diff options
| author | Stephan Mueller <smueller@chronox.de> | 2016-02-09 15:37:47 +0100 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2016-02-17 04:07:51 +0800 |
| commit | 28856a9e52c7cac712af6c143de04766617535dc (patch) | |
| tree | 4ee6c79e76f8eadc0148bfeb09fd146c9d53fabf /include/crypto | |
| parent | 730d02e27670fa5b6a55778d11023c5897d87d57 (diff) | |
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: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'include/crypto')
| -rw-r--r-- | include/crypto/xts.h | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/include/crypto/xts.h b/include/crypto/xts.h index 72c09eb56437..ede6b97b24cc 100644 --- a/include/crypto/xts.h +++ b/include/crypto/xts.h @@ -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 */ |