Re: [PATCH net 4/4] tls: Fix tls_device receive

[Dave Watson <davejwatson@fb.com>]

On 02/26/19 02:12 PM, Boris Pismenny wrote:
> Currently, the receive function fails to handle records already
> decrypted by the device due to the commit mentioned below.
> 
> This commit advances the TLS record sequence number and prepares the context
> to handle the next record.
> 
> Fixes: fedf201e1296 ("net: tls: Refactor control message handling on recv")
> Signed-off-by: Boris Pismenny <borisp@mellanox.com>
> Reviewed-by: Eran Ben Elisha <eranbe@mellanox.com>
> ---
>  net/tls/tls_sw.c | 15 +++++++--------
>  1 file changed, 7 insertions(+), 8 deletions(-)
> 
> diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
> index f515cd7e984e..85da10182d8d 100644
> --- a/net/tls/tls_sw.c
> +++ b/net/tls/tls_sw.c
> @@ -1481,18 +1481,17 @@ static int decrypt_skb_update(struct sock *sk, struct sk_buff *skb,
>  
>  			return err;
>  		}
> -
> -		rxm->full_len -= padding_length(ctx, tls_ctx, skb);
> -
> -		rxm->offset += prot->prepend_size;
> -		rxm->full_len -= prot->overhead_size;
> -		tls_advance_record_sn(sk, &tls_ctx->rx, version);
> -		ctx->decrypted = true;
> -		ctx->saved_data_ready(sk);
>  	} else {
>  		*zc = false;
>  	}
>  
> +	rxm->full_len -= padding_length(ctx, tls_ctx, skb);
> +	rxm->offset += prot->prepend_size;
> +	rxm->full_len -= prot->overhead_size;
> +	tls_advance_record_sn(sk, &tls_ctx->rx, version);
> +	ctx->decrypted = true;
> +	ctx->saved_data_ready(sk);
> +
>  	return err;
>  }

This breaks the tls.control_msg test:

  [ RUN      ] tls.control_msg
  tls.c:764:tls.control_msg:Expected memcmp(buf, test_str, send_len) (18446744073709551614) == 0 (0)
  tls.c:777:tls.control_msg:Expected memcmp(buf, test_str, send_len) (18446744073709551614) == 0 (0)
  tls.control_msg: Test failed at step #8

So either control message handling needs to only call
decrypt_skb_update once, or we need a new flag or something to handle
the device case