crypto: hash - Fix clone error handling

Do not copy the exit function in crypto_clone_tfm as it should
only be set after init_tfm or clone_tfm has succeeded.

Move the setting into crypto_clone_ahash and crypto_clone_shash
instead.

Also clone the fb if necessary.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/ahash.c

@@ -877,6 +877,7 @@ struct crypto_ahash *crypto_clone_ahash(struct crypto_ahash *hash)
 {
 	struct hash_alg_common *halg = crypto_hash_alg_common(hash);
 	struct crypto_tfm *tfm = crypto_ahash_tfm(hash);
+	struct crypto_ahash *fb = NULL;
 	struct crypto_ahash *nhash;
 	struct ahash_alg *alg;
 	int err;
@@ -906,22 +907,36 @@ struct crypto_ahash *crypto_clone_ahash(struct crypto_ahash *hash)
 			err = PTR_ERR(shash);
 			goto out_free_nhash;
 		}
+		crypto_ahash_tfm(nhash)->exit = crypto_exit_ahash_using_shash;
 		nhash->using_shash = true;
 		*nctx = shash;
 		return nhash;
 	}
 
+	if (ahash_is_async(hash)) {
+		fb = crypto_clone_ahash(crypto_ahash_fb(hash));
+		err = PTR_ERR(fb);
+		if (IS_ERR(fb))
+			goto out_free_nhash;
+
+		crypto_ahash_tfm(nhash)->fb = crypto_ahash_tfm(fb);
+	}
+
 	err = -ENOSYS;
 	alg = crypto_ahash_alg(hash);
 	if (!alg->clone_tfm)
-		goto out_free_nhash;
+		goto out_free_fb;
 
 	err = alg->clone_tfm(nhash, hash);
 	if (err)
-		goto out_free_nhash;
+		goto out_free_fb;
+
+	crypto_ahash_tfm(nhash)->exit = crypto_ahash_exit_tfm;
 
 	return nhash;
 
+out_free_fb:
+	crypto_free_ahash(fb);
 out_free_nhash:
 	crypto_free_ahash(nhash);
 	return ERR_PTR(err);

crypto/api.c

@@ -570,7 +570,7 @@ void *crypto_clone_tfm(const struct crypto_type *frontend,
 
 	tfm = (struct crypto_tfm *)(mem + frontend->tfmsize);
 	tfm->crt_flags = otfm->crt_flags;
-	tfm->exit = otfm->exit;
+	tfm->fb = tfm;
 
 out:
 	return mem;

crypto/shash.c

@@ -413,6 +413,9 @@ struct crypto_shash *crypto_clone_shash(struct crypto_shash *hash)
 		}
 	}
 
+	if (alg->exit_tfm)
+		crypto_shash_tfm(nhash)->exit = crypto_shash_exit_tfm;
+
 	return nhash;
 }
 EXPORT_SYMBOL_GPL(crypto_clone_shash);