/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2012 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 <fcntl.h> #include <sys/mman.h> #include "journal-def.h" #include "journal-file.h" #include "journal-authenticate.h" #include "fsprg.h" 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->seal) return 0; if (!f->hmac_running) return 0; 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)); o->tag.epoch = htole64(FSPRG_GetEpoch(f->fsprg_state)); log_debug("Writing tag %"PRIu64" for epoch %"PRIu64"\n", le64toh(o->tag.seqnum), FSPRG_GetEpoch(f->fsprg_state)); /* 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, o, 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; } 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->seal) return 0; if (f->hmac_running) return 0; /* Prepare HMAC for next cycle */ gcry_md_reset(f->hmac); FSPRG_GetKey(f->fsprg_state, 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->seal); if (f->fss_start_usec == 0 || f->fss_interval_usec == 0) return -ENOTSUP; if (realtime < f->fss_start_usec) return -ESTALE; t = realtime - f->fss_start_usec; t = t / f->fss_interval_usec; *epoch = t; return 0; } static int journal_file_fsprg_need_evolve(JournalFile *f, uint64_t realtime) { uint64_t goal, epoch; int r; assert(f); if (!f->seal) return 0; r = journal_file_get_epoch(f, realtime, &goal); if (r < 0) return r; epoch = FSPRG_GetEpoch(f->fsprg_state); if (epoch > goal) return -ESTALE; return epoch != goal; } int journal_file_fsprg_evolve(JournalFile *f, uint64_t realtime) { uint64_t goal, epoch; int r; assert(f); if (!f->seal) return 0; r = journal_file_get_epoch(f, realtime, &goal); if (r < 0) return r; epoch = FSPRG_GetEpoch(f->fsprg_state); if (epoch < goal) log_debug("Evolving FSPRG key from epoch %"PRIu64" to %"PRIu64".", epoch, goal); for (;;) { if (epoch > goal) return -ESTALE; if (epoch == goal) return 0; FSPRG_Evolve(f->fsprg_state); epoch = FSPRG_GetEpoch(f->fsprg_state); } } int journal_file_fsprg_seek(JournalFile *f, uint64_t goal) { void *msk; uint64_t epoch; assert(f); if (!f->seal) return 0; assert(f->fsprg_seed); if (f->fsprg_state) { /* Cheaper... */ epoch = FSPRG_GetEpoch(f->fsprg_state); if (goal == epoch) return 0; if (goal == epoch+1) { FSPRG_Evolve(f->fsprg_state); return 0; } } else { f->fsprg_state_size = FSPRG_stateinbytes(FSPRG_RECOMMENDED_SECPAR); f->fsprg_state = malloc(f->fsprg_state_size); if (!f->fsprg_state) return -ENOMEM; } log_debug("Seeking FSPRG key to %"PRIu64".", goal); msk = alloca(FSPRG_mskinbytes(FSPRG_RECOMMENDED_SECPAR)); FSPRG_GenMK(msk, NULL, f->fsprg_seed, f->fsprg_seed_size, FSPRG_RECOMMENDED_SECPAR); FSPRG_Seek(f->fsprg_state, goal, msk, f->fsprg_seed, f->fsprg_seed_size); return 0; } int journal_file_maybe_append_tag(JournalFile *f, uint64_t realtime) { int r; assert(f); if (!f->seal) return 0; if (realtime <= 0) realtime = now(CLOCK_REALTIME); r = journal_file_fsprg_need_evolve(f, realtime); if (r <= 0) return 0; r = journal_file_append_tag(f); if (r < 0) return r; r = journal_file_fsprg_evolve(f, realtime); if (r < 0) return r; return 0; } int journal_file_hmac_put_object(JournalFile *f, int type, Object *o, uint64_t p) { int r; assert(f); if (!f->seal) return 0; r = journal_file_hmac_start(f); if (r < 0) return r; if (!o) { r = journal_file_move_to_object(f, type, p, &o); if (r < 0) return r; } else { if (type >= 0 && o->object.type != type) return -EBADMSG; } 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_FIELD: /* Same here */ gcry_md_write(f->hmac, &o->field.hash, sizeof(o->field.hash)); gcry_md_write(f->hmac, o->field.payload, le64toh(o->object.size) - offsetof(FieldObject, 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)); gcry_md_write(f->hmac, &o->tag.epoch, sizeof(o->tag.epoch)); break; default: return -EINVAL; } return 0; } int journal_file_hmac_put_header(JournalFile *f) { int r; assert(f); if (!f->seal) 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_entry_seqnum, head_entry_seqnum, entry_array_offset, * head_entry_realtime, tail_entry_realtime, * tail_entry_monotonic, n_data, n_fields, n_tags, * n_entry_arrays. */ 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)); return 0; } int journal_file_fss_load(JournalFile *f) { int r, fd = -1; char *p = NULL; struct stat st; FSSHeader *m = NULL; sd_id128_t machine; assert(f); if (!f->seal) return 0; r = sd_id128_get_machine(&machine); if (r < 0) return r; if (asprintf(&p, "/var/log/journal/" SD_ID128_FORMAT_STR "/fss", SD_ID128_FORMAT_VAL(machine)) < 0) return -ENOMEM; fd = open(p, O_RDWR|O_CLOEXEC|O_NOCTTY, 0600); if (fd < 0) { if (errno != ENOENT) 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(FSSHeader)) { r = -ENODATA; goto finish; } m = mmap(NULL, PAGE_ALIGN(sizeof(FSSHeader)), PROT_READ, MAP_SHARED, fd, 0); if (m == MAP_FAILED) { m = NULL; r = -errno; goto finish; } if (memcmp(m->signature, FSS_HEADER_SIGNATURE, 8) != 0) { r = -EBADMSG; goto finish; } if (m->incompatible_flags != 0) { r = -EPROTONOSUPPORT; goto finish; } if (le64toh(m->header_size) < sizeof(FSSHeader)) { r = -EBADMSG; goto finish; } if (le64toh(m->fsprg_state_size) != FSPRG_stateinbytes(le16toh(m->fsprg_secpar))) { r = -EBADMSG; goto finish; } f->fss_file_size = le64toh(m->header_size) + le64toh(m->fsprg_state_size); if ((uint64_t) st.st_size < f->fss_file_size) { r = -ENODATA; goto finish; } if (!sd_id128_equal(machine, m->machine_id)) { r = -EHOSTDOWN; goto finish; } if (le64toh(m->start_usec) <= 0 || le64toh(m->interval_usec) <= 0) { r = -EBADMSG; goto finish; } f->fss_file = mmap(NULL, PAGE_ALIGN(f->fss_file_size), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); if (f->fss_file == MAP_FAILED) { f->fss_file = NULL; r = -errno; goto finish; } f->fss_start_usec = le64toh(f->fss_file->start_usec); f->fss_interval_usec = le64toh(f->fss_file->interval_usec); f->fsprg_state = (uint8_t*) f->fss_file + le64toh(f->fss_file->header_size); f->fsprg_state_size = le64toh(f->fss_file->fsprg_state_size); r = 0; finish: if (m) munmap(m, PAGE_ALIGN(sizeof(FSSHeader))); if (fd >= 0) close_nointr_nofail(fd); free(p); return r; } static void initialize_libgcrypt(void) { const char *p; if (gcry_control(GCRYCTL_INITIALIZATION_FINISHED_P)) return; p = gcry_check_version("1.4.5"); assert(p); gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0); } int journal_file_hmac_setup(JournalFile *f) { gcry_error_t e; if (!f->seal) return 0; initialize_libgcrypt(); e = gcry_md_open(&f->hmac, GCRY_MD_SHA256, GCRY_MD_FLAG_HMAC); if (e != 0) return -ENOTSUP; return 0; } int journal_file_append_first_tag(JournalFile *f) { int r; uint64_t p; if (!f->seal) 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, NULL, 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, NULL, p); if (r < 0) return r; r = journal_file_append_tag(f); if (r < 0) return r; return 0; } int journal_file_parse_verification_key(JournalFile *f, const char *key) { uint8_t *seed; size_t seed_size, c; const char *k; int r; unsigned long long start, interval; seed_size = FSPRG_RECOMMENDED_SEEDLEN; seed = malloc(seed_size); if (!seed) return -ENOMEM; k = key; for (c = 0; c < seed_size; c++) { int x, y; while (*k == '-') k++; x = unhexchar(*k); if (x < 0) { free(seed); return -EINVAL; } k++; y = unhexchar(*k); if (y < 0) { free(seed); return -EINVAL; } k++; seed[c] = (uint8_t) (x * 16 + y); } if (*k != '/') { free(seed); return -EINVAL; } k++; r = sscanf(k, "%llx-%llx", &start, &interval); if (r != 2) { free(seed); return -EINVAL; } f->fsprg_seed = seed; f->fsprg_seed_size = seed_size; f->fss_start_usec = start * interval; f->fss_interval_usec = interval; return 0; } bool journal_file_next_evolve_usec(JournalFile *f, usec_t *u) { uint64_t epoch; assert(f); assert(u); if (!f->seal) return false; epoch = FSPRG_GetEpoch(f->fsprg_state); *u = (usec_t) (f->fss_start_usec + f->fss_interval_usec * epoch + f->fss_interval_usec); return true; }