Messages in this thread | | | Subject | Re: [PATCH] 6lowpan: iphc: reset mac_header after decompress to fix panic | From | Marcel Holtmann <> | Date | Fri, 6 Jul 2018 12:46:20 +0200 |
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Hi Michael,
> After decompression of 6lowpan socket data, an IPv6 header is inserted > before the existing socket payload. After this, we reset the > network_header value of the skb to account for the difference in payload > size from prior to decompression + the addition of the IPv6 header. > > However, we fail to reset the mac_header value. > > Leaving the mac_header value untouched here, can cause a calculation > error in net/packet/af_packet.c packet_rcv() function when an > AF_PACKET socket is opened in SOCK_RAW mode for use on a 6lowpan > interface. > > On line 2088, the data pointer is moved backward by the value returned > from skb_mac_header(). If skb->data is adjusted so that it is before > the skb->head pointer (which can happen when an old value of mac_header > is left in place) the kernel generates a panic in net/core/skbuff.c > line 1717. > > This panic can be generated by BLE 6lowpan interfaces (such as bt0) and > 802.15.4 interfaces (such as lowpan0) as they both use the same 6lowpan > sources for compression and decompression. > > Signed-off-by: Michael Scott <michael@opensourcefoundries.com> > --- > net/6lowpan/iphc.c | 1 + > 1 file changed, 1 insertion(+)
patch has been applied to bluetooth-next tree.
Regards
Marcel
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