Re: [syzbot] KMSAN: kernel-usb-infoleak in usbnet_write_cmd (3)

[Alexander Potapenko]

On Thu, Jan 6, 2022 at 11:17 PM Pavel Skripkin <paskripkin@xxxxxxxxx> wrote:
>
> On 1/5/22 21:28, syzbot wrote:
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    81c325bbf94e kmsan: hooks: do not check memory in kmsan_in..
> > git tree:       https://github.com/google/kmsan.git master
> > console output: https://syzkaller.appspot.com/x/log.txt?x=14a07163b00000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=2d8b9a11641dc9aa
> > dashboard link: https://syzkaller.appspot.com/bug?extid=003c0a286b9af5412510
> > compiler:       clang version 14.0.0 (/usr/local/google/src/llvm-git-monorepo 2b554920f11c8b763cd9ed9003f4e19b919b8e1f), GNU ld (GNU Binutils for Debian) 2.35.2
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=100165dbb00000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10c97e77b00000
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+003c0a286b9af5412510@xxxxxxxxxxxxxxxxxxxxxxxxx
> >
>
> Heh, I think, more reports like this will appear soon. Syzbot learned
> how to tweak usb read functions return values, I guess?

This has been possible long ago. I think these new reports are related
to fresh KMSAN changes (and also the fact KMSAN was broken for a while
last year, and is now catching up).

> #syz test: https://github.com/google/kmsan.git master
>
>
>
> With regards,
> Pavel Skripkin



-- 
Alexander Potapenko
Software Engineer

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