diff options
Diffstat (limited to 'lib/luks2/luks2_digest.c')
| -rw-r--r-- | lib/luks2/luks2_digest.c | 393 |
1 files changed, 393 insertions, 0 deletions
diff --git a/lib/luks2/luks2_digest.c b/lib/luks2/luks2_digest.c new file mode 100644 index 0000000..246903c --- /dev/null +++ b/lib/luks2/luks2_digest.c @@ -0,0 +1,393 @@ +/* + * LUKS - Linux Unified Key Setup v2, digest handling + * + * Copyright (C) 2015-2019 Red Hat, Inc. All rights reserved. + * Copyright (C) 2015-2019 Milan Broz + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "luks2_internal.h" + +extern const digest_handler PBKDF2_digest; + +static const digest_handler *digest_handlers[LUKS2_DIGEST_MAX] = { + &PBKDF2_digest, + NULL +}; + +const digest_handler *LUKS2_digest_handler_type(struct crypt_device *cd, const char *type) +{ + int i; + + for (i = 0; i < LUKS2_DIGEST_MAX && digest_handlers[i]; i++) { + if (!strcmp(digest_handlers[i]->name, type)) + return digest_handlers[i]; + } + + return NULL; +} + +static const digest_handler *LUKS2_digest_handler(struct crypt_device *cd, int digest) +{ + struct luks2_hdr *hdr; + json_object *jobj1, *jobj2; + + if (digest < 0) + return NULL; + + if (!(hdr = crypt_get_hdr(cd, CRYPT_LUKS2))) + return NULL; + + if (!(jobj1 = LUKS2_get_digest_jobj(hdr, digest))) + return NULL; + + if (!json_object_object_get_ex(jobj1, "type", &jobj2)) + return NULL; + + return LUKS2_digest_handler_type(cd, json_object_get_string(jobj2)); +} + +static int LUKS2_digest_find_free(struct crypt_device *cd, struct luks2_hdr *hdr) +{ + int digest = 0; + + while (LUKS2_get_digest_jobj(hdr, digest) && digest < LUKS2_DIGEST_MAX) + digest++; + + return digest < LUKS2_DIGEST_MAX ? digest : -1; +} + +int LUKS2_digest_create(struct crypt_device *cd, + const char *type, + struct luks2_hdr *hdr, + const struct volume_key *vk) +{ + int digest; + const digest_handler *dh; + + dh = LUKS2_digest_handler_type(cd, type); + if (!dh) + return -EINVAL; + + digest = LUKS2_digest_find_free(cd, hdr); + if (digest < 0) + return -EINVAL; + + log_dbg(cd, "Creating new digest %d (%s).", digest, type); + + return dh->store(cd, digest, vk->key, vk->keylength) ?: digest; +} + +int LUKS2_digest_by_keyslot(struct luks2_hdr *hdr, int keyslot) +{ + char keyslot_name[16]; + json_object *jobj_digests, *jobj_digest_keyslots; + + if (snprintf(keyslot_name, sizeof(keyslot_name), "%u", keyslot) < 1) + return -ENOMEM; + + json_object_object_get_ex(hdr->jobj, "digests", &jobj_digests); + + json_object_object_foreach(jobj_digests, key, val) { + json_object_object_get_ex(val, "keyslots", &jobj_digest_keyslots); + if (LUKS2_array_jobj(jobj_digest_keyslots, keyslot_name)) + return atoi(key); + } + + return -ENOENT; +} + +int LUKS2_digest_verify(struct crypt_device *cd, + struct luks2_hdr *hdr, + struct volume_key *vk, + int keyslot) +{ + const digest_handler *h; + int digest, r; + + digest = LUKS2_digest_by_keyslot(hdr, keyslot); + if (digest < 0) + return digest; + + log_dbg(cd, "Verifying key from keyslot %d, digest %d.", keyslot, digest); + h = LUKS2_digest_handler(cd, digest); + if (!h) + return -EINVAL; + + r = h->verify(cd, digest, vk->key, vk->keylength); + if (r < 0) { + log_dbg(cd, "Digest %d (%s) verify failed with %d.", digest, h->name, r); + return r; + } + + return digest; +} + +int LUKS2_digest_dump(struct crypt_device *cd, int digest) +{ + const digest_handler *h; + + if (!(h = LUKS2_digest_handler(cd, digest))) + return -EINVAL; + + return h->dump(cd, digest); +} + +int LUKS2_digest_verify_by_segment(struct crypt_device *cd, + struct luks2_hdr *hdr, + int segment, + const struct volume_key *vk) +{ + const digest_handler *h; + int digest, r; + + digest = LUKS2_digest_by_segment(hdr, segment); + if (digest < 0) + return digest; + + log_dbg(cd, "Verifying key digest %d.", digest); + + h = LUKS2_digest_handler(cd, digest); + if (!h) + return -EINVAL; + + r = h->verify(cd, digest, vk->key, vk->keylength); + if (r < 0) { + log_dbg(cd, "Digest %d (%s) verify failed with %d.", digest, h->name, r); + return r; + } + + return digest; +} + +/* FIXME: segment can have more digests */ +int LUKS2_digest_by_segment(struct luks2_hdr *hdr, int segment) +{ + char segment_name[16]; + json_object *jobj_digests, *jobj_digest_segments; + + json_object_object_get_ex(hdr->jobj, "digests", &jobj_digests); + + if (snprintf(segment_name, sizeof(segment_name), "%u", segment) < 1) + return -EINVAL; + + json_object_object_foreach(jobj_digests, key, val) { + json_object_object_get_ex(val, "segments", &jobj_digest_segments); + if (!LUKS2_array_jobj(jobj_digest_segments, segment_name)) + continue; + + return atoi(key); + } + + return -ENOENT; +} + +static int assign_one_digest(struct crypt_device *cd, struct luks2_hdr *hdr, + int keyslot, int digest, int assign) +{ + json_object *jobj1, *jobj_digest, *jobj_digest_keyslots; + char num[16]; + + log_dbg(cd, "Keyslot %i %s digest %i.", keyslot, assign ? "assigned to" : "unassigned from", digest); + + jobj_digest = LUKS2_get_digest_jobj(hdr, digest); + if (!jobj_digest) + return -EINVAL; + + json_object_object_get_ex(jobj_digest, "keyslots", &jobj_digest_keyslots); + if (!jobj_digest_keyslots) + return -EINVAL; + + snprintf(num, sizeof(num), "%d", keyslot); + if (assign) { + jobj1 = LUKS2_array_jobj(jobj_digest_keyslots, num); + if (!jobj1) + json_object_array_add(jobj_digest_keyslots, json_object_new_string(num)); + } else { + jobj1 = LUKS2_array_remove(jobj_digest_keyslots, num); + if (jobj1) + json_object_object_add(jobj_digest, "keyslots", jobj1); + } + + return 0; +} + +int LUKS2_digest_assign(struct crypt_device *cd, struct luks2_hdr *hdr, + int keyslot, int digest, int assign, int commit) +{ + json_object *jobj_digests; + int r = 0; + + if (digest == CRYPT_ANY_DIGEST) { + json_object_object_get_ex(hdr->jobj, "digests", &jobj_digests); + + json_object_object_foreach(jobj_digests, key, val) { + UNUSED(val); + r = assign_one_digest(cd, hdr, keyslot, atoi(key), assign); + if (r < 0) + break; + } + } else + r = assign_one_digest(cd, hdr, keyslot, digest, assign); + + if (r < 0) + return r; + + // FIXME: do not write header in nothing changed + return commit ? LUKS2_hdr_write(cd, hdr) : 0; +} + +static int assign_one_segment(struct crypt_device *cd, struct luks2_hdr *hdr, + int segment, int digest, int assign) +{ + json_object *jobj1, *jobj_digest, *jobj_digest_segments; + char num[16]; + + log_dbg(cd, "Segment %i %s digest %i.", segment, assign ? "assigned to" : "unassigned from", digest); + + jobj_digest = LUKS2_get_digest_jobj(hdr, digest); + if (!jobj_digest) + return -EINVAL; + + json_object_object_get_ex(jobj_digest, "segments", &jobj_digest_segments); + if (!jobj_digest_segments) + return -EINVAL; + + snprintf(num, sizeof(num), "%d", segment); + if (assign) { + jobj1 = LUKS2_array_jobj(jobj_digest_segments, num); + if (!jobj1) + json_object_array_add(jobj_digest_segments, json_object_new_string(num)); + } else { + jobj1 = LUKS2_array_remove(jobj_digest_segments, num); + if (jobj1) + json_object_object_add(jobj_digest, "segments", jobj1); + } + + return 0; +} + +int LUKS2_digest_segment_assign(struct crypt_device *cd, struct luks2_hdr *hdr, + int segment, int digest, int assign, int commit) +{ + json_object *jobj_digests; + int r = 0; + + if (digest == CRYPT_ANY_DIGEST) { + json_object_object_get_ex(hdr->jobj, "digests", &jobj_digests); + + json_object_object_foreach(jobj_digests, key, val) { + UNUSED(val); + r = assign_one_segment(cd, hdr, segment, atoi(key), assign); + if (r < 0) + break; + } + } else + r = assign_one_segment(cd, hdr, segment, digest, assign); + + if (r < 0) + return r; + + // FIXME: do not write header in nothing changed + return commit ? LUKS2_hdr_write(cd, hdr) : 0; +} + +static int digest_unused(json_object *jobj_digest) +{ + json_object *jobj; + + json_object_object_get_ex(jobj_digest, "segments", &jobj); + if (!jobj || !json_object_is_type(jobj, json_type_array) || json_object_array_length(jobj) > 0) + return 0; + + json_object_object_get_ex(jobj_digest, "keyslots", &jobj); + if (!jobj || !json_object_is_type(jobj, json_type_array)) + return 0; + + return json_object_array_length(jobj) > 0 ? 0 : 1; +} + +void LUKS2_digests_erase_unused(struct crypt_device *cd, + struct luks2_hdr *hdr) +{ + json_object *jobj_digests; + + json_object_object_get_ex(hdr->jobj, "digests", &jobj_digests); + if (!jobj_digests || !json_object_is_type(jobj_digests, json_type_object)) + return; + + json_object_object_foreach(jobj_digests, key, val) { + if (digest_unused(val)) { + log_dbg(cd, "Erasing unused digest %d.", atoi(key)); + json_object_object_del(jobj_digests, key); + } + } +} + +/* Key description helpers */ +static char *get_key_description_by_digest(struct crypt_device *cd, int digest) +{ + char *desc, digest_str[3]; + int r; + size_t len; + + if (!crypt_get_uuid(cd)) + return NULL; + + r = snprintf(digest_str, sizeof(digest_str), "d%u", digest); + if (r < 0 || (size_t)r >= sizeof(digest_str)) + return NULL; + + /* "cryptsetup:<uuid>-<digest_str>" + \0 */ + len = strlen(crypt_get_uuid(cd)) + strlen(digest_str) + 13; + + desc = malloc(len); + if (!desc) + return NULL; + + r = snprintf(desc, len, "%s:%s-%s", "cryptsetup", crypt_get_uuid(cd), digest_str); + if (r < 0 || (size_t)r >= len) { + free(desc); + return NULL; + } + + return desc; +} + +int LUKS2_key_description_by_segment(struct crypt_device *cd, + struct luks2_hdr *hdr, struct volume_key *vk, int segment) +{ + char *desc = get_key_description_by_digest(cd, LUKS2_digest_by_segment(hdr, segment)); + int r; + + r = crypt_volume_key_set_description(vk, desc); + free(desc); + return r; +} + +int LUKS2_volume_key_load_in_keyring_by_keyslot(struct crypt_device *cd, + struct luks2_hdr *hdr, struct volume_key *vk, int keyslot) +{ + char *desc = get_key_description_by_digest(cd, LUKS2_digest_by_keyslot(hdr, keyslot)); + int r; + + r = crypt_volume_key_set_description(vk, desc); + if (!r) + r = crypt_volume_key_load_in_keyring(cd, vk); + + free(desc); + return r; +} |