kernel/auditfilter.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
audit_free_lsm_field
audit_free_rule
audit_free_rule_rcu
audit_init_entry
audit_unpack_string
audit_to_inode
audit_register_class
audit_match_class
audit_match_class_bits
audit_match_signal
audit_to_entry_common
audit_to_op
audit_field_valid
audit_data_to_entry
audit_pack_string
audit_krule_to_data
audit_compare_rule
audit_dupe_lsm_field
audit_dupe_rule
audit_find_rule
audit_add_rule
audit_del_rule
audit_list_rules
audit_log_rule_change
audit_rule_change
audit_list_rules_send
audit_comparator
audit_uid_comparator
audit_gid_comparator
parent_len
audit_compare_dname_path
audit_filter
update_lsm_rule
audit_update_lsm_rules
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* auditfilter.c -- filtering of audit events
   3  *
   4  * Copyright 2003-2004 Red Hat, Inc.
   5  * Copyright 2005 Hewlett-Packard Development Company, L.P.
   6  * Copyright 2005 IBM Corporation
   7  */
   8 
   9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10 
  11 #include <linux/kernel.h>
  12 #include <linux/audit.h>
  13 #include <linux/kthread.h>
  14 #include <linux/mutex.h>
  15 #include <linux/fs.h>
  16 #include <linux/namei.h>
  17 #include <linux/netlink.h>
  18 #include <linux/sched.h>
  19 #include <linux/slab.h>
  20 #include <linux/security.h>
  21 #include <net/net_namespace.h>
  22 #include <net/sock.h>
  23 #include "audit.h"
  24 
  25 /*
  26  * Locking model:
  27  *
  28  * audit_filter_mutex:
  29  *              Synchronizes writes and blocking reads of audit's filterlist
  30  *              data.  Rcu is used to traverse the filterlist and access
  31  *              contents of structs audit_entry, audit_watch and opaque
  32  *              LSM rules during filtering.  If modified, these structures
  33  *              must be copied and replace their counterparts in the filterlist.
  34  *              An audit_parent struct is not accessed during filtering, so may
  35  *              be written directly provided audit_filter_mutex is held.
  36  */
  37 
  38 /* Audit filter lists, defined in <linux/audit.h> */
  39 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
  40         LIST_HEAD_INIT(audit_filter_list[0]),
  41         LIST_HEAD_INIT(audit_filter_list[1]),
  42         LIST_HEAD_INIT(audit_filter_list[2]),
  43         LIST_HEAD_INIT(audit_filter_list[3]),
  44         LIST_HEAD_INIT(audit_filter_list[4]),
  45         LIST_HEAD_INIT(audit_filter_list[5]),
  46         LIST_HEAD_INIT(audit_filter_list[6]),
  47 #if AUDIT_NR_FILTERS != 7
  48 #error Fix audit_filter_list initialiser
  49 #endif
  50 };
  51 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
  52         LIST_HEAD_INIT(audit_rules_list[0]),
  53         LIST_HEAD_INIT(audit_rules_list[1]),
  54         LIST_HEAD_INIT(audit_rules_list[2]),
  55         LIST_HEAD_INIT(audit_rules_list[3]),
  56         LIST_HEAD_INIT(audit_rules_list[4]),
  57         LIST_HEAD_INIT(audit_rules_list[5]),
  58         LIST_HEAD_INIT(audit_rules_list[6]),
  59 };
  60 
  61 DEFINE_MUTEX(audit_filter_mutex);
  62 
  63 static void audit_free_lsm_field(struct audit_field *f)
  64 {
  65         switch (f->type) {
  66         case AUDIT_SUBJ_USER:
  67         case AUDIT_SUBJ_ROLE:
  68         case AUDIT_SUBJ_TYPE:
  69         case AUDIT_SUBJ_SEN:
  70         case AUDIT_SUBJ_CLR:
  71         case AUDIT_OBJ_USER:
  72         case AUDIT_OBJ_ROLE:
  73         case AUDIT_OBJ_TYPE:
  74         case AUDIT_OBJ_LEV_LOW:
  75         case AUDIT_OBJ_LEV_HIGH:
  76                 kfree(f->lsm_str);
  77                 security_audit_rule_free(f->lsm_rule);
  78         }
  79 }
  80 
  81 static inline void audit_free_rule(struct audit_entry *e)
  82 {
  83         int i;
  84         struct audit_krule *erule = &e->rule;
  85 
  86         /* some rules don't have associated watches */
  87         if (erule->watch)
  88                 audit_put_watch(erule->watch);
  89         if (erule->fields)
  90                 for (i = 0; i < erule->field_count; i++)
  91                         audit_free_lsm_field(&erule->fields[i]);
  92         kfree(erule->fields);
  93         kfree(erule->filterkey);
  94         kfree(e);
  95 }
  96 
  97 void audit_free_rule_rcu(struct rcu_head *head)
  98 {
  99         struct audit_entry *e = container_of(head, struct audit_entry, rcu);
 100         audit_free_rule(e);
 101 }
 102 
 103 /* Initialize an audit filterlist entry. */
 104 static inline struct audit_entry *audit_init_entry(u32 field_count)
 105 {
 106         struct audit_entry *entry;
 107         struct audit_field *fields;
 108 
 109         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 110         if (unlikely(!entry))
 111                 return NULL;
 112 
 113         fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL);
 114         if (unlikely(!fields)) {
 115                 kfree(entry);
 116                 return NULL;
 117         }
 118         entry->rule.fields = fields;
 119 
 120         return entry;
 121 }
 122 
 123 /* Unpack a filter field's string representation from user-space
 124  * buffer. */
 125 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
 126 {
 127         char *str;
 128 
 129         if (!*bufp || (len == 0) || (len > *remain))
 130                 return ERR_PTR(-EINVAL);
 131 
 132         /* Of the currently implemented string fields, PATH_MAX
 133          * defines the longest valid length.
 134          */
 135         if (len > PATH_MAX)
 136                 return ERR_PTR(-ENAMETOOLONG);
 137 
 138         str = kmalloc(len + 1, GFP_KERNEL);
 139         if (unlikely(!str))
 140                 return ERR_PTR(-ENOMEM);
 141 
 142         memcpy(str, *bufp, len);
 143         str[len] = 0;
 144         *bufp += len;
 145         *remain -= len;
 146 
 147         return str;
 148 }
 149 
 150 /* Translate an inode field to kernel representation. */
 151 static inline int audit_to_inode(struct audit_krule *krule,
 152                                  struct audit_field *f)
 153 {
 154         if (krule->listnr != AUDIT_FILTER_EXIT ||
 155             krule->inode_f || krule->watch || krule->tree ||
 156             (f->op != Audit_equal && f->op != Audit_not_equal))
 157                 return -EINVAL;
 158 
 159         krule->inode_f = f;
 160         return 0;
 161 }
 162 
 163 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
 164 
 165 int __init audit_register_class(int class, unsigned *list)
 166 {
 167         __u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL);
 168         if (!p)
 169                 return -ENOMEM;
 170         while (*list != ~0U) {
 171                 unsigned n = *list++;
 172                 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
 173                         kfree(p);
 174                         return -EINVAL;
 175                 }
 176                 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
 177         }
 178         if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
 179                 kfree(p);
 180                 return -EINVAL;
 181         }
 182         classes[class] = p;
 183         return 0;
 184 }
 185 
 186 int audit_match_class(int class, unsigned syscall)
 187 {
 188         if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
 189                 return 0;
 190         if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
 191                 return 0;
 192         return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
 193 }
 194 
 195 #ifdef CONFIG_AUDITSYSCALL
 196 static inline int audit_match_class_bits(int class, u32 *mask)
 197 {
 198         int i;
 199 
 200         if (classes[class]) {
 201                 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 202                         if (mask[i] & classes[class][i])
 203                                 return 0;
 204         }
 205         return 1;
 206 }
 207 
 208 static int audit_match_signal(struct audit_entry *entry)
 209 {
 210         struct audit_field *arch = entry->rule.arch_f;
 211 
 212         if (!arch) {
 213                 /* When arch is unspecified, we must check both masks on biarch
 214                  * as syscall number alone is ambiguous. */
 215                 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
 216                                                entry->rule.mask) &&
 217                         audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
 218                                                entry->rule.mask));
 219         }
 220 
 221         switch(audit_classify_arch(arch->val)) {
 222         case 0: /* native */
 223                 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
 224                                                entry->rule.mask));
 225         case 1: /* 32bit on biarch */
 226                 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
 227                                                entry->rule.mask));
 228         default:
 229                 return 1;
 230         }
 231 }
 232 #endif
 233 
 234 /* Common user-space to kernel rule translation. */
 235 static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
 236 {
 237         unsigned listnr;
 238         struct audit_entry *entry;
 239         int i, err;
 240 
 241         err = -EINVAL;
 242         listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
 243         switch(listnr) {
 244         default:
 245                 goto exit_err;
 246 #ifdef CONFIG_AUDITSYSCALL
 247         case AUDIT_FILTER_ENTRY:
 248                 pr_err("AUDIT_FILTER_ENTRY is deprecated\n");
 249                 goto exit_err;
 250         case AUDIT_FILTER_EXIT:
 251         case AUDIT_FILTER_TASK:
 252 #endif
 253         case AUDIT_FILTER_USER:
 254         case AUDIT_FILTER_EXCLUDE:
 255         case AUDIT_FILTER_FS:
 256                 ;
 257         }
 258         if (unlikely(rule->action == AUDIT_POSSIBLE)) {
 259                 pr_err("AUDIT_POSSIBLE is deprecated\n");
 260                 goto exit_err;
 261         }
 262         if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
 263                 goto exit_err;
 264         if (rule->field_count > AUDIT_MAX_FIELDS)
 265                 goto exit_err;
 266 
 267         err = -ENOMEM;
 268         entry = audit_init_entry(rule->field_count);
 269         if (!entry)
 270                 goto exit_err;
 271 
 272         entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
 273         entry->rule.listnr = listnr;
 274         entry->rule.action = rule->action;
 275         entry->rule.field_count = rule->field_count;
 276 
 277         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 278                 entry->rule.mask[i] = rule->mask[i];
 279 
 280         for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
 281                 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
 282                 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
 283                 __u32 *class;
 284 
 285                 if (!(*p & AUDIT_BIT(bit)))
 286                         continue;
 287                 *p &= ~AUDIT_BIT(bit);
 288                 class = classes[i];
 289                 if (class) {
 290                         int j;
 291                         for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
 292                                 entry->rule.mask[j] |= class[j];
 293                 }
 294         }
 295 
 296         return entry;
 297 
 298 exit_err:
 299         return ERR_PTR(err);
 300 }
 301 
 302 static u32 audit_ops[] =
 303 {
 304         [Audit_equal] = AUDIT_EQUAL,
 305         [Audit_not_equal] = AUDIT_NOT_EQUAL,
 306         [Audit_bitmask] = AUDIT_BIT_MASK,
 307         [Audit_bittest] = AUDIT_BIT_TEST,
 308         [Audit_lt] = AUDIT_LESS_THAN,
 309         [Audit_gt] = AUDIT_GREATER_THAN,
 310         [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
 311         [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
 312 };
 313 
 314 static u32 audit_to_op(u32 op)
 315 {
 316         u32 n;
 317         for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
 318                 ;
 319         return n;
 320 }
 321 
 322 /* check if an audit field is valid */
 323 static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
 324 {
 325         switch (f->type) {
 326         case AUDIT_MSGTYPE:
 327                 if (entry->rule.listnr != AUDIT_FILTER_EXCLUDE &&
 328                     entry->rule.listnr != AUDIT_FILTER_USER)
 329                         return -EINVAL;
 330                 break;
 331         case AUDIT_FSTYPE:
 332                 if (entry->rule.listnr != AUDIT_FILTER_FS)
 333                         return -EINVAL;
 334                 break;
 335         }
 336 
 337         switch (entry->rule.listnr) {
 338         case AUDIT_FILTER_FS:
 339                 switch(f->type) {
 340                 case AUDIT_FSTYPE:
 341                 case AUDIT_FILTERKEY:
 342                         break;
 343                 default:
 344                         return -EINVAL;
 345                 }
 346         }
 347 
 348         /* Check for valid field type and op */
 349         switch (f->type) {
 350         case AUDIT_ARG0:
 351         case AUDIT_ARG1:
 352         case AUDIT_ARG2:
 353         case AUDIT_ARG3:
 354         case AUDIT_PERS: /* <uapi/linux/personality.h> */
 355         case AUDIT_DEVMINOR:
 356                 /* all ops are valid */
 357                 break;
 358         case AUDIT_UID:
 359         case AUDIT_EUID:
 360         case AUDIT_SUID:
 361         case AUDIT_FSUID:
 362         case AUDIT_LOGINUID:
 363         case AUDIT_OBJ_UID:
 364         case AUDIT_GID:
 365         case AUDIT_EGID:
 366         case AUDIT_SGID:
 367         case AUDIT_FSGID:
 368         case AUDIT_OBJ_GID:
 369         case AUDIT_PID:
 370         case AUDIT_MSGTYPE:
 371         case AUDIT_PPID:
 372         case AUDIT_DEVMAJOR:
 373         case AUDIT_EXIT:
 374         case AUDIT_SUCCESS:
 375         case AUDIT_INODE:
 376         case AUDIT_SESSIONID:
 377         case AUDIT_SUBJ_SEN:
 378         case AUDIT_SUBJ_CLR:
 379         case AUDIT_OBJ_LEV_LOW:
 380         case AUDIT_OBJ_LEV_HIGH:
 381         case AUDIT_SADDR_FAM:
 382                 /* bit ops are only useful on syscall args */
 383                 if (f->op == Audit_bitmask || f->op == Audit_bittest)
 384                         return -EINVAL;
 385                 break;
 386         case AUDIT_SUBJ_USER:
 387         case AUDIT_SUBJ_ROLE:
 388         case AUDIT_SUBJ_TYPE:
 389         case AUDIT_OBJ_USER:
 390         case AUDIT_OBJ_ROLE:
 391         case AUDIT_OBJ_TYPE:
 392         case AUDIT_WATCH:
 393         case AUDIT_DIR:
 394         case AUDIT_FILTERKEY:
 395         case AUDIT_LOGINUID_SET:
 396         case AUDIT_ARCH:
 397         case AUDIT_FSTYPE:
 398         case AUDIT_PERM:
 399         case AUDIT_FILETYPE:
 400         case AUDIT_FIELD_COMPARE:
 401         case AUDIT_EXE:
 402                 /* only equal and not equal valid ops */
 403                 if (f->op != Audit_not_equal && f->op != Audit_equal)
 404                         return -EINVAL;
 405                 break;
 406         default:
 407                 /* field not recognized */
 408                 return -EINVAL;
 409         }
 410 
 411         /* Check for select valid field values */
 412         switch (f->type) {
 413         case AUDIT_LOGINUID_SET:
 414                 if ((f->val != 0) && (f->val != 1))
 415                         return -EINVAL;
 416                 break;
 417         case AUDIT_PERM:
 418                 if (f->val & ~15)
 419                         return -EINVAL;
 420                 break;
 421         case AUDIT_FILETYPE:
 422                 if (f->val & ~S_IFMT)
 423                         return -EINVAL;
 424                 break;
 425         case AUDIT_FIELD_COMPARE:
 426                 if (f->val > AUDIT_MAX_FIELD_COMPARE)
 427                         return -EINVAL;
 428                 break;
 429         case AUDIT_SADDR_FAM:
 430                 if (f->val >= AF_MAX)
 431                         return -EINVAL;
 432                 break;
 433         default:
 434                 break;
 435         }
 436 
 437         return 0;
 438 }
 439 
 440 /* Translate struct audit_rule_data to kernel's rule representation. */
 441 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
 442                                                size_t datasz)
 443 {
 444         int err = 0;
 445         struct audit_entry *entry;
 446         void *bufp;
 447         size_t remain = datasz - sizeof(struct audit_rule_data);
 448         int i;
 449         char *str;
 450         struct audit_fsnotify_mark *audit_mark;
 451 
 452         entry = audit_to_entry_common(data);
 453         if (IS_ERR(entry))
 454                 goto exit_nofree;
 455 
 456         bufp = data->buf;
 457         for (i = 0; i < data->field_count; i++) {
 458                 struct audit_field *f = &entry->rule.fields[i];
 459                 u32 f_val;
 460 
 461                 err = -EINVAL;
 462 
 463                 f->op = audit_to_op(data->fieldflags[i]);
 464                 if (f->op == Audit_bad)
 465                         goto exit_free;
 466 
 467                 f->type = data->fields[i];
 468                 f_val = data->values[i];
 469 
 470                 /* Support legacy tests for a valid loginuid */
 471                 if ((f->type == AUDIT_LOGINUID) && (f_val == AUDIT_UID_UNSET)) {
 472                         f->type = AUDIT_LOGINUID_SET;
 473                         f_val = 0;
 474                         entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
 475                 }
 476 
 477                 err = audit_field_valid(entry, f);
 478                 if (err)
 479                         goto exit_free;
 480 
 481                 err = -EINVAL;
 482                 switch (f->type) {
 483                 case AUDIT_LOGINUID:
 484                 case AUDIT_UID:
 485                 case AUDIT_EUID:
 486                 case AUDIT_SUID:
 487                 case AUDIT_FSUID:
 488                 case AUDIT_OBJ_UID:
 489                         f->uid = make_kuid(current_user_ns(), f_val);
 490                         if (!uid_valid(f->uid))
 491                                 goto exit_free;
 492                         break;
 493                 case AUDIT_GID:
 494                 case AUDIT_EGID:
 495                 case AUDIT_SGID:
 496                 case AUDIT_FSGID:
 497                 case AUDIT_OBJ_GID:
 498                         f->gid = make_kgid(current_user_ns(), f_val);
 499                         if (!gid_valid(f->gid))
 500                                 goto exit_free;
 501                         break;
 502                 case AUDIT_ARCH:
 503                         f->val = f_val;
 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                                 err = PTR_ERR(str);
 519                                 goto exit_free;
 520                         }
 521                         entry->rule.buflen += f_val;
 522                         f->lsm_str = str;
 523                         err = security_audit_rule_init(f->type, f->op, str,
 524                                                        (void **)&f->lsm_rule);
 525                         /* Keep currently invalid fields around in case they
 526                          * become valid after a policy reload. */
 527                         if (err == -EINVAL) {
 528                                 pr_warn("audit rule for LSM \'%s\' is invalid\n",
 529                                         str);
 530                                 err = 0;
 531                         } else if (err)
 532                                 goto exit_free;
 533                         break;
 534                 case AUDIT_WATCH:
 535                         str = audit_unpack_string(&bufp, &remain, f_val);
 536                         if (IS_ERR(str)) {
 537                                 err = PTR_ERR(str);
 538                                 goto exit_free;
 539                         }
 540                         err = audit_to_watch(&entry->rule, str, f_val, f->op);
 541                         if (err) {
 542                                 kfree(str);
 543                                 goto exit_free;
 544                         }
 545                         entry->rule.buflen += f_val;
 546                         break;
 547                 case AUDIT_DIR:
 548                         str = audit_unpack_string(&bufp, &remain, f_val);
 549                         if (IS_ERR(str)) {
 550                                 err = PTR_ERR(str);
 551                                 goto exit_free;
 552                         }
 553                         err = audit_make_tree(&entry->rule, str, f->op);
 554                         kfree(str);
 555                         if (err)
 556                                 goto exit_free;
 557                         entry->rule.buflen += f_val;
 558                         break;
 559                 case AUDIT_INODE:
 560                         f->val = f_val;
 561                         err = audit_to_inode(&entry->rule, f);
 562                         if (err)
 563                                 goto exit_free;
 564                         break;
 565                 case AUDIT_FILTERKEY:
 566                         if (entry->rule.filterkey || f_val > AUDIT_MAX_KEY_LEN)
 567                                 goto exit_free;
 568                         str = audit_unpack_string(&bufp, &remain, f_val);
 569                         if (IS_ERR(str)) {
 570                                 err = PTR_ERR(str);
 571                                 goto exit_free;
 572                         }
 573                         entry->rule.buflen += f_val;
 574                         entry->rule.filterkey = str;
 575                         break;
 576                 case AUDIT_EXE:
 577                         if (entry->rule.exe || f_val > PATH_MAX)
 578                                 goto exit_free;
 579                         str = audit_unpack_string(&bufp, &remain, f_val);
 580                         if (IS_ERR(str)) {
 581                                 err = PTR_ERR(str);
 582                                 goto exit_free;
 583                         }
 584                         audit_mark = audit_alloc_mark(&entry->rule, str, f_val);
 585                         if (IS_ERR(audit_mark)) {
 586                                 kfree(str);
 587                                 err = PTR_ERR(audit_mark);
 588                                 goto exit_free;
 589                         }
 590                         entry->rule.buflen += f_val;
 591                         entry->rule.exe = audit_mark;
 592                         break;
 593                 default:
 594                         f->val = f_val;
 595                         break;
 596                 }
 597         }
 598 
 599         if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
 600                 entry->rule.inode_f = NULL;
 601 
 602 exit_nofree:
 603         return entry;
 604 
 605 exit_free:
 606         if (entry->rule.tree)
 607                 audit_put_tree(entry->rule.tree); /* that's the temporary one */
 608         if (entry->rule.exe)
 609                 audit_remove_mark(entry->rule.exe); /* that's the template one */
 610         audit_free_rule(entry);
 611         return ERR_PTR(err);
 612 }
 613 
 614 /* Pack a filter field's string representation into data block. */
 615 static inline size_t audit_pack_string(void **bufp, const char *str)
 616 {
 617         size_t len = strlen(str);
 618 
 619         memcpy(*bufp, str, len);
 620         *bufp += len;
 621 
 622         return len;
 623 }
 624 
 625 /* Translate kernel rule representation to struct audit_rule_data. */
 626 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
 627 {
 628         struct audit_rule_data *data;
 629         void *bufp;
 630         int i;
 631 
 632         data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
 633         if (unlikely(!data))
 634                 return NULL;
 635         memset(data, 0, sizeof(*data));
 636 
 637         data->flags = krule->flags | krule->listnr;
 638         data->action = krule->action;
 639         data->field_count = krule->field_count;
 640         bufp = data->buf;
 641         for (i = 0; i < data->field_count; i++) {
 642                 struct audit_field *f = &krule->fields[i];
 643 
 644                 data->fields[i] = f->type;
 645                 data->fieldflags[i] = audit_ops[f->op];
 646                 switch(f->type) {
 647                 case AUDIT_SUBJ_USER:
 648                 case AUDIT_SUBJ_ROLE:
 649                 case AUDIT_SUBJ_TYPE:
 650                 case AUDIT_SUBJ_SEN:
 651                 case AUDIT_SUBJ_CLR:
 652                 case AUDIT_OBJ_USER:
 653                 case AUDIT_OBJ_ROLE:
 654                 case AUDIT_OBJ_TYPE:
 655                 case AUDIT_OBJ_LEV_LOW:
 656                 case AUDIT_OBJ_LEV_HIGH:
 657                         data->buflen += data->values[i] =
 658                                 audit_pack_string(&bufp, f->lsm_str);
 659                         break;
 660                 case AUDIT_WATCH:
 661                         data->buflen += data->values[i] =
 662                                 audit_pack_string(&bufp,
 663                                                   audit_watch_path(krule->watch));
 664                         break;
 665                 case AUDIT_DIR:
 666                         data->buflen += data->values[i] =
 667                                 audit_pack_string(&bufp,
 668                                                   audit_tree_path(krule->tree));
 669                         break;
 670                 case AUDIT_FILTERKEY:
 671                         data->buflen += data->values[i] =
 672                                 audit_pack_string(&bufp, krule->filterkey);
 673                         break;
 674                 case AUDIT_EXE:
 675                         data->buflen += data->values[i] =
 676                                 audit_pack_string(&bufp, audit_mark_path(krule->exe));
 677                         break;
 678                 case AUDIT_LOGINUID_SET:
 679                         if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
 680                                 data->fields[i] = AUDIT_LOGINUID;
 681                                 data->values[i] = AUDIT_UID_UNSET;
 682                                 break;
 683                         }
 684                         /* fall through - if set */
 685                 default:
 686                         data->values[i] = f->val;
 687                 }
 688         }
 689         for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
 690 
 691         return data;
 692 }
 693 
 694 /* Compare two rules in kernel format.  Considered success if rules
 695  * don't match. */
 696 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
 697 {
 698         int i;
 699 
 700         if (a->flags != b->flags ||
 701             a->pflags != b->pflags ||
 702             a->listnr != b->listnr ||
 703             a->action != b->action ||
 704             a->field_count != b->field_count)
 705                 return 1;
 706 
 707         for (i = 0; i < a->field_count; i++) {
 708                 if (a->fields[i].type != b->fields[i].type ||
 709                     a->fields[i].op != b->fields[i].op)
 710                         return 1;
 711 
 712                 switch(a->fields[i].type) {
 713                 case AUDIT_SUBJ_USER:
 714                 case AUDIT_SUBJ_ROLE:
 715                 case AUDIT_SUBJ_TYPE:
 716                 case AUDIT_SUBJ_SEN:
 717                 case AUDIT_SUBJ_CLR:
 718                 case AUDIT_OBJ_USER:
 719                 case AUDIT_OBJ_ROLE:
 720                 case AUDIT_OBJ_TYPE:
 721                 case AUDIT_OBJ_LEV_LOW:
 722                 case AUDIT_OBJ_LEV_HIGH:
 723                         if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
 724                                 return 1;
 725                         break;
 726                 case AUDIT_WATCH:
 727                         if (strcmp(audit_watch_path(a->watch),
 728                                    audit_watch_path(b->watch)))
 729                                 return 1;
 730                         break;
 731                 case AUDIT_DIR:
 732                         if (strcmp(audit_tree_path(a->tree),
 733                                    audit_tree_path(b->tree)))
 734                                 return 1;
 735                         break;
 736                 case AUDIT_FILTERKEY:
 737                         /* both filterkeys exist based on above type compare */
 738                         if (strcmp(a->filterkey, b->filterkey))
 739                                 return 1;
 740                         break;
 741                 case AUDIT_EXE:
 742                         /* both paths exist based on above type compare */
 743                         if (strcmp(audit_mark_path(a->exe),
 744                                    audit_mark_path(b->exe)))
 745                                 return 1;
 746                         break;
 747                 case AUDIT_UID:
 748                 case AUDIT_EUID:
 749                 case AUDIT_SUID:
 750                 case AUDIT_FSUID:
 751                 case AUDIT_LOGINUID:
 752                 case AUDIT_OBJ_UID:
 753                         if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
 754                                 return 1;
 755                         break;
 756                 case AUDIT_GID:
 757                 case AUDIT_EGID:
 758                 case AUDIT_SGID:
 759                 case AUDIT_FSGID:
 760                 case AUDIT_OBJ_GID:
 761                         if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
 762                                 return 1;
 763                         break;
 764                 default:
 765                         if (a->fields[i].val != b->fields[i].val)
 766                                 return 1;
 767                 }
 768         }
 769 
 770         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 771                 if (a->mask[i] != b->mask[i])
 772                         return 1;
 773 
 774         return 0;
 775 }
 776 
 777 /* Duplicate LSM field information.  The lsm_rule is opaque, so must be
 778  * re-initialized. */
 779 static inline int audit_dupe_lsm_field(struct audit_field *df,
 780                                            struct audit_field *sf)
 781 {
 782         int ret = 0;
 783         char *lsm_str;
 784 
 785         /* our own copy of lsm_str */
 786         lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
 787         if (unlikely(!lsm_str))
 788                 return -ENOMEM;
 789         df->lsm_str = lsm_str;
 790 
 791         /* our own (refreshed) copy of lsm_rule */
 792         ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
 793                                        (void **)&df->lsm_rule);
 794         /* Keep currently invalid fields around in case they
 795          * become valid after a policy reload. */
 796         if (ret == -EINVAL) {
 797                 pr_warn("audit rule for LSM \'%s\' is invalid\n",
 798                         df->lsm_str);
 799                 ret = 0;
 800         }
 801 
 802         return ret;
 803 }
 804 
 805 /* Duplicate an audit rule.  This will be a deep copy with the exception
 806  * of the watch - that pointer is carried over.  The LSM specific fields
 807  * will be updated in the copy.  The point is to be able to replace the old
 808  * rule with the new rule in the filterlist, then free the old rule.
 809  * The rlist element is undefined; list manipulations are handled apart from
 810  * the initial copy. */
 811 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
 812 {
 813         u32 fcount = old->field_count;
 814         struct audit_entry *entry;
 815         struct audit_krule *new;
 816         char *fk;
 817         int i, err = 0;
 818 
 819         entry = audit_init_entry(fcount);
 820         if (unlikely(!entry))
 821                 return ERR_PTR(-ENOMEM);
 822 
 823         new = &entry->rule;
 824         new->flags = old->flags;
 825         new->pflags = old->pflags;
 826         new->listnr = old->listnr;
 827         new->action = old->action;
 828         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 829                 new->mask[i] = old->mask[i];
 830         new->prio = old->prio;
 831         new->buflen = old->buflen;
 832         new->inode_f = old->inode_f;
 833         new->field_count = old->field_count;
 834 
 835         /*
 836          * note that we are OK with not refcounting here; audit_match_tree()
 837          * never dereferences tree and we can't get false positives there
 838          * since we'd have to have rule gone from the list *and* removed
 839          * before the chunks found by lookup had been allocated, i.e. before
 840          * the beginning of list scan.
 841          */
 842         new->tree = old->tree;
 843         memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
 844 
 845         /* deep copy this information, updating the lsm_rule fields, because
 846          * the originals will all be freed when the old rule is freed. */
 847         for (i = 0; i < fcount; i++) {
 848                 switch (new->fields[i].type) {
 849                 case AUDIT_SUBJ_USER:
 850                 case AUDIT_SUBJ_ROLE:
 851                 case AUDIT_SUBJ_TYPE:
 852                 case AUDIT_SUBJ_SEN:
 853                 case AUDIT_SUBJ_CLR:
 854                 case AUDIT_OBJ_USER:
 855                 case AUDIT_OBJ_ROLE:
 856                 case AUDIT_OBJ_TYPE:
 857                 case AUDIT_OBJ_LEV_LOW:
 858                 case AUDIT_OBJ_LEV_HIGH:
 859                         err = audit_dupe_lsm_field(&new->fields[i],
 860                                                        &old->fields[i]);
 861                         break;
 862                 case AUDIT_FILTERKEY:
 863                         fk = kstrdup(old->filterkey, GFP_KERNEL);
 864                         if (unlikely(!fk))
 865                                 err = -ENOMEM;
 866                         else
 867                                 new->filterkey = fk;
 868                         break;
 869                 case AUDIT_EXE:
 870                         err = audit_dupe_exe(new, old);
 871                         break;
 872                 }
 873                 if (err) {
 874                         if (new->exe)
 875                                 audit_remove_mark(new->exe);
 876                         audit_free_rule(entry);
 877                         return ERR_PTR(err);
 878                 }
 879         }
 880 
 881         if (old->watch) {
 882                 audit_get_watch(old->watch);
 883                 new->watch = old->watch;
 884         }
 885 
 886         return entry;
 887 }
 888 
 889 /* Find an existing audit rule.
 890  * Caller must hold audit_filter_mutex to prevent stale rule data. */
 891 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
 892                                            struct list_head **p)
 893 {
 894         struct audit_entry *e, *found = NULL;
 895         struct list_head *list;
 896         int h;
 897 
 898         if (entry->rule.inode_f) {
 899                 h = audit_hash_ino(entry->rule.inode_f->val);
 900                 *p = list = &audit_inode_hash[h];
 901         } else if (entry->rule.watch) {
 902                 /* we don't know the inode number, so must walk entire hash */
 903                 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
 904                         list = &audit_inode_hash[h];
 905                         list_for_each_entry(e, list, list)
 906                                 if (!audit_compare_rule(&entry->rule, &e->rule)) {
 907                                         found = e;
 908                                         goto out;
 909                                 }
 910                 }
 911                 goto out;
 912         } else {
 913                 *p = list = &audit_filter_list[entry->rule.listnr];
 914         }
 915 
 916         list_for_each_entry(e, list, list)
 917                 if (!audit_compare_rule(&entry->rule, &e->rule)) {
 918                         found = e;
 919                         goto out;
 920                 }
 921 
 922 out:
 923         return found;
 924 }
 925 
 926 static u64 prio_low = ~0ULL/2;
 927 static u64 prio_high = ~0ULL/2 - 1;
 928 
 929 /* Add rule to given filterlist if not a duplicate. */
 930 static inline int audit_add_rule(struct audit_entry *entry)
 931 {
 932         struct audit_entry *e;
 933         struct audit_watch *watch = entry->rule.watch;
 934         struct audit_tree *tree = entry->rule.tree;
 935         struct list_head *list;
 936         int err = 0;
 937 #ifdef CONFIG_AUDITSYSCALL
 938         int dont_count = 0;
 939 
 940         /* If any of these, don't count towards total */
 941         switch(entry->rule.listnr) {
 942         case AUDIT_FILTER_USER:
 943         case AUDIT_FILTER_EXCLUDE:
 944         case AUDIT_FILTER_FS:
 945                 dont_count = 1;
 946         }
 947 #endif
 948 
 949         mutex_lock(&audit_filter_mutex);
 950         e = audit_find_rule(entry, &list);
 951         if (e) {
 952                 mutex_unlock(&audit_filter_mutex);
 953                 err = -EEXIST;
 954                 /* normally audit_add_tree_rule() will free it on failure */
 955                 if (tree)
 956                         audit_put_tree(tree);
 957                 return err;
 958         }
 959 
 960         if (watch) {
 961                 /* audit_filter_mutex is dropped and re-taken during this call */
 962                 err = audit_add_watch(&entry->rule, &list);
 963                 if (err) {
 964                         mutex_unlock(&audit_filter_mutex);
 965                         /*
 966                          * normally audit_add_tree_rule() will free it
 967                          * on failure
 968                          */
 969                         if (tree)
 970                                 audit_put_tree(tree);
 971                         return err;
 972                 }
 973         }
 974         if (tree) {
 975                 err = audit_add_tree_rule(&entry->rule);
 976                 if (err) {
 977                         mutex_unlock(&audit_filter_mutex);
 978                         return err;
 979                 }
 980         }
 981 
 982         entry->rule.prio = ~0ULL;
 983         if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
 984                 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
 985                         entry->rule.prio = ++prio_high;
 986                 else
 987                         entry->rule.prio = --prio_low;
 988         }
 989 
 990         if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
 991                 list_add(&entry->rule.list,
 992                          &audit_rules_list[entry->rule.listnr]);
 993                 list_add_rcu(&entry->list, list);
 994                 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
 995         } else {
 996                 list_add_tail(&entry->rule.list,
 997                               &audit_rules_list[entry->rule.listnr]);
 998                 list_add_tail_rcu(&entry->list, list);
 999         }
1000 #ifdef CONFIG_AUDITSYSCALL
1001         if (!dont_count)
1002                 audit_n_rules++;
1003 
1004         if (!audit_match_signal(entry))
1005                 audit_signals++;
1006 #endif
1007         mutex_unlock(&audit_filter_mutex);
1008 
1009         return err;
1010 }
1011 
1012 /* Remove an existing rule from filterlist. */
1013 int audit_del_rule(struct audit_entry *entry)
1014 {
1015         struct audit_entry  *e;
1016         struct audit_tree *tree = entry->rule.tree;
1017         struct list_head *list;
1018         int ret = 0;
1019 #ifdef CONFIG_AUDITSYSCALL
1020         int dont_count = 0;
1021 
1022         /* If any of these, don't count towards total */
1023         switch(entry->rule.listnr) {
1024         case AUDIT_FILTER_USER:
1025         case AUDIT_FILTER_EXCLUDE:
1026         case AUDIT_FILTER_FS:
1027                 dont_count = 1;
1028         }
1029 #endif
1030 
1031         mutex_lock(&audit_filter_mutex);
1032         e = audit_find_rule(entry, &list);
1033         if (!e) {
1034                 ret = -ENOENT;
1035                 goto out;
1036         }
1037 
1038         if (e->rule.watch)
1039                 audit_remove_watch_rule(&e->rule);
1040 
1041         if (e->rule.tree)
1042                 audit_remove_tree_rule(&e->rule);
1043 
1044         if (e->rule.exe)
1045                 audit_remove_mark_rule(&e->rule);
1046 
1047 #ifdef CONFIG_AUDITSYSCALL
1048         if (!dont_count)
1049                 audit_n_rules--;
1050 
1051         if (!audit_match_signal(entry))
1052                 audit_signals--;
1053 #endif
1054 
1055         list_del_rcu(&e->list);
1056         list_del(&e->rule.list);
1057         call_rcu(&e->rcu, audit_free_rule_rcu);
1058 
1059 out:
1060         mutex_unlock(&audit_filter_mutex);
1061 
1062         if (tree)
1063                 audit_put_tree(tree);   /* that's the temporary one */
1064 
1065         return ret;
1066 }
1067 
1068 /* List rules using struct audit_rule_data. */
1069 static void audit_list_rules(int seq, struct sk_buff_head *q)
1070 {
1071         struct sk_buff *skb;
1072         struct audit_krule *r;
1073         int i;
1074 
1075         /* This is a blocking read, so use audit_filter_mutex instead of rcu
1076          * iterator to sync with list writers. */
1077         for (i=0; i<AUDIT_NR_FILTERS; i++) {
1078                 list_for_each_entry(r, &audit_rules_list[i], list) {
1079                         struct audit_rule_data *data;
1080 
1081                         data = audit_krule_to_data(r);
1082                         if (unlikely(!data))
1083                                 break;
1084                         skb = audit_make_reply(seq, AUDIT_LIST_RULES, 0, 1,
1085                                                data,
1086                                                sizeof(*data) + data->buflen);
1087                         if (skb)
1088                                 skb_queue_tail(q, skb);
1089                         kfree(data);
1090                 }
1091         }
1092         skb = audit_make_reply(seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1093         if (skb)
1094                 skb_queue_tail(q, skb);
1095 }
1096 
1097 /* Log rule additions and removals */
1098 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1099 {
1100         struct audit_buffer *ab;
1101 
1102         if (!audit_enabled)
1103                 return;
1104 
1105         ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1106         if (!ab)
1107                 return;
1108         audit_log_session_info(ab);
1109         audit_log_task_context(ab);
1110         audit_log_format(ab, " op=%s", action);
1111         audit_log_key(ab, rule->filterkey);
1112         audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1113         audit_log_end(ab);
1114 }
1115 
1116 /**
1117  * audit_rule_change - apply all rules to the specified message type
1118  * @type: audit message type
1119  * @seq: netlink audit message sequence (serial) number
1120  * @data: payload data
1121  * @datasz: size of payload data
1122  */
1123 int audit_rule_change(int type, int seq, void *data, size_t datasz)
1124 {
1125         int err = 0;
1126         struct audit_entry *entry;
1127 
1128         switch (type) {
1129         case AUDIT_ADD_RULE:
1130                 entry = audit_data_to_entry(data, datasz);
1131                 if (IS_ERR(entry))
1132                         return PTR_ERR(entry);
1133                 err = audit_add_rule(entry);
1134                 audit_log_rule_change("add_rule", &entry->rule, !err);
1135                 break;
1136         case AUDIT_DEL_RULE:
1137                 entry = audit_data_to_entry(data, datasz);
1138                 if (IS_ERR(entry))
1139                         return PTR_ERR(entry);
1140                 err = audit_del_rule(entry);
1141                 audit_log_rule_change("remove_rule", &entry->rule, !err);
1142                 break;
1143         default:
1144                 WARN_ON(1);
1145                 return -EINVAL;
1146         }
1147 
1148         if (err || type == AUDIT_DEL_RULE) {
1149                 if (entry->rule.exe)
1150                         audit_remove_mark(entry->rule.exe);
1151                 audit_free_rule(entry);
1152         }
1153 
1154         return err;
1155 }
1156 
1157 /**
1158  * audit_list_rules_send - list the audit rules
1159  * @request_skb: skb of request we are replying to (used to target the reply)
1160  * @seq: netlink audit message sequence (serial) number
1161  */
1162 int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1163 {
1164         u32 portid = NETLINK_CB(request_skb).portid;
1165         struct net *net = sock_net(NETLINK_CB(request_skb).sk);
1166         struct task_struct *tsk;
1167         struct audit_netlink_list *dest;
1168         int err = 0;
1169 
1170         /* We can't just spew out the rules here because we might fill
1171          * the available socket buffer space and deadlock waiting for
1172          * auditctl to read from it... which isn't ever going to
1173          * happen if we're actually running in the context of auditctl
1174          * trying to _send_ the stuff */
1175 
1176         dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1177         if (!dest)
1178                 return -ENOMEM;
1179         dest->net = get_net(net);
1180         dest->portid = portid;
1181         skb_queue_head_init(&dest->q);
1182 
1183         mutex_lock(&audit_filter_mutex);
1184         audit_list_rules(seq, &dest->q);
1185         mutex_unlock(&audit_filter_mutex);
1186 
1187         tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1188         if (IS_ERR(tsk)) {
1189                 skb_queue_purge(&dest->q);
1190                 kfree(dest);
1191                 err = PTR_ERR(tsk);
1192         }
1193 
1194         return err;
1195 }
1196 
1197 int audit_comparator(u32 left, u32 op, u32 right)
1198 {
1199         switch (op) {
1200         case Audit_equal:
1201                 return (left == right);
1202         case Audit_not_equal:
1203                 return (left != right);
1204         case Audit_lt:
1205                 return (left < right);
1206         case Audit_le:
1207                 return (left <= right);
1208         case Audit_gt:
1209                 return (left > right);
1210         case Audit_ge:
1211                 return (left >= right);
1212         case Audit_bitmask:
1213                 return (left & right);
1214         case Audit_bittest:
1215                 return ((left & right) == right);
1216         default:
1217                 return 0;
1218         }
1219 }
1220 
1221 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1222 {
1223         switch (op) {
1224         case Audit_equal:
1225                 return uid_eq(left, right);
1226         case Audit_not_equal:
1227                 return !uid_eq(left, right);
1228         case Audit_lt:
1229                 return uid_lt(left, right);
1230         case Audit_le:
1231                 return uid_lte(left, right);
1232         case Audit_gt:
1233                 return uid_gt(left, right);
1234         case Audit_ge:
1235                 return uid_gte(left, right);
1236         case Audit_bitmask:
1237         case Audit_bittest:
1238         default:
1239                 return 0;
1240         }
1241 }
1242 
1243 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1244 {
1245         switch (op) {
1246         case Audit_equal:
1247                 return gid_eq(left, right);
1248         case Audit_not_equal:
1249                 return !gid_eq(left, right);
1250         case Audit_lt:
1251                 return gid_lt(left, right);
1252         case Audit_le:
1253                 return gid_lte(left, right);
1254         case Audit_gt:
1255                 return gid_gt(left, right);
1256         case Audit_ge:
1257                 return gid_gte(left, right);
1258         case Audit_bitmask:
1259         case Audit_bittest:
1260         default:
1261                 return 0;
1262         }
1263 }
1264 
1265 /**
1266  * parent_len - find the length of the parent portion of a pathname
1267  * @path: pathname of which to determine length
1268  */
1269 int parent_len(const char *path)
1270 {
1271         int plen;
1272         const char *p;
1273 
1274         plen = strlen(path);
1275 
1276         if (plen == 0)
1277                 return plen;
1278 
1279         /* disregard trailing slashes */
1280         p = path + plen - 1;
1281         while ((*p == '/') && (p > path))
1282                 p--;
1283 
1284         /* walk backward until we find the next slash or hit beginning */
1285         while ((*p != '/') && (p > path))
1286                 p--;
1287 
1288         /* did we find a slash? Then increment to include it in path */
1289         if (*p == '/')
1290                 p++;
1291 
1292         return p - path;
1293 }
1294 
1295 /**
1296  * audit_compare_dname_path - compare given dentry name with last component in
1297  *                            given path. Return of 0 indicates a match.
1298  * @dname:      dentry name that we're comparing
1299  * @path:       full pathname that we're comparing
1300  * @parentlen:  length of the parent if known. Passing in AUDIT_NAME_FULL
1301  *              here indicates that we must compute this value.
1302  */
1303 int audit_compare_dname_path(const struct qstr *dname, const char *path, int parentlen)
1304 {
1305         int dlen, pathlen;
1306         const char *p;
1307 
1308         dlen = dname->len;
1309         pathlen = strlen(path);
1310         if (pathlen < dlen)
1311                 return 1;
1312 
1313         parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1314         if (pathlen - parentlen != dlen)
1315                 return 1;
1316 
1317         p = path + parentlen;
1318 
1319         return strncmp(p, dname->name, dlen);
1320 }
1321 
1322 int audit_filter(int msgtype, unsigned int listtype)
1323 {
1324         struct audit_entry *e;
1325         int ret = 1; /* Audit by default */
1326 
1327         rcu_read_lock();
1328         list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) {
1329                 int i, result = 0;
1330 
1331                 for (i = 0; i < e->rule.field_count; i++) {
1332                         struct audit_field *f = &e->rule.fields[i];
1333                         pid_t pid;
1334                         u32 sid;
1335 
1336                         switch (f->type) {
1337                         case AUDIT_PID:
1338                                 pid = task_pid_nr(current);
1339                                 result = audit_comparator(pid, f->op, f->val);
1340                                 break;
1341                         case AUDIT_UID:
1342                                 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1343                                 break;
1344                         case AUDIT_GID:
1345                                 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1346                                 break;
1347                         case AUDIT_LOGINUID:
1348                                 result = audit_uid_comparator(audit_get_loginuid(current),
1349                                                               f->op, f->uid);
1350                                 break;
1351                         case AUDIT_LOGINUID_SET:
1352                                 result = audit_comparator(audit_loginuid_set(current),
1353                                                           f->op, f->val);
1354                                 break;
1355                         case AUDIT_MSGTYPE:
1356                                 result = audit_comparator(msgtype, f->op, f->val);
1357                                 break;
1358                         case AUDIT_SUBJ_USER:
1359                         case AUDIT_SUBJ_ROLE:
1360                         case AUDIT_SUBJ_TYPE:
1361                         case AUDIT_SUBJ_SEN:
1362                         case AUDIT_SUBJ_CLR:
1363                                 if (f->lsm_rule) {
1364                                         security_task_getsecid(current, &sid);
1365                                         result = security_audit_rule_match(sid,
1366                                                    f->type, f->op, f->lsm_rule);
1367                                 }
1368                                 break;
1369                         case AUDIT_EXE:
1370                                 result = audit_exe_compare(current, e->rule.exe);
1371                                 if (f->op == Audit_not_equal)
1372                                         result = !result;
1373                                 break;
1374                         default:
1375                                 goto unlock_and_return;
1376                         }
1377                         if (result < 0) /* error */
1378                                 goto unlock_and_return;
1379                         if (!result)
1380                                 break;
1381                 }
1382                 if (result > 0) {
1383                         if (e->rule.action == AUDIT_NEVER || listtype == AUDIT_FILTER_EXCLUDE)
1384                                 ret = 0;
1385                         break;
1386                 }
1387         }
1388 unlock_and_return:
1389         rcu_read_unlock();
1390         return ret;
1391 }
1392 
1393 static int update_lsm_rule(struct audit_krule *r)
1394 {
1395         struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1396         struct audit_entry *nentry;
1397         int err = 0;
1398 
1399         if (!security_audit_rule_known(r))
1400                 return 0;
1401 
1402         nentry = audit_dupe_rule(r);
1403         if (entry->rule.exe)
1404                 audit_remove_mark(entry->rule.exe);
1405         if (IS_ERR(nentry)) {
1406                 /* save the first error encountered for the
1407                  * return value */
1408                 err = PTR_ERR(nentry);
1409                 audit_panic("error updating LSM filters");
1410                 if (r->watch)
1411                         list_del(&r->rlist);
1412                 list_del_rcu(&entry->list);
1413                 list_del(&r->list);
1414         } else {
1415                 if (r->watch || r->tree)
1416                         list_replace_init(&r->rlist, &nentry->rule.rlist);
1417                 list_replace_rcu(&entry->list, &nentry->list);
1418                 list_replace(&r->list, &nentry->rule.list);
1419         }
1420         call_rcu(&entry->rcu, audit_free_rule_rcu);
1421 
1422         return err;
1423 }
1424 
1425 /* This function will re-initialize the lsm_rule field of all applicable rules.
1426  * It will traverse the filter lists serarching for rules that contain LSM
1427  * specific filter fields.  When such a rule is found, it is copied, the
1428  * LSM field is re-initialized, and the old rule is replaced with the
1429  * updated rule. */
1430 int audit_update_lsm_rules(void)
1431 {
1432         struct audit_krule *r, *n;
1433         int i, err = 0;
1434 
1435         /* audit_filter_mutex synchronizes the writers */
1436         mutex_lock(&audit_filter_mutex);
1437 
1438         for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1439                 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1440                         int res = update_lsm_rule(r);
1441                         if (!err)
1442                                 err = res;
1443                 }
1444         }
1445         mutex_unlock(&audit_filter_mutex);
1446 
1447         return err;
1448 }
/* [<][>][^][v][top][bottom][index][help] */
root/kernel/auditfilter.c

DEFINITIONS
