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Commit 7e3fd855 authored by Milan Broz's avatar Milan Broz Committed by Mike Snitzer
Browse files

dm crypt: add big-endian variant of plain64 IV 



The big-endian IV (plain64be) is needed to map images from extracted
disks that are used in some external (on-chip FDE) disk encryption
drives, e.g.: data recovery from external USB/SATA drives that support
"internal" encryption.

Signed-off-by: default avatarMilan Broz <gmazyland@gmail.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 6e333d0b

drivers/md/dm-crypt.c

+20 −1
Original line number Diff line number Diff line
@@ -246,6 +246,9 @@ static struct crypto_aead *any_tfm_aead(struct crypt_config *cc) 
 * plain64: the initial vector is the 64-bit little-endian version of the sector

 *        number, padded with zeros if necessary.

 *

 * plain64be: the initial vector is the 64-bit big-endian version of the sector

 *        number, padded with zeros if necessary.

 *

 * essiv: "encrypted sector|salt initial vector", the sector number is

 *        encrypted with the bulk cipher using a salt as key. The salt

 *        should be derived from the bulk cipher's key via hashing.
@@ -302,6 +305,16 @@ static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv, 
	return 0;

}



static int crypt_iv_plain64be_gen(struct crypt_config *cc, u8 *iv,

				  struct dm_crypt_request *dmreq)

{

	memset(iv, 0, cc->iv_size);

	/* iv_size is at least of size u64; usually it is 16 bytes */

	*(__be64 *)&iv[cc->iv_size - sizeof(u64)] = cpu_to_be64(dmreq->iv_sector);



	return 0;

}



/* Initialise ESSIV - compute salt but no local memory allocations */

static int crypt_iv_essiv_init(struct crypt_config *cc)

{
@@ -835,6 +848,10 @@ static const struct crypt_iv_operations crypt_iv_plain64_ops = { 
	.generator = crypt_iv_plain64_gen

};



static const struct crypt_iv_operations crypt_iv_plain64be_ops = {

	.generator = crypt_iv_plain64be_gen

};



static const struct crypt_iv_operations crypt_iv_essiv_ops = {

	.ctr       = crypt_iv_essiv_ctr,

	.dtr       = crypt_iv_essiv_dtr,
@@ -2208,6 +2225,8 @@ static int crypt_ctr_ivmode(struct dm_target *ti, const char *ivmode) 
		cc->iv_gen_ops = &crypt_iv_plain_ops;

	else if (strcmp(ivmode, "plain64") == 0)

		cc->iv_gen_ops = &crypt_iv_plain64_ops;

	else if (strcmp(ivmode, "plain64be") == 0)

		cc->iv_gen_ops = &crypt_iv_plain64be_ops;

	else if (strcmp(ivmode, "essiv") == 0)

		cc->iv_gen_ops = &crypt_iv_essiv_ops;

	else if (strcmp(ivmode, "benbi") == 0)
@@ -2987,7 +3006,7 @@ static void crypt_io_hints(struct dm_target *ti, struct queue_limits *limits) 


static struct target_type crypt_target = {

	.name   = "crypt",

	.version = {1, 17, 0},

	.version = {1, 18, 0},

	.module = THIS_MODULE,

	.ctr    = crypt_ctr,

	.dtr    = crypt_dtr,