src/journal/journald-syslog.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <stddef.h>
   4 #include <sys/epoll.h>
   5 #include <unistd.h>
   6
   7 #include "sd-messages.h"
   8
   9 #include "alloc-util.h"
  10 #include "fd-util.h"
  11 #include "format-util.h"
  12 #include "io-util.h"
  13 #include "journald-console.h"
  14 #include "journald-kmsg.h"
  15 #include "journald-server.h"
  16 #include "journald-syslog.h"
  17 #include "journald-wall.h"
  18 #include "process-util.h"
  19 #include "selinux-util.h"
  20 #include "socket-util.h"
  21 #include "stdio-util.h"
  22 #include "string-util.h"
  23 #include "syslog-util.h"
  24
  25 /* Warn once every 30s if we missed syslog message */
  26 #define WARN_FORWARD_SYSLOG_MISSED_USEC (30 * USEC_PER_SEC)
  27
  28 static void forward_syslog_iovec(Server *s, const struct iovec *iovec, unsigned n_iovec, const struct ucred *ucred, const struct timeval *tv) {
  29
  30         static const union sockaddr_union sa = {
  31                 .un.sun_family = AF_UNIX,
  32                 .un.sun_path = "/run/systemd/journal/syslog",
  33         };
  34         struct msghdr msghdr = {
  35                 .msg_iov = (struct iovec *) iovec,
  36                 .msg_iovlen = n_iovec,
  37                 .msg_name = (struct sockaddr*) &sa.sa,
  38                 .msg_namelen = SOCKADDR_UN_LEN(sa.un),
  39         };
  40         struct cmsghdr *cmsg;
  41         union {
  42                 struct cmsghdr cmsghdr;
  43                 uint8_t buf[CMSG_SPACE(sizeof(struct ucred))];
  44         } control;
  45
  46         assert(s);
  47         assert(iovec);
  48         assert(n_iovec > 0);
  49
  50         if (ucred) {
  51                 zero(control);
  52                 msghdr.msg_control = &control;
  53                 msghdr.msg_controllen = sizeof(control);
  54
  55                 cmsg = CMSG_FIRSTHDR(&msghdr);
  56                 cmsg->cmsg_level = SOL_SOCKET;
  57                 cmsg->cmsg_type = SCM_CREDENTIALS;
  58                 cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
  59                 memcpy(CMSG_DATA(cmsg), ucred, sizeof(struct ucred));
  60                 msghdr.msg_controllen = cmsg->cmsg_len;
  61         }
  62
  63         /* Forward the syslog message we received via /dev/log to
  64          * /run/systemd/syslog. Unfortunately we currently can't set
  65          * the SO_TIMESTAMP auxiliary data, and hence we don't. */
  66
  67         if (sendmsg(s->syslog_fd, &msghdr, MSG_NOSIGNAL) >= 0)
  68                 return;
  69
  70         /* The socket is full? I guess the syslog implementation is
  71          * too slow, and we shouldn't wait for that... */
  72         if (errno == EAGAIN) {
  73                 s->n_forward_syslog_missed++;
  74                 return;
  75         }
  76
  77         if (ucred && IN_SET(errno, ESRCH, EPERM)) {
  78                 struct ucred u;
  79
  80                 /* Hmm, presumably the sender process vanished
  81                  * by now, or we don't have CAP_SYS_AMDIN, so
  82                  * let's fix it as good as we can, and retry */
  83
  84                 u = *ucred;
  85                 u.pid = getpid_cached();
  86                 memcpy(CMSG_DATA(cmsg), &u, sizeof(struct ucred));
  87
  88                 if (sendmsg(s->syslog_fd, &msghdr, MSG_NOSIGNAL) >= 0)
  89                         return;
  90
  91                 if (errno == EAGAIN) {
  92                         s->n_forward_syslog_missed++;
  93                         return;
  94                 }
  95         }
  96
  97         if (errno != ENOENT)
  98                 log_debug_errno(errno, "Failed to forward syslog message: %m");
  99 }
 100
 101 static void forward_syslog_raw(Server *s, int priority, const char *buffer, size_t buffer_len, const struct ucred *ucred, const struct timeval *tv) {
 102         struct iovec iovec;
 103
 104         assert(s);
 105         assert(buffer);
 106
 107         if (LOG_PRI(priority) > s->max_level_syslog)
 108                 return;
 109
 110         iovec = IOVEC_MAKE((char *) buffer, buffer_len);
 111         forward_syslog_iovec(s, &iovec, 1, ucred, tv);
 112 }
 113
 114 void server_forward_syslog(Server *s, int priority, const char *identifier, const char *message, const struct ucred *ucred, const struct timeval *tv) {
 115         struct iovec iovec[5];
 116         char header_priority[DECIMAL_STR_MAX(priority) + 3], header_time[64],
 117              header_pid[STRLEN("[]: ") + DECIMAL_STR_MAX(pid_t) + 1];
 118         int n = 0;
 119         time_t t;
 120         struct tm tm;
 121         _cleanup_free_ char *ident_buf = NULL;
 122
 123         assert(s);
 124         assert(priority >= 0);
 125         assert(priority <= 999);
 126         assert(message);
 127
 128         if (LOG_PRI(priority) > s->max_level_syslog)
 129                 return;
 130
 131         /* First: priority field */
 132         xsprintf(header_priority, "<%i>", priority);
 133         iovec[n++] = IOVEC_MAKE_STRING(header_priority);
 134
 135         /* Second: timestamp */
 136         t = tv ? tv->tv_sec : ((time_t) (now(CLOCK_REALTIME) / USEC_PER_SEC));
 137         if (!localtime_r(&t, &tm))
 138                 return;
 139         if (strftime(header_time, sizeof(header_time), "%h %e %T ", &tm) <= 0)
 140                 return;
 141         iovec[n++] = IOVEC_MAKE_STRING(header_time);
 142
 143         /* Third: identifier and PID */
 144         if (ucred) {
 145                 if (!identifier) {
 146                         get_process_comm(ucred->pid, &ident_buf);
 147                         identifier = ident_buf;
 148                 }
 149
 150                 xsprintf(header_pid, "["PID_FMT"]: ", ucred->pid);
 151
 152                 if (identifier)
 153                         iovec[n++] = IOVEC_MAKE_STRING(identifier);
 154
 155                 iovec[n++] = IOVEC_MAKE_STRING(header_pid);
 156         } else if (identifier) {
 157                 iovec[n++] = IOVEC_MAKE_STRING(identifier);
 158                 iovec[n++] = IOVEC_MAKE_STRING(": ");
 159         }
 160
 161         /* Fourth: message */
 162         iovec[n++] = IOVEC_MAKE_STRING(message);
 163
 164         forward_syslog_iovec(s, iovec, n, ucred, tv);
 165 }
 166
 167 int syslog_fixup_facility(int priority) {
 168
 169         if ((priority & LOG_FACMASK) == 0)
 170                 return (priority & LOG_PRIMASK) | LOG_USER;
 171
 172         return priority;
 173 }
 174
 175 size_t syslog_parse_identifier(const char **buf, char **identifier, char **pid) {
 176         const char *p;
 177         char *t;
 178         size_t l, e;
 179
 180         assert(buf);
 181         assert(identifier);
 182         assert(pid);
 183
 184         p = *buf;
 185
 186         p += strspn(p, WHITESPACE);
 187         l = strcspn(p, WHITESPACE);
 188
 189         if (l <= 0 ||
 190             p[l-1] != ':')
 191                 return 0;
 192
 193         e = l;
 194         l--;
 195
 196         if (p[l-1] == ']') {
 197                 size_t k = l-1;
 198
 199                 for (;;) {
 200
 201                         if (p[k] == '[') {
 202                                 t = strndup(p+k+1, l-k-2);
 203                                 if (t)
 204                                         *pid = t;
 205
 206                                 l = k;
 207                                 break;
 208                         }
 209
 210                         if (k == 0)
 211                                 break;
 212
 213                         k--;
 214                 }
 215         }
 216
 217         t = strndup(p, l);
 218         if (t)
 219                 *identifier = t;
 220
 221         if (strchr(WHITESPACE, p[e]))
 222                 e++;
 223         *buf = p + e;
 224         return e;
 225 }
 226
 227 static int syslog_skip_timestamp(const char **buf) {
 228         enum {
 229                 LETTER,
 230                 SPACE,
 231                 NUMBER,
 232                 SPACE_OR_NUMBER,
 233                 COLON
 234         } sequence[] = {
 235                 LETTER, LETTER, LETTER,
 236                 SPACE,
 237                 SPACE_OR_NUMBER, NUMBER,
 238                 SPACE,
 239                 SPACE_OR_NUMBER, NUMBER,
 240                 COLON,
 241                 SPACE_OR_NUMBER, NUMBER,
 242                 COLON,
 243                 SPACE_OR_NUMBER, NUMBER,
 244                 SPACE
 245         };
 246
 247         const char *p, *t;
 248         unsigned i;
 249
 250         assert(buf);
 251         assert(*buf);
 252
 253         for (i = 0, p = *buf; i < ELEMENTSOF(sequence); i++, p++) {
 254                 if (!*p)
 255                         return 0;
 256
 257                 switch (sequence[i]) {
 258
 259                 case SPACE:
 260                         if (*p != ' ')
 261                                 return 0;
 262                         break;
 263
 264                 case SPACE_OR_NUMBER:
 265                         if (*p == ' ')
 266                                 break;
 267
 268                         _fallthrough_;
 269                 case NUMBER:
 270                         if (*p < '0' || *p > '9')
 271                                 return 0;
 272
 273                         break;
 274
 275                 case LETTER:
 276                         if (!(*p >= 'A' && *p <= 'Z') &&
 277                             !(*p >= 'a' && *p <= 'z'))
 278                                 return 0;
 279
 280                         break;
 281
 282                 case COLON:
 283                         if (*p != ':')
 284                                 return 0;
 285                         break;
 286
 287                 }
 288         }
 289
 290         t = *buf;
 291         *buf = p;
 292         return p - t;
 293 }
 294
 295 void server_process_syslog_message(
 296                 Server *s,
 297                 const char *buf,
 298                 size_t raw_len,
 299                 const struct ucred *ucred,
 300                 const struct timeval *tv,
 301                 const char *label,
 302                 size_t label_len) {
 303
 304         char *t, syslog_priority[sizeof("PRIORITY=") + DECIMAL_STR_MAX(int)],
 305                  syslog_facility[sizeof("SYSLOG_FACILITY=") + DECIMAL_STR_MAX(int)];
 306         const char *msg, *syslog_ts, *a;
 307         _cleanup_free_ char *identifier = NULL, *pid = NULL,
 308                 *dummy = NULL, *msg_msg = NULL, *msg_raw = NULL;
 309         int priority = LOG_USER | LOG_INFO, r;
 310         ClientContext *context = NULL;
 311         struct iovec *iovec;
 312         size_t n = 0, m, i, leading_ws, syslog_ts_len;
 313         bool store_raw;
 314
 315         assert(s);
 316         assert(buf);
 317         /* The message cannot be empty. */
 318         assert(raw_len > 0);
 319         /* The buffer NUL-terminated and can be used a string. raw_len is the length
 320          * without the terminating NUL byte, the buffer is actually one bigger. */
 321         assert(buf[raw_len] == '\0');
 322
 323         if (ucred && pid_is_valid(ucred->pid)) {
 324                 r = client_context_get(s, ucred->pid, ucred, label, label_len, NULL, &context);
 325                 if (r < 0)
 326                         log_warning_errno(r, "Failed to retrieve credentials for PID " PID_FMT ", ignoring: %m", ucred->pid);
 327         }
 328
 329         /* We are creating a copy of the message because we want to forward the original message
 330            verbatim to the legacy syslog implementation */
 331         for (i = raw_len; i > 0; i--)
 332                 if (!strchr(WHITESPACE, buf[i-1]))
 333                         break;
 334
 335         leading_ws = strspn(buf, WHITESPACE);
 336
 337         if (i == 0)
 338                 /* The message contains only whitespaces */
 339                 msg = buf + raw_len;
 340         else if (i == raw_len)
 341                 /* Nice! No need to strip anything on the end, let's optimize this a bit */
 342                 msg = buf + leading_ws;
 343         else {
 344                 msg = dummy = new(char, i - leading_ws + 1);
 345                 if (!dummy) {
 346                         log_oom();
 347                         return;
 348                 }
 349
 350                 memcpy(dummy, buf + leading_ws, i - leading_ws);
 351                 dummy[i - leading_ws] = 0;
 352         }
 353
 354         /* We will add the SYSLOG_RAW= field when we stripped anything
 355          * _or_ if the input message contained NUL bytes. */
 356         store_raw = msg != buf || strlen(msg) != raw_len;
 357
 358         syslog_parse_priority(&msg, &priority, true);
 359
 360         if (!client_context_test_priority(context, priority))
 361                 return;
 362
 363         syslog_ts = msg;
 364         syslog_ts_len = syslog_skip_timestamp(&msg);
 365         if (syslog_ts_len == 0)
 366                 /* We failed to parse the full timestamp, store the raw message too */
 367                 store_raw = true;
 368
 369         syslog_parse_identifier(&msg, &identifier, &pid);
 370
 371         if (s->forward_to_syslog)
 372                 forward_syslog_raw(s, priority, buf, raw_len, ucred, tv);
 373
 374         if (s->forward_to_kmsg)
 375                 server_forward_kmsg(s, priority, identifier, msg, ucred);
 376
 377         if (s->forward_to_console)
 378                 server_forward_console(s, priority, identifier, msg, ucred);
 379
 380         if (s->forward_to_wall)
 381                 server_forward_wall(s, priority, identifier, msg, ucred);
 382
 383         m = N_IOVEC_META_FIELDS + 8 + client_context_extra_fields_n_iovec(context);
 384         iovec = newa(struct iovec, m);
 385
 386         iovec[n++] = IOVEC_MAKE_STRING("_TRANSPORT=syslog");
 387
 388         xsprintf(syslog_priority, "PRIORITY=%i", priority & LOG_PRIMASK);
 389         iovec[n++] = IOVEC_MAKE_STRING(syslog_priority);
 390
 391         if (priority & LOG_FACMASK) {
 392                 xsprintf(syslog_facility, "SYSLOG_FACILITY=%i", LOG_FAC(priority));
 393                 iovec[n++] = IOVEC_MAKE_STRING(syslog_facility);
 394         }
 395
 396         if (identifier) {
 397                 a = strjoina("SYSLOG_IDENTIFIER=", identifier);
 398                 iovec[n++] = IOVEC_MAKE_STRING(a);
 399         }
 400
 401         if (pid) {
 402                 a = strjoina("SYSLOG_PID=", pid);
 403                 iovec[n++] = IOVEC_MAKE_STRING(a);
 404         }
 405
 406         if (syslog_ts_len > 0) {
 407                 const size_t hlen = strlen("SYSLOG_TIMESTAMP=");
 408
 409                 t = newa(char, hlen + raw_len);
 410                 memcpy(t, "SYSLOG_TIMESTAMP=", hlen);
 411                 memcpy(t + hlen, syslog_ts, syslog_ts_len);
 412
 413                 iovec[n++] = IOVEC_MAKE(t, hlen + syslog_ts_len);
 414         }
 415
 416         msg_msg = strjoin("MESSAGE=", msg);
 417         if (!msg_msg) {
 418                 log_oom();
 419                 return;
 420         }
 421         iovec[n++] = IOVEC_MAKE_STRING(msg_msg);
 422
 423         if (store_raw) {
 424                 const size_t hlen = strlen("SYSLOG_RAW=");
 425
 426                 msg_raw = new(char, hlen + raw_len);
 427                 if (!msg_raw) {
 428                         log_oom();
 429                         return;
 430                 }
 431
 432                 memcpy(msg_raw, "SYSLOG_RAW=", hlen);
 433                 memcpy(msg_raw + hlen, buf, raw_len);
 434
 435                 iovec[n++] = IOVEC_MAKE(msg_raw, hlen + raw_len);
 436         }
 437
 438         server_dispatch_message(s, iovec, n, m, context, tv, priority, 0);
 439 }
 440
 441 int server_open_syslog_socket(Server *s) {
 442
 443         static const union sockaddr_union sa = {
 444                 .un.sun_family = AF_UNIX,
 445                 .un.sun_path = "/run/systemd/journal/dev-log",
 446         };
 447         static const int one = 1;
 448         int r;
 449
 450         assert(s);
 451
 452         if (s->syslog_fd < 0) {
 453                 s->syslog_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 454                 if (s->syslog_fd < 0)
 455                         return log_error_errno(errno, "socket() failed: %m");
 456
 457                 (void) unlink(sa.un.sun_path);
 458
 459                 r = bind(s->syslog_fd, &sa.sa, SOCKADDR_UN_LEN(sa.un));
 460                 if (r < 0)
 461                         return log_error_errno(errno, "bind(%s) failed: %m", sa.un.sun_path);
 462
 463                 (void) chmod(sa.un.sun_path, 0666);
 464         } else
 465                 fd_nonblock(s->syslog_fd, 1);
 466
 467         r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one));
 468         if (r < 0)
 469                 return log_error_errno(errno, "SO_PASSCRED failed: %m");
 470
 471 #if HAVE_SELINUX
 472         if (mac_selinux_use()) {
 473                 r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_PASSSEC, &one, sizeof(one));
 474                 if (r < 0)
 475                         log_warning_errno(errno, "SO_PASSSEC failed: %m");
 476         }
 477 #endif
 478
 479         r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_TIMESTAMP, &one, sizeof(one));
 480         if (r < 0)
 481                 return log_error_errno(errno, "SO_TIMESTAMP failed: %m");
 482
 483         r = sd_event_add_io(s->event, &s->syslog_event_source, s->syslog_fd, EPOLLIN, server_process_datagram, s);
 484         if (r < 0)
 485                 return log_error_errno(r, "Failed to add syslog server fd to event loop: %m");
 486
 487         r = sd_event_source_set_priority(s->syslog_event_source, SD_EVENT_PRIORITY_NORMAL+5);
 488         if (r < 0)
 489                 return log_error_errno(r, "Failed to adjust syslog event source priority: %m");
 490
 491         return 0;
 492 }
 493
 494 void server_maybe_warn_forward_syslog_missed(Server *s) {
 495         usec_t n;
 496
 497         assert(s);
 498
 499         if (s->n_forward_syslog_missed <= 0)
 500                 return;
 501
 502         n = now(CLOCK_MONOTONIC);
 503         if (s->last_warn_forward_syslog_missed + WARN_FORWARD_SYSLOG_MISSED_USEC > n)
 504                 return;
 505
 506         server_driver_message(s, 0,
 507                               "MESSAGE_ID=" SD_MESSAGE_FORWARD_SYSLOG_MISSED_STR,
 508                               LOG_MESSAGE("Forwarding to syslog missed %u messages.",
 509                                           s->n_forward_syslog_missed),
 510                               NULL);
 511
 512         s->n_forward_syslog_missed = 0;
 513         s->last_warn_forward_syslog_missed = n;
 514 }