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, unsigned int stripes,
unsigned int alignPayload,
unsigned int alignOffset,
uint32_t iteration_time_ms,
uint64_t *PBKDF2_per_sec,
int detached_metadata_device,
struct crypt_device *ctx)
{
unsigned int i = 0, hdr_sectors = LUKS_device_sectors(vk->keylength);
size_t blocksPerStripeSet, currentSector;
int r;
uuid_t partitionUuid;
char luksMagic[] = LUKS_MAGIC;
/* For separate metadata device allow zero alignment */
if (alignPayload == 0 && !detached_metadata_device)
alignPayload = DEFAULT_DISK_ALIGNMENT / SECTOR_SIZE;
if (alignPayload && detached_metadata_device && alignPayload < hdr_sectors) {
log_err(ctx, _("Data offset for detached LUKS header must be "
"either 0 or higher than header size (%d sectors).\n"),
hdr_sectors);
return -EINVAL;
}
if (crypt_hmac_size(hashSpec) < LUKS_DIGESTSIZE) {
log_err(ctx, _("Requested LUKS hash %s is not supported.\n"), hashSpec);
return -EINVAL;
}
if (uuid && uuid_parse(uuid, partitionUuid) == -1) {
log_err(ctx, _("Wrong LUKS UUID format provided.\n"));
return -EINVAL;
}
if (!uuid)
uuid_generate(partitionUuid);
memset(header,0,sizeof(struct luks_phdr));
/* Set Magic */
memcpy(header->magic,luksMagic,LUKS_MAGIC_L);
header->version=1;
strncpy(header->cipherName,cipherName,LUKS_CIPHERNAME_L);
strncpy(header->cipherMode,cipherMode,LUKS_CIPHERMODE_L);
strncpy(header->hashSpec,hashSpec,LUKS_HASHSPEC_L);
header->keyBytes=vk->keylength;
LUKS_fix_header_compatible(header);
r = LUKS_check_cipher(header, ctx);
if (r < 0)
return r;
log_dbg("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.\n"));
return r;
}
r = crypt_benchmark_kdf(ctx, "pbkdf2", header->hashSpec,
"foo", 3, "bar", 3, PBKDF2_per_sec);
if (r < 0) {
log_err(ctx, _("Not compatible PBKDF2 options (using hash algorithm %s).\n"),
header->hashSpec);
return r;
}
/* Compute master key digest */
iteration_time_ms /= 8;
header->mkDigestIterations = at_least((uint32_t)(*PBKDF2_per_sec/1024) * iteration_time_ms,
LUKS_MKD_ITERATIONS_MIN);
r = crypt_pbkdf("pbkdf2", header->hashSpec, vk->key,vk->keylength,
header->mkDigestSalt, LUKS_SALTSIZE,
header->mkDigest,LUKS_DIGESTSIZE,
header->mkDigestIterations);
if(r < 0) {
log_err(ctx, _("Cannot create LUKS header: header digest failed (using hash %s).\n"),
header->hashSpec);
return r;
}
currentSector = LUKS_ALIGN_KEYSLOTS / SECTOR_SIZE;
blocksPerStripeSet = AF_split_sectors(vk->keylength, stripes);
for(i = 0; i < LUKS_NUMKEYS; ++i) {
header->keyblock[i].active = LUKS_KEY_DISABLED;
header->keyblock[i].keyMaterialOffset = currentSector;
header->keyblock[i].stripes = stripes;
currentSector = size_round_up(currentSector + blocksPerStripeSet,
LUKS_ALIGN_KEYSLOTS / SECTOR_SIZE);
}
if (detached_metadata_device) {
/* for separate metadata device use alignPayload directly */
header->payloadOffset = alignPayload;
} else {
/* alignOffset - offset from natural device alignment provided by topology info */
currentSector = size_round_up(currentSector, alignPayload);
header->payloadOffset = currentSector + alignOffset;
}
uuid_unparse(partitionUuid, header->uuid);
log_dbg("Data offset %d, UUID %s, digest iterations %" PRIu32,
header->payloadOffset, header->uuid, header->mkDigestIterations);
return 0;
}
/* 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("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, LUKS_STRIPES,
phdr->payloadOffset, 0,
1, ctx);
if (r < 0)
goto out;
for(i = 0; i < LUKS_NUMKEYS; ++i) {
if (phdr->keyblock[i].active == LUKS_KEY_ENABLED) {
log_dbg("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;
}