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 (l > 0 && 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         /* Single space is used as separator */
 222         if (p[e] != '\0' && strchr(WHITESPACE, p[e]))
 223                 e++;
 224
 225         l = (p - *buf) + e;
 226         *buf = p + e;
 227         return l;
 228 }
 229
 230 static int syslog_skip_timestamp(const char **buf) {
 231         enum {
 232                 LETTER,
 233                 SPACE,
 234                 NUMBER,
 235                 SPACE_OR_NUMBER,
 236                 COLON
 237         } sequence[] = {
 238                 LETTER, LETTER, LETTER,
 239                 SPACE,
 240                 SPACE_OR_NUMBER, NUMBER,
 241                 SPACE,
 242                 SPACE_OR_NUMBER, NUMBER,
 243                 COLON,
 244                 SPACE_OR_NUMBER, NUMBER,
 245                 COLON,
 246                 SPACE_OR_NUMBER, NUMBER,
 247                 SPACE
 248         };
 249
 250         const char *p, *t;
 251         unsigned i;
 252
 253         assert(buf);
 254         assert(*buf);
 255
 256         for (i = 0, p = *buf; i < ELEMENTSOF(sequence); i++, p++) {
 257                 if (!*p)
 258                         return 0;
 259
 260                 switch (sequence[i]) {
 261
 262                 case SPACE:
 263                         if (*p != ' ')
 264                                 return 0;
 265                         break;
 266
 267                 case SPACE_OR_NUMBER:
 268                         if (*p == ' ')
 269                                 break;
 270
 271                         _fallthrough_;
 272                 case NUMBER:
 273                         if (*p < '0' || *p > '9')
 274                                 return 0;
 275
 276                         break;
 277
 278                 case LETTER:
 279                         if (!(*p >= 'A' && *p <= 'Z') &&
 280                             !(*p >= 'a' && *p <= 'z'))
 281                                 return 0;
 282
 283                         break;
 284
 285                 case COLON:
 286                         if (*p != ':')
 287                                 return 0;
 288                         break;
 289
 290                 }
 291         }
 292
 293         t = *buf;
 294         *buf = p;
 295         return p - t;
 296 }
 297
 298 void server_process_syslog_message(
 299                 Server *s,
 300                 const char *buf,
 301                 size_t raw_len,
 302                 const struct ucred *ucred,
 303                 const struct timeval *tv,
 304                 const char *label,
 305                 size_t label_len) {
 306
 307         char *t, syslog_priority[sizeof("PRIORITY=") + DECIMAL_STR_MAX(int)],
 308                  syslog_facility[sizeof("SYSLOG_FACILITY=") + DECIMAL_STR_MAX(int)];
 309         const char *msg, *syslog_ts, *a;
 310         _cleanup_free_ char *identifier = NULL, *pid = NULL,
 311                 *dummy = NULL, *msg_msg = NULL, *msg_raw = NULL;
 312         int priority = LOG_USER | LOG_INFO, r;
 313         ClientContext *context = NULL;
 314         struct iovec *iovec;
 315         size_t n = 0, m, i, leading_ws, syslog_ts_len;
 316         bool store_raw;
 317
 318         assert(s);
 319         assert(buf);
 320         /* The message cannot be empty. */
 321         assert(raw_len > 0);
 322         /* The buffer NUL-terminated and can be used a string. raw_len is the length
 323          * without the terminating NUL byte, the buffer is actually one bigger. */
 324         assert(buf[raw_len] == '\0');
 325
 326         if (ucred && pid_is_valid(ucred->pid)) {
 327                 r = client_context_get(s, ucred->pid, ucred, label, label_len, NULL, &context);
 328                 if (r < 0)
 329                         log_warning_errno(r, "Failed to retrieve credentials for PID " PID_FMT ", ignoring: %m", ucred->pid);
 330         }
 331
 332         /* We are creating a copy of the message because we want to forward the original message
 333            verbatim to the legacy syslog implementation */
 334         for (i = raw_len; i > 0; i--)
 335                 if (!strchr(WHITESPACE, buf[i-1]))
 336                         break;
 337
 338         leading_ws = strspn(buf, WHITESPACE);
 339
 340         if (i == 0)
 341                 /* The message contains only whitespaces */
 342                 msg = buf + raw_len;
 343         else if (i == raw_len)
 344                 /* Nice! No need to strip anything on the end, let's optimize this a bit */
 345                 msg = buf + leading_ws;
 346         else {
 347                 msg = dummy = new(char, i - leading_ws + 1);
 348                 if (!dummy) {
 349                         log_oom();
 350                         return;
 351                 }
 352
 353                 memcpy(dummy, buf + leading_ws, i - leading_ws);
 354                 dummy[i - leading_ws] = 0;
 355         }
 356
 357         /* We will add the SYSLOG_RAW= field when we stripped anything
 358          * _or_ if the input message contained NUL bytes. */
 359         store_raw = msg != buf || strlen(msg) != raw_len;
 360
 361         syslog_parse_priority(&msg, &priority, true);
 362
 363         if (!client_context_test_priority(context, priority))
 364                 return;
 365
 366         syslog_ts = msg;
 367         syslog_ts_len = syslog_skip_timestamp(&msg);
 368         if (syslog_ts_len == 0)
 369                 /* We failed to parse the full timestamp, store the raw message too */
 370                 store_raw = true;
 371
 372         syslog_parse_identifier(&msg, &identifier, &pid);
 373
 374         if (s->forward_to_syslog)
 375                 forward_syslog_raw(s, priority, buf, raw_len, ucred, tv);
 376
 377         if (s->forward_to_kmsg)
 378                 server_forward_kmsg(s, priority, identifier, msg, ucred);
 379
 380         if (s->forward_to_console)
 381                 server_forward_console(s, priority, identifier, msg, ucred);
 382
 383         if (s->forward_to_wall)
 384                 server_forward_wall(s, priority, identifier, msg, ucred);
 385
 386         m = N_IOVEC_META_FIELDS + 8 + client_context_extra_fields_n_iovec(context);
 387         iovec = newa(struct iovec, m);
 388
 389         iovec[n++] = IOVEC_MAKE_STRING("_TRANSPORT=syslog");
 390
 391         xsprintf(syslog_priority, "PRIORITY=%i", priority & LOG_PRIMASK);
 392         iovec[n++] = IOVEC_MAKE_STRING(syslog_priority);
 393
 394         if (priority & LOG_FACMASK) {
 395                 xsprintf(syslog_facility, "SYSLOG_FACILITY=%i", LOG_FAC(priority));
 396                 iovec[n++] = IOVEC_MAKE_STRING(syslog_facility);
 397         }
 398
 399         if (identifier) {
 400                 a = strjoina("SYSLOG_IDENTIFIER=", identifier);
 401                 iovec[n++] = IOVEC_MAKE_STRING(a);
 402         }
 403
 404         if (pid) {
 405                 a = strjoina("SYSLOG_PID=", pid);
 406                 iovec[n++] = IOVEC_MAKE_STRING(a);
 407         }
 408
 409         if (syslog_ts_len > 0) {
 410                 const size_t hlen = STRLEN("SYSLOG_TIMESTAMP=");
 411
 412                 t = newa(char, hlen + syslog_ts_len);
 413                 memcpy(t, "SYSLOG_TIMESTAMP=", hlen);
 414                 memcpy(t + hlen, syslog_ts, syslog_ts_len);
 415
 416                 iovec[n++] = IOVEC_MAKE(t, hlen + syslog_ts_len);
 417         }
 418
 419         msg_msg = strjoin("MESSAGE=", msg);
 420         if (!msg_msg) {
 421                 log_oom();
 422                 return;
 423         }
 424         iovec[n++] = IOVEC_MAKE_STRING(msg_msg);
 425
 426         if (store_raw) {
 427                 const size_t hlen = STRLEN("SYSLOG_RAW=");
 428
 429                 msg_raw = new(char, hlen + raw_len);
 430                 if (!msg_raw) {
 431                         log_oom();
 432                         return;
 433                 }
 434
 435                 memcpy(msg_raw, "SYSLOG_RAW=", hlen);
 436                 memcpy(msg_raw + hlen, buf, raw_len);
 437
 438                 iovec[n++] = IOVEC_MAKE(msg_raw, hlen + raw_len);
 439         }
 440
 441         server_dispatch_message(s, iovec, n, m, context, tv, priority, 0);
 442 }
 443
 444 int server_open_syslog_socket(Server *s) {
 445
 446         static const union sockaddr_union sa = {
 447                 .un.sun_family = AF_UNIX,
 448                 .un.sun_path = "/run/systemd/journal/dev-log",
 449         };
 450         int r;
 451
 452         assert(s);
 453
 454         if (s->syslog_fd < 0) {
 455                 s->syslog_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 456                 if (s->syslog_fd < 0)
 457                         return log_error_errno(errno, "socket() failed: %m");
 458
 459                 (void) sockaddr_un_unlink(&sa.un);
 460
 461                 r = bind(s->syslog_fd, &sa.sa, SOCKADDR_UN_LEN(sa.un));
 462                 if (r < 0)
 463                         return log_error_errno(errno, "bind(%s) failed: %m", sa.un.sun_path);
 464
 465                 (void) chmod(sa.un.sun_path, 0666);
 466         } else
 467                 (void) fd_nonblock(s->syslog_fd, true);
 468
 469         r = setsockopt_int(s->syslog_fd, SOL_SOCKET, SO_PASSCRED, true);
 470         if (r < 0)
 471                 return log_error_errno(r, "SO_PASSCRED failed: %m");
 472
 473 #if HAVE_SELINUX
 474         if (mac_selinux_use()) {
 475                 r = setsockopt_int(s->syslog_fd, SOL_SOCKET, SO_PASSSEC, true);
 476                 if (r < 0)
 477                         log_warning_errno(r, "SO_PASSSEC failed: %m");
 478         }
 479 #endif
 480
 481         r = setsockopt_int(s->syslog_fd, SOL_SOCKET, SO_TIMESTAMP, true);
 482         if (r < 0)
 483                 return log_error_errno(r, "SO_TIMESTAMP failed: %m");
 484
 485         r = sd_event_add_io(s->event, &s->syslog_event_source, s->syslog_fd, EPOLLIN, server_process_datagram, s);
 486         if (r < 0)
 487                 return log_error_errno(r, "Failed to add syslog server fd to event loop: %m");
 488
 489         r = sd_event_source_set_priority(s->syslog_event_source, SD_EVENT_PRIORITY_NORMAL+5);
 490         if (r < 0)
 491                 return log_error_errno(r, "Failed to adjust syslog event source priority: %m");
 492
 493         return 0;
 494 }
 495
 496 void server_maybe_warn_forward_syslog_missed(Server *s) {
 497         usec_t n;
 498
 499         assert(s);
 500
 501         if (s->n_forward_syslog_missed <= 0)
 502                 return;
 503
 504         n = now(CLOCK_MONOTONIC);
 505         if (s->last_warn_forward_syslog_missed + WARN_FORWARD_SYSLOG_MISSED_USEC > n)
 506                 return;
 507
 508         server_driver_message(s, 0,
 509                               "MESSAGE_ID=" SD_MESSAGE_FORWARD_SYSLOG_MISSED_STR,
 510                               LOG_MESSAGE("Forwarding to syslog missed %u messages.",
 511                                           s->n_forward_syslog_missed),
 512                               NULL);
 513
 514         s->n_forward_syslog_missed = 0;
 515         s->last_warn_forward_syslog_missed = n;
 516 }