Re: [Qemu-devel] [PATCH v3] virtio-crypto: zeroize the key material before free

[Gonglei (Arei)]

Hi Michael,

Ping...


Regards,
-Gonglei


> -----Original Message-----
> From: Gonglei (Arei)
> Sent: Thursday, December 22, 2016 11:01 AM
> To: address@hidden
> Cc: address@hidden; Gonglei (Arei)
> Subject: [PATCH v3] virtio-crypto: zeroize the key material before free
> 
> Common practice with sensitive information (key material, passwords,
> etc). Prevents sensitive information from being exposed by accident later in
> coredumps, memory disclosure bugs when heap memory is reused, etc.
> 
> Sensitive information is sometimes also held in mlocked pages to prevent
> it being swapped to disk but that's not being done here.
> 
> Let's zeroize the memory of CryptoDevBackendSymOpInfo structure pointed
> for key material security.
> 
> [Thanks to Stefan for help with crafting the commit message]
> 
> Signed-off-by: Gonglei <address@hidden>
> Reviewed-by: Stefan Hajnoczi <address@hidden>
> Reviewed-by: Eric Blake <address@hidden>
> ---
>  v3:
>  - rework the commit message [Eric]
>  - add Eric's R-by tag.
> 
>  hw/virtio/virtio-crypto.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/virtio/virtio-crypto.c b/hw/virtio/virtio-crypto.c
> index 4f11fee..48288e8 100644
> --- a/hw/virtio/virtio-crypto.c
> +++ b/hw/virtio/virtio-crypto.c
> @@ -337,7 +337,18 @@ static void
> virtio_crypto_free_request(VirtIOCryptoReq *req)
>  {
>      if (req) {
>          if (req->flags == CRYPTODEV_BACKEND_ALG_SYM) {
> -            g_free(req->u.sym_op_info);
> +            size_t max_len;
> +            CryptoDevBackendSymOpInfo *op_info = req->u.sym_op_info;
> +
> +            max_len = op_info->iv_len +
> +                      op_info->aad_len +
> +                      op_info->src_len +
> +                      op_info->dst_len +
> +                      op_info->digest_result_len;
> +
> +            /* Zeroize and free request data structure */
> +            memset(op_info, 0, sizeof(*op_info) + max_len);
> +            g_free(op_info);
>          }
>          g_free(req);
>      }
> --
> 1.8.3.1
>