Re: [Qemu-devel] [PATCH for-2.9 1/2] cryptodev: fix the check of aes algorithm

[Gonglei (Arei)]

> -----Original Message-----
> From: longpeng
> Sent: Monday, December 05, 2016 3:44 PM
> To: Gonglei (Arei)
> Cc: longpeng; address@hidden; Wubin (H); Zhoujian (jay, Euler)
> Subject: [PATCH for-2.9 1/2] cryptodev: fix the check of aes algorithm
> 
> As the key length of xts(aes) is different with other mode of aes,
> so we should check specially in cryptodev_builtin_get_aes_algo, if
> it is xts mode.
> 
> Signed-off-by: Longpeng(Mike) <address@hidden>
> ---
>  backends/cryptodev-builtin.c | 47
> +++++++++++++++++++++++++++++++-------------
>  1 file changed, 33 insertions(+), 14 deletions(-)
> 
> diff --git a/backends/cryptodev-builtin.c b/backends/cryptodev-builtin.c
> index eda954b..9dec6b8 100644
> --- a/backends/cryptodev-builtin.c
> +++ b/backends/cryptodev-builtin.c
> @@ -111,23 +111,42 @@ cryptodev_builtin_get_unused_session_index(
>      return -1;
>  }
> 
> +#define AES_KEYSIZE_128 16
> +#define AES_KEYSIZE_128_XTS 32
> +#define AES_KEYSIZE_192 24
> +#define AES_KEYSIZE_256 32
> +#define AES_KEYSIZE_256_XTS 64
> +
>  static int
> -cryptodev_builtin_get_aes_algo(uint32_t key_len, Error **errp)
> +cryptodev_builtin_get_aes_algo(uint32_t key_len, int mode, Error **errp)
>  {
>      int algo;
> 
> -    if (key_len == 128 / 8) {
> +    if (key_len == AES_KEYSIZE_128) {
>          algo = QCRYPTO_CIPHER_ALG_AES_128;
> -    } else if (key_len == 192 / 8) {
> +    } else if (key_len == AES_KEYSIZE_192) {
>          algo = QCRYPTO_CIPHER_ALG_AES_192;
> -    } else if (key_len == 256 / 8) {
> -        algo = QCRYPTO_CIPHER_ALG_AES_256;
> +    } else if (key_len == AES_KEYSIZE_256) { /* equals AES_KEYSIZE_128_XTS
> */

So I think you can:
        #define AES_KEYSIZE_128_XTS  AES_KEYSIZE_256


Regards,
-Gonglei

> +        if (mode == QCRYPTO_CIPHER_MODE_XTS) {
> +            algo = QCRYPTO_CIPHER_ALG_AES_128;
> +        } else {
> +            algo = QCRYPTO_CIPHER_ALG_AES_256;
> +        }
> +    } else if (key_len == AES_KEYSIZE_256_XTS) {
> +        if (mode == QCRYPTO_CIPHER_MODE_XTS) {
> +            algo = QCRYPTO_CIPHER_ALG_AES_256;
> +        } else {
> +            goto err;
> +        }
>      } else {
> -        error_setg(errp, "Unsupported key length :%u", key_len);
> -        return -1;
> +        goto err;
>      }
> 
>      return algo;
> +
> +err:
> +   error_setg(errp, "Unsupported key length :%u", key_len);
> +   return -1;
>  }
> 
>  static int cryptodev_builtin_create_cipher_session(
> @@ -155,32 +174,32 @@ static int cryptodev_builtin_create_cipher_session(
> 
>      switch (sess_info->cipher_alg) {
>      case VIRTIO_CRYPTO_CIPHER_AES_ECB:
> +        mode = QCRYPTO_CIPHER_MODE_ECB;
>          algo = cryptodev_builtin_get_aes_algo(sess_info->key_len,
> -                                                          errp);
> +                                                    mode, errp);
>          if (algo < 0)  {
>              return -1;
>          }
> -        mode = QCRYPTO_CIPHER_MODE_ECB;
>          break;
>      case VIRTIO_CRYPTO_CIPHER_AES_CBC:
> +        mode = QCRYPTO_CIPHER_MODE_CBC;
>          algo = cryptodev_builtin_get_aes_algo(sess_info->key_len,
> -                                                          errp);
> +                                                    mode, errp);
>          if (algo < 0)  {
>              return -1;
>          }
> -        mode = QCRYPTO_CIPHER_MODE_CBC;
>          break;
>      case VIRTIO_CRYPTO_CIPHER_AES_CTR:
> +        mode = QCRYPTO_CIPHER_MODE_CTR;
>          algo = cryptodev_builtin_get_aes_algo(sess_info->key_len,
> -                                                          errp);
> +                                                    mode, errp);
>          if (algo < 0)  {
>              return -1;
>          }
> -        mode = QCRYPTO_CIPHER_MODE_CTR;
>          break;
>      case VIRTIO_CRYPTO_CIPHER_DES_ECB:
> -        algo = QCRYPTO_CIPHER_ALG_DES_RFB;
>          mode = QCRYPTO_CIPHER_MODE_ECB;
> +        algo = QCRYPTO_CIPHER_ALG_DES_RFB;
>          break;
>      default:
>          error_setg(errp, "Unsupported cipher alg :%u",
> --
> 1.8.3.1
>