[PATCH v3 06/10] crypto: caam/qi2 - add support for more XTS key lengths

[Andrei Botila]

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

CAAM accelerator only supports XTS-AES-128 and XTS-AES-256 since
it adheres strictly to the standard. All the other key lengths
are accepted and processed through a fallback as long as they pass
the xts_verify_key() checks.

Fixes: 226853ac3ebe ("crypto: caam/qi2 - add skcipher algorithms")
Cc: <sta...@vger.kernel.org> # v4.20+
Signed-off-by: Andrei Botila <andrei.bot...@nxp.com>
---
 drivers/crypto/caam/caamalg_qi2.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/crypto/caam/caamalg_qi2.c 
b/drivers/crypto/caam/caamalg_qi2.c
index c36d11820db3..255b818c82b2 100644
--- a/drivers/crypto/caam/caamalg_qi2.c
+++ b/drivers/crypto/caam/caamalg_qi2.c
@@ -19,6 +19,7 @@
 #include <linux/fsl/mc.h>
 #include <soc/fsl/dpaa2-io.h>
 #include <soc/fsl/dpaa2-fd.h>
+#include <crypto/xts.h>
 #include <asm/unaligned.h>
 
 #define CAAM_CRA_PRIORITY      2000
@@ -81,6 +82,7 @@ struct caam_ctx {
        struct alginfo adata;
        struct alginfo cdata;
        unsigned int authsize;
+       bool xts_key_fallback;
        struct crypto_skcipher *fallback;
 };
 
@@ -1060,11 +1062,15 @@ static int xts_skcipher_setkey(struct crypto_skcipher 
*skcipher, const u8 *key,
        u32 *desc;
        int err;
 
-       if (keylen != 2 * AES_MIN_KEY_SIZE  && keylen != 2 * AES_MAX_KEY_SIZE) {
+       err = xts_verify_key(skcipher, key, keylen);
+       if (err) {
                dev_dbg(dev, "key size mismatch\n");
-               return -EINVAL;
+               return err;
        }
 
+       if (keylen != 2 * AES_KEYSIZE_128 && keylen != 2 * AES_KEYSIZE_256)
+               ctx->xts_key_fallback = true;
+
        err = crypto_skcipher_setkey(ctx->fallback, key, keylen);
        if (err)
                return err;
@@ -1469,7 +1475,8 @@ static int skcipher_encrypt(struct skcipher_request *req)
        if (!req->cryptlen)
                return 0;
 
-       if (ctx->fallback && xts_skcipher_ivsize(req)) {
+       if (ctx->fallback && (xts_skcipher_ivsize(req) ||
+                             ctx->xts_key_fallback)) {
                skcipher_request_set_tfm(&caam_req->fallback_req, 
ctx->fallback);
                skcipher_request_set_callback(&caam_req->fallback_req,
                                              req->base.flags,
@@ -1512,7 +1519,8 @@ static int skcipher_decrypt(struct skcipher_request *req)
        if (!req->cryptlen)
                return 0;
 
-       if (ctx->fallback && xts_skcipher_ivsize(req)) {
+       if (ctx->fallback && (xts_skcipher_ivsize(req) ||
+                             ctx->xts_key_fallback)) {
                skcipher_request_set_tfm(&caam_req->fallback_req, 
ctx->fallback);
                skcipher_request_set_callback(&caam_req->fallback_req,
                                              req->base.flags,
-- 
2.17.1