diff options
Diffstat (limited to '')
| -rw-r--r-- | lib/luks1/keymanage.c | 1243 |
1 files changed, 1243 insertions, 0 deletions
diff --git a/lib/luks1/keymanage.c b/lib/luks1/keymanage.c new file mode 100644 index 0000000..e09f396 --- /dev/null +++ b/lib/luks1/keymanage.c @@ -0,0 +1,1243 @@ +/* + * LUKS - Linux Unified Key Setup + * + * Copyright (C) 2004-2006 Clemens Fruhwirth <clemens@endorphin.org> + * Copyright (C) 2009-2019 Red Hat, Inc. All rights reserved. + * Copyright (C) 2013-2019 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 <sys/types.h> +#include <sys/stat.h> +#include <netinet/in.h> +#include <fcntl.h> +#include <errno.h> +#include <unistd.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <ctype.h> +#include <assert.h> +#include <uuid/uuid.h> + +#include "luks.h" +#include "af.h" +#include "internal.h" + +int LUKS_keyslot_area(const struct luks_phdr *hdr, + int keyslot, + uint64_t *offset, + uint64_t *length) +{ + if(keyslot >= LUKS_NUMKEYS || keyslot < 0) + return -EINVAL; + + *offset = (uint64_t)hdr->keyblock[keyslot].keyMaterialOffset * SECTOR_SIZE; + *length = AF_split_sectors(hdr->keyBytes, LUKS_STRIPES) * SECTOR_SIZE; + + return 0; +} + +/* insertsort: because the array has 8 elements and it's mostly sorted. that's why */ +static void LUKS_sort_keyslots(const struct luks_phdr *hdr, int *array) +{ + int i, j, x; + + for (i = 1; i < LUKS_NUMKEYS; i++) { + j = i; + while (j > 0 && hdr->keyblock[array[j-1]].keyMaterialOffset > hdr->keyblock[array[j]].keyMaterialOffset) { + x = array[j]; + array[j] = array[j-1]; + array[j-1] = x; + j--; + } + } +} + +size_t LUKS_device_sectors(const struct luks_phdr *hdr) +{ + int sorted_areas[LUKS_NUMKEYS] = { 0, 1, 2, 3, 4, 5, 6, 7 }; + + LUKS_sort_keyslots(hdr, sorted_areas); + + return hdr->keyblock[sorted_areas[LUKS_NUMKEYS-1]].keyMaterialOffset + AF_split_sectors(hdr->keyBytes, LUKS_STRIPES); +} + +size_t LUKS_keyslots_offset(const struct luks_phdr *hdr) +{ + int sorted_areas[LUKS_NUMKEYS] = { 0, 1, 2, 3, 4, 5, 6, 7 }; + + LUKS_sort_keyslots(hdr, sorted_areas); + + return hdr->keyblock[sorted_areas[0]].keyMaterialOffset; +} + +static int LUKS_check_device_size(struct crypt_device *ctx, const struct luks_phdr *hdr, int falloc) +{ + struct device *device = crypt_metadata_device(ctx); + uint64_t dev_sectors, hdr_sectors; + + if (!hdr->keyBytes) + return -EINVAL; + + if (device_size(device, &dev_sectors)) { + log_dbg(ctx, "Cannot get device size for device %s.", device_path(device)); + return -EIO; + } + + dev_sectors >>= SECTOR_SHIFT; + hdr_sectors = LUKS_device_sectors(hdr); + log_dbg(ctx, "Key length %u, device size %" PRIu64 " sectors, header size %" + PRIu64 " sectors.", hdr->keyBytes, dev_sectors, hdr_sectors); + + if (hdr_sectors > dev_sectors) { + /* If it is header file, increase its size */ + if (falloc && !device_fallocate(device, hdr_sectors << SECTOR_SHIFT)) + return 0; + + log_err(ctx, _("Device %s is too small. (LUKS1 requires at least %" PRIu64 " bytes.)"), + device_path(device), hdr_sectors * SECTOR_SIZE); + return -EINVAL; + } + + return 0; +} + +static int LUKS_check_keyslots(struct crypt_device *ctx, const struct luks_phdr *phdr) +{ + int i, prev, next, sorted_areas[LUKS_NUMKEYS] = { 0, 1, 2, 3, 4, 5, 6, 7 }; + uint32_t secs_per_stripes = AF_split_sectors(phdr->keyBytes, LUKS_STRIPES); + + LUKS_sort_keyslots(phdr, sorted_areas); + + /* Check keyslot to prevent access outside of header and keyslot area */ + for (i = 0; i < LUKS_NUMKEYS; i++) { + /* enforce stripes == 4000 */ + if (phdr->keyblock[i].stripes != LUKS_STRIPES) { + log_dbg(ctx, "Invalid stripes count %u in keyslot %u.", + phdr->keyblock[i].stripes, i); + log_err(ctx, _("LUKS keyslot %u is invalid."), i); + return -1; + } + + /* First sectors is the header itself */ + if (phdr->keyblock[i].keyMaterialOffset * SECTOR_SIZE < sizeof(*phdr)) { + log_dbg(ctx, "Invalid offset %u in keyslot %u.", + phdr->keyblock[i].keyMaterialOffset, i); + log_err(ctx, _("LUKS keyslot %u is invalid."), i); + return -1; + } + + /* Ignore following check for detached header where offset can be zero. */ + if (phdr->payloadOffset == 0) + continue; + + if (phdr->payloadOffset <= phdr->keyblock[i].keyMaterialOffset) { + log_dbg(ctx, "Invalid offset %u in keyslot %u (beyond data area offset %u).", + phdr->keyblock[i].keyMaterialOffset, i, + phdr->payloadOffset); + log_err(ctx, _("LUKS keyslot %u is invalid."), i); + return -1; + } + + if (phdr->payloadOffset < (phdr->keyblock[i].keyMaterialOffset + secs_per_stripes)) { + log_dbg(ctx, "Invalid keyslot size %u (offset %u, stripes %u) in " + "keyslot %u (beyond data area offset %u).", + secs_per_stripes, + phdr->keyblock[i].keyMaterialOffset, + phdr->keyblock[i].stripes, + i, phdr->payloadOffset); + log_err(ctx, _("LUKS keyslot %u is invalid."), i); + return -1; + } + } + + /* check no keyslot overlaps with each other */ + for (i = 1; i < LUKS_NUMKEYS; i++) { + prev = sorted_areas[i-1]; + next = sorted_areas[i]; + if (phdr->keyblock[next].keyMaterialOffset < + (phdr->keyblock[prev].keyMaterialOffset + secs_per_stripes)) { + log_dbg(ctx, "Not enough space in LUKS keyslot %d.", prev); + log_err(ctx, _("LUKS keyslot %u is invalid."), prev); + return -1; + } + } + /* do not check last keyslot on purpose, it must be tested in device size check */ + + return 0; +} + +static const char *dbg_slot_state(crypt_keyslot_info ki) +{ + switch(ki) { + case CRYPT_SLOT_INACTIVE: + return "INACTIVE"; + case CRYPT_SLOT_ACTIVE: + return "ACTIVE"; + case CRYPT_SLOT_ACTIVE_LAST: + return "ACTIVE_LAST"; + case CRYPT_SLOT_INVALID: + default: + return "INVALID"; + } +} + +int LUKS_hdr_backup(const char *backup_file, struct crypt_device *ctx) +{ + struct device *device = crypt_metadata_device(ctx); + struct luks_phdr hdr; + int r = 0, devfd = -1; + size_t hdr_size; + size_t buffer_size; + char *buffer = NULL; + + r = LUKS_read_phdr(&hdr, 1, 0, ctx); + if (r) + return r; + + hdr_size = LUKS_device_sectors(&hdr) << SECTOR_SHIFT; + buffer_size = size_round_up(hdr_size, crypt_getpagesize()); + + buffer = crypt_safe_alloc(buffer_size); + if (!buffer || hdr_size < LUKS_ALIGN_KEYSLOTS || hdr_size > buffer_size) { + r = -ENOMEM; + goto out; + } + + log_dbg(ctx, "Storing backup of header (%zu bytes) and keyslot area (%zu bytes).", + sizeof(hdr), hdr_size - LUKS_ALIGN_KEYSLOTS); + + log_dbg(ctx, "Output backup file size: %zu bytes.", buffer_size); + + devfd = device_open(ctx, device, O_RDONLY); + if (devfd < 0) { + log_err(ctx, _("Device %s is not a valid LUKS device."), device_path(device)); + r = -EINVAL; + goto out; + } + + if (read_blockwise(devfd, device_block_size(ctx, device), device_alignment(device), + buffer, hdr_size) < (ssize_t)hdr_size) { + r = -EIO; + goto out; + } + close(devfd); + + /* Wipe unused area, so backup cannot contain old signatures */ + if (hdr.keyblock[0].keyMaterialOffset * SECTOR_SIZE == LUKS_ALIGN_KEYSLOTS) + memset(buffer + sizeof(hdr), 0, LUKS_ALIGN_KEYSLOTS - sizeof(hdr)); + + devfd = open(backup_file, O_CREAT|O_EXCL|O_WRONLY, S_IRUSR); + if (devfd == -1) { + if (errno == EEXIST) + log_err(ctx, _("Requested header backup file %s already exists."), backup_file); + else + log_err(ctx, _("Cannot create header backup file %s."), backup_file); + r = -EINVAL; + goto out; + } + if (write_buffer(devfd, buffer, buffer_size) < (ssize_t)buffer_size) { + log_err(ctx, _("Cannot write header backup file %s."), backup_file); + r = -EIO; + goto out; + } + + r = 0; +out: + if (devfd >= 0) + close(devfd); + crypt_memzero(&hdr, sizeof(hdr)); + crypt_safe_free(buffer); + return r; +} + +int LUKS_hdr_restore( + const char *backup_file, + struct luks_phdr *hdr, + struct crypt_device *ctx) +{ + struct device *device = crypt_metadata_device(ctx); + int r = 0, devfd = -1, diff_uuid = 0; + ssize_t buffer_size = 0; + char *buffer = NULL, msg[200]; + struct luks_phdr hdr_file; + + r = LUKS_read_phdr_backup(backup_file, &hdr_file, 0, ctx); + if (r == -ENOENT) + return r; + + if (!r) + buffer_size = LUKS_device_sectors(&hdr_file) << SECTOR_SHIFT; + + if (r || buffer_size < LUKS_ALIGN_KEYSLOTS) { + log_err(ctx, _("Backup file doesn't contain valid LUKS header.")); + r = -EINVAL; + goto out; + } + + buffer = crypt_safe_alloc(buffer_size); + if (!buffer) { + r = -ENOMEM; + goto out; + } + + devfd = open(backup_file, O_RDONLY); + if (devfd == -1) { + log_err(ctx, _("Cannot open header backup file %s."), backup_file); + r = -EINVAL; + goto out; + } + + if (read_buffer(devfd, buffer, buffer_size) < buffer_size) { + log_err(ctx, _("Cannot read header backup file %s."), backup_file); + r = -EIO; + goto out; + } + close(devfd); + devfd = -1; + + r = LUKS_read_phdr(hdr, 0, 0, ctx); + if (r == 0) { + log_dbg(ctx, "Device %s already contains LUKS header, checking UUID and offset.", device_path(device)); + if(hdr->payloadOffset != hdr_file.payloadOffset || + hdr->keyBytes != hdr_file.keyBytes) { + log_err(ctx, _("Data offset or key size differs on device and backup, restore failed.")); + r = -EINVAL; + goto out; + } + if (memcmp(hdr->uuid, hdr_file.uuid, UUID_STRING_L)) + diff_uuid = 1; + } + + if (snprintf(msg, sizeof(msg), _("Device %s %s%s"), device_path(device), + r ? _("does not contain LUKS header. Replacing header can destroy data on that device.") : + _("already contains LUKS header. Replacing header will destroy existing keyslots."), + diff_uuid ? _("\nWARNING: real device header has different UUID than backup!") : "") < 0) { + r = -ENOMEM; + goto out; + } + + if (!crypt_confirm(ctx, msg)) { + r = -EINVAL; + goto out; + } + + log_dbg(ctx, "Storing backup of header (%zu bytes) and keyslot area (%zu bytes) to device %s.", + sizeof(*hdr), buffer_size - LUKS_ALIGN_KEYSLOTS, device_path(device)); + + devfd = device_open(ctx, device, O_RDWR); + if (devfd < 0) { + if (errno == EACCES) + log_err(ctx, _("Cannot write to device %s, permission denied."), + device_path(device)); + else + log_err(ctx, _("Cannot open device %s."), device_path(device)); + r = -EINVAL; + goto out; + } + + if (write_blockwise(devfd, device_block_size(ctx, device), device_alignment(device), + buffer, buffer_size) < buffer_size) { + r = -EIO; + goto out; + } + close(devfd); + devfd = -1; + + /* Be sure to reload new data */ + r = LUKS_read_phdr(hdr, 1, 0, ctx); +out: + if (devfd >= 0) { + device_sync(ctx, device, devfd); + close(devfd); + } + crypt_safe_free(buffer); + return r; +} + +/* This routine should do some just basic recovery for known problems. */ +static int _keyslot_repair(struct luks_phdr *phdr, struct crypt_device *ctx) +{ + struct luks_phdr temp_phdr; + const unsigned char *sector = (const unsigned char*)phdr; + struct volume_key *vk; + int i, bad, r, need_write = 0; + + if (phdr->keyBytes != 16 && phdr->keyBytes != 32 && phdr->keyBytes != 64) { + log_err(ctx, _("Non standard key size, manual repair required.")); + return -EINVAL; + } + /* cryptsetup 1.0 did not align to 4k, cannot repair this one */ + if (LUKS_keyslots_offset(phdr) < (LUKS_ALIGN_KEYSLOTS / SECTOR_SIZE)) { + log_err(ctx, _("Non standard keyslots alignment, manual repair required.")); + return -EINVAL; + } + + r = LUKS_check_cipher(ctx, phdr->keyBytes, phdr->cipherName, phdr->cipherMode); + if (r < 0) + return -EINVAL; + + vk = crypt_alloc_volume_key(phdr->keyBytes, NULL); + + log_verbose(ctx, _("Repairing keyslots.")); + + log_dbg(ctx, "Generating second header with the same parameters for check."); + /* cipherName, cipherMode, hashSpec, uuid are already null terminated */ + /* payloadOffset - cannot check */ + r = LUKS_generate_phdr(&temp_phdr, vk, phdr->cipherName, phdr->cipherMode, + phdr->hashSpec, phdr->uuid, + phdr->payloadOffset * SECTOR_SIZE, 0, 0, ctx); + if (r < 0) + goto out; + + for(i = 0; i < LUKS_NUMKEYS; ++i) { + if (phdr->keyblock[i].active == LUKS_KEY_ENABLED) { + log_dbg(ctx, "Skipping repair for active keyslot %i.", i); + continue; + } + + bad = 0; + if (phdr->keyblock[i].keyMaterialOffset != temp_phdr.keyblock[i].keyMaterialOffset) { + log_err(ctx, _("Keyslot %i: offset repaired (%u -> %u)."), i, + (unsigned)phdr->keyblock[i].keyMaterialOffset, + (unsigned)temp_phdr.keyblock[i].keyMaterialOffset); + phdr->keyblock[i].keyMaterialOffset = temp_phdr.keyblock[i].keyMaterialOffset; + bad = 1; + } + + if (phdr->keyblock[i].stripes != temp_phdr.keyblock[i].stripes) { + log_err(ctx, _("Keyslot %i: stripes repaired (%u -> %u)."), i, + (unsigned)phdr->keyblock[i].stripes, + (unsigned)temp_phdr.keyblock[i].stripes); + phdr->keyblock[i].stripes = temp_phdr.keyblock[i].stripes; + bad = 1; + } + + /* Known case - MSDOS partition table signature */ + if (i == 6 && sector[0x1fe] == 0x55 && sector[0x1ff] == 0xaa) { + log_err(ctx, _("Keyslot %i: bogus partition signature."), i); + bad = 1; + } + + if(bad) { + log_err(ctx, _("Keyslot %i: salt wiped."), i); + phdr->keyblock[i].active = LUKS_KEY_DISABLED; + memset(&phdr->keyblock[i].passwordSalt, 0x00, LUKS_SALTSIZE); + phdr->keyblock[i].passwordIterations = 0; + } + + if (bad) + need_write = 1; + } + + /* + * check repair result before writing because repair can't fix out of order + * keyslot offsets and would corrupt header again + */ + if (LUKS_check_keyslots(ctx, phdr)) + r = -EINVAL; + else if (need_write) { + log_verbose(ctx, _("Writing LUKS header to disk.")); + r = LUKS_write_phdr(phdr, ctx); + } +out: + if (r) + log_err(ctx, _("Repair failed.")); + crypt_free_volume_key(vk); + crypt_memzero(&temp_phdr, sizeof(temp_phdr)); + return r; +} + +static int _check_and_convert_hdr(const char *device, + struct luks_phdr *hdr, + int require_luks_device, + int repair, + struct crypt_device *ctx) +{ + int r = 0; + unsigned int i; + char luksMagic[] = LUKS_MAGIC; + + if(memcmp(hdr->magic, luksMagic, LUKS_MAGIC_L)) { /* Check magic */ + log_dbg(ctx, "LUKS header not detected."); + if (require_luks_device) + log_err(ctx, _("Device %s is not a valid LUKS device."), device); + return -EINVAL; + } else if((hdr->version = ntohs(hdr->version)) != 1) { /* Convert every uint16/32_t item from network byte order */ + log_err(ctx, _("Unsupported LUKS version %d."), hdr->version); + return -EINVAL; + } + + hdr->hashSpec[LUKS_HASHSPEC_L - 1] = '\0'; + if (crypt_hmac_size(hdr->hashSpec) < LUKS_DIGESTSIZE) { + log_err(ctx, _("Requested LUKS hash %s is not supported."), hdr->hashSpec); + return -EINVAL; + } + + /* Header detected */ + hdr->payloadOffset = ntohl(hdr->payloadOffset); + hdr->keyBytes = ntohl(hdr->keyBytes); + hdr->mkDigestIterations = ntohl(hdr->mkDigestIterations); + + for(i = 0; i < LUKS_NUMKEYS; ++i) { + hdr->keyblock[i].active = ntohl(hdr->keyblock[i].active); + hdr->keyblock[i].passwordIterations = ntohl(hdr->keyblock[i].passwordIterations); + hdr->keyblock[i].keyMaterialOffset = ntohl(hdr->keyblock[i].keyMaterialOffset); + hdr->keyblock[i].stripes = ntohl(hdr->keyblock[i].stripes); + } + + if (LUKS_check_keyslots(ctx, hdr)) + r = -EINVAL; + + /* Avoid unterminated strings */ + hdr->cipherName[LUKS_CIPHERNAME_L - 1] = '\0'; + hdr->cipherMode[LUKS_CIPHERMODE_L - 1] = '\0'; + hdr->uuid[UUID_STRING_L - 1] = '\0'; + + if (repair) { + if (r == -EINVAL) + r = _keyslot_repair(hdr, ctx); + else + log_verbose(ctx, _("No known problems detected for LUKS header.")); + } + + return r; +} + +static void _to_lower(char *str, unsigned max_len) +{ + for(; *str && max_len; str++, max_len--) + if (isupper(*str)) + *str = tolower(*str); +} + +static void LUKS_fix_header_compatible(struct luks_phdr *header) +{ + /* Old cryptsetup expects "sha1", gcrypt allows case insensitive names, + * so always convert hash to lower case in header */ + _to_lower(header->hashSpec, LUKS_HASHSPEC_L); + + /* ECB mode does not use IV but dmcrypt silently allows it. + * Drop any IV here if ECB is used (that is not secure anyway).*/ + if (!strncmp(header->cipherMode, "ecb-", 4)) { + memset(header->cipherMode, 0, LUKS_CIPHERMODE_L); + strcpy(header->cipherMode, "ecb"); + } +} + +int LUKS_read_phdr_backup(const char *backup_file, + struct luks_phdr *hdr, + int require_luks_device, + struct crypt_device *ctx) +{ + ssize_t hdr_size = sizeof(struct luks_phdr); + int devfd = 0, r = 0; + + log_dbg(ctx, "Reading LUKS header of size %d from backup file %s", + (int)hdr_size, backup_file); + + devfd = open(backup_file, O_RDONLY); + if (devfd == -1) { + log_err(ctx, _("Cannot open header backup file %s."), backup_file); + return -ENOENT; + } + + if (read_buffer(devfd, hdr, hdr_size) < hdr_size) + r = -EIO; + else { + LUKS_fix_header_compatible(hdr); + r = _check_and_convert_hdr(backup_file, hdr, + require_luks_device, 0, ctx); + } + + close(devfd); + return r; +} + +int LUKS_read_phdr(struct luks_phdr *hdr, + int require_luks_device, + int repair, + struct crypt_device *ctx) +{ + struct device *device = crypt_metadata_device(ctx); + ssize_t hdr_size = sizeof(struct luks_phdr); + int devfd = 0, r = 0; + + /* LUKS header starts at offset 0, first keyslot on LUKS_ALIGN_KEYSLOTS */ + assert(sizeof(struct luks_phdr) <= LUKS_ALIGN_KEYSLOTS); + + /* Stripes count cannot be changed without additional code fixes yet */ + assert(LUKS_STRIPES == 4000); + + if (repair && !require_luks_device) + return -EINVAL; + + log_dbg(ctx, "Reading LUKS header of size %zu from device %s", + hdr_size, device_path(device)); + + devfd = device_open(ctx, device, O_RDONLY); + if (devfd < 0) { + log_err(ctx, _("Cannot open device %s."), device_path(device)); + return -EINVAL; + } + + if (read_blockwise(devfd, device_block_size(ctx, device), device_alignment(device), + hdr, hdr_size) < hdr_size) + r = -EIO; + else + r = _check_and_convert_hdr(device_path(device), hdr, require_luks_device, + repair, ctx); + + if (!r) + r = LUKS_check_device_size(ctx, hdr, 0); + + /* + * Cryptsetup 1.0.0 did not align keyslots to 4k (very rare version). + * Disable direct-io to avoid possible IO errors if underlying device + * has bigger sector size. + */ + if (!r && hdr->keyblock[0].keyMaterialOffset * SECTOR_SIZE < LUKS_ALIGN_KEYSLOTS) { + log_dbg(ctx, "Old unaligned LUKS keyslot detected, disabling direct-io."); + device_disable_direct_io(device); + } + + close(devfd); + return r; +} + +int LUKS_write_phdr(struct luks_phdr *hdr, + struct crypt_device *ctx) +{ + struct device *device = crypt_metadata_device(ctx); + ssize_t hdr_size = sizeof(struct luks_phdr); + int devfd = 0; + unsigned int i; + struct luks_phdr convHdr; + int r; + + log_dbg(ctx, "Updating LUKS header of size %zu on device %s", + sizeof(struct luks_phdr), device_path(device)); + + r = LUKS_check_device_size(ctx, hdr, 1); + if (r) + return r; + + devfd = device_open(ctx, device, O_RDWR); + if (devfd < 0) { + if (errno == EACCES) + log_err(ctx, _("Cannot write to device %s, permission denied."), + device_path(device)); + else + log_err(ctx, _("Cannot open device %s."), device_path(device)); + return -EINVAL; + } + + memcpy(&convHdr, hdr, hdr_size); + memset(&convHdr._padding, 0, sizeof(convHdr._padding)); + + /* Convert every uint16/32_t item to network byte order */ + convHdr.version = htons(hdr->version); + convHdr.payloadOffset = htonl(hdr->payloadOffset); + convHdr.keyBytes = htonl(hdr->keyBytes); + convHdr.mkDigestIterations = htonl(hdr->mkDigestIterations); + for(i = 0; i < LUKS_NUMKEYS; ++i) { + convHdr.keyblock[i].active = htonl(hdr->keyblock[i].active); + convHdr.keyblock[i].passwordIterations = htonl(hdr->keyblock[i].passwordIterations); + convHdr.keyblock[i].keyMaterialOffset = htonl(hdr->keyblock[i].keyMaterialOffset); + convHdr.keyblock[i].stripes = htonl(hdr->keyblock[i].stripes); + } + + r = write_blockwise(devfd, device_block_size(ctx, device), device_alignment(device), + &convHdr, hdr_size) < hdr_size ? -EIO : 0; + if (r) + log_err(ctx, _("Error during update of LUKS header on device %s."), device_path(device)); + + device_sync(ctx, device, devfd); + close(devfd); + + /* Re-read header from disk to be sure that in-memory and on-disk data are the same. */ + if (!r) { + r = LUKS_read_phdr(hdr, 1, 0, ctx); + if (r) + log_err(ctx, _("Error re-reading LUKS header after update on device %s."), + device_path(device)); + } + + return r; +} + +/* Check that kernel supports requested cipher by decryption of one sector */ +int LUKS_check_cipher(struct crypt_device *ctx, size_t keylength, const char *cipher, const char *cipher_mode) +{ + int r; + struct volume_key *empty_key; + char buf[SECTOR_SIZE]; + + log_dbg(ctx, "Checking if cipher %s-%s is usable.", cipher, cipher_mode); + + empty_key = crypt_alloc_volume_key(keylength, NULL); + if (!empty_key) + return -ENOMEM; + + /* No need to get KEY quality random but it must avoid known weak keys. */ + r = crypt_random_get(ctx, empty_key->key, empty_key->keylength, CRYPT_RND_NORMAL); + if (!r) + r = LUKS_decrypt_from_storage(buf, sizeof(buf), cipher, cipher_mode, empty_key, 0, ctx); + + crypt_free_volume_key(empty_key); + crypt_memzero(buf, sizeof(buf)); + return r; +} + +int LUKS_generate_phdr(struct luks_phdr *header, + const struct volume_key *vk, + const char *cipherName, + const char *cipherMode, + const char *hashSpec, + const char *uuid, + uint64_t data_offset, /* in bytes */ + uint64_t align_offset, /* in bytes */ + uint64_t required_alignment, /* in bytes */ + struct crypt_device *ctx) +{ + int i, r; + size_t keyslot_sectors, header_sectors; + uuid_t partitionUuid; + struct crypt_pbkdf_type *pbkdf; + double PBKDF2_temp; + char luksMagic[] = LUKS_MAGIC; + + if (data_offset % SECTOR_SIZE || align_offset % SECTOR_SIZE || + required_alignment % SECTOR_SIZE) + return -EINVAL; + + memset(header, 0, sizeof(struct luks_phdr)); + + keyslot_sectors = AF_split_sectors(vk->keylength, LUKS_STRIPES); + header_sectors = LUKS_ALIGN_KEYSLOTS / SECTOR_SIZE; + + for (i = 0; i < LUKS_NUMKEYS; i++) { + header->keyblock[i].active = LUKS_KEY_DISABLED; + header->keyblock[i].keyMaterialOffset = header_sectors; + header->keyblock[i].stripes = LUKS_STRIPES; + header_sectors = size_round_up(header_sectors + keyslot_sectors, + LUKS_ALIGN_KEYSLOTS / SECTOR_SIZE); + } + /* In sector is now size of all keyslot material space */ + + /* Data offset has priority */ + if (data_offset) + header->payloadOffset = data_offset / SECTOR_SIZE; + else if (required_alignment) { + header->payloadOffset = size_round_up(header_sectors, (required_alignment / SECTOR_SIZE)); + header->payloadOffset += (align_offset / SECTOR_SIZE); + } else + header->payloadOffset = 0; + + if (header->payloadOffset && header->payloadOffset < header_sectors) { + log_err(ctx, _("Data offset for LUKS header must be " + "either 0 or higher than header size.")); + return -EINVAL; + } + + if (crypt_hmac_size(hashSpec) < LUKS_DIGESTSIZE) { + log_err(ctx, _("Requested LUKS hash %s is not supported."), hashSpec); + return -EINVAL; + } + + if (uuid && uuid_parse(uuid, partitionUuid) == -1) { + log_err(ctx, _("Wrong LUKS UUID format provided.")); + return -EINVAL; + } + if (!uuid) + uuid_generate(partitionUuid); + + /* Set Magic */ + memcpy(header->magic,luksMagic,LUKS_MAGIC_L); + header->version=1; + strncpy(header->cipherName,cipherName,LUKS_CIPHERNAME_L-1); + strncpy(header->cipherMode,cipherMode,LUKS_CIPHERMODE_L-1); + strncpy(header->hashSpec,hashSpec,LUKS_HASHSPEC_L-1); + + header->keyBytes=vk->keylength; + + LUKS_fix_header_compatible(header); + + log_dbg(ctx, "Generating LUKS header version %d using hash %s, %s, %s, MK %d bytes", + header->version, header->hashSpec ,header->cipherName, header->cipherMode, + header->keyBytes); + + r = crypt_random_get(ctx, header->mkDigestSalt, LUKS_SALTSIZE, CRYPT_RND_SALT); + if(r < 0) { + log_err(ctx, _("Cannot create LUKS header: reading random salt failed.")); + return r; + } + + /* Compute master key digest */ + pbkdf = crypt_get_pbkdf(ctx); + r = crypt_benchmark_pbkdf_internal(ctx, pbkdf, vk->keylength); + if (r < 0) + return r; + assert(pbkdf->iterations); + + PBKDF2_temp = (double)pbkdf->iterations * LUKS_MKD_ITERATIONS_MS / pbkdf->time_ms; + if (PBKDF2_temp > (double)UINT32_MAX) + return -EINVAL; + header->mkDigestIterations = at_least((uint32_t)PBKDF2_temp, LUKS_MKD_ITERATIONS_MIN); + + r = crypt_pbkdf(CRYPT_KDF_PBKDF2, header->hashSpec, vk->key,vk->keylength, + header->mkDigestSalt, LUKS_SALTSIZE, + header->mkDigest,LUKS_DIGESTSIZE, + header->mkDigestIterations, 0, 0); + if (r < 0) { + log_err(ctx, _("Cannot create LUKS header: header digest failed (using hash %s)."), + header->hashSpec); + return r; + } + + uuid_unparse(partitionUuid, header->uuid); + + log_dbg(ctx, "Data offset %d, UUID %s, digest iterations %" PRIu32, + header->payloadOffset, header->uuid, header->mkDigestIterations); + + return 0; +} + +int LUKS_hdr_uuid_set( + struct luks_phdr *hdr, + const char *uuid, + struct crypt_device *ctx) +{ + uuid_t partitionUuid; + + if (uuid && uuid_parse(uuid, partitionUuid) == -1) { + log_err(ctx, _("Wrong LUKS UUID format provided.")); + return -EINVAL; + } + if (!uuid) + uuid_generate(partitionUuid); + + uuid_unparse(partitionUuid, hdr->uuid); + + return LUKS_write_phdr(hdr, ctx); +} + +int LUKS_set_key(unsigned int keyIndex, + const char *password, size_t passwordLen, + struct luks_phdr *hdr, struct volume_key *vk, + struct crypt_device *ctx) +{ + struct volume_key *derived_key; + char *AfKey = NULL; + size_t AFEKSize; + struct crypt_pbkdf_type *pbkdf; + int r; + + if(hdr->keyblock[keyIndex].active != LUKS_KEY_DISABLED) { + log_err(ctx, _("Key slot %d active, purge first."), keyIndex); + return -EINVAL; + } + + /* LUKS keyslot has always at least 4000 stripes according to specification */ + if(hdr->keyblock[keyIndex].stripes < 4000) { + log_err(ctx, _("Key slot %d material includes too few stripes. Header manipulation?"), + keyIndex); + return -EINVAL; + } + + log_dbg(ctx, "Calculating data for key slot %d", keyIndex); + pbkdf = crypt_get_pbkdf(ctx); + r = crypt_benchmark_pbkdf_internal(ctx, pbkdf, vk->keylength); + if (r < 0) + return r; + assert(pbkdf->iterations); + + /* + * Final iteration count is at least LUKS_SLOT_ITERATIONS_MIN + */ + hdr->keyblock[keyIndex].passwordIterations = + at_least(pbkdf->iterations, LUKS_SLOT_ITERATIONS_MIN); + log_dbg(ctx, "Key slot %d use %" PRIu32 " password iterations.", keyIndex, + hdr->keyblock[keyIndex].passwordIterations); + + derived_key = crypt_alloc_volume_key(hdr->keyBytes, NULL); + if (!derived_key) + return -ENOMEM; + + r = crypt_random_get(ctx, hdr->keyblock[keyIndex].passwordSalt, + LUKS_SALTSIZE, CRYPT_RND_SALT); + if (r < 0) + goto out; + + r = crypt_pbkdf(CRYPT_KDF_PBKDF2, hdr->hashSpec, password, passwordLen, + hdr->keyblock[keyIndex].passwordSalt, LUKS_SALTSIZE, + derived_key->key, hdr->keyBytes, + hdr->keyblock[keyIndex].passwordIterations, 0, 0); + if (r < 0) + goto out; + + /* + * AF splitting, the masterkey stored in vk->key is split to AfKey + */ + assert(vk->keylength == hdr->keyBytes); + AFEKSize = AF_split_sectors(vk->keylength, hdr->keyblock[keyIndex].stripes) * SECTOR_SIZE; + AfKey = crypt_safe_alloc(AFEKSize); + if (!AfKey) { + r = -ENOMEM; + goto out; + } + + log_dbg(ctx, "Using hash %s for AF in key slot %d, %d stripes", + hdr->hashSpec, keyIndex, hdr->keyblock[keyIndex].stripes); + r = AF_split(ctx, vk->key, AfKey, vk->keylength, hdr->keyblock[keyIndex].stripes, hdr->hashSpec); + if (r < 0) + goto out; + + log_dbg(ctx, "Updating key slot %d [0x%04x] area.", keyIndex, + hdr->keyblock[keyIndex].keyMaterialOffset << 9); + /* Encryption via dm */ + r = LUKS_encrypt_to_storage(AfKey, + AFEKSize, + hdr->cipherName, hdr->cipherMode, + derived_key, + hdr->keyblock[keyIndex].keyMaterialOffset, + ctx); + if (r < 0) + goto out; + + /* Mark the key as active in phdr */ + r = LUKS_keyslot_set(hdr, (int)keyIndex, 1, ctx); + if (r < 0) + goto out; + + r = LUKS_write_phdr(hdr, ctx); + if (r < 0) + goto out; + + r = 0; +out: + crypt_safe_free(AfKey); + crypt_free_volume_key(derived_key); + return r; +} + +/* Check whether a volume key is invalid. */ +int LUKS_verify_volume_key(const struct luks_phdr *hdr, + const struct volume_key *vk) +{ + char checkHashBuf[LUKS_DIGESTSIZE]; + + if (crypt_pbkdf(CRYPT_KDF_PBKDF2, hdr->hashSpec, vk->key, vk->keylength, + hdr->mkDigestSalt, LUKS_SALTSIZE, + checkHashBuf, LUKS_DIGESTSIZE, + hdr->mkDigestIterations, 0, 0) < 0) + return -EINVAL; + + if (memcmp(checkHashBuf, hdr->mkDigest, LUKS_DIGESTSIZE)) + return -EPERM; + + return 0; +} + +/* Try to open a particular key slot */ +static int LUKS_open_key(unsigned int keyIndex, + const char *password, + size_t passwordLen, + struct luks_phdr *hdr, + struct volume_key *vk, + struct crypt_device *ctx) +{ + crypt_keyslot_info ki = LUKS_keyslot_info(hdr, keyIndex); + struct volume_key *derived_key; + char *AfKey; + size_t AFEKSize; + int r; + + log_dbg(ctx, "Trying to open key slot %d [%s].", keyIndex, + dbg_slot_state(ki)); + + if (ki < CRYPT_SLOT_ACTIVE) + return -ENOENT; + + derived_key = crypt_alloc_volume_key(hdr->keyBytes, NULL); + if (!derived_key) + return -ENOMEM; + + assert(vk->keylength == hdr->keyBytes); + AFEKSize = AF_split_sectors(vk->keylength, hdr->keyblock[keyIndex].stripes) * SECTOR_SIZE; + AfKey = crypt_safe_alloc(AFEKSize); + if (!AfKey) { + r = -ENOMEM; + goto out; + } + + r = crypt_pbkdf(CRYPT_KDF_PBKDF2, hdr->hashSpec, password, passwordLen, + hdr->keyblock[keyIndex].passwordSalt, LUKS_SALTSIZE, + derived_key->key, hdr->keyBytes, + hdr->keyblock[keyIndex].passwordIterations, 0, 0); + if (r < 0) + goto out; + + log_dbg(ctx, "Reading key slot %d area.", keyIndex); + r = LUKS_decrypt_from_storage(AfKey, + AFEKSize, + hdr->cipherName, hdr->cipherMode, + derived_key, + hdr->keyblock[keyIndex].keyMaterialOffset, + ctx); + if (r < 0) + goto out; + + r = AF_merge(ctx, AfKey, vk->key, vk->keylength, hdr->keyblock[keyIndex].stripes, hdr->hashSpec); + if (r < 0) + goto out; + + r = LUKS_verify_volume_key(hdr, vk); + + /* Allow only empty passphrase with null cipher */ + if (!r && !strcmp(hdr->cipherName, "cipher_null") && passwordLen) + r = -EPERM; +out: + crypt_safe_free(AfKey); + crypt_free_volume_key(derived_key); + return r; +} + +int LUKS_open_key_with_hdr(int keyIndex, + const char *password, + size_t passwordLen, + struct luks_phdr *hdr, + struct volume_key **vk, + struct crypt_device *ctx) +{ + unsigned int i; + int r; + + *vk = crypt_alloc_volume_key(hdr->keyBytes, NULL); + + if (keyIndex >= 0) { + r = LUKS_open_key(keyIndex, password, passwordLen, hdr, *vk, ctx); + return (r < 0) ? r : keyIndex; + } + + for(i = 0; i < LUKS_NUMKEYS; i++) { + r = LUKS_open_key(i, password, passwordLen, hdr, *vk, ctx); + if(r == 0) + return i; + + /* Do not retry for errors that are no -EPERM or -ENOENT, + former meaning password wrong, latter key slot inactive */ + if ((r != -EPERM) && (r != -ENOENT)) + return r; + } + /* Warning, early returns above */ + return -EPERM; +} + +int LUKS_del_key(unsigned int keyIndex, + struct luks_phdr *hdr, + struct crypt_device *ctx) +{ + struct device *device = crypt_metadata_device(ctx); + unsigned int startOffset, endOffset; + int r; + + r = LUKS_read_phdr(hdr, 1, 0, ctx); + if (r) + return r; + + r = LUKS_keyslot_set(hdr, keyIndex, 0, ctx); + if (r) { + log_err(ctx, _("Key slot %d is invalid, please select keyslot between 0 and %d."), + keyIndex, LUKS_NUMKEYS - 1); + return r; + } + + /* secure deletion of key material */ + startOffset = hdr->keyblock[keyIndex].keyMaterialOffset; + endOffset = startOffset + AF_split_sectors(hdr->keyBytes, hdr->keyblock[keyIndex].stripes); + + r = crypt_wipe_device(ctx, device, CRYPT_WIPE_SPECIAL, startOffset * SECTOR_SIZE, + (endOffset - startOffset) * SECTOR_SIZE, + (endOffset - startOffset) * SECTOR_SIZE, NULL, NULL); + if (r) { + if (r == -EACCES) { + log_err(ctx, _("Cannot write to device %s, permission denied."), + device_path(device)); + r = -EINVAL; + } else + log_err(ctx, _("Cannot wipe device %s."), + device_path(device)); + return r; + } + + /* Wipe keyslot info */ + memset(&hdr->keyblock[keyIndex].passwordSalt, 0, LUKS_SALTSIZE); + hdr->keyblock[keyIndex].passwordIterations = 0; + + r = LUKS_write_phdr(hdr, ctx); + + return r; +} + +crypt_keyslot_info LUKS_keyslot_info(struct luks_phdr *hdr, int keyslot) +{ + int i; + + if(keyslot >= LUKS_NUMKEYS || keyslot < 0) + return CRYPT_SLOT_INVALID; + + if (hdr->keyblock[keyslot].active == LUKS_KEY_DISABLED) + return CRYPT_SLOT_INACTIVE; + + if (hdr->keyblock[keyslot].active != LUKS_KEY_ENABLED) + return CRYPT_SLOT_INVALID; + + for(i = 0; i < LUKS_NUMKEYS; i++) + if(i != keyslot && hdr->keyblock[i].active == LUKS_KEY_ENABLED) + return CRYPT_SLOT_ACTIVE; + + return CRYPT_SLOT_ACTIVE_LAST; +} + +int LUKS_keyslot_find_empty(struct luks_phdr *hdr) +{ + int i; + + for (i = 0; i < LUKS_NUMKEYS; i++) + if(hdr->keyblock[i].active == LUKS_KEY_DISABLED) + break; + + if (i == LUKS_NUMKEYS) + return -EINVAL; + + return i; +} + +int LUKS_keyslot_active_count(struct luks_phdr *hdr) +{ + int i, num = 0; + + for (i = 0; i < LUKS_NUMKEYS; i++) + if(hdr->keyblock[i].active == LUKS_KEY_ENABLED) + num++; + + return num; +} + +int LUKS_keyslot_set(struct luks_phdr *hdr, int keyslot, int enable, struct crypt_device *ctx) +{ + crypt_keyslot_info ki = LUKS_keyslot_info(hdr, keyslot); + + if (ki == CRYPT_SLOT_INVALID) + return -EINVAL; + + hdr->keyblock[keyslot].active = enable ? LUKS_KEY_ENABLED : LUKS_KEY_DISABLED; + log_dbg(ctx, "Key slot %d was %s in LUKS header.", keyslot, enable ? "enabled" : "disabled"); + return 0; +} + +int LUKS1_activate(struct crypt_device *cd, + const char *name, + struct volume_key *vk, + uint32_t flags) +{ + int r; + struct crypt_dm_active_device dmd = { + .flags = flags, + .uuid = crypt_get_uuid(cd), + }; + + r = dm_crypt_target_set(&dmd.segment, 0, dmd.size, crypt_data_device(cd), + vk, crypt_get_cipher_spec(cd), crypt_get_iv_offset(cd), + crypt_get_data_offset(cd), crypt_get_integrity(cd), + crypt_get_integrity_tag_size(cd), crypt_get_sector_size(cd)); + if (!r) + r = create_or_reload_device(cd, name, CRYPT_LUKS1, &dmd); + + dm_targets_free(cd, &dmd); + + return r; +} + +int LUKS_wipe_header_areas(struct luks_phdr *hdr, + struct crypt_device *ctx) +{ + int i, r; + uint64_t offset, length; + size_t wipe_block; + + /* Wipe complete header, keyslots and padding areas with zeroes. */ + offset = 0; + length = (uint64_t)hdr->payloadOffset * SECTOR_SIZE; + wipe_block = 1024 * 1024; + + /* On detached header or bogus header, wipe at least the first 4k */ + if (length == 0 || length > (LUKS_MAX_KEYSLOT_SIZE * LUKS_NUMKEYS)) { + length = 4096; + wipe_block = 4096; + } + + log_dbg(ctx, "Wiping LUKS areas (0x%06" PRIx64 " - 0x%06" PRIx64") with zeroes.", + offset, length + offset); + + r = crypt_wipe_device(ctx, crypt_metadata_device(ctx), CRYPT_WIPE_ZERO, + offset, length, wipe_block, NULL, NULL); + if (r < 0) + return r; + + /* Wipe keyslots areas */ + wipe_block = 1024 * 1024; + for (i = 0; i < LUKS_NUMKEYS; i++) { + r = LUKS_keyslot_area(hdr, i, &offset, &length); + if (r < 0) + return r; + + /* Ignore too big LUKS1 keyslots here */ + if (length > LUKS_MAX_KEYSLOT_SIZE || + offset > (LUKS_MAX_KEYSLOT_SIZE - length)) + continue; + + if (length == 0 || offset < 4096) + return -EINVAL; + + log_dbg(ctx, "Wiping keyslot %i area (0x%06" PRIx64 " - 0x%06" PRIx64") with random data.", + i, offset, length + offset); + + r = crypt_wipe_device(ctx, crypt_metadata_device(ctx), CRYPT_WIPE_RANDOM, + offset, length, wipe_block, NULL, NULL); + if (r < 0) + return r; + } + + return r; +} + +int LUKS_keyslot_pbkdf(struct luks_phdr *hdr, int keyslot, struct crypt_pbkdf_type *pbkdf) +{ + if (keyslot >= LUKS_NUMKEYS || keyslot < 0) + return -EINVAL; + + pbkdf->type = CRYPT_KDF_PBKDF2; + pbkdf->hash = hdr->hashSpec; + pbkdf->iterations = hdr->keyblock[keyslot].passwordIterations; + pbkdf->max_memory_kb = 0; + pbkdf->parallel_threads = 0; + pbkdf->time_ms = 0; + pbkdf->flags = 0; + return 0; +} |