On Mon, Jan 12, 2026 at 03:34:31PM -0800, Bobby Eshleman wrote: > 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 <[email protected]> > > > > > > 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 <[email protected]> > > > > ... > > > > > > > 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; > > >
Another option being to follow inet's path and use siphash_4u32() the way that secure_ipv4_port_ephemeral() does...
