From: "Tobin C. Harding" <me@tobin.cc>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Kees Cook <keescook@chromium.org>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Linux-MM <linux-mm@kvack.org>,
syzbot
<bot+719398b443fd30155f92f2a888e749026c62b427@syzkaller.appspotmail.com>,
David Windsor <dave@nullcore.net>,
keun-o.park@darkmatter.ae, Laura Abbott <labbott@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Ingo Molnar <mingo@kernel.org>,
syzkaller-bugs@googlegroups.com,
Will Deacon <will.deacon@arm.com>
Subject: Re: BUG: bad usercopy in memdup_user
Date: Tue, 19 Dec 2017 19:37:46 +1100 [thread overview]
Message-ID: <20171219083746.GR19604@eros> (raw)
In-Reply-To: <CACT4Y+a3h0hmGpfVaePX53QUQwBhN9BUyERp-5HySn74ee_Vxw@mail.gmail.com>
On Tue, Dec 19, 2017 at 09:12:58AM +0100, Dmitry Vyukov wrote:
> On Tue, Dec 19, 2017 at 1:57 AM, Kees Cook <keescook@chromium.org> wrote:
> > On Mon, Dec 18, 2017 at 6:22 AM, Tetsuo Handa
> > <penguin-kernel@i-love.sakura.ne.jp> wrote:
> >> On 2017/12/18 22:40, syzbot wrote:
> >>> Hello,
> >>>
> >>> syzkaller hit the following crash on 6084b576dca2e898f5c101baef151f7bfdbb606d
> >>> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
> >>> compiler: gcc (GCC) 7.1.1 20170620
> >>> .config is attached
> >>> Raw console output is attached.
> >>>
> >>> Unfortunately, I don't have any reproducer for this bug yet.
> >>>
> >>>
> >>
> >> This BUG is reporting
> >>
> >> [ 26.089789] usercopy: kernel memory overwrite attempt detected to 0000000022a5b430 (kmalloc-1024) (1024 bytes)
> >>
> >> line. But isn't 0000000022a5b430 strange for kmalloc(1024, GFP_KERNEL)ed kernel address?
> >
> > The address is hashed (see the %p threads for 4.15).
>
>
> +Tobin, is there a way to disable hashing entirely? The only
> designation of syzbot is providing crash reports to kernel developers
> with as much info as possible. It's fine for it to leak whatever.
We have new specifier %px to print addresses in hex if leaking info is
not a worry.
Hope this helps,
Tobin.
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next prev parent reply other threads:[~2017-12-19 8:37 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-18 13:40 syzbot
2017-12-18 14:22 ` Tetsuo Handa
2017-12-19 0:57 ` Kees Cook
2017-12-19 8:12 ` Dmitry Vyukov
2017-12-19 8:37 ` Tobin C. Harding [this message]
2017-12-19 8:41 ` Dmitry Vyukov
2017-12-19 9:04 ` Tobin C. Harding
2017-12-19 9:07 ` Dmitry Vyukov
2017-12-19 13:22 ` Matthew Wilcox
2017-12-19 13:41 ` Dmitry Vyukov
2017-12-19 14:08 ` Tetsuo Handa
2017-12-19 14:12 ` Dmitry Vyukov
2017-12-19 20:45 ` Tobin C. Harding
2017-12-19 20:33 ` Tobin C. Harding
2017-12-19 21:36 ` Linus Torvalds
2017-12-19 21:48 ` Al Viro
2017-12-19 22:09 ` Randy Dunlap
2017-12-19 23:24 ` Linus Torvalds
2017-12-20 3:50 ` Matthew Wilcox
2017-12-20 4:05 ` Linus Torvalds
2017-12-20 4:36 ` Linus Torvalds
2017-12-20 9:44 ` David Laight
2017-12-31 8:11 ` Dmitry Vyukov
2017-12-19 21:54 ` Kees Cook
2017-12-19 22:16 ` Matthew Wilcox
2017-12-19 22:24 ` Laura Abbott
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