summaryrefslogtreecommitdiff
path: root/src/journal/journald-native.c
blob: e427f20e69ed25300b7c3ed04398abda0a9c9cc5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2011 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <stddef.h>
#include <sys/epoll.h>
#include <sys/mman.h>
#include <unistd.h>

#include "fd-util.h"
#include "fs-util.h"
#include "journald-console.h"
#include "journald-kmsg.h"
#include "journald-native.h"
#include "journald-server.h"
#include "journald-syslog.h"
#include "journald-wall.h"
#include "memfd-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "selinux-util.h"
#include "socket-util.h"
#include "string-util.h"

bool valid_user_field(const char *p, size_t l, bool allow_protected) {
        const char *a;

        /* We kinda enforce POSIX syntax recommendations for
           environment variables here, but make a couple of additional
           requirements.

           http://pubs.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap08.html */

        /* No empty field names */
        if (l <= 0)
                return false;

        /* Don't allow names longer than 64 chars */
        if (l > 64)
                return false;

        /* Variables starting with an underscore are protected */
        if (!allow_protected && p[0] == '_')
                return false;

        /* Don't allow digits as first character */
        if (p[0] >= '0' && p[0] <= '9')
                return false;

        /* Only allow A-Z0-9 and '_' */
        for (a = p; a < p + l; a++)
                if ((*a < 'A' || *a > 'Z') &&
                    (*a < '0' || *a > '9') &&
                    *a != '_')
                        return false;

        return true;
}

static bool allow_object_pid(const struct ucred *ucred) {
        return ucred && ucred->uid == 0;
}

void server_process_native_message(
                Server *s,
                const void *buffer, size_t buffer_size,
                const struct ucred *ucred,
                const struct timeval *tv,
                const char *label, size_t label_len) {

        struct iovec *iovec = NULL;
        unsigned n = 0, j, tn = (unsigned) -1;
        const char *p;
        size_t remaining, m = 0, entry_size = 0;
        int priority = LOG_INFO;
        char *identifier = NULL, *message = NULL;
        pid_t object_pid = 0;

        assert(s);
        assert(buffer || buffer_size == 0);

        p = buffer;
        remaining = buffer_size;

        while (remaining > 0) {
                const char *e, *q;

                e = memchr(p, '\n', remaining);

                if (!e) {
                        /* Trailing noise, let's ignore it, and flush what we collected */
                        log_debug("Received message with trailing noise, ignoring.");
                        break;
                }

                if (e == p) {
                        /* Entry separator */

                        if (entry_size + n + 1 > ENTRY_SIZE_MAX) { /* data + separators + trailer */
                                log_debug("Entry is too big with %u properties and %zu bytes, ignoring.", n, entry_size);
                                continue;
                        }

                        server_dispatch_message(s, iovec, n, m, ucred, tv, label, label_len, NULL, priority, object_pid);
                        n = 0;
                        priority = LOG_INFO;
                        entry_size = 0;

                        p++;
                        remaining--;
                        continue;
                }

                if (*p == '.' || *p == '#') {
                        /* Ignore control commands for now, and
                         * comments too. */
                        remaining -= (e - p) + 1;
                        p = e + 1;
                        continue;
                }

                /* A property follows */

                /* n existing properties, 1 new, +1 for _TRANSPORT */
                if (!GREEDY_REALLOC(iovec, m, n + 2 + N_IOVEC_META_FIELDS + N_IOVEC_OBJECT_FIELDS)) {
                        log_oom();
                        break;
                }

                q = memchr(p, '=', e - p);
                if (q) {
                        if (valid_user_field(p, q - p, false)) {
                                size_t l;

                                l = e - p;

                                /* If the field name starts with an
                                 * underscore, skip the variable,
                                 * since that indidates a trusted
                                 * field */
                                iovec[n].iov_base = (char*) p;
                                iovec[n].iov_len = l;
                                entry_size += iovec[n].iov_len;
                                n++;

                                /* We need to determine the priority
                                 * of this entry for the rate limiting
                                 * logic */
                                if (l == 10 &&
                                    startswith(p, "PRIORITY=") &&
                                    p[9] >= '0' && p[9] <= '9')
                                        priority = (priority & LOG_FACMASK) | (p[9] - '0');

                                else if (l == 17 &&
                                         startswith(p, "SYSLOG_FACILITY=") &&
                                         p[16] >= '0' && p[16] <= '9')
                                        priority = (priority & LOG_PRIMASK) | ((p[16] - '0') << 3);

                                else if (l == 18 &&
                                         startswith(p, "SYSLOG_FACILITY=") &&
                                         p[16] >= '0' && p[16] <= '9' &&
                                         p[17] >= '0' && p[17] <= '9')
                                        priority = (priority & LOG_PRIMASK) | (((p[16] - '0')*10 + (p[17] - '0')) << 3);

                                else if (l >= 19 &&
                                         startswith(p, "SYSLOG_IDENTIFIER=")) {
                                        char *t;

                                        t = strndup(p + 18, l - 18);
                                        if (t) {
                                                free(identifier);
                                                identifier = t;
                                        }

                                } else if (l >= 8 &&
                                           startswith(p, "MESSAGE=")) {
                                        char *t;

                                        t = strndup(p + 8, l - 8);
                                        if (t) {
                                                free(message);
                                                message = t;
                                        }

                                } else if (l > strlen("OBJECT_PID=") &&
                                           l < strlen("OBJECT_PID=")  + DECIMAL_STR_MAX(pid_t) &&
                                           startswith(p, "OBJECT_PID=") &&
                                           allow_object_pid(ucred)) {
                                        char buf[DECIMAL_STR_MAX(pid_t)];
                                        memcpy(buf, p + strlen("OBJECT_PID="), l - strlen("OBJECT_PID="));
                                        char_array_0(buf);

                                        /* ignore error */
                                        parse_pid(buf, &object_pid);
                                }
                        }

                        remaining -= (e - p) + 1;
                        p = e + 1;
                        continue;
                } else {
                        le64_t l_le;
                        uint64_t l;
                        char *k;

                        if (remaining < e - p + 1 + sizeof(uint64_t) + 1) {
                                log_debug("Failed to parse message, ignoring.");
                                break;
                        }

                        memcpy(&l_le, e + 1, sizeof(uint64_t));
                        l = le64toh(l_le);

                        if (l > DATA_SIZE_MAX) {
                                log_debug("Received binary data block of %"PRIu64" bytes is too large, ignoring.", l);
                                break;
                        }

                        if ((uint64_t) remaining < e - p + 1 + sizeof(uint64_t) + l + 1 ||
                            e[1+sizeof(uint64_t)+l] != '\n') {
                                log_debug("Failed to parse message, ignoring.");
                                break;
                        }

                        k = malloc((e - p) + 1 + l);
                        if (!k) {
                                log_oom();
                                break;
                        }

                        memcpy(k, p, e - p);
                        k[e - p] = '=';
                        memcpy(k + (e - p) + 1, e + 1 + sizeof(uint64_t), l);

                        if (valid_user_field(p, e - p, false)) {
                                iovec[n].iov_base = k;
                                iovec[n].iov_len = (e - p) + 1 + l;
                                entry_size += iovec[n].iov_len;
                                n++;
                        } else
                                free(k);

                        remaining -= (e - p) + 1 + sizeof(uint64_t) + l + 1;
                        p = e + 1 + sizeof(uint64_t) + l + 1;
                }
        }

        if (n <= 0)
                goto finish;

        tn = n++;
        IOVEC_SET_STRING(iovec[tn], "_TRANSPORT=journal");
        entry_size += strlen("_TRANSPORT=journal");

        if (entry_size + n + 1 > ENTRY_SIZE_MAX) { /* data + separators + trailer */
                log_debug("Entry is too big with %u properties and %zu bytes, ignoring.",
                          n, entry_size);
                goto finish;
        }

        if (message) {
                if (s->forward_to_syslog)
                        server_forward_syslog(s, priority, identifier, message, ucred, tv);

                if (s->forward_to_kmsg)
                        server_forward_kmsg(s, priority, identifier, message, ucred);

                if (s->forward_to_console)
                        server_forward_console(s, priority, identifier, message, ucred);

                if (s->forward_to_wall)
                        server_forward_wall(s, priority, identifier, message, ucred);
        }

        server_dispatch_message(s, iovec, n, m, ucred, tv, label, label_len, NULL, priority, object_pid);

finish:
        for (j = 0; j < n; j++)  {
                if (j == tn)
                        continue;

                if (iovec[j].iov_base < buffer ||
                    (const uint8_t*) iovec[j].iov_base >= (const uint8_t*) buffer + buffer_size)
                        free(iovec[j].iov_base);
        }

        free(iovec);
        free(identifier);
        free(message);
}

void server_process_native_file(
                Server *s,
                int fd,
                const struct ucred *ucred,
                const struct timeval *tv,
                const char *label, size_t label_len) {

        struct stat st;
        bool sealed;
        int r;

        /* Data is in the passed fd, since it didn't fit in a
         * datagram. */

        assert(s);
        assert(fd >= 0);

        /* If it's a memfd, check if it is sealed. If so, we can just
         * use map it and use it, and do not need to copy the data
         * out. */
        sealed = memfd_get_sealed(fd) > 0;

        if (!sealed && (!ucred || ucred->uid != 0)) {
                _cleanup_free_ char *sl = NULL, *k = NULL;
                const char *e;

                /* If this is not a sealed memfd, and the peer is unknown or
                 * unprivileged, then verify the path. */

                if (asprintf(&sl, "/proc/self/fd/%i", fd) < 0) {
                        log_oom();
                        return;
                }

                r = readlink_malloc(sl, &k);
                if (r < 0) {
                        log_error_errno(errno, "readlink(%s) failed: %m", sl);
                        return;
                }

                e = path_startswith(k, "/dev/shm/");
                if (!e)
                        e = path_startswith(k, "/tmp/");
                if (!e)
                        e = path_startswith(k, "/var/tmp/");
                if (!e) {
                        log_error("Received file outside of allowed directories. Refusing.");
                        return;
                }

                if (!filename_is_valid(e)) {
                        log_error("Received file in subdirectory of allowed directories. Refusing.");
                        return;
                }
        }

        if (fstat(fd, &st) < 0) {
                log_error_errno(errno, "Failed to stat passed file, ignoring: %m");
                return;
        }

        if (!S_ISREG(st.st_mode)) {
                log_error("File passed is not regular. Ignoring.");
                return;
        }

        if (st.st_size <= 0)
                return;

        if (st.st_size > ENTRY_SIZE_MAX) {
                log_error("File passed too large. Ignoring.");
                return;
        }

        if (sealed) {
                void *p;
                size_t ps;

                /* The file is sealed, we can just map it and use it. */

                ps = PAGE_ALIGN(st.st_size);
                p = mmap(NULL, ps, PROT_READ, MAP_PRIVATE, fd, 0);
                if (p == MAP_FAILED) {
                        log_error_errno(errno, "Failed to map memfd, ignoring: %m");
                        return;
                }

                server_process_native_message(s, p, st.st_size, ucred, tv, label, label_len);
                assert_se(munmap(p, ps) >= 0);
        } else {
                _cleanup_free_ void *p = NULL;
                ssize_t n;

                /* The file is not sealed, we can't map the file here, since
                 * clients might then truncate it and trigger a SIGBUS for
                 * us. So let's stupidly read it */

                p = malloc(st.st_size);
                if (!p) {
                        log_oom();
                        return;
                }

                n = pread(fd, p, st.st_size, 0);
                if (n < 0)
                        log_error_errno(n, "Failed to read file, ignoring: %m");
                else if (n > 0)
                        server_process_native_message(s, p, n, ucred, tv, label, label_len);
        }
}

int server_open_native_socket(Server*s) {
        static const int one = 1;
        int r;

        assert(s);

        if (s->native_fd < 0) {
                union sockaddr_union sa = {
                        .un.sun_family = AF_UNIX,
                        .un.sun_path = "/run/systemd/journal/socket",
                };

                s->native_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
                if (s->native_fd < 0)
                        return log_error_errno(errno, "socket() failed: %m");

                unlink(sa.un.sun_path);

                r = bind(s->native_fd, &sa.sa, offsetof(union sockaddr_union, un.sun_path) + strlen(sa.un.sun_path));
                if (r < 0)
                        return log_error_errno(errno, "bind(%s) failed: %m", sa.un.sun_path);

                (void) chmod(sa.un.sun_path, 0666);
        } else
                fd_nonblock(s->native_fd, 1);

        r = setsockopt(s->native_fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one));
        if (r < 0)
                return log_error_errno(errno, "SO_PASSCRED failed: %m");

#ifdef HAVE_SELINUX
        if (mac_selinux_use()) {
                r = setsockopt(s->native_fd, SOL_SOCKET, SO_PASSSEC, &one, sizeof(one));
                if (r < 0)
                        log_warning_errno(errno, "SO_PASSSEC failed: %m");
        }
#endif

        r = setsockopt(s->native_fd, SOL_SOCKET, SO_TIMESTAMP, &one, sizeof(one));
        if (r < 0)
                return log_error_errno(errno, "SO_TIMESTAMP failed: %m");

        r = sd_event_add_io(s->event, &s->native_event_source, s->native_fd, EPOLLIN, server_process_datagram, s);
        if (r < 0)
                return log_error_errno(r, "Failed to add native server fd to event loop: %m");

        return 0;
}