Sorry, line wrap again. I shall test and fix the problem first before
resending the patch.
On Tue, Nov 24, 2009 at 4:04 PM, Ang Way Chuang <wcang79@xxxxxxxxx> wrote:
> Okay, resending. Hope it won't do line wrapping.
>
> 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 v2.6.32-rc8. Similar patch
> was applied and tested using 2.6.27 which is similar to the latest
> dvb_net.c, except for network device statistical data structure. I
> suspect that this bug was introduced in kernel version 2.6.15, but had
> not verified it.
>
> Care has been taken not to introduce more bug by fixing this bug, but
> please scrutinize the code for I always produces buggy code.
>
> Signed-off-by: Ang Way Chuang <wcang@xxxxxxxx>
> ---
> diff --git a/drivers/media/dvb/dvb-core/dvb_net.c
> b/drivers/media/dvb/dvb-core/dvb_net.c
> index 0241a7c..7e0db86 100644
> --- a/drivers/media/dvb/dvb-core/dvb_net.c
> +++ b/drivers/media/dvb/dvb-core/dvb_net.c
> @@ -458,8 +458,9 @@ static void dvb_net_ule( struct net_device *dev,
> const u8 *buf, size_t buf_len )
> "field: %u.\n", priv->ts_count, *from_where);
>
> /* Drop partly decoded SNDU, reset state, resync on PUSI. */
> - if (priv->ule_skb) {
> - dev_kfree_skb( priv->ule_skb );
> + if (priv->ule_skb || priv->ule_sndu_remain) {
> + if (priv->ule_skb)
> + dev_kfree_skb( priv->ule_skb );
> dev->stats.rx_errors++;
> dev->stats.rx_frame_errors++;
> }
> @@ -533,6 +534,7 @@ 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)
> @@ -542,6 +544,7 @@ 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;
> @@ -555,6 +558,7 @@ 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;
>
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