/*
* LUKS - Linux Unified Key Setup
*
* Copyright (C) 2004-2006 Clemens Fruhwirth <clemens@endorphin.org>
* Copyright (C) 2009-2020 Red Hat, Inc. All rights reserved.
* Copyright (C) 2013-2020 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 <sys/types.h>
#include <sys/stat.h>
#include <netinet/in.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 fd, devfd, r = 0;
size_t hdr_size;
size_t buffer_size;
ssize_t ret;
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_lseek_blockwise(devfd, device_block_size(ctx, device), device_alignment(device),
buffer, hdr_size, 0) < (ssize_t)hdr_size) {
r = -EIO;
goto out;
}
/* 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));
fd = open(backup_file, O_CREAT|O_EXCL|O_WRONLY, S_IRUSR);
if (fd == -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;
}
ret = write_buffer(fd, buffer, buffer_size);
close(fd);
if (ret < (ssize_t)buffer_size) {
log_err(ctx, _("Cannot write header backup file %s."), backup_file);
r = -EIO;
goto out;
}
r = 0;
out:
crypt_safe_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 fd, r = 0, devfd = -1, diff_uuid = 0;
ssize_t ret, 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 does not contain valid LUKS header."));
r = -EINVAL;
goto out;
}
buffer = crypt_safe_alloc(buffer_size);
if (!buffer) {
r = -ENOMEM;
goto out;
}
fd = open(backup_file, O_RDONLY);
if (fd == -1) {
log_err(ctx, _("Cannot open header backup file %s."), backup_file);
r = -EINVAL;
goto out;
}
ret = read_buffer(fd, buffer, buffer_size);
close(fd);
if (ret < buffer_size) {
log_err(ctx, _("Cannot read header backup file %s."), backup_file);
r = -EIO;
goto out;
}
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_lseek_blockwise(devfd, device_block_size(ctx, device), device_alignment(device),
buffer, buffer_size, 0) < buffer_size) {
r = -EIO;
goto out;
}
/* Be sure to reload new data */
r = LUKS_read_phdr(hdr, 1, 0, ctx);
out:
device_sync(ctx, device);
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_safe_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)
{
int devfd, r = 0;
struct device *device = crypt_metadata_device(ctx);
ssize_t hdr_size = sizeof(struct luks_phdr);
/* 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_lseek_blockwise(devfd, device_block_size(ctx, device), device_alignment(device),
hdr, hdr_size, 0) < 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);
}
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_lseek_blockwise(devfd, device_block_size(ctx, device), device_alignment(device),
&convHdr, hdr_size, 0) < 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);
/* 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_safe_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);
if (pbkdf->flags & CRYPT_PBKDF_NO_BENCHMARK && pbkdf->time_ms == 0)
PBKDF2_temp = LUKS_MKD_ITERATIONS_MIN;
else /* iterations per ms * LUKS_MKD_ITERATIONS_MS */
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);
assert(header->mkDigestIterations);
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) {
log_err(ctx, _("Cannot open keyslot (using hash %s)."), hdr->hashSpec);
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, tried = 0;
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;
if (r == -EPERM)
tried++;
}
/* Warning, early returns above */
return tried ? -EPERM : -ENOENT;
}
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 (LUKS_keyslot_info(hdr, keyslot) < CRYPT_SLOT_ACTIVE)
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;
}