[PATCH 09/22] crypto: xts - add check for block length equal to zero

[Andrei Botila]

From: Andrei Botila <andrei.botila at nxp.com>

Standardize the way input lengths equal to 0 are handled in all skcipher
algorithms. All the algorithms return 0 for input lengths equal to zero.

Signed-off-by: Andrei Botila <andrei.botila at nxp.com>
---
 crypto/xts.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/crypto/xts.c b/crypto/xts.c
index 3c3ed02c7663..7df68f52fddc 100644
--- a/crypto/xts.c
+++ b/crypto/xts.c
@@ -263,6 +263,9 @@ static int xts_encrypt(struct skcipher_request *req)
 	struct skcipher_request *subreq = &rctx->subreq;
 	int err;
 
+	if (!req->cryptlen)
+		return 0;
+
 	err = xts_init_crypt(req, xts_encrypt_done) ?:
 	      xts_xor_tweak_pre(req, true) ?:
 	      crypto_skcipher_encrypt(subreq) ?:
@@ -280,6 +283,9 @@ static int xts_decrypt(struct skcipher_request *req)
 	struct skcipher_request *subreq = &rctx->subreq;
 	int err;
 
+	if (!req->cryptlen)
+		return 0;
+
 	err = xts_init_crypt(req, xts_decrypt_done) ?:
 	      xts_xor_tweak_pre(req, false) ?:
 	      crypto_skcipher_decrypt(subreq) ?:
-- 
2.17.1