netdev - Re: [PATCH net] vsock/bpf: Handle EINTR connect() racing against sockmap update

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Message-ID: <20250311162304.5xcnjeue2uwrhswg@gmail.com>
Date: Tue, 11 Mar 2025 09:23:04 -0700
From: John Fastabend <john.fastabend@...il.com>
To: Michal Luczaj <mhal@...x.co>
Cc: Stefano Garzarella <sgarzare@...hat.com>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Simon Horman <horms@...nel.org>,
	Bobby Eshleman <bobby.eshleman@...edance.com>,
	"Michael S. Tsirkin" <mst@...hat.com>, netdev@...r.kernel.org,
	bpf@...r.kernel.org
Subject: Re: [PATCH net] vsock/bpf: Handle EINTR connect() racing against
 sockmap update

On 2025-03-07 10:27:50, Michal Luczaj wrote:
> Signal delivered during connect() may result in a disconnect of an already
> TCP_ESTABLISHED socket. Problem is that such established socket might have
> been placed in a sockmap before the connection was closed. We end up with a
> SS_UNCONNECTED vsock in a sockmap. And this, combined with the ability to
> reassign (unconnected) vsock's transport to NULL, breaks the sockmap
> contract. As manifested by WARN_ON_ONCE.
> 
> Ensure the socket does not stay in sockmap.
> 
> WARNING: CPU: 10 PID: 1310 at net/vmw_vsock/vsock_bpf.c:90 vsock_bpf_recvmsg+0xb4b/0xdf0
> CPU: 10 UID: 0 PID: 1310 Comm: a.out Tainted: G        W          6.14.0-rc4+
>  sock_recvmsg+0x1b2/0x220
>  __sys_recvfrom+0x190/0x270
>  __x64_sys_recvfrom+0xdc/0x1b0
>  do_syscall_64+0x93/0x1b0
>  entry_SYSCALL_64_after_hwframe+0x76/0x7e
> 
> Fixes: 634f1a7110b4 ("vsock: support sockmap")
> Signed-off-by: Michal Luczaj <mhal@...x.co>

Hi Michal,

Unhashing the socket to stop any references from sockmap side if the
sock is being put into CLOSING state makes sense to me. Was there
another v2 somewhere? I didn't see it in my inbox or I missed it.
I think you mentioned more fixes were needed.

Thanks!
John