[PATCH] crypto: geode-aes - switch to skcipher for cbc(aes) fallback

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

Commit 79c65d179a40e145 ("crypto: cbc - Convert to skcipher") updated
the generic CBC template wrapper from a blkcipher to a skcipher algo,
to get away from the deprecated blkcipher interface. However, as a side
effect, drivers that instantiate CBC transforms using the blkcipher as
a fallback no longer work, since skciphers can wrap blkciphers but not
the other way around. This broke the geode-aes driver.

So let's fix it by moving to the sync skcipher interface when allocating
the fallback.

Cc: Gert Robben <t2@gert.gr>
Cc: Jelle de Jong <jelledejong@powercraft.nl>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
Gert, Jelle,

If you can, please try this patch and report back to the list if it solves
the Geode issue for you.

-- 
Ard.

 drivers/crypto/geode-aes.c | 45 +++++++++-----------
 drivers/crypto/geode-aes.h |  2 +-
 2 files changed, 22 insertions(+), 25 deletions(-)

diff --git a/drivers/crypto/geode-aes.c b/drivers/crypto/geode-aes.c
index d81a1297cb9e..b6c47bbc2c49 100644
--- a/drivers/crypto/geode-aes.c
+++ b/drivers/crypto/geode-aes.c
@@ -10,6 +10,7 @@
 #include <linux/spinlock.h>
 #include <crypto/algapi.h>
 #include <crypto/aes.h>
+#include <crypto/skcipher.h>
 
 #include <linux/io.h>
 #include <linux/delay.h>
@@ -166,13 +167,15 @@ static int geode_setkey_blk(struct crypto_tfm *tfm, const u8 *key,
 	/*
 	 * The requested key size is not supported by HW, do a fallback
 	 */
-	op->fallback.blk->base.crt_flags &= ~CRYPTO_TFM_REQ_MASK;
-	op->fallback.blk->base.crt_flags |= (tfm->crt_flags & CRYPTO_TFM_REQ_MASK);
+	crypto_sync_skcipher_clear_flags(op->fallback.blk, CRYPTO_TFM_REQ_MASK);
+	crypto_sync_skcipher_set_flags(op->fallback.blk,
+				       tfm->crt_flags & CRYPTO_TFM_REQ_MASK);
 
-	ret = crypto_blkcipher_setkey(op->fallback.blk, key, len);
+	ret = crypto_sync_skcipher_setkey(op->fallback.blk, key, len);
 	if (ret) {
 		tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
-		tfm->crt_flags |= (op->fallback.blk->base.crt_flags & CRYPTO_TFM_RES_MASK);
+		tfm->crt_flags |= crypto_sync_skcipher_get_flags(op->fallback.blk) &
+				  CRYPTO_TFM_RES_MASK;
 	}
 	return ret;
 }
@@ -181,33 +184,28 @@ static int fallback_blk_dec(struct blkcipher_desc *desc,
 		struct scatterlist *dst, struct scatterlist *src,
 		unsigned int nbytes)
 {
-	unsigned int ret;
-	struct crypto_blkcipher *tfm;
 	struct geode_aes_op *op = crypto_blkcipher_ctx(desc->tfm);
+	SYNC_SKCIPHER_REQUEST_ON_STACK(req, op->fallback.blk);
 
-	tfm = desc->tfm;
-	desc->tfm = op->fallback.blk;
-
-	ret = crypto_blkcipher_decrypt_iv(desc, dst, src, nbytes);
+	skcipher_request_set_sync_tfm(req, op->fallback.blk);
+	skcipher_request_set_callback(req, 0, NULL, NULL);
+	skcipher_request_set_crypt(req, dst, src, nbytes, desc->info);
 
-	desc->tfm = tfm;
-	return ret;
+	return crypto_skcipher_decrypt(req);
 }
+
 static int fallback_blk_enc(struct blkcipher_desc *desc,
 		struct scatterlist *dst, struct scatterlist *src,
 		unsigned int nbytes)
 {
-	unsigned int ret;
-	struct crypto_blkcipher *tfm;
 	struct geode_aes_op *op = crypto_blkcipher_ctx(desc->tfm);
+	SYNC_SKCIPHER_REQUEST_ON_STACK(req, op->fallback.blk);
 
-	tfm = desc->tfm;
-	desc->tfm = op->fallback.blk;
-
-	ret = crypto_blkcipher_encrypt_iv(desc, dst, src, nbytes);
+	skcipher_request_set_sync_tfm(req, op->fallback.blk);
+	skcipher_request_set_callback(req, 0, NULL, NULL);
+	skcipher_request_set_crypt(req, dst, src, nbytes, desc->info);
 
-	desc->tfm = tfm;
-	return ret;
+	return crypto_skcipher_encrypt(req);
 }
 
 static void
@@ -366,9 +364,8 @@ static int fallback_init_blk(struct crypto_tfm *tfm)
 	const char *name = crypto_tfm_alg_name(tfm);
 	struct geode_aes_op *op = crypto_tfm_ctx(tfm);
 
-	op->fallback.blk = crypto_alloc_blkcipher(name, 0,
-			CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK);
-
+	op->fallback.blk = crypto_alloc_sync_skcipher(name, 0,
+						      CRYPTO_ALG_NEED_FALLBACK);
 	if (IS_ERR(op->fallback.blk)) {
 		printk(KERN_ERR "Error allocating fallback algo %s\n", name);
 		return PTR_ERR(op->fallback.blk);
@@ -381,7 +378,7 @@ static void fallback_exit_blk(struct crypto_tfm *tfm)
 {
 	struct geode_aes_op *op = crypto_tfm_ctx(tfm);
 
-	crypto_free_blkcipher(op->fallback.blk);
+	crypto_free_sync_skcipher(op->fallback.blk);
 	op->fallback.blk = NULL;
 }
 
diff --git a/drivers/crypto/geode-aes.h b/drivers/crypto/geode-aes.h
index 5c6e131a8f9d..f8a86898ac22 100644
--- a/drivers/crypto/geode-aes.h
+++ b/drivers/crypto/geode-aes.h
@@ -60,7 +60,7 @@ struct geode_aes_op {
 	u8 *iv;
 
 	union {
-		struct crypto_blkcipher *blk;
+		struct crypto_sync_skcipher *blk;
 		struct crypto_cipher *cip;
 	} fallback;
 	u32 keylen;
-- 
2.20.1