vsock/test: Cover more CIDs in transport_uaf test

vsock/test: Cover more CIDs in transport_uaf test

Increase the coverage of test for UAF due to socket unbinding, and losing
transport in general. It's a follow up to commit 301a62dfb0d0 ("vsock/test:
Add test for UAF due to socket unbinding") and discussion in [1].

The idea remains the same: take an unconnected stream socket with a
transport assigned and then attempt to switch the transport by trying (and
failing) to connect to some other CID. Now do this iterating over all the
well known CIDs (plus one).

While at it, drop the redundant synchronization between client and server.

Some single-transport setups can't be tested effectively; a warning is
issued. Depending on transports available, a variety of splats are possible
on unpatched machines. After reverting commit 78dafe1cf3af ("vsock: Orphan
socket after transport release") and commit fcdd2242c023 ("vsock: Keep the
binding until socket destruction"):

BUG: KASAN: slab-use-after-free in __vsock_bind+0x61f/0x720
Read of size 4 at addr ffff88811ff46b54 by task vsock_test/1475
Call Trace:
 dump_stack_lvl+0x68/0x90
 print_report+0x170/0x53d
 kasan_report+0xc2/0x180
 __vsock_bind+0x61f/0x720
 vsock_connect+0x727/0xc40
 __sys_connect+0xe8/0x100
 __x64_sys_connect+0x6e/0xc0
 do_syscall_64+0x92/0x1c0
 entry_SYSCALL_64_after_hwframe+0x4b/0x53

WARNING: CPU: 0 PID: 1475 at net/vmw_vsock/virtio_transport_common.c:37 virtio_transport_send_pkt_info+0xb2b/0x1160
Call Trace:
 virtio_transport_connect+0x90/0xb0
 vsock_connect+0x782/0xc40
 __sys_connect+0xe8/0x100
 __x64_sys_connect+0x6e/0xc0
 do_syscall_64+0x92/0x1c0
 entry_SYSCALL_64_after_hwframe+0x4b/0x53

KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
RIP: 0010:sock_has_perm+0xa7/0x2a0
Call Trace:
 selinux_socket_connect_helper.isra.0+0xbc/0x450
 selinux_socket_connect+0x3b/0x70
 security_socket_connect+0x31/0xd0
 __sys_connect_file+0x79/0x1f0
 __sys_connect+0xe8/0x100
 __x64_sys_connect+0x6e/0xc0
 do_syscall_64+0x92/0x1c0
 entry_SYSCALL_64_after_hwframe+0x4b/0x53

refcount_t: addition on 0; use-after-free.
WARNING: CPU: 7 PID: 1518 at lib/refcount.c:25 refcount_warn_saturate+0xdd/0x140
RIP: 0010:refcount_warn_saturate+0xdd/0x140
Call Trace:
 __vsock_bind+0x65e/0x720
 vsock_connect+0x727/0xc40
 __sys_connect+0xe8/0x100
 __x64_sys_connect+0x6e/0xc0
 do_syscall_64+0x92/0x1c0
 entry_SYSCALL_64_after_hwframe+0x4b/0x53

refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 1475 at lib/refcount.c:28 refcount_warn_saturate+0x12b/0x140
RIP: 0010:refcount_warn_saturate+0x12b/0x140
Call Trace:
 vsock_remove_bound+0x18f/0x280
 __vsock_release+0x371/0x480
 vsock_release+0x88/0x120
 __sock_release+0xaa/0x260
 sock_close+0x14/0x20
 __fput+0x35a/0xaa0
 task_work_run+0xff/0x1c0
 do_exit+0x849/0x24c0
 make_task_dead+0xf3/0x110
 rewind_stack_and_make_dead+0x16/0x20

[1]: https://lore.kernel.org/netdev/CAGxU2F5zhfWymY8u0hrKksW8PumXAYz-9_qRmW==92oAx1BX3g@mail.gmail.com/

Suggested-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://patch.msgid.link/20250611-vsock-test-inc-cov-v3-3-5834060d9c20@rbox.co
Signed-off-by: Jakub Kicinski <kuba@kernel.org>