From: Greg KH <gregkh@linuxfoundation.org>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: syzbot <syzbot+a7e220df5a81d1ab400e@syzkaller.appspotmail.com>,
Andrey Konovalov <andreyknvl@google.com>,
balbi@kernel.org, Dan Carpenter <dan.carpenter@oracle.com>,
Alexander Potapenko <glider@google.com>,
LKML <linux-kernel@vger.kernel.org>,
USB list <linux-usb@vger.kernel.org>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Subject: Re: KMSAN: kernel-infoleak in raw_ioctl
Date: Mon, 10 Aug 2020 11:08:33 +0200 [thread overview]
Message-ID: <20200810090833.GA2271719@kroah.com> (raw)
In-Reply-To: <CACT4Y+aS6oangE4BzhCfx3gs9guAW=zQpwN1LP+yB3kza68xFw@mail.gmail.com>
On Mon, Aug 10, 2020 at 11:00:07AM +0200, Dmitry Vyukov wrote:
> On Mon, Aug 10, 2020 at 9:46 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > On Sun, Aug 09, 2020 at 09:27:18AM -0700, syzbot wrote:
> > > Hello,
> > >
> > > syzbot found the following issue on:
> > >
> > > HEAD commit: ce8056d1 wip: changed copy_from_user where instrumented
> > > git tree: https://github.com/google/kmsan.git master
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=141eb8b2900000
> > > kernel config: https://syzkaller.appspot.com/x/.config?x=3afe005fb99591f
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=a7e220df5a81d1ab400e
> > > compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
> > > userspace arch: i386
> > >
> > > Unfortunately, I don't have any reproducer for this issue yet.
> >
> > The irony of a kernel module written for syzbot testing, causing syzbot
> > reports....
>
> The raw gadget and KCOV are also kernel code and subject to all the
> same rules as any other kernel code from syzkaller point of view.
>
> But I think the root cause of this bug is the origin of the uninitialized-ness:
>
> Local variable ----buf.i@asix_get_phy_addr created at:
> asix_read_cmd drivers/net/usb/asix_common.c:312 [inline]
> asix_read_phy_addr drivers/net/usb/asix_common.c:295 [inline]
> asix_get_phy_addr+0x4d/0x290 drivers/net/usb/asix_common.c:314
> asix_read_cmd drivers/net/usb/asix_common.c:312 [inline]
> asix_read_phy_addr drivers/net/usb/asix_common.c:295 [inline]
> asix_get_phy_addr+0x4d/0x290 drivers/net/usb/asix_common.c:314
read buffers sent to USB hardware are ment to be filled in by the
hardware with the data received from it, we do not zero-out those
buffers before passing the pointer there.
Perhaps with testing frameworks like the raw usb controller, that might
cause a number of false-positives to happen?
thanks,
greg k-h
next prev parent reply other threads:[~2020-08-10 9:08 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-09 16:27 KMSAN: kernel-infoleak in raw_ioctl syzbot
2020-08-10 7:47 ` Greg KH
2020-08-10 9:00 ` Dmitry Vyukov
2020-08-10 9:08 ` Greg KH [this message]
2020-08-10 9:15 ` Greg KH
2020-08-10 9:57 ` Greg KH
2020-08-10 10:21 ` Dmitry Vyukov
2020-08-10 11:06 ` Greg KH
2020-08-10 14:07 ` Andrey Konovalov
2020-08-10 14:17 ` Dmitry Vyukov
2020-08-19 6:33 ` syzbot
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