Re: KASAN: slab-out-of-bounds Read in bpf_skb_vlan_push

[Daniel Borkmann]

On 06/13/2018 08:13 PM, syzbot wrote:
>> On 06/13/2018 06:17 PM, syzbot wrote:
>>> Hello,
> 
>>> syzbot found the following crash on:
> 
>>> HEAD commit:ÂÂÂ 75d4e704fa8d netdev-FAQ: clarify DaveM's position for stab..
>>> git tree:ÂÂÂÂÂÂ bpf-next
>>> console output: https://syzkaller.appspot.com/x/log.txt?x=1754783f800000
>>> kernel config:Â https://syzkaller.appspot.com/x/.config?x=a601a80fec461d44
>>> dashboard link: https://syzkaller.appspot.com/bug?extid=76de61614cb1abdd73fc
>>> compiler:ÂÂÂÂÂÂ gcc (GCC) 8.0.1 20180413 (experimental)
>>> syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=12c1e1bf800000
> 
>>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>>> Reported-by: syzbot+76de61614cb1abdd73fc@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
>>> IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready
>>> IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
>>> 8021q: adding VLAN 0 to HW filter on device team0
>>> 8021q: adding VLAN 0 to HW filter on device team0
>>> ==================================================================
>>> BUG: KASAN: slab-out-of-bounds in skb_at_tc_ingress include/net/sch_generic.h:535 [inline]
>>> BUG: KASAN: slab-out-of-bounds in bpf_push_mac_rcsum net/core/filter.c:1625 [inline]
>>> BUG: KASAN: slab-out-of-bounds in ____bpf_skb_vlan_push net/core/filter.c:2446 [inline]
>>> BUG: KASAN: slab-out-of-bounds in bpf_skb_vlan_push+0x6b7/0x720 net/core/filter.c:2437
>>> Read of size 5 at addr ffff8801b77347d0 by task syz-executor6/6529
> 
>> Should be fixed already by:
> 
>> ÂÂ https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=58990d1ff3f7896ee341030e9a7c2e4002570683
> 
> 
>> #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> 
> want 2 args (repo, branch), got 1

Fair enough ... assumed default would have been master. ;-)

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master