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("LUKS header not detected.");
if (require_luks_device)
log_err(ctx, _("Device %s is not a valid LUKS device.\n"), 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.\n"), 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.\n"), 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_keyslot_size(hdr, i)) {
log_err(ctx, _("LUKS keyslot %u is invalid.\n"), i);
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.\n"));
}
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, 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;
}
int pkcs5_pbkdf2(const char *hash,
const char *P, size_t Plen,
const char *S, size_t Slen,
unsigned int c, unsigned int dkLen,
char *DK, unsigned int hash_block_size)
{
struct crypt_hmac *hmac;
char U[MAX_PRF_BLOCK_LEN];
char T[MAX_PRF_BLOCK_LEN];
char P_hash[MAX_PRF_BLOCK_LEN];
int i, k, rc = -EINVAL;
unsigned int u, hLen, l, r;
size_t tmplen = Slen + 4;
char *tmp;
tmp = alloca(tmplen);
if (tmp == NULL)
return -ENOMEM;
hLen = crypt_hmac_size(hash);
if (hLen == 0 || hLen > MAX_PRF_BLOCK_LEN)
return -EINVAL;
if (c == 0)
return -EINVAL;
if (dkLen == 0)
return -EINVAL;
/*
*
* Steps:
*
* 1. If dkLen > (2^32 - 1) * hLen, output "derived key too long" and
* stop.
*/
if (dkLen > 4294967295U)
return -EINVAL;
/*
* 2. Let l be the number of hLen-octet blocks in the derived key,
* rounding up, and let r be the number of octets in the last
* block:
*
* l = CEIL (dkLen / hLen) ,
* r = dkLen - (l - 1) * hLen .
*
* Here, CEIL (x) is the "ceiling" function, i.e. the smallest
* integer greater than, or equal to, x.
*/
l = dkLen / hLen;
if (dkLen % hLen)
l++;
r = dkLen - (l - 1) * hLen;
/*
* 3. For each block of the derived key apply the function F defined
* below to the password P, the salt S, the iteration count c, and
* the block index to compute the block:
*
* T_1 = F (P, S, c, 1) ,
* T_2 = F (P, S, c, 2) ,
* ...
* T_l = F (P, S, c, l) ,
*
* where the function F is defined as the exclusive-or sum of the
* first c iterates of the underlying pseudorandom function PRF
* applied to the password P and the concatenation of the salt S
* and the block index i:
*
* F (P, S, c, i) = U_1 \xor U_2 \xor ... \xor U_c
*
* where
*
* U_1 = PRF (P, S || INT (i)) ,
* U_2 = PRF (P, U_1) ,
* ...
* U_c = PRF (P, U_{c-1}) .
*
* Here, INT (i) is a four-octet encoding of the integer i, most
* significant octet first.
*
* 4. Concatenate the blocks and extract the first dkLen octets to
* produce a derived key DK:
*
* DK = T_1 || T_2 || ... || T_l<0..r-1>
*
* 5. Output the derived key DK.
*
* Note. The construction of the function F follows a "belt-and-
* suspenders" approach. The iterates U_i are computed recursively to
* remove a degree of parallelism from an opponent; they are exclusive-
* ored together to reduce concerns about the recursion degenerating
* into a small set of values.
*
*/
/* If hash_block_size is provided, hash password in advance. */
if (hash_block_size > 0 && Plen > hash_block_size) {
if (hash_buf(P, Plen, P_hash, hLen, hash))
return -EINVAL;
if (crypt_hmac_init(&hmac, hash, P_hash, hLen))
return -EINVAL;
memset(P_hash, 0, sizeof(P_hash));
} else {
if (crypt_hmac_init(&hmac, hash, P, Plen))
return -EINVAL;
}
for (i = 1; (unsigned int) i <= l; i++) {
memset(T, 0, hLen);
for (u = 1; u <= c ; u++) {
if (u == 1) {
memcpy(tmp, S, Slen);
tmp[Slen + 0] = (i & 0xff000000) >> 24;
tmp[Slen + 1] = (i & 0x00ff0000) >> 16;
tmp[Slen + 2] = (i & 0x0000ff00) >> 8;
tmp[Slen + 3] = (i & 0x000000ff) >> 0;
if (crypt_hmac_write(hmac, tmp, tmplen))
goto out;
} else {
if (crypt_hmac_write(hmac, U, hLen))
goto out;
}
if (crypt_hmac_final(hmac, U, hLen))
goto out;
for (k = 0; (unsigned int) k < hLen; k++)
T[k] ^= U[k];
}
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;
}
