[PATCH v2] crypto: arm64/sm4 - Fix possible crash in GCM cryption

[Tianjia Zhang]

When the cryption total length is zero, GCM cryption call
skcipher_walk_done() will cause an unexpected crash, so skip calling
this function to avoid possible crash when the GCM cryption length
is equal to zero.

Fixes: ae1b83c7d572 ("crypto: arm64/sm4 - add CE implementation for GCM mode")
Signed-off-by: Tianjia Zhang <tianjia.zhang@xxxxxxxxxxxxxxxxx>
---
 arch/arm64/crypto/sm4-ce-gcm-glue.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/crypto/sm4-ce-gcm-glue.c b/arch/arm64/crypto/sm4-ce-gcm-glue.c
index c450a2025ca9..29aa7470281d 100644
--- a/arch/arm64/crypto/sm4-ce-gcm-glue.c
+++ b/arch/arm64/crypto/sm4-ce-gcm-glue.c
@@ -178,6 +178,9 @@ static int gcm_crypt(struct aead_request *req, struct skcipher_walk *walk,
 
 		kernel_neon_end();
 
+		if (unlikely(!walk->nbytes))
+			break;
+
 		err = skcipher_walk_done(walk, tail);
 		if (err)
 			return err;
-- 
2.24.3 (Apple Git-128)