Re: [PATCH] vsock/vmci: reject datagram binds in local network namespaces

[sashiko-bot@kernel.org]

> VMCI already rejects datagram sends from local network namespaces, but a
> datagram bind still creates a receive handle in VMCI's global port space.
> A VMCI sender outside the namespace can therefore deliver to the local
> socket. Its handle also prevents a global-namespace socket from binding
> the same port.
> 
> Reject VMCI datagram binds in local namespaces. No namespace-local
> datagram transport exists, so EOPNOTSUPP reflects the available receive
> paths. The receive callback also rejects any local-mode socket as a
> defensive check.
> 
> In a KASAN/lockdep QEMU guest, a reproducer observed cross-namespace
> delivery and the global port collision before the fix. After the fix,
> local bind returns EOPNOTSUPP, the global bind succeeds, and a global
> VMCI datagram still reaches the global socket.
> 
> Fixes: eafb64f40ca4 ("vsock: add netns to vsock core")
> Cc: stable@vger.kernel.org
> Link: https://lore.kernel.org/all/sashiko-outbox-212907@kernel.org/
> Signed-off-by: Sergio Lopez <slp@redhat.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261113-vsock-vmci-netns-isolation-v1-1-ced02054ea61@redhat.com?part=1