[PATCH v2 09/12] crypto: caam/qi2 - add xts check for block length equal to zero

[Andrei Botila]

From: Andrei Botila <andrei.botila@xxxxxxx>

XTS should not return succes when dealing with block length equal to zero.
This is different than the rest of the skcipher algorithms.

Fixes: 31bb2f0da1b50 ("crypto: caam - check zero-length input")
Cc: <stable@xxxxxxxxxxxxxxx> # v5.4+
Signed-off-by: Andrei Botila <andrei.botila@xxxxxxx>
---
 drivers/crypto/caam/caamalg_qi2.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/caam/caamalg_qi2.c b/drivers/crypto/caam/caamalg_qi2.c
index 5d2e554774c9..592f4a0344ff 100644
--- a/drivers/crypto/caam/caamalg_qi2.c
+++ b/drivers/crypto/caam/caamalg_qi2.c
@@ -1475,7 +1475,12 @@ static int skcipher_encrypt(struct skcipher_request *req)
 	struct caam_request *caam_req = skcipher_request_ctx(req);
 	int ret;
 
-	if (!req->cryptlen)
+	/*
+	 * XTS is expected to return an error even for input length = 0
+	 * Note that the case input length < block size will be caught during
+	 * HW offloading and return an error.
+	 */
+	if (!req->cryptlen && !ctx->fallback)
 		return 0;
 
 	if (ctx->fallback && (xts_skcipher_ivsize(req) ||
@@ -1519,7 +1524,12 @@ static int skcipher_decrypt(struct skcipher_request *req)
 	struct caam_request *caam_req = skcipher_request_ctx(req);
 	int ret;
 
-	if (!req->cryptlen)
+	/*
+	 * XTS is expected to return an error even for input length = 0
+	 * Note that the case input length < block size will be caught during
+	 * HW offloading and return an error.
+	 */
+	if (!req->cryptlen && !ctx->fallback)
 		return 0;
 
 	if (ctx->fallback && (xts_skcipher_ivsize(req) ||
-- 
2.17.1