Hi,
Changes v2: remove comment and remove FIPS ifdefs as requested by Ard
Biesheuvel
---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>
---
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 | 27 +++++++++++++++++++++++++++
13 files changed, 71 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..ede6b97 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 */
--
2.5.0
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