The fixes provided in this patch assigns a valid net_device structure to
skb before dispatching it for further processing.
Scenario #1:
============
Bluetooth 6lowpan receives an uncompressed IPv6 header, and dispatches it
to netif. The following error occurs:
Null pointer dereference error #1 crash log:
[ 845.854013] BUG: unable to handle kernel NULL pointer dereference at
0000000000000048
[ 845.855785] IP: [<ffffffff816e3d36>] enqueue_to_backlog+0x56/0x240
...
[ 845.909459] Call Trace:
[ 845.911678] [<ffffffff816e3f64>] netif_rx_internal+0x44/0xf0
The first modification fixes the NULL pointer dereference error by
assigning dev to the local_skb in order to set a valid net_device before
processing the skb by netif_rx_ni().
Scenario #2:
============
Bluetooth 6lowpan receives an UDP compressed message which needs further
decompression by nhc_udp. The following error occurs:
Null pointer dereference error #2 crash log:
[ 63.295149] BUG: unable to handle kernel NULL pointer dereference at
0000000000000840
[ 63.295931] IP: [<ffffffffc0559540>] udp_uncompress+0x320/0x626
[nhc_udp]
The second modification fixes the NULL pointer dereference error by
assigning dev to the local_skb in the case of a udp compressed packet.
The 6lowpan udp_uncompress function expects that the net_device is set in
the skb when checking lltype.
Signed-off-by: Glenn Ruben Bakke <[email protected]>
Signed-off-by: Lukasz Duda <[email protected]>
---
net/bluetooth/6lowpan.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index d040365..58e1b3c 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -317,6 +317,7 @@ static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
local_skb->protocol = htons(ETH_P_IPV6);
local_skb->pkt_type = PACKET_HOST;
+ local_skb->dev = dev;
skb_set_transport_header(local_skb, sizeof(struct ipv6hdr));
@@ -335,6 +336,8 @@ static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
if (!local_skb)
goto drop;
+ local_skb->dev = dev;
+
ret = iphc_decompress(local_skb, dev, chan);
if (ret < 0) {
kfree_skb(local_skb);
@@ -343,7 +346,6 @@ static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
local_skb->protocol = htons(ETH_P_IPV6);
local_skb->pkt_type = PACKET_HOST;
- local_skb->dev = dev;
if (give_skb_to_upper(local_skb, dev)
!= NET_RX_SUCCESS) {
--
2.5.0
Hi Glenn,
On Wed, Jan 13, 2016, Glenn Ruben Bakke wrote:
> The fixes provided in this patch assigns a valid net_device structure to
> skb before dispatching it for further processing.
>
> Scenario #1:
> ============
>
> Bluetooth 6lowpan receives an uncompressed IPv6 header, and dispatches it
> to netif. The following error occurs:
>
> Null pointer dereference error #1 crash log:
>
> [ 845.854013] BUG: unable to handle kernel NULL pointer dereference at
> 0000000000000048
> [ 845.855785] IP: [<ffffffff816e3d36>] enqueue_to_backlog+0x56/0x240
> ...
> [ 845.909459] Call Trace:
> [ 845.911678] [<ffffffff816e3f64>] netif_rx_internal+0x44/0xf0
>
> The first modification fixes the NULL pointer dereference error by
> assigning dev to the local_skb in order to set a valid net_device before
> processing the skb by netif_rx_ni().
>
> Scenario #2:
> ============
>
> Bluetooth 6lowpan receives an UDP compressed message which needs further
> decompression by nhc_udp. The following error occurs:
>
> Null pointer dereference error #2 crash log:
>
> [ 63.295149] BUG: unable to handle kernel NULL pointer dereference at
> 0000000000000840
> [ 63.295931] IP: [<ffffffffc0559540>] udp_uncompress+0x320/0x626
> [nhc_udp]
>
> The second modification fixes the NULL pointer dereference error by
> assigning dev to the local_skb in the case of a udp compressed packet.
> The 6lowpan udp_uncompress function expects that the net_device is set in
> the skb when checking lltype.
>
> Signed-off-by: Glenn Ruben Bakke <[email protected]>
> Signed-off-by: Lukasz Duda <[email protected]>
> ---
> net/bluetooth/6lowpan.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
Applied to bluetooth.git. Thanks.
Johan
Hi,
looks good, ack from me.
Acked-by: Jukka Rissanen <[email protected]>
On Wed, 2016-01-13 at 16:41 +0100, Glenn Ruben Bakke wrote:
> The fixes provided in this patch assigns a valid net_device structure
> to
> skb before dispatching it for further processing.
>
> Scenario #1:
> ============
>
> Bluetooth 6lowpan receives an uncompressed IPv6 header, and
> dispatches it
> to netif. The following error occurs:
>
> Null pointer dereference error #1 crash log:
>
> [ 845.854013] BUG: unable to handle kernel NULL pointer dereference
> at
> 0000000000000048
> [ 845.855785] IP: [<ffffffff816e3d36>] enqueue_to_backlog+0x56/0x240
> ...
> [ 845.909459] Call Trace:
> [ 845.911678] [<ffffffff816e3f64>] netif_rx_internal+0x44/0xf0
>
> The first modification fixes the NULL pointer dereference error by
> assigning dev to the local_skb in order to set a valid net_device
> before
> processing the skb by netif_rx_ni().
>
> Scenario #2:
> ============
>
> Bluetooth 6lowpan receives an UDP compressed message which needs
> further
> decompression by nhc_udp. The following error occurs:
>
> Null pointer dereference error #2 crash log:
>
> [ 63.295149] BUG: unable to handle kernel NULL pointer dereference
> at
> 0000000000000840
> [ 63.295931] IP: [<ffffffffc0559540>] udp_uncompress+0x320/0x626
> [nhc_udp]
>
> The second modification fixes the NULL pointer dereference error by
> assigning dev to the local_skb in the case of a udp compressed
> packet.
> The 6lowpan udp_uncompress function expects that the net_device is
> set in
> the skb when checking lltype.
>
> Signed-off-by: Glenn Ruben Bakke <[email protected]>
> Signed-off-by: Lukasz Duda <[email protected]>
> ---
> net/bluetooth/6lowpan.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
> index d040365..58e1b3c 100644
> --- a/net/bluetooth/6lowpan.c
> +++ b/net/bluetooth/6lowpan.c
> @@ -317,6 +317,7 @@ static int recv_pkt(struct sk_buff *skb, struct
> net_device *dev,
>
> local_skb->protocol = htons(ETH_P_IPV6);
> local_skb->pkt_type = PACKET_HOST;
> + local_skb->dev = dev;
>
> skb_set_transport_header(local_skb, sizeof(struct
> ipv6hdr));
>
> @@ -335,6 +336,8 @@ static int recv_pkt(struct sk_buff *skb, struct
> net_device *dev,
> if (!local_skb)
> goto drop;
>
> + local_skb->dev = dev;
> +
> ret = iphc_decompress(local_skb, dev, chan);
> if (ret < 0) {
> kfree_skb(local_skb);
> @@ -343,7 +346,6 @@ static int recv_pkt(struct sk_buff *skb, struct
> net_device *dev,
>
> local_skb->protocol = htons(ETH_P_IPV6);
> local_skb->pkt_type = PACKET_HOST;
> - local_skb->dev = dev;
>
> if (give_skb_to_upper(local_skb, dev)
> != NET_RX_SUCCESS) {
Cheers,
Jukka