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;
}
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("Reading LUKS header of size %zu from device %s",
hdr_size, device_path(device));
devfd = device_open(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(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("Old unaligned LUKS keyslot detected, disabling direct-io.");
device_disable_direct_io(device);
}
close(devfd);
return r;
}
int LUKS2_hdr_version_unlocked(struct crypt_device *cd, const char *backup_file)
{
struct {
char magic[LUKS2_MAGIC_L];
uint16_t version;
} __attribute__ ((packed)) hdr;
struct device *device = NULL;
int r = 0, devfd = -1, flags;
if (!backup_file)
device = crypt_metadata_device(cd);
else if (device_alloc(&device, backup_file) < 0)
return 0;
if (!device)
return 0;
flags = O_RDONLY;
if (device_direct_io(device))
flags |= O_DIRECT;
devfd = open(device_path(device), flags);
if (devfd < 0)
goto err;
if ((read_lseek_blockwise(devfd, device_block_size(device),
device_alignment(device), &hdr, sizeof(hdr), 0) == sizeof(hdr)) &&
!memcmp(hdr.magic, LUKS2_MAGIC_1ST, LUKS2_MAGIC_L))
r = (int)be16_to_cpu(hdr.version);
err:
if (devfd != -1)
close(devfd);
if (backup_file)
device_free(device);
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("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("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(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(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)
close(devfd);
crypt_safe_free(buffer);
return r;
}
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("Storing backup of header (%zu bytes) and keyslot area (%zu bytes).",
sizeof(hdr), hdr_size - LUKS_ALIGN_KEYSLOTS);
log_dbg("Output backup file size: %zu bytes.", buffer_size);
devfd = device_open(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(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;
}
/*
* Write LUKS2 header to disk at specific offset.
*/
static int hdr_write_disk(struct device *device, struct luks2_hdr *hdr,
const char *json_area, int secondary)
{
struct luks2_hdr_disk hdr_disk;
uint64_t offset = secondary ? hdr->hdr_size : 0;
size_t hdr_json_len;
int devfd = -1, r;
log_dbg("Trying to write LUKS2 header (%zu bytes) at offset %" PRIu64 ".",
hdr->hdr_size, offset);
/* FIXME: read-only device silent fail? */
devfd = device_open_locked(device, O_RDWR);
if (devfd < 0)
return devfd == -1 ? -EINVAL : devfd;
hdr_json_len = hdr->hdr_size - LUKS2_HDR_BIN_LEN;
hdr_to_disk(hdr, &hdr_disk, secondary, offset);
/*
* Write header without checksum but with proper seqid.
*/
if (write_lseek_blockwise(devfd, device_block_size(device),
device_alignment(device), (char *)&hdr_disk,
LUKS2_HDR_BIN_LEN, offset) < (ssize_t)LUKS2_HDR_BIN_LEN) {
close(devfd);
return -EIO;
}
/*
* Write json area.
*/
if (write_lseek_blockwise(devfd, device_block_size(device),
device_alignment(device),
CONST_CAST(char*)json_area, hdr_json_len,
LUKS2_HDR_BIN_LEN + offset) < (ssize_t)hdr_json_len) {
close(devfd);
return -EIO;
}
/*
* Calculate checksum and write header with checksum.
*/
r = hdr_checksum_calculate(hdr_disk.checksum_alg, &hdr_disk,
json_area, hdr_json_len);
if (r < 0) {
close(devfd);
return r;
}
log_dbg_checksum(hdr_disk.csum, hdr_disk.checksum_alg, "in-memory");
if (write_lseek_blockwise(devfd, device_block_size(device),
device_alignment(device), (char *)&hdr_disk,
LUKS2_HDR_BIN_LEN, offset) < (ssize_t)LUKS2_HDR_BIN_LEN)
r = -EIO;
close(devfd);
return r;
}
/*
* Read LUKS2 header from disk at specific offset.
*/
static int hdr_read_disk(struct device *device, struct luks2_hdr_disk *hdr_disk,
char **json_area, uint64_t offset, int secondary)
{
size_t hdr_json_size = 0;
int devfd = -1, r;
log_dbg("Trying to read %s LUKS2 header at offset %" PRIu64 ".",
secondary ? "secondary" : "primary", offset);
devfd = device_open_locked(device, O_RDONLY);
if (devfd < 0)
return devfd == -1 ? -EIO : devfd;
/*
* Read binary header and run sanity check before reading
* JSON area and validating checksum.
*/
if (read_lseek_blockwise(devfd, device_block_size(device),
device_alignment(device), hdr_disk,
LUKS2_HDR_BIN_LEN, offset) != LUKS2_HDR_BIN_LEN) {
close(devfd);
return -EIO;
}
r = hdr_disk_sanity_check_pre(hdr_disk, &hdr_json_size, secondary, offset);
if (r < 0) {
close(devfd);
return r;
}
/*
* Allocate and read JSON area. Always the whole area must be read.
*/
*json_area = malloc(hdr_json_size);
if (!*json_area) {
close(devfd);
return -ENOMEM;
}
if (read_lseek_blockwise(devfd, device_block_size(device),
device_alignment(device), *json_area, hdr_json_size,
offset + LUKS2_HDR_BIN_LEN) != (ssize_t)hdr_json_size) {
close(devfd);
free(*json_area);
*json_area = NULL;
return -EIO;
}
close(devfd);
/*
* Calculate and validate checksum and zero it afterwards.
*/
if (hdr_checksum_check(hdr_disk->checksum_alg, hdr_disk,
*json_area, hdr_json_size)) {
log_dbg("LUKS2 header checksum error (offset %" PRIu64 ").", offset);
r = -EINVAL;
}
memset(hdr_disk->csum, 0, LUKS2_CHECKSUM_L);
return r;
}
