crypto: caam - properly set IV after {en,de}crypt

Certain cipher modes like CTS expect the IV (req->info) of
ablkcipher_request (or equivalently req->iv of skcipher_request) to
contain the last ciphertext block when the {en,de}crypt operation is done.
This is currently not the case for the CAAM driver which in turn breaks
e.g. cts(cbc(aes)) when the CAAM driver is enabled.

This patch fixes the CAAM driver to properly set the IV after the
{en,de}crypt operation of ablkcipher finishes.

This issue was revealed by the changes in the SW CTS mode in commit
0605c41cc53ca ("crypto: cts - Convert to skcipher")

Cc: <stable@vger.kernel.org> # 4.8+
Signed-off-by: David Gstir <david@sigma-star.at>
Reviewed-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/caam/caamalg.c b/drivers/crypto/caam/caamalg.c
index fde399c887798458e62270957cfca001237fdf72..0488b7f81dcf314ae0b9c37acf8ffd65efeb1c29 100644 (file)
--- a/drivers/crypto/caam/caamalg.c
+++ b/drivers/crypto/caam/caamalg.c
@@ -882,10 +882,10 @@ static void ablkcipher_encrypt_done(struct device *jrdev, u32 *desc, u32 err,
 {
        struct ablkcipher_request *req = context;
        struct ablkcipher_edesc *edesc;
-#ifdef DEBUG
        struct crypto_ablkcipher *ablkcipher = crypto_ablkcipher_reqtfm(req);
        int ivsize = crypto_ablkcipher_ivsize(ablkcipher);
 
+#ifdef DEBUG
        dev_err(jrdev, "%s %d: err 0x%x\n", __func__, __LINE__, err);
 #endif
 
@@ -904,6 +904,14 @@ static void ablkcipher_encrypt_done(struct device *jrdev, u32 *desc, u32 err,
 #endif
 
        ablkcipher_unmap(jrdev, edesc, req);
+
+       /*
+        * The crypto API expects us to set the IV (req->info) to the last
+        * ciphertext block. This is used e.g. by the CTS mode.
+        */
+       scatterwalk_map_and_copy(req->info, req->dst, req->nbytes - ivsize,
+                                ivsize, 0);
+
        kfree(edesc);
 
        ablkcipher_request_complete(req, err);
@@ -914,10 +922,10 @@ static void ablkcipher_decrypt_done(struct device *jrdev, u32 *desc, u32 err,
 {
        struct ablkcipher_request *req = context;
        struct ablkcipher_edesc *edesc;
-#ifdef DEBUG
        struct crypto_ablkcipher *ablkcipher = crypto_ablkcipher_reqtfm(req);
        int ivsize = crypto_ablkcipher_ivsize(ablkcipher);
 
+#ifdef DEBUG
        dev_err(jrdev, "%s %d: err 0x%x\n", __func__, __LINE__, err);
 #endif
 
@@ -935,6 +943,14 @@ static void ablkcipher_decrypt_done(struct device *jrdev, u32 *desc, u32 err,
 #endif
 
        ablkcipher_unmap(jrdev, edesc, req);
+
+       /*
+        * The crypto API expects us to set the IV (req->info) to the last
+        * ciphertext block.
+        */
+       scatterwalk_map_and_copy(req->info, req->src, req->nbytes - ivsize,
+                                ivsize, 0);
+
        kfree(edesc);
 
        ablkcipher_request_complete(req, err);