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         tm = localtime(&t);
 138         if (!tm)
 139                 return;
 140         if (strftime(header_time, sizeof(header_time), "%h %e %T ", tm) <= 0)
 141                 return;
 142         iovec[n++] = IOVEC_MAKE_STRING(header_time);
 143
 144         /* Third: identifier and PID */
 145         if (ucred) {
 146                 if (!identifier) {
 147                         get_process_comm(ucred->pid, &ident_buf);
 148                         identifier = ident_buf;
 149                 }
 150
 151                 xsprintf(header_pid, "["PID_FMT"]: ", ucred->pid);
 152
 153                 if (identifier)
 154                         iovec[n++] = IOVEC_MAKE_STRING(identifier);
 155
 156                 iovec[n++] = IOVEC_MAKE_STRING(header_pid);
 157         } else if (identifier) {
 158                 iovec[n++] = IOVEC_MAKE_STRING(identifier);
 159                 iovec[n++] = IOVEC_MAKE_STRING(": ");
 160         }
 161
 162         /* Fourth: message */
 163         iovec[n++] = IOVEC_MAKE_STRING(message);
 164
 165         forward_syslog_iovec(s, iovec, n, ucred, tv);
 166 }
 167
 168 int syslog_fixup_facility(int priority) {
 169
 170         if ((priority & LOG_FACMASK) == 0)
 171                 return (priority & LOG_PRIMASK) | LOG_USER;
 172
 173         return priority;
 174 }
 175
 176 size_t syslog_parse_identifier(const char **buf, char **identifier, char **pid) {
 177         const char *p;
 178         char *t;
 179         size_t l, e;
 180
 181         assert(buf);
 182         assert(identifier);
 183         assert(pid);
 184
 185         p = *buf;
 186
 187         p += strspn(p, WHITESPACE);
 188         l = strcspn(p, WHITESPACE);
 189
 190         if (l <= 0 ||
 191             p[l-1] != ':')
 192                 return 0;
 193
 194         e = l;
 195         l--;
 196
 197         if (p[l-1] == ']') {
 198                 size_t k = l-1;
 199
 200                 for (;;) {
 201
 202                         if (p[k] == '[') {
 203                                 t = strndup(p+k+1, l-k-2);
 204                                 if (t)
 205                                         *pid = t;
 206
 207                                 l = k;
 208                                 break;
 209                         }
 210
 211                         if (k == 0)
 212                                 break;
 213
 214                         k--;
 215                 }
 216         }
 217
 218         t = strndup(p, l);
 219         if (t)
 220                 *identifier = t;
 221
 222         if (strchr(WHITESPACE, p[e]))
 223                 e++;
 224         *buf = p + e;
 225         return e;
 226 }
 227
 228 static void syslog_skip_date(const char **buf) {
 229         enum {
 230                 LETTER,
 231                 SPACE,
 232                 NUMBER,
 233                 SPACE_OR_NUMBER,
 234                 COLON
 235         } sequence[] = {
 236                 LETTER, LETTER, LETTER,
 237                 SPACE,
 238                 SPACE_OR_NUMBER, NUMBER,
 239                 SPACE,
 240                 SPACE_OR_NUMBER, NUMBER,
 241                 COLON,
 242                 SPACE_OR_NUMBER, NUMBER,
 243                 COLON,
 244                 SPACE_OR_NUMBER, NUMBER,
 245                 SPACE
 246         };
 247
 248         const char *p;
 249         unsigned i;
 250
 251         assert(buf);
 252         assert(*buf);
 253
 254         p = *buf;
 255
 256         for (i = 0; i < ELEMENTSOF(sequence); i++, p++) {
 257
 258                 if (!*p)
 259                         return;
 260
 261                 switch (sequence[i]) {
 262
 263                 case SPACE:
 264                         if (*p != ' ')
 265                                 return;
 266                         break;
 267
 268                 case SPACE_OR_NUMBER:
 269                         if (*p == ' ')
 270                                 break;
 271
 272                         _fallthrough_;
 273                 case NUMBER:
 274                         if (*p < '0' || *p > '9')
 275                                 return;
 276
 277                         break;
 278
 279                 case LETTER:
 280                         if (!(*p >= 'A' && *p <= 'Z') &&
 281                             !(*p >= 'a' && *p <= 'z'))
 282                                 return;
 283
 284                         break;
 285
 286                 case COLON:
 287                         if (*p != ':')
 288                                 return;
 289                         break;
 290
 291                 }
 292         }
 293
 294         *buf = p;
 295 }
 296
 297 void server_process_syslog_message(
 298                 Server *s,
 299                 const char *buf,
 300                 size_t raw_len,
 301                 const struct ucred *ucred,
 302                 const struct timeval *tv,
 303                 const char *label,
 304                 size_t label_len) {
 305
 306         char syslog_priority[sizeof("PRIORITY=") + DECIMAL_STR_MAX(int)],
 307              syslog_facility[sizeof("SYSLOG_FACILITY=") + DECIMAL_STR_MAX(int)];
 308         const char *message = NULL, *syslog_identifier = NULL, *syslog_pid = NULL, *msg;
 309         _cleanup_free_ char *identifier = NULL, *pid = NULL;
 310         int priority = LOG_USER | LOG_INFO, r;
 311         ClientContext *context = NULL;
 312         struct iovec *iovec;
 313         size_t n = 0, m, i, leading_ws;
 314         bool store_raw;
 315
 316         assert(s);
 317         assert(buf);
 318         /* The message cannot be empty. */
 319         assert(raw_len > 0);
 320         /* The buffer NUL-terminated and can be used a string. raw_len is the length
 321          * without the terminating NUL byte, the buffer is actually one bigger. */
 322         assert(buf[raw_len] == '\0');
 323
 324         if (ucred && pid_is_valid(ucred->pid)) {
 325                 r = client_context_get(s, ucred->pid, ucred, label, label_len, NULL, &context);
 326                 if (r < 0)
 327                         log_warning_errno(r, "Failed to retrieve credentials for PID " PID_FMT ", ignoring: %m", ucred->pid);
 328         }
 329
 330         /* We are creating a copy of the message because we want to forward the original message
 331            verbatim to the legacy syslog implementation */
 332         for (i = raw_len; i > 0; i--)
 333                 if (!strchr(WHITESPACE, buf[i-1]))
 334                         break;
 335
 336         leading_ws = strspn(buf, WHITESPACE);
 337
 338         if (i == raw_len)
 339                 /* Nice! No need to strip anything on the end, let's optimize this a bit */
 340                 msg = buf + leading_ws;
 341         else {
 342                 char *t;
 343
 344                 msg = t = newa(char, i - leading_ws + 1);
 345                 memcpy(t, buf + leading_ws, i - leading_ws);
 346                 t[i - leading_ws] = 0;
 347         }
 348
 349         /* We will add the SYSLOG_RAW= field when we stripped anything
 350          * _or_ if the input message contained NUL bytes. */
 351         store_raw = msg != buf || strlen(msg) != raw_len;
 352
 353         syslog_parse_priority(&msg, &priority, true);
 354
 355         if (!client_context_test_priority(context, priority))
 356                 return;
 357
 358         syslog_skip_date(&msg);
 359         syslog_parse_identifier(&msg, &identifier, &pid);
 360
 361         if (s->forward_to_syslog)
 362                 forward_syslog_raw(s, priority, buf, raw_len, ucred, tv);
 363
 364         if (s->forward_to_kmsg)
 365                 server_forward_kmsg(s, priority, identifier, msg, ucred);
 366
 367         if (s->forward_to_console)
 368                 server_forward_console(s, priority, identifier, msg, ucred);
 369
 370         if (s->forward_to_wall)
 371                 server_forward_wall(s, priority, identifier, msg, ucred);
 372
 373         m = N_IOVEC_META_FIELDS + 7 + client_context_extra_fields_n_iovec(context);
 374         iovec = newa(struct iovec, m);
 375
 376         iovec[n++] = IOVEC_MAKE_STRING("_TRANSPORT=syslog");
 377
 378         xsprintf(syslog_priority, "PRIORITY=%i", priority & LOG_PRIMASK);
 379         iovec[n++] = IOVEC_MAKE_STRING(syslog_priority);
 380
 381         if (priority & LOG_FACMASK) {
 382                 xsprintf(syslog_facility, "SYSLOG_FACILITY=%i", LOG_FAC(priority));
 383                 iovec[n++] = IOVEC_MAKE_STRING(syslog_facility);
 384         }
 385
 386         if (identifier) {
 387                 syslog_identifier = strjoina("SYSLOG_IDENTIFIER=", identifier);
 388                 iovec[n++] = IOVEC_MAKE_STRING(syslog_identifier);
 389         }
 390
 391         if (pid) {
 392                 syslog_pid = strjoina("SYSLOG_PID=", pid);
 393                 iovec[n++] = IOVEC_MAKE_STRING(syslog_pid);
 394         }
 395
 396         message = strjoina("MESSAGE=", msg);
 397         iovec[n++] = IOVEC_MAKE_STRING(message);
 398
 399         if (store_raw) {
 400                 const size_t hlen = strlen("SYSLOG_RAW=");
 401                 char *t;
 402
 403                 t = newa(char, hlen + raw_len);
 404                 memcpy(t, "SYSLOG_RAW=", hlen);
 405                 memcpy(t + hlen, buf, raw_len);
 406
 407                 iovec[n++] = IOVEC_MAKE(t, hlen + raw_len);
 408         }
 409
 410         server_dispatch_message(s, iovec, n, m, context, tv, priority, 0);
 411 }
 412
 413 int server_open_syslog_socket(Server *s) {
 414
 415         static const union sockaddr_union sa = {
 416                 .un.sun_family = AF_UNIX,
 417                 .un.sun_path = "/run/systemd/journal/dev-log",
 418         };
 419         static const int one = 1;
 420         int r;
 421
 422         assert(s);
 423
 424         if (s->syslog_fd < 0) {
 425                 s->syslog_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 426                 if (s->syslog_fd < 0)
 427                         return log_error_errno(errno, "socket() failed: %m");
 428
 429                 (void) unlink(sa.un.sun_path);
 430
 431                 r = bind(s->syslog_fd, &sa.sa, SOCKADDR_UN_LEN(sa.un));
 432                 if (r < 0)
 433                         return log_error_errno(errno, "bind(%s) failed: %m", sa.un.sun_path);
 434
 435                 (void) chmod(sa.un.sun_path, 0666);
 436         } else
 437                 fd_nonblock(s->syslog_fd, 1);
 438
 439         r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one));
 440         if (r < 0)
 441                 return log_error_errno(errno, "SO_PASSCRED failed: %m");
 442
 443 #if HAVE_SELINUX
 444         if (mac_selinux_use()) {
 445                 r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_PASSSEC, &one, sizeof(one));
 446                 if (r < 0)
 447                         log_warning_errno(errno, "SO_PASSSEC failed: %m");
 448         }
 449 #endif
 450
 451         r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_TIMESTAMP, &one, sizeof(one));
 452         if (r < 0)
 453                 return log_error_errno(errno, "SO_TIMESTAMP failed: %m");
 454
 455         r = sd_event_add_io(s->event, &s->syslog_event_source, s->syslog_fd, EPOLLIN, server_process_datagram, s);
 456         if (r < 0)
 457                 return log_error_errno(r, "Failed to add syslog server fd to event loop: %m");
 458
 459         r = sd_event_source_set_priority(s->syslog_event_source, SD_EVENT_PRIORITY_NORMAL+5);
 460         if (r < 0)
 461                 return log_error_errno(r, "Failed to adjust syslog event source priority: %m");
 462
 463         return 0;
 464 }
 465
 466 void server_maybe_warn_forward_syslog_missed(Server *s) {
 467         usec_t n;
 468
 469         assert(s);
 470
 471         if (s->n_forward_syslog_missed <= 0)
 472                 return;
 473
 474         n = now(CLOCK_MONOTONIC);
 475         if (s->last_warn_forward_syslog_missed + WARN_FORWARD_SYSLOG_MISSED_USEC > n)
 476                 return;
 477
 478         server_driver_message(s, 0,
 479                               "MESSAGE_ID=" SD_MESSAGE_FORWARD_SYSLOG_MISSED_STR,
 480                               LOG_MESSAGE("Forwarding to syslog missed %u messages.",
 481                                           s->n_forward_syslog_missed),
 482                               NULL);
 483
 484         s->n_forward_syslog_missed = 0;
 485         s->last_warn_forward_syslog_missed = n;
 486 }