crypto: allow blkcipher walks over AEAD data

This adds the function blkcipher_aead_walk_virt_block, which allows the caller
to use the blkcipher walk API to handle the input and output scatterlists.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

2 files changed, 18 insertions, 0 deletions

diff --git a/crypto/blkcipher.c b/crypto/blkcipher.c
index 46fdab5e9cc7..0122bec38564 100644
--- a/crypto/blkcipher.c
+++ b/crypto/blkcipher.c
@@ -357,6 +357,20 @@ int blkcipher_walk_virt_block(struct blkcipher_desc *desc,
 }
 EXPORT_SYMBOL_GPL(blkcipher_walk_virt_block);
 
+int blkcipher_aead_walk_virt_block(struct blkcipher_desc *desc,
+                                   struct blkcipher_walk *walk,
+                                   struct crypto_aead *tfm,
+                                   unsigned int blocksize)
+{
+        walk->flags &= ~BLKCIPHER_WALK_PHYS;
+        walk->walk_blocksize = blocksize;
+        walk->cipher_blocksize = crypto_aead_blocksize(tfm);
+        walk->ivsize = crypto_aead_ivsize(tfm);
+        walk->alignmask = crypto_aead_alignmask(tfm);
+        return blkcipher_walk_first(desc, walk);
+}
+EXPORT_SYMBOL_GPL(blkcipher_aead_walk_virt_block);
+
 static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key,
                             unsigned int keylen)
 {
diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h
index d9d14a0f0653..016c2f110f63 100644
--- a/include/crypto/algapi.h
+++ b/include/crypto/algapi.h
@@ -195,6 +195,10 @@ int blkcipher_walk_phys(struct blkcipher_desc *desc,
 int blkcipher_walk_virt_block(struct blkcipher_desc *desc,
                               struct blkcipher_walk *walk,
                               unsigned int blocksize);
+int blkcipher_aead_walk_virt_block(struct blkcipher_desc *desc,
+                                   struct blkcipher_walk *walk,
+                                   struct crypto_aead *tfm,
+                                   unsigned int blocksize);
 
 int ablkcipher_walk_done(struct ablkcipher_request *req,
                          struct ablkcipher_walk *walk, int err);