From: Bobby Eshleman <bobbyeshleman@meta.com>
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 <bobbyeshleman@meta.com>
---
Changes in v15:
- make static port in __vsock_bind_connectible per-netns
- remove __net_initdata because we want the ops beyond just boot
- add vsock_init_ns_mode kernel cmdline parameter to set init ns mode
- use if (ret || !write) in __vsock_net_mode_string() (Stefano)
- add vsock_net_mode_global() (Stefano)
- hide !net == VSOCK_NET_MODE_GLOBAL inside vsock_net_mode() (Stefano)
- clarify af_vsock.c comments on ns_mode/child_ns_mode (Stefano)
Changes in v14:
- include linux/sysctl.h in af_vsock.c
- squash patch 'vsock: add per-net vsock NS mode state' into this patch
(prior version can be found here):
https://lore.kernel.org/all/20251223-vsock-vmtest-v13-1-9d6db8e7c80b@meta.com/)
Changes in v13:
- remove net_mode and replace with direct accesses to net->vsock.mode,
since this is now immutable.
- update comments about mode behavior and mutability, and sysctl API
- only pass NULL for net when wanting global, instead of net_mode ==
VSOCK_NET_MODE_GLOBAL. This reflects the new logic
of vsock_net_check_mode() that only requires net pointers (not
net_mode).
- refactor sysctl string code into a re-usable function, because
child_ns_mode and ns_mode both handle the same strings.
- remove redundant vsock_net_init(&init_net) call in module init because
pernet registration calls the callback on the init_net too
Changes in v12:
- return true in dgram_allow(), stream_allow(), and seqpacket_allow()
only if net_mode == VSOCK_NET_MODE_GLOBAL (Stefano)
- document bind(VMADDR_CID_ANY) case in af_vsock.c (Stefano)
- change order of stream_allow() call in vmci so we can pass vsk
to it
Changes in v10:
- add file-level comment about what happens to sockets/devices
when the namespace mode changes (Stefano)
- change the 'if (write)' boolean in vsock_net_mode_string() to
if (!write), this simplifies a later patch which adds "goto"
for mutex unlocking on function exit.
Changes in v9:
- remove virtio_vsock_alloc_rx_skb() (Stefano)
- remove vsock_global_dummy_net, not needed as net=NULL +
net_mode=VSOCK_NET_MODE_GLOBAL achieves identical result
Changes in v7:
- hv_sock: fix hyperv build error
- explain why vhost does not use the dummy
- explain usage of __vsock_global_dummy_net
- explain why VSOCK_NET_MODE_STR_MAX is 8 characters
- use switch-case in vsock_net_mode_string()
- avoid changing transports as much as possible
- add vsock_find_{bound,connected}_socket_net()
- rename `vsock_hdr` to `sysctl_hdr`
- add virtio_vsock_alloc_linear_skb() wrapper for setting dummy net and
global mode for virtio-vsock, move skb->cb zero-ing into wrapper
- explain seqpacket_allow() change
- move net setting to __vsock_create() instead of vsock_create() so
that child sockets also have their net assigned upon accept()
Changes in v6:
- unregister sysctl ops in vsock_exit()
- af_vsock: clarify description of CID behavior
- af_vsock: fix buf vs buffer naming, and length checking
- af_vsock: fix length checking w/ correct ctl_table->maxlen
Changes in v5:
- vsock_global_net() -> vsock_global_dummy_net()
- update comments for new uAPI
- use /proc/sys/net/vsock/ns_mode instead of /proc/net/vsock_ns_mode
- add prototype changes so patch remains compilable
---
Documentation/admin-guide/kernel-parameters.txt | 14 +
MAINTAINERS | 1 +
drivers/vhost/vsock.c | 6 +-
include/linux/virtio_vsock.h | 4 +-
include/net/af_vsock.h | 61 ++++-
include/net/net_namespace.h | 4 +
include/net/netns/vsock.h | 21 ++
net/vmw_vsock/af_vsock.c | 328 ++++++++++++++++++++++--
net/vmw_vsock/hyperv_transport.c | 7 +-
net/vmw_vsock/virtio_transport.c | 9 +-
net/vmw_vsock/virtio_transport_common.c | 6 +-
net/vmw_vsock/vmci_transport.c | 26 +-
net/vmw_vsock/vsock_loopback.c | 8 +-
13 files changed, 444 insertions(+), 51 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a8d0afde7f85..b6e3bfe365a1 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -8253,6 +8253,20 @@ Kernel parameters
them quite hard to use for exploits but
might break your system.
+ vsock_init_ns_mode=
+ [KNL,NET] Set the vsock namespace mode for the init
+ (root) network namespace.
+
+ global [default] The init namespace operates in
+ global mode where CIDs are system-wide and
+ sockets can communicate across global
+ namespaces.
+
+ local The init namespace operates in local mode
+ where CIDs are private to the namespace and
+ sockets can only communicate within the same
+ namespace.
+
vt.color= [VT] Default text color.
Format: 0xYX, X = foreground, Y = background.
Default: 0x07 = light gray on black.
diff --git a/MAINTAINERS b/MAINTAINERS
index afc71089ba09..c48a2e047686 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -27557,6 +27557,7 @@ L: netdev@vger.kernel.org
S: Maintained
F: drivers/vhost/vsock.c
F: include/linux/virtio_vsock.h
+F: include/net/netns/vsock.h
F: include/uapi/linux/virtio_vsock.h
F: net/vmw_vsock/virtio_transport.c
F: net/vmw_vsock/virtio_transport_common.c
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 552cfb53498a..647ded6f6ea5 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -407,7 +407,8 @@ static bool vhost_transport_msgzerocopy_allow(void)
return true;
}
-static bool vhost_transport_seqpacket_allow(u32 remote_cid);
+static bool vhost_transport_seqpacket_allow(struct vsock_sock *vsk,
+ u32 remote_cid);
static struct virtio_transport vhost_transport = {
.transport = {
@@ -463,7 +464,8 @@ static struct virtio_transport vhost_transport = {
.send_pkt = vhost_transport_send_pkt,
};
-static bool vhost_transport_seqpacket_allow(u32 remote_cid)
+static bool vhost_transport_seqpacket_allow(struct vsock_sock *vsk,
+ u32 remote_cid)
{
struct vhost_vsock *vsock;
bool seqpacket_allow = false;
diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index 0c67543a45c8..1845e8d4f78d 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -256,10 +256,10 @@ void virtio_transport_notify_buffer_size(struct vsock_sock *vsk, u64 *val);
u64 virtio_transport_stream_rcvhiwat(struct vsock_sock *vsk);
bool virtio_transport_stream_is_active(struct vsock_sock *vsk);
-bool virtio_transport_stream_allow(u32 cid, u32 port);
+bool virtio_transport_stream_allow(struct vsock_sock *vsk, u32 cid, u32 port);
int virtio_transport_dgram_bind(struct vsock_sock *vsk,
struct sockaddr_vm *addr);
-bool virtio_transport_dgram_allow(u32 cid, u32 port);
+bool virtio_transport_dgram_allow(struct vsock_sock *vsk, u32 cid, u32 port);
int virtio_transport_connect(struct vsock_sock *vsk);
diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index d40e978126e3..d3ff48a2fbe0 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -10,6 +10,7 @@
#include <linux/kernel.h>
#include <linux/workqueue.h>
+#include <net/netns/vsock.h>
#include <net/sock.h>
#include <uapi/linux/vm_sockets.h>
@@ -124,7 +125,7 @@ struct vsock_transport {
size_t len, int flags);
int (*dgram_enqueue)(struct vsock_sock *, struct sockaddr_vm *,
struct msghdr *, size_t len);
- bool (*dgram_allow)(u32 cid, u32 port);
+ bool (*dgram_allow)(struct vsock_sock *vsk, u32 cid, u32 port);
/* STREAM. */
/* TODO: stream_bind() */
@@ -136,14 +137,14 @@ struct vsock_transport {
s64 (*stream_has_space)(struct vsock_sock *);
u64 (*stream_rcvhiwat)(struct vsock_sock *);
bool (*stream_is_active)(struct vsock_sock *);
- bool (*stream_allow)(u32 cid, u32 port);
+ bool (*stream_allow)(struct vsock_sock *vsk, u32 cid, u32 port);
/* SEQ_PACKET. */
ssize_t (*seqpacket_dequeue)(struct vsock_sock *vsk, struct msghdr *msg,
int flags);
int (*seqpacket_enqueue)(struct vsock_sock *vsk, struct msghdr *msg,
size_t len);
- bool (*seqpacket_allow)(u32 remote_cid);
+ bool (*seqpacket_allow)(struct vsock_sock *vsk, u32 remote_cid);
u32 (*seqpacket_has_data)(struct vsock_sock *vsk);
/* Notification. */
@@ -216,6 +217,11 @@ void vsock_remove_connected(struct vsock_sock *vsk);
struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr);
struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
struct sockaddr_vm *dst);
+struct sock *vsock_find_bound_socket_net(struct sockaddr_vm *addr,
+ struct net *net);
+struct sock *vsock_find_connected_socket_net(struct sockaddr_vm *src,
+ struct sockaddr_vm *dst,
+ struct net *net);
void vsock_remove_sock(struct vsock_sock *vsk);
void vsock_for_each_connected_socket(struct vsock_transport *transport,
void (*fn)(struct sock *sk));
@@ -256,4 +262,53 @@ static inline bool vsock_msgzerocopy_allow(const struct vsock_transport *t)
{
return t->msgzerocopy_allow && t->msgzerocopy_allow();
}
+
+static inline enum vsock_net_mode vsock_net_mode(struct net *net)
+{
+ if (!net)
+ return VSOCK_NET_MODE_GLOBAL;
+
+ return READ_ONCE(net->vsock.mode);
+}
+
+static inline bool vsock_net_mode_global(struct vsock_sock *vsk)
+{
+ return vsock_net_mode(sock_net(sk_vsock(vsk))) == VSOCK_NET_MODE_GLOBAL;
+}
+
+static inline void vsock_net_set_child_mode(struct net *net,
+ enum vsock_net_mode mode)
+{
+ WRITE_ONCE(net->vsock.child_ns_mode, mode);
+}
+
+static inline enum vsock_net_mode vsock_net_child_mode(struct net *net)
+{
+ return READ_ONCE(net->vsock.child_ns_mode);
+}
+
+/* Return true if two namespaces pass the mode rules. Otherwise, return false.
+ *
+ * A NULL namespace is treated as VSOCK_NET_MODE_GLOBAL.
+ *
+ * Read more about modes in the comment header of net/vmw_vsock/af_vsock.c.
+ */
+static inline bool vsock_net_check_mode(struct net *ns0, struct net *ns1)
+{
+ enum vsock_net_mode mode0, mode1;
+
+ /* Any vsocks within the same network namespace are always reachable,
+ * regardless of the mode.
+ */
+ if (net_eq(ns0, ns1))
+ return true;
+
+ mode0 = vsock_net_mode(ns0);
+ mode1 = vsock_net_mode(ns1);
+
+ /* Different namespaces are only reachable if they are both
+ * global mode.
+ */
+ return mode0 == VSOCK_NET_MODE_GLOBAL && mode0 == mode1;
+}
#endif /* __AF_VSOCK_H__ */
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index cb664f6e3558..66d3de1d935f 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -37,6 +37,7 @@
#include <net/netns/smc.h>
#include <net/netns/bpf.h>
#include <net/netns/mctp.h>
+#include <net/netns/vsock.h>
#include <net/net_trackers.h>
#include <linux/ns_common.h>
#include <linux/idr.h>
@@ -196,6 +197,9 @@ struct net {
/* Move to a better place when the config guard is removed. */
struct mutex rtnl_mutex;
#endif
+#if IS_ENABLED(CONFIG_VSOCKETS)
+ struct netns_vsock vsock;
+#endif
} __randomize_layout;
#include <linux/seq_file_net.h>
diff --git a/include/net/netns/vsock.h b/include/net/netns/vsock.h
new file mode 100644
index 000000000000..b34d69a22fa8
--- /dev/null
+++ b/include/net/netns/vsock.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __NET_NET_NAMESPACE_VSOCK_H
+#define __NET_NET_NAMESPACE_VSOCK_H
+
+#include <linux/types.h>
+
+enum vsock_net_mode {
+ VSOCK_NET_MODE_GLOBAL,
+ VSOCK_NET_MODE_LOCAL,
+};
+
+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;
+};
+#endif /* __NET_NET_NAMESPACE_VSOCK_H */
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index a3505a4dcee0..3fc8160d51df 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -83,6 +83,48 @@
* TCP_ESTABLISHED - connected
* TCP_CLOSING - disconnecting
* TCP_LISTEN - listening
+ *
+ * - Namespaces in vsock support two different modes: "local" and "global".
+ * Each mode defines how the namespace interacts with CIDs.
+ * Each namespace exposes two sysctl files:
+ *
+ * - /proc/sys/net/vsock/ns_mode (read-only) reports the current namespace's
+ * mode, which is set at namespace creation and immutable thereafter.
+ * - /proc/sys/net/vsock/child_ns_mode (writable) controls what mode future
+ * child namespaces will inherit when created. The default is "global".
+ *
+ * Changing child_ns_mode only affects newly created namespaces, not the
+ * current namespace or existing children. At namespace creation, ns_mode
+ * is inherited from the parent's child_ns_mode.
+ *
+ * The modes affect the allocation and accessibility of CIDs as follows:
+ *
+ * - global - access and allocation are all system-wide
+ * - all CID allocation from global namespaces draw from the same
+ * system-wide pool.
+ * - if one global namespace has already allocated some CID, another
+ * global namespace will not be able to allocate the same CID.
+ * - global mode AF_VSOCK sockets can reach any VM or socket in any global
+ * namespace, they are not contained to only their own namespace.
+ * - AF_VSOCK sockets in a global mode namespace cannot reach VMs or
+ * sockets in any local mode namespace.
+ * - local - access and allocation are contained within the namespace
+ * - CID allocation draws only from a private pool local only to the
+ * namespace, and does not affect the CIDs available for allocation in any
+ * other namespace (global or local).
+ * - VMs in a local namespace do not collide with CIDs in any other local
+ * namespace or any global namespace. For example, if a VM in a local mode
+ * namespace is given CID 10, then CID 10 is still available for
+ * allocation in any other namespace, but not in the same namespace.
+ * - AF_VSOCK sockets in a local mode namespace can connect only to VMs or
+ * other sockets within their own namespace.
+ * - sockets bound to VMADDR_CID_ANY in local namespaces will never resolve
+ * to any transport that is not compatible with local mode. There is no
+ * error that propagates to the user (as there is for connection attempts)
+ * because it is possible for some packet to reach this socket from
+ * a different transport that *does* support local mode. For
+ * example, virtio-vsock may not support local mode, but the socket
+ * may still accept a connection from vhost-vsock which does.
*/
#include <linux/compat.h>
@@ -100,20 +142,31 @@
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/net.h>
+#include <linux/proc_fs.h>
#include <linux/poll.h>
#include <linux/random.h>
#include <linux/skbuff.h>
#include <linux/smp.h>
#include <linux/socket.h>
#include <linux/stddef.h>
+#include <linux/sysctl.h>
#include <linux/unistd.h>
#include <linux/wait.h>
#include <linux/workqueue.h>
#include <net/sock.h>
#include <net/af_vsock.h>
+#include <net/netns/vsock.h>
#include <uapi/linux/vm_sockets.h>
#include <uapi/asm-generic/ioctls.h>
+#define VSOCK_NET_MODE_STR_GLOBAL "global"
+#define VSOCK_NET_MODE_STR_LOCAL "local"
+
+/* 6 chars for "global", 1 for null-terminator, and 1 more for '\n'.
+ * The newline is added by proc_dostring() for read operations.
+ */
+#define VSOCK_NET_MODE_STR_MAX 8
+
static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr);
static void vsock_sk_destruct(struct sock *sk);
static int vsock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
@@ -149,6 +202,21 @@ static const struct vsock_transport *transport_dgram;
static const struct vsock_transport *transport_local;
static DEFINE_MUTEX(vsock_register_mutex);
+static enum vsock_net_mode vsock_init_ns_mode = VSOCK_NET_MODE_GLOBAL;
+
+#ifndef MODULE
+static int __init vsock_init_ns_mode_setup(char *str)
+{
+ if (!strcmp(str, VSOCK_NET_MODE_STR_LOCAL))
+ vsock_init_ns_mode = VSOCK_NET_MODE_LOCAL;
+ else if (!strcmp(str, VSOCK_NET_MODE_STR_GLOBAL))
+ vsock_init_ns_mode = VSOCK_NET_MODE_GLOBAL;
+
+ return 1;
+}
+__setup("vsock_init_ns_mode=", vsock_init_ns_mode_setup);
+#endif
+
/**** UTILS ****/
/* Each bound VSocket is stored in the bind hash table and each connected
@@ -235,33 +303,42 @@ static void __vsock_remove_connected(struct vsock_sock *vsk)
sock_put(&vsk->sk);
}
-static struct sock *__vsock_find_bound_socket(struct sockaddr_vm *addr)
+static struct sock *__vsock_find_bound_socket_net(struct sockaddr_vm *addr,
+ struct net *net)
{
struct vsock_sock *vsk;
list_for_each_entry(vsk, vsock_bound_sockets(addr), bound_table) {
- if (vsock_addr_equals_addr(addr, &vsk->local_addr))
- return sk_vsock(vsk);
+ struct sock *sk = sk_vsock(vsk);
+
+ if (vsock_addr_equals_addr(addr, &vsk->local_addr) &&
+ vsock_net_check_mode(sock_net(sk), net))
+ return sk;
if (addr->svm_port == vsk->local_addr.svm_port &&
(vsk->local_addr.svm_cid == VMADDR_CID_ANY ||
- addr->svm_cid == VMADDR_CID_ANY))
- return sk_vsock(vsk);
+ addr->svm_cid == VMADDR_CID_ANY) &&
+ vsock_net_check_mode(sock_net(sk), net))
+ return sk;
}
return NULL;
}
-static struct sock *__vsock_find_connected_socket(struct sockaddr_vm *src,
- struct sockaddr_vm *dst)
+static struct sock *
+__vsock_find_connected_socket_net(struct sockaddr_vm *src,
+ struct sockaddr_vm *dst, struct net *net)
{
struct vsock_sock *vsk;
list_for_each_entry(vsk, vsock_connected_sockets(src, dst),
connected_table) {
+ struct sock *sk = sk_vsock(vsk);
+
if (vsock_addr_equals_addr(src, &vsk->remote_addr) &&
- dst->svm_port == vsk->local_addr.svm_port) {
- return sk_vsock(vsk);
+ dst->svm_port == vsk->local_addr.svm_port &&
+ vsock_net_check_mode(sock_net(sk), net)) {
+ return sk;
}
}
@@ -304,12 +381,13 @@ void vsock_remove_connected(struct vsock_sock *vsk)
}
EXPORT_SYMBOL_GPL(vsock_remove_connected);
-struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr)
+struct sock *vsock_find_bound_socket_net(struct sockaddr_vm *addr,
+ struct net *net)
{
struct sock *sk;
spin_lock_bh(&vsock_table_lock);
- sk = __vsock_find_bound_socket(addr);
+ sk = __vsock_find_bound_socket_net(addr, net);
if (sk)
sock_hold(sk);
@@ -317,15 +395,22 @@ struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr)
return sk;
}
+EXPORT_SYMBOL_GPL(vsock_find_bound_socket_net);
+
+struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr)
+{
+ return vsock_find_bound_socket_net(addr, NULL);
+}
EXPORT_SYMBOL_GPL(vsock_find_bound_socket);
-struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
- struct sockaddr_vm *dst)
+struct sock *vsock_find_connected_socket_net(struct sockaddr_vm *src,
+ struct sockaddr_vm *dst,
+ struct net *net)
{
struct sock *sk;
spin_lock_bh(&vsock_table_lock);
- sk = __vsock_find_connected_socket(src, dst);
+ sk = __vsock_find_connected_socket_net(src, dst, net);
if (sk)
sock_hold(sk);
@@ -333,6 +418,13 @@ struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
return sk;
}
+EXPORT_SYMBOL_GPL(vsock_find_connected_socket_net);
+
+struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
+ struct sockaddr_vm *dst)
+{
+ return vsock_find_connected_socket_net(src, dst, NULL);
+}
EXPORT_SYMBOL_GPL(vsock_find_connected_socket);
void vsock_remove_sock(struct vsock_sock *vsk)
@@ -528,7 +620,7 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)
if (sk->sk_type == SOCK_SEQPACKET) {
if (!new_transport->seqpacket_allow ||
- !new_transport->seqpacket_allow(remote_cid)) {
+ !new_transport->seqpacket_allow(vsk, remote_cid)) {
module_put(new_transport->module);
return -ESOCKTNOSUPPORT;
}
@@ -676,11 +768,11 @@ static void vsock_pending_work(struct work_struct *work)
static int __vsock_bind_connectible(struct vsock_sock *vsk,
struct sockaddr_vm *addr)
{
- static u32 port;
+ struct net *net = sock_net(sk_vsock(vsk));
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);
@@ -689,13 +781,13 @@ 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(&new_addr)) {
+ if (!__vsock_find_bound_socket_net(&new_addr, net)) {
found = true;
break;
}
@@ -712,7 +804,7 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
return -EACCES;
}
- if (__vsock_find_bound_socket(&new_addr))
+ if (__vsock_find_bound_socket_net(&new_addr, net))
return -EADDRINUSE;
}
@@ -1314,7 +1406,7 @@ static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
goto out;
}
- if (!transport->dgram_allow(remote_addr->svm_cid,
+ if (!transport->dgram_allow(vsk, remote_addr->svm_cid,
remote_addr->svm_port)) {
err = -EINVAL;
goto out;
@@ -1355,7 +1447,7 @@ static int vsock_dgram_connect(struct socket *sock,
if (err)
goto out;
- if (!vsk->transport->dgram_allow(remote_addr->svm_cid,
+ if (!vsk->transport->dgram_allow(vsk, remote_addr->svm_cid,
remote_addr->svm_port)) {
err = -EINVAL;
goto out;
@@ -1585,7 +1677,7 @@ static int vsock_connect(struct socket *sock, struct sockaddr_unsized *addr,
* endpoints.
*/
if (!transport ||
- !transport->stream_allow(remote_addr->svm_cid,
+ !transport->stream_allow(vsk, remote_addr->svm_cid,
remote_addr->svm_port)) {
err = -ENETUNREACH;
goto out;
@@ -2662,6 +2754,180 @@ static struct miscdevice vsock_device = {
.fops = &vsock_device_ops,
};
+static int __vsock_net_mode_string(const struct ctl_table *table, int write,
+ void *buffer, size_t *lenp, loff_t *ppos,
+ enum vsock_net_mode mode,
+ enum vsock_net_mode *new_mode)
+{
+ char data[VSOCK_NET_MODE_STR_MAX] = {0};
+ struct ctl_table tmp;
+ int ret;
+
+ if (!table->data || !table->maxlen || !*lenp) {
+ *lenp = 0;
+ return 0;
+ }
+
+ tmp = *table;
+ tmp.data = data;
+
+ if (!write) {
+ const char *p;
+
+ switch (mode) {
+ case VSOCK_NET_MODE_GLOBAL:
+ p = VSOCK_NET_MODE_STR_GLOBAL;
+ break;
+ case VSOCK_NET_MODE_LOCAL:
+ p = VSOCK_NET_MODE_STR_LOCAL;
+ break;
+ default:
+ WARN_ONCE(true, "netns has invalid vsock mode");
+ *lenp = 0;
+ return 0;
+ }
+
+ strscpy(data, p, sizeof(data));
+ tmp.maxlen = strlen(p);
+ }
+
+ ret = proc_dostring(&tmp, write, buffer, lenp, ppos);
+ if (ret || !write)
+ return ret;
+
+ if (*lenp >= sizeof(data))
+ return -EINVAL;
+
+ if (!strncmp(data, VSOCK_NET_MODE_STR_GLOBAL, sizeof(data)))
+ *new_mode = VSOCK_NET_MODE_GLOBAL;
+ else if (!strncmp(data, VSOCK_NET_MODE_STR_LOCAL, sizeof(data)))
+ *new_mode = VSOCK_NET_MODE_LOCAL;
+ else
+ return -EINVAL;
+
+ return 0;
+}
+
+static int vsock_net_mode_string(const struct ctl_table *table, int write,
+ void *buffer, size_t *lenp, loff_t *ppos)
+{
+ struct net *net;
+
+ if (write)
+ return -EPERM;
+
+ net = current->nsproxy->net_ns;
+
+ return __vsock_net_mode_string(table, write, buffer, lenp, ppos,
+ vsock_net_mode(net), NULL);
+}
+
+static int vsock_net_child_mode_string(const struct ctl_table *table, int write,
+ void *buffer, size_t *lenp, loff_t *ppos)
+{
+ enum vsock_net_mode new_mode;
+ struct net *net;
+ int ret;
+
+ net = current->nsproxy->net_ns;
+
+ ret = __vsock_net_mode_string(table, write, buffer, lenp, ppos,
+ vsock_net_child_mode(net), &new_mode);
+ if (ret)
+ return ret;
+
+ if (write)
+ vsock_net_set_child_mode(net, new_mode);
+
+ return 0;
+}
+
+static struct ctl_table vsock_table[] = {
+ {
+ .procname = "ns_mode",
+ .data = &init_net.vsock.mode,
+ .maxlen = VSOCK_NET_MODE_STR_MAX,
+ .mode = 0444,
+ .proc_handler = vsock_net_mode_string
+ },
+ {
+ .procname = "child_ns_mode",
+ .data = &init_net.vsock.child_ns_mode,
+ .maxlen = VSOCK_NET_MODE_STR_MAX,
+ .mode = 0644,
+ .proc_handler = vsock_net_child_mode_string
+ },
+};
+
+static int __net_init vsock_sysctl_register(struct net *net)
+{
+ struct ctl_table *table;
+
+ if (net_eq(net, &init_net)) {
+ table = vsock_table;
+ } else {
+ table = kmemdup(vsock_table, sizeof(vsock_table), GFP_KERNEL);
+ if (!table)
+ goto err_alloc;
+
+ table[0].data = &net->vsock.mode;
+ table[1].data = &net->vsock.child_ns_mode;
+ }
+
+ net->vsock.sysctl_hdr = register_net_sysctl_sz(net, "net/vsock", table,
+ ARRAY_SIZE(vsock_table));
+ if (!net->vsock.sysctl_hdr)
+ goto err_reg;
+
+ return 0;
+
+err_reg:
+ if (!net_eq(net, &init_net))
+ kfree(table);
+err_alloc:
+ return -ENOMEM;
+}
+
+static void vsock_sysctl_unregister(struct net *net)
+{
+ const struct ctl_table *table;
+
+ table = net->vsock.sysctl_hdr->ctl_table_arg;
+ unregister_net_sysctl_table(net->vsock.sysctl_hdr);
+ if (!net_eq(net, &init_net))
+ kfree(table);
+}
+
+static void vsock_net_init(struct net *net)
+{
+ if (net_eq(net, &init_net))
+ net->vsock.mode = vsock_init_ns_mode;
+ else
+ net->vsock.mode = vsock_net_child_mode(current->nsproxy->net_ns);
+
+ net->vsock.child_ns_mode = VSOCK_NET_MODE_GLOBAL;
+}
+
+static __net_init int vsock_sysctl_init_net(struct net *net)
+{
+ vsock_net_init(net);
+
+ if (vsock_sysctl_register(net))
+ return -ENOMEM;
+
+ return 0;
+}
+
+static __net_exit void vsock_sysctl_exit_net(struct net *net)
+{
+ vsock_sysctl_unregister(net);
+}
+
+static struct pernet_operations vsock_sysctl_ops = {
+ .init = vsock_sysctl_init_net,
+ .exit = vsock_sysctl_exit_net,
+};
+
static int __init vsock_init(void)
{
int err = 0;
@@ -2689,10 +2955,17 @@ static int __init vsock_init(void)
goto err_unregister_proto;
}
+ if (register_pernet_subsys(&vsock_sysctl_ops)) {
+ err = -ENOMEM;
+ goto err_unregister_sock;
+ }
+
vsock_bpf_build_proto();
return 0;
+err_unregister_sock:
+ sock_unregister(AF_VSOCK);
err_unregister_proto:
proto_unregister(&vsock_proto);
err_deregister_misc:
@@ -2706,6 +2979,7 @@ static void __exit vsock_exit(void)
misc_deregister(&vsock_device);
sock_unregister(AF_VSOCK);
proto_unregister(&vsock_proto);
+ unregister_pernet_subsys(&vsock_sysctl_ops);
}
const struct vsock_transport *vsock_core_get_transport(struct vsock_sock *vsk)
diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
index 432fcbbd14d4..c3010c874308 100644
--- a/net/vmw_vsock/hyperv_transport.c
+++ b/net/vmw_vsock/hyperv_transport.c
@@ -570,7 +570,7 @@ static int hvs_dgram_enqueue(struct vsock_sock *vsk,
return -EOPNOTSUPP;
}
-static bool hvs_dgram_allow(u32 cid, u32 port)
+static bool hvs_dgram_allow(struct vsock_sock *vsk, u32 cid, u32 port)
{
return false;
}
@@ -745,8 +745,11 @@ static bool hvs_stream_is_active(struct vsock_sock *vsk)
return hvs->chan != NULL;
}
-static bool hvs_stream_allow(u32 cid, u32 port)
+static bool hvs_stream_allow(struct vsock_sock *vsk, u32 cid, u32 port)
{
+ if (!vsock_net_mode_global(vsk))
+ return false;
+
if (cid == VMADDR_CID_HOST)
return true;
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 8c867023a2e5..f0a9e51118f3 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -536,7 +536,8 @@ static bool virtio_transport_msgzerocopy_allow(void)
return true;
}
-static bool virtio_transport_seqpacket_allow(u32 remote_cid);
+static bool virtio_transport_seqpacket_allow(struct vsock_sock *vsk,
+ u32 remote_cid);
static struct virtio_transport virtio_transport = {
.transport = {
@@ -593,11 +594,15 @@ static struct virtio_transport virtio_transport = {
.can_msgzerocopy = virtio_transport_can_msgzerocopy,
};
-static bool virtio_transport_seqpacket_allow(u32 remote_cid)
+static bool
+virtio_transport_seqpacket_allow(struct vsock_sock *vsk, u32 remote_cid)
{
struct virtio_vsock *vsock;
bool seqpacket_allow;
+ if (!vsock_net_mode_global(vsk))
+ return false;
+
seqpacket_allow = false;
rcu_read_lock();
vsock = rcu_dereference(the_virtio_vsock);
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index dcc8a1d5851e..fdb8f5b3fa60 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -1043,9 +1043,9 @@ bool virtio_transport_stream_is_active(struct vsock_sock *vsk)
}
EXPORT_SYMBOL_GPL(virtio_transport_stream_is_active);
-bool virtio_transport_stream_allow(u32 cid, u32 port)
+bool virtio_transport_stream_allow(struct vsock_sock *vsk, u32 cid, u32 port)
{
- return true;
+ return vsock_net_mode(sock_net(sk_vsock(vsk))) == VSOCK_NET_MODE_GLOBAL;
}
EXPORT_SYMBOL_GPL(virtio_transport_stream_allow);
@@ -1056,7 +1056,7 @@ int virtio_transport_dgram_bind(struct vsock_sock *vsk,
}
EXPORT_SYMBOL_GPL(virtio_transport_dgram_bind);
-bool virtio_transport_dgram_allow(u32 cid, u32 port)
+bool virtio_transport_dgram_allow(struct vsock_sock *vsk, u32 cid, u32 port)
{
return false;
}
diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
index 7eccd6708d66..00f6bbdb035a 100644
--- a/net/vmw_vsock/vmci_transport.c
+++ b/net/vmw_vsock/vmci_transport.c
@@ -646,13 +646,17 @@ static int vmci_transport_recv_dgram_cb(void *data, struct vmci_datagram *dg)
return VMCI_SUCCESS;
}
-static bool vmci_transport_stream_allow(u32 cid, u32 port)
+static bool vmci_transport_stream_allow(struct vsock_sock *vsk, u32 cid,
+ u32 port)
{
static const u32 non_socket_contexts[] = {
VMADDR_CID_LOCAL,
};
int i;
+ if (!vsock_net_mode_global(vsk))
+ return false;
+
BUILD_BUG_ON(sizeof(cid) != sizeof(*non_socket_contexts));
for (i = 0; i < ARRAY_SIZE(non_socket_contexts); i++) {
@@ -682,12 +686,10 @@ static int vmci_transport_recv_stream_cb(void *data, struct vmci_datagram *dg)
err = VMCI_SUCCESS;
bh_process_pkt = false;
- /* Ignore incoming packets from contexts without sockets, or resources
- * that aren't vsock implementations.
+ /* Ignore incoming packets from resources that aren't vsock
+ * implementations.
*/
-
- if (!vmci_transport_stream_allow(dg->src.context, -1)
- || vmci_transport_peer_rid(dg->src.context) != dg->src.resource)
+ if (vmci_transport_peer_rid(dg->src.context) != dg->src.resource)
return VMCI_ERROR_NO_ACCESS;
if (VMCI_DG_SIZE(dg) < sizeof(*pkt))
@@ -749,6 +751,12 @@ static int vmci_transport_recv_stream_cb(void *data, struct vmci_datagram *dg)
goto out;
}
+ /* Ignore incoming packets from contexts without sockets. */
+ if (!vmci_transport_stream_allow(vsk, dg->src.context, -1)) {
+ err = VMCI_ERROR_NO_ACCESS;
+ goto out;
+ }
+
/* We do most everything in a work queue, but let's fast path the
* notification of reads and writes to help data transfer performance.
* We can only do this if there is no process context code executing
@@ -1784,8 +1792,12 @@ static int vmci_transport_dgram_dequeue(struct vsock_sock *vsk,
return err;
}
-static bool vmci_transport_dgram_allow(u32 cid, u32 port)
+static bool vmci_transport_dgram_allow(struct vsock_sock *vsk, u32 cid,
+ u32 port)
{
+ if (!vsock_net_mode_global(vsk))
+ return false;
+
if (cid == VMADDR_CID_HYPERVISOR) {
/* Registrations of PBRPC Servers do not modify VMX/Hypervisor
* state and are allowed.
diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c
index bc2ff918b315..deff68c64a09 100644
--- a/net/vmw_vsock/vsock_loopback.c
+++ b/net/vmw_vsock/vsock_loopback.c
@@ -46,7 +46,8 @@ static int vsock_loopback_cancel_pkt(struct vsock_sock *vsk)
return 0;
}
-static bool vsock_loopback_seqpacket_allow(u32 remote_cid);
+static bool vsock_loopback_seqpacket_allow(struct vsock_sock *vsk,
+ u32 remote_cid);
static bool vsock_loopback_msgzerocopy_allow(void)
{
return true;
@@ -106,9 +107,10 @@ static struct virtio_transport loopback_transport = {
.send_pkt = vsock_loopback_send_pkt,
};
-static bool vsock_loopback_seqpacket_allow(u32 remote_cid)
+static bool
+vsock_loopback_seqpacket_allow(struct vsock_sock *vsk, u32 remote_cid)
{
- return true;
+ return vsock_net_mode_global(vsk);
}
static void vsock_loopback_work(struct work_struct *work)
--
2.47.3On Fri, Jan 16, 2026 at 01:28:41PM -0800, Bobby Eshleman wrote:
>From: Bobby Eshleman <bobbyeshleman@meta.com>
>
>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.
nit: maybe we should mention here why we changed the random port
allocation
(not a big deal, only if you need to resend)
>
>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 <bobbyeshleman@meta.com>
>---
>Changes in v15:
>- make static port in __vsock_bind_connectible per-netns
>- remove __net_initdata because we want the ops beyond just boot
>- add vsock_init_ns_mode kernel cmdline parameter to set init ns mode
>- use if (ret || !write) in __vsock_net_mode_string() (Stefano)
>- add vsock_net_mode_global() (Stefano)
>- hide !net == VSOCK_NET_MODE_GLOBAL inside vsock_net_mode() (Stefano)
>- clarify af_vsock.c comments on ns_mode/child_ns_mode (Stefano)
>
>Changes in v14:
>- include linux/sysctl.h in af_vsock.c
>- squash patch 'vsock: add per-net vsock NS mode state' into this patch
> (prior version can be found here):
> https://lore.kernel.org/all/20251223-vsock-vmtest-v13-1-9d6db8e7c80b@meta.com/)
>
>Changes in v13:
>- remove net_mode and replace with direct accesses to net->vsock.mode,
> since this is now immutable.
>- update comments about mode behavior and mutability, and sysctl API
>- only pass NULL for net when wanting global, instead of net_mode ==
> VSOCK_NET_MODE_GLOBAL. This reflects the new logic
> of vsock_net_check_mode() that only requires net pointers (not
> net_mode).
>- refactor sysctl string code into a re-usable function, because
> child_ns_mode and ns_mode both handle the same strings.
>- remove redundant vsock_net_init(&init_net) call in module init because
> pernet registration calls the callback on the init_net too
>
>Changes in v12:
>- return true in dgram_allow(), stream_allow(), and seqpacket_allow()
> only if net_mode == VSOCK_NET_MODE_GLOBAL (Stefano)
>- document bind(VMADDR_CID_ANY) case in af_vsock.c (Stefano)
>- change order of stream_allow() call in vmci so we can pass vsk
> to it
>
>Changes in v10:
>- add file-level comment about what happens to sockets/devices
> when the namespace mode changes (Stefano)
>- change the 'if (write)' boolean in vsock_net_mode_string() to
> if (!write), this simplifies a later patch which adds "goto"
> for mutex unlocking on function exit.
>
>Changes in v9:
>- remove virtio_vsock_alloc_rx_skb() (Stefano)
>- remove vsock_global_dummy_net, not needed as net=NULL +
> net_mode=VSOCK_NET_MODE_GLOBAL achieves identical result
>
>Changes in v7:
>- hv_sock: fix hyperv build error
>- explain why vhost does not use the dummy
>- explain usage of __vsock_global_dummy_net
>- explain why VSOCK_NET_MODE_STR_MAX is 8 characters
>- use switch-case in vsock_net_mode_string()
>- avoid changing transports as much as possible
>- add vsock_find_{bound,connected}_socket_net()
>- rename `vsock_hdr` to `sysctl_hdr`
>- add virtio_vsock_alloc_linear_skb() wrapper for setting dummy net and
> global mode for virtio-vsock, move skb->cb zero-ing into wrapper
>- explain seqpacket_allow() change
>- move net setting to __vsock_create() instead of vsock_create() so
> that child sockets also have their net assigned upon accept()
>
>Changes in v6:
>- unregister sysctl ops in vsock_exit()
>- af_vsock: clarify description of CID behavior
>- af_vsock: fix buf vs buffer naming, and length checking
>- af_vsock: fix length checking w/ correct ctl_table->maxlen
>
>Changes in v5:
>- vsock_global_net() -> vsock_global_dummy_net()
>- update comments for new uAPI
>- use /proc/sys/net/vsock/ns_mode instead of /proc/net/vsock_ns_mode
>- add prototype changes so patch remains c)mpilable
>---
> Documentation/admin-guide/kernel-parameters.txt | 14 +
> MAINTAINERS | 1 +
> drivers/vhost/vsock.c | 6 +-
> include/linux/virtio_vsock.h | 4 +-
> include/net/af_vsock.h | 61 ++++-
> include/net/net_namespace.h | 4 +
> include/net/netns/vsock.h | 21 ++
> net/vmw_vsock/af_vsock.c | 328 ++++++++++++++++++++++--
> net/vmw_vsock/hyperv_transport.c | 7 +-
> net/vmw_vsock/virtio_transport.c | 9 +-
> net/vmw_vsock/virtio_transport_common.c | 6 +-
> net/vmw_vsock/vmci_transport.c | 26 +-
> net/vmw_vsock/vsock_loopback.c | 8 +-
> 13 files changed, 444 insertions(+), 51 deletions(-)
>
>diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>index a8d0afde7f85..b6e3bfe365a1 100644
>--- a/Documentation/admin-guide/kernel-parameters.txt
>+++ b/Documentation/admin-guide/kernel-parameters.txt
>@@ -8253,6 +8253,20 @@ Kernel parameters
> them quite hard to use for exploits but
> might break your system.
>
>+ vsock_init_ns_mode=
>+ [KNL,NET] Set the vsock namespace mode for the init
>+ (root) network namespace.
>+
>+ global [default] The init namespace operates in
>+ global mode where CIDs are system-wide and
>+ sockets can communicate across global
>+ namespaces.
>+
>+ local The init namespace operates in local mode
>+ where CIDs are private to the namespace and
>+ sockets can only communicate within the same
>+ namespace.
>+
My comment on v14 was more to start a discussion :-) sorry to not be
clear.
I briefly discussed it with Paolo in chat to better understand our
policy between cmdline parameters and module parameters, and it seems
that both are discouraged.
So he asked me if we have a use case for this, and thinking about it, I
don't have one at the moment. Also, if a user decides to set all netns
to local, whether init_net is local or global doesn't really matter,
right?
So perhaps before adding this, we should have a real use case.
Perhaps more than this feature, I would add a way to change the default
of all netns (including init_net) from global to local. But we can do
that later, since all netns have a way to understand what mode they are
in, so we don't break anything and the user has to explicitly change it,
knowing that they are breaking compatibility with pre-netns support.\
That said, at this point, maybe we can remove this, documenting that
init_net is always global, and if we have a use case in the future, we
can add this (or something else) to set the init_net mode (or change the
default for all netns).
Let's wait a bit before next version to wait a comment from Paolo or
Jakub on this. But I'm almost fine with both ways, so:
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
> vt.color= [VT] Default text color.
> Format: 0xYX, X = foreground, Y = background.
> Default: 0x07 = light gray on black.
[...]
>diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>index a3505a4dcee0..3fc8160d51df 100644
>--- a/net/vmw_vsock/af_vsock.c
>+++ b/net/vmw_vsock/af_vsock.c
[...]
>@@ -235,33 +303,42 @@ static void __vsock_remove_connected(struct
>vsock_sock *vsk)
> sock_put(&vsk->sk);
> }
>
In the v14 I suggested to add some documentation on top of the
vsock_find*() vs vsock_find_*_net() to explain better which one should
be used by transports.
Again is not a big deal, we can fix later if you don't need to resend.
Thanks,
Stefano
>-static struct sock *__vsock_find_bound_socket(struct sockaddr_vm *addr)
>+static struct sock *__vsock_find_bound_socket_net(struct sockaddr_vm *addr,
>+ struct net *net)
> {
> struct vsock_sock *vsk;
>
> list_for_each_entry(vsk, vsock_bound_sockets(addr), bound_table) {
>- if (vsock_addr_equals_addr(addr, &vsk->local_addr))
>- return sk_vsock(vsk);
>+ struct sock *sk = sk_vsock(vsk);
>+
>+ if (vsock_addr_equals_addr(addr, &vsk->local_addr) &&
>+ vsock_net_check_mode(sock_net(sk), net))
>+ return sk;
>
> if (addr->svm_port == vsk->local_addr.svm_port &&
> (vsk->local_addr.svm_cid == VMADDR_CID_ANY ||
>- addr->svm_cid == VMADDR_CID_ANY))
>- return sk_vsock(vsk);
>+ addr->svm_cid == VMADDR_CID_ANY) &&
>+ vsock_net_check_mode(sock_net(sk), net))
>+ return sk;
> }
>
> return NULL;
> }
>
>-static struct sock *__vsock_find_connected_socket(struct sockaddr_vm *src,
>- struct sockaddr_vm *dst)
>+static struct sock *
>+__vsock_find_connected_socket_net(struct sockaddr_vm *src,
>+ struct sockaddr_vm *dst, struct net *net)
> {
> struct vsock_sock *vsk;
>
> list_for_each_entry(vsk, vsock_connected_sockets(src, dst),
> connected_table) {
>+ struct sock *sk = sk_vsock(vsk);
>+
> if (vsock_addr_equals_addr(src, &vsk->remote_addr) &&
>- dst->svm_port == vsk->local_addr.svm_port) {
>- return sk_vsock(vsk);
>+ dst->svm_port == vsk->local_addr.svm_port &&
>+ vsock_net_check_mode(sock_net(sk), net)) {
>+ return sk;
> }
> }
>
>@@ -304,12 +381,13 @@ void vsock_remove_connected(struct vsock_sock *vsk)
> }
> EXPORT_SYMBOL_GPL(vsock_remove_connected);
>
>-struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr)
>+struct sock *vsock_find_bound_socket_net(struct sockaddr_vm *addr,
>+ struct net *net)
> {
> struct sock *sk;
>
> spin_lock_bh(&vsock_table_lock);
>- sk = __vsock_find_bound_socket(addr);
>+ sk = __vsock_find_bound_socket_net(addr, net);
> if (sk)
> sock_hold(sk);
>
>@@ -317,15 +395,22 @@ struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr)
>
> return sk;
> }
>+EXPORT_SYMBOL_GPL(vsock_find_bound_socket_net);
>+
>+struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr)
>+{
>+ return vsock_find_bound_socket_net(addr, NULL);
>+}
> EXPORT_SYMBOL_GPL(vsock_find_bound_socket);
>
>-struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
>- struct sockaddr_vm *dst)
>+struct sock *vsock_find_connected_socket_net(struct sockaddr_vm *src,
>+ struct sockaddr_vm *dst,
>+ struct net *net)
> {
> struct sock *sk;
>
> spin_lock_bh(&vsock_table_lock);
>- sk = __vsock_find_connected_socket(src, dst);
>+ sk = __vsock_find_connected_socket_net(src, dst, net);
> if (sk)
> sock_hold(sk);
>
>@@ -333,6 +418,13 @@ struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
>
> return sk;
> }
>+EXPORT_SYMBOL_GPL(vsock_find_connected_socket_net);
>+
>+struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
>+ struct sockaddr_vm *dst)
>+{
>+ return vsock_find_connected_socket_net(src, dst, NULL);
>+}
> EXPORT_SYMBOL_GPL(vsock_find_connected_socket);
>
> void vsock_remove_sock(struct vsock_sock *vsk)
On Wed, Jan 21, 2026 at 03:48:13PM +0100, Stefano Garzarella wrote:
> On Fri, Jan 16, 2026 at 01:28:41PM -0800, Bobby Eshleman wrote:
> > From: Bobby Eshleman <bobbyeshleman@meta.com>
> >
> > 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.
>
> nit: maybe we should mention here why we changed the random port allocation
>
> (not a big deal, only if you need to resend)
>
> >
> > 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 <bobbyeshleman@meta.com>
> > ---
> > Changes in v15:
> > - make static port in __vsock_bind_connectible per-netns
> > - remove __net_initdata because we want the ops beyond just boot
> > - add vsock_init_ns_mode kernel cmdline parameter to set init ns mode
> > - use if (ret || !write) in __vsock_net_mode_string() (Stefano)
> > - add vsock_net_mode_global() (Stefano)
> > - hide !net == VSOCK_NET_MODE_GLOBAL inside vsock_net_mode() (Stefano)
> > - clarify af_vsock.c comments on ns_mode/child_ns_mode (Stefano)
> >
> > Changes in v14:
> > - include linux/sysctl.h in af_vsock.c
> > - squash patch 'vsock: add per-net vsock NS mode state' into this patch
> > (prior version can be found here):
> > https://lore.kernel.org/all/20251223-vsock-vmtest-v13-1-9d6db8e7c80b@meta.com/)
> >
> > Changes in v13:
> > - remove net_mode and replace with direct accesses to net->vsock.mode,
> > since this is now immutable.
> > - update comments about mode behavior and mutability, and sysctl API
> > - only pass NULL for net when wanting global, instead of net_mode ==
> > VSOCK_NET_MODE_GLOBAL. This reflects the new logic
> > of vsock_net_check_mode() that only requires net pointers (not
> > net_mode).
> > - refactor sysctl string code into a re-usable function, because
> > child_ns_mode and ns_mode both handle the same strings.
> > - remove redundant vsock_net_init(&init_net) call in module init because
> > pernet registration calls the callback on the init_net too
> >
> > Changes in v12:
> > - return true in dgram_allow(), stream_allow(), and seqpacket_allow()
> > only if net_mode == VSOCK_NET_MODE_GLOBAL (Stefano)
> > - document bind(VMADDR_CID_ANY) case in af_vsock.c (Stefano)
> > - change order of stream_allow() call in vmci so we can pass vsk
> > to it
> >
> > Changes in v10:
> > - add file-level comment about what happens to sockets/devices
> > when the namespace mode changes (Stefano)
> > - change the 'if (write)' boolean in vsock_net_mode_string() to
> > if (!write), this simplifies a later patch which adds "goto"
> > for mutex unlocking on function exit.
> >
> > Changes in v9:
> > - remove virtio_vsock_alloc_rx_skb() (Stefano)
> > - remove vsock_global_dummy_net, not needed as net=NULL +
> > net_mode=VSOCK_NET_MODE_GLOBAL achieves identical result
> >
> > Changes in v7:
> > - hv_sock: fix hyperv build error
> > - explain why vhost does not use the dummy
> > - explain usage of __vsock_global_dummy_net
> > - explain why VSOCK_NET_MODE_STR_MAX is 8 characters
> > - use switch-case in vsock_net_mode_string()
> > - avoid changing transports as much as possible
> > - add vsock_find_{bound,connected}_socket_net()
> > - rename `vsock_hdr` to `sysctl_hdr`
> > - add virtio_vsock_alloc_linear_skb() wrapper for setting dummy net and
> > global mode for virtio-vsock, move skb->cb zero-ing into wrapper
> > - explain seqpacket_allow() change
> > - move net setting to __vsock_create() instead of vsock_create() so
> > that child sockets also have their net assigned upon accept()
> >
> > Changes in v6:
> > - unregister sysctl ops in vsock_exit()
> > - af_vsock: clarify description of CID behavior
> > - af_vsock: fix buf vs buffer naming, and length checking
> > - af_vsock: fix length checking w/ correct ctl_table->maxlen
> >
> > Changes in v5:
> > - vsock_global_net() -> vsock_global_dummy_net()
> > - update comments for new uAPI
> > - use /proc/sys/net/vsock/ns_mode instead of /proc/net/vsock_ns_mode
> > - add prototype changes so patch remains c)mpilable
> > ---
> > Documentation/admin-guide/kernel-parameters.txt | 14 +
> > MAINTAINERS | 1 +
> > drivers/vhost/vsock.c | 6 +-
> > include/linux/virtio_vsock.h | 4 +-
> > include/net/af_vsock.h | 61 ++++-
> > include/net/net_namespace.h | 4 +
> > include/net/netns/vsock.h | 21 ++
> > net/vmw_vsock/af_vsock.c | 328 ++++++++++++++++++++++--
> > net/vmw_vsock/hyperv_transport.c | 7 +-
> > net/vmw_vsock/virtio_transport.c | 9 +-
> > net/vmw_vsock/virtio_transport_common.c | 6 +-
> > net/vmw_vsock/vmci_transport.c | 26 +-
> > net/vmw_vsock/vsock_loopback.c | 8 +-
> > 13 files changed, 444 insertions(+), 51 deletions(-)
> >
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > index a8d0afde7f85..b6e3bfe365a1 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -8253,6 +8253,20 @@ Kernel parameters
> > them quite hard to use for exploits but
> > might break your system.
> >
> > + vsock_init_ns_mode=
> > + [KNL,NET] Set the vsock namespace mode for the init
> > + (root) network namespace.
> > +
> > + global [default] The init namespace operates in
> > + global mode where CIDs are system-wide and
> > + sockets can communicate across global
> > + namespaces.
> > +
> > + local The init namespace operates in local mode
> > + where CIDs are private to the namespace and
> > + sockets can only communicate within the same
> > + namespace.
> > +
>
> My comment on v14 was more to start a discussion :-) sorry to not be clear.
No worries, resending with this included started a good discussion so
not for nil.
>
> I briefly discussed it with Paolo in chat to better understand our policy
> between cmdline parameters and module parameters, and it seems that both are
> discouraged.
>
> So he asked me if we have a use case for this, and thinking about it, I
> don't have one at the moment. Also, if a user decides to set all netns to
> local, whether init_net is local or global doesn't really matter, right?
>
> So perhaps before adding this, we should have a real use case.
> Perhaps more than this feature, I would add a way to change the default of
> all netns (including init_net) from global to local. But we can do that
> later, since all netns have a way to understand what mode they are in, so we
> don't break anything and the user has to explicitly change it, knowing that
> they are breaking compatibility with pre-netns support.\
>
>
> That said, at this point, maybe we can remove this, documenting that
> init_net is always global, and if we have a use case in the future, we can
> add this (or something else) to set the init_net mode (or change the default
> for all netns).
>
> Let's wait a bit before next version to wait a comment from Paolo or Jakub
> on this. But I'm almost fine with both ways, so:
>
> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
>
> > vt.color= [VT] Default text color.
> > Format: 0xYX, X = foreground, Y = background.
> > Default: 0x07 = light gray on black.
>
> [...]
>
> > diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> > index a3505a4dcee0..3fc8160d51df 100644
> > --- a/net/vmw_vsock/af_vsock.c
> > +++ b/net/vmw_vsock/af_vsock.c
>
> [...]
>
> > @@ -235,33 +303,42 @@ static void __vsock_remove_connected(struct
> > vsock_sock *vsk)
> > sock_put(&vsk->sk);
> > }
> >
>
> In the v14 I suggested to add some documentation on top of the vsock_find*()
> vs vsock_find_*_net() to explain better which one should be used by
> transports.
>
> Again is not a big deal, we can fix later if you don't need to resend.
>
> Thanks,
> Stefano
Sorry about that slipping through the cracks, will add to v16.
I'll resend with:
1. revert init ns cmdline
2. update this message about why the port allocation changes
3. fix the vmtest missing ns arg bug that Kuba mentioned
4. update documentation on top of vsock_find* / vsock_find_*_net
5. update documentation on top of af_vsock.c w/ note about init_ns
having its mode fixed to global
Unless any prior feedback slipped, I think this captures everything
pending?
Best,
Bobby
On 1/21/26 3:48 PM, Stefano Garzarella wrote: >> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt >> index a8d0afde7f85..b6e3bfe365a1 100644 >> --- a/Documentation/admin-guide/kernel-parameters.txt >> +++ b/Documentation/admin-guide/kernel-parameters.txt >> @@ -8253,6 +8253,20 @@ Kernel parameters >> them quite hard to use for exploits but >> might break your system. >> >> + vsock_init_ns_mode= >> + [KNL,NET] Set the vsock namespace mode for the init >> + (root) network namespace. >> + >> + global [default] The init namespace operates in >> + global mode where CIDs are system-wide and >> + sockets can communicate across global >> + namespaces. >> + >> + local The init namespace operates in local mode >> + where CIDs are private to the namespace and >> + sockets can only communicate within the same >> + namespace. >> + > > My comment on v14 was more to start a discussion :-) sorry to not be > clear. > > I briefly discussed it with Paolo in chat to better understand our > policy between cmdline parameters and module parameters, and it seems > that both are discouraged. Double checking the git log it looks like __setup() usage is less constrained/restricted than what I thought. > So he asked me if we have a use case for this, and thinking about it, I > don't have one at the moment. Also, if a user decides to set all netns > to local, whether init_net is local or global doesn't really matter, > right? > > So perhaps before adding this, we should have a real use case. > Perhaps more than this feature, I would add a way to change the default > of all netns (including init_net) from global to local. But we can do > that later, since all netns have a way to understand what mode they are > in, so we don't break anything and the user has to explicitly change it, > knowing that they are breaking compatibility with pre-netns support.\ Lacking a clear use-case for vsock_init_ns_mode I tend to think it would be better to postpone its introduction. It should be easier to add it later than vice-versa. If there is a clear/well defined/known use-case, I guess the series can go as-is. /P
On Wed, Jan 21, 2026 at 05:32:34PM +0100, Paolo Abeni wrote: > On 1/21/26 3:48 PM, Stefano Garzarella wrote: > >> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > >> index a8d0afde7f85..b6e3bfe365a1 100644 > >> --- a/Documentation/admin-guide/kernel-parameters.txt > >> +++ b/Documentation/admin-guide/kernel-parameters.txt > >> @@ -8253,6 +8253,20 @@ Kernel parameters > >> them quite hard to use for exploits but > >> might break your system. > >> > >> + vsock_init_ns_mode= > >> + [KNL,NET] Set the vsock namespace mode for the init > >> + (root) network namespace. > >> + > >> + global [default] The init namespace operates in > >> + global mode where CIDs are system-wide and > >> + sockets can communicate across global > >> + namespaces. > >> + > >> + local The init namespace operates in local mode > >> + where CIDs are private to the namespace and > >> + sockets can only communicate within the same > >> + namespace. > >> + > > > > My comment on v14 was more to start a discussion :-) sorry to not be > > clear. > > > > I briefly discussed it with Paolo in chat to better understand our > > policy between cmdline parameters and module parameters, and it seems > > that both are discouraged. > > Double checking the git log it looks like __setup() usage is less > constrained/restricted than what I thought. > > > So he asked me if we have a use case for this, and thinking about it, I > > don't have one at the moment. Also, if a user decides to set all netns > > to local, whether init_net is local or global doesn't really matter, > > right? > > > > So perhaps before adding this, we should have a real use case. > > Perhaps more than this feature, I would add a way to change the default > > of all netns (including init_net) from global to local. But we can do > > that later, since all netns have a way to understand what mode they are > > in, so we don't break anything and the user has to explicitly change it, > > knowing that they are breaking compatibility with pre-netns support.\ > > Lacking a clear use-case for vsock_init_ns_mode I tend to think it would > be better to postpone its introduction. It should be easier to add it > later than vice-versa. > > If there is a clear/well defined/known use-case, I guess the series can > go as-is. > > /P > Our use case also does not need the ability to set the init ns mode, so I'll revert this bit. Thanks, Bobby
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