src/journal/journald-native.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2011 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <stddef.h>
  21 #include <sys/epoll.h>
  22 #include <sys/mman.h>
  23 #include <sys/statvfs.h>
  24 #include <unistd.h>
  25
  26 #include "alloc-util.h"
  27 #include "fd-util.h"
  28 #include "fs-util.h"
  29 #include "io-util.h"
  30 #include "journal-importer.h"
  31 #include "journal-util.h"
  32 #include "journald-console.h"
  33 #include "journald-kmsg.h"
  34 #include "journald-native.h"
  35 #include "journald-server.h"
  36 #include "journald-syslog.h"
  37 #include "journald-wall.h"
  38 #include "memfd-util.h"
  39 #include "parse-util.h"
  40 #include "path-util.h"
  41 #include "process-util.h"
  42 #include "selinux-util.h"
  43 #include "socket-util.h"
  44 #include "string-util.h"
  45 #include "unaligned.h"
  46
  47 static bool allow_object_pid(const struct ucred *ucred) {
  48         return ucred && ucred->uid == 0;
  49 }
  50
  51 static void server_process_entry_meta(
  52                 const char *p, size_t l,
  53                 const struct ucred *ucred,
  54                 int *priority,
  55                 char **identifier,
  56                 char **message,
  57                 pid_t *object_pid) {
  58
  59         /* We need to determine the priority of this entry for the rate limiting logic */
  60
  61         if (l == 10 &&
  62             startswith(p, "PRIORITY=") &&
  63             p[9] >= '0' && p[9] <= '9')
  64                 *priority = (*priority & LOG_FACMASK) | (p[9] - '0');
  65
  66         else if (l == 17 &&
  67                  startswith(p, "SYSLOG_FACILITY=") &&
  68                  p[16] >= '0' && p[16] <= '9')
  69                 *priority = (*priority & LOG_PRIMASK) | ((p[16] - '0') << 3);
  70
  71         else if (l == 18 &&
  72                  startswith(p, "SYSLOG_FACILITY=") &&
  73                  p[16] >= '0' && p[16] <= '9' &&
  74                  p[17] >= '0' && p[17] <= '9')
  75                 *priority = (*priority & LOG_PRIMASK) | (((p[16] - '0')*10 + (p[17] - '0')) << 3);
  76
  77         else if (l >= 19 &&
  78                  startswith(p, "SYSLOG_IDENTIFIER=")) {
  79                 char *t;
  80
  81                 t = strndup(p + 18, l - 18);
  82                 if (t) {
  83                         free(*identifier);
  84                         *identifier = t;
  85                 }
  86
  87         } else if (l >= 8 &&
  88                    startswith(p, "MESSAGE=")) {
  89                 char *t;
  90
  91                 t = strndup(p + 8, l - 8);
  92                 if (t) {
  93                         free(*message);
  94                         *message = t;
  95                 }
  96
  97         } else if (l > strlen("OBJECT_PID=") &&
  98                    l < strlen("OBJECT_PID=")  + DECIMAL_STR_MAX(pid_t) &&
  99                    startswith(p, "OBJECT_PID=") &&
 100                    allow_object_pid(ucred)) {
 101                 char buf[DECIMAL_STR_MAX(pid_t)];
 102                 memcpy(buf, p + strlen("OBJECT_PID="), l - strlen("OBJECT_PID="));
 103                 buf[l-strlen("OBJECT_PID=")] = '\0';
 104
 105                 (void) parse_pid(buf, object_pid);
 106         }
 107 }
 108
 109 static int server_process_entry(
 110                 Server *s,
 111                 const void *buffer, size_t *remaining,
 112                 ClientContext *context,
 113                 const struct ucred *ucred,
 114                 const struct timeval *tv,
 115                 const char *label, size_t label_len) {
 116
 117         /* Process a single entry from a native message. Returns 0 if nothing special happened and the message
 118          * processing should continue, and a negative or positive value otherwise.
 119          *
 120          * Note that *remaining is altered on both success and failure. */
 121
 122         size_t n = 0, j, tn = (size_t) -1, m = 0, entry_size = 0;
 123         char *identifier = NULL, *message = NULL;
 124         struct iovec *iovec = NULL;
 125         int priority = LOG_INFO;
 126         pid_t object_pid = 0;
 127         const char *p;
 128         int r = 0;
 129
 130         p = buffer;
 131
 132         while (*remaining > 0) {
 133                 const char *e, *q;
 134
 135                 e = memchr(p, '\n', *remaining);
 136
 137                 if (!e) {
 138                         /* Trailing noise, let's ignore it, and flush what we collected */
 139                         log_debug("Received message with trailing noise, ignoring.");
 140                         r = 1; /* finish processing of the message */
 141                         break;
 142                 }
 143
 144                 if (e == p) {
 145                         /* Entry separator */
 146                         *remaining -= 1;
 147                         break;
 148                 }
 149
 150                 if (IN_SET(*p, '.', '#')) {
 151                         /* Ignore control commands for now, and
 152                          * comments too. */
 153                         *remaining -= (e - p) + 1;
 154                         p = e + 1;
 155                         continue;
 156                 }
 157
 158                 /* A property follows */
 159
 160                 /* n existing properties, 1 new, +1 for _TRANSPORT */
 161                 if (!GREEDY_REALLOC(iovec, m,
 162                                     n + 2 +
 163                                     N_IOVEC_META_FIELDS + N_IOVEC_OBJECT_FIELDS +
 164                                     client_context_extra_fields_n_iovec(context))) {
 165                         r = log_oom();
 166                         break;
 167                 }
 168
 169                 q = memchr(p, '=', e - p);
 170                 if (q) {
 171                         if (journal_field_valid(p, q - p, false)) {
 172                                 size_t l;
 173
 174                                 l = e - p;
 175
 176                                 /* If the field name starts with an underscore, skip the variable, since that indicates
 177                                  * a trusted field */
 178                                 iovec[n++] = IOVEC_MAKE((char*) p, l);
 179                                 entry_size += l;
 180
 181                                 server_process_entry_meta(p, l, ucred,
 182                                                           &priority,
 183                                                           &identifier,
 184                                                           &message,
 185                                                           &object_pid);
 186                         }
 187
 188                         *remaining -= (e - p) + 1;
 189                         p = e + 1;
 190                         continue;
 191                 } else {
 192                         uint64_t l;
 193                         char *k;
 194
 195                         if (*remaining < e - p + 1 + sizeof(uint64_t) + 1) {
 196                                 log_debug("Failed to parse message, ignoring.");
 197                                 break;
 198                         }
 199
 200                         l = unaligned_read_le64(e + 1);
 201
 202                         if (l > DATA_SIZE_MAX) {
 203                                 log_debug("Received binary data block of %"PRIu64" bytes is too large, ignoring.", l);
 204                                 break;
 205                         }
 206
 207                         if ((uint64_t) *remaining < e - p + 1 + sizeof(uint64_t) + l + 1 ||
 208                             e[1+sizeof(uint64_t)+l] != '\n') {
 209                                 log_debug("Failed to parse message, ignoring.");
 210                                 break;
 211                         }
 212
 213                         k = malloc((e - p) + 1 + l);
 214                         if (!k) {
 215                                 log_oom();
 216                                 break;
 217                         }
 218
 219                         memcpy(k, p, e - p);
 220                         k[e - p] = '=';
 221                         memcpy(k + (e - p) + 1, e + 1 + sizeof(uint64_t), l);
 222
 223                         if (journal_field_valid(p, e - p, false)) {
 224                                 iovec[n].iov_base = k;
 225                                 iovec[n].iov_len = (e - p) + 1 + l;
 226                                 entry_size += iovec[n].iov_len;
 227                                 n++;
 228
 229                                 server_process_entry_meta(k, (e - p) + 1 + l, ucred,
 230                                                           &priority,
 231                                                           &identifier,
 232                                                           &message,
 233                                                           &object_pid);
 234                         } else
 235                                 free(k);
 236
 237                         *remaining -= (e - p) + 1 + sizeof(uint64_t) + l + 1;
 238                         p = e + 1 + sizeof(uint64_t) + l + 1;
 239                 }
 240         }
 241
 242         if (n <= 0) {
 243                 r = 1;
 244                 goto finish;
 245         }
 246
 247         if (!client_context_test_priority(context, priority)) {
 248                 r = 0;
 249                 goto finish;
 250         }
 251
 252         tn = n++;
 253         iovec[tn] = IOVEC_MAKE_STRING("_TRANSPORT=journal");
 254         entry_size += strlen("_TRANSPORT=journal");
 255
 256         if (entry_size + n + 1 > ENTRY_SIZE_MAX) { /* data + separators + trailer */
 257                 log_debug("Entry is too big with %zu properties and %zu bytes, ignoring.", n, entry_size);
 258                 goto finish;
 259         }
 260
 261         if (message) {
 262                 if (s->forward_to_syslog)
 263                         server_forward_syslog(s, syslog_fixup_facility(priority), identifier, message, ucred, tv);
 264
 265                 if (s->forward_to_kmsg)
 266                         server_forward_kmsg(s, priority, identifier, message, ucred);
 267
 268                 if (s->forward_to_console)
 269                         server_forward_console(s, priority, identifier, message, ucred);
 270
 271                 if (s->forward_to_wall)
 272                         server_forward_wall(s, priority, identifier, message, ucred);
 273         }
 274
 275         server_dispatch_message(s, iovec, n, m, context, tv, priority, object_pid);
 276
 277 finish:
 278         for (j = 0; j < n; j++)  {
 279                 if (j == tn)
 280                         continue;
 281
 282                 if (iovec[j].iov_base < buffer ||
 283                     (const char*) iovec[j].iov_base >= p + *remaining)
 284                         free(iovec[j].iov_base);
 285         }
 286
 287         free(iovec);
 288         free(identifier);
 289         free(message);
 290
 291         return r;
 292 }
 293
 294 void server_process_native_message(
 295                 Server *s,
 296                 const void *buffer, size_t buffer_size,
 297                 const struct ucred *ucred,
 298                 const struct timeval *tv,
 299                 const char *label, size_t label_len) {
 300
 301         size_t remaining = buffer_size;
 302         ClientContext *context = NULL;
 303         int r;
 304
 305         assert(s);
 306         assert(buffer || buffer_size == 0);
 307
 308         if (ucred && pid_is_valid(ucred->pid)) {
 309                 r = client_context_get(s, ucred->pid, ucred, label, label_len, NULL, &context);
 310                 if (r < 0)
 311                         log_warning_errno(r, "Failed to retrieve credentials for PID " PID_FMT ", ignoring: %m", ucred->pid);
 312         }
 313
 314         do {
 315                 r = server_process_entry(s,
 316                                          (const uint8_t*) buffer + (buffer_size - remaining), &remaining,
 317                                          context, ucred, tv, label, label_len);
 318         } while (r == 0);
 319 }
 320
 321 void server_process_native_file(
 322                 Server *s,
 323                 int fd,
 324                 const struct ucred *ucred,
 325                 const struct timeval *tv,
 326                 const char *label, size_t label_len) {
 327
 328         struct stat st;
 329         bool sealed;
 330         int r;
 331
 332         /* Data is in the passed fd, since it didn't fit in a
 333          * 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          * use map it and use it, and do not need to copy the data
 340          * out. */
 341         sealed = memfd_get_sealed(fd) > 0;
 342
 343         if (!sealed && (!ucred || ucred->uid != 0)) {
 344                 _cleanup_free_ char *sl = NULL, *k = NULL;
 345                 const char *e;
 346
 347                 /* If this is not a sealed memfd, and the peer is unknown or
 348                  * unprivileged, then verify the path. */
 349
 350                 if (asprintf(&sl, "/proc/self/fd/%i", fd) < 0) {
 351                         log_oom();
 352                         return;
 353                 }
 354
 355                 r = readlink_malloc(sl, &k);
 356                 if (r < 0) {
 357                         log_error_errno(r, "readlink(%s) failed: %m", sl);
 358                         return;
 359                 }
 360
 361                 e = path_startswith(k, "/dev/shm/");
 362                 if (!e)
 363                         e = path_startswith(k, "/tmp/");
 364                 if (!e)
 365                         e = path_startswith(k, "/var/tmp/");
 366                 if (!e) {
 367                         log_error("Received file outside of allowed directories. Refusing.");
 368                         return;
 369                 }
 370
 371                 if (!filename_is_valid(e)) {
 372                         log_error("Received file in subdirectory of allowed directories. Refusing.");
 373                         return;
 374                 }
 375         }
 376
 377         if (fstat(fd, &st) < 0) {
 378                 log_error_errno(errno, "Failed to stat passed file, ignoring: %m");
 379                 return;
 380         }
 381
 382         if (!S_ISREG(st.st_mode)) {
 383                 log_error("File passed is not regular. Ignoring.");
 384                 return;
 385         }
 386
 387         if (st.st_size <= 0)
 388                 return;
 389
 390         if (st.st_size > ENTRY_SIZE_MAX) {
 391                 log_error("File passed too large. Ignoring.");
 392                 return;
 393         }
 394
 395         if (sealed) {
 396                 void *p;
 397                 size_t ps;
 398
 399                 /* The file is sealed, we can just map it and use it. */
 400
 401                 ps = PAGE_ALIGN(st.st_size);
 402                 p = mmap(NULL, ps, PROT_READ, MAP_PRIVATE, fd, 0);
 403                 if (p == MAP_FAILED) {
 404                         log_error_errno(errno, "Failed to map memfd, ignoring: %m");
 405                         return;
 406                 }
 407
 408                 server_process_native_message(s, p, st.st_size, ucred, tv, label, label_len);
 409                 assert_se(munmap(p, ps) >= 0);
 410         } else {
 411                 _cleanup_free_ void *p = NULL;
 412                 struct statvfs vfs;
 413                 ssize_t n;
 414
 415                 if (fstatvfs(fd, &vfs) < 0) {
 416                         log_error_errno(errno, "Failed to stat file system of passed file, ignoring: %m");
 417                         return;
 418                 }
 419
 420                 /* Refuse operating on file systems that have
 421                  * mandatory locking enabled, see:
 422                  *
 423                  * https://github.com/systemd/systemd/issues/1822
 424                  */
 425                 if (vfs.f_flag & ST_MANDLOCK) {
 426                         log_error("Received file descriptor from file system with mandatory locking enable, refusing.");
 427                         return;
 428                 }
 429
 430                 /* Make the fd non-blocking. On regular files this has
 431                  * the effect of bypassing mandatory locking. Of
 432                  * course, this should normally not be necessary given
 433                  * the check above, but let's better be safe than
 434                  * sorry, after all NFS is pretty confusing regarding
 435                  * file system flags, and we better don't trust it,
 436                  * and so is SMB. */
 437                 r = fd_nonblock(fd, true);
 438                 if (r < 0) {
 439                         log_error_errno(r, "Failed to make fd non-blocking, ignoring: %m");
 440                         return;
 441                 }
 442
 443                 /* The file is not sealed, we can't map the file here, since
 444                  * clients might then truncate it and trigger a SIGBUS for
 445                  * us. So let's stupidly read it */
 446
 447                 p = malloc(st.st_size);
 448                 if (!p) {
 449                         log_oom();
 450                         return;
 451                 }
 452
 453                 n = pread(fd, p, st.st_size, 0);
 454                 if (n < 0)
 455                         log_error_errno(errno, "Failed to read file, ignoring: %m");
 456                 else if (n > 0)
 457                         server_process_native_message(s, p, n, ucred, tv, label, label_len);
 458         }
 459 }
 460
 461 int server_open_native_socket(Server*s) {
 462
 463         static const union sockaddr_union sa = {
 464                 .un.sun_family = AF_UNIX,
 465                 .un.sun_path = "/run/systemd/journal/socket",
 466         };
 467         static const int one = 1;
 468         int r;
 469
 470         assert(s);
 471
 472         if (s->native_fd < 0) {
 473                 s->native_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 474                 if (s->native_fd < 0)
 475                         return log_error_errno(errno, "socket() failed: %m");
 476
 477                 (void) unlink(sa.un.sun_path);
 478
 479                 r = bind(s->native_fd, &sa.sa, SOCKADDR_UN_LEN(sa.un));
 480                 if (r < 0)
 481                         return log_error_errno(errno, "bind(%s) failed: %m", sa.un.sun_path);
 482
 483                 (void) chmod(sa.un.sun_path, 0666);
 484         } else
 485                 fd_nonblock(s->native_fd, 1);
 486
 487         r = setsockopt(s->native_fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one));
 488         if (r < 0)
 489                 return log_error_errno(errno, "SO_PASSCRED failed: %m");
 490
 491 #if HAVE_SELINUX
 492         if (mac_selinux_use()) {
 493                 r = setsockopt(s->native_fd, SOL_SOCKET, SO_PASSSEC, &one, sizeof(one));
 494                 if (r < 0)
 495                         log_warning_errno(errno, "SO_PASSSEC failed: %m");
 496         }
 497 #endif
 498
 499         r = setsockopt(s->native_fd, SOL_SOCKET, SO_TIMESTAMP, &one, sizeof(one));
 500         if (r < 0)
 501                 return log_error_errno(errno, "SO_TIMESTAMP failed: %m");
 502
 503         r = sd_event_add_io(s->event, &s->native_event_source, s->native_fd, EPOLLIN, server_process_datagram, s);
 504         if (r < 0)
 505                 return log_error_errno(r, "Failed to add native server fd to event loop: %m");
 506
 507         r = sd_event_source_set_priority(s->native_event_source, SD_EVENT_PRIORITY_NORMAL+5);
 508         if (r < 0)
 509                 return log_error_errno(r, "Failed to adjust native event source priority: %m");
 510
 511         return 0;
 512 }