/*
* LUKS - Linux Unified Key Setup v2, digest handling
*
* Copyright (C) 2015-2020 Red Hat, Inc. All rights reserved.
* Copyright (C) 2015-2020 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
};
static 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_by_digest(struct crypt_device *cd,
struct luks2_hdr *hdr,
int digest,
const struct volume_key *vk)
{
const digest_handler *h;
int r;
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_verify(struct crypt_device *cd,
struct luks2_hdr *hdr,
const struct volume_key *vk,
int keyslot)
{
int digest;
digest = LUKS2_digest_by_keyslot(hdr, keyslot);
if (digest < 0)
return digest;
log_dbg(cd, "Verifying key from keyslot %d, digest %d.", keyslot, digest);
return LUKS2_digest_verify_by_digest(cd, hdr, digest, vk);
}
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_any_matching(struct crypt_device *cd,
struct luks2_hdr *hdr,
const struct volume_key *vk)
{
int digest;
for (digest = 0; digest < LUKS2_DIGEST_MAX; digest++)
if (LUKS2_digest_verify_by_digest(cd, hdr, digest, vk) == digest)
return digest;
return -ENOENT;
}
int LUKS2_digest_verify_by_segment(struct crypt_device *cd,
struct luks2_hdr *hdr,
int segment,
const struct volume_key *vk)
{
return LUKS2_digest_verify_by_digest(cd, hdr, LUKS2_digest_by_segment(hdr, segment), vk);
}
/* 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;
if (segment == CRYPT_DEFAULT_SEGMENT)
segment = LUKS2_get_default_segment(hdr);
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_all_segments(struct crypt_device *cd, struct luks2_hdr *hdr,
int digest, int assign)
{
json_object *jobj1, *jobj_digest, *jobj_digest_segments;
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;
if (assign) {
json_object_object_foreach(LUKS2_get_segments_jobj(hdr), key, value) {
UNUSED(value);
jobj1 = LUKS2_array_jobj(jobj_digest_segments, key);
if (!jobj1)
json_object_array_add(jobj_digest_segments, json_object_new_string(key));
}
} else {
jobj1 = json_object_new_array();
if (!jobj1)
return -ENOMEM;
json_object_object_add(jobj_digest, "segments", jobj1);
}
return 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 (segment == CRYPT_DEFAULT_SEGMENT)
segment = LUKS2_get_default_segment(hdr);
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);
if (segment == CRYPT_ANY_SEGMENT)
r = assign_all_segments(cd, hdr, atoi(key), assign);
else
r = assign_one_segment(cd, hdr, segment, atoi(key), assign);
if (r < 0)
break;
}
} else {
if (segment == CRYPT_ANY_SEGMENT)
r = assign_all_segments(cd, hdr, digest, assign);
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;
}
int LUKS2_volume_key_load_in_keyring_by_digest(struct crypt_device *cd,
struct luks2_hdr *hdr, struct volume_key *vk, int digest)
{
char *desc = get_key_description_by_digest(cd, digest);
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;
}