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663996b3 MS |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2012 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <fcntl.h> | |
23 | #include <sys/mman.h> | |
24 | ||
25 | #include "journal-def.h" | |
26 | #include "journal-file.h" | |
27 | #include "journal-authenticate.h" | |
28 | #include "fsprg.h" | |
29 | ||
30 | static uint64_t journal_file_tag_seqnum(JournalFile *f) { | |
31 | uint64_t r; | |
32 | ||
33 | assert(f); | |
34 | ||
35 | r = le64toh(f->header->n_tags) + 1; | |
36 | f->header->n_tags = htole64(r); | |
37 | ||
38 | return r; | |
39 | } | |
40 | ||
41 | int journal_file_append_tag(JournalFile *f) { | |
42 | Object *o; | |
43 | uint64_t p; | |
44 | int r; | |
45 | ||
46 | assert(f); | |
47 | ||
48 | if (!f->seal) | |
49 | return 0; | |
50 | ||
51 | if (!f->hmac_running) | |
52 | return 0; | |
53 | ||
54 | assert(f->hmac); | |
55 | ||
56 | r = journal_file_append_object(f, OBJECT_TAG, sizeof(struct TagObject), &o, &p); | |
57 | if (r < 0) | |
58 | return r; | |
59 | ||
60 | o->tag.seqnum = htole64(journal_file_tag_seqnum(f)); | |
61 | o->tag.epoch = htole64(FSPRG_GetEpoch(f->fsprg_state)); | |
62 | ||
60f067b4 | 63 | log_debug("Writing tag %"PRIu64" for epoch %"PRIu64"", |
14228c0d MB |
64 | le64toh(o->tag.seqnum), |
65 | FSPRG_GetEpoch(f->fsprg_state)); | |
663996b3 MS |
66 | |
67 | /* Add the tag object itself, so that we can protect its | |
68 | * header. This will exclude the actual hash value in it */ | |
69 | r = journal_file_hmac_put_object(f, OBJECT_TAG, o, p); | |
70 | if (r < 0) | |
71 | return r; | |
72 | ||
73 | /* Get the HMAC tag and store it in the object */ | |
74 | memcpy(o->tag.tag, gcry_md_read(f->hmac, 0), TAG_LENGTH); | |
75 | f->hmac_running = false; | |
76 | ||
77 | return 0; | |
78 | } | |
79 | ||
80 | int journal_file_hmac_start(JournalFile *f) { | |
81 | uint8_t key[256 / 8]; /* Let's pass 256 bit from FSPRG to HMAC */ | |
82 | assert(f); | |
83 | ||
84 | if (!f->seal) | |
85 | return 0; | |
86 | ||
87 | if (f->hmac_running) | |
88 | return 0; | |
89 | ||
90 | /* Prepare HMAC for next cycle */ | |
91 | gcry_md_reset(f->hmac); | |
92 | FSPRG_GetKey(f->fsprg_state, key, sizeof(key), 0); | |
93 | gcry_md_setkey(f->hmac, key, sizeof(key)); | |
94 | ||
95 | f->hmac_running = true; | |
96 | ||
97 | return 0; | |
98 | } | |
99 | ||
100 | static int journal_file_get_epoch(JournalFile *f, uint64_t realtime, uint64_t *epoch) { | |
101 | uint64_t t; | |
102 | ||
103 | assert(f); | |
104 | assert(epoch); | |
105 | assert(f->seal); | |
106 | ||
107 | if (f->fss_start_usec == 0 || | |
108 | f->fss_interval_usec == 0) | |
109 | return -ENOTSUP; | |
110 | ||
111 | if (realtime < f->fss_start_usec) | |
112 | return -ESTALE; | |
113 | ||
114 | t = realtime - f->fss_start_usec; | |
115 | t = t / f->fss_interval_usec; | |
116 | ||
117 | *epoch = t; | |
118 | return 0; | |
119 | } | |
120 | ||
121 | static int journal_file_fsprg_need_evolve(JournalFile *f, uint64_t realtime) { | |
122 | uint64_t goal, epoch; | |
123 | int r; | |
124 | assert(f); | |
125 | ||
126 | if (!f->seal) | |
127 | return 0; | |
128 | ||
129 | r = journal_file_get_epoch(f, realtime, &goal); | |
130 | if (r < 0) | |
131 | return r; | |
132 | ||
133 | epoch = FSPRG_GetEpoch(f->fsprg_state); | |
134 | if (epoch > goal) | |
135 | return -ESTALE; | |
136 | ||
137 | return epoch != goal; | |
138 | } | |
139 | ||
140 | int journal_file_fsprg_evolve(JournalFile *f, uint64_t realtime) { | |
141 | uint64_t goal, epoch; | |
142 | int r; | |
143 | ||
144 | assert(f); | |
145 | ||
146 | if (!f->seal) | |
147 | return 0; | |
148 | ||
149 | r = journal_file_get_epoch(f, realtime, &goal); | |
150 | if (r < 0) | |
151 | return r; | |
152 | ||
153 | epoch = FSPRG_GetEpoch(f->fsprg_state); | |
154 | if (epoch < goal) | |
14228c0d | 155 | log_debug("Evolving FSPRG key from epoch %"PRIu64" to %"PRIu64".", epoch, goal); |
663996b3 MS |
156 | |
157 | for (;;) { | |
158 | if (epoch > goal) | |
159 | return -ESTALE; | |
160 | if (epoch == goal) | |
161 | return 0; | |
162 | ||
163 | FSPRG_Evolve(f->fsprg_state); | |
164 | epoch = FSPRG_GetEpoch(f->fsprg_state); | |
165 | } | |
166 | } | |
167 | ||
168 | int journal_file_fsprg_seek(JournalFile *f, uint64_t goal) { | |
169 | void *msk; | |
170 | uint64_t epoch; | |
171 | ||
172 | assert(f); | |
173 | ||
174 | if (!f->seal) | |
175 | return 0; | |
176 | ||
177 | assert(f->fsprg_seed); | |
178 | ||
179 | if (f->fsprg_state) { | |
180 | /* Cheaper... */ | |
181 | ||
182 | epoch = FSPRG_GetEpoch(f->fsprg_state); | |
183 | if (goal == epoch) | |
184 | return 0; | |
185 | ||
186 | if (goal == epoch+1) { | |
187 | FSPRG_Evolve(f->fsprg_state); | |
188 | return 0; | |
189 | } | |
190 | } else { | |
191 | f->fsprg_state_size = FSPRG_stateinbytes(FSPRG_RECOMMENDED_SECPAR); | |
192 | f->fsprg_state = malloc(f->fsprg_state_size); | |
193 | ||
194 | if (!f->fsprg_state) | |
195 | return -ENOMEM; | |
196 | } | |
197 | ||
14228c0d | 198 | log_debug("Seeking FSPRG key to %"PRIu64".", goal); |
663996b3 MS |
199 | |
200 | msk = alloca(FSPRG_mskinbytes(FSPRG_RECOMMENDED_SECPAR)); | |
201 | FSPRG_GenMK(msk, NULL, f->fsprg_seed, f->fsprg_seed_size, FSPRG_RECOMMENDED_SECPAR); | |
202 | FSPRG_Seek(f->fsprg_state, goal, msk, f->fsprg_seed, f->fsprg_seed_size); | |
203 | return 0; | |
204 | } | |
205 | ||
206 | int journal_file_maybe_append_tag(JournalFile *f, uint64_t realtime) { | |
207 | int r; | |
208 | ||
209 | assert(f); | |
210 | ||
211 | if (!f->seal) | |
212 | return 0; | |
213 | ||
214 | if (realtime <= 0) | |
215 | realtime = now(CLOCK_REALTIME); | |
216 | ||
217 | r = journal_file_fsprg_need_evolve(f, realtime); | |
218 | if (r <= 0) | |
219 | return 0; | |
220 | ||
221 | r = journal_file_append_tag(f); | |
222 | if (r < 0) | |
223 | return r; | |
224 | ||
225 | r = journal_file_fsprg_evolve(f, realtime); | |
226 | if (r < 0) | |
227 | return r; | |
228 | ||
229 | return 0; | |
230 | } | |
231 | ||
232 | int journal_file_hmac_put_object(JournalFile *f, int type, Object *o, uint64_t p) { | |
233 | int r; | |
234 | ||
235 | assert(f); | |
236 | ||
237 | if (!f->seal) | |
238 | return 0; | |
239 | ||
240 | r = journal_file_hmac_start(f); | |
241 | if (r < 0) | |
242 | return r; | |
243 | ||
244 | if (!o) { | |
245 | r = journal_file_move_to_object(f, type, p, &o); | |
246 | if (r < 0) | |
247 | return r; | |
248 | } else { | |
249 | if (type >= 0 && o->object.type != type) | |
250 | return -EBADMSG; | |
251 | } | |
252 | ||
253 | gcry_md_write(f->hmac, o, offsetof(ObjectHeader, payload)); | |
254 | ||
255 | switch (o->object.type) { | |
256 | ||
257 | case OBJECT_DATA: | |
258 | /* All but hash and payload are mutable */ | |
259 | gcry_md_write(f->hmac, &o->data.hash, sizeof(o->data.hash)); | |
260 | gcry_md_write(f->hmac, o->data.payload, le64toh(o->object.size) - offsetof(DataObject, payload)); | |
261 | break; | |
262 | ||
263 | case OBJECT_FIELD: | |
264 | /* Same here */ | |
265 | gcry_md_write(f->hmac, &o->field.hash, sizeof(o->field.hash)); | |
266 | gcry_md_write(f->hmac, o->field.payload, le64toh(o->object.size) - offsetof(FieldObject, payload)); | |
267 | break; | |
268 | ||
269 | case OBJECT_ENTRY: | |
270 | /* All */ | |
271 | gcry_md_write(f->hmac, &o->entry.seqnum, le64toh(o->object.size) - offsetof(EntryObject, seqnum)); | |
272 | break; | |
273 | ||
274 | case OBJECT_FIELD_HASH_TABLE: | |
275 | case OBJECT_DATA_HASH_TABLE: | |
276 | case OBJECT_ENTRY_ARRAY: | |
277 | /* Nothing: everything is mutable */ | |
278 | break; | |
279 | ||
280 | case OBJECT_TAG: | |
281 | /* All but the tag itself */ | |
282 | gcry_md_write(f->hmac, &o->tag.seqnum, sizeof(o->tag.seqnum)); | |
283 | gcry_md_write(f->hmac, &o->tag.epoch, sizeof(o->tag.epoch)); | |
284 | break; | |
285 | default: | |
286 | return -EINVAL; | |
287 | } | |
288 | ||
289 | return 0; | |
290 | } | |
291 | ||
292 | int journal_file_hmac_put_header(JournalFile *f) { | |
293 | int r; | |
294 | ||
295 | assert(f); | |
296 | ||
297 | if (!f->seal) | |
298 | return 0; | |
299 | ||
300 | r = journal_file_hmac_start(f); | |
301 | if (r < 0) | |
302 | return r; | |
303 | ||
304 | /* All but state+reserved, boot_id, arena_size, | |
305 | * tail_object_offset, n_objects, n_entries, | |
306 | * tail_entry_seqnum, head_entry_seqnum, entry_array_offset, | |
307 | * head_entry_realtime, tail_entry_realtime, | |
308 | * tail_entry_monotonic, n_data, n_fields, n_tags, | |
309 | * n_entry_arrays. */ | |
310 | ||
311 | gcry_md_write(f->hmac, f->header->signature, offsetof(Header, state) - offsetof(Header, signature)); | |
312 | gcry_md_write(f->hmac, &f->header->file_id, offsetof(Header, boot_id) - offsetof(Header, file_id)); | |
313 | gcry_md_write(f->hmac, &f->header->seqnum_id, offsetof(Header, arena_size) - offsetof(Header, seqnum_id)); | |
314 | gcry_md_write(f->hmac, &f->header->data_hash_table_offset, offsetof(Header, tail_object_offset) - offsetof(Header, data_hash_table_offset)); | |
315 | ||
316 | return 0; | |
317 | } | |
318 | ||
319 | int journal_file_fss_load(JournalFile *f) { | |
320 | int r, fd = -1; | |
321 | char *p = NULL; | |
322 | struct stat st; | |
323 | FSSHeader *m = NULL; | |
324 | sd_id128_t machine; | |
325 | ||
326 | assert(f); | |
327 | ||
328 | if (!f->seal) | |
329 | return 0; | |
330 | ||
331 | r = sd_id128_get_machine(&machine); | |
332 | if (r < 0) | |
333 | return r; | |
334 | ||
335 | if (asprintf(&p, "/var/log/journal/" SD_ID128_FORMAT_STR "/fss", | |
336 | SD_ID128_FORMAT_VAL(machine)) < 0) | |
337 | return -ENOMEM; | |
338 | ||
339 | fd = open(p, O_RDWR|O_CLOEXEC|O_NOCTTY, 0600); | |
340 | if (fd < 0) { | |
341 | if (errno != ENOENT) | |
f47781d8 | 342 | log_error_errno(errno, "Failed to open %s: %m", p); |
663996b3 MS |
343 | |
344 | r = -errno; | |
345 | goto finish; | |
346 | } | |
347 | ||
348 | if (fstat(fd, &st) < 0) { | |
349 | r = -errno; | |
350 | goto finish; | |
351 | } | |
352 | ||
353 | if (st.st_size < (off_t) sizeof(FSSHeader)) { | |
354 | r = -ENODATA; | |
355 | goto finish; | |
356 | } | |
357 | ||
358 | m = mmap(NULL, PAGE_ALIGN(sizeof(FSSHeader)), PROT_READ, MAP_SHARED, fd, 0); | |
359 | if (m == MAP_FAILED) { | |
360 | m = NULL; | |
361 | r = -errno; | |
362 | goto finish; | |
363 | } | |
364 | ||
365 | if (memcmp(m->signature, FSS_HEADER_SIGNATURE, 8) != 0) { | |
366 | r = -EBADMSG; | |
367 | goto finish; | |
368 | } | |
369 | ||
370 | if (m->incompatible_flags != 0) { | |
371 | r = -EPROTONOSUPPORT; | |
372 | goto finish; | |
373 | } | |
374 | ||
375 | if (le64toh(m->header_size) < sizeof(FSSHeader)) { | |
376 | r = -EBADMSG; | |
377 | goto finish; | |
378 | } | |
379 | ||
380 | if (le64toh(m->fsprg_state_size) != FSPRG_stateinbytes(le16toh(m->fsprg_secpar))) { | |
381 | r = -EBADMSG; | |
382 | goto finish; | |
383 | } | |
384 | ||
385 | f->fss_file_size = le64toh(m->header_size) + le64toh(m->fsprg_state_size); | |
386 | if ((uint64_t) st.st_size < f->fss_file_size) { | |
387 | r = -ENODATA; | |
388 | goto finish; | |
389 | } | |
390 | ||
391 | if (!sd_id128_equal(machine, m->machine_id)) { | |
392 | r = -EHOSTDOWN; | |
393 | goto finish; | |
394 | } | |
395 | ||
396 | if (le64toh(m->start_usec) <= 0 || | |
397 | le64toh(m->interval_usec) <= 0) { | |
398 | r = -EBADMSG; | |
399 | goto finish; | |
400 | } | |
401 | ||
402 | f->fss_file = mmap(NULL, PAGE_ALIGN(f->fss_file_size), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); | |
403 | if (f->fss_file == MAP_FAILED) { | |
404 | f->fss_file = NULL; | |
405 | r = -errno; | |
406 | goto finish; | |
407 | } | |
408 | ||
409 | f->fss_start_usec = le64toh(f->fss_file->start_usec); | |
410 | f->fss_interval_usec = le64toh(f->fss_file->interval_usec); | |
411 | ||
412 | f->fsprg_state = (uint8_t*) f->fss_file + le64toh(f->fss_file->header_size); | |
413 | f->fsprg_state_size = le64toh(f->fss_file->fsprg_state_size); | |
414 | ||
415 | r = 0; | |
416 | ||
417 | finish: | |
418 | if (m) | |
419 | munmap(m, PAGE_ALIGN(sizeof(FSSHeader))); | |
420 | ||
60f067b4 | 421 | safe_close(fd); |
663996b3 | 422 | free(p); |
60f067b4 | 423 | |
663996b3 MS |
424 | return r; |
425 | } | |
426 | ||
427 | static void initialize_libgcrypt(void) { | |
428 | const char *p; | |
429 | ||
430 | if (gcry_control(GCRYCTL_INITIALIZATION_FINISHED_P)) | |
431 | return; | |
432 | ||
433 | p = gcry_check_version("1.4.5"); | |
434 | assert(p); | |
435 | ||
436 | gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0); | |
437 | } | |
438 | ||
439 | int journal_file_hmac_setup(JournalFile *f) { | |
440 | gcry_error_t e; | |
441 | ||
442 | if (!f->seal) | |
443 | return 0; | |
444 | ||
445 | initialize_libgcrypt(); | |
446 | ||
447 | e = gcry_md_open(&f->hmac, GCRY_MD_SHA256, GCRY_MD_FLAG_HMAC); | |
448 | if (e != 0) | |
449 | return -ENOTSUP; | |
450 | ||
451 | return 0; | |
452 | } | |
453 | ||
454 | int journal_file_append_first_tag(JournalFile *f) { | |
455 | int r; | |
456 | uint64_t p; | |
457 | ||
458 | if (!f->seal) | |
459 | return 0; | |
460 | ||
461 | log_debug("Calculating first tag..."); | |
462 | ||
463 | r = journal_file_hmac_put_header(f); | |
464 | if (r < 0) | |
465 | return r; | |
466 | ||
467 | p = le64toh(f->header->field_hash_table_offset); | |
468 | if (p < offsetof(Object, hash_table.items)) | |
469 | return -EINVAL; | |
470 | p -= offsetof(Object, hash_table.items); | |
471 | ||
472 | r = journal_file_hmac_put_object(f, OBJECT_FIELD_HASH_TABLE, NULL, p); | |
473 | if (r < 0) | |
474 | return r; | |
475 | ||
476 | p = le64toh(f->header->data_hash_table_offset); | |
477 | if (p < offsetof(Object, hash_table.items)) | |
478 | return -EINVAL; | |
479 | p -= offsetof(Object, hash_table.items); | |
480 | ||
481 | r = journal_file_hmac_put_object(f, OBJECT_DATA_HASH_TABLE, NULL, p); | |
482 | if (r < 0) | |
483 | return r; | |
484 | ||
485 | r = journal_file_append_tag(f); | |
486 | if (r < 0) | |
487 | return r; | |
488 | ||
489 | return 0; | |
490 | } | |
491 | ||
492 | int journal_file_parse_verification_key(JournalFile *f, const char *key) { | |
493 | uint8_t *seed; | |
494 | size_t seed_size, c; | |
495 | const char *k; | |
496 | int r; | |
497 | unsigned long long start, interval; | |
498 | ||
499 | seed_size = FSPRG_RECOMMENDED_SEEDLEN; | |
500 | seed = malloc(seed_size); | |
501 | if (!seed) | |
502 | return -ENOMEM; | |
503 | ||
504 | k = key; | |
505 | for (c = 0; c < seed_size; c++) { | |
506 | int x, y; | |
507 | ||
508 | while (*k == '-') | |
509 | k++; | |
510 | ||
511 | x = unhexchar(*k); | |
512 | if (x < 0) { | |
513 | free(seed); | |
514 | return -EINVAL; | |
515 | } | |
516 | k++; | |
517 | y = unhexchar(*k); | |
518 | if (y < 0) { | |
519 | free(seed); | |
520 | return -EINVAL; | |
521 | } | |
522 | k++; | |
523 | ||
524 | seed[c] = (uint8_t) (x * 16 + y); | |
525 | } | |
526 | ||
527 | if (*k != '/') { | |
528 | free(seed); | |
529 | return -EINVAL; | |
530 | } | |
531 | k++; | |
532 | ||
533 | r = sscanf(k, "%llx-%llx", &start, &interval); | |
534 | if (r != 2) { | |
535 | free(seed); | |
536 | return -EINVAL; | |
537 | } | |
538 | ||
539 | f->fsprg_seed = seed; | |
540 | f->fsprg_seed_size = seed_size; | |
541 | ||
542 | f->fss_start_usec = start * interval; | |
543 | f->fss_interval_usec = interval; | |
544 | ||
545 | return 0; | |
546 | } | |
547 | ||
548 | bool journal_file_next_evolve_usec(JournalFile *f, usec_t *u) { | |
549 | uint64_t epoch; | |
550 | ||
551 | assert(f); | |
552 | assert(u); | |
553 | ||
554 | if (!f->seal) | |
555 | return false; | |
556 | ||
557 | epoch = FSPRG_GetEpoch(f->fsprg_state); | |
558 | ||
559 | *u = (usec_t) (f->fss_start_usec + f->fss_interval_usec * epoch + f->fss_interval_usec); | |
560 | ||
561 | return true; | |
562 | } |