On Fri, Jan 4, 2019 at 12:14 PM Stefano Brivio <sbri...@redhat.com> wrote: > > On Fri, 4 Jan 2019 12:05:04 +0100 > Dmitry Vyukov <dvyu...@google.com> wrote: > > > On Fri, Jan 4, 2019 at 11:54 AM Stefano Brivio <sbri...@redhat.com> wrote: > > > > > > On Fri, 4 Jan 2019 11:32:12 +0100 > > > Dmitry Vyukov <dvyu...@google.com> wrote: > > > > > > > On Thu, Jan 3, 2019 at 10:54 PM Stefano Brivio <sbri...@redhat.com> > > > > wrote: > > > > > > > > > > On Thu, 3 Jan 2019 15:15:06 -0600 > > > > > Willem de Bruijn <willemdebruijn.ker...@gmail.com> wrote: > > > > > > > > > > > syzbot generated stack traces with > > > > > > > > > > > > [ 183.517380] udpv6_err+0x46/0x60 > > > > > > [ 183.520739] ? __udp6_lib_err+0x1890/0x1890 > > > > > > [ 183.525054] gue6_err_proto_handler+0x199/0x280 > > > > > > > > > > Where? I can't find that in any logs linked from the dashboard at > > > > > https://syzkaller.appspot.com/bug?extid=4ad25edc7a33e4ab91e0 :( > > > > > > > > Stefano, there are these 4 bugs reported that have similarly looking > > > > reproducers involving udp sockets and that crash modes that looks like > > > > stack corruption/overflow: > > > > > > > > https://syzkaller.appspot.com/bug?extid=14005fa30c9a07192934 > > > > https://syzkaller.appspot.com/bug?extid=d14090007dc9ba5fa9b7 > > > > https://syzkaller.appspot.com/bug?extid=137ed32ec9a6d5b0d5fe > > > > https://syzkaller.appspot.com/bug?id=d5bc3e0c66d200d72216ab343a67c4327e4a3452 > > > > > > > > Are these the same bug as this? > > > > > > Judging from the reproducers for the first three, they seem to be. > > > > OK, then I will mark them as dups of this one. > > syzbot just finished the tests I requested and couldn't reproduce the > first three issues with the fix I posted (fou6: Prevent unbounded > recursion in GUE error handler).
Thanks for preparing the fixes so quickly, Stefano. I also noticed one trace that seemingly goes through an ip6erspan tunnel as well as gue6. [ 760.618683] ? __udp6_lib_err+0xcb/0x640 [ 760.622716] ? udplitev6_err+0x46/0x60 [ 760.626573] ? gue6_err+0x105/0x270 [ 760.630170] ? udp_lib_close+0x20/0x20 [ 760.634027] ? ip6erspan_tunnel_xmit+0xdc0/0xdc0 Without knowing the err_handler code too well: is it possible that packets with an intermediate IPIP or other tunnel still bypass the checks (which check for strictly UDP in GUE)?
