RE: KMSAN: uninit-value in __inet6_bind

[Jon Maloy]

> -----Original Message-----
> From: netdev-owner@xxxxxxxxxxxxxxx <netdev-owner@xxxxxxxxxxxxxxx>
> On Behalf Of Eric Dumazet
> Sent: 14-Dec-18 10:15
> To: Jon Maloy <jon.maloy@xxxxxxxxxxxx>; Cong Wang
> <xiyou.wangcong@xxxxxxxxx>; Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> Cc: syzbot+c56449ed3652e6720f30@xxxxxxxxxxxxxxxxxxxxxxxxx; Ying Xue
> <ying.xue@xxxxxxxxxxxxx>; tipc-discussion@xxxxxxxxxxxxxxxxxxxxx; David
> Miller <davem@xxxxxxxxxxxxx>; Alexey Kuznetsov <kuznet@xxxxxxxxxxxxx>;
> LKML <linux-kernel@xxxxxxxxxxxxxxx>; Linux Kernel Network Developers
> <netdev@xxxxxxxxxxxxxxx>; syzkaller-bugs@xxxxxxxxxxxxxxxx; Hideaki
> YOSHIFUJI <yoshfuji@xxxxxxxxxxxxxx>
> Subject: Re: KMSAN: uninit-value in __inet6_bind
> 
> 
> 
> On 12/14/2018 07:04 AM, Jon Maloy wrote:
> >
> >
> >> -----Original Message-----
> >> From: Cong Wang <xiyou.wangcong@xxxxxxxxx>
> >> Sent: 12-Dec-18 01:17
> >> To: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> >> Cc: syzbot+c56449ed3652e6720f30@xxxxxxxxxxxxxxxxxxxxxxxxx; Jon
> Maloy
> >> <jon.maloy@xxxxxxxxxxxx>; Ying Xue <ying.xue@xxxxxxxxxxxxx>; tipc-
> >> discussion@xxxxxxxxxxxxxxxxxxxxx; David Miller <davem@xxxxxxxxxxxxx>;
> >> Alexey Kuznetsov <kuznet@xxxxxxxxxxxxx>; LKML <linux-
> >> kernel@xxxxxxxxxxxxxxx>; Linux Kernel Network Developers
> >> <netdev@xxxxxxxxxxxxxxx>; syzkaller-bugs@xxxxxxxxxxxxxxxx; Hideaki
> >> YOSHIFUJI <yoshfuji@xxxxxxxxxxxxxx>
> >> Subject: Re: KMSAN: uninit-value in __inet6_bind
> >>
> >> On Tue, Dec 11, 2018 at 1:04 AM Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> >> wrote:
> >>>
> >>> On Tue, Dec 11, 2018 at 1:41 AM syzbot
> >>> <syzbot+c56449ed3652e6720f30@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> >>>>
> >>>> Hello,
> >>>>
> >>>> syzbot found the following crash on:
> >>>>
> >>>> HEAD commit:    3f06bda61398 kmsan: remove excessive KMSAN
> >> wrappers from a..
> >>>> git tree:       https://github.com/google/kmsan.git/master
> >>>> console output:
> >>>> https://syzkaller.appspot.com/x/log.txt?x=13ca6b05400000
> >>>> kernel config:
> >>>> https://syzkaller.appspot.com/x/.config?x=9b071100dcf8e641
> >>>> dashboard link:
> >> https://syzkaller.appspot.com/bug?extid=c56449ed3652e6720f30
> >>>> compiler:       clang version 8.0.0 (trunk 348261)
> >>>>
> >>>> Unfortunately, I don't have any reproducer for this crash yet.
> >>>>
> >>>> IMPORTANT: if you fix the bug, please add the following tag to the
> >> commit:
> >>>> Reported-by:
> syzbot+c56449ed3652e6720f30@xxxxxxxxxxxxxxxxxxxxxxxxx
> >>>
> >>> This looks like a bug in TIPC, +TIPC maintainers.
> >>>
> >>
> >> It looks more like udp_sock_create6() doesn't initialize
> >> udp6_addr.sin6_scope_id.
> >
> > Unfortunately udp_sock_create6() has no way of knowing this value,
> because struct udp_port_cfg is missing a field sin6_scope_id.
> > So this has to be fixed first by adding this field to the struct, and then
> setting it correctly in all current users.
> >
> 
> Do we reasons to believe values other than 0 are needed ?
> 
For TIPC it is ok with 0.

///jon