1 files changed, 408 insertions, 0 deletions
diff --git a/lib/luks2/luks2_json_format.c b/lib/luks2/luks2_json_format.c
new file mode 100644
index 0000000..1540910
--- /dev/null
+++ b/lib/luks2/luks2_json_format.c
@@ -0,0 +1,408 @@
+/*
+ * LUKS - Linux Unified Key Setup v2, LUKS2 header format code
+ *
+ * Copyright (C) 2015-2021 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2015-2021 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"
+#include <uuid/uuid.h>
+#include <assert.h>
+
+struct area {
+	uint64_t offset;
+	uint64_t length;
+};
+
+static size_t get_area_size(size_t keylength)
+{
+	//FIXME: calculate this properly, for now it is AF_split_sectors
+	return size_round_up(keylength * 4000, 4096);
+}
+
+static size_t get_min_offset(struct luks2_hdr *hdr)
+{
+	return 2 * hdr->hdr_size;
+}
+
+static size_t get_max_offset(struct luks2_hdr *hdr)
+{
+	return LUKS2_hdr_and_areas_size(hdr);
+}
+
+int LUKS2_find_area_max_gap(struct crypt_device *cd, struct luks2_hdr *hdr,
+			uint64_t *area_offset, uint64_t *area_length)
+{
+	struct area areas[LUKS2_KEYSLOTS_MAX], sorted_areas[LUKS2_KEYSLOTS_MAX+1] = {};
+	int i, j, k, area_i;
+	size_t valid_offset, offset, length;
+
+	/* fill area offset + length table */
+	for (i = 0; i < LUKS2_KEYSLOTS_MAX; i++) {
+		if (!LUKS2_keyslot_area(hdr, i, &areas[i].offset, &areas[i].length))
+			continue;
+		areas[i].length = 0;
+		areas[i].offset = 0;
+	}
+
+	/* sort table */
+	k = 0; /* index in sorted table */
+	for (i = 0; i < LUKS2_KEYSLOTS_MAX; i++) {
+		offset = get_max_offset(hdr) ?: UINT64_MAX;
+		area_i = -1;
+		/* search for the smallest offset in table */
+		for (j = 0; j < LUKS2_KEYSLOTS_MAX; j++)
+			if (areas[j].offset && areas[j].offset <= offset) {
+				area_i = j;
+				offset = areas[j].offset;
+			}
+
+		if (area_i >= 0) {
+			sorted_areas[k].length = areas[area_i].length;
+			sorted_areas[k].offset = areas[area_i].offset;
+			areas[area_i].length = 0;
+			areas[area_i].offset = 0;
+			k++;
+		}
+	}
+
+	sorted_areas[LUKS2_KEYSLOTS_MAX].offset = get_max_offset(hdr);
+	sorted_areas[LUKS2_KEYSLOTS_MAX].length = 1;
+
+	/* search for the gap we can use */
+	length = valid_offset = 0;
+	offset = get_min_offset(hdr);
+	for (i = 0; i < LUKS2_KEYSLOTS_MAX+1; i++) {
+		/* skip empty */
+		if (sorted_areas[i].offset == 0 || sorted_areas[i].length == 0)
+			continue;
+
+		/* found bigger gap than the last one */
+		if ((offset < sorted_areas[i].offset) && (sorted_areas[i].offset - offset) > length) {
+			length = sorted_areas[i].offset - offset;
+			valid_offset = offset;
+		}
+
+		/* move beyond allocated area */
+		offset = sorted_areas[i].offset + sorted_areas[i].length;
+	}
+
+	/* this search 'algorithm' does not work with unaligned areas */
+	assert(length == size_round_up(length, 4096));
+	assert(valid_offset == size_round_up(valid_offset, 4096));
+
+	if (!length) {
+		log_dbg(cd, "Not enough space in header keyslot area.");
+		return -EINVAL;
+	}
+
+	log_dbg(cd, "Found largest free area %zu -> %zu", valid_offset, length + valid_offset);
+
+	*area_offset = valid_offset;
+	*area_length = length;
+
+	return 0;
+}
+
+int LUKS2_find_area_gap(struct crypt_device *cd, struct luks2_hdr *hdr,
+			size_t keylength, uint64_t *area_offset, uint64_t *area_length)
+{
+	struct area areas[LUKS2_KEYSLOTS_MAX], sorted_areas[LUKS2_KEYSLOTS_MAX] = {};
+	int i, j, k, area_i;
+	size_t offset, length;
+
+	/* fill area offset + length table */
+	for (i = 0; i < LUKS2_KEYSLOTS_MAX; i++) {
+		if (!LUKS2_keyslot_area(hdr, i, &areas[i].offset, &areas[i].length))
+			continue;
+		areas[i].length = 0;
+		areas[i].offset = 0;
+	}
+
+	/* sort table */
+	k = 0; /* index in sorted table */
+	for (i = 0; i < LUKS2_KEYSLOTS_MAX; i++) {
+		offset = get_max_offset(hdr) ?: UINT64_MAX;
+		area_i = -1;
+		/* search for the smallest offset in table */
+		for (j = 0; j < LUKS2_KEYSLOTS_MAX; j++)
+			if (areas[j].offset && areas[j].offset <= offset) {
+				area_i = j;
+				offset = areas[j].offset;
+			}
+
+		if (area_i >= 0) {
+			sorted_areas[k].length = areas[area_i].length;
+			sorted_areas[k].offset = areas[area_i].offset;
+			areas[area_i].length = 0;
+			areas[area_i].offset = 0;
+			k++;
+		}
+	}
+
+	/* search for the gap we can use */
+	offset = get_min_offset(hdr);
+	length = get_area_size(keylength);
+	for (i = 0; i < LUKS2_KEYSLOTS_MAX; i++) {
+		/* skip empty */
+		if (sorted_areas[i].offset == 0 || sorted_areas[i].length == 0)
+			continue;
+
+		/* enough space before the used area */
+		if ((offset < sorted_areas[i].offset) && ((offset + length) <= sorted_areas[i].offset))
+			break;
+
+		/* both offset and length are already aligned to 4096 bytes */
+		offset = sorted_areas[i].offset + sorted_areas[i].length;
+	}
+
+	if ((offset + length) > get_max_offset(hdr)) {
+		log_dbg(cd, "Not enough space in header keyslot area.");
+		return -EINVAL;
+	}
+
+	log_dbg(cd, "Found area %zu -> %zu", offset, length + offset);
+
+	*area_offset = offset;
+	*area_length = length;
+	return 0;
+}
+
+int LUKS2_check_metadata_area_size(uint64_t metadata_size)
+{
+	/* see LUKS2_HDR2_OFFSETS */
+	return (metadata_size != 0x004000 &&
+		metadata_size != 0x008000 && metadata_size != 0x010000 &&
+		metadata_size != 0x020000 && metadata_size != 0x040000 &&
+		metadata_size != 0x080000 && metadata_size != 0x100000 &&
+		metadata_size != 0x200000 && metadata_size != 0x400000);
+}
+
+int LUKS2_check_keyslots_area_size(uint64_t keyslots_size)
+{
+	return (MISALIGNED_4K(keyslots_size) ||
+		keyslots_size > LUKS2_MAX_KEYSLOTS_SIZE);
+}
+
+int LUKS2_generate_hdr(
+	struct crypt_device *cd,
+	struct luks2_hdr *hdr,
+	const struct volume_key *vk,
+	const char *cipherName,
+	const char *cipherMode,
+	const char *integrity,
+	const char *uuid,
+	unsigned int sector_size,  /* in bytes */
+	uint64_t data_offset,      /* in bytes */
+	uint64_t align_offset,     /* in bytes */
+	uint64_t required_alignment,
+	uint64_t metadata_size,
+	uint64_t keyslots_size)
+{
+	struct json_object *jobj_segment, *jobj_integrity, *jobj_keyslots, *jobj_segments, *jobj_config;
+	char cipher[128];
+	uuid_t partitionUuid;
+	int r, digest;
+	uint64_t mdev_size;
+
+	if (!metadata_size)
+		metadata_size = LUKS2_HDR_16K_LEN;
+	hdr->hdr_size = metadata_size;
+
+	if (data_offset && data_offset < get_min_offset(hdr)) {
+		log_err(cd, _("Requested data offset is too small."));
+		return -EINVAL;
+	}
+
+	/* Increase keyslot size according to data offset */
+	if (!keyslots_size && data_offset)
+		keyslots_size = data_offset - get_min_offset(hdr);
+
+	/* keyslots size has to be 4 KiB aligned */
+	keyslots_size -= (keyslots_size % 4096);
+
+	if (keyslots_size > LUKS2_MAX_KEYSLOTS_SIZE)
+		keyslots_size = LUKS2_MAX_KEYSLOTS_SIZE;
+
+	if (!keyslots_size) {
+		assert(LUKS2_DEFAULT_HDR_SIZE > 2 * LUKS2_HDR_OFFSET_MAX);
+		keyslots_size = LUKS2_DEFAULT_HDR_SIZE - get_min_offset(hdr);
+		/* Decrease keyslots_size due to metadata device being too small */
+		if (!device_size(crypt_metadata_device(cd), &mdev_size) &&
+		    ((keyslots_size + get_min_offset(hdr)) > mdev_size) &&
+		    device_fallocate(crypt_metadata_device(cd), keyslots_size + get_min_offset(hdr)) &&
+		    (get_min_offset(hdr) <= mdev_size))
+			keyslots_size = mdev_size - get_min_offset(hdr);
+	}
+
+	/* Decrease keyslots_size if we have smaller data_offset */
+	if (data_offset && (keyslots_size + get_min_offset(hdr)) > data_offset) {
+		keyslots_size = data_offset - get_min_offset(hdr);
+		log_dbg(cd, "Decreasing keyslot area size to %" PRIu64
+			" bytes due to the requested data offset %"
+			PRIu64 " bytes.", keyslots_size, data_offset);
+	}
+
+	/* Data offset has priority */
+	if (!data_offset && required_alignment) {
+		data_offset = size_round_up(get_min_offset(hdr) + keyslots_size,
+					    (size_t)required_alignment);
+		data_offset += align_offset;
+	}
+
+	log_dbg(cd, "Formatting LUKS2 with JSON metadata area %" PRIu64
+		" bytes and keyslots area %" PRIu64 " bytes.",
+		metadata_size - LUKS2_HDR_BIN_LEN, keyslots_size);
+
+	if (keyslots_size < (LUKS2_HDR_OFFSET_MAX - 2*LUKS2_HDR_16K_LEN))
+		log_std(cd, _("WARNING: keyslots area (%" PRIu64 " bytes) is very small,"
+			" available LUKS2 keyslot count is very limited.\n"),
+			keyslots_size);
+
+	hdr->seqid = 1;
+	hdr->version = 2;
+	memset(hdr->label, 0, LUKS2_LABEL_L);
+	strcpy(hdr->checksum_alg, "sha256");
+	crypt_random_get(cd, (char*)hdr->salt1, LUKS2_SALT_L, CRYPT_RND_SALT);
+	crypt_random_get(cd, (char*)hdr->salt2, LUKS2_SALT_L, CRYPT_RND_SALT);
+
+	if (uuid && uuid_parse(uuid, partitionUuid) == -1) {
+		log_err(cd, _("Wrong LUKS UUID format provided."));
+		return -EINVAL;
+	}
+	if (!uuid)
+		uuid_generate(partitionUuid);
+
+	uuid_unparse(partitionUuid, hdr->uuid);
+
+	if (*cipherMode != '\0')
+		r = snprintf(cipher, sizeof(cipher), "%s-%s", cipherName, cipherMode);
+	else
+		r = snprintf(cipher, sizeof(cipher), "%s", cipherName);
+	if (r < 0 || (size_t)r >= sizeof(cipher))
+		return -EINVAL;
+
+	hdr->jobj = json_object_new_object();
+
+	jobj_keyslots = json_object_new_object();
+	json_object_object_add(hdr->jobj, "keyslots", jobj_keyslots);
+	json_object_object_add(hdr->jobj, "tokens", json_object_new_object());
+	jobj_segments = json_object_new_object();
+	json_object_object_add(hdr->jobj, "segments", jobj_segments);
+	json_object_object_add(hdr->jobj, "digests", json_object_new_object());
+	jobj_config = json_object_new_object();
+	json_object_object_add(hdr->jobj, "config", jobj_config);
+
+	digest = LUKS2_digest_create(cd, "pbkdf2", hdr, vk);
+	if (digest < 0)
+		goto err;
+
+	if (LUKS2_digest_segment_assign(cd, hdr, 0, digest, 1, 0) < 0)
+		goto err;
+
+	jobj_segment = json_segment_create_crypt(data_offset, 0, NULL, cipher, sector_size, 0);
+	if (!jobj_segment)
+		goto err;
+
+	if (integrity) {
+		jobj_integrity = json_object_new_object();
+		json_object_object_add(jobj_integrity, "type", json_object_new_string(integrity));
+		json_object_object_add(jobj_integrity, "journal_encryption", json_object_new_string("none"));
+		json_object_object_add(jobj_integrity, "journal_integrity", json_object_new_string("none"));
+		json_object_object_add(jobj_segment, "integrity", jobj_integrity);
+	}
+
+	json_object_object_add_by_uint(jobj_segments, 0, jobj_segment);
+
+	json_object_object_add(jobj_config, "json_size", crypt_jobj_new_uint64(metadata_size - LUKS2_HDR_BIN_LEN));
+	json_object_object_add(jobj_config, "keyslots_size", crypt_jobj_new_uint64(keyslots_size));
+
+	JSON_DBG(cd, hdr->jobj, "Header JSON:");
+	return 0;
+err:
+	json_object_put(hdr->jobj);
+	hdr->jobj = NULL;
+	return -EINVAL;
+}
+
+int LUKS2_wipe_header_areas(struct crypt_device *cd,
+	struct luks2_hdr *hdr, bool detached_header)
+{
+	int r;
+	uint64_t offset, length;
+	size_t wipe_block;
+
+	/* Wipe complete header, keyslots and padding areas with zeroes. */
+	offset = 0;
+	length = LUKS2_get_data_offset(hdr) * SECTOR_SIZE;
+	wipe_block = 1024 * 1024;
+
+	if (LUKS2_hdr_validate(cd, hdr->jobj, hdr->hdr_size - LUKS2_HDR_BIN_LEN))
+		return -EINVAL;
+
+	/* On detached header wipe at least the first 4k */
+	if (detached_header) {
+		length = 4096;
+		wipe_block = 4096;
+	}
+
+	log_dbg(cd, "Wiping LUKS areas (0x%06" PRIx64 " - 0x%06" PRIx64") with zeroes.",
+		offset, length + offset);
+
+	r = crypt_wipe_device(cd, crypt_metadata_device(cd), CRYPT_WIPE_ZERO,
+			      offset, length, wipe_block, NULL, NULL);
+	if (r < 0)
+		return r;
+
+	/* Wipe keyslot area */
+	wipe_block = 1024 * 1024;
+	offset = get_min_offset(hdr);
+	length = LUKS2_keyslots_size(hdr);
+
+	log_dbg(cd, "Wiping keyslots area (0x%06" PRIx64 " - 0x%06" PRIx64") with random data.",
+		offset, length + offset);
+
+	return crypt_wipe_device(cd, crypt_metadata_device(cd), CRYPT_WIPE_RANDOM,
+				 offset, length, wipe_block, NULL, NULL);
+}
+
+/* FIXME: what if user wanted to keep original keyslots size? */
+int LUKS2_set_keyslots_size(struct crypt_device *cd,
+		struct luks2_hdr *hdr,
+		uint64_t data_offset)
+{
+	json_object *jobj_config;
+	uint64_t keyslots_size;
+
+	if (data_offset < get_min_offset(hdr))
+		return 1;
+
+	keyslots_size = data_offset - get_min_offset(hdr);
+
+	/* keep keyslots_size reasonable for custom data alignments */
+	if (keyslots_size > LUKS2_MAX_KEYSLOTS_SIZE)
+		keyslots_size = LUKS2_MAX_KEYSLOTS_SIZE;
+
+	/* keyslots size has to be 4 KiB aligned */
+	keyslots_size -= (keyslots_size % 4096);
+
+	if (!json_object_object_get_ex(hdr->jobj, "config", &jobj_config))
+		return 1;
+
+	json_object_object_add(jobj_config, "keyslots_size", crypt_jobj_new_uint64(keyslots_size));
+	return 0;
+}