Re: [syzbot] UBSAN: shift-out-of-bounds in xfrm_set_default

[Pavel Skripkin]

 On Tue, 27 Jul 2021 05:47:21 -0700
syzbot <syzbot+9cd5837a045bbee5b810@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    90d856e71443 Add linux-next specific files for
> 20210723 git tree:       linux-next
> console output:
> https://syzkaller.appspot.com/x/log.txt?x=133fd00a300000 kernel
> config:  https://syzkaller.appspot.com/x/.config?x=298516715f6ad5cd
> dashboard link:
> https://syzkaller.appspot.com/bug?extid=9cd5837a045bbee5b810
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU
> Binutils for Debian) 2.35.1 syz repro:
> https://syzkaller.appspot.com/x/repro.syz?x=1263bba6300000 C
> reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1066b4d4300000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the
> commit: Reported-by:
> syzbot+9cd5837a045bbee5b810@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> netlink: 228 bytes leftover after parsing attributes in process
> `syz-executor669'.
> ================================================================================


The first thing that comes in mind is to check up->dirmask value


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


With regards,
Pavel Skripkin