[CRYPTO] geode: Add fallback for unsupported modes

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.

Signed-off-by: Sebastian Siewior <sebastian@breakpoint.cc>
Acked-by: Jordan Crouse <jordan.crouse@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/geode-aes.c

@@ -113,18 +113,103 @@ 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
@@ -132,8 +217,10 @@ 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;
@@ -151,8 +238,10 @@ 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;
@@ -164,24 +253,50 @@ 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
 		}
 	}
 };
@@ -195,6 +310,9 @@ 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);
@@ -225,6 +343,9 @@ 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);
@@ -245,22 +366,49 @@ 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,
@@ -277,6 +425,9 @@ 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);
 
@@ -304,6 +455,9 @@ 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);
 
@@ -323,21 +477,24 @@ 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,
 		}
@@ -367,7 +524,7 @@ 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);

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