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Tsirkin" Cc: Stefano Garzarella , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Stefan Hajnoczi , Jason Wang , Eugenio =?iso-8859-1?Q?P=E9rez?= , Xuan Zhuo , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Bryan Tan , Vishnu Dasa , Broadcom internal kernel review list , Shuah Khan , Long Li , linux-kernel@vger.kernel.org, virtualization@lists.linux.dev, netdev@vger.kernel.org, kvm@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-kselftest@vger.kernel.org, berrange@redhat.com, Sargun Dhillon , Bobby Eshleman Subject: Re: [PATCH RFC net-next v13 02/13] vsock: add netns to vsock core Message-ID: References: <20251223-vsock-vmtest-v13-0-9d6db8e7c80b@meta.com> <20251223-vsock-vmtest-v13-2-9d6db8e7c80b@meta.com> <20260111013536-mutt-send-email-mst@kernel.org> Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260111013536-mutt-send-email-mst@kernel.org> On Sun, Jan 11, 2026 at 01:43:37AM -0500, Michael S. Tsirkin wrote: > On Tue, Dec 23, 2025 at 04:28:36PM -0800, Bobby Eshleman wrote: > > From: Bobby Eshleman > > > > Add netns logic to vsock core. Additionally, modify transport hook > > prototypes to be used by later transport-specific patches (e.g., > > *_seqpacket_allow()). > > > > Namespaces are supported primarily by changing socket lookup functions > > (e.g., vsock_find_connected_socket()) to take into account the socket > > namespace and the namespace mode before considering a candidate socket a > > "match". > > > > This patch also introduces the sysctl /proc/sys/net/vsock/ns_mode to > > report the mode and /proc/sys/net/vsock/child_ns_mode to set the mode > > for new namespaces. > > > > Add netns functionality (initialization, passing to transports, procfs, > > etc...) to the af_vsock socket layer. Later patches that add netns > > support to transports depend on this patch. > > > > dgram_allow(), stream_allow(), and seqpacket_allow() callbacks are > > modified to take a vsk in order to perform logic on namespace modes. In > > future patches, the net will also be used for socket > > lookups in these functions. > > > > Signed-off-by: Bobby Eshleman > > ... > > > > static int __vsock_bind_connectible(struct vsock_sock *vsk, > > struct sockaddr_vm *addr) > > { > > + struct net *net = sock_net(sk_vsock(vsk)); > > static u32 port; > > struct sockaddr_vm new_addr; > > > > > Hmm this static port gives me pause. So some port number info leaks > between namespaces. I am not saying it's a big security issue > and yet ... people expect isolation. Probably the easiest solution is making it per-ns, my quick rough draft looks like this: diff --git a/include/net/netns/vsock.h b/include/net/netns/vsock.h index e2325e2d6ec5..b34d69a22fa8 100644 --- a/include/net/netns/vsock.h +++ b/include/net/netns/vsock.h @@ -11,6 +11,10 @@ enum vsock_net_mode { struct netns_vsock { struct ctl_table_header *sysctl_hdr; + + /* protected by the vsock_table_lock in af_vsock.c */ + u32 port; + enum vsock_net_mode mode; enum vsock_net_mode child_ns_mode; }; diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index 9d614e4a4fa5..cd2a47140134 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -748,11 +748,10 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk, struct sockaddr_vm *addr) { struct net *net = sock_net(sk_vsock(vsk)); - static u32 port; struct sockaddr_vm new_addr; - if (!port) - port = get_random_u32_above(LAST_RESERVED_PORT); + if (!net->vsock.port) + net->vsock.port = get_random_u32_above(LAST_RESERVED_PORT); vsock_addr_init(&new_addr, addr->svm_cid, addr->svm_port); @@ -761,11 +760,11 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk, unsigned int i; for (i = 0; i < MAX_PORT_RETRIES; i++) { - if (port == VMADDR_PORT_ANY || - port <= LAST_RESERVED_PORT) - port = LAST_RESERVED_PORT + 1; + if (net->vsock.port == VMADDR_PORT_ANY || + net->vsock.port <= LAST_RESERVED_PORT) + net->vsock.port = LAST_RESERVED_PORT + 1; - new_addr.svm_port = port++; + new_addr.svm_port = net->vsock.port++; if (!__vsock_find_bound_socket_net(&new_addr, net)) { found = true; Not as nice, but not necessarily horrid. WDYT? Best, Bobby