crypto: skcipher - Add separate walker for AEAD decryption
The AEAD decrypt interface includes the authentication tag in
req->cryptlen. Therefore we need to exlucde that when doing
a walk over it.
This patch adds separate walker functions for AEAD encryption
and decryption.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
diff --git a/crypto/skcipher.c b/crypto/skcipher.c
index 5367f81..aca07c6 100644
--- a/crypto/skcipher.c
+++ b/crypto/skcipher.c
@@ -500,8 +500,8 @@ int skcipher_walk_async(struct skcipher_walk *walk,
}
EXPORT_SYMBOL_GPL(skcipher_walk_async);
-int skcipher_walk_aead(struct skcipher_walk *walk, struct aead_request *req,
- bool atomic)
+static int skcipher_walk_aead_common(struct skcipher_walk *walk,
+ struct aead_request *req, bool atomic)
{
struct crypto_aead *tfm = crypto_aead_reqtfm(req);
int err;
@@ -514,7 +514,6 @@ int skcipher_walk_aead(struct skcipher_walk *walk, struct aead_request *req,
scatterwalk_copychunks(NULL, &walk->in, req->assoclen, 2);
scatterwalk_copychunks(NULL, &walk->out, req->assoclen, 2);
- walk->total = req->cryptlen;
walk->iv = req->iv;
walk->oiv = req->iv;
@@ -535,8 +534,36 @@ int skcipher_walk_aead(struct skcipher_walk *walk, struct aead_request *req,
return err;
}
+
+int skcipher_walk_aead(struct skcipher_walk *walk, struct aead_request *req,
+ bool atomic)
+{
+ walk->total = req->cryptlen;
+
+ return skcipher_walk_aead_common(walk, req, atomic);
+}
EXPORT_SYMBOL_GPL(skcipher_walk_aead);
+int skcipher_walk_aead_encrypt(struct skcipher_walk *walk,
+ struct aead_request *req, bool atomic)
+{
+ walk->total = req->cryptlen;
+
+ return skcipher_walk_aead_common(walk, req, atomic);
+}
+EXPORT_SYMBOL_GPL(skcipher_walk_aead_encrypt);
+
+int skcipher_walk_aead_decrypt(struct skcipher_walk *walk,
+ struct aead_request *req, bool atomic)
+{
+ struct crypto_aead *tfm = crypto_aead_reqtfm(req);
+
+ walk->total = req->cryptlen - crypto_aead_authsize(tfm);
+
+ return skcipher_walk_aead_common(walk, req, atomic);
+}
+EXPORT_SYMBOL_GPL(skcipher_walk_aead_decrypt);
+
static unsigned int crypto_skcipher_extsize(struct crypto_alg *alg)
{
if (alg->cra_type == &crypto_blkcipher_type)
