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 void syslog_skip_date(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         char *p;
 248         unsigned i;
 249
 250         assert(buf);
 251         assert(*buf);
 252
 253         p = *buf;
 254
 255         for (i = 0; i < ELEMENTSOF(sequence); i++, p++) {
 256
 257                 if (!*p)
 258                         return;
 259
 260                 switch (sequence[i]) {
 261
 262                 case SPACE:
 263                         if (*p != ' ')
 264                                 return;
 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;
 275
 276                         break;
 277
 278                 case LETTER:
 279                         if (!(*p >= 'A' && *p <= 'Z') &&
 280                             !(*p >= 'a' && *p <= 'z'))
 281                                 return;
 282
 283                         break;
 284
 285                 case COLON:
 286                         if (*p != ':')
 287                                 return;
 288                         break;
 289
 290                 }
 291         }
 292
 293         *buf = p;
 294 }
 295
 296 void server_process_syslog_message(
 297                 Server *s,
 298                 const char *buf,
 299                 size_t buf_len,
 300                 const struct ucred *ucred,
 301                 const struct timeval *tv,
 302                 const char *label,
 303                 size_t label_len) {
 304
 305         char syslog_priority[sizeof("PRIORITY=") + DECIMAL_STR_MAX(int)],
 306              syslog_facility[sizeof("SYSLOG_FACILITY=") + DECIMAL_STR_MAX(int)], *msg;
 307         const char *message = NULL, *syslog_identifier = NULL, *syslog_pid = NULL;
 308         _cleanup_free_ char *identifier = NULL, *pid = NULL;
 309         int priority = LOG_USER | LOG_INFO, r;
 310         ClientContext *context = NULL;
 311         struct iovec *iovec;
 312         size_t n = 0, m, i;
 313
 314         assert(s);
 315         assert(buf);
 316
 317         if (ucred && pid_is_valid(ucred->pid)) {
 318                 r = client_context_get(s, ucred->pid, ucred, label, label_len, NULL, &context);
 319                 if (r < 0)
 320                         log_warning_errno(r, "Failed to retrieve credentials for PID " PID_FMT ", ignoring: %m", ucred->pid);
 321         }
 322
 323         /* We are creating copy of the message because we want to forward original message verbatim to the legacy
 324            syslog implementation */
 325         for (i = buf_len; i > 0; i--)
 326                 if (!strchr(WHITESPACE, buf[i-1]))
 327                         break;
 328
 329         msg = newa(char, i + 1);
 330         *((char *) mempcpy(msg, buf, i)) = 0;
 331         msg = skip_leading_chars(msg, WHITESPACE);
 332
 333         syslog_parse_priority((const char **)&msg, &priority, true);
 334
 335         if (!client_context_test_priority(context, priority))
 336                 return;
 337
 338         if (s->forward_to_syslog)
 339                 forward_syslog_raw(s, priority, buf, buf_len, ucred, tv);
 340
 341         syslog_skip_date(&msg);
 342         syslog_parse_identifier((const char**)&msg, &identifier, &pid);
 343
 344         if (s->forward_to_kmsg)
 345                 server_forward_kmsg(s, priority, identifier, msg, ucred);
 346
 347         if (s->forward_to_console)
 348                 server_forward_console(s, priority, identifier, msg, ucred);
 349
 350         if (s->forward_to_wall)
 351                 server_forward_wall(s, priority, identifier, msg, ucred);
 352
 353         m = N_IOVEC_META_FIELDS + 6 + client_context_extra_fields_n_iovec(context);
 354         iovec = newa(struct iovec, m);
 355
 356         iovec[n++] = IOVEC_MAKE_STRING("_TRANSPORT=syslog");
 357
 358         xsprintf(syslog_priority, "PRIORITY=%i", priority & LOG_PRIMASK);
 359         iovec[n++] = IOVEC_MAKE_STRING(syslog_priority);
 360
 361         if (priority & LOG_FACMASK) {
 362                 xsprintf(syslog_facility, "SYSLOG_FACILITY=%i", LOG_FAC(priority));
 363                 iovec[n++] = IOVEC_MAKE_STRING(syslog_facility);
 364         }
 365
 366         if (identifier) {
 367                 syslog_identifier = strjoina("SYSLOG_IDENTIFIER=", identifier);
 368                 iovec[n++] = IOVEC_MAKE_STRING(syslog_identifier);
 369         }
 370
 371         if (pid) {
 372                 syslog_pid = strjoina("SYSLOG_PID=", pid);
 373                 iovec[n++] = IOVEC_MAKE_STRING(syslog_pid);
 374         }
 375
 376         message = strjoina("MESSAGE=", msg);
 377         if (message)
 378                 iovec[n++] = IOVEC_MAKE_STRING(message);
 379
 380         server_dispatch_message(s, iovec, n, m, context, tv, priority, 0);
 381 }
 382
 383 int server_open_syslog_socket(Server *s) {
 384
 385         static const union sockaddr_union sa = {
 386                 .un.sun_family = AF_UNIX,
 387                 .un.sun_path = "/run/systemd/journal/dev-log",
 388         };
 389         static const int one = 1;
 390         int r;
 391
 392         assert(s);
 393
 394         if (s->syslog_fd < 0) {
 395                 s->syslog_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 396                 if (s->syslog_fd < 0)
 397                         return log_error_errno(errno, "socket() failed: %m");
 398
 399                 (void) unlink(sa.un.sun_path);
 400
 401                 r = bind(s->syslog_fd, &sa.sa, SOCKADDR_UN_LEN(sa.un));
 402                 if (r < 0)
 403                         return log_error_errno(errno, "bind(%s) failed: %m", sa.un.sun_path);
 404
 405                 (void) chmod(sa.un.sun_path, 0666);
 406         } else
 407                 fd_nonblock(s->syslog_fd, 1);
 408
 409         r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one));
 410         if (r < 0)
 411                 return log_error_errno(errno, "SO_PASSCRED failed: %m");
 412
 413 #if HAVE_SELINUX
 414         if (mac_selinux_use()) {
 415                 r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_PASSSEC, &one, sizeof(one));
 416                 if (r < 0)
 417                         log_warning_errno(errno, "SO_PASSSEC failed: %m");
 418         }
 419 #endif
 420
 421         r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_TIMESTAMP, &one, sizeof(one));
 422         if (r < 0)
 423                 return log_error_errno(errno, "SO_TIMESTAMP failed: %m");
 424
 425         r = sd_event_add_io(s->event, &s->syslog_event_source, s->syslog_fd, EPOLLIN, server_process_datagram, s);
 426         if (r < 0)
 427                 return log_error_errno(r, "Failed to add syslog server fd to event loop: %m");
 428
 429         r = sd_event_source_set_priority(s->syslog_event_source, SD_EVENT_PRIORITY_NORMAL+5);
 430         if (r < 0)
 431                 return log_error_errno(r, "Failed to adjust syslog event source priority: %m");
 432
 433         return 0;
 434 }
 435
 436 void server_maybe_warn_forward_syslog_missed(Server *s) {
 437         usec_t n;
 438
 439         assert(s);
 440
 441         if (s->n_forward_syslog_missed <= 0)
 442                 return;
 443
 444         n = now(CLOCK_MONOTONIC);
 445         if (s->last_warn_forward_syslog_missed + WARN_FORWARD_SYSLOG_MISSED_USEC > n)
 446                 return;
 447
 448         server_driver_message(s, 0,
 449                               "MESSAGE_ID=" SD_MESSAGE_FORWARD_SYSLOG_MISSED_STR,
 450                               LOG_MESSAGE("Forwarding to syslog missed %u messages.",
 451                                           s->n_forward_syslog_missed),
 452                               NULL);
 453
 454         s->n_forward_syslog_missed = 0;
 455         s->last_warn_forward_syslog_missed = n;
 456 }