittest)
 362                                 goto exit_free;
 363
 364                         f->uid = make_kuid(current_user_ns(), f->val);
 365                         if (!uid_valid(f->uid))
 366                                 goto exit_free;
 367                         break;
 368                 case AUDIT_GID:
 369                 case AUDIT_EGID:
 370                 case AUDIT_SGID:
 371                 case AUDIT_FSGID:
 372                         /* bit ops not implemented for gid comparisons */
 373                         if (f->op == Audit_bitmask || f->op == Audit_bittest)
 374                                 goto exit_free;
 375
 376                         f->gid = make_kgid(current_user_ns(), f->val);
 377                         if (!gid_valid(f->gid))
 378                                 goto exit_free;
 379                         break;
 380                 case AUDIT_PID:
 381                 case AUDIT_PERS:
 382                 case AUDIT_MSGTYPE:
 383                 case AUDIT_PPID:
 384                 case AUDIT_DEVMAJOR:
 385                 case AUDIT_DEVMINOR:
 386                 case AUDIT_EXIT:
 387                 case AUDIT_SUCCESS:
 388                         /* bit ops are only useful on syscall args */
 389                         if (f->op == Audit_bitmask || f->op == Audit_bittest)
 390                                 goto exit_free;
 391                         break;
 392                 case AUDIT_ARG0:
 393                 case AUDIT_ARG1:
 394                 case AUDIT_ARG2:
 395                 case AUDIT_ARG3:
 396                         break;
 397                 /* arch is only allowed to be = or != */
 398                 case AUDIT_ARCH:
 399                         if (f->op != Audit_not_equal && f->op != Audit_equal)
 400                                 goto exit_free;
 401                         entry->rule.arch_f = f;
 402                         break;
 403                 case AUDIT_PERM:
 404                         if (f->val & ~15)
 405                                 goto exit_free;
 406                         break;
 407                 case AUDIT_FILETYPE:
 408                         if (f->val & ~S_IFMT)
 409                                 goto exit_free;
 410                         break;
 411                 case AUDIT_INODE:
 412                         err = audit_to_inode(&entry->rule, f);
 413                         if (err)
 414                                 goto exit_free;
 415                         break;
 416                 }
 417         }
 418
 419         if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
 420                 entry->rule.inode_f = NULL;
 421
 422 exit_nofree:
 423         return entry;
 424
 425 exit_free:
 426         audit_free_rule(entry);
 427         return ERR_PTR(err);
 428 }
 429
 430 /* Translate struct audit_rule_data to kernel's rule respresentation. */
 431 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
 432                                                size_t datasz)
 433 {
 434         int err = 0;
 435         struct audit_entry *entry;
 436         void *bufp;
 437         size_t remain = datasz - sizeof(struct audit_rule_data);
 438         int i;
 439         char *str;
 440
 441         entry = audit_to_entry_common((struct audit_rule *)data);
 442         if (IS_ERR(entry))
 443                 goto exit_nofree;
 444
 445         bufp = data->buf;
 446         entry->rule.vers_ops = 2;
 447         for (i = 0; i < data->field_count; i++) {
 448                 struct audit_field *f = &entry->rule.fields[i];
 449
 450                 err = -EINVAL;
 451
 452                 f->op = audit_to_op(data->fieldflags[i]);
 453                 if (f->op == Audit_bad)
 454                         goto exit_free;
 455
 456                 f->type = data->fields[i];
 457                 f->val = data->values[i];
 458                 f->uid = INVALID_UID;
 459                 f->gid = INVALID_GID;
 460                 f->lsm_str = NULL;
 461                 f->lsm_rule = NULL;
 462                 switch(f->type) {
 463                 case AUDIT_UID:
 464                 case AUDIT_EUID:
 465                 case AUDIT_SUID:
 466                 case AUDIT_FSUID:
 467                 case AUDIT_LOGINUID:
 468                 case AUDIT_OBJ_UID:
 469                         /* bit ops not implemented for uid comparisons */
 470                         if (f->op == Audit_bitmask || f->op == Audit_bittest)
 471                                 goto exit_free;
 472
 473                         f->uid = make_kuid(current_user_ns(), f->val);
 474                         if (!uid_valid(f->uid))
 475                                 goto exit_free;
 476                         break;
 477                 case AUDIT_GID:
 478                 case AUDIT_EGID:
 479                 case AUDIT_SGID:
 480                 case AUDIT_FSGID:
 481                 case AUDIT_OBJ_GID:
 482                         /* bit ops not implemented for gid comparisons */
 483                         if (f->op == Audit_bitmask || f->op == Audit_bittest)
 484                                 goto exit_free;
 485
 486                         f->gid = make_kgid(current_user_ns(), f->val);
 487                         if (!gid_valid(f->gid))
 488                                 goto exit_free;
 489                         break;
 490                 case AUDIT_PID:
 491                 case AUDIT_PERS:
 492                 case AUDIT_MSGTYPE:
 493                 case AUDIT_PPID:
 494                 case AUDIT_DEVMAJOR:
 495                 case AUDIT_DEVMINOR:
 496                 case AUDIT_EXIT:
 497                 case AUDIT_SUCCESS:
 498                 case AUDIT_ARG0:
 499                 case AUDIT_ARG1:
 500                 case AUDIT_ARG2:
 501                 case AUDIT_ARG3:
 502                         break;
 503                 case AUDIT_ARCH:
 504                         entry->rule.arch_f = f;
 505                         break;
 506                 case AUDIT_SUBJ_USER:
 507                 case AUDIT_SUBJ_ROLE:
 508                 case AUDIT_SUBJ_TYPE:
 509                 case AUDIT_SUBJ_SEN:
 510                 case AUDIT_SUBJ_CLR:
 511                 case AUDIT_OBJ_USER:
 512                 case AUDIT_OBJ_ROLE:
 513                 case AUDIT_OBJ_TYPE:
 514                 case AUDIT_OBJ_LEV_LOW:
 515                 case AUDIT_OBJ_LEV_HIGH:
 516                         str = audit_unpack_string(&bufp, &remain, f->val);
 517                         if (IS_ERR(str))
 518                                 goto exit_free;
 519                         entry->rule.buflen += f->val;
 520
 521                         err = security_audit_rule_init(f->type, f->op, str,
 522                                                        (void **)&f->lsm_rule);
 523                         /* Keep currently invalid fields around in case they
 524                          * become valid after a policy reload. */
 525                         if (err == -EINVAL) {
 526                                 printk(KERN_WARNING "audit rule for LSM "
 527                                        "\'%s\' is invalid\n",  str);
 528                                 err = 0;
 529                         }
 530                         if (err) {
 531                                 kfree(str);
 532                                 goto exit_free;
 533                         } else
 534                                 f->lsm_str = str;
 535                         break;
 536                 case AUDIT_WATCH:
 537                         str = audit_unpack_string(&bufp, &remain, f->val);
 538                         if (IS_ERR(str))
 539                                 goto exit_free;
 540                         entry->rule.buflen += f->val;
 541
 542                         err = audit_to_watch(&entry->rule, str, f->val, f->op);
 543                         if (err) {
 544                                 kfree(str);
 545                                 goto exit_free;
 546                         }
 547                         break;
 548                 case AUDIT_DIR:
 549                         str = audit_unpack_string(&bufp, &remain, f->val);
 550                         if (IS_ERR(str))
 551                                 goto exit_free;
 552                         entry->rule.buflen += f->val;
 553
 554                         err = audit_make_tree(&entry->rule, str, f->op);
 555                         kfree(str);
 556                         if (err)
 557                                 goto exit_free;
 558                         break;
 559                 case AUDIT_INODE:
 560                         err = audit_to_inode(&entry->rule, f);
 561                         if (err)
 562                                 goto exit_free;
 563                         break;
 564                 case AUDIT_FILTERKEY:
 565                         if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
 566                                 goto exit_free;
 567                         str = audit_unpack_string(&bufp, &remain, f->val);
 568                         if (IS_ERR(str))
 569                                 goto exit_free;
 570                         entry->rule.buflen += f->val;
 571                         entry->rule.filterkey = str;
 572                         break;
 573                 case AUDIT_PERM:
 574                         if (f->val & ~15)
 575                                 goto exit_free;
 576                         break;
 577                 case AUDIT_FILETYPE:
 578                         if (f->val & ~S_IFMT)
 579                                 goto exit_free;
 580                         break;
 581                 case AUDIT_FIELD_COMPARE:
 582                         if (f->val > AUDIT_MAX_FIELD_COMPARE)
 583                                 goto exit_free;
 584                         break;
 585                 default:
 586                         goto exit_free;
 587                 }
 588         }
 589
 590         if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
 591                 entry->rule.inode_f = NULL;
 592
 593 exit_nofree:
 594         return entry;
 595
 596 exit_free:
 597         audit_free_rule(entry);
 598         return ERR_PTR(err);
 599 }
 600
 601 /* Pack a filter field's string representation into data block. */
 602 static inline size_t audit_pack_string(void **bufp, const char *str)
 603 {
 604         size_t len = strlen(str);
 605
 606         memcpy(*bufp, str, len);
 607         *bufp += len;
 608
 609         return len;
 610 }
 611
 612 /* Translate kernel rule respresentation to struct audit_rule.
 613  * Exists for backward compatibility with userspace. */
 614 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
 615 {
 616         struct audit_rule *rule;
 617         int i;
 618
 619         rule = kzalloc(sizeof(*rule), GFP_KERNEL);
 620         if (unlikely(!rule))
 621                 return NULL;
 622
 623         rule->flags = krule->flags | krule->listnr;
 624         rule->action = krule->action;
 625         rule->field_count = krule->field_count;
 626         for (i = 0; i < rule->field_count; i++) {
 627                 rule->values[i] = krule->fields[i].val;
 628                 rule->fields[i] = krule->fields[i].type;
 629
 630                 if (krule->vers_ops == 1) {
 631                         if (krule->fields[i].op == Audit_not_equal)
 632                                 rule->fields[i] |= AUDIT_NEGATE;
 633                 } else {
 634                         rule->fields[i] |= audit_ops[krule->fields[i].op];
 635                 }
 636         }
 637         for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
 638
 639         return rule;
 640 }
 641
 642 /* Translate kernel rule respresentation to struct audit_rule_data. */
 643 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
 644 {
 645         struct audit_rule_data *data;
 646         void *bufp;
 647         int i;
 648
 649         data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
 650         if (unlikely(!data))
 651                 return NULL;
 652         memset(data, 0, sizeof(*data));
 653
 654         data->flags = krule->flags | krule->listnr;
 655         data->action = krule->action;
 656         data->field_count = krule->field_count;
 657         bufp = data->buf;
 658         for (i = 0; i < data->field_count; i++) {
 659                 struct audit_field *f = &krule->fields[i];
 660
 661                 data->fields[i] = f->type;
 662                 data->fieldflags[i] = audit_ops[f->op];
 663                 switch(f->type) {
 664                 case AUDIT_SUBJ_USER:
 665                 case AUDIT_SUBJ_ROLE:
 666                 case AUDIT_SUBJ_TYPE:
 667                 case AUDIT_SUBJ_SEN:
 668                 case AUDIT_SUBJ_CLR:
 669                 case AUDIT_OBJ_USER:
 670                 case AUDIT_OBJ_ROLE:
 671                 case AUDIT_OBJ_TYPE:
 672                 case AUDIT_OBJ_LEV_LOW:
 673                 case AUDIT_OBJ_LEV_HIGH:
 674                         data->buflen += data->values[i] =
 675                                 audit_pack_string(&bufp, f->lsm_str);
 676                         break;
 677                 case AUDIT_WATCH:
 678                         data->buflen += data->values[i] =
 679                                 audit_pack_string(&bufp,
 680                                                   audit_watch_path(krule->watch));
 681                         break;
 682                 case AUDIT_DIR:
 683                         data->buflen += data->values[i] =
 684                                 audit_pack_string(&bufp,
 685                                                   audit_tree_path(krule->tree));
 686                         break;
 687                 case AUDIT_FILTERKEY:
 688                         data->buflen += data->values[i] =
 689                                 audit_pack_string(&bufp, krule->filterkey);
 690                         break;
 691                 default:
 692                         data->values[i] = f->val;
 693                 }
 694         }
 695         for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
 696
 697         return data;
 698 }
 699
 700 /* Compare two rules in kernel format.  Considered success if rules
 701  * don't match. */
 702 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
 703 {
 704         int i;
 705
 706         if (a->flags != b->flags ||
 707             a->listnr != b->listnr ||
 708             a->action != b->action ||
 709             a->field_count != b->field_count)
 710                 return 1;
 711
 712         for (i = 0; i < a->field_count; i++) {
 713                 if (a->fields[i].type != b->fields[i].type ||
 714                     a->fields[i].op != b->fields[i].op)
 715                         return 1;
 716
 717                 switch(a->fields[i].type) {
 718                 case AUDIT_SUBJ_USER:
 719                 case AUDIT_SUBJ_ROLE:
 720                 case AUDIT_SUBJ_TYPE:
 721                 case AUDIT_SUBJ_SEN:
 722                 case AUDIT_SUBJ_CLR:
 723                 case AUDIT_OBJ_USER:
 724                 case AUDIT_OBJ_ROLE:
 725                 case AUDIT_OBJ_TYPE:
 726                 case AUDIT_OBJ_LEV_LOW:
 727                 case AUDIT_OBJ_LEV_HIGH:
 728                         if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
 729                                 return 1;
 730                         break;
 731                 case AUDIT_WATCH:
 732                         if (strcmp(audit_watch_path(a->watch),
 733                                    audit_watch_path(b->watch)))
 734                                 return 1;
 735                         break;
 736                 case AUDIT_DIR:
 737                         if (strcmp(audit_tree_path(a->tree),
 738                                    audit_tree_path(b->tree)))
 739                                 return 1;
 740                         break;
 741                 case AUDIT_FILTERKEY:
 742                         /* both filterkeys exist based on above type compare */
 743                         if (strcmp(a->filterkey, b->filterkey))
 744                                 return 1;
 745                         break;
 746                 case AUDIT_UID:
 747                 case AUDIT_EUID:
 748                 case AUDIT_SUID:
 749                 case AUDIT_FSUID:
 750                 case AUDIT_LOGINUID:
 751                 case AUDIT_OBJ_UID:
 752                         if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
 753                                 return 1;
 754                         break;
 755                 case AUDIT_GID:
 756                 case AUDIT_EGID:
 757                 case AUDIT_SGID:
 758                 case AUDIT_FSGID:
 759                 case AUDIT_OBJ_GID:
 760                         if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
 761                                 return 1;
 762                         break;
 763                 default:
 764                         if (a->fields[i].val != b->fields[i].val)
 765                                 return 1;
 766                 }
 767         }
 768
 769         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 770                 if (a->mask[i] != b->mask[i])
 771                         return 1;
 772
 773         return 0;
 774 }
 775
 776 /* Duplicate LSM field information.  The lsm_rule is opaque, so must be
 777  * re-initialized. */
 778 static inline int audit_dupe_lsm_field(struct audit_field *df,
 779                                            struct audit_field *sf)
 780 {
 781         int ret = 0;
 782         char *lsm_str;
 783
 784         /* our own copy of lsm_str */
 785         lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
 786         if (unlikely(!lsm_str))
 787                 return -ENOMEM;
 788         df->lsm_str = lsm_str;
 789
 790         /* our own (refreshed) copy of lsm_rule */
 791         ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
 792                                        (void **)&df->lsm_rule);
 793         /* Keep currently invalid fields around in case they
 794          * become valid after a policy reload. */
 795         if (ret == -EINVAL) {
 796                 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
 797                        "invalid\n", df->lsm_str);
 798                 ret = 0;
 799         }
 800
 801         return ret;
 802 }
 803
 804 /* Duplicate an audit rule.  This will be a deep copy with the exception
 805  * of the watch - that pointer is carried over.  The LSM specific fields
 806  * will be updated in the copy.  The point is to be able to replace the old
 807  * rule with the new rule in the filterlist, then free the old rule.
 808  * The rlist element is undefined; list manipulations are handled apart from
 809  * the initial copy. */
 810 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
 811 {
 812         u32 fcount = old->field_count;
 813         struct audit_entry *entry;
 814         struct audit_krule *new;
 815         char *fk;
 816         int i, err = 0;
 817
 818         entry = audit_init_entry(fcount);
 819         if (unlikely(!entry))
 820                 return ERR_PTR(-ENOMEM);
 821
 822         new = &entry->rule;
 823         new->vers_ops = old->vers_ops;
 824         new->flags = old->flags;
 825         new->listnr = old->listnr;
 826         new->action = old->action;
 827         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 828                 new->mask[i] = old->mask[i];
 829         new->prio = old->prio;
 830         new->buflen = old->buflen;
 831         new->inode_f = old->inode_f;
 832         new->field_count = old->field_count;
 833
 834         /*
 835          * note that we are OK with not refcounting here; audit_match_tree()
 836          * never dereferences tree and we can't get false positives there
 837          * since we'd have to have rule gone from the list *and* removed
 838          * before the chunks found by lookup had been allocated, i.e. before
 839          * the beginning of list scan.
 840          */
 841         new->tree = old->tree;
 842         memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
 843
 844         /* deep copy this information, updating the lsm_rule fields, because
 845          * the originals will all be freed when the old rule is freed. */
 846         for (i = 0; i < fcount; i++) {
 847                 switch (new->fields[i].type) {
 848                 case AUDIT_SUBJ_USER:
 849                 case AUDIT_SUBJ_ROLE:
 850                 case AUDIT_SUBJ_TYPE:
 851                 case AUDIT_SUBJ_SEN:
 852                 case AUDIT_SUBJ_CLR:
 853                 case AUDIT_OBJ_USER:
 854                 case AUDIT_OBJ_ROLE:
 855                 case AUDIT_OBJ_TYPE:
 856                 case AUDIT_OBJ_LEV_LOW:
 857                 case AUDIT_OBJ_LEV_HIGH:
 858                         err = audit_dupe_lsm_field(&new->fields[i],
 859                                                        &old->fields[i]);
 860                         break;
 861                 case AUDIT_FILTERKEY:
 862                         fk = kstrdup(old->filterkey, GFP_KERNEL);
 863                         if (unlikely(!fk))
 864                                 err = -ENOMEM;
 865                         else
 866                                 new->filterkey = fk;
 867                 }
 868                 if (err) {
 869                         audit_free_rule(entry);
 870                         return ERR_PTR(err);
 871                 }
 872         }
 873
 874         if (old->watch) {
 875                 audit_get_watch(old->watch);
 876                 new->watch = old->watch;
 877         }
 878
 879         return entry;
 880 }
 881
 882 /* Find an existing audit rule.
 883  * Caller must hold audit_filter_mutex to prevent stale rule data. */
 884 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
 885                                            struct list_head **p)
 886 {
 887         struct audit_entry *e, *found = NULL;
 888         struct list_head *list;
 889         int h;
 890
 891         if (entry->rule.inode_f) {
 892                 h = audit_hash_ino(entry->rule.inode_f->val);
 893                 *p = list = &audit_inode_hash[h];
 894         } else if (entry->rule.watch) {
 895                 /* we don't know the inode number, so must walk entire hash */
 896                 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
 897                         list = &audit_inode_hash[h];
 898                         list_for_each_entry(e, list, list)
 899                                 if (!audit_compare_rule(&entry->rule, &e->rule)) {
 900                                         found = e;
 901                                         goto out;
 902                                 }
 903                 }
 904                 goto out;
 905         } else {
 906                 *p = list = &audit_filter_list[entry->rule.listnr];
 907         }
 908
 909         list_for_each_entry(e, list, list)
 910                 if (!audit_compare_rule(&entry->rule, &e->rule)) {
 911                         found = e;
 912                         goto out;
 913                 }
 914
 915 out:
 916         return found;
 917 }
 918
 919 static u64 prio_low = ~0ULL/2;
 920 static u64 prio_high = ~0ULL/2 - 1;
 921
 922 /* Add rule to given filterlist if not a duplicate. */
 923 static inline int audit_add_rule(struct audit_entry *entry)
 924 {
 925         struct audit_entry *e;
 926         struct audit_watch *watch = entry->rule.watch;
 927         struct audit_tree *tree = entry->rule.tree;
 928         struct list_head *list;
 929         int err;
 930 #ifdef CONFIG_AUDITSYSCALL
 931         int dont_count = 0;
 932
 933         /* If either of these, don't count towards total */
 934         if (entry->rule.listnr == AUDIT_FILTER_USER ||
 935                 entry->rule.listnr == AUDIT_FILTER_TYPE)
 936                 dont_count = 1;
 937 #endif
 938
 939         mutex_lock(&audit_filter_mutex);
 940         e = audit_find_rule(entry, &list);
 941         if (e) {
 942                 mutex_unlock(&audit_filter_mutex);
 943                 err = -EEXIST;
 944                 /* normally audit_add_tree_rule() will free it on failure */
 945                 if (tree)
 946                         audit_put_tree(tree);
 947                 goto error;
 948         }
 949
 950         if (watch) {
 951                 /* audit_filter_mutex is dropped and re-taken during this call */
 952                 err = audit_add_watch(&entry->rule, &list);
 953                 if (err) {
 954                         mutex_unlock(&audit_filter_mutex);
 955                         goto error;
 956                 }
 957         }
 958         if (tree) {
 959                 err = audit_add_tree_rule(&entry->rule);
 960                 if (err) {
 961                         mutex_unlock(&audit_filter_mutex);
 962                         goto error;
 963                 }
 964         }
 965
 966         entry->rule.prio = ~0ULL;
 967         if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
 968                 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
 969                         entry->rule.prio = ++prio_high;
 970                 else
 971                         entry->rule.prio = --prio_low;
 972         }
 973
 974         if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
 975                 list_add(&entry->rule.list,
 976                          &audit_rules_list[entry->rule.listnr]);
 977                 list_add_rcu(&entry->list, list);
 978                 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
 979         } else {
 980                 list_add_tail(&entry->rule.list,
 981                               &audit_rules_list[entry->rule.listnr]);
 982                 list_add_tail_rcu(&entry->list, list);
 983         }
 984 #ifdef CONFIG_AUDITSYSCALL
 985         if (!dont_count)
 986                 audit_n_rules++;
 987
 988         if (!audit_match_signal(entry))
 989                 audit_signals++;
 990 #endif
 991         mutex_unlock(&audit_filter_mutex);
 992
 993         return 0;
 994
 995 error:
 996         if (watch)
 997                 audit_put_watch(watch); /* tmp watch, matches initial get */
 998         return err;
 999 }
1000
1001 /* Remove an existing rule from filterlist. */
1002 static inline int audit_del_rule(struct audit_entry *entry)
1003 {
1004         struct audit_entry  *e;
1005         struct audit_watch *watch = entry->rule.watch;
1006         struct audit_tree *tree = entry->rule.tree;
1007         struct list_head *list;
1008         int ret = 0;
1009 #ifdef CONFIG_AUDITSYSCALL
1010         int dont_count = 0;
1011
1012         /* If either of these, don't count towards total */
1013         if (entry->rule.listnr == AUDIT_FILTER_USER ||
1014                 entry->rule.listnr == AUDIT_FILTER_TYPE)
1015                 dont_count = 1;
1016 #endif
1017
1018         mutex_lock(&audit_filter_mutex);
1019         e = audit_find_rule(entry, &list);
1020         if (!e) {
1021                 mutex_unlock(&audit_filter_mutex);
1022                 ret = -ENOENT;
1023                 goto out;
1024         }
1025
1026         if (e->rule.watch)
1027                 audit_remove_watch_rule(&e->rule);
1028
1029         if (e->rule.tree)
1030                 audit_remove_tree_rule(&e->rule);
1031
1032         list_del_rcu(&e->list);
1033         list_del(&e->rule.list);
1034         call_rcu(&e->rcu, audit_free_rule_rcu);
1035
1036 #ifdef CONFIG_AUDITSYSCALL
1037         if (!dont_count)
1038                 audit_n_rules--;
1039
1040         if (!audit_match_signal(entry))
1041                 audit_signals--;
1042 #endif
1043         mutex_unlock(&audit_filter_mutex);
1044
1045 out:
1046         if (watch)
1047                 audit_put_watch(watch); /* match initial get */
1048         if (tree)
1049                 audit_put_tree(tree);   /* that's the temporary one */
1050
1051         return ret;
1052 }
1053
1054 /* List rules using struct audit_rule.  Exists for backward
1055  * compatibility with userspace. */
1056 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1057 {
1058         struct sk_buff *skb;
1059         struct audit_krule *r;
1060         int i;
1061
1062         /* This is a blocking read, so use audit_filter_mutex instead of rcu
1063          * iterator to sync with list writers. */
1064         for (i=0; i<AUDIT_NR_FILTERS; i++) {
1065                 list_for_each_entry(r, &audit_rules_list[i], list) {
1066                         struct audit_rule *rule;
1067
1068                         rule = audit_krule_to_rule(r);
1069                         if (unlikely(!rule))
1070                                 break;
1071                         skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1072                                          rule, sizeof(*rule));
1073                         if (skb)
1074                                 skb_queue_tail(q, skb);
1075                         kfree(rule);
1076                 }
1077         }
1078         skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1079         if (skb)
1080                 skb_queue_tail(q, skb);
1081 }
1082
1083 /* List rules using struct audit_rule_data. */
1084 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1085 {
1086         struct sk_buff *skb;
1087         struct audit_krule *r;
1088         int i;
1089
1090         /* This is a blocking read, so use audit_filter_mutex instead of rcu
1091          * iterator to sync with list writers. */
1092         for (i=0; i<AUDIT_NR_FILTERS; i++) {
1093                 list_for_each_entry(r, &audit_rules_list[i], list) {
1094                         struct audit_rule_data *data;
1095
1096                         data = audit_krule_to_data(r);
1097                         if (unlikely(!data))
1098                                 break;
1099                         skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1100                                          data, sizeof(*data) + data->buflen);
1101                         if (skb)
1102                                 skb_queue_tail(q, skb);
1103                         kfree(data);
1104                 }
1105         }
1106         skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1107         if (skb)
1108                 skb_queue_tail(q, skb);
1109 }
1110
1111 /* Log rule additions and removals */
1112 static void audit_log_rule_change(kuid_t loginuid, u32 sessionid, u32 sid,
1113                                   char *action, struct audit_krule *rule,
1114                                   int res)
1115 {
1116         struct audit_buffer *ab;
1117
1118         if (!audit_enabled)
1119                 return;
1120
1121         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1122         if (!ab)
1123                 return;
1124         audit_log_format(ab, "auid=%u ses=%u",
1125                          from_kuid(&init_user_ns, loginuid), sessionid);
1126         if (sid) {
1127                 char *ctx = NULL;
1128                 u32 len;
1129                 if (security_secid_to_secctx(sid, &ctx, &len))
1130                         audit_log_format(ab, " ssid=%u", sid);
1131                 else {
1132                         audit_log_format(ab, " subj=%s", ctx);
1133                         security_release_secctx(ctx, len);
1134                 }
1135         }
1136         audit_log_format(ab, " op=");
1137         audit_log_string(ab, action);
1138         audit_log_key(ab, rule->filterkey);
1139         audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1140         audit_log_end(ab);
1141 }
1142
1143 /**
1144  * audit_receive_filter - apply all rules to the specified message type
1145  * @type: audit message type
1146  * @pid: target pid for netlink audit messages
1147  * @uid: target uid for netlink audit messages
1148  * @seq: netlink audit message sequence (serial) number
1149  * @data: payload data
1150  * @datasz: size of payload data
1151  * @loginuid: loginuid of sender
1152  * @sessionid: sessionid for netlink audit message
1153  * @sid: SE Linux Security ID of sender
1154  */
1155 int audit_receive_filter(int type, int pid, int seq, void *data,
1156                          size_t datasz, kuid_t loginuid, u32 sessionid, u32 sid)
1157 {
1158         struct task_struct *tsk;
1159         struct audit_netlink_list *dest;
1160         int err = 0;
1161         struct audit_entry *entry;
1162
1163         switch (type) {
1164         case AUDIT_LIST:
1165         case AUDIT_LIST_RULES:
1166                 /* We can't just spew out the rules here because we might fill
1167                  * the available socket buffer space and deadlock waiting for
1168                  * auditctl to read from it... which isn't ever going to
1169                  * happen if we're actually running in the context of auditctl
1170                  * trying to _send_ the stuff */
1171
1172                 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1173                 if (!dest)
1174                         return -ENOMEM;
1175                 dest->pid = pid;
1176                 skb_queue_head_init(&dest->q);
1177
1178                 mutex_lock(&audit_filter_mutex);
1179                 if (type == AUDIT_LIST)
1180                         audit_list(pid, seq, &dest->q);
1181                 else
1182                         audit_list_rules(pid, seq, &dest->q);
1183                 mutex_unlock(&audit_filter_mutex);
1184
1185                 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1186                 if (IS_ERR(tsk)) {
1187                         skb_queue_purge(&dest->q);
1188                         kfree(dest);
1189                         err = PTR_ERR(tsk);
1190                 }
1191                 break;
1192         case AUDIT_ADD:
1193         case AUDIT_ADD_RULE:
1194                 if (type == AUDIT_ADD)
1195                         entry = audit_rule_to_entry(data);
1196                 else
1197                         entry = audit_data_to_entry(data, datasz);
1198                 if (IS_ERR(entry))
1199                         return PTR_ERR(entry);
1200
1201                 err = audit_add_rule(entry);
1202                 audit_log_rule_change(loginuid, sessionid, sid, "add rule",
1203                                       &entry->rule, !err);
1204
1205                 if (err)
1206                         audit_free_rule(entry);
1207                 break;
1208         case AUDIT_DEL:
1209         case AUDIT_DEL_RULE:
1210                 if (type == AUDIT_DEL)
1211                         entry = audit_rule_to_entry(data);
1212                 else
1213                         entry = audit_data_to_entry(data, datasz);
1214                 if (IS_ERR(entry))
1215                         return PTR_ERR(entry);
1216
1217                 err = audit_del_rule(entry);
1218                 audit_log_rule_change(loginuid, sessionid, sid, "remove rule",
1219                                       &entry->rule, !err);
1220
1221                 audit_free_rule(entry);
1222                 break;
1223         default:
1224                 return -EINVAL;
1225         }
1226
1227         return err;
1228 }
1229
1230 int audit_comparator(u32 left, u32 op, u32 right)
1231 {
1232         switch (op) {
1233         case Audit_equal:
1234                 return (left == right);
1235         case Audit_not_equal:
1236                 return (left != right);
1237         case Audit_lt:
1238                 return (left < right);
1239         case Audit_le:
1240                 return (left <= right);
1241         case Audit_gt:
1242                 return (left > right);
1243         case Audit_ge:
1244                 return (left >= right);
1245         case Audit_bitmask:
1246                 return (left & right);
1247         case Audit_bittest:
1248                 return ((left & right) == right);
1249         default:
1250                 BUG();
1251                 return 0;
1252         }
1253 }
1254
1255 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1256 {
1257         switch (op) {
1258         case Audit_equal:
1259                 return uid_eq(left, right);
1260         case Audit_not_equal:
1261                 return !uid_eq(left, right);
1262         case Audit_lt:
1263                 return uid_lt(left, right);
1264         case Audit_le:
1265                 return uid_lte(left, right);
1266         case Audit_gt:
1267                 return uid_gt(left, right);
1268         case Audit_ge:
1269                 return uid_gte(left, right);
1270         case Audit_bitmask:
1271         case Audit_bittest:
1272         default:
1273                 BUG();
1274                 return 0;
1275         }
1276 }
1277
1278 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1279 {
1280         switch (op) {
1281         case Audit_equal:
1282                 return gid_eq(left, right);
1283         case Audit_not_equal:
1284                 return !gid_eq(left, right);
1285         case Audit_lt:
1286                 return gid_lt(left, right);
1287         case Audit_le:
1288                 return gid_lte(left, right);
1289         case Audit_gt:
1290                 return gid_gt(left, right);
1291         case Audit_ge:
1292                 return gid_gte(left, right);
1293         case Audit_bitmask:
1294         case Audit_bittest:
1295         default:
1296                 BUG();
1297                 return 0;
1298         }
1299 }
1300
1301 /**
1302  * parent_len - find the length of the parent portion of a pathname
1303  * @path: pathname of which to determine length
1304  */
1305 int parent_len(const char *path)
1306 {
1307         int plen;
1308         const char *p;
1309
1310         plen = strlen(path);
1311
1312         if (plen == 0)
1313                 return plen;
1314
1315         /* disregard trailing slashes */
1316         p = path + plen - 1;
1317         while ((*p == '/') && (p > path))
1318                 p--;
1319
1320         /* walk backward until we find the next slash or hit beginning */
1321         while ((*p != '/') && (p > path))
1322                 p--;
1323
1324         /* did we find a slash? Then increment to include it in path */
1325         if (*p == '/')
1326                 p++;
1327
1328         return p - path;
1329 }
1330
1331 /**
1332  * audit_compare_dname_path - compare given dentry name with last component in
1333  *                            given path. Return of 0 indicates a match.
1334  * @dname:      dentry name that we're comparing
1335  * @path:       full pathname that we're comparing
1336  * @parentlen:  length of the parent if known. Passing in AUDIT_NAME_FULL
1337  *              here indicates that we must compute this value.
1338  */
1339 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1340 {
1341         int dlen, pathlen;
1342         const char *p;
1343
1344         dlen = strlen(dname);
1345         pathlen = strlen(path);
1346         if (pathlen < dlen)
1347                 return 1;
1348
1349         parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1350         if (pathlen - parentlen != dlen)
1351                 return 1;
1352
1353         p = path + parentlen;
1354
1355         return strncmp(p, dname, dlen);
1356 }
1357
1358 static int audit_filter_user_rules(struct audit_krule *rule,
1359                                    enum audit_state *state)
1360 {
1361         int i;
1362
1363         for (i = 0; i < rule->field_count; i++) {
1364                 struct audit_field *f = &rule->fields[i];
1365                 int result = 0;
1366                 u32 sid;
1367
1368                 switch (f->type) {
1369                 case AUDIT_PID:
1370                         result = audit_comparator(task_pid_vnr(current), f->op, f->val);
1371                         break;
1372                 case AUDIT_UID:
1373                         result = audit_uid_comparator(current_uid(), f->op, f->uid);
1374                         break;
1375                 case AUDIT_GID:
1376                         result = audit_gid_comparator(current_gid(), f->op, f->gid);
1377                         break;
1378                 case AUDIT_LOGINUID:
1379                         result = audit_uid_comparator(audit_get_loginuid(current),
1380                                                   f->op, f->uid);
1381                         break;
1382                 case AUDIT_SUBJ_USER:
1383                 case AUDIT_SUBJ_ROLE:
1384                 case AUDIT_SUBJ_TYPE:
1385                 case AUDIT_SUBJ_SEN:
1386                 case AUDIT_SUBJ_CLR:
1387                         if (f->lsm_rule) {
1388                                 security_task_getsecid(current, &sid);
1389                                 result = security_audit_rule_match(sid,
1390                                                                    f->type,
1391                                                                    f->op,
1392                                                                    f->lsm_rule,
1393                                                                    NULL);
1394                         }
1395                         break;
1396                 }
1397
1398                 if (!result)
1399                         return 0;
1400         }
1401         switch (rule->action) {
1402         case AUDIT_NEVER:    *state = AUDIT_DISABLED;       break;
1403         case AUDIT_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
1404         }
1405         return 1;
1406 }
1407
1408 int audit_filter_user(void)
1409 {
1410         enum audit_state state = AUDIT_DISABLED;
1411         struct audit_entry *e;
1412         int ret = 1;
1413
1414         rcu_read_lock();
1415         list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1416                 if (audit_filter_user_rules(&e->rule, &state)) {
1417                         if (state == AUDIT_DISABLED)
1418                                 ret = 0;
1419                         break;
1420                 }
1421         }
1422         rcu_read_unlock();
1423
1424         return ret; /* Audit by default */
1425 }
1426
1427 int audit_filter_type(int type)
1428 {
1429         struct audit_entry *e;
1430         int result = 0;
1431
1432         rcu_read_lock();
1433         if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1434                 goto unlock_and_return;
1435
1436         list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1437                                 list) {
1438                 int i;
1439                 for (i = 0; i < e->rule.field_count; i++) {
1440                         struct audit_field *f = &e->rule.fields[i];
1441                         if (f->type == AUDIT_MSGTYPE) {
1442                                 result = audit_comparator(type, f->op, f->val);
1443                                 if (!result)
1444                                         break;
1445                         }
1446                 }
1447                 if (result)
1448                         goto unlock_and_return;
1449         }
1450 unlock_and_return:
1451         rcu_read_unlock();
1452         return result;
1453 }
1454
1455 static int update_lsm_rule(struct audit_krule *r)
1456 {
1457         struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1458         struct audit_entry *nentry;
1459         int err = 0;
1460
1461         if (!security_audit_rule_known(r))
1462                 return 0;
1463
1464         nentry = audit_dupe_rule(r);
1465         if (IS_ERR(nentry)) {
1466                 /* save the first error encountered for the
1467                  * return value */
1468                 err = PTR_ERR(nentry);
1469                 audit_panic("error updating LSM filters");
1470                 if (r->watch)
1471                         list_del(&r->rlist);
1472                 list_del_rcu(&entry->list);
1473                 list_del(&r->list);
1474         } else {
1475                 if (r->watch || r->tree)
1476                         list_replace_init(&r->rlist, &nentry->rule.rlist);
1477                 list_replace_rcu(&entry->list, &nentry->list);
1478                 list_replace(&r->list, &nentry->rule.list);
1479         }
1480         call_rcu(&entry->rcu, audit_free_rule_rcu);
1481
1482         return err;
1483 }
1484
1485 /* This function will re-initialize the lsm_rule field of all applicable rules.
1486  * It will traverse the filter lists serarching for rules that contain LSM
1487  * specific filter fields.  When such a rule is found, it is copied, the
1488  * LSM field is re-initialized, and the old rule is replaced with the
1489  * updated rule. */
1490 int audit_update_lsm_rules(void)
1491 {
1492         struct audit_krule *r, *n;
1493         int i, err = 0;
1494
1495         /* audit_filter_mutex synchronizes the writers */
1496         mutex_lock(&audit_filter_mutex);
1497
1498         for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1499                 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1500                         int res = update_lsm_rule(r);
1501                         if (!err)
1502                                 err = res;
1503                 }
1504         }
1505         mutex_unlock(&audit_filter_mutex);
1506
1507         return err;
1508 }