linux-kernel - Re: [PATCH] kasan: report only the first error

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 22 Mar 2017 19:54:17 +0300
From:   Andrey Ryabinin <aryabinin@...tuozzo.com>
To:     Andrey Konovalov <andreyknvl@...gle.com>
CC:     Andrew Morton <akpm@...ux-foundation.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Potapenko <glider@...gle.com>,
        "Dmitry Vyukov" <dvyukov@...gle.com>,
        kasan-dev <kasan-dev@...glegroups.com>,
        "Linux Memory Management List" <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] kasan: report only the first error

On 03/22/2017 07:34 PM, Andrey Konovalov wrote:
> On Wed, Mar 22, 2017 at 5:06 PM, Andrey Ryabinin
> <aryabinin@...tuozzo.com> wrote:
>> Disable kasan after the first report. There are several reasons for this:
>>  * Single bug quite often has multiple invalid memory accesses causing
>>     storm in the dmesg.
>>  * Write OOB access might corrupt metadata so the next report will print
>>     bogus alloc/free stacktraces.
>>  * Reports after the first easily could be not bugs by itself but just side
>>     effects of the first one.
>>
>> Given that multiple reports only do harm, it makes sense to disable
>> kasan after the first one. Except for the tests in lib/test_kasan.c
>> as we obviously want to see all reports from test.
> 
> Hi Andrey,
> 
> Could you make it configurable via CONFIG_KASAN_SOMETHING (which can
> default to showing only the first report)?

I'd rather make this boot time configurable, but wouldn't want to without
a good reason.


> I sometimes use KASAN to see what bad accesses a particular bug
> causes, and seeing all of them (even knowing that they may be
> corrupt/induced) helps a lot.

I'm wondering why you need to see all reports?

> 
> Thanks!
>