linux-kernel - Re: [PATCH net-next v4] vsock/test: Add test for null ptr deref when transport changes

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]

Message-ID: <brnvavvmkbxcvzy6ahwyissqnmjl7db2w6yfk5pmipuhuvsdu4@qwoeyioaues6>
Date: Wed, 9 Jul 2025 16:57:09 +0200
From: Luigi Leonardi <leonardi@...hat.com>
To: Konstantin Shkolnyy <kshk@...ux.ibm.com>
Cc: mhal@...x.co, sgarzare@...hat.com, virtualization@...ts.linux.dev, 
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org, v4bel@...ori.io
Subject: Re: [PATCH net-next v4] vsock/test: Add test for null ptr deref when
 transport changes

Hi Konstantin,

On Wed, Jul 09, 2025 at 09:54:03AM -0500, Konstantin Shkolnyy wrote:
>I'm seeing a problem on s390 with the new "SOCK_STREAM transport 
>change null-ptr-deref" test. Here is how it appears to happen:
>
>test_stream_transport_change_client() spins for 2s and sends 70K+ 
>CONTROL_CONTINUE messages to the "control" socket.
>
>test_stream_transport_change_server() spins calling accept() because 
>it keeps receiving CONTROL_CONTINUE.
>
>When the client exits, the server has received just under 1K of those 
>70K CONTROL_CONTINUE, so it calls accept() again but the client has 
>exited, so accept() never returns and the server never exits.
>

Thanks for pointing this out!
I had an offline discussion with Stefano about this issue.
This patch[1] should address it.
Please let us know if it works on s390 too.

Cheers,
Luigi

[1]https://lore.kernel.org/netdev/20250708111701.129585-1-sgarzare@redhat.com/