On Thu, May 27, 2010 at 01:02:09PM +0800, Ang Way Chuang wrote:
> ULE (Unidirectional Lightweight Encapsulation RFC 4326)
> decapsulation code has a bug that incorrectly treats ULE SNDU packed
> into the remaining 2 or 3 bytes of a MPEG2-TS frame as having
> invalid pointer field on the subsequent MPEG2-TS frame.
> 
> This patch was generated and tested against the latest Linus's pre
> 2.6.35-rc1 tree.
> 
> Signed-off-by: Ang Way Chuang <wc...@nav6.org>

Looks good to me, thanks for the updated version. Good catch noting that
error needed to be reset to false after it was handled, I'd missed that.

Acked-by: Jarod Wilson <ja...@redhat.com>

> ---
> diff --git a/drivers/media/dvb/dvb-core/dvb_net.c 
> b/drivers/media/dvb/dvb-core/dvb_net.c
> index f6dac2b..6c3a8a0 100644
> --- a/drivers/media/dvb/dvb-core/dvb_net.c
> +++ b/drivers/media/dvb/dvb-core/dvb_net.c
> @@ -351,6 +351,7 @@ static void dvb_net_ule( struct net_device *dev, const u8 
> *buf, size_t buf_len )
>       const u8 *ts, *ts_end, *from_where = NULL;
>       u8 ts_remain = 0, how_much = 0, new_ts = 1;
>       struct ethhdr *ethh = NULL;
> +     bool error = false;
> 
> #ifdef ULE_DEBUG
>       /* The code inside ULE_DEBUG keeps a history of the last 100 TS cells 
> processed. */
> @@ -460,10 +461,16 @@ static void dvb_net_ule( struct net_device *dev, const 
> u8 *buf, size_t buf_len )
> 
>                                               /* Drop partly decoded SNDU, 
> reset state, resync on PUSI. */
>                                               if (priv->ule_skb) {
> -                                                     dev_kfree_skb( 
> priv->ule_skb );
> +                                                     error = true;
> +                                                     
> dev_kfree_skb(priv->ule_skb);
> +                                             }
> +
> +                                             if (error || 
> priv->ule_sndu_remain) {
>                                                       dev->stats.rx_errors++;
>                                                       
> dev->stats.rx_frame_errors++;
> +                                                     error = false;
>                                               }
> +
>                                               reset_ule(priv);
>                                               priv->need_pusi = 1;
>                                               continue;
> @@ -535,6 +542,7 @@ static void dvb_net_ule( struct net_device *dev, const u8 
> *buf, size_t buf_len )
>                               from_where += 2;
>                       }
> 
> +                     priv->ule_sndu_remain = priv->ule_sndu_len + 2;
>                       /*
>                        * State of current TS:
>                        *   ts_remain (remaining bytes in the current TS cell)
> @@ -544,6 +552,7 @@ static void dvb_net_ule( struct net_device *dev, const u8 
> *buf, size_t buf_len )
>                        */
>                       switch (ts_remain) {
>                               case 1:
> +                                     priv->ule_sndu_remain--;
>                                       priv->ule_sndu_type = from_where[0] << 
> 8;
>                                       priv->ule_sndu_type_1 = 1; /* first 
> byte of ule_type is set. */
>                                       ts_remain -= 1; from_where += 1;
> @@ -557,6 +566,7 @@ static void dvb_net_ule( struct net_device *dev, const u8 
> *buf, size_t buf_len )
>                               default: /* complete ULE header is present in 
> current TS. */
>                                       /* Extract ULE type field. */
>                                       if (priv->ule_sndu_type_1) {
> +                                             priv->ule_sndu_type_1 = 0;
>                                               priv->ule_sndu_type |= 
> from_where[0];
>                                               from_where += 1; /* points to 
> payload start. */
>                                               ts_remain -= 1;

-- 
Jarod Wilson
ja...@redhat.com

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