-static void *fsprg_state(JournalFile *f) {
- uint64_t a, b;
- assert(f);
-
- if (!f->authenticate)
- return NULL;
-
- a = le64toh(f->fsprg_header->header_size);
- b = le64toh(f->fsprg_header->state_size);
-
- if (a + b > f->fsprg_size)
- return NULL;
-
- return (uint8_t*) f->fsprg_header + a;
-}
-
-static uint64_t journal_file_tag_seqnum(JournalFile *f) {
- uint64_t r;
-
- assert(f);
-
- r = le64toh(f->header->n_tags) + 1;
- f->header->n_tags = htole64(r);
-
- return r;
-}
-
-int journal_file_append_tag(JournalFile *f) {
- Object *o;
- uint64_t p;
- int r;
-
- assert(f);
-
- if (!f->authenticate)
- return 0;
-
- if (!f->hmac_running)
- return 0;
-
- log_debug("Writing tag for epoch %llu\n", (unsigned long long) FSPRG_GetEpoch(fsprg_state(f)));
-
- assert(f->hmac);
-
- r = journal_file_append_object(f, OBJECT_TAG, sizeof(struct TagObject), &o, &p);
- if (r < 0)
- return r;
-
- o->tag.seqnum = htole64(journal_file_tag_seqnum(f));
-
- /* Add the tag object itself, so that we can protect its
- * header. This will exclude the actual hash value in it */
- r = journal_file_hmac_put_object(f, OBJECT_TAG, p);
- if (r < 0)
- return r;
-
- /* Get the HMAC tag and store it in the object */
- memcpy(o->tag.tag, gcry_md_read(f->hmac, 0), TAG_LENGTH);
- f->hmac_running = false;
-
- return 0;
-}
-
-static int journal_file_hmac_start(JournalFile *f) {
- uint8_t key[256 / 8]; /* Let's pass 256 bit from FSPRG to HMAC */
-
- assert(f);
-
- if (!f->authenticate)
- return 0;
-
- if (f->hmac_running)
- return 0;
-
- /* Prepare HMAC for next cycle */
- gcry_md_reset(f->hmac);
- FSPRG_GetKey(fsprg_state(f), key, sizeof(key), 0);
- gcry_md_setkey(f->hmac, key, sizeof(key));
-
- f->hmac_running = true;
-
- return 0;
-}
-
-static int journal_file_get_epoch(JournalFile *f, uint64_t realtime, uint64_t *epoch) {
- uint64_t t;
-
- assert(f);
- assert(epoch);
- assert(f->authenticate);
-
- if (le64toh(f->fsprg_header->fsprg_start_usec) == 0 ||
- le64toh(f->fsprg_header->fsprg_interval_usec) == 0)
- return -ENOTSUP;
-
- if (realtime < le64toh(f->fsprg_header->fsprg_start_usec))
- return -ESTALE;
-
- t = realtime - le64toh(f->fsprg_header->fsprg_start_usec);
- t = t / le64toh(f->fsprg_header->fsprg_interval_usec);
-
- *epoch = t;
- return 0;
-}
-
-static int journal_file_need_evolve(JournalFile *f, uint64_t realtime) {
- uint64_t goal, epoch;
- int r;
- assert(f);
-
- if (!f->authenticate)
- return 0;
-
- r = journal_file_get_epoch(f, realtime, &goal);
- if (r < 0)
- return r;
-
- epoch = FSPRG_GetEpoch(fsprg_state(f));
- if (epoch > goal)
- return -ESTALE;
-
- return epoch != goal;
-}
-
-static int journal_file_evolve(JournalFile *f, uint64_t realtime) {
- uint64_t goal, epoch;
- int r;
-
- assert(f);
-
- if (!f->authenticate)
- return 0;
-
- r = journal_file_get_epoch(f, realtime, &goal);
- if (r < 0)
- return r;
-
- epoch = FSPRG_GetEpoch(fsprg_state(f));
- if (epoch < goal)
- log_debug("Evolving FSPRG key from epoch %llu to %llu.", (unsigned long long) epoch, (unsigned long long) goal);
-
- for (;;) {
- if (epoch > goal)
- return -ESTALE;
- if (epoch == goal)
- return 0;
-
- FSPRG_Evolve(fsprg_state(f));
- epoch = FSPRG_GetEpoch(fsprg_state(f));
- }
-}
-
-static int journal_file_maybe_append_tag(JournalFile *f, uint64_t realtime) {
- int r;
-
- assert(f);
-
- if (!f->authenticate)
- return 0;
-
- r = journal_file_need_evolve(f, realtime);
- if (r <= 0)
- return 0;
-
- r = journal_file_append_tag(f);
- if (r < 0)
- return r;
-
- r = journal_file_evolve(f, realtime);
- if (r < 0)
- return r;
-
- r = journal_file_hmac_start(f);
- if (r < 0)
- return r;
-
- return 0;
-}
-
-static int journal_file_hmac_put_object(JournalFile *f, int type, uint64_t p) {
- int r;
- Object *o;
-
- assert(f);
-
- if (!f->authenticate)
- return 0;
-
- r = journal_file_hmac_start(f);
- if (r < 0)
- return r;
-
- r = journal_file_move_to_object(f, type, p, &o);
- if (r < 0)
- return r;
-
- gcry_md_write(f->hmac, o, offsetof(ObjectHeader, payload));
-
- switch (o->object.type) {
-
- case OBJECT_DATA:
- /* All but: hash and payload are mutable */
- gcry_md_write(f->hmac, &o->data.hash, sizeof(o->data.hash));
- gcry_md_write(f->hmac, o->data.payload, le64toh(o->object.size) - offsetof(DataObject, payload));
- break;
-
- case OBJECT_ENTRY:
- /* All */
- gcry_md_write(f->hmac, &o->entry.seqnum, le64toh(o->object.size) - offsetof(EntryObject, seqnum));
- break;
-
- case OBJECT_FIELD_HASH_TABLE:
- case OBJECT_DATA_HASH_TABLE:
- case OBJECT_ENTRY_ARRAY:
- /* Nothing: everything is mutable */
- break;
-
- case OBJECT_TAG:
- /* All but the tag itself */
- gcry_md_write(f->hmac, &o->tag.seqnum, sizeof(o->tag.seqnum));
- break;
- default:
- return -EINVAL;
- }
-
- return 0;
-}
-
-static int journal_file_hmac_put_header(JournalFile *f) {
- int r;
-
- assert(f);
-
- if (!f->authenticate)
- return 0;
-
- r = journal_file_hmac_start(f);
- if (r < 0)
- return r;
-
- /* All but state+reserved, boot_id, arena_size,
- * tail_object_offset, n_objects, n_entries, tail_seqnum,
- * head_entry_realtime, tail_entry_realtime,
- * tail_entry_monotonic, n_data, n_fields, header_tag */
-
- gcry_md_write(f->hmac, f->header->signature, offsetof(Header, state) - offsetof(Header, signature));
- gcry_md_write(f->hmac, &f->header->file_id, offsetof(Header, boot_id) - offsetof(Header, file_id));
- gcry_md_write(f->hmac, &f->header->seqnum_id, offsetof(Header, arena_size) - offsetof(Header, seqnum_id));
- gcry_md_write(f->hmac, &f->header->data_hash_table_offset, offsetof(Header, tail_object_offset) - offsetof(Header, data_hash_table_offset));
- gcry_md_write(f->hmac, &f->header->head_seqnum, offsetof(Header, head_entry_realtime) - offsetof(Header, head_seqnum));
-
- return 0;
-}
-
-static int journal_file_load_fsprg(JournalFile *f) {
- int r, fd = -1;
- char *p = NULL;
- struct stat st;
- FSPRGHeader *m = NULL;
- sd_id128_t machine;
-
- assert(f);
-
- if (!f->authenticate)
- return 0;
-
- r = sd_id128_get_machine(&machine);
- if (r < 0)
- return r;
-
- if (asprintf(&p, "/var/log/journal/" SD_ID128_FORMAT_STR "/fsprg",
- SD_ID128_FORMAT_VAL(machine)) < 0)
- return -ENOMEM;
-
- fd = open(p, O_RDWR|O_CLOEXEC|O_NOCTTY, 0600);
- if (fd < 0) {
- log_error("Failed to open %s: %m", p);
- r = -errno;
- goto finish;
- }
-
- if (fstat(fd, &st) < 0) {
- r = -errno;
- goto finish;
- }
-
- if (st.st_size < (off_t) sizeof(FSPRGHeader)) {
- r = -ENODATA;
- goto finish;
- }
-
- m = mmap(NULL, PAGE_ALIGN(sizeof(FSPRGHeader)), PROT_READ, MAP_SHARED, fd, 0);
- if (m == MAP_FAILED) {
- m = NULL;
- r = -errno;
- goto finish;
- }
-
- if (memcmp(m->signature, FSPRG_HEADER_SIGNATURE, 8) != 0) {
- r = -EBADMSG;
- goto finish;
- }
-
- if (m->incompatible_flags != 0) {
- r = -EPROTONOSUPPORT;
- goto finish;
- }
-
- if (le64toh(m->header_size) < sizeof(FSPRGHeader)) {
- r = -EBADMSG;
- goto finish;
- }
-
- if (le64toh(m->state_size) != FSPRG_stateinbytes(m->secpar)) {
- r = -EBADMSG;
- goto finish;
- }
-
- f->fsprg_size = le64toh(m->header_size) + le64toh(m->state_size);
- if ((uint64_t) st.st_size < f->fsprg_size) {
- r = -ENODATA;
- goto finish;
- }
-
- if (!sd_id128_equal(machine, m->machine_id)) {
- r = -EHOSTDOWN;
- goto finish;
- }
-
- if (le64toh(m->fsprg_start_usec) <= 0 ||
- le64toh(m->fsprg_interval_usec) <= 0) {
- r = -EBADMSG;
- goto finish;
- }
-
- f->fsprg_header = mmap(NULL, PAGE_ALIGN(f->fsprg_size), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
- if (f->fsprg_header == MAP_FAILED) {
- f->fsprg_header = NULL;
- r = -errno;
- goto finish;
- }
-
- r = 0;
-
-finish:
- if (m)
- munmap(m, PAGE_ALIGN(sizeof(FSPRGHeader)));
-
- if (fd >= 0)
- close_nointr_nofail(fd);
-
- free(p);
- return r;
-}
-
-static int journal_file_setup_hmac(JournalFile *f) {
- gcry_error_t e;
-
- if (!f->authenticate)
- return 0;
-
- e = gcry_md_open(&f->hmac, GCRY_MD_SHA256, GCRY_MD_FLAG_HMAC);
- if (e != 0)
- return -ENOTSUP;
-
- return 0;
-}
-
-static int journal_file_append_first_tag(JournalFile *f) {
- int r;
- uint64_t p;
-
- if (!f->authenticate)
- return 0;
-
- log_debug("Calculating first tag...");
-
- r = journal_file_hmac_put_header(f);
- if (r < 0)
- return r;
-
- p = le64toh(f->header->field_hash_table_offset);
- if (p < offsetof(Object, hash_table.items))
- return -EINVAL;
- p -= offsetof(Object, hash_table.items);
-
- r = journal_file_hmac_put_object(f, OBJECT_FIELD_HASH_TABLE, p);
- if (r < 0)
- return r;
-
- p = le64toh(f->header->data_hash_table_offset);
- if (p < offsetof(Object, hash_table.items))
- return -EINVAL;
- p -= offsetof(Object, hash_table.items);
-
- r = journal_file_hmac_put_object(f, OBJECT_DATA_HASH_TABLE, p);
- if (r < 0)
- return r;
-
- r = journal_file_append_tag(f);
- if (r < 0)
- return r;
-
- return 0;
-}
-