[PATCH v3 07/10] crypto: caam - add xts check for block length equal to zero

[Andrei Botila]

From: Andrei Botila <andrei.bot...@nxp.com>

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: <sta...@vger.kernel.org> # v5.4+
Signed-off-by: Andrei Botila <andrei.bot...@nxp.com>
---
 drivers/crypto/caam/caamalg.c     |  7 ++++++-
 drivers/crypto/caam/caamalg_qi.c  |  7 ++++++-
 drivers/crypto/caam/caamalg_qi2.c | 14 ++++++++++++--
 3 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/drivers/crypto/caam/caamalg.c b/drivers/crypto/caam/caamalg.c
index a79b26f84169..e72aa3e2e065 100644
--- a/drivers/crypto/caam/caamalg.c
+++ b/drivers/crypto/caam/caamalg.c
@@ -1787,7 +1787,12 @@ static inline int skcipher_crypt(struct skcipher_request 
*req, bool encrypt)
        u32 *desc;
        int ret = 0;
 
-       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) ||
diff --git a/drivers/crypto/caam/caamalg_qi.c b/drivers/crypto/caam/caamalg_qi.c
index 30aceaf325d7..efcc7cb050fc 100644
--- a/drivers/crypto/caam/caamalg_qi.c
+++ b/drivers/crypto/caam/caamalg_qi.c
@@ -1405,7 +1405,12 @@ static inline int skcipher_crypt(struct skcipher_request 
*req, bool encrypt)
        struct caam_ctx *ctx = crypto_skcipher_ctx(skcipher);
        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) ||
diff --git a/drivers/crypto/caam/caamalg_qi2.c 
b/drivers/crypto/caam/caamalg_qi2.c
index 255b818c82b2..4cbd7e834888 100644
--- a/drivers/crypto/caam/caamalg_qi2.c
+++ b/drivers/crypto/caam/caamalg_qi2.c
@@ -1472,7 +1472,12 @@ 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) ||
@@ -1516,7 +1521,12 @@ 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