Commit 28856a9e authored by Stephan Mueller's avatar Stephan Mueller Committed by Herbert Xu

crypto: xts - consolidate sanity check for keys

The patch centralizes the XTS key check logic into the service function
xts_check_key which is invoked from the different XTS implementations.
With this, the XTS implementations in ARM, ARM64, PPC and S390 have now
a sanity check for the XTS keys similar to the other arches.

In addition, this service function received a check to ensure that the
key != the tweak key which is mandated by FIPS 140-2 IG A.9. As the
check is not present in the standards defining XTS, it is only enforced
in FIPS mode of the kernel.
Signed-off-by: default avatarStephan Mueller <smueller@chronox.de>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 730d02e2
......@@ -152,6 +152,10 @@ static int xts_set_key(struct crypto_tfm *tfm, const u8 *in_key,
struct crypto_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
int ret;
ret = xts_check_key(tfm, in_key, key_len);
if (ret)
return ret;
ret = ce_aes_expandkey(&ctx->key1, in_key, key_len / 2);
if (!ret)
ret = ce_aes_expandkey(&ctx->key2, &in_key[key_len / 2],
......
......@@ -89,6 +89,11 @@ static int aesbs_xts_set_key(struct crypto_tfm *tfm, const u8 *in_key,
{
struct aesbs_xts_ctx *ctx = crypto_tfm_ctx(tfm);
int bits = key_len * 4;
int err;
err = xts_check_key(tfm, in_key, key_len);
if (err)
return err;
if (private_AES_set_encrypt_key(in_key, bits, &ctx->enc.rk)) {
tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
......
......@@ -85,6 +85,10 @@ static int xts_set_key(struct crypto_tfm *tfm, const u8 *in_key,
struct crypto_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
int ret;
ret = xts_check_key(tfm, in_key, key_len);
if (ret)
return ret;
ret = aes_expandkey(&ctx->key1, in_key, key_len / 2);
if (!ret)
ret = aes_expandkey(&ctx->key2, &in_key[key_len / 2],
......
......@@ -126,6 +126,11 @@ static int ppc_xts_setkey(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
struct ppc_xts_ctx *ctx = crypto_tfm_ctx(tfm);
int err;
err = xts_check_key(tfm, in_key, key_len);
if (err)
return err;
key_len >>= 1;
......
......@@ -587,6 +587,11 @@ static int xts_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
{
struct s390_xts_ctx *xts_ctx = crypto_tfm_ctx(tfm);
u32 *flags = &tfm->crt_flags;
int err;
err = xts_check_key(tfm, in_key, key_len);
if (err)
return err;
switch (key_len) {
case 32:
......
......@@ -639,16 +639,11 @@ static int xts_aesni_setkey(struct crypto_tfm *tfm, const u8 *key,
unsigned int keylen)
{
struct aesni_xts_ctx *ctx = crypto_tfm_ctx(tfm);
u32 *flags = &tfm->crt_flags;
int err;
/* key consists of keys of equal size concatenated, therefore
* the length must be even
*/
if (keylen % 2) {
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
err = xts_check_key(tfm, key, keylen);
if (err)
return err;
/* first half of xts-key is for crypt */
err = aes_set_key_common(tfm, ctx->raw_crypt_ctx, key, keylen / 2);
......
......@@ -1503,13 +1503,9 @@ int xts_camellia_setkey(struct crypto_tfm *tfm, const u8 *key,
u32 *flags = &tfm->crt_flags;
int err;
/* key consists of keys of equal size concatenated, therefore
* the length must be even
*/
if (keylen % 2) {
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
err = xts_check_key(tfm, key, keylen);
if (err)
return err;
/* first half of xts-key is for crypt */
err = __camellia_setkey(&ctx->crypt_ctx, key, keylen / 2, flags);
......
......@@ -329,13 +329,9 @@ static int xts_cast6_setkey(struct crypto_tfm *tfm, const u8 *key,
u32 *flags = &tfm->crt_flags;
int err;
/* key consists of keys of equal size concatenated, therefore
* the length must be even
*/
if (keylen % 2) {
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
err = xts_check_key(tfm, key, keylen);
if (err)
return err;
/* first half of xts-key is for crypt */
err = __cast6_setkey(&ctx->crypt_ctx, key, keylen / 2, flags);
......
......@@ -332,16 +332,11 @@ int xts_serpent_setkey(struct crypto_tfm *tfm, const u8 *key,
unsigned int keylen)
{
struct serpent_xts_ctx *ctx = crypto_tfm_ctx(tfm);
u32 *flags = &tfm->crt_flags;
int err;
/* key consists of keys of equal size concatenated, therefore
* the length must be even
*/
if (keylen % 2) {
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
err = xts_check_key(tfm, key, keylen);
if (err)
return err;
/* first half of xts-key is for crypt */
err = __serpent_setkey(&ctx->crypt_ctx, key, keylen / 2);
......
......@@ -309,16 +309,11 @@ static int xts_serpent_setkey(struct crypto_tfm *tfm, const u8 *key,
unsigned int keylen)
{
struct serpent_xts_ctx *ctx = crypto_tfm_ctx(tfm);
u32 *flags = &tfm->crt_flags;
int err;
/* key consists of keys of equal size concatenated, therefore
* the length must be even
*/
if (keylen % 2) {
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
err = xts_check_key(tfm, key, keylen);
if (err)
return err;
/* first half of xts-key is for crypt */
err = __serpent_setkey(&ctx->crypt_ctx, key, keylen / 2);
......
......@@ -277,13 +277,9 @@ int xts_twofish_setkey(struct crypto_tfm *tfm, const u8 *key,
u32 *flags = &tfm->crt_flags;
int err;
/* key consists of keys of equal size concatenated, therefore
* the length must be even
*/
if (keylen % 2) {
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
err = xts_check_key(tfm, key, keylen);
if (err)
return err;
/* first half of xts-key is for crypt */
err = __twofish_setkey(&ctx->crypt_ctx, key, keylen / 2, flags);
......
......@@ -35,16 +35,11 @@ static int setkey(struct crypto_tfm *parent, const u8 *key,
{
struct priv *ctx = crypto_tfm_ctx(parent);
struct crypto_cipher *child = ctx->tweak;
u32 *flags = &parent->crt_flags;
int err;
/* key consists of keys of equal size concatenated, therefore
* the length must be even */
if (keylen % 2) {
/* tell the user why there was an error */
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
err = xts_check_key(parent, key, keylen);
if (err)
return err;
/* we need two cipher instances: one to compute the initial 'tweak'
* by encrypting the IV (usually the 'plain' iv) and the other
......
......@@ -2,6 +2,9 @@
#define _CRYPTO_XTS_H
#include <crypto/b128ops.h>
#include <linux/crypto.h>
#include <crypto/algapi.h>
#include <linux/fips.h>
struct scatterlist;
struct blkcipher_desc;
......@@ -24,4 +27,28 @@ int xts_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
struct scatterlist *src, unsigned int nbytes,
struct xts_crypt_req *req);
static inline int xts_check_key(struct crypto_tfm *tfm,
const u8 *key, unsigned int keylen)
{
u32 *flags = &tfm->crt_flags;
/*
* key consists of keys of equal size concatenated, therefore
* the length must be even.
*/
if (keylen % 2) {
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
/* ensure that the AES and tweak key are not identical */
if (fips_enabled &&
!crypto_memneq(key, key + (keylen / 2), keylen / 2)) {
*flags |= CRYPTO_TFM_RES_WEAK_KEY;
return -EINVAL;
}
return 0;
}
#endif /* _CRYPTO_XTS_H */
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment