[RFC PATCH] crypto: skcipher - perform len fits into blocksize check at the top

[Christian Lamparter <chunkeey@gmail.com>]

This patch adds early check to test the given data length
is aligned with the supported ciphers blocksize, or abort
with -EINVAL in case the supplied chunk size does not fit
without padding into the blocksize for block ciphers.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

---

This will also work instead of the
"crypto: crypto4xx - blockciphers should only accept complete blocks"
It will fix all potential driver issues in other drivers as well as
break the drivers that don't have the correct blocksize set. it will
also make the extra checks scattered around in the drivers make
redundand as well as the extra tests that do send incomplete blocks
to the hardware drivers.
---
 include/crypto/skcipher.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/crypto/skcipher.h b/include/crypto/skcipher.h
index e555294ed77f..971294602a41 100644
--- a/include/crypto/skcipher.h
+++ b/include/crypto/skcipher.h
@@ -494,6 +494,8 @@ static inline int crypto_skcipher_encrypt(struct skcipher_request *req)
 	crypto_stats_get(alg);
 	if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 		ret = -ENOKEY;
+	else if (!IS_ALIGNED(cryptlen, crypto_skcipher_blocksize(tfm)))
+		ret = -EINVAL;
 	else
 		ret = tfm->encrypt(req);
 	crypto_stats_skcipher_encrypt(cryptlen, ret, alg);
@@ -521,6 +523,8 @@ static inline int crypto_skcipher_decrypt(struct skcipher_request *req)
 	crypto_stats_get(alg);
 	if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 		ret = -ENOKEY;
+	else if (!IS_ALIGNED(cryptlen, crypto_skcipher_blocksize(tfm)))
+		ret = -EINVAL;
 	else
 		ret = tfm->decrypt(req);
 	crypto_stats_skcipher_decrypt(cryptlen, ret, alg);
-- 
2.20.1