[PATCH] [crypto] geode: add fallback for unsupported modes, take 2

[Sebastian Siewior <linux-crypto@ml.breakpoint.cc>]

The Geode AES crypto engine supports only 128 bit long key. This
patch adds fallback for other key sizes which are required by the
AES standard.

Cc: Jordan Crouse <jordan.crouse@amd.com>
Signed-off-by: Sebastian Siewior <sebastian@breakpoint.cc>
---

Herbert, as you suggested I splitted cipher & blk code.

diff --git a/drivers/crypto/geode-aes.c b/drivers/crypto/geode-aes.c
index da6164a..f2d4fba 100644
--- a/drivers/crypto/geode-aes.c
+++ b/drivers/crypto/geode-aes.c
@@ -114,18 +114,103 @@ geode_aes_crypt(struct geode_aes_op *op)
 
 /* CRYPTO-API Functions */
 
-static int
-geode_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int len)
+static int geode_setkey_cip(struct crypto_tfm *tfm, const u8 *key,
+		unsigned int len)
 {
 	struct geode_aes_op *op = crypto_tfm_ctx(tfm);
+	unsigned int ret;
+
+	op->keylen = len;
+
+	if (len == AES_KEYSIZE_128) {
+		memcpy(op->key, key, len);
+		return 0;
+	}
 
-	if (len != AES_KEY_LENGTH) {
+	if (len != AES_KEYSIZE_192 && len != AES_KEYSIZE_256) {
+		/* not supported at all */
 		tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 		return -EINVAL;
 	}
 
-	memcpy(op->key, key, len);
-	return 0;
+	/*
+	 * 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);
+
+	ret = crypto_cipher_setkey(op->fallback.cip, key, len);
+	if (ret) {
+		tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
+		tfm->crt_flags |= (op->fallback.blk->base.crt_flags & CRYPTO_TFM_RES_MASK);
+	}
+	return ret;
+}
+
+static int geode_setkey_blk(struct crypto_tfm *tfm, const u8 *key,
+		unsigned int len)
+{
+	struct geode_aes_op *op = crypto_tfm_ctx(tfm);
+	unsigned int ret;
+
+	op->keylen = len;
+
+	if (len == AES_KEYSIZE_128) {
+		memcpy(op->key, key, len);
+		return 0;
+	}
+
+	if (len != AES_KEYSIZE_192 && len != AES_KEYSIZE_256) {
+		/* not supported at all */
+		tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+		return -EINVAL;
+	}
+
+	/*
+	 * 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);
+
+	ret = crypto_blkcipher_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);
+	}
+	return ret;
+}
+
+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);
+
+	tfm = desc->tfm;
+	desc->tfm = op->fallback.blk;
+
+	ret = crypto_blkcipher_decrypt(desc, dst, src, nbytes);
+
+	desc->tfm = tfm;
+	return ret;
+}
+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);
+
+	tfm = desc->tfm;
+	desc->tfm = op->fallback.blk;
+
+	ret = crypto_blkcipher_encrypt(desc, dst, src, nbytes);
+
+	desc->tfm = tfm;
+	return ret;
 }
 
 static void
@@ -133,8 +218,10 @@ geode_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
 {
 	struct geode_aes_op *op = crypto_tfm_ctx(tfm);
 
-	if ((out == NULL) || (in == NULL))
+	if (unlikely(op->keylen != AES_KEYSIZE_128)) {
+		crypto_cipher_encrypt_one(op->fallback.cip, out, in);
 		return;
+	}
 
 	op->src = (void *) in;
 	op->dst = (void *) out;
@@ -152,8 +239,10 @@ geode_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
 {
 	struct geode_aes_op *op = crypto_tfm_ctx(tfm);
 
-	if ((out == NULL) || (in == NULL))
+	if (unlikely(op->keylen != AES_KEYSIZE_128)) {
+		crypto_cipher_decrypt_one(op->fallback.cip, out, in);
 		return;
+	}
 
 	op->src = (void *) in;
 	op->dst = (void *) out;
@@ -165,24 +254,50 @@ geode_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
 	geode_aes_crypt(op);
 }
 
+static int fallback_init_cip(struct crypto_tfm *tfm)
+{
+	const char *name = tfm->__crt_alg->cra_name;
+	struct geode_aes_op *op = crypto_tfm_ctx(tfm);
+
+	op->fallback.cip = crypto_alloc_cipher(name, 0,
+				CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK);
+
+	if (IS_ERR(op->fallback.cip)) {
+		printk(KERN_ERR "Error allocating fallback algo %s\n", name);
+		return PTR_ERR(op->fallback.blk);
+	}
+
+	return 0;
+}
+
+static void fallback_exit_cip(struct crypto_tfm *tfm)
+{
+	struct geode_aes_op *op = crypto_tfm_ctx(tfm);
+
+	crypto_free_cipher(op->fallback.cip);
+	op->fallback.cip = NULL;
+}
 
 static struct crypto_alg geode_alg = {
-	.cra_name               =       "aes",
-	.cra_driver_name	=       "geode-aes-128",
-	.cra_priority           =       300,
-	.cra_alignmask          =       15,
-	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
+	.cra_name			=	"aes",
+	.cra_driver_name	=	"geode-aes",
+	.cra_priority		=	300,
+	.cra_alignmask		=	15,
+	.cra_flags			=	CRYPTO_ALG_TYPE_CIPHER |
+							CRYPTO_ALG_NEED_FALLBACK,
+	.cra_init			=	fallback_init_cip,
+	.cra_exit			=	fallback_exit_cip,
 	.cra_blocksize		=	AES_MIN_BLOCK_SIZE,
 	.cra_ctxsize		=	sizeof(struct geode_aes_op),
-	.cra_module		=	THIS_MODULE,
-	.cra_list		=	LIST_HEAD_INIT(geode_alg.cra_list),
-	.cra_u			=	{
-		.cipher = {
-			.cia_min_keysize	=  AES_KEY_LENGTH,
-			.cia_max_keysize	=  AES_KEY_LENGTH,
-			.cia_setkey		=  geode_setkey,
-			.cia_encrypt		=  geode_encrypt,
-			.cia_decrypt		=  geode_decrypt
+	.cra_module			=	THIS_MODULE,
+	.cra_list			=	LIST_HEAD_INIT(geode_alg.cra_list),
+	.cra_u				=	{
+		.cipher	=	{
+			.cia_min_keysize	=	AES_MIN_KEY_SIZE,
+			.cia_max_keysize	=	AES_MAX_KEY_SIZE,
+			.cia_setkey			=	geode_setkey_cip,
+			.cia_encrypt		=	geode_encrypt,
+			.cia_decrypt		=	geode_decrypt
 		}
 	}
 };
@@ -196,6 +311,9 @@ geode_cbc_decrypt(struct blkcipher_desc *desc,
 	struct blkcipher_walk walk;
 	int err, ret;
 
+	if (unlikely(op->keylen != AES_KEYSIZE_128))
+		return fallback_blk_dec(desc, dst, src, nbytes);
+
 	blkcipher_walk_init(&walk, dst, src, nbytes);
 	err = blkcipher_walk_virt(desc, &walk);
 	memcpy(op->iv, walk.iv, AES_IV_LENGTH);
@@ -226,6 +344,9 @@ geode_cbc_encrypt(struct blkcipher_desc *desc,
 	struct blkcipher_walk walk;
 	int err, ret;
 
+	if (unlikely(op->keylen != AES_KEYSIZE_128))
+		return fallback_blk_enc(desc, dst, src, nbytes);
+
 	blkcipher_walk_init(&walk, dst, src, nbytes);
 	err = blkcipher_walk_virt(desc, &walk);
 	memcpy(op->iv, walk.iv, AES_IV_LENGTH);
@@ -246,22 +367,49 @@ geode_cbc_encrypt(struct blkcipher_desc *desc,
 	return err;
 }
 
+static int fallback_init_blk(struct crypto_tfm *tfm)
+{
+	const char *name = tfm->__crt_alg->cra_name;
+	struct geode_aes_op *op = crypto_tfm_ctx(tfm);
+
+	op->fallback.blk = crypto_alloc_blkcipher(name, 0,
+			CRYPTO_ALG_ASYNC | 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);
+	}
+
+	return 0;
+}
+
+static void fallback_exit_blk(struct crypto_tfm *tfm)
+{
+	struct geode_aes_op *op = crypto_tfm_ctx(tfm);
+
+	crypto_free_blkcipher(op->fallback.blk);
+	op->fallback.blk = NULL;
+}
+
 static struct crypto_alg geode_cbc_alg = {
 	.cra_name		=	"cbc(aes)",
-	.cra_driver_name	=	"cbc-aes-geode-128",
+	.cra_driver_name	=	"cbc-aes-geode",
 	.cra_priority		=	400,
-	.cra_flags		=	CRYPTO_ALG_TYPE_BLKCIPHER,
+	.cra_flags			=	CRYPTO_ALG_TYPE_BLKCIPHER |
+							CRYPTO_ALG_NEED_FALLBACK,
+	.cra_init			=	fallback_init_blk,
+	.cra_exit			=	fallback_exit_blk,
 	.cra_blocksize		=	AES_MIN_BLOCK_SIZE,
 	.cra_ctxsize		=	sizeof(struct geode_aes_op),
 	.cra_alignmask		=	15,
-	.cra_type		=	&crypto_blkcipher_type,
-	.cra_module		=	THIS_MODULE,
-	.cra_list		=	LIST_HEAD_INIT(geode_cbc_alg.cra_list),
-	.cra_u			=	{
-		.blkcipher = {
-			.min_keysize		=	AES_KEY_LENGTH,
-			.max_keysize		=	AES_KEY_LENGTH,
-			.setkey			=	geode_setkey,
+	.cra_type			=	&crypto_blkcipher_type,
+	.cra_module			=	THIS_MODULE,
+	.cra_list			=	LIST_HEAD_INIT(geode_cbc_alg.cra_list),
+	.cra_u				=	{
+		.blkcipher	=	{
+			.min_keysize	=	AES_MIN_KEY_SIZE,
+			.max_keysize	=	AES_MAX_KEY_SIZE,
+			.setkey			=	geode_setkey_blk,
 			.encrypt		=	geode_cbc_encrypt,
 			.decrypt		=	geode_cbc_decrypt,
 			.ivsize			=	AES_IV_LENGTH,
@@ -278,6 +426,9 @@ geode_ecb_decrypt(struct blkcipher_desc *desc,
 	struct blkcipher_walk walk;
 	int err, ret;
 
+	if (unlikely(op->keylen != AES_KEYSIZE_128))
+		return fallback_blk_dec(desc, dst, src, nbytes);
+
 	blkcipher_walk_init(&walk, dst, src, nbytes);
 	err = blkcipher_walk_virt(desc, &walk);
 
@@ -305,6 +456,9 @@ geode_ecb_encrypt(struct blkcipher_desc *desc,
 	struct blkcipher_walk walk;
 	int err, ret;
 
+	if (unlikely(op->keylen != AES_KEYSIZE_128))
+		return fallback_blk_enc(desc, dst, src, nbytes);
+
 	blkcipher_walk_init(&walk, dst, src, nbytes);
 	err = blkcipher_walk_virt(desc, &walk);
 
@@ -324,21 +478,24 @@ geode_ecb_encrypt(struct blkcipher_desc *desc,
 }
 
 static struct crypto_alg geode_ecb_alg = {
-	.cra_name		=	"ecb(aes)",
-	.cra_driver_name	=	"ecb-aes-geode-128",
+	.cra_name			=	"ecb(aes)",
+	.cra_driver_name	=	"ecb-aes-geode",
 	.cra_priority		=	400,
-	.cra_flags		=	CRYPTO_ALG_TYPE_BLKCIPHER,
+	.cra_flags			=	CRYPTO_ALG_TYPE_BLKCIPHER |
+							CRYPTO_ALG_NEED_FALLBACK,
+	.cra_init			=	fallback_init_blk,
+	.cra_exit			=	fallback_exit_blk,
 	.cra_blocksize		=	AES_MIN_BLOCK_SIZE,
 	.cra_ctxsize		=	sizeof(struct geode_aes_op),
 	.cra_alignmask		=	15,
-	.cra_type		=	&crypto_blkcipher_type,
-	.cra_module		=	THIS_MODULE,
-	.cra_list		=	LIST_HEAD_INIT(geode_ecb_alg.cra_list),
-	.cra_u			=	{
-		.blkcipher = {
-			.min_keysize		=	AES_KEY_LENGTH,
-			.max_keysize		=	AES_KEY_LENGTH,
-			.setkey			=	geode_setkey,
+	.cra_type			=	&crypto_blkcipher_type,
+	.cra_module			=	THIS_MODULE,
+	.cra_list			=	LIST_HEAD_INIT(geode_ecb_alg.cra_list),
+	.cra_u				=	{
+		.blkcipher	=	{
+			.min_keysize	=	AES_MIN_KEY_SIZE,
+			.max_keysize	=	AES_MAX_KEY_SIZE,
+			.setkey			=	geode_setkey_blk,
 			.encrypt		=	geode_ecb_encrypt,
 			.decrypt		=	geode_ecb_decrypt,
 		}
@@ -368,7 +525,7 @@ geode_aes_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	if ((ret = pci_enable_device(dev)))
 		return ret;
 
-	if ((ret = pci_request_regions(dev, "geode-aes-128")))
+	if ((ret = pci_request_regions(dev, "geode-aes")))
 		goto eenable;
 
 	_iobase = pci_iomap(dev, 0, 0);
diff --git a/drivers/crypto/geode-aes.h b/drivers/crypto/geode-aes.h
index 2f1d559..14cc763 100644
--- a/drivers/crypto/geode-aes.h
+++ b/drivers/crypto/geode-aes.h
@@ -66,6 +66,12 @@ struct geode_aes_op {
 
 	u8 key[AES_KEY_LENGTH];
 	u8 iv[AES_IV_LENGTH];
+
+	union {
+		struct crypto_blkcipher *blk;
+		struct crypto_cipher *cip;
+	} fallback;
+	u32 keylen;
 };
 
 #endif
-- 
1.5.3.4