From: Roman Penyaev <rpenyaev@suse.de>
To: Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Joe Perches <joe@perches.com>,
"Luis R. Rodriguez" <mcgrof@kernel.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH 1/3] mm/vmalloc: fix size check for remap_vmalloc_range_partial()
Date: Fri, 04 Jan 2019 11:21:39 +0100 [thread overview]
Message-ID: <4630dd7797fc7934f98c01ea789105a8@suse.de> (raw)
In-Reply-To: <20190104093808.GJ31793@dhcp22.suse.cz>
On 2019-01-04 10:38, Michal Hocko wrote:
[...]
>> >
>> > OK, my response was more confusing than I intended. I meant to say. Is
>> > there any in kernel code that would allow the bug have had in mind?
>> > In other words can userspace trick any existing code?
>>
>> In theory any existing caller of remap_vmalloc_range() which does
>> not have an explicit size check should trigger an oops, e.g. this is
>> a good candidate:
>>
>> *** drivers/media/usb/stkwebcam/stk-webcam.c:
>> v4l_stk_mmap[789] ret = remap_vmalloc_range(vma,
>> sbuf->buffer,
>> 0);
>
> Hmm, sbuf->buffer is allocated in stk_setup_siobuf to have
> buf->v4lbuf.length. mmap callback maps this buffer to the vma size and
> that is indeed not enforced to be <= length AFAICS. So you are right!
>
> Can we have an example in the changelog please?
You mean to resend this particular patch with the list of possible
candidates for oops in a comment message? Sure thing.
--
Roman
next prev parent reply other threads:[~2019-01-04 10:21 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190103145954.16942-1-rpenyaev@suse.de>
2019-01-03 14:59 ` [PATCH 1/3] mm/vmalloc: fix size check for remap_vmalloc_range_partial() Roman Penyaev
2019-01-03 15:13 ` Michal Hocko
2019-01-03 19:27 ` Roman Penyaev
2019-01-03 19:40 ` Michal Hocko
2019-01-03 20:31 ` Roman Penyaev
2019-01-04 9:38 ` Michal Hocko
2019-01-04 10:21 ` Roman Penyaev [this message]
2019-01-04 10:28 ` Michal Hocko
2019-01-03 19:59 ` Michal Hocko
2019-01-04 11:06 ` Roman Penyaev
2019-01-11 19:19 ` Andrey Ryabinin
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