[PATCH 1/1] crypto: atmel-aes: add support to the XTS mode
Stephan Mueller
smueller at chronox.de
Thu Sep 29 10:44:52 PDT 2016
Am Donnerstag, 29. September 2016, 18:49:07 CEST schrieb Cyrille Pitchen:
Hi Cyrille,
> This patch adds the xts(aes) algorithm, which is supported from
> hardware version 0x500 and above (sama5d2x).
>
> Signed-off-by: Cyrille Pitchen <cyrille.pitchen at atmel.com>
> ---
> drivers/crypto/atmel-aes-regs.h | 4 +
> drivers/crypto/atmel-aes.c | 186
> ++++++++++++++++++++++++++++++++++++++-- 2 files changed, 184
> insertions(+), 6 deletions(-)
>
> diff --git a/drivers/crypto/atmel-aes-regs.h
> b/drivers/crypto/atmel-aes-regs.h index 6c2951bb70b1..0ec04407b533 100644
> --- a/drivers/crypto/atmel-aes-regs.h
> +++ b/drivers/crypto/atmel-aes-regs.h
> @@ -28,6 +28,7 @@
> #define AES_MR_OPMOD_CFB (0x3 << 12)
> #define AES_MR_OPMOD_CTR (0x4 << 12)
> #define AES_MR_OPMOD_GCM (0x5 << 12)
> +#define AES_MR_OPMOD_XTS (0x6 << 12)
> #define AES_MR_LOD (0x1 << 15)
> #define AES_MR_CFBS_MASK (0x7 << 16)
> #define AES_MR_CFBS_128b (0x0 << 16)
> @@ -67,6 +68,9 @@
> #define AES_CTRR 0x98
> #define AES_GCMHR(x) (0x9c + ((x) * 0x04))
>
> +#define AES_TWR(x) (0xc0 + ((x) * 0x04))
> +#define AES_ALPHAR(x) (0xd0 + ((x) * 0x04))
> +
> #define AES_HW_VERSION 0xFC
>
> #endif /* __ATMEL_AES_REGS_H__ */
> diff --git a/drivers/crypto/atmel-aes.c b/drivers/crypto/atmel-aes.c
> index 1d9e7bd3f377..b14c10e98a06 100644
> --- a/drivers/crypto/atmel-aes.c
> +++ b/drivers/crypto/atmel-aes.c
> @@ -68,6 +68,7 @@
> #define AES_FLAGS_CFB8 (AES_MR_OPMOD_CFB | AES_MR_CFBS_8b)
> #define AES_FLAGS_CTR AES_MR_OPMOD_CTR
> #define AES_FLAGS_GCM AES_MR_OPMOD_GCM
> +#define AES_FLAGS_XTS AES_MR_OPMOD_XTS
>
> #define AES_FLAGS_MODE_MASK (AES_FLAGS_OPMODE_MASK | \
> AES_FLAGS_ENCRYPT | \
> @@ -89,6 +90,7 @@ struct atmel_aes_caps {
> bool has_cfb64;
> bool has_ctr32;
> bool has_gcm;
> + bool has_xts;
> u32 max_burst_size;
> };
>
> @@ -135,6 +137,12 @@ struct atmel_aes_gcm_ctx {
> atmel_aes_fn_t ghash_resume;
> };
>
> +struct atmel_aes_xts_ctx {
> + struct atmel_aes_base_ctx base;
> +
> + u32 key2[AES_KEYSIZE_256 / sizeof(u32)];
> +};
> +
> struct atmel_aes_reqctx {
> unsigned long mode;
> };
> @@ -282,6 +290,20 @@ static const char *atmel_aes_reg_name(u32 offset, char
> *tmp, size_t sz) snprintf(tmp, sz, "GCMHR[%u]", (offset - AES_GCMHR(0)) >>
> 2);
> break;
>
> + case AES_TWR(0):
> + case AES_TWR(1):
> + case AES_TWR(2):
> + case AES_TWR(3):
> + snprintf(tmp, sz, "TWR[%u]", (offset - AES_TWR(0)) >> 2);
> + break;
> +
> + case AES_ALPHAR(0):
> + case AES_ALPHAR(1):
> + case AES_ALPHAR(2):
> + case AES_ALPHAR(3):
> + snprintf(tmp, sz, "ALPHAR[%u]", (offset - AES_ALPHAR(0)) >> 2);
> + break;
> +
> default:
> snprintf(tmp, sz, "0x%02x", offset);
> break;
> @@ -453,15 +475,15 @@ static inline int atmel_aes_complete(struct
> atmel_aes_dev *dd, int err) return err;
> }
>
> -static void atmel_aes_write_ctrl(struct atmel_aes_dev *dd, bool use_dma,
> - const u32 *iv)
> +static void atmel_aes_write_ctrl_key(struct atmel_aes_dev *dd, bool
> use_dma, + const u32 *iv, const u32 *key, int keylen)
> {
> u32 valmr = 0;
>
> /* MR register must be set before IV registers */
> - if (dd->ctx->keylen == AES_KEYSIZE_128)
> + if (keylen == AES_KEYSIZE_128)
> valmr |= AES_MR_KEYSIZE_128;
> - else if (dd->ctx->keylen == AES_KEYSIZE_192)
> + else if (keylen == AES_KEYSIZE_192)
> valmr |= AES_MR_KEYSIZE_192;
> else
> valmr |= AES_MR_KEYSIZE_256;
> @@ -478,13 +500,19 @@ static void atmel_aes_write_ctrl(struct atmel_aes_dev
> *dd, bool use_dma,
>
> atmel_aes_write(dd, AES_MR, valmr);
>
> - atmel_aes_write_n(dd, AES_KEYWR(0), dd->ctx->key,
> - SIZE_IN_WORDS(dd->ctx->keylen));
> + atmel_aes_write_n(dd, AES_KEYWR(0), key, SIZE_IN_WORDS(keylen));
>
> if (iv && (valmr & AES_MR_OPMOD_MASK) != AES_MR_OPMOD_ECB)
> atmel_aes_write_block(dd, AES_IVR(0), iv);
> }
>
> +static inline void atmel_aes_write_ctrl(struct atmel_aes_dev *dd, bool
> use_dma, + const u32 *iv)
> +
> +{
> + atmel_aes_write_ctrl_key(dd, use_dma, iv,
> + dd->ctx->key, dd->ctx->keylen);
> +}
>
> /* CPU transfer */
>
> @@ -1769,6 +1797,139 @@ static struct aead_alg aes_gcm_alg = {
> };
>
>
> +/* xts functions */
> +
> +static inline struct atmel_aes_xts_ctx *
> +atmel_aes_xts_ctx_cast(struct atmel_aes_base_ctx *ctx)
> +{
> + return container_of(ctx, struct atmel_aes_xts_ctx, base);
> +}
> +
> +static int atmel_aes_xts_process_data(struct atmel_aes_dev *dd);
> +
> +static int atmel_aes_xts_start(struct atmel_aes_dev *dd)
> +{
> + struct atmel_aes_xts_ctx *ctx = atmel_aes_xts_ctx_cast(dd->ctx);
> + struct ablkcipher_request *req = ablkcipher_request_cast(dd->areq);
> + struct atmel_aes_reqctx *rctx = ablkcipher_request_ctx(req);
> + unsigned long flags;
> + int err;
> +
> + atmel_aes_set_mode(dd, rctx);
> +
> + err = atmel_aes_hw_init(dd);
> + if (err)
> + return atmel_aes_complete(dd, err);
> +
> + /* Compute the tweak value from req->info with ecb(aes). */
> + flags = dd->flags;
> + dd->flags &= ~AES_FLAGS_MODE_MASK;
> + dd->flags |= (AES_FLAGS_ECB | AES_FLAGS_ENCRYPT);
> + atmel_aes_write_ctrl_key(dd, false, NULL,
> + ctx->key2, ctx->base.keylen);
> + dd->flags = flags;
> +
> + atmel_aes_write_block(dd, AES_IDATAR(0), req->info);
> + return atmel_aes_wait_for_data_ready(dd, atmel_aes_xts_process_data);
> +}
> +
> +static int atmel_aes_xts_process_data(struct atmel_aes_dev *dd)
> +{
> + struct ablkcipher_request *req = ablkcipher_request_cast(dd->areq);
> + bool use_dma = (req->nbytes >= ATMEL_AES_DMA_THRESHOLD);
> + u32 tweak[AES_BLOCK_SIZE / sizeof(u32)];
> + static const u32 one[AES_BLOCK_SIZE / sizeof(u32)] = {cpu_to_le32(1), };
> + u8 *tweak_bytes = (u8 *)tweak;
> + int i;
> +
> + /* Read the computed ciphered tweak value. */
> + atmel_aes_read_block(dd, AES_ODATAR(0), tweak);
> + /*
> + * Hardware quirk:
> + * the order of the ciphered tweak bytes need to be reverted before
> + * writing them into the ODATARx registers.
> + */
> + for (i = 0; i < AES_BLOCK_SIZE/2; ++i) {
> + u8 tmp = tweak_bytes[AES_BLOCK_SIZE - 1 - i];
> +
> + tweak_bytes[AES_BLOCK_SIZE - 1 - i] = tweak_bytes[i];
> + tweak_bytes[i] = tmp;
> + }
> +
> + /* Process the data. */
> + atmel_aes_write_ctrl(dd, use_dma, NULL);
> + atmel_aes_write_block(dd, AES_TWR(0), tweak);
> + atmel_aes_write_block(dd, AES_ALPHAR(0), one);
> + if (use_dma)
> + return atmel_aes_dma_start(dd, req->src, req->dst, req->nbytes,
> + atmel_aes_transfer_complete);
> +
> + return atmel_aes_cpu_start(dd, req->src, req->dst, req->nbytes,
> + atmel_aes_transfer_complete);
> +}
> +
> +static int atmel_aes_xts_setkey(struct crypto_ablkcipher *tfm, const u8
> *key, + unsigned int keylen)
> +{
> + struct atmel_aes_xts_ctx *ctx = crypto_ablkcipher_ctx(tfm);
> +
> + if (keylen != AES_KEYSIZE_128 * 2 &&
> + keylen != AES_KEYSIZE_192 * 2 &&
> + keylen != AES_KEYSIZE_256 * 2) {
> + crypto_ablkcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
> + return -EINVAL;
> + }
Please use xts_check_key as a replacement for this code.
> +
> + memcpy(ctx->base.key, key, keylen/2);
> + memcpy(ctx->key2, key + keylen/2, keylen/2);
> + ctx->base.keylen = keylen/2;
> +
> + return 0;
> +}
> +
> +static int atmel_aes_xts_encrypt(struct ablkcipher_request *req)
> +{
> + return atmel_aes_crypt(req, AES_FLAGS_XTS | AES_FLAGS_ENCRYPT);
> +}
> +
> +static int atmel_aes_xts_decrypt(struct ablkcipher_request *req)
> +{
> + return atmel_aes_crypt(req, AES_FLAGS_XTS);
> +}
> +
> +static int atmel_aes_xts_cra_init(struct crypto_tfm *tfm)
> +{
> + struct atmel_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
> +
> + tfm->crt_ablkcipher.reqsize = sizeof(struct atmel_aes_reqctx);
> + ctx->base.start = atmel_aes_xts_start;
> +
> + return 0;
> +}
> +
> +static struct crypto_alg aes_xts_alg = {
> + .cra_name = "xts(aes)",
> + .cra_driver_name = "atmel-xts-aes",
> + .cra_priority = ATMEL_AES_PRIORITY,
> + .cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
> + .cra_blocksize = AES_BLOCK_SIZE,
> + .cra_ctxsize = sizeof(struct atmel_aes_xts_ctx),
> + .cra_alignmask = 0xf,
> + .cra_type = &crypto_ablkcipher_type,
> + .cra_module = THIS_MODULE,
> + .cra_init = atmel_aes_xts_cra_init,
> + .cra_exit = atmel_aes_cra_exit,
> + .cra_u.ablkcipher = {
> + .min_keysize = 2 * AES_MIN_KEY_SIZE,
> + .max_keysize = 2 * AES_MAX_KEY_SIZE,
> + .ivsize = AES_BLOCK_SIZE,
> + .setkey = atmel_aes_xts_setkey,
> + .encrypt = atmel_aes_xts_encrypt,
> + .decrypt = atmel_aes_xts_decrypt,
> + }
> +};
> +
> +
> /* Probe functions */
>
> static int atmel_aes_buff_init(struct atmel_aes_dev *dd)
> @@ -1877,6 +2038,9 @@ static void atmel_aes_unregister_algs(struct
> atmel_aes_dev *dd) {
> int i;
>
> + if (dd->caps.has_xts)
> + crypto_unregister_alg(&aes_xts_alg);
> +
> if (dd->caps.has_gcm)
> crypto_unregister_aead(&aes_gcm_alg);
>
> @@ -1909,8 +2073,16 @@ static int atmel_aes_register_algs(struct
> atmel_aes_dev *dd) goto err_aes_gcm_alg;
> }
>
> + if (dd->caps.has_xts) {
> + err = crypto_register_alg(&aes_xts_alg);
> + if (err)
> + goto err_aes_xts_alg;
> + }
> +
> return 0;
>
> +err_aes_xts_alg:
> + crypto_unregister_aead(&aes_gcm_alg);
> err_aes_gcm_alg:
> crypto_unregister_alg(&aes_cfb64_alg);
> err_aes_cfb64_alg:
> @@ -1928,6 +2100,7 @@ static void atmel_aes_get_cap(struct atmel_aes_dev
> *dd) dd->caps.has_cfb64 = 0;
> dd->caps.has_ctr32 = 0;
> dd->caps.has_gcm = 0;
> + dd->caps.has_xts = 0;
> dd->caps.max_burst_size = 1;
>
> /* keep only major version number */
> @@ -1937,6 +2110,7 @@ static void atmel_aes_get_cap(struct atmel_aes_dev
> *dd) dd->caps.has_cfb64 = 1;
> dd->caps.has_ctr32 = 1;
> dd->caps.has_gcm = 1;
> + dd->caps.has_xts = 1;
> dd->caps.max_burst_size = 4;
> break;
> case 0x200:
Ciao
Stephan
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