crypto: padlock-sha - Add import/export support

As the padlock driver for SHA uses a software fallback to perform
partial hashing, it must implement custom import/export functions.
Otherwise hmac which depends on import/export for prehashing will
not work with padlock-sha.
Reported-by: Wolfgang Walter <wolfgang.walter@stwm.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/padlock-sha.c

@@ -57,6 +57,23 @@ static int padlock_sha_update(struct shash_desc *desc,
 	return crypto_shash_update(&dctx->fallback, data, length);
 }
 
+static int padlock_sha_export(struct shash_desc *desc, void *out)
+{
+	struct padlock_sha_desc *dctx = shash_desc_ctx(desc);
+
+	return crypto_shash_export(&dctx->fallback, out);
+}
+
+static int padlock_sha_import(struct shash_desc *desc, const void *in)
+{
+	struct padlock_sha_desc *dctx = shash_desc_ctx(desc);
+	struct padlock_sha_ctx *ctx = crypto_shash_ctx(desc->tfm);
+
+	dctx->fallback.tfm = ctx->fallback;
+	dctx->fallback.flags = desc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
+	return crypto_shash_import(&dctx->fallback, in);
+}
+
 static inline void padlock_output_block(uint32_t *src,
 		 	uint32_t *dst, size_t count)
 {
@@ -235,7 +252,10 @@ static struct shash_alg sha1_alg = {
 	.update 	=	padlock_sha_update,
 	.finup  	=	padlock_sha1_finup,
 	.final  	=	padlock_sha1_final,
+	.export		=	padlock_sha_export,
+	.import		=	padlock_sha_import,
 	.descsize	=	sizeof(struct padlock_sha_desc),
+	.statesize	=	sizeof(struct sha1_state),
 	.base		=	{
 		.cra_name		=	"sha1",
 		.cra_driver_name	=	"sha1-padlock",
@@ -256,7 +276,10 @@ static struct shash_alg sha256_alg = {
 	.update 	=	padlock_sha_update,
 	.finup  	=	padlock_sha256_finup,
 	.final  	=	padlock_sha256_final,
+	.export		=	padlock_sha_export,
+	.import		=	padlock_sha_import,
 	.descsize	=	sizeof(struct padlock_sha_desc),
+	.statesize	=	sizeof(struct sha256_state),
 	.base		=	{
 		.cra_name		=	"sha256",
 		.cra_driver_name	=	"sha256-padlock",