Re: net/sctp: use-after-free in __sctp_connect

[Andrey Konovalov]

On Wed, Oct 19, 2016 at 6:57 PM, Marcelo Ricardo Leitner
<marcelo.leitner@xxxxxxxxx> wrote:
> On Wed, Oct 19, 2016 at 02:25:24PM +0200, Andrey Konovalov wrote:
>> Hi,
>>
>> I've got the following error report while running the syzkaller fuzzer:
>>
>> ==================================================================
>> BUG: KASAN: use-after-free in __sctp_connect+0xabe/0xbf0 at addr
>> ffff88006b1dc610
>
> Seems this is the same that Dmitry Vyukov had reported back in Jan 13th.
> So far I couldn't identify the reason.
> "Good" to know it's still there, thanks for reporting it.

Hi Marcelo,

I've attached a reproducer that might help to figure out the reason.

It triggers the UAF for me in ~10 seconds of running as:
$ gcc -lpthread sctp-connect-uaf-poc.c
$ while true; do ./a.out; done

You need to have KASAN enabled.

>

Attachment: sctp-connect-uaf-poc.c
Description: Binary data