[PATCH RFC net v2 3/3] vsock: Fix IOCTL_VM_SOCKETS_GET_LOCAL_CID to check also `transport_local`
From: Michal Luczaj <hidden>
Date: 2025-06-20 19:53:04
Also in:
lkml, virtualization
Subsystem:
networking [general], the rest, vm sockets (af_vsock) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Stefano Garzarella
Support returning VMADDR_CID_LOCAL in case no other vsock transport is
available.
Fixes: 0e12190578d0 ("vsock: add local transport support in the vsock core")
Suggested-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Michal Luczaj <redacted>
---
man vsock(7) mentions IOCTL_VM_SOCKETS_GET_LOCAL_CID vs. VMADDR_CID_LOCAL:
Ioctls
...
IOCTL_VM_SOCKETS_GET_LOCAL_CID
...
Consider using VMADDR_CID_ANY when binding instead of
getting the local CID with IOCTL_VM_SOCKETS_GET_LOCAL_CID.
Local communication
....
The local CID obtained with IOCTL_VM_SOCKETS_GET_LOCAL_CID can be
used for the same purpose, but it is preferable to use
VMADDR_CID_LOCAL.
I was wondering it that would need some rewriting, since we're adding
VMADDR_CID_LOCAL as a possible ioctl's return value.
---
net/vmw_vsock/af_vsock.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index a1b1073a2c89f865fcdb58b38d8e7feffcf1544f..4bdb4016bd14d790f3d217d5063be64a1553b194 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c@@ -2577,6 +2577,8 @@ static long vsock_dev_do_ioctl(struct file *filp, cid = vsock_transport_local_cid(&transport_g2h); if (cid == VMADDR_CID_ANY) cid = vsock_transport_local_cid(&transport_h2g); + if (cid == VMADDR_CID_ANY && transport_local) + cid = VMADDR_CID_LOCAL; if (put_user(cid, p) != 0) retval = -EFAULT;
--
2.49.0