Re: [syzbot] WARNING in ovl_fh_to_dentry

[Kees Cook]

On Fri, Sep 23, 2022 at 09:05:40AM -0700, syzbot wrote:
> syzbot found the following issue on:
> 
> HEAD commit:    483fed3b5dc8 Add linux-next specific files for 20220921
> git tree:       linux-next
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=13b13f30880000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=849cb9f70f15b1ba
> dashboard link: https://syzkaller.appspot.com/bug?extid=9d14351a171d0d1c7955
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14283ac4880000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=156da4ef080000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/1cb3f4618323/disk-483fed3b.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/cc02cb30b495/vmlinux-483fed3b.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+9d14351a171d0d1c7955@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> ------------[ cut here ]------------
> memcpy: detected field-spanning write (size 93) of single field "&fh->fb" at fs/overlayfs/export.c:799 (size 21)

I've send a patch for this now:
https://lore.kernel.org/linux-hardening/20220924073315.3593031-1-keescook@xxxxxxxxxxxx

-- 
Kees Cook