Hi Stephan,
On 7 February 2016 at 14:05, Stephan Mueller <smueller@xxxxxxxxxx> wrote:
> Hi,
>
> I only have an x86 system for testing. May I ask the owners for the other architectures to review and test?
>
> ---8<---
>
> 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@xxxxxxxxxx>
One remark below (and a nit). With that fixed:
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> ---
> arch/arm/crypto/aes-ce-glue.c | 4 ++++
> arch/arm/crypto/aesbs-glue.c | 5 +++++
> arch/arm64/crypto/aes-glue.c | 4 ++++
> arch/powerpc/crypto/aes-spe-glue.c | 5 +++++
> arch/s390/crypto/aes_s390.c | 5 +++++
> arch/x86/crypto/aesni-intel_glue.c | 11 +++--------
> arch/x86/crypto/camellia_glue.c | 10 +++-------
> arch/x86/crypto/cast6_avx_glue.c | 10 +++-------
> arch/x86/crypto/serpent_avx_glue.c | 11 +++--------
> arch/x86/crypto/serpent_sse2_glue.c | 11 +++--------
> arch/x86/crypto/twofish_glue_3way.c | 10 +++-------
> crypto/xts.c | 11 +++--------
> include/crypto/xts.h | 29 +++++++++++++++++++++++++++++
> 13 files changed, 73 insertions(+), 53 deletions(-)
>
> diff --git a/arch/arm/crypto/aes-ce-glue.c b/arch/arm/crypto/aes-ce-glue.c
> index b445a5d..85ff69b 100644
> --- a/arch/arm/crypto/aes-ce-glue.c
> +++ b/arch/arm/crypto/aes-ce-glue.c
> @@ -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],
> diff --git a/arch/arm/crypto/aesbs-glue.c b/arch/arm/crypto/aesbs-glue.c
> index 6d68529..d004bd1 100644
> --- a/arch/arm/crypto/aesbs-glue.c
> +++ b/arch/arm/crypto/aesbs-glue.c
> @@ -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;
> diff --git a/arch/arm64/crypto/aes-glue.c b/arch/arm64/crypto/aes-glue.c
> index 05d9e16..c963d75 100644
> --- a/arch/arm64/crypto/aes-glue.c
> +++ b/arch/arm64/crypto/aes-glue.c
> @@ -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],
> diff --git a/arch/powerpc/crypto/aes-spe-glue.c b/arch/powerpc/crypto/aes-spe-glue.c
> index 93ee046..1608079 100644
> --- a/arch/powerpc/crypto/aes-spe-glue.c
> +++ b/arch/powerpc/crypto/aes-spe-glue.c
> @@ -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;
>
> diff --git a/arch/s390/crypto/aes_s390.c b/arch/s390/crypto/aes_s390.c
> index 0b9b95f..3f1a1a4 100644
> --- a/arch/s390/crypto/aes_s390.c
> +++ b/arch/s390/crypto/aes_s390.c
> @@ -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:
> diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
> index 3633ad6..064c7e2 100644
> --- a/arch/x86/crypto/aesni-intel_glue.c
> +++ b/arch/x86/crypto/aesni-intel_glue.c
> @@ -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);
> diff --git a/arch/x86/crypto/camellia_glue.c b/arch/x86/crypto/camellia_glue.c
> index 5c8b626..aa76cad 100644
> --- a/arch/x86/crypto/camellia_glue.c
> +++ b/arch/x86/crypto/camellia_glue.c
> @@ -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);
> diff --git a/arch/x86/crypto/cast6_avx_glue.c b/arch/x86/crypto/cast6_avx_glue.c
> index fca4595..50e6847 100644
> --- a/arch/x86/crypto/cast6_avx_glue.c
> +++ b/arch/x86/crypto/cast6_avx_glue.c
> @@ -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);
> diff --git a/arch/x86/crypto/serpent_avx_glue.c b/arch/x86/crypto/serpent_avx_glue.c
> index 5dc3702..6f778d3 100644
> --- a/arch/x86/crypto/serpent_avx_glue.c
> +++ b/arch/x86/crypto/serpent_avx_glue.c
> @@ -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);
> diff --git a/arch/x86/crypto/serpent_sse2_glue.c b/arch/x86/crypto/serpent_sse2_glue.c
> index 3643dd5..8943407 100644
> --- a/arch/x86/crypto/serpent_sse2_glue.c
> +++ b/arch/x86/crypto/serpent_sse2_glue.c
> @@ -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);
> diff --git a/arch/x86/crypto/twofish_glue_3way.c b/arch/x86/crypto/twofish_glue_3way.c
> index 56d8a08..2ebb5e9 100644
> --- a/arch/x86/crypto/twofish_glue_3way.c
> +++ b/arch/x86/crypto/twofish_glue_3way.c
> @@ -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);
> diff --git a/crypto/xts.c b/crypto/xts.c
> index f6fd43f..26ba583 100644
> --- a/crypto/xts.c
> +++ b/crypto/xts.c
> @@ -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
> diff --git a/include/crypto/xts.h b/include/crypto/xts.h
> index 72c09eb..41d936e 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 +27,30 @@ 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) {
> + /* tell the user why there was an error */
Nit: I don't think this comment adds anything useful tbh
> + *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
> + return -EINVAL;
> + }
> +
> +#ifdef CONFIG_CRYPTO_FIPS
> + /* ensure that the AES and tweak key are not identical */
> + if (fips_enabled &&
This is redundant. 'fips_enabled' is #defined to 0 if CRYPTO_FIPS=n so
you can lose the #ifdef entirely.
> + !crypto_memneq(key, key + (keylen / 2), keylen / 2)) {
> + *flags |= CRYPTO_TFM_RES_WEAK_KEY;
> + return -EINVAL;
> + }
> +#endif
> + return 0;
> +}
> +
> #endif /* _CRYPTO_XTS_H */
> --
> 2.5.0
>
>
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