From: Yuri Gribov <tetra2005@gmail.com>
To: Zack Weinberg <zackw@panix.com>
Cc: Kostya Serebryany <kcc@google.com>,
Maxim Ostapenko <m.ostapenko@samsung.com>,
GNU C Library <libc-alpha@sourceware.org>,
Florian Weimer <fweimer@redhat.com>
Subject: Re: [PATCH BZ#20422] Do not allow asan/msan/tsan and fortify at the same time.
Date: Wed, 05 Oct 2016 17:58:00 -0000 [thread overview]
Message-ID: <CAJOtW+7AhKGJxwjhhF3H=uHRr0WKU=1Sr8vrMALBAe7SnXpKJw@mail.gmail.com> (raw)
In-Reply-To: <CAKCAbMhXmCOOJp=eoxUzEmY=ik3oKsN9QrXYrsX61ocDZ2gnhw@mail.gmail.com>
On Wed, Oct 5, 2016 at 5:46 PM, Zack Weinberg <zackw@panix.com> wrote:
> On Wed, Oct 5, 2016 at 12:10 PM, Kostya Serebryany <kcc@google.com> wrote:
>> On Wed, Oct 5, 2016 at 9:06 AM, Zack Weinberg <zackw@panix.com> wrote:
>>> On Mon, Sep 5, 2016 at 1:27 PM, Maxim Ostapenko <m.ostapenko@samsung.com> wrote:
>>>> When fortify is used with MSan it will cause MSan false positives.
>>> ... appears to me to be a plain old bug. Either the fortify shims are
>>> actually using an uninitialized value, in which case they should be
>>> fixed, or MSan has misunderstood the code generated in _FORTIFY_SOURCE
>>> mode, in which case MSan should be fixed.
>>>
>>> You understand what is going on better than anyone else here, I think
>>> - can you please write up a detailed description of exactly why this
>>> goes wrong?
>>
>> * fortify replaces sprintf with sprintf_chk
>> * msan does not know about sprintf_chk
>> * sprintf_chk initializes 'text' but msan does not know that
>
> OK, that's the bug right there, msan should know that.
>
> Why is it hard to fix that bug? Why are we instead arguing over
> whether we should prevent people from enabling both defensive measures
> at the same time?
Not that it's hard, rather what's the appropriate place to fix it. I
think the discussion has mostly died out so there is no point keep it
going.
> zw
prev parent reply other threads:[~2016-10-05 17:58 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-05 17:27 Maxim Ostapenko
2016-09-05 19:48 ` Andrew Pinski
2016-09-06 8:39 ` Florian Weimer
2016-09-06 8:58 ` Yuri Gribov
2016-09-06 9:13 ` Florian Weimer
2016-09-06 9:20 ` Yuri Gribov
2016-09-06 9:51 ` Florian Weimer
2016-09-09 22:35 ` Kostya Serebryany
[not found] ` <CAN=P9phe_OP+tU+nnDDPEeZCR77w2ddrSX+LtSnx2-42p9JgUg@mail.gmail.com>
2016-09-12 9:36 ` Florian Weimer
2016-09-06 9:16 ` Maxim Ostapenko
2016-09-06 9:44 ` Florian Weimer
2016-09-09 22:36 ` Kostya Serebryany
2016-09-12 9:31 ` Florian Weimer
2016-09-12 18:54 ` Kostya Serebryany
2016-09-17 9:00 ` Yuri Gribov
2016-09-29 8:08 ` Florian Weimer
2016-09-29 9:47 ` Yuri Gribov
2016-09-29 10:04 ` Jakub Jelinek
2016-09-29 10:32 ` Yuri Gribov
2016-09-29 10:44 ` Jakub Jelinek
2016-09-29 10:52 ` Andrew Pinski
2016-09-29 21:23 ` Kostya Serebryany
2016-10-01 21:38 ` Andrew Pinski
2016-10-01 21:50 ` Jakub Jelinek
2016-10-02 7:51 ` Florian Weimer
2016-10-02 9:40 ` Jakub Jelinek
2016-10-02 9:43 ` Florian Weimer
2016-10-02 14:02 ` Yuri Gribov
2016-10-04 0:53 ` Kostya Serebryany
2016-10-04 6:46 ` Jakub Jelinek
2016-10-04 12:15 ` fortification and valgrind/memcheck (Was: [PATCH BZ#20422] Do not allow asan/msan/tsan and fortify@the same time) Mark Wielaard
2016-10-05 11:49 ` Florian Weimer
2016-10-05 12:02 ` Mark Wielaard
2016-10-05 14:27 ` [PATCH BZ#20422] Do not allow asan/msan/tsan and fortify at the same time Florian Weimer
2016-10-05 15:46 ` Maxim Ostapenko
2016-10-05 16:01 ` Maxim Ostapenko
2016-10-05 16:01 ` Kostya Serebryany
2016-10-05 16:06 ` Zack Weinberg
2016-10-05 16:11 ` Kostya Serebryany
2016-10-05 16:46 ` Zack Weinberg
2016-10-05 17:58 ` Yuri Gribov [this message]
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