diff options
Diffstat (limited to 'lib/luks2/luks2_json_format.c')
| -rw-r--r-- | lib/luks2/luks2_json_format.c | 311 |
1 files changed, 311 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..a2cd331 --- /dev/null +++ b/lib/luks2/luks2_json_format.c @@ -0,0 +1,311 @@ +/* + * LUKS - Linux Unified Key Setup v2, LUKS2 header format code + * + * 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" +#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 crypt_device *cd) +{ + return crypt_get_data_offset(cd) * SECTOR_SIZE; +} + +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(cd) ?: 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 (get_max_offset(cd) && (offset + length) > get_max_offset(cd)) { + log_err(cd, _("No space for new keyslot.")); + return -EINVAL; + } + + log_dbg(cd, "Found area %zu -> %zu", offset, length + offset); +/* + log_dbg("Area offset min: %zu, max %zu, slots max %u", + get_min_offset(hdr), get_max_offset(cd), LUKS2_KEYSLOTS_MAX); + for (i = 0; i < LUKS2_KEYSLOTS_MAX; i++) + log_dbg("SLOT[%02i]: %-8" PRIu64 " -> %-8" PRIu64, i, + sorted_areas[i].offset, + sorted_areas[i].length + sorted_areas[i].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 digest; + + 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 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') + snprintf(cipher, sizeof(cipher), "%s-%s", cipherName, cipherMode); + else + snprintf(cipher, sizeof(cipher), "%s", cipherName); + + 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) { + json_object_put(hdr->jobj); + hdr->jobj = NULL; + return -EINVAL; + } + + if (LUKS2_digest_segment_assign(cd, hdr, CRYPT_DEFAULT_SEGMENT, digest, 1, 0) < 0) { + json_object_put(hdr->jobj); + hdr->jobj = NULL; + return -EINVAL; + } + + jobj_segment = json_object_new_object(); + json_object_object_add(jobj_segment, "type", json_object_new_string("crypt")); + json_object_object_add(jobj_segment, "offset", json_object_new_uint64(data_offset)); + json_object_object_add(jobj_segment, "iv_tweak", json_object_new_string("0")); + json_object_object_add(jobj_segment, "size", json_object_new_string("dynamic")); + json_object_object_add(jobj_segment, "encryption", json_object_new_string(cipher)); + json_object_object_add(jobj_segment, "sector_size", json_object_new_int(sector_size)); + + 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, CRYPT_DEFAULT_SEGMENT, jobj_segment); + + json_object_object_add(jobj_config, "json_size", json_object_new_uint64(metadata_size - LUKS2_HDR_BIN_LEN)); + json_object_object_add(jobj_config, "keyslots_size", json_object_new_uint64(keyslots_size)); + + JSON_DBG(cd, hdr->jobj, "Header JSON:"); + return 0; +} + +int LUKS2_wipe_header_areas(struct crypt_device *cd, + struct luks2_hdr *hdr) +{ + 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 (length == 0) { + 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->jobj); + + 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); +} |