1 files changed, 455 insertions, 0 deletions
diff --git a/lib/luks2/luks2_digest.c b/lib/luks2/luks2_digest.c
new file mode 100644
index 0000000..933b059
--- /dev/null
+++ b/lib/luks2/luks2_digest.c
@@ -0,0 +1,455 @@
+/*
+ * LUKS - Linux Unified Key Setup v2, digest handling
+ *
+ * Copyright (C) 2015-2023 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2015-2023 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(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(json_object_get_string(jobj2));
+}
+
+static int LUKS2_digest_find_free(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(type);
+	if (!dh)
+		return -EINVAL;
+
+	digest = LUKS2_digest_find_free(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,
+	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, 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, 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, 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;
+
+	if (snprintf(num, sizeof(num), "%d", keyslot) < 0)
+		return -EINVAL;
+
+	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;
+
+	return commit ? LUKS2_hdr_write(cd, hdr) : 0;
+}
+
+static int assign_all_segments(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;
+
+	if (snprintf(num, sizeof(num), "%d", segment) < 0)
+		return -EINVAL;
+
+	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(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(hdr, digest, assign);
+		else
+			r = assign_one_segment(cd, hdr, segment, digest, assign);
+	}
+
+	if (r < 0)
+		return r;
+
+	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 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;
+}