Bluetooth: 6lowpan: Fix kernel NULL pointer dereferences
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 <glenn.ruben.bakke@nordicsemi.no>
Signed-off-by: Lukasz Duda <lukasz.duda@nordicsemi.no>
Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Cc: stable@vger.kernel.org # 4.4+
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 @@
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 @@
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 @@
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) {