crypto: sha1_generic - Add export/import support

This patch adds export/import support to sha1_generic.  The exported
type is defined by struct sha1_state, which is basically the entire
descriptor state of sha1_generic.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/sha1_generic.c

@@ -25,31 +25,21 @@
 #include <crypto/sha.h>
 #include <asm/byteorder.h>
 
-struct sha1_ctx {
-        u64 count;
-        u32 state[5];
-        u8 buffer[64];
-};
-
 static int sha1_init(struct shash_desc *desc)
 {
-	struct sha1_ctx *sctx = shash_desc_ctx(desc);
+	struct sha1_state *sctx = shash_desc_ctx(desc);
 
-	static const struct sha1_ctx initstate = {
-	  0,
-	  { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 },
-	  { 0, }
+	*sctx = (struct sha1_state){
+		.state = { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 },
 	};
 
-	*sctx = initstate;
-
 	return 0;
 }
 
 static int sha1_update(struct shash_desc *desc, const u8 *data,
 			unsigned int len)
 {
-	struct sha1_ctx *sctx = shash_desc_ctx(desc);
+	struct sha1_state *sctx = shash_desc_ctx(desc);
 	unsigned int partial, done;
 	const u8 *src;
 
@@ -85,7 +75,7 @@ static int sha1_update(struct shash_desc *desc, const u8 *data,
 /* Add padding and return the message digest. */
 static int sha1_final(struct shash_desc *desc, u8 *out)
 {
-	struct sha1_ctx *sctx = shash_desc_ctx(desc);
+	struct sha1_state *sctx = shash_desc_ctx(desc);
 	__be32 *dst = (__be32 *)out;
 	u32 i, index, padlen;
 	__be64 bits;
@@ -111,12 +101,31 @@ static int sha1_final(struct shash_desc *desc, u8 *out)
 	return 0;
 }
 
+static int sha1_export(struct shash_desc *desc, void *out)
+{
+	struct sha1_state *sctx = shash_desc_ctx(desc);
+
+	memcpy(out, sctx, sizeof(*sctx));
+	return 0;
+}
+
+static int sha1_import(struct shash_desc *desc, const void *in)
+{
+	struct sha1_state *sctx = shash_desc_ctx(desc);
+
+	memcpy(sctx, in, sizeof(*sctx));
+	return 0;
+}
+
 static struct shash_alg alg = {
 	.digestsize	=	SHA1_DIGEST_SIZE,
 	.init		=	sha1_init,
 	.update		=	sha1_update,
 	.final		=	sha1_final,
-	.descsize	=	sizeof(struct sha1_ctx),
+	.export		=	sha1_export,
+	.import		=	sha1_import,
+	.descsize	=	sizeof(struct sha1_state),
+	.statesize	=	sizeof(struct sha1_state),
 	.base		=	{
 		.cra_name	=	"sha1",
 		.cra_driver_name=	"sha1-generic",

include/crypto/sha.h

@@ -5,6 +5,8 @@
 #ifndef _CRYPTO_SHA_H
 #define _CRYPTO_SHA_H
 
+#include <linux/types.h>
+
 #define SHA1_DIGEST_SIZE        20
 #define SHA1_BLOCK_SIZE         64
 
@@ -62,4 +64,10 @@
 #define SHA512_H6	0x1f83d9abfb41bd6bULL
 #define SHA512_H7	0x5be0cd19137e2179ULL
 
+struct sha1_state {
+	u64 count;
+	u32 state[SHA1_DIGEST_SIZE / 4];
+	u8 buffer[SHA1_BLOCK_SIZE];
+};
+
 #endif