linux/kernel/auditfilter.c
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   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> */
  48struct 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};
  59static 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
  68DEFINE_MUTEX(audit_filter_mutex);
  69
  70static 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
  89void 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. */
  96static 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. */
 117char *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. */
 143static 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
 155static __u32 *classes[AUDIT_SYSCALL_CLASSES];
 156
 157int __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
 178int 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
 188static 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
 200static 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. */
 227static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
 228{
 229        unsigned listnr;
 230        struct audit_entry *entry;
 231        int i, err;
 232
 233        err = -EINVAL;
 234        listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
 235        switch(listnr) {
 236        default:
 237                goto exit_err;
 238        case AUDIT_FILTER_USER:
 239        case AUDIT_FILTER_TYPE:
 240#ifdef CONFIG_AUDITSYSCALL
 241        case AUDIT_FILTER_ENTRY:
 242        case AUDIT_FILTER_EXIT:
 243        case AUDIT_FILTER_TASK:
 244#endif
 245                ;
 246        }
 247        if (unlikely(rule->action == AUDIT_POSSIBLE)) {
 248                printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
 249                goto exit_err;
 250        }
 251        if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
 252                goto exit_err;
 253        if (rule->field_count > AUDIT_MAX_FIELDS)
 254                goto exit_err;
 255
 256        err = -ENOMEM;
 257        entry = audit_init_entry(rule->field_count);
 258        if (!entry)
 259                goto exit_err;
 260
 261        entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
 262        entry->rule.listnr = listnr;
 263        entry->rule.action = rule->action;
 264        entry->rule.field_count = rule->field_count;
 265
 266        for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 267                entry->rule.mask[i] = rule->mask[i];
 268
 269        for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
 270                int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
 271                __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
 272                __u32 *class;
 273
 274                if (!(*p & AUDIT_BIT(bit)))
 275                        continue;
 276                *p &= ~AUDIT_BIT(bit);
 277                class = classes[i];
 278                if (class) {
 279                        int j;
 280                        for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
 281                                entry->rule.mask[j] |= class[j];
 282                }
 283        }
 284
 285        return entry;
 286
 287exit_err:
 288        return ERR_PTR(err);
 289}
 290
 291static u32 audit_ops[] =
 292{
 293        [Audit_equal] = AUDIT_EQUAL,
 294        [Audit_not_equal] = AUDIT_NOT_EQUAL,
 295        [Audit_bitmask] = AUDIT_BIT_MASK,
 296        [Audit_bittest] = AUDIT_BIT_TEST,
 297        [Audit_lt] = AUDIT_LESS_THAN,
 298        [Audit_gt] = AUDIT_GREATER_THAN,
 299        [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
 300        [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
 301};
 302
 303static u32 audit_to_op(u32 op)
 304{
 305        u32 n;
 306        for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
 307                ;
 308        return n;
 309}
 310
 311
 312/* Translate struct audit_rule to kernel's rule respresentation.
 313 * Exists for backward compatibility with userspace. */
 314static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
 315{
 316        struct audit_entry *entry;
 317        int err = 0;
 318        int i;
 319
 320        entry = audit_to_entry_common(rule);
 321        if (IS_ERR(entry))
 322                goto exit_nofree;
 323
 324        for (i = 0; i < rule->field_count; i++) {
 325                struct audit_field *f = &entry->rule.fields[i];
 326                u32 n;
 327
 328                n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
 329
 330                /* Support for legacy operators where
 331                 * AUDIT_NEGATE bit signifies != and otherwise assumes == */
 332                if (n & AUDIT_NEGATE)
 333                        f->op = Audit_not_equal;
 334                else if (!n)
 335                        f->op = Audit_equal;
 336                else
 337                        f->op = audit_to_op(n);
 338
 339                entry->rule.vers_ops = (n & AUDIT_OPERATORS) ? 2 : 1;
 340
 341                f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
 342                f->val = rule->values[i];
 343
 344                err = -EINVAL;
 345                if (f->op == Audit_bad)
 346                        goto exit_free;
 347
 348                switch(f->type) {
 349                default:
 350                        goto exit_free;
 351                case AUDIT_PID:
 352                case AUDIT_UID:
 353                case AUDIT_EUID:
 354                case AUDIT_SUID:
 355                case AUDIT_FSUID:
 356                case AUDIT_GID:
 357                case AUDIT_EGID:
 358                case AUDIT_SGID:
 359                case AUDIT_FSGID:
 360                case AUDIT_LOGINUID:
 361                case AUDIT_PERS:
 362                case AUDIT_MSGTYPE:
 363                case AUDIT_PPID:
 364                case AUDIT_DEVMAJOR:
 365                case AUDIT_DEVMINOR:
 366                case AUDIT_EXIT:
 367                case AUDIT_SUCCESS:
 368                        /* bit ops are only useful on syscall args */
 369                        if (f->op == Audit_bitmask || f->op == Audit_bittest)
 370                                goto exit_free;
 371                        break;
 372                case AUDIT_ARG0:
 373                case AUDIT_ARG1:
 374                case AUDIT_ARG2:
 375                case AUDIT_ARG3:
 376                        break;
 377                /* arch is only allowed to be = or != */
 378                case AUDIT_ARCH:
 379                        if (f->op != Audit_not_equal && f->op != Audit_equal)
 380                                goto exit_free;
 381                        entry->rule.arch_f = f;
 382                        break;
 383                case AUDIT_PERM:
 384                        if (f->val & ~15)
 385                                goto exit_free;
 386                        break;
 387                case AUDIT_FILETYPE:
 388                        if ((f->val & ~S_IFMT) > S_IFMT)
 389                                goto exit_free;
 390                        break;
 391                case AUDIT_INODE:
 392                        err = audit_to_inode(&entry->rule, f);
 393                        if (err)
 394                                goto exit_free;
 395                        break;
 396                }
 397        }
 398
 399        if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
 400                entry->rule.inode_f = NULL;
 401
 402exit_nofree:
 403        return entry;
 404
 405exit_free:
 406        audit_free_rule(entry);
 407        return ERR_PTR(err);
 408}
 409
 410/* Translate struct audit_rule_data to kernel's rule respresentation. */
 411static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
 412                                               size_t datasz)
 413{
 414        int err = 0;
 415        struct audit_entry *entry;
 416        void *bufp;
 417        size_t remain = datasz - sizeof(struct audit_rule_data);
 418        int i;
 419        char *str;
 420
 421        entry = audit_to_entry_common((struct audit_rule *)data);
 422        if (IS_ERR(entry))
 423                goto exit_nofree;
 424
 425        bufp = data->buf;
 426        entry->rule.vers_ops = 2;
 427        for (i = 0; i < data->field_count; i++) {
 428                struct audit_field *f = &entry->rule.fields[i];
 429
 430                err = -EINVAL;
 431
 432                f->op = audit_to_op(data->fieldflags[i]);
 433                if (f->op == Audit_bad)
 434                        goto exit_free;
 435
 436                f->type = data->fields[i];
 437                f->val = data->values[i];
 438                f->lsm_str = NULL;
 439                f->lsm_rule = NULL;
 440                switch(f->type) {
 441                case AUDIT_PID:
 442                case AUDIT_UID:
 443                case AUDIT_EUID:
 444                case AUDIT_SUID:
 445                case AUDIT_FSUID:
 446                case AUDIT_GID:
 447                case AUDIT_EGID:
 448                case AUDIT_SGID:
 449                case AUDIT_FSGID:
 450                case AUDIT_LOGINUID:
 451                case AUDIT_PERS:
 452                case AUDIT_MSGTYPE:
 453                case AUDIT_PPID:
 454                case AUDIT_DEVMAJOR:
 455                case AUDIT_DEVMINOR:
 456                case AUDIT_EXIT:
 457                case AUDIT_SUCCESS:
 458                case AUDIT_ARG0:
 459                case AUDIT_ARG1:
 460                case AUDIT_ARG2:
 461                case AUDIT_ARG3:
 462                        break;
 463                case AUDIT_ARCH:
 464                        entry->rule.arch_f = f;
 465                        break;
 466                case AUDIT_SUBJ_USER:
 467                case AUDIT_SUBJ_ROLE:
 468                case AUDIT_SUBJ_TYPE:
 469                case AUDIT_SUBJ_SEN:
 470                case AUDIT_SUBJ_CLR:
 471                case AUDIT_OBJ_USER:
 472                case AUDIT_OBJ_ROLE:
 473                case AUDIT_OBJ_TYPE:
 474                case AUDIT_OBJ_LEV_LOW:
 475                case AUDIT_OBJ_LEV_HIGH:
 476                        str = audit_unpack_string(&bufp, &remain, f->val);
 477                        if (IS_ERR(str))
 478                                goto exit_free;
 479                        entry->rule.buflen += f->val;
 480
 481                        err = security_audit_rule_init(f->type, f->op, str,
 482                                                       (void **)&f->lsm_rule);
 483                        /* Keep currently invalid fields around in case they
 484                         * become valid after a policy reload. */
 485                        if (err == -EINVAL) {
 486                                printk(KERN_WARNING "audit rule for LSM "
 487                                       "\'%s\' is invalid\n",  str);
 488                                err = 0;
 489                        }
 490                        if (err) {
 491                                kfree(str);
 492                                goto exit_free;
 493                        } else
 494                                f->lsm_str = str;
 495                        break;
 496                case AUDIT_WATCH:
 497                        str = audit_unpack_string(&bufp, &remain, f->val);
 498                        if (IS_ERR(str))
 499                                goto exit_free;
 500                        entry->rule.buflen += f->val;
 501
 502                        err = audit_to_watch(&entry->rule, str, f->val, f->op);
 503                        if (err) {
 504                                kfree(str);
 505                                goto exit_free;
 506                        }
 507                        break;
 508                case AUDIT_DIR:
 509                        str = audit_unpack_string(&bufp, &remain, f->val);
 510                        if (IS_ERR(str))
 511                                goto exit_free;
 512                        entry->rule.buflen += f->val;
 513
 514                        err = audit_make_tree(&entry->rule, str, f->op);
 515                        kfree(str);
 516                        if (err)
 517                                goto exit_free;
 518                        break;
 519                case AUDIT_INODE:
 520                        err = audit_to_inode(&entry->rule, f);
 521                        if (err)
 522                                goto exit_free;
 523                        break;
 524                case AUDIT_FILTERKEY:
 525                        err = -EINVAL;
 526                        if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
 527                                goto exit_free;
 528                        str = audit_unpack_string(&bufp, &remain, f->val);
 529                        if (IS_ERR(str))
 530                                goto exit_free;
 531                        entry->rule.buflen += f->val;
 532                        entry->rule.filterkey = str;
 533                        break;
 534                case AUDIT_PERM:
 535                        if (f->val & ~15)
 536                                goto exit_free;
 537                        break;
 538                case AUDIT_FILETYPE:
 539                        if ((f->val & ~S_IFMT) > S_IFMT)
 540                                goto exit_free;
 541                        break;
 542                default:
 543                        goto exit_free;
 544                }
 545        }
 546
 547        if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
 548                entry->rule.inode_f = NULL;
 549
 550exit_nofree:
 551        return entry;
 552
 553exit_free:
 554        audit_free_rule(entry);
 555        return ERR_PTR(err);
 556}
 557
 558/* Pack a filter field's string representation into data block. */
 559static inline size_t audit_pack_string(void **bufp, const char *str)
 560{
 561        size_t len = strlen(str);
 562
 563        memcpy(*bufp, str, len);
 564        *bufp += len;
 565
 566        return len;
 567}
 568
 569/* Translate kernel rule respresentation to struct audit_rule.
 570 * Exists for backward compatibility with userspace. */
 571static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
 572{
 573        struct audit_rule *rule;
 574        int i;
 575
 576        rule = kzalloc(sizeof(*rule), GFP_KERNEL);
 577        if (unlikely(!rule))
 578                return NULL;
 579
 580        rule->flags = krule->flags | krule->listnr;
 581        rule->action = krule->action;
 582        rule->field_count = krule->field_count;
 583        for (i = 0; i < rule->field_count; i++) {
 584                rule->values[i] = krule->fields[i].val;
 585                rule->fields[i] = krule->fields[i].type;
 586
 587                if (krule->vers_ops == 1) {
 588                        if (krule->fields[i].op == Audit_not_equal)
 589                                rule->fields[i] |= AUDIT_NEGATE;
 590                } else {
 591                        rule->fields[i] |= audit_ops[krule->fields[i].op];
 592                }
 593        }
 594        for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
 595
 596        return rule;
 597}
 598
 599/* Translate kernel rule respresentation to struct audit_rule_data. */
 600static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
 601{
 602        struct audit_rule_data *data;
 603        void *bufp;
 604        int i;
 605
 606        data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
 607        if (unlikely(!data))
 608                return NULL;
 609        memset(data, 0, sizeof(*data));
 610
 611        data->flags = krule->flags | krule->listnr;
 612        data->action = krule->action;
 613        data->field_count = krule->field_count;
 614        bufp = data->buf;
 615        for (i = 0; i < data->field_count; i++) {
 616                struct audit_field *f = &krule->fields[i];
 617
 618                data->fields[i] = f->type;
 619                data->fieldflags[i] = audit_ops[f->op];
 620                switch(f->type) {
 621                case AUDIT_SUBJ_USER:
 622                case AUDIT_SUBJ_ROLE:
 623                case AUDIT_SUBJ_TYPE:
 624                case AUDIT_SUBJ_SEN:
 625                case AUDIT_SUBJ_CLR:
 626                case AUDIT_OBJ_USER:
 627                case AUDIT_OBJ_ROLE:
 628                case AUDIT_OBJ_TYPE:
 629                case AUDIT_OBJ_LEV_LOW:
 630                case AUDIT_OBJ_LEV_HIGH:
 631                        data->buflen += data->values[i] =
 632                                audit_pack_string(&bufp, f->lsm_str);
 633                        break;
 634                case AUDIT_WATCH:
 635                        data->buflen += data->values[i] =
 636                                audit_pack_string(&bufp,
 637                                                  audit_watch_path(krule->watch));
 638                        break;
 639                case AUDIT_DIR:
 640                        data->buflen += data->values[i] =
 641                                audit_pack_string(&bufp,
 642                                                  audit_tree_path(krule->tree));
 643                        break;
 644                case AUDIT_FILTERKEY:
 645                        data->buflen += data->values[i] =
 646                                audit_pack_string(&bufp, krule->filterkey);
 647                        break;
 648                default:
 649                        data->values[i] = f->val;
 650                }
 651        }
 652        for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
 653
 654        return data;
 655}
 656
 657/* Compare two rules in kernel format.  Considered success if rules
 658 * don't match. */
 659static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
 660{
 661        int i;
 662
 663        if (a->flags != b->flags ||
 664            a->listnr != b->listnr ||
 665            a->action != b->action ||
 666            a->field_count != b->field_count)
 667                return 1;
 668
 669        for (i = 0; i < a->field_count; i++) {
 670                if (a->fields[i].type != b->fields[i].type ||
 671                    a->fields[i].op != b->fields[i].op)
 672                        return 1;
 673
 674                switch(a->fields[i].type) {
 675                case AUDIT_SUBJ_USER:
 676                case AUDIT_SUBJ_ROLE:
 677                case AUDIT_SUBJ_TYPE:
 678                case AUDIT_SUBJ_SEN:
 679                case AUDIT_SUBJ_CLR:
 680                case AUDIT_OBJ_USER:
 681                case AUDIT_OBJ_ROLE:
 682                case AUDIT_OBJ_TYPE:
 683                case AUDIT_OBJ_LEV_LOW:
 684                case AUDIT_OBJ_LEV_HIGH:
 685                        if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
 686                                return 1;
 687                        break;
 688                case AUDIT_WATCH:
 689                        if (strcmp(audit_watch_path(a->watch),
 690                                   audit_watch_path(b->watch)))
 691                                return 1;
 692                        break;
 693                case AUDIT_DIR:
 694                        if (strcmp(audit_tree_path(a->tree),
 695                                   audit_tree_path(b->tree)))
 696                                return 1;
 697                        break;
 698                case AUDIT_FILTERKEY:
 699                        /* both filterkeys exist based on above type compare */
 700                        if (strcmp(a->filterkey, b->filterkey))
 701                                return 1;
 702                        break;
 703                default:
 704                        if (a->fields[i].val != b->fields[i].val)
 705                                return 1;
 706                }
 707        }
 708
 709        for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 710                if (a->mask[i] != b->mask[i])
 711                        return 1;
 712
 713        return 0;
 714}
 715
 716/* Duplicate LSM field information.  The lsm_rule is opaque, so must be
 717 * re-initialized. */
 718static inline int audit_dupe_lsm_field(struct audit_field *df,
 719                                           struct audit_field *sf)
 720{
 721        int ret = 0;
 722        char *lsm_str;
 723
 724        /* our own copy of lsm_str */
 725        lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
 726        if (unlikely(!lsm_str))
 727                return -ENOMEM;
 728        df->lsm_str = lsm_str;
 729
 730        /* our own (refreshed) copy of lsm_rule */
 731        ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
 732                                       (void **)&df->lsm_rule);
 733        /* Keep currently invalid fields around in case they
 734         * become valid after a policy reload. */
 735        if (ret == -EINVAL) {
 736                printk(KERN_WARNING "audit rule for LSM \'%s\' is "
 737                       "invalid\n", df->lsm_str);
 738                ret = 0;
 739        }
 740
 741        return ret;
 742}
 743
 744/* Duplicate an audit rule.  This will be a deep copy with the exception
 745 * of the watch - that pointer is carried over.  The LSM specific fields
 746 * will be updated in the copy.  The point is to be able to replace the old
 747 * rule with the new rule in the filterlist, then free the old rule.
 748 * The rlist element is undefined; list manipulations are handled apart from
 749 * the initial copy. */
 750struct audit_entry *audit_dupe_rule(struct audit_krule *old)
 751{
 752        u32 fcount = old->field_count;
 753        struct audit_entry *entry;
 754        struct audit_krule *new;
 755        char *fk;
 756        int i, err = 0;
 757
 758        entry = audit_init_entry(fcount);
 759        if (unlikely(!entry))
 760                return ERR_PTR(-ENOMEM);
 761
 762        new = &entry->rule;
 763        new->vers_ops = old->vers_ops;
 764        new->flags = old->flags;
 765        new->listnr = old->listnr;
 766        new->action = old->action;
 767        for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 768                new->mask[i] = old->mask[i];
 769        new->prio = old->prio;
 770        new->buflen = old->buflen;
 771        new->inode_f = old->inode_f;
 772        new->field_count = old->field_count;
 773
 774        /*
 775         * note that we are OK with not refcounting here; audit_match_tree()
 776         * never dereferences tree and we can't get false positives there
 777         * since we'd have to have rule gone from the list *and* removed
 778         * before the chunks found by lookup had been allocated, i.e. before
 779         * the beginning of list scan.
 780         */
 781        new->tree = old->tree;
 782        memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
 783
 784        /* deep copy this information, updating the lsm_rule fields, because
 785         * the originals will all be freed when the old rule is freed. */
 786        for (i = 0; i < fcount; i++) {
 787                switch (new->fields[i].type) {
 788                case AUDIT_SUBJ_USER:
 789                case AUDIT_SUBJ_ROLE:
 790                case AUDIT_SUBJ_TYPE:
 791                case AUDIT_SUBJ_SEN:
 792                case AUDIT_SUBJ_CLR:
 793                case AUDIT_OBJ_USER:
 794                case AUDIT_OBJ_ROLE:
 795                case AUDIT_OBJ_TYPE:
 796                case AUDIT_OBJ_LEV_LOW:
 797                case AUDIT_OBJ_LEV_HIGH:
 798                        err = audit_dupe_lsm_field(&new->fields[i],
 799                                                       &old->fields[i]);
 800                        break;
 801                case AUDIT_FILTERKEY:
 802                        fk = kstrdup(old->filterkey, GFP_KERNEL);
 803                        if (unlikely(!fk))
 804                                err = -ENOMEM;
 805                        else
 806                                new->filterkey = fk;
 807                }
 808                if (err) {
 809                        audit_free_rule(entry);
 810                        return ERR_PTR(err);
 811                }
 812        }
 813
 814        if (old->watch) {
 815                audit_get_watch(old->watch);
 816                new->watch = old->watch;
 817        }
 818
 819        return entry;
 820}
 821
 822/* Find an existing audit rule.
 823 * Caller must hold audit_filter_mutex to prevent stale rule data. */
 824static struct audit_entry *audit_find_rule(struct audit_entry *entry,
 825                                           struct list_head **p)
 826{
 827        struct audit_entry *e, *found = NULL;
 828        struct list_head *list;
 829        int h;
 830
 831        if (entry->rule.inode_f) {
 832                h = audit_hash_ino(entry->rule.inode_f->val);
 833                *p = list = &audit_inode_hash[h];
 834        } else if (entry->rule.watch) {
 835                /* we don't know the inode number, so must walk entire hash */
 836                for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
 837                        list = &audit_inode_hash[h];
 838                        list_for_each_entry(e, list, list)
 839                                if (!audit_compare_rule(&entry->rule, &e->rule)) {
 840                                        found = e;
 841                                        goto out;
 842                                }
 843                }
 844                goto out;
 845        } else {
 846                *p = list = &audit_filter_list[entry->rule.listnr];
 847        }
 848
 849        list_for_each_entry(e, list, list)
 850                if (!audit_compare_rule(&entry->rule, &e->rule)) {
 851                        found = e;
 852                        goto out;
 853                }
 854
 855out:
 856        return found;
 857}
 858
 859static u64 prio_low = ~0ULL/2;
 860static u64 prio_high = ~0ULL/2 - 1;
 861
 862/* Add rule to given filterlist if not a duplicate. */
 863static inline int audit_add_rule(struct audit_entry *entry)
 864{
 865        struct audit_entry *e;
 866        struct audit_watch *watch = entry->rule.watch;
 867        struct audit_tree *tree = entry->rule.tree;
 868        struct list_head *list;
 869        int err;
 870#ifdef CONFIG_AUDITSYSCALL
 871        int dont_count = 0;
 872
 873        /* If either of these, don't count towards total */
 874        if (entry->rule.listnr == AUDIT_FILTER_USER ||
 875                entry->rule.listnr == AUDIT_FILTER_TYPE)
 876                dont_count = 1;
 877#endif
 878
 879        mutex_lock(&audit_filter_mutex);
 880        e = audit_find_rule(entry, &list);
 881        if (e) {
 882                mutex_unlock(&audit_filter_mutex);
 883                err = -EEXIST;
 884                /* normally audit_add_tree_rule() will free it on failure */
 885                if (tree)
 886                        audit_put_tree(tree);
 887                goto error;
 888        }
 889
 890        if (watch) {
 891                /* audit_filter_mutex is dropped and re-taken during this call */
 892                err = audit_add_watch(&entry->rule, &list);
 893                if (err) {
 894                        mutex_unlock(&audit_filter_mutex);
 895                        goto error;
 896                }
 897        }
 898        if (tree) {
 899                err = audit_add_tree_rule(&entry->rule);
 900                if (err) {
 901                        mutex_unlock(&audit_filter_mutex);
 902                        goto error;
 903                }
 904        }
 905
 906        entry->rule.prio = ~0ULL;
 907        if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
 908                if (entry->rule.flags & AUDIT_FILTER_PREPEND)
 909                        entry->rule.prio = ++prio_high;
 910                else
 911                        entry->rule.prio = --prio_low;
 912        }
 913
 914        if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
 915                list_add(&entry->rule.list,
 916                         &audit_rules_list[entry->rule.listnr]);
 917                list_add_rcu(&entry->list, list);
 918                entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
 919        } else {
 920                list_add_tail(&entry->rule.list,
 921                              &audit_rules_list[entry->rule.listnr]);
 922                list_add_tail_rcu(&entry->list, list);
 923        }
 924#ifdef CONFIG_AUDITSYSCALL
 925        if (!dont_count)
 926                audit_n_rules++;
 927
 928        if (!audit_match_signal(entry))
 929                audit_signals++;
 930#endif
 931        mutex_unlock(&audit_filter_mutex);
 932
 933        return 0;
 934
 935error:
 936        if (watch)
 937                audit_put_watch(watch); /* tmp watch, matches initial get */
 938        return err;
 939}
 940
 941/* Remove an existing rule from filterlist. */
 942static inline int audit_del_rule(struct audit_entry *entry)
 943{
 944        struct audit_entry  *e;
 945        struct audit_watch *watch = entry->rule.watch;
 946        struct audit_tree *tree = entry->rule.tree;
 947        struct list_head *list;
 948        int ret = 0;
 949#ifdef CONFIG_AUDITSYSCALL
 950        int dont_count = 0;
 951
 952        /* If either of these, don't count towards total */
 953        if (entry->rule.listnr == AUDIT_FILTER_USER ||
 954                entry->rule.listnr == AUDIT_FILTER_TYPE)
 955                dont_count = 1;
 956#endif
 957
 958        mutex_lock(&audit_filter_mutex);
 959        e = audit_find_rule(entry, &list);
 960        if (!e) {
 961                mutex_unlock(&audit_filter_mutex);
 962                ret = -ENOENT;
 963                goto out;
 964        }
 965
 966        if (e->rule.watch)
 967                audit_remove_watch_rule(&e->rule);
 968
 969        if (e->rule.tree)
 970                audit_remove_tree_rule(&e->rule);
 971
 972        list_del_rcu(&e->list);
 973        list_del(&e->rule.list);
 974        call_rcu(&e->rcu, audit_free_rule_rcu);
 975
 976#ifdef CONFIG_AUDITSYSCALL
 977        if (!dont_count)
 978                audit_n_rules--;
 979
 980        if (!audit_match_signal(entry))
 981                audit_signals--;
 982#endif
 983        mutex_unlock(&audit_filter_mutex);
 984
 985out:
 986        if (watch)
 987                audit_put_watch(watch); /* match initial get */
 988        if (tree)
 989                audit_put_tree(tree);   /* that's the temporary one */
 990
 991        return ret;
 992}
 993
 994/* List rules using struct audit_rule.  Exists for backward
 995 * compatibility with userspace. */
 996static void audit_list(int pid, int seq, struct sk_buff_head *q)
 997{
 998        struct sk_buff *skb;
 999        struct audit_krule *r;
1000        int i;
1001
1002        /* This is a blocking read, so use audit_filter_mutex instead of rcu
1003         * iterator to sync with list writers. */
1004        for (i=0; i<AUDIT_NR_FILTERS; i++) {
1005                list_for_each_entry(r, &audit_rules_list[i], list) {
1006                        struct audit_rule *rule;
1007
1008                        rule = audit_krule_to_rule(r);
1009                        if (unlikely(!rule))
1010                                break;
1011                        skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1012                                         rule, sizeof(*rule));
1013                        if (skb)
1014                                skb_queue_tail(q, skb);
1015                        kfree(rule);
1016                }
1017        }
1018        skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1019        if (skb)
1020                skb_queue_tail(q, skb);
1021}
1022
1023/* List rules using struct audit_rule_data. */
1024static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1025{
1026        struct sk_buff *skb;
1027        struct audit_krule *r;
1028        int i;
1029
1030        /* This is a blocking read, so use audit_filter_mutex instead of rcu
1031         * iterator to sync with list writers. */
1032        for (i=0; i<AUDIT_NR_FILTERS; i++) {
1033                list_for_each_entry(r, &audit_rules_list[i], list) {
1034                        struct audit_rule_data *data;
1035
1036                        data = audit_krule_to_data(r);
1037                        if (unlikely(!data))
1038                                break;
1039                        skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1040                                         data, sizeof(*data) + data->buflen);
1041                        if (skb)
1042                                skb_queue_tail(q, skb);
1043                        kfree(data);
1044                }
1045        }
1046        skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1047        if (skb)
1048                skb_queue_tail(q, skb);
1049}
1050
1051/* Log rule additions and removals */
1052static void audit_log_rule_change(uid_t loginuid, u32 sessionid, u32 sid,
1053                                  char *action, struct audit_krule *rule,
1054                                  int res)
1055{
1056        struct audit_buffer *ab;
1057
1058        if (!audit_enabled)
1059                return;
1060
1061        ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1062        if (!ab)
1063                return;
1064        audit_log_format(ab, "auid=%u ses=%u", loginuid, sessionid);
1065        if (sid) {
1066                char *ctx = NULL;
1067                u32 len;
1068                if (security_secid_to_secctx(sid, &ctx, &len))
1069                        audit_log_format(ab, " ssid=%u", sid);
1070                else {
1071                        audit_log_format(ab, " subj=%s", ctx);
1072                        security_release_secctx(ctx, len);
1073                }
1074        }
1075        audit_log_format(ab, " op=");
1076        audit_log_string(ab, action);
1077        audit_log_key(ab, rule->filterkey);
1078        audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1079        audit_log_end(ab);
1080}
1081
1082/**
1083 * audit_receive_filter - apply all rules to the specified message type
1084 * @type: audit message type
1085 * @pid: target pid for netlink audit messages
1086 * @uid: target uid for netlink audit messages
1087 * @seq: netlink audit message sequence (serial) number
1088 * @data: payload data
1089 * @datasz: size of payload data
1090 * @loginuid: loginuid of sender
1091 * @sessionid: sessionid for netlink audit message
1092 * @sid: SE Linux Security ID of sender
1093 */
1094int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1095                         size_t datasz, uid_t loginuid, u32 sessionid, u32 sid)
1096{
1097        struct task_struct *tsk;
1098        struct audit_netlink_list *dest;
1099        int err = 0;
1100        struct audit_entry *entry;
1101
1102        switch (type) {
1103        case AUDIT_LIST:
1104        case AUDIT_LIST_RULES:
1105                /* We can't just spew out the rules here because we might fill
1106                 * the available socket buffer space and deadlock waiting for
1107                 * auditctl to read from it... which isn't ever going to
1108                 * happen if we're actually running in the context of auditctl
1109                 * trying to _send_ the stuff */
1110
1111                dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1112                if (!dest)
1113                        return -ENOMEM;
1114                dest->pid = pid;
1115                skb_queue_head_init(&dest->q);
1116
1117                mutex_lock(&audit_filter_mutex);
1118                if (type == AUDIT_LIST)
1119                        audit_list(pid, seq, &dest->q);
1120                else
1121                        audit_list_rules(pid, seq, &dest->q);
1122                mutex_unlock(&audit_filter_mutex);
1123
1124                tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1125                if (IS_ERR(tsk)) {
1126                        skb_queue_purge(&dest->q);
1127                        kfree(dest);
1128                        err = PTR_ERR(tsk);
1129                }
1130                break;
1131        case AUDIT_ADD:
1132        case AUDIT_ADD_RULE:
1133                if (type == AUDIT_ADD)
1134                        entry = audit_rule_to_entry(data);
1135                else
1136                        entry = audit_data_to_entry(data, datasz);
1137                if (IS_ERR(entry))
1138                        return PTR_ERR(entry);
1139
1140                err = audit_add_rule(entry);
1141                audit_log_rule_change(loginuid, sessionid, sid, "add rule",
1142                                      &entry->rule, !err);
1143
1144                if (err)
1145                        audit_free_rule(entry);
1146                break;
1147        case AUDIT_DEL:
1148        case AUDIT_DEL_RULE:
1149                if (type == AUDIT_DEL)
1150                        entry = audit_rule_to_entry(data);
1151                else
1152                        entry = audit_data_to_entry(data, datasz);
1153                if (IS_ERR(entry))
1154                        return PTR_ERR(entry);
1155
1156                err = audit_del_rule(entry);
1157                audit_log_rule_change(loginuid, sessionid, sid, "remove rule",
1158                                      &entry->rule, !err);
1159
1160                audit_free_rule(entry);
1161                break;
1162        default:
1163                return -EINVAL;
1164        }
1165
1166        return err;
1167}
1168
1169int audit_comparator(u32 left, u32 op, u32 right)
1170{
1171        switch (op) {
1172        case Audit_equal:
1173                return (left == right);
1174        case Audit_not_equal:
1175                return (left != right);
1176        case Audit_lt:
1177                return (left < right);
1178        case Audit_le:
1179                return (left <= right);
1180        case Audit_gt:
1181                return (left > right);
1182        case Audit_ge:
1183                return (left >= right);
1184        case Audit_bitmask:
1185                return (left & right);
1186        case Audit_bittest:
1187                return ((left & right) == right);
1188        default:
1189                BUG();
1190                return 0;
1191        }
1192}
1193
1194/* Compare given dentry name with last component in given path,
1195 * return of 0 indicates a match. */
1196int audit_compare_dname_path(const char *dname, const char *path,
1197                             int *dirlen)
1198{
1199        int dlen, plen;
1200        const char *p;
1201
1202        if (!dname || !path)
1203                return 1;
1204
1205        dlen = strlen(dname);
1206        plen = strlen(path);
1207        if (plen < dlen)
1208                return 1;
1209
1210        /* disregard trailing slashes */
1211        p = path + plen - 1;
1212        while ((*p == '/') && (p > path))
1213                p--;
1214
1215        /* find last path component */
1216        p = p - dlen + 1;
1217        if (p < path)
1218                return 1;
1219        else if (p > path) {
1220                if (*--p != '/')
1221                        return 1;
1222                else
1223                        p++;
1224        }
1225
1226        /* return length of path's directory component */
1227        if (dirlen)
1228                *dirlen = p - path;
1229        return strncmp(p, dname, dlen);
1230}
1231
1232static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1233                                   struct audit_krule *rule,
1234                                   enum audit_state *state)
1235{
1236        int i;
1237
1238        for (i = 0; i < rule->field_count; i++) {
1239                struct audit_field *f = &rule->fields[i];
1240                int result = 0;
1241                u32 sid;
1242
1243                switch (f->type) {
1244                case AUDIT_PID:
1245                        result = audit_comparator(cb->creds.pid, f->op, f->val);
1246                        break;
1247                case AUDIT_UID:
1248                        result = audit_comparator(cb->creds.uid, f->op, f->val);
1249                        break;
1250                case AUDIT_GID:
1251                        result = audit_comparator(cb->creds.gid, f->op, f->val);
1252                        break;
1253                case AUDIT_LOGINUID:
1254                        result = audit_comparator(audit_get_loginuid(current),
1255                                                  f->op, f->val);
1256                        break;
1257                case AUDIT_SUBJ_USER:
1258                case AUDIT_SUBJ_ROLE:
1259                case AUDIT_SUBJ_TYPE:
1260                case AUDIT_SUBJ_SEN:
1261                case AUDIT_SUBJ_CLR:
1262                        if (f->lsm_rule) {
1263                                security_task_getsecid(current, &sid);
1264                                result = security_audit_rule_match(sid,
1265                                                                   f->type,
1266                                                                   f->op,
1267                                                                   f->lsm_rule,
1268                                                                   NULL);
1269                        }
1270                        break;
1271                }
1272
1273                if (!result)
1274                        return 0;
1275        }
1276        switch (rule->action) {
1277        case AUDIT_NEVER:    *state = AUDIT_DISABLED;       break;
1278        case AUDIT_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
1279        }
1280        return 1;
1281}
1282
1283int audit_filter_user(struct netlink_skb_parms *cb)
1284{
1285        enum audit_state state = AUDIT_DISABLED;
1286        struct audit_entry *e;
1287        int ret = 1;
1288
1289        rcu_read_lock();
1290        list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1291                if (audit_filter_user_rules(cb, &e->rule, &state)) {
1292                        if (state == AUDIT_DISABLED)
1293                                ret = 0;
1294                        break;
1295                }
1296        }
1297        rcu_read_unlock();
1298
1299        return ret; /* Audit by default */
1300}
1301
1302int audit_filter_type(int type)
1303{
1304        struct audit_entry *e;
1305        int result = 0;
1306
1307        rcu_read_lock();
1308        if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1309                goto unlock_and_return;
1310
1311        list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1312                                list) {
1313                int i;
1314                for (i = 0; i < e->rule.field_count; i++) {
1315                        struct audit_field *f = &e->rule.fields[i];
1316                        if (f->type == AUDIT_MSGTYPE) {
1317                                result = audit_comparator(type, f->op, f->val);
1318                                if (!result)
1319                                        break;
1320                        }
1321                }
1322                if (result)
1323                        goto unlock_and_return;
1324        }
1325unlock_and_return:
1326        rcu_read_unlock();
1327        return result;
1328}
1329
1330static int update_lsm_rule(struct audit_krule *r)
1331{
1332        struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1333        struct audit_entry *nentry;
1334        int err = 0;
1335
1336        if (!security_audit_rule_known(r))
1337                return 0;
1338
1339        nentry = audit_dupe_rule(r);
1340        if (IS_ERR(nentry)) {
1341                /* save the first error encountered for the
1342                 * return value */
1343                err = PTR_ERR(nentry);
1344                audit_panic("error updating LSM filters");
1345                if (r->watch)
1346                        list_del(&r->rlist);
1347                list_del_rcu(&entry->list);
1348                list_del(&r->list);
1349        } else {
1350                if (r->watch || r->tree)
1351                        list_replace_init(&r->rlist, &nentry->rule.rlist);
1352                list_replace_rcu(&entry->list, &nentry->list);
1353                list_replace(&r->list, &nentry->rule.list);
1354        }
1355        call_rcu(&entry->rcu, audit_free_rule_rcu);
1356
1357        return err;
1358}
1359
1360/* This function will re-initialize the lsm_rule field of all applicable rules.
1361 * It will traverse the filter lists serarching for rules that contain LSM
1362 * specific filter fields.  When such a rule is found, it is copied, the
1363 * LSM field is re-initialized, and the old rule is replaced with the
1364 * updated rule. */
1365int audit_update_lsm_rules(void)
1366{
1367        struct audit_krule *r, *n;
1368        int i, err = 0;
1369
1370        /* audit_filter_mutex synchronizes the writers */
1371        mutex_lock(&audit_filter_mutex);
1372
1373        for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1374                list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1375                        int res = update_lsm_rule(r);
1376                        if (!err)
1377                                err = res;
1378                }
1379        }
1380        mutex_unlock(&audit_filter_mutex);
1381
1382        return err;
1383}
1384
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