src/journal/journald-native.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <stddef.h>
   4 #include <sys/epoll.h>
   5 #include <sys/mman.h>
   6 #include <sys/statvfs.h>
   7 #include <unistd.h>
   8
   9 #include "alloc-util.h"
  10 #include "fd-util.h"
  11 #include "fs-util.h"
  12 #include "io-util.h"
  13 #include "journal-importer.h"
  14 #include "journal-util.h"
  15 #include "journald-console.h"
  16 #include "journald-kmsg.h"
  17 #include "journald-native.h"
  18 #include "journald-server.h"
  19 #include "journald-syslog.h"
  20 #include "journald-wall.h"
  21 #include "memfd-util.h"
  22 #include "memory-util.h"
  23 #include "parse-util.h"
  24 #include "path-util.h"
  25 #include "process-util.h"
  26 #include "selinux-util.h"
  27 #include "socket-util.h"
  28 #include "string-util.h"
  29 #include "strv.h"
  30 #include "unaligned.h"
  31
  32 static bool allow_object_pid(const struct ucred *ucred) {
  33         return ucred && ucred->uid == 0;
  34 }
  35
  36 static void server_process_entry_meta(
  37                 const char *p, size_t l,
  38                 const struct ucred *ucred,
  39                 int *priority,
  40                 char **identifier,
  41                 char **message,
  42                 pid_t *object_pid) {
  43
  44         /* We need to determine the priority of this entry for the rate limiting logic */
  45
  46         if (l == 10 &&
  47             startswith(p, "PRIORITY=") &&
  48             p[9] >= '0' && p[9] <= '9')
  49                 *priority = (*priority & LOG_FACMASK) | (p[9] - '0');
  50
  51         else if (l == 17 &&
  52                  startswith(p, "SYSLOG_FACILITY=") &&
  53                  p[16] >= '0' && p[16] <= '9')
  54                 *priority = (*priority & LOG_PRIMASK) | ((p[16] - '0') << 3);
  55
  56         else if (l == 18 &&
  57                  startswith(p, "SYSLOG_FACILITY=") &&
  58                  p[16] >= '0' && p[16] <= '9' &&
  59                  p[17] >= '0' && p[17] <= '9')
  60                 *priority = (*priority & LOG_PRIMASK) | (((p[16] - '0')*10 + (p[17] - '0')) << 3);
  61
  62         else if (l >= 19 &&
  63                  startswith(p, "SYSLOG_IDENTIFIER=")) {
  64                 char *t;
  65
  66                 t = memdup_suffix0(p + 18, l - 18);
  67                 if (t) {
  68                         free(*identifier);
  69                         *identifier = t;
  70                 }
  71
  72         } else if (l >= 8 &&
  73                    startswith(p, "MESSAGE=")) {
  74                 char *t;
  75
  76                 t = memdup_suffix0(p + 8, l - 8);
  77                 if (t) {
  78                         free(*message);
  79                         *message = t;
  80                 }
  81
  82         } else if (l > STRLEN("OBJECT_PID=") &&
  83                    l < STRLEN("OBJECT_PID=")  + DECIMAL_STR_MAX(pid_t) &&
  84                    startswith(p, "OBJECT_PID=") &&
  85                    allow_object_pid(ucred)) {
  86                 char buf[DECIMAL_STR_MAX(pid_t)];
  87                 memcpy(buf, p + STRLEN("OBJECT_PID="),
  88                        l - STRLEN("OBJECT_PID="));
  89                 buf[l-STRLEN("OBJECT_PID=")] = '\0';
  90
  91                 (void) parse_pid(buf, object_pid);
  92         }
  93 }
  94
  95 static int server_process_entry(
  96                 Server *s,
  97                 const void *buffer, size_t *remaining,
  98                 ClientContext *context,
  99                 const struct ucred *ucred,
 100                 const struct timeval *tv,
 101                 const char *label, size_t label_len) {
 102
 103         /* Process a single entry from a native message. Returns 0 if nothing special happened and the message
 104          * processing should continue, and a negative or positive value otherwise.
 105          *
 106          * Note that *remaining is altered on both success and failure. */
 107
 108         size_t n = 0, j, tn = (size_t) -1, m = 0, entry_size = 0;
 109         char *identifier = NULL, *message = NULL;
 110         struct iovec *iovec = NULL;
 111         int priority = LOG_INFO;
 112         pid_t object_pid = 0;
 113         const char *p;
 114         int r = 1;
 115
 116         p = buffer;
 117
 118         while (*remaining > 0) {
 119                 const char *e, *q;
 120
 121                 e = memchr(p, '\n', *remaining);
 122
 123                 if (!e) {
 124                         /* Trailing noise, let's ignore it, and flush what we collected */
 125                         log_debug("Received message with trailing noise, ignoring.");
 126                         break; /* finish processing of the message */
 127                 }
 128
 129                 if (e == p) {
 130                         /* Entry separator */
 131                         *remaining -= 1;
 132                         break;
 133                 }
 134
 135                 if (IN_SET(*p, '.', '#')) {
 136                         /* Ignore control commands for now, and comments too. */
 137                         *remaining -= (e - p) + 1;
 138                         p = e + 1;
 139                         continue;
 140                 }
 141
 142                 /* A property follows */
 143                 if (n > ENTRY_FIELD_COUNT_MAX) {
 144                         log_debug("Received an entry that has more than " STRINGIFY(ENTRY_FIELD_COUNT_MAX) " fields, ignoring entry.");
 145                         goto finish;
 146                 }
 147
 148                 /* n existing properties, 1 new, +1 for _TRANSPORT */
 149                 if (!GREEDY_REALLOC(iovec, m,
 150                                     n + 2 +
 151                                     N_IOVEC_META_FIELDS + N_IOVEC_OBJECT_FIELDS +
 152                                     client_context_extra_fields_n_iovec(context))) {
 153                         r = log_oom();
 154                         goto finish;
 155                 }
 156
 157                 q = memchr(p, '=', e - p);
 158                 if (q) {
 159                         if (journal_field_valid(p, q - p, false)) {
 160                                 size_t l;
 161
 162                                 l = e - p;
 163                                 if (l > DATA_SIZE_MAX) {
 164                                         log_debug("Received text block of %zu bytes is too large, ignoring entry.", l);
 165                                         goto finish;
 166                                 }
 167
 168                                 if (entry_size + l + n + 1 > ENTRY_SIZE_MAX) { /* data + separators + trailer */
 169                                         log_debug("Entry is too big (%zu bytes after processing %zu entries), ignoring entry.",
 170                                                   entry_size + l, n + 1);
 171                                         goto finish;
 172                                 }
 173
 174                                 /* If the field name starts with an underscore, skip the variable, since that indicates
 175                                  * a trusted field */
 176                                 iovec[n++] = IOVEC_MAKE((char*) p, l);
 177                                 entry_size += l;
 178
 179                                 server_process_entry_meta(p, l, ucred,
 180                                                           &priority,
 181                                                           &identifier,
 182                                                           &message,
 183                                                           &object_pid);
 184                         }
 185
 186                         *remaining -= (e - p) + 1;
 187                         p = e + 1;
 188                         continue;
 189                 } else {
 190                         uint64_t l, total;
 191                         char *k;
 192
 193                         if (*remaining < e - p + 1 + sizeof(uint64_t) + 1) {
 194                                 log_debug("Failed to parse message, ignoring.");
 195                                 break;
 196                         }
 197
 198                         l = unaligned_read_le64(e + 1);
 199                         if (l > DATA_SIZE_MAX) {
 200                                 log_debug("Received binary data block of %"PRIu64" bytes is too large, ignoring entry.", l);
 201                                 goto finish;
 202                         }
 203
 204                         total = (e - p) + 1 + l;
 205                         if (entry_size + total + n + 1 > ENTRY_SIZE_MAX) { /* data + separators + trailer */
 206                                 log_debug("Entry is too big (%"PRIu64"bytes after processing %zu fields), ignoring.",
 207                                           entry_size + total, n + 1);
 208                                 goto finish;
 209                         }
 210
 211                         if ((uint64_t) *remaining < e - p + 1 + sizeof(uint64_t) + l + 1 ||
 212                             e[1+sizeof(uint64_t)+l] != '\n') {
 213                                 log_debug("Failed to parse message, ignoring.");
 214                                 break;
 215                         }
 216
 217                         k = malloc(total);
 218                         if (!k) {
 219                                 log_oom();
 220                                 break;
 221                         }
 222
 223                         memcpy(k, p, e - p);
 224                         k[e - p] = '=';
 225                         memcpy(k + (e - p) + 1, e + 1 + sizeof(uint64_t), l);
 226
 227                         if (journal_field_valid(p, e - p, false)) {
 228                                 iovec[n] = IOVEC_MAKE(k, (e - p) + 1 + l);
 229                                 entry_size += iovec[n].iov_len;
 230                                 n++;
 231
 232                                 server_process_entry_meta(k, (e - p) + 1 + l, ucred,
 233                                                           &priority,
 234                                                           &identifier,
 235                                                           &message,
 236                                                           &object_pid);
 237                         } else
 238                                 free(k);
 239
 240                         *remaining -= (e - p) + 1 + sizeof(uint64_t) + l + 1;
 241                         p = e + 1 + sizeof(uint64_t) + l + 1;
 242                 }
 243         }
 244
 245         if (n <= 0)
 246                 goto finish;
 247
 248         tn = n++;
 249         iovec[tn] = IOVEC_MAKE_STRING("_TRANSPORT=journal");
 250         entry_size += STRLEN("_TRANSPORT=journal");
 251
 252         if (entry_size + n + 1 > ENTRY_SIZE_MAX) { /* data + separators + trailer */
 253                 log_debug("Entry is too big with %zu properties and %zu bytes, ignoring.", n, entry_size);
 254                 goto finish;
 255         }
 256
 257         r = 0; /* Success, we read the message. */
 258
 259         if (!client_context_test_priority(context, priority))
 260                 goto finish;
 261
 262         if (message) {
 263                 if (s->forward_to_syslog)
 264                         server_forward_syslog(s, syslog_fixup_facility(priority), identifier, message, ucred, tv);
 265
 266                 if (s->forward_to_kmsg)
 267                         server_forward_kmsg(s, priority, identifier, message, ucred);
 268
 269                 if (s->forward_to_console)
 270                         server_forward_console(s, priority, identifier, message, ucred);
 271
 272                 if (s->forward_to_wall)
 273                         server_forward_wall(s, priority, identifier, message, ucred);
 274         }
 275
 276         server_dispatch_message(s, iovec, n, m, context, tv, priority, object_pid);
 277
 278 finish:
 279         for (j = 0; j < n; j++)  {
 280                 if (j == tn)
 281                         continue;
 282
 283                 if (iovec[j].iov_base < buffer ||
 284                     (const char*) iovec[j].iov_base >= p + *remaining)
 285                         free(iovec[j].iov_base);
 286         }
 287
 288         free(iovec);
 289         free(identifier);
 290         free(message);
 291
 292         return r;
 293 }
 294
 295 void server_process_native_message(
 296                 Server *s,
 297                 const char *buffer, size_t buffer_size,
 298                 const struct ucred *ucred,
 299                 const struct timeval *tv,
 300                 const char *label, size_t label_len) {
 301
 302         size_t remaining = buffer_size;
 303         ClientContext *context = NULL;
 304         int r;
 305
 306         assert(s);
 307         assert(buffer || buffer_size == 0);
 308
 309         if (ucred && pid_is_valid(ucred->pid)) {
 310                 r = client_context_get(s, ucred->pid, ucred, label, label_len, NULL, &context);
 311                 if (r < 0)
 312                         log_warning_errno(r, "Failed to retrieve credentials for PID " PID_FMT ", ignoring: %m", ucred->pid);
 313         }
 314
 315         do {
 316                 r = server_process_entry(s,
 317                                          (const uint8_t*) buffer + (buffer_size - remaining), &remaining,
 318                                          context, ucred, tv, label, label_len);
 319         } while (r == 0);
 320 }
 321
 322 void server_process_native_file(
 323                 Server *s,
 324                 int fd,
 325                 const struct ucred *ucred,
 326                 const struct timeval *tv,
 327                 const char *label, size_t label_len) {
 328
 329         struct stat st;
 330         bool sealed;
 331         int r;
 332
 333         /* Data is in the passed fd, probably it didn't fit in a datagram. */
 334
 335         assert(s);
 336         assert(fd >= 0);
 337
 338         /* If it's a memfd, check if it is sealed. If so, we can just
 339          * mmap it and use it, and do not need to copy the data out. */
 340         sealed = memfd_get_sealed(fd) > 0;
 341
 342         if (!sealed && (!ucred || ucred->uid != 0)) {
 343                 _cleanup_free_ char *k = NULL;
 344                 const char *e;
 345
 346                 /* If this is not a sealed memfd, and the peer is unknown or
 347                  * unprivileged, then verify the path. */
 348
 349                 r = fd_get_path(fd, &k);
 350                 if (r < 0) {
 351                         log_error_errno(r, "readlink(/proc/self/fd/%i) failed: %m", fd);
 352                         return;
 353                 }
 354
 355                 e = PATH_STARTSWITH_SET(k, "/dev/shm/", "/tmp/", "/var/tmp/");
 356                 if (!e) {
 357                         log_error("Received file outside of allowed directories. Refusing.");
 358                         return;
 359                 }
 360
 361                 if (!filename_is_valid(e)) {
 362                         log_error("Received file in subdirectory of allowed directories. Refusing.");
 363                         return;
 364                 }
 365         }
 366
 367         if (fstat(fd, &st) < 0) {
 368                 log_error_errno(errno, "Failed to stat passed file, ignoring: %m");
 369                 return;
 370         }
 371
 372         if (!S_ISREG(st.st_mode)) {
 373                 log_error("File passed is not regular. Ignoring.");
 374                 return;
 375         }
 376
 377         if (st.st_size <= 0)
 378                 return;
 379
 380         /* When !sealed, set a lower memory limit. We have to read the file,
 381          * effectively doubling memory use. */
 382         if (st.st_size > ENTRY_SIZE_MAX / (sealed ? 1 : 2)) {
 383                 log_error("File passed too large (%"PRIu64" bytes). Ignoring.", (uint64_t) st.st_size);
 384                 return;
 385         }
 386
 387         if (sealed) {
 388                 void *p;
 389                 size_t ps;
 390
 391                 /* The file is sealed, we can just map it and use it. */
 392
 393                 ps = PAGE_ALIGN(st.st_size);
 394                 p = mmap(NULL, ps, PROT_READ, MAP_PRIVATE, fd, 0);
 395                 if (p == MAP_FAILED) {
 396                         log_error_errno(errno, "Failed to map memfd, ignoring: %m");
 397                         return;
 398                 }
 399
 400                 server_process_native_message(s, p, st.st_size, ucred, tv, label, label_len);
 401                 assert_se(munmap(p, ps) >= 0);
 402         } else {
 403                 _cleanup_free_ void *p = NULL;
 404                 struct statvfs vfs;
 405                 ssize_t n;
 406
 407                 if (fstatvfs(fd, &vfs) < 0) {
 408                         log_error_errno(errno, "Failed to stat file system of passed file, not processing it: %m");
 409                         return;
 410                 }
 411
 412                 /* Refuse operating on file systems that have
 413                  * mandatory locking enabled, see:
 414                  *
 415                  * https://github.com/systemd/systemd/issues/1822
 416                  */
 417                 if (vfs.f_flag & ST_MANDLOCK) {
 418                         log_error("Received file descriptor from file system with mandatory locking enabled, not processing it.");
 419                         return;
 420                 }
 421
 422                 /* Make the fd non-blocking. On regular files this has
 423                  * the effect of bypassing mandatory locking. Of
 424                  * course, this should normally not be necessary given
 425                  * the check above, but let's better be safe than
 426                  * sorry, after all NFS is pretty confusing regarding
 427                  * file system flags, and we better don't trust it,
 428                  * and so is SMB. */
 429                 r = fd_nonblock(fd, true);
 430                 if (r < 0) {
 431                         log_error_errno(r, "Failed to make fd non-blocking, not processing it: %m");
 432                         return;
 433                 }
 434
 435                 /* The file is not sealed, we can't map the file here, since
 436                  * clients might then truncate it and trigger a SIGBUS for
 437                  * us. So let's stupidly read it. */
 438
 439                 p = malloc(st.st_size);
 440                 if (!p) {
 441                         log_oom();
 442                         return;
 443                 }
 444
 445                 n = pread(fd, p, st.st_size, 0);
 446                 if (n < 0)
 447                         log_error_errno(errno, "Failed to read file, ignoring: %m");
 448                 else if (n > 0)
 449                         server_process_native_message(s, p, n, ucred, tv, label, label_len);
 450         }
 451 }
 452
 453 int server_open_native_socket(Server *s, const char *native_socket) {
 454         int r;
 455
 456         assert(s);
 457         assert(native_socket);
 458
 459         if (s->native_fd < 0) {
 460                 union sockaddr_union sa;
 461                 size_t sa_len;
 462
 463                 r = sockaddr_un_set_path(&sa.un, native_socket);
 464                 if (r < 0)
 465                         return log_error_errno(r, "Unable to use namespace path %s for AF_UNIX socket: %m", native_socket);
 466                 sa_len = r;
 467
 468                 s->native_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 469                 if (s->native_fd < 0)
 470                         return log_error_errno(errno, "socket() failed: %m");
 471
 472                 (void) sockaddr_un_unlink(&sa.un);
 473
 474                 r = bind(s->native_fd, &sa.sa, sa_len);
 475                 if (r < 0)
 476                         return log_error_errno(errno, "bind(%s) failed: %m", sa.un.sun_path);
 477
 478                 (void) chmod(sa.un.sun_path, 0666);
 479         } else
 480                 (void) fd_nonblock(s->native_fd, true);
 481
 482         r = setsockopt_int(s->native_fd, SOL_SOCKET, SO_PASSCRED, true);
 483         if (r < 0)
 484                 return log_error_errno(r, "SO_PASSCRED failed: %m");
 485
 486         if (mac_selinux_use()) {
 487                 r = setsockopt_int(s->native_fd, SOL_SOCKET, SO_PASSSEC, true);
 488                 if (r < 0)
 489                         log_warning_errno(r, "SO_PASSSEC failed: %m");
 490         }
 491
 492         r = setsockopt_int(s->native_fd, SOL_SOCKET, SO_TIMESTAMP, true);
 493         if (r < 0)
 494                 return log_error_errno(r, "SO_TIMESTAMP failed: %m");
 495
 496         r = sd_event_add_io(s->event, &s->native_event_source, s->native_fd, EPOLLIN, server_process_datagram, s);
 497         if (r < 0)
 498                 return log_error_errno(r, "Failed to add native server fd to event loop: %m");
 499
 500         r = sd_event_source_set_priority(s->native_event_source, SD_EVENT_PRIORITY_NORMAL+5);
 501         if (r < 0)
 502                 return log_error_errno(r, "Failed to adjust native event source priority: %m");
 503
 504         return 0;
 505 }