crypto: inside-secure - Add support for the AES-XTS algorithm

This patch adds support for the AES-XTS skcipher algorithm.
Signed-off-by: Pascal van Leeuwen <pvanleeuwen@verimatrix.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/inside-secure/safexcel.c

@@ -1004,6 +1004,7 @@ static struct safexcel_alg_template *safexcel_algs[] = {
 	&safexcel_alg_authenc_hmac_sha256_ctr_aes,
 	&safexcel_alg_authenc_hmac_sha384_ctr_aes,
 	&safexcel_alg_authenc_hmac_sha512_ctr_aes,
+	&safexcel_alg_xts_aes,
 };
 
 static int safexcel_register_algorithms(struct safexcel_crypto_priv *priv)

drivers/crypto/inside-secure/safexcel.h

@@ -334,6 +334,7 @@ struct safexcel_context_record {
 #define CONTEXT_CONTROL_CRYPTO_MODE_ECB		(0 << 0)
 #define CONTEXT_CONTROL_CRYPTO_MODE_CBC		(1 << 0)
 #define CONTEXT_CONTROL_CRYPTO_MODE_CTR_LOAD	(6 << 0)
+#define CONTEXT_CONTROL_CRYPTO_MODE_XTS		(7 << 0)
 #define CONTEXT_CONTROL_IV0			BIT(5)
 #define CONTEXT_CONTROL_IV1			BIT(6)
 #define CONTEXT_CONTROL_IV2			BIT(7)
@@ -750,5 +751,6 @@ extern struct safexcel_alg_template safexcel_alg_authenc_hmac_sha224_ctr_aes;
 extern struct safexcel_alg_template safexcel_alg_authenc_hmac_sha256_ctr_aes;
 extern struct safexcel_alg_template safexcel_alg_authenc_hmac_sha384_ctr_aes;
 extern struct safexcel_alg_template safexcel_alg_authenc_hmac_sha512_ctr_aes;
+extern struct safexcel_alg_template safexcel_alg_xts_aes;
 
 #endif

drivers/crypto/inside-secure/safexcel_cipher.c

@@ -15,6 +15,7 @@
 #include <crypto/ctr.h>
 #include <crypto/internal/des.h>
 #include <crypto/sha.h>
+#include <crypto/xts.h>
 #include <crypto/skcipher.h>
 #include <crypto/internal/aead.h>
 #include <crypto/internal/skcipher.h>
@@ -40,9 +41,9 @@ struct safexcel_cipher_ctx {
 	enum safexcel_cipher_alg alg;
 	bool aead;
 
-	__le32 key[8];
+	__le32 key[16];
 	u32 nonce;
-	unsigned int key_len;
+	unsigned int key_len, xts;
 
 	/* All the below is AEAD specific */
 	u32 hash_alg;
@@ -351,7 +352,7 @@ static int safexcel_context_control(struct safexcel_cipher_ctx *ctx,
 	} else if (ctx->alg == SAFEXCEL_3DES) {
 		cdesc->control_data.control0 |= CONTEXT_CONTROL_CRYPTO_ALG_3DES;
 	} else if (ctx->alg == SAFEXCEL_AES) {
-		switch (ctx->key_len) {
+		switch (ctx->key_len >> ctx->xts) {
 		case AES_KEYSIZE_128:
 			cdesc->control_data.control0 |= CONTEXT_CONTROL_CRYPTO_ALG_AES128;
 			break;
@@ -363,7 +364,7 @@ static int safexcel_context_control(struct safexcel_cipher_ctx *ctx,
 			break;
 		default:
 			dev_err(priv->dev, "aes keysize not supported: %u\n",
-				ctx->key_len);
+				ctx->key_len >> ctx->xts);
 			return -EINVAL;
 		}
 	}
@@ -1747,3 +1748,118 @@ struct safexcel_alg_template safexcel_alg_authenc_hmac_sha384_ctr_aes = {
 		},
 	},
 };
+
+static int safexcel_skcipher_aesxts_setkey(struct crypto_skcipher *ctfm,
+					   const u8 *key, unsigned int len)
+{
+	struct crypto_tfm *tfm = crypto_skcipher_tfm(ctfm);
+	struct safexcel_cipher_ctx *ctx = crypto_tfm_ctx(tfm);
+	struct safexcel_crypto_priv *priv = ctx->priv;
+	struct crypto_aes_ctx aes;
+	int ret, i;
+	unsigned int keylen;
+
+	/* Check for illegal XTS keys */
+	ret = xts_verify_key(ctfm, key, len);
+	if (ret)
+		return ret;
+
+	/* Only half of the key data is cipher key */
+	keylen = (len >> 1);
+	ret = aes_expandkey(&aes, key, keylen);
+	if (ret) {
+		crypto_skcipher_set_flags(ctfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
+		return ret;
+	}
+
+	if (priv->flags & EIP197_TRC_CACHE && ctx->base.ctxr_dma) {
+		for (i = 0; i < keylen / sizeof(u32); i++) {
+			if (ctx->key[i] != cpu_to_le32(aes.key_enc[i])) {
+				ctx->base.needs_inv = true;
+				break;
+			}
+		}
+	}
+
+	for (i = 0; i < keylen / sizeof(u32); i++)
+		ctx->key[i] = cpu_to_le32(aes.key_enc[i]);
+
+	/* The other half is the tweak key */
+	ret = aes_expandkey(&aes, (u8 *)(key + keylen), keylen);
+	if (ret) {
+		crypto_skcipher_set_flags(ctfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
+		return ret;
+	}
+
+	if (priv->flags & EIP197_TRC_CACHE && ctx->base.ctxr_dma) {
+		for (i = 0; i < keylen / sizeof(u32); i++) {
+			if (ctx->key[i + keylen / sizeof(u32)] !=
+			    cpu_to_le32(aes.key_enc[i])) {
+				ctx->base.needs_inv = true;
+				break;
+			}
+		}
+	}
+
+	for (i = 0; i < keylen / sizeof(u32); i++)
+		ctx->key[i + keylen / sizeof(u32)] =
+			cpu_to_le32(aes.key_enc[i]);
+
+	ctx->key_len = keylen << 1;
+
+	memzero_explicit(&aes, sizeof(aes));
+	return 0;
+}
+
+static int safexcel_skcipher_aes_xts_cra_init(struct crypto_tfm *tfm)
+{
+	struct safexcel_cipher_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	safexcel_skcipher_cra_init(tfm);
+	ctx->alg  = SAFEXCEL_AES;
+	ctx->xts  = 1;
+	ctx->mode = CONTEXT_CONTROL_CRYPTO_MODE_XTS;
+	return 0;
+}
+
+static int safexcel_encrypt_xts(struct skcipher_request *req)
+{
+	if (req->cryptlen < XTS_BLOCK_SIZE)
+		return -EINVAL;
+	return safexcel_queue_req(&req->base, skcipher_request_ctx(req),
+				  SAFEXCEL_ENCRYPT);
+}
+
+static int safexcel_decrypt_xts(struct skcipher_request *req)
+{
+	if (req->cryptlen < XTS_BLOCK_SIZE)
+		return -EINVAL;
+	return safexcel_queue_req(&req->base, skcipher_request_ctx(req),
+				  SAFEXCEL_DECRYPT);
+}
+
+struct safexcel_alg_template safexcel_alg_xts_aes = {
+	.type = SAFEXCEL_ALG_TYPE_SKCIPHER,
+	.alg.skcipher = {
+		.setkey = safexcel_skcipher_aesxts_setkey,
+		.encrypt = safexcel_encrypt_xts,
+		.decrypt = safexcel_decrypt_xts,
+		/* XTS actually uses 2 AES keys glued together */
+		.min_keysize = AES_MIN_KEY_SIZE * 2,
+		.max_keysize = AES_MAX_KEY_SIZE * 2,
+		.ivsize = XTS_BLOCK_SIZE,
+		.base = {
+			.cra_name = "xts(aes)",
+			.cra_driver_name = "safexcel-xts-aes",
+			.cra_priority = 300,
+			.cra_flags = CRYPTO_ALG_ASYNC |
+				     CRYPTO_ALG_KERN_DRIVER_ONLY,
+			.cra_blocksize = XTS_BLOCK_SIZE,
+			.cra_ctxsize = sizeof(struct safexcel_cipher_ctx),
+			.cra_alignmask = 0,
+			.cra_init = safexcel_skcipher_aes_xts_cra_init,
+			.cra_exit = safexcel_skcipher_cra_exit,
+			.cra_module = THIS_MODULE,
+		},
+	},
+};