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         if (entry->rule.watch)
 598                 audit_put_watch(entry->rule.watch); /* matches initial get */
 599         if (entry->rule.tree)
 600                 audit_put_tree(entry->rule.tree); /* that's the temporary one */
 601         audit_free_rule(entry);
 602         return ERR_PTR(err);
 603 }
 604
 605 /* Pack a filter field's string representation into data block. */
 606 static inline size_t audit_pack_string(void **bufp, const char *str)
 607 {
 608         size_t len = strlen(str);
 609
 610         memcpy(*bufp, str, len);
 611         *bufp += len;
 612
 613         return len;
 614 }
 615
 616 /* Translate kernel rule respresentation to struct audit_rule.
 617  * Exists for backward compatibility with userspace. */
 618 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
 619 {
 620         struct audit_rule *rule;
 621         int i;
 622
 623         rule = kzalloc(sizeof(*rule), GFP_KERNEL);
 624         if (unlikely(!rule))
 625                 return NULL;
 626
 627         rule->flags = krule->flags | krule->listnr;
 628         rule->action = krule->action;
 629         rule->field_count = krule->field_count;
 630         for (i = 0; i < rule->field_count; i++) {
 631                 rule->values[i] = krule->fields[i].val;
 632                 rule->fields[i] = krule->fields[i].type;
 633
 634                 if (krule->vers_ops == 1) {
 635                         if (krule->fields[i].op == Audit_not_equal)
 636                                 rule->fields[i] |= AUDIT_NEGATE;
 637                 } else {
 638                         rule->fields[i] |= audit_ops[krule->fields[i].op];
 639                 }
 640         }
 641         for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
 642
 643         return rule;
 644 }
 645
 646 /* Translate kernel rule respresentation to struct audit_rule_data. */
 647 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
 648 {
 649         struct audit_rule_data *data;
 650         void *bufp;
 651         int i;
 652
 653         data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
 654         if (unlikely(!data))
 655                 return NULL;
 656         memset(data, 0, sizeof(*data));
 657
 658         data->flags = krule->flags | krule->listnr;
 659         data->action = krule->action;
 660         data->field_count = krule->field_count;
 661         bufp = data->buf;
 662         for (i = 0; i < data->field_count; i++) {
 663                 struct audit_field *f = &krule->fields[i];
 664
 665                 data->fields[i] = f->type;
 666                 data->fieldflags[i] = audit_ops[f->op];
 667                 switch(f->type) {
 668                 case AUDIT_SUBJ_USER:
 669                 case AUDIT_SUBJ_ROLE:
 670                 case AUDIT_SUBJ_TYPE:
 671                 case AUDIT_SUBJ_SEN:
 672                 case AUDIT_SUBJ_CLR:
 673                 case AUDIT_OBJ_USER:
 674                 case AUDIT_OBJ_ROLE:
 675                 case AUDIT_OBJ_TYPE:
 676                 case AUDIT_OBJ_LEV_LOW:
 677                 case AUDIT_OBJ_LEV_HIGH:
 678                         data->buflen += data->values[i] =
 679                                 audit_pack_string(&bufp, f->lsm_str);
 680                         break;
 681                 case AUDIT_WATCH:
 682                         data->buflen += data->values[i] =
 683                                 audit_pack_string(&bufp,
 684                                                   audit_watch_path(krule->watch));
 685                         break;
 686                 case AUDIT_DIR:
 687                         data->buflen += data->values[i] =
 688                                 audit_pack_string(&bufp,
 689                                                   audit_tree_path(krule->tree));
 690                         break;
 691                 case AUDIT_FILTERKEY:
 692                         data->buflen += data->values[i] =
 693                                 audit_pack_string(&bufp, krule->filterkey);
 694                         break;
 695                 default:
 696                         data->values[i] = f->val;
 697                 }
 698         }
 699         for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
 700
 701         return data;
 702 }
 703
 704 /* Compare two rules in kernel format.  Considered success if rules
 705  * don't match. */
 706 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
 707 {
 708         int i;
 709
 710         if (a->flags != b->flags ||
 711             a->listnr != b->listnr ||
 712             a->action != b->action ||
 713             a->field_count != b->field_count)
 714                 return 1;
 715
 716         for (i = 0; i < a->field_count; i++) {
 717                 if (a->fields[i].type != b->fields[i].type ||
 718                     a->fields[i].op != b->fields[i].op)
 719                         return 1;
 720
 721                 switch(a->fields[i].type) {
 722                 case AUDIT_SUBJ_USER:
 723                 case AUDIT_SUBJ_ROLE:
 724                 case AUDIT_SUBJ_TYPE:
 725                 case AUDIT_SUBJ_SEN:
 726                 case AUDIT_SUBJ_CLR:
 727                 case AUDIT_OBJ_USER:
 728                 case AUDIT_OBJ_ROLE:
 729                 case AUDIT_OBJ_TYPE:
 730                 case AUDIT_OBJ_LEV_LOW:
 731                 case AUDIT_OBJ_LEV_HIGH:
 732                         if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
 733                                 return 1;
 734                         break;
 735                 case AUDIT_WATCH:
 736                         if (strcmp(audit_watch_path(a->watch),
 737                                    audit_watch_path(b->watch)))
 738                                 return 1;
 739                         break;
 740                 case AUDIT_DIR:
 741                         if (strcmp(audit_tree_path(a->tree),
 742                                    audit_tree_path(b->tree)))
 743                                 return 1;
 744                         break;
 745                 case AUDIT_FILTERKEY:
 746                         /* both filterkeys exist based on above type compare */
 747                         if (strcmp(a->filterkey, b->filterkey))
 748                                 return 1;
 749                         break;
 750                 case AUDIT_UID:
 751                 case AUDIT_EUID:
 752                 case AUDIT_SUID:
 753                 case AUDIT_FSUID:
 754                 case AUDIT_LOGINUID:
 755                 case AUDIT_OBJ_UID:
 756                         if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
 757                                 return 1;
 758                         break;
 759                 case AUDIT_GID:
 760                 case AUDIT_EGID:
 761                 case AUDIT_SGID:
 762                 case AUDIT_FSGID:
 763                 case AUDIT_OBJ_GID:
 764                         if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
 765                                 return 1;
 766                         break;
 767                 default:
 768                         if (a->fields[i].val != b->fields[i].val)
 769                                 return 1;
 770                 }
 771         }
 772
 773         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 774                 if (a->mask[i] != b->mask[i])
 775                         return 1;
 776
 777         return 0;
 778 }
 779
 780 /* Duplicate LSM field information.  The lsm_rule is opaque, so must be
 781  * re-initialized. */
 782 static inline int audit_dupe_lsm_field(struct audit_field *df,
 783                                            struct audit_field *sf)
 784 {
 785         int ret = 0;
 786         char *lsm_str;
 787
 788         /* our own copy of lsm_str */
 789         lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
 790         if (unlikely(!lsm_str))
 791                 return -ENOMEM;
 792         df->lsm_str = lsm_str;
 793
 794         /* our own (refreshed) copy of lsm_rule */
 795         ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
 796                                        (void **)&df->lsm_rule);
 797         /* Keep currently invalid fields around in case they
 798          * become valid after a policy reload. */
 799         if (ret == -EINVAL) {
 800                 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
 801                        "invalid\n", df->lsm_str);
 802                 ret = 0;
 803         }
 804
 805         return ret;
 806 }
 807
 808 /* Duplicate an audit rule.  This will be a deep copy with the exception
 809  * of the watch - that pointer is carried over.  The LSM specific fields
 810  * will be updated in the copy.  The point is to be able to replace the old
 811  * rule with the new rule in the filterlist, then free the old rule.
 812  * The rlist element is undefined; list manipulations are handled apart from
 813  * the initial copy. */
 814 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
 815 {
 816         u32 fcount = old->field_count;
 817         struct audit_entry *entry;
 818         struct audit_krule *new;
 819         char *fk;
 820         int i, err = 0;
 821
 822         entry = audit_init_entry(fcount);
 823         if (unlikely(!entry))
 824                 return ERR_PTR(-ENOMEM);
 825
 826         new = &entry->rule;
 827         new->vers_ops = old->vers_ops;
 828         new->flags = old->flags;
 829         new->listnr = old->listnr;
 830         new->action = old->action;
 831         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 832                 new->mask[i] = old->mask[i];
 833         new->prio = old->prio;
 834         new->buflen = old->buflen;
 835         new->inode_f = old->inode_f;
 836         new->field_count = old->field_count;
 837
 838         /*
 839          * note that we are OK with not refcounting here; audit_match_tree()
 840          * never dereferences tree and we can't get false positives there
 841          * since we'd have to have rule gone from the list *and* removed
 842          * before the chunks found by lookup had been allocated, i.e. before
 843          * the beginning of list scan.
 844          */
 845         new->tree = old->tree;
 846         memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
 847
 848         /* deep copy this information, updating the lsm_rule fields, because
 849          * the originals will all be freed when the old rule is freed. */
 850         for (i = 0; i < fcount; i++) {
 851                 switch (new->fields[i].type) {
 852                 case AUDIT_SUBJ_USER:
 853                 case AUDIT_SUBJ_ROLE:
 854                 case AUDIT_SUBJ_TYPE:
 855                 case AUDIT_SUBJ_SEN:
 856                 case AUDIT_SUBJ_CLR:
 857                 case AUDIT_OBJ_USER:
 858                 case AUDIT_OBJ_ROLE:
 859                 case AUDIT_OBJ_TYPE:
 860                 case AUDIT_OBJ_LEV_LOW:
 861                 case AUDIT_OBJ_LEV_HIGH:
 862                         err = audit_dupe_lsm_field(&new->fields[i],
 863                                                        &old->fields[i]);
 864                         break;
 865                 case AUDIT_FILTERKEY:
 866                         fk = kstrdup(old->filterkey, GFP_KERNEL);
 867                         if (unlikely(!fk))
 868                                 err = -ENOMEM;
 869                         else
 870                                 new->filterkey = fk;
 871                 }
 872                 if (err) {
 873                         audit_free_rule(entry);
 874                         return ERR_PTR(err);
 875                 }
 876         }
 877
 878         if (old->watch) {
 879                 audit_get_watch(old->watch);
 880                 new->watch = old->watch;
 881         }
 882
 883         return entry;
 884 }
 885
 886 /* Find an existing audit rule.
 887  * Caller must hold audit_filter_mutex to prevent stale rule data. */
 888 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
 889                                            struct list_head **p)
 890 {
 891         struct audit_entry *e, *found = NULL;
 892         struct list_head *list;
 893         int h;
 894
 895         if (entry->rule.inode_f) {
 896                 h = audit_hash_ino(entry->rule.inode_f->val);
 897                 *p = list = &audit_inode_hash[h];
 898         } else if (entry->rule.watch) {
 899                 /* we don't know the inode number, so must walk entire hash */
 900                 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
 901                         list = &audit_inode_hash[h];
 902                         list_for_each_entry(e, list, list)
 903                                 if (!audit_compare_rule(&entry->rule, &e->rule)) {
 904                                         found = e;
 905                                         goto out;
 906                                 }
 907                 }
 908                 goto out;
 909         } else {
 910                 *p = list = &audit_filter_list[entry->rule.listnr];
 911         }
 912
 913         list_for_each_entry(e, list, list)
 914                 if (!audit_compare_rule(&entry->rule, &e->rule)) {
 915                         found = e;
 916                         goto out;
 917                 }
 918
 919 out:
 920         return found;
 921 }
 922
 923 static u64 prio_low = ~0ULL/2;
 924 static u64 prio_high = ~0ULL/2 - 1;
 925
 926 /* Add rule to given filterlist if not a duplicate. */
 927 static inline int audit_add_rule(struct audit_entry *entry)
 928 {
 929         struct audit_entry *e;
 930         struct audit_watch *watch = entry->rule.watch;
 931         struct audit_tree *tree = entry->rule.tree;
 932         struct list_head *list;
 933         int err;
 934 #ifdef CONFIG_AUDITSYSCALL
 935         int dont_count = 0;
 936
 937         /* If either of these, don't count towards total */
 938         if (entry->rule.listnr == AUDIT_FILTER_USER ||
 939                 entry->rule.listnr == AUDIT_FILTER_TYPE)
 940                 dont_count = 1;
 941 #endif
 942
 943         mutex_lock(&audit_filter_mutex);
 944         e = audit_find_rule(entry, &list);
 945         if (e) {
 946                 mutex_unlock(&audit_filter_mutex);
 947                 err = -EEXIST;
 948                 /* normally audit_add_tree_rule() will free it on failure */
 949                 if (tree)
 950                         audit_put_tree(tree);
 951                 goto error;
 952         }
 953
 954         if (watch) {
 955                 /* audit_filter_mutex is dropped and re-taken during this call */
 956                 err = audit_add_watch(&entry->rule, &list);
 957                 if (err) {
 958                         mutex_unlock(&audit_filter_mutex);
 959                         goto error;
 960                 }
 961         }
 962         if (tree) {
 963                 err = audit_add_tree_rule(&entry->rule);
 964                 if (err) {
 965                         mutex_unlock(&audit_filter_mutex);
 966                         goto error;
 967                 }
 968         }
 969
 970         entry->rule.prio = ~0ULL;
 971         if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
 972                 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
 973                         entry->rule.prio = ++prio_high;
 974                 else
 975                         entry->rule.prio = --prio_low;
 976         }
 977
 978         if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
 979                 list_add(&entry->rule.list,
 980                          &audit_rules_list[entry->rule.listnr]);
 981                 list_add_rcu(&entry->list, list);
 982                 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
 983         } else {
 984                 list_add_tail(&entry->rule.list,
 985                               &audit_rules_list[entry->rule.listnr]);
 986                 list_add_tail_rcu(&entry->list, list);
 987         }
 988 #ifdef CONFIG_AUDITSYSCALL
 989         if (!dont_count)
 990                 audit_n_rules++;
 991
 992         if (!audit_match_signal(entry))
 993                 audit_signals++;
 994 #endif
 995         mutex_unlock(&audit_filter_mutex);
 996
 997         return 0;
 998
 999 error:
1000         if (watch)
1001                 audit_put_watch(watch); /* tmp watch, matches initial get */
1002         return err;
1003 }
1004
1005 /* Remove an existing rule from filterlist. */
1006 static inline int audit_del_rule(struct audit_entry *entry)
1007 {
1008         struct audit_entry  *e;
1009         struct audit_watch *watch = entry->rule.watch;
1010         struct audit_tree *tree = entry->rule.tree;
1011         struct list_head *list;
1012         int ret = 0;
1013 #ifdef CONFIG_AUDITSYSCALL
1014         int dont_count = 0;
1015
1016         /* If either of these, don't count towards total */
1017         if (entry->rule.listnr == AUDIT_FILTER_USER ||
1018                 entry->rule.listnr == AUDIT_FILTER_TYPE)
1019                 dont_count = 1;
1020 #endif
1021
1022         mutex_lock(&audit_filter_mutex);
1023         e = audit_find_rule(entry, &list);
1024         if (!e) {
1025                 mutex_unlock(&audit_filter_mutex);
1026                 ret = -ENOENT;
1027                 goto out;
1028         }
1029
1030         if (e->rule.watch)
1031                 audit_remove_watch_rule(&e->rule);
1032
1033         if (e->rule.tree)
1034                 audit_remove_tree_rule(&e->rule);
1035
1036         list_del_rcu(&e->list);
1037         list_del(&e->rule.list);
1038         call_rcu(&e->rcu, audit_free_rule_rcu);
1039
1040 #ifdef CONFIG_AUDITSYSCALL
1041         if (!dont_count)
1042                 audit_n_rules--;
1043
1044         if (!audit_match_signal(entry))
1045                 audit_signals--;
1046 #endif
1047         mutex_unlock(&audit_filter_mutex);
1048
1049 out:
1050         if (watch)
1051                 audit_put_watch(watch); /* match initial get */
1052         if (tree)
1053                 audit_put_tree(tree);   /* that's the temporary one */
1054
1055         return ret;
1056 }
1057
1058 /* List rules using struct audit_rule.  Exists for backward
1059  * compatibility with userspace. */
1060 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1061 {
1062         struct sk_buff *skb;
1063         struct audit_krule *r;
1064         int i;
1065
1066         /* This is a blocking read, so use audit_filter_mutex instead of rcu
1067          * iterator to sync with list writers. */
1068         for (i=0; i<AUDIT_NR_FILTERS; i++) {
1069                 list_for_each_entry(r, &audit_rules_list[i], list) {
1070                         struct audit_rule *rule;
1071
1072                         rule = audit_krule_to_rule(r);
1073                         if (unlikely(!rule))
1074                                 break;
1075                         skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1076                                          rule, sizeof(*rule));
1077                         if (skb)
1078                                 skb_queue_tail(q, skb);
1079                         kfree(rule);
1080                 }
1081         }
1082         skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1083         if (skb)
1084                 skb_queue_tail(q, skb);
1085 }
1086
1087 /* List rules using struct audit_rule_data. */
1088 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1089 {
1090         struct sk_buff *skb;
1091         struct audit_krule *r;
1092         int i;
1093
1094         /* This is a blocking read, so use audit_filter_mutex instead of rcu
1095          * iterator to sync with list writers. */
1096         for (i=0; i<AUDIT_NR_FILTERS; i++) {
1097                 list_for_each_entry(r, &audit_rules_list[i], list) {
1098                         struct audit_rule_data *data;
1099
1100                         data = audit_krule_to_data(r);
1101                         if (unlikely(!data))
1102                                 break;
1103                         skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1104                                          data, sizeof(*data) + data->buflen);
1105                         if (skb)
1106                                 skb_queue_tail(q, skb);
1107                         kfree(data);
1108                 }
1109         }
1110         skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1111         if (skb)
1112                 skb_queue_tail(q, skb);
1113 }
1114
1115 /* Log rule additions and removals */
1116 static void audit_log_rule_change(kuid_t loginuid, u32 sessionid, u32 sid,
1117                                   char *action, struct audit_krule *rule,
1118                                   int res)
1119 {
1120         struct audit_buffer *ab;
1121
1122         if (!audit_enabled)
1123                 return;
1124
1125         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1126         if (!ab)
1127                 return;
1128         audit_log_format(ab, "auid=%u ses=%u",
1129                          from_kuid(&init_user_ns, loginuid), sessionid);
1130         if (sid) {
1131                 char *ctx = NULL;
1132                 u32 len;
1133                 if (security_secid_to_secctx(sid, &ctx, &len))
1134                         audit_log_format(ab, " ssid=%u", sid);
1135                 else {
1136                         audit_log_format(ab, " subj=%s", ctx);
1137                         security_release_secctx(ctx, len);
1138                 }
1139         }
1140         audit_log_format(ab, " op=");
1141         audit_log_string(ab, action);
1142         audit_log_key(ab, rule->filterkey);
1143         audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1144         audit_log_end(ab);
1145 }
1146
1147 /**
1148  * audit_receive_filter - apply all rules to the specified message type
1149  * @type: audit message type
1150  * @pid: target pid for netlink audit messages
1151  * @seq: netlink audit message sequence (serial) number
1152  * @data: payload data
1153  * @datasz: size of payload data
1154  * @loginuid: loginuid of sender
1155  * @sessionid: sessionid for netlink audit message
1156  * @sid: SE Linux Security ID of sender
1157  */
1158 int audit_receive_filter(int type, int pid, int seq, void *data,
1159                          size_t datasz, kuid_t loginuid, u32 sessionid, u32 sid)
1160 {
1161         struct task_struct *tsk;
1162         struct audit_netlink_list *dest;
1163         int err = 0;
1164         struct audit_entry *entry;
1165
1166         switch (type) {
1167         case AUDIT_LIST:
1168         case AUDIT_LIST_RULES:
1169                 /* We can't just spew out the rules here because we might fill
1170                  * the available socket buffer space and deadlock waiting for
1171                  * auditctl to read from it... which isn't ever going to
1172                  * happen if we're actually running in the context of auditctl
1173                  * trying to _send_ the stuff */
1174
1175                 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1176                 if (!dest)
1177                         return -ENOMEM;
1178                 dest->pid = pid;
1179                 skb_queue_head_init(&dest->q);
1180
1181                 mutex_lock(&audit_filter_mutex);
1182                 if (type == AUDIT_LIST)
1183                         audit_list(pid, seq, &dest->q);
1184                 else
1185                         audit_list_rules(pid, seq, &dest->q);
1186                 mutex_unlock(&audit_filter_mutex);
1187
1188                 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1189                 if (IS_ERR(tsk)) {
1190                         skb_queue_purge(&dest->q);
1191                         kfree(dest);
1192                         err = PTR_ERR(tsk);
1193                 }
1194                 break;
1195         case AUDIT_ADD:
1196         case AUDIT_ADD_RULE:
1197                 if (type == AUDIT_ADD)
1198                         entry = audit_rule_to_entry(data);
1199                 else
1200                         entry = audit_data_to_entry(data, datasz);
1201                 if (IS_ERR(entry))
1202                         return PTR_ERR(entry);
1203
1204                 err = audit_add_rule(entry);
1205                 audit_log_rule_change(loginuid, sessionid, sid, "add rule",
1206                                       &entry->rule, !err);
1207
1208                 if (err)
1209                         audit_free_rule(entry);
1210                 break;
1211         case AUDIT_DEL:
1212         case AUDIT_DEL_RULE:
1213                 if (type == AUDIT_DEL)
1214                         entry = audit_rule_to_entry(data);
1215                 else
1216                         entry = audit_data_to_entry(data, datasz);
1217                 if (IS_ERR(entry))
1218                         return PTR_ERR(entry);
1219
1220                 err = audit_del_rule(entry);
1221                 audit_log_rule_change(loginuid, sessionid, sid, "remove rule",
1222                                       &entry->rule, !err);
1223
1224                 audit_free_rule(entry);
1225                 break;
1226         default:
1227                 return -EINVAL;
1228         }
1229
1230         return err;
1231 }
1232
1233 int audit_comparator(u32 left, u32 op, u32 right)
1234 {
1235         switch (op) {
1236         case Audit_equal:
1237                 return (left == right);
1238         case Audit_not_equal:
1239                 return (left != right);
1240         case Audit_lt:
1241                 return (left < right);
1242         case Audit_le:
1243                 return (left <= right);
1244         case Audit_gt:
1245                 return (left > right);
1246         case Audit_ge:
1247                 return (left >= right);
1248         case Audit_bitmask:
1249                 return (left & right);
1250         case Audit_bittest:
1251                 return ((left & right) == right);
1252         default:
1253                 BUG();
1254                 return 0;
1255         }
1256 }
1257
1258 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1259 {
1260         switch (op) {
1261         case Audit_equal:
1262                 return uid_eq(left, right);
1263         case Audit_not_equal:
1264                 return !uid_eq(left, right);
1265         case Audit_lt:
1266                 return uid_lt(left, right);
1267         case Audit_le:
1268                 return uid_lte(left, right);
1269         case Audit_gt:
1270                 return uid_gt(left, right);
1271         case Audit_ge:
1272                 return uid_gte(left, right);
1273         case Audit_bitmask:
1274         case Audit_bittest:
1275         default:
1276                 BUG();
1277                 return 0;
1278         }
1279 }
1280
1281 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1282 {
1283         switch (op) {
1284         case Audit_equal:
1285                 return gid_eq(left, right);
1286         case Audit_not_equal:
1287                 return !gid_eq(left, right);
1288         case Audit_lt:
1289                 return gid_lt(left, right);
1290         case Audit_le:
1291                 return gid_lte(left, right);
1292         case Audit_gt:
1293                 return gid_gt(left, right);
1294         case Audit_ge:
1295                 return gid_gte(left, right);
1296         case Audit_bitmask:
1297         case Audit_bittest:
1298         default:
1299                 BUG();
1300                 return 0;
1301         }
1302 }
1303
1304 /**
1305  * parent_len - find the length of the parent portion of a pathname
1306  * @path: pathname of which to determine length
1307  */
1308 int parent_len(const char *path)
1309 {
1310         int plen;
1311         const char *p;
1312
1313         plen = strlen(path);
1314
1315         if (plen == 0)
1316                 return plen;
1317
1318         /* disregard trailing slashes */
1319         p = path + plen - 1;
1320         while ((*p == '/') && (p > path))
1321                 p--;
1322
1323         /* walk backward until we find the next slash or hit beginning */
1324         while ((*p != '/') && (p > path))
1325                 p--;
1326
1327         /* did we find a slash? Then increment to include it in path */
1328         if (*p == '/')
1329                 p++;
1330
1331         return p - path;
1332 }
1333
1334 /**
1335  * audit_compare_dname_path - compare given dentry name with last component in
1336  *                            given path. Return of 0 indicates a match.
1337  * @dname:      dentry name that we're comparing
1338  * @path:       full pathname that we're comparing
1339  * @parentlen:  length of the parent if known. Passing in AUDIT_NAME_FULL
1340  *              here indicates that we must compute this value.
1341  */
1342 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1343 {
1344         int dlen, pathlen;
1345         const char *p;
1346
1347         dlen = strlen(dname);
1348         pathlen = strlen(path);
1349         if (pathlen < dlen)
1350                 return 1;
1351
1352         parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1353         if (pathlen - parentlen != dlen)
1354                 return 1;
1355
1356         p = path + parentlen;
1357
1358         return strncmp(p, dname, dlen);
1359 }
1360
1361 static int audit_filter_user_rules(struct audit_krule *rule,
1362                                    enum audit_state *state)
1363 {
1364         int i;
1365
1366         for (i = 0; i < rule->field_count; i++) {
1367                 struct audit_field *f = &rule->fields[i];
1368                 int result = 0;
1369                 u32 sid;
1370
1371                 switch (f->type) {
1372                 case AUDIT_PID:
1373                         result = audit_comparator(task_pid_vnr(current), f->op, f->val);
1374                         break;
1375                 case AUDIT_UID:
1376                         result = audit_uid_comparator(current_uid(), f->op, f->uid);
1377                         break;
1378                 case AUDIT_GID:
1379                         result = audit_gid_comparator(current_gid(), f->op, f->gid);
1380                         break;
1381                 case AUDIT_LOGINUID:
1382                         result = audit_uid_comparator(audit_get_loginuid(current),
1383                                                   f->op, f->uid);
1384                         break;
1385                 case AUDIT_SUBJ_USER:
1386                 case AUDIT_SUBJ_ROLE:
1387                 case AUDIT_SUBJ_TYPE:
1388                 case AUDIT_SUBJ_SEN:
1389                 case AUDIT_SUBJ_CLR:
1390                         if (f->lsm_rule) {
1391                                 security_task_getsecid(current, &sid);
1392                                 result = security_audit_rule_match(sid,
1393                                                                    f->type,
1394                                                                    f->op,
1395                                                                    f->lsm_rule,
1396                                                                    NULL);
1397                         }
1398                         break;
1399                 }
1400
1401                 if (!result)
1402                         return 0;
1403         }
1404         switch (rule->action) {
1405         case AUDIT_NEVER:    *state = AUDIT_DISABLED;       break;
1406         case AUDIT_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
1407         }
1408         return 1;
1409 }
1410
1411 int audit_filter_user(void)
1412 {
1413         enum audit_state state = AUDIT_DISABLED;
1414         struct audit_entry *e;
1415         int ret = 1;
1416
1417         rcu_read_lock();
1418         list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1419                 if (audit_filter_user_rules(&e->rule, &state)) {
1420                         if (state == AUDIT_DISABLED)
1421                                 ret = 0;
1422                         break;
1423                 }
1424         }
1425         rcu_read_unlock();
1426
1427         return ret; /* Audit by default */
1428 }
1429
1430 int audit_filter_type(int type)
1431 {
1432         struct audit_entry *e;
1433         int result = 0;
1434
1435         rcu_read_lock();
1436         if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1437                 goto unlock_and_return;
1438
1439         list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1440                                 list) {
1441                 int i;
1442                 for (i = 0; i < e->rule.field_count; i++) {
1443                         struct audit_field *f = &e->rule.fields[i];
1444                         if (f->type == AUDIT_MSGTYPE) {
1445                                 result = audit_comparator(type, f->op, f->val);
1446                                 if (!result)
1447                                         break;
1448                         }
1449                 }
1450                 if (result)
1451                         goto unlock_and_return;
1452         }
1453 unlock_and_return:
1454         rcu_read_unlock();
1455         return result;
1456 }
1457
1458 static int update_lsm_rule(struct audit_krule *r)
1459 {
1460         struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1461         struct audit_entry *nentry;
1462         int err = 0;
1463
1464         if (!security_audit_rule_known(r))
1465                 return 0;
1466
1467         nentry = audit_dupe_rule(r);
1468         if (IS_ERR(nentry)) {
1469                 /* save the first error encountered for the
1470                  * return value */
1471                 err = PTR_ERR(nentry);
1472                 audit_panic("error updating LSM filters");
1473                 if (r->watch)
1474                         list_del(&r->rlist);
1475                 list_del_rcu(&entry->list);
1476                 list_del(&r->list);
1477         } else {
1478                 if (r->watch || r->tree)
1479                         list_replace_init(&r->rlist, &nentry->rule.rlist);
1480                 list_replace_rcu(&entry->list, &nentry->list);
1481                 list_replace(&r->list, &nentry->rule.list);
1482         }
1483         call_rcu(&entry->rcu, audit_free_rule_rcu);
1484
1485         return err;
1486 }
1487
1488 /* This function will re-initialize the lsm_rule field of all applicable rules.
1489  * It will traverse the filter lists serarching for rules that contain LSM
1490  * specific filter fields.  When such a rule is found, it is copied, the
1491  * LSM field is re-initialized, and the old rule is replaced with the
1492  * updated rule. */
1493 int audit_update_lsm_rules(void)
1494 {
1495         struct audit_krule *r, *n;
1496         int i, err = 0;
1497
1498         /* audit_filter_mutex synchronizes the writers */
1499         mutex_lock(&audit_filter_mutex);
1500
1501         for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1502                 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1503                         int res = update_lsm_rule(r);
1504                         if (!err)
1505                                 err = res;
1506                 }
1507         }
1508         mutex_unlock(&audit_filter_mutex);
1509
1510         return err;
1511 }