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V4L/DVB: dvb-core: Fix ULE decapsulation bug

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Fix ULE decapsulation bug when less than 4 bytes of ULE SNDU is packed
into the remaining bytes of a MPEG2-TS frame

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.

Signed-off-by: Ang Way Chuang <wcang@nav6.org>
Acked-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Ang Way Chuang 2010-05-27 02:02:09 -03:00 committed by Mauro Carvalho Chehab
parent 84b14f181a
commit 5c331fc8c1
1 changed files with 11 additions and 1 deletions
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12
drivers/media/dvb/dvb-core/dvb_net.c
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@ -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;