contrib/openbsm/bin/auditdistd/trail.c

   1 /*-
   2  * Copyright (c) 2012 The FreeBSD Foundation
   3  * All rights reserved.
   4  *
   5  * This software was developed by Pawel Jakub Dawidek under sponsorship from
   6  * the FreeBSD Foundation.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #include <config/config.h>
  31
  32 #include <sys/param.h>
  33 #include <sys/stat.h>
  34
  35 #include <dirent.h>
  36 #include <errno.h>
  37 #include <fcntl.h>
  38 #include <stdbool.h>
  39 #include <stdint.h>
  40 #include <stdlib.h>
  41 #include <string.h>
  42 #include <unistd.h>
  43
  44 #include <compat/compat.h>
  45 #ifndef HAVE_STRLCPY
  46 #include <compat/strlcpy.h>
  47 #endif
  48 #ifndef HAVE_FACCESSAT
  49 #include "faccessat.h"
  50 #endif
  51 #ifndef HAVE_FSTATAT
  52 #include "fstatat.h"
  53 #endif
  54 #ifndef HAVE_OPENAT
  55 #include "openat.h"
  56 #endif
  57 #ifndef HAVE_UNLINKAT
  58 #include "unlinkat.h"
  59 #endif
  60
  61 #include "pjdlog.h"
  62 #include "trail.h"
  63
  64 #define TRAIL_MAGIC     0x79a11
  65 struct trail {
  66         int      tr_magic;
  67         /* Path usually to /var/audit/dist/ directory. */
  68         char     tr_dirname[PATH_MAX];
  69         /* Descriptor to td_dirname directory. */
  70         DIR     *tr_dirfp;
  71         /* Path to audit trail file. */
  72         char     tr_filename[PATH_MAX];
  73         /* Descriptor to audit trail file. */
  74         int      tr_filefd;
  75 };
  76
  77 #define HALF_LEN        14
  78
  79 bool
  80 trail_is_not_terminated(const char *filename)
  81 {
  82
  83         return (strcmp(filename + HALF_LEN, ".not_terminated") == 0);
  84 }
  85
  86 bool
  87 trail_is_crash_recovery(const char *filename)
  88 {
  89
  90         return (strcmp(filename + HALF_LEN, ".crash_recovery") == 0);
  91 }
  92
  93 struct trail *
  94 trail_new(const char *dirname, bool create)
  95 {
  96         struct trail *trail;
  97
  98         trail = calloc(1, sizeof(*trail));
  99
 100         if (strlcpy(trail->tr_dirname, dirname, sizeof(trail->tr_dirname)) >=
 101             sizeof(trail->tr_dirname)) {
 102                 free(trail);
 103                 pjdlog_error("Directory name too long (\"%s\").", dirname);
 104                 errno = ENAMETOOLONG;
 105                 return (NULL);
 106         }
 107         trail->tr_dirfp = opendir(dirname);
 108         if (trail->tr_dirfp == NULL) {
 109                 if (create && errno == ENOENT) {
 110                         if (mkdir(dirname, 0700) == -1) {
 111                                 pjdlog_errno(LOG_ERR,
 112                                     "Unable to create directory \"%s\"",
 113                                     dirname);
 114                                 free(trail);
 115                                 return (NULL);
 116                         }
 117                         /* TODO: Set directory ownership. */
 118                 } else {
 119                         pjdlog_errno(LOG_ERR,
 120                             "Unable to open directory \"%s\"",
 121                             dirname);
 122                         free(trail);
 123                         return (NULL);
 124                 }
 125                 trail->tr_dirfp = opendir(dirname);
 126                 if (trail->tr_dirfp == NULL) {
 127                         pjdlog_errno(LOG_ERR,
 128                             "Unable to open directory \"%s\"",
 129                             dirname);
 130                         free(trail);
 131                         return (NULL);
 132                 }
 133         }
 134         trail->tr_filefd = -1;
 135         trail->tr_magic = TRAIL_MAGIC;
 136         return (trail);
 137 }
 138
 139 void
 140 trail_free(struct trail *trail)
 141 {
 142
 143         PJDLOG_ASSERT(trail->tr_magic == TRAIL_MAGIC);
 144
 145         if (trail->tr_filefd != -1)
 146                 trail_close(trail);
 147         closedir(trail->tr_dirfp);
 148         bzero(trail, sizeof(*trail));
 149         trail->tr_magic = 0;
 150         trail->tr_filefd = -1;
 151         free(trail);
 152 }
 153
 154 static uint8_t
 155 trail_type(DIR *dirfp, const char *filename)
 156 {
 157         struct stat sb;
 158         int dfd;
 159
 160         PJDLOG_ASSERT(dirfp != NULL);
 161
 162         dfd = dirfd(dirfp);
 163         PJDLOG_ASSERT(dfd >= 0);
 164         if (fstatat(dfd, filename, &sb, AT_SYMLINK_NOFOLLOW) == -1) {
 165                 pjdlog_errno(LOG_ERR, "Unable to stat \"%s\"", filename);
 166                 return (DT_UNKNOWN);
 167         }
 168         return (IFTODT(sb.st_mode));
 169 }
 170
 171 /*
 172  * Find trail file by first part of the name in case it was renamed.
 173  * First part of the trail file name never changes, but trail file
 174  * can be renamed when hosts are disconnected from .not_terminated
 175  * to .[0-9]{14} or to .crash_recovery.
 176  */
 177 static bool
 178 trail_find(struct trail *trail)
 179 {
 180         struct dirent *dp;
 181
 182         PJDLOG_ASSERT(trail->tr_magic == TRAIL_MAGIC);
 183         PJDLOG_ASSERT(trail_is_not_terminated(trail->tr_filename));
 184
 185         rewinddir(trail->tr_dirfp);
 186         while ((dp = readdir(trail->tr_dirfp)) != NULL) {
 187                 if (strncmp(dp->d_name, trail->tr_filename, HALF_LEN + 1) == 0)
 188                         break;
 189         }
 190         if (dp == NULL)
 191                 return (false);
 192         PJDLOG_VERIFY(strlcpy(trail->tr_filename, dp->d_name,
 193             sizeof(trail->tr_filename)) < sizeof(trail->tr_filename));
 194         return (true);
 195 }
 196
 197 /*
 198  * Open the given trail file and move pointer at the given offset, as this is
 199  * where receiver finished the last time.
 200  * If the file doesn't exist or the given offset is equal to the file size,
 201  * move to the next trail file.
 202  */
 203 void
 204 trail_start(struct trail *trail, const char *filename, off_t offset)
 205 {
 206         struct stat sb;
 207         int dfd, fd;
 208
 209         PJDLOG_ASSERT(trail->tr_magic == TRAIL_MAGIC);
 210
 211         PJDLOG_VERIFY(strlcpy(trail->tr_filename, filename,
 212             sizeof(trail->tr_filename)) < sizeof(trail->tr_filename));
 213         trail->tr_filefd = -1;
 214
 215         if (trail->tr_filename[0] == '\0') {
 216                 PJDLOG_ASSERT(offset == 0);
 217                 trail_next(trail);
 218                 return;
 219         }
 220
 221         dfd = dirfd(trail->tr_dirfp);
 222         PJDLOG_ASSERT(dfd >= 0);
 223 again:
 224         fd = openat(dfd, trail->tr_filename, O_RDONLY);
 225         if (fd == -1) {
 226                 if (errno == ENOENT &&
 227                     trail_is_not_terminated(trail->tr_filename) &&
 228                     trail_find(trail)) {
 229                         /* File was renamed. Retry with new name. */
 230                         pjdlog_debug(1,
 231                            "Trail file was renamed since last connection to \"%s/%s\".",
 232                            trail->tr_dirname, trail->tr_filename);
 233                         goto again;
 234                 } else if (errno == ENOENT) {
 235                         /* File disappeared. */
 236                         pjdlog_debug(1, "File \"%s/%s\" doesn't exist.",
 237                             trail->tr_dirname, trail->tr_filename);
 238                 } else {
 239                         pjdlog_errno(LOG_ERR,
 240                             "Unable to open file \"%s/%s\", skipping",
 241                             trail->tr_dirname, trail->tr_filename);
 242                 }
 243                 trail_next(trail);
 244                 return;
 245         }
 246         if (fstat(fd, &sb) == -1) {
 247                 pjdlog_errno(LOG_ERR,
 248                     "Unable to stat file \"%s/%s\", skipping",
 249                     trail->tr_dirname, trail->tr_filename);
 250                 close(fd);
 251                 trail_next(trail);
 252                 return;
 253         }
 254         if (!S_ISREG(sb.st_mode)) {
 255                 pjdlog_warning("File \"%s/%s\" is not a regular file, skipping.",
 256                     trail->tr_dirname, trail->tr_filename);
 257                 close(fd);
 258                 trail_next(trail);
 259                 return;
 260         }
 261         /*
 262          * We continue sending requested file if:
 263          * 1. It is not fully sent yet, or
 264          * 2. It is fully sent, but is not terminated, so new data can be
 265          *    appended still, or
 266          * 3. It is fully sent but file name has changed.
 267          *
 268          * Note that we are fine if our .not_terminated or .crash_recovery file
 269          * is smaller than the one on the receiver side, as it is possible that
 270          * more data was send to the receiver than was safely stored on disk.
 271          * We accept .not_terminated only because auditdistd can start before
 272          * auditd manage to rename it to .crash_recovery.
 273          */
 274         if (offset < sb.st_size ||
 275             (offset >= sb.st_size &&
 276              trail_is_not_terminated(trail->tr_filename)) ||
 277             (offset >= sb.st_size && trail_is_not_terminated(filename) &&
 278              trail_is_crash_recovery(trail->tr_filename))) {
 279                 /* File was not fully send. Let's finish it. */
 280                 if (lseek(fd, offset, SEEK_SET) == -1) {
 281                         pjdlog_errno(LOG_ERR,
 282                             "Unable to move to offset %jd within file \"%s/%s\", skipping",
 283                             (intmax_t)offset, trail->tr_dirname,
 284                             trail->tr_filename);
 285                         close(fd);
 286                         trail_next(trail);
 287                         return;
 288                 }
 289                 if (!trail_is_crash_recovery(trail->tr_filename)) {
 290                         pjdlog_debug(1,
 291                             "Restarting file \"%s/%s\" at offset %jd.",
 292                             trail->tr_dirname, trail->tr_filename,
 293                             (intmax_t)offset);
 294                 }
 295                 trail->tr_filefd = fd;
 296                 return;
 297         }
 298         close(fd);
 299         if (offset > sb.st_size) {
 300                 pjdlog_warning("File \"%s/%s\" shrinked, removing it.",
 301                     trail->tr_dirname, trail->tr_filename);
 302         } else {
 303                 pjdlog_debug(1, "File \"%s/%s\" is already sent, removing it.",
 304                     trail->tr_dirname, trail->tr_filename);
 305         }
 306         /* Entire file is already sent or it shirnked, we can remove it. */
 307         if (unlinkat(dfd, trail->tr_filename, 0) == -1) {
 308                 pjdlog_errno(LOG_WARNING, "Unable to remove file \"%s/%s\"",
 309                     trail->tr_dirname, trail->tr_filename);
 310         }
 311         trail_next(trail);
 312 }
 313
 314 /*
 315  * Set next file in the trail->tr_dirname directory and open it for reading.
 316  */
 317 void
 318 trail_next(struct trail *trail)
 319 {
 320         char curfile[PATH_MAX];
 321         struct dirent *dp;
 322         int dfd;
 323
 324         PJDLOG_ASSERT(trail->tr_magic == TRAIL_MAGIC);
 325         PJDLOG_ASSERT(trail->tr_filefd == -1);
 326
 327 again:
 328         curfile[0] = '\0';
 329
 330         rewinddir(trail->tr_dirfp);
 331         while ((dp = readdir(trail->tr_dirfp)) != NULL) {
 332                 if (dp->d_name[0] < '0' || dp->d_name[0] > '9')
 333                         continue;
 334                 if (dp->d_type == DT_UNKNOWN)
 335                         dp->d_type = trail_type(trail->tr_dirfp, dp->d_name);
 336                 /* We are only interested in regular files, skip the rest. */
 337                 if (dp->d_type != DT_REG) {
 338                         pjdlog_debug(1,
 339                             "File \"%s/%s\" is not a regular file, skipping.",
 340                             trail->tr_dirname, dp->d_name);
 341                         continue;
 342                 }
 343                 /* Skip all files "greater" than curfile. */
 344                 if (curfile[0] != '\0' && strcmp(dp->d_name, curfile) > 0)
 345                         continue;
 346                 /* Skip all files "smaller" than the current trail_filename. */
 347                 if (trail->tr_filename[0] != '\0' &&
 348                     strcmp(dp->d_name, trail->tr_filename) <= 0) {
 349                         continue;
 350                 }
 351                 PJDLOG_VERIFY(strlcpy(curfile, dp->d_name, sizeof(curfile)) <
 352                     sizeof(curfile));
 353         }
 354         if (curfile[0] == '\0') {
 355                 /*
 356                  * There are no new trail files, so we return.
 357                  * We don't clear trail_filename string, to know where to
 358                  * start when new file appears.
 359                  */
 360                 PJDLOG_ASSERT(trail->tr_filefd == -1);
 361                 pjdlog_debug(1, "No new trail files.");
 362                 return;
 363         }
 364         PJDLOG_VERIFY(strlcpy(trail->tr_filename, curfile,
 365             sizeof(trail->tr_filename)) < sizeof(trail->tr_filename));
 366         dfd = dirfd(trail->tr_dirfp);
 367         PJDLOG_ASSERT(dfd >= 0);
 368         trail->tr_filefd = openat(dfd, trail->tr_filename, O_RDONLY);
 369         if (trail->tr_filefd == -1) {
 370                 pjdlog_errno(LOG_ERR,
 371                     "Unable to open file \"%s/%s\", skipping",
 372                     trail->tr_dirname, trail->tr_filename);
 373                 goto again;
 374         }
 375         pjdlog_debug(1, "Found next trail file: \"%s/%s\".", trail->tr_dirname,
 376             trail->tr_filename);
 377 }
 378
 379 /*
 380  * Close current trial file.
 381  */
 382 void
 383 trail_close(struct trail *trail)
 384 {
 385
 386         PJDLOG_ASSERT(trail->tr_magic == TRAIL_MAGIC);
 387         PJDLOG_ASSERT(trail->tr_filefd >= 0);
 388         PJDLOG_ASSERT(trail->tr_filename[0] != '\0');
 389
 390         PJDLOG_VERIFY(close(trail->tr_filefd) == 0);
 391         trail->tr_filefd = -1;
 392 }
 393
 394 /*
 395  * Reset trail state. Used when connection is disconnected and we will
 396  * need to start over after reconnect. Trail needs to be already closed.
 397  */
 398 void
 399 trail_reset(struct trail *trail)
 400 {
 401
 402         PJDLOG_ASSERT(trail->tr_magic == TRAIL_MAGIC);
 403         PJDLOG_ASSERT(trail->tr_filefd == -1);
 404
 405         trail->tr_filename[0] = '\0';
 406 }
 407
 408 /*
 409  * Unlink current trial file.
 410  */
 411 void
 412 trail_unlink(struct trail *trail, const char *filename)
 413 {
 414         int dfd;
 415
 416         PJDLOG_ASSERT(trail->tr_magic == TRAIL_MAGIC);
 417         PJDLOG_ASSERT(filename != NULL);
 418         PJDLOG_ASSERT(filename[0] != '\0');
 419
 420         dfd = dirfd(trail->tr_dirfp);
 421         PJDLOG_ASSERT(dfd >= 0);
 422
 423         if (unlinkat(dfd, filename, 0) == -1) {
 424                 pjdlog_errno(LOG_ERR, "Unable to remove \"%s/%s\"",
 425                     trail->tr_dirname, filename);
 426         } else {
 427                 pjdlog_debug(1, "Trail file \"%s/%s\" removed.",
 428                     trail->tr_dirname, filename);
 429         }
 430 }
 431
 432 /*
 433  * Return true if we should switch to next trail file.
 434  * We don't switch if our file name ends with ".not_terminated" and it
 435  * exists (ie. wasn't renamed).
 436  */
 437 bool
 438 trail_switch(struct trail *trail)
 439 {
 440         char filename[PATH_MAX];
 441         int fd;
 442
 443         PJDLOG_ASSERT(trail->tr_magic == TRAIL_MAGIC);
 444         PJDLOG_ASSERT(trail->tr_filefd >= 0);
 445
 446         if (!trail_is_not_terminated(trail->tr_filename))
 447                 return (true);
 448         fd = dirfd(trail->tr_dirfp);
 449         PJDLOG_ASSERT(fd >= 0);
 450         if (faccessat(fd, trail->tr_filename, F_OK, 0) == 0)
 451                 return (false);
 452         if (errno != ENOENT) {
 453                 pjdlog_errno(LOG_ERR, "Unable to access file \"%s/%s\"",
 454                     trail->tr_dirname, trail->tr_filename);
 455         }
 456         strlcpy(filename, trail->tr_filename, sizeof(filename));
 457         if (!trail_find(trail)) {
 458                 pjdlog_error("Trail file \"%s/%s\" disappeared.",
 459                     trail->tr_dirname, trail->tr_filename);
 460                 return (true);
 461         }
 462         pjdlog_debug(1, "Trail file \"%s/%s\" was renamed to \"%s/%s\".",
 463             trail->tr_dirname, filename, trail->tr_dirname,
 464             trail->tr_filename);
 465         return (true);
 466 }
 467
 468 const char *
 469 trail_filename(const struct trail *trail)
 470 {
 471
 472         PJDLOG_ASSERT(trail->tr_magic == TRAIL_MAGIC);
 473
 474         return (trail->tr_filename);
 475 }
 476
 477 int
 478 trail_filefd(const struct trail *trail)
 479 {
 480
 481         PJDLOG_ASSERT(trail->tr_magic == TRAIL_MAGIC);
 482
 483         return (trail->tr_filefd);
 484 }
 485
 486 int
 487 trail_dirfd(const struct trail *trail)
 488 {
 489
 490         PJDLOG_ASSERT(trail->tr_magic == TRAIL_MAGIC);
 491
 492         return (dirfd(trail->tr_dirfp));
 493 }
 494
 495 /*
 496  * Find the last file in the directory opened under dirfp.
 497  */
 498 void
 499 trail_last(DIR *dirfp, char *filename, size_t filenamesize)
 500 {
 501         char curfile[PATH_MAX];
 502         struct dirent *dp;
 503
 504         PJDLOG_ASSERT(dirfp != NULL);
 505
 506         curfile[0] = '\0';
 507
 508         rewinddir(dirfp);
 509         while ((dp = readdir(dirfp)) != NULL) {
 510                 if (dp->d_name[0] < '0' || dp->d_name[0] > '9')
 511                         continue;
 512                 if (dp->d_type == DT_UNKNOWN)
 513                         dp->d_type = trail_type(dirfp, dp->d_name);
 514                 /* We are only interested in regular files, skip the rest. */
 515                 if (dp->d_type != DT_REG)
 516                         continue;
 517                 /* Skip all files "greater" than curfile. */
 518                 if (curfile[0] != '\0' && strcmp(dp->d_name, curfile) < 0)
 519                         continue;
 520                 PJDLOG_VERIFY(strlcpy(curfile, dp->d_name, sizeof(curfile)) <
 521                     sizeof(curfile));
 522         }
 523         if (curfile[0] == '\0') {
 524                 /*
 525                  * There are no trail files, so we return.
 526                  */
 527                 pjdlog_debug(1, "No trail files.");
 528                 bzero(filename, filenamesize);
 529                 return;
 530         }
 531         PJDLOG_VERIFY(strlcpy(filename, curfile, filenamesize) < filenamesize);
 532         pjdlog_debug(1, "Found the most recent trail file: \"%s\".", filename);
 533 }
 534
 535 /*
 536  * Check if the given file name is a valid audit trail file name.
 537  * Possible names:
 538  * 20120106132657.20120106132805
 539  * 20120106132657.not_terminated
 540  * 20120106132657.crash_recovery
 541  * If two names are given, check if the first name can be renamed
 542  * to the second name. When renaming, first part of the name has
 543  * to be identical and only the following renames are valid:
 544  * 20120106132657.not_terminated -> 20120106132657.20120106132805
 545  * 20120106132657.not_terminated -> 20120106132657.crash_recovery
 546  */
 547 bool
 548 trail_validate_name(const char *srcname, const char *dstname)
 549 {
 550         int i;
 551
 552         PJDLOG_ASSERT(srcname != NULL);
 553
 554         if (strlen(srcname) != 2 * HALF_LEN + 1)
 555                 return (false);
 556         if (srcname[HALF_LEN] != '.')
 557                 return (false);
 558         for (i = 0; i < HALF_LEN; i++) {
 559                 if (srcname[i] < '0' || srcname[i] > '9')
 560                         return (false);
 561         }
 562         for (i = HALF_LEN + 1; i < 2 * HALF_LEN - 1; i++) {
 563                 if (srcname[i] < '0' || srcname[i] > '9')
 564                         break;
 565         }
 566         if (i < 2 * HALF_LEN - 1 &&
 567             strcmp(srcname + HALF_LEN + 1, "not_terminated") != 0 &&
 568             strcmp(srcname + HALF_LEN + 1, "crash_recovery") != 0) {
 569                 return (false);
 570         }
 571
 572         if (dstname == NULL)
 573                 return (true);
 574
 575         /* We tolarate if both names are identical. */
 576         if (strcmp(srcname, dstname) == 0)
 577                 return (true);
 578
 579         /* We can only rename not_terminated files. */
 580         if (strcmp(srcname + HALF_LEN + 1, "not_terminated") != 0)
 581                 return (false);
 582         if (strlen(dstname) != 2 * HALF_LEN + 1)
 583                 return (false);
 584         if (strncmp(srcname, dstname, HALF_LEN + 1) != 0)
 585                 return (false);
 586         for (i = HALF_LEN + 1; i < 2 * HALF_LEN - 1; i++) {
 587                 if (dstname[i] < '0' || dstname[i] > '9')
 588                         break;
 589         }
 590         if (i < 2 * HALF_LEN - 1 &&
 591             strcmp(dstname + HALF_LEN + 1, "crash_recovery") != 0) {
 592                 return (false);
 593         }
 594
 595         return (true);
 596 }
 597
 598 int
 599 trail_name_compare(const char *name0, const char *name1)
 600 {
 601         int ret;
 602
 603         ret = strcmp(name0, name1);
 604         if (ret == 0)
 605                 return (TRAIL_IDENTICAL);
 606         if (strncmp(name0, name1, HALF_LEN + 1) == 0)
 607                 return (TRAIL_RENAMED);
 608         return (ret < 0 ? TRAIL_OLDER : TRAIL_NEWER);
 609 }