linux-stable.git/net/vmw_vsock, branch v5.6

vsock: fix potential deadlock in transport->release()

2020-02-27T20:03:56+00:00

Some transports (hyperv, virtio) acquire the sock lock during the
.release() callback.

In the vsock_stream_connect() we call vsock_assign_transport(); if
the socket was previously assigned to another transport, the
vsk->transport->release() is called, but the sock lock is already
held in the vsock_stream_connect(), causing a deadlock reported by
syzbot:

    INFO: task syz-executor280:9768 blocked for more than 143 seconds.
      Not tainted 5.6.0-rc1-syzkaller #0
    "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
    syz-executor280 D27912  9768   9766 0x00000000
    Call Trace:
     context_switch kernel/sched/core.c:3386 [inline]
     __schedule+0x934/0x1f90 kernel/sched/core.c:4082
     schedule+0xdc/0x2b0 kernel/sched/core.c:4156
     __lock_sock+0x165/0x290 net/core/sock.c:2413
     lock_sock_nested+0xfe/0x120 net/core/sock.c:2938
     virtio_transport_release+0xc4/0xd60 net/vmw_vsock/virtio_transport_common.c:832
     vsock_assign_transport+0xf3/0x3b0 net/vmw_vsock/af_vsock.c:454
     vsock_stream_connect+0x2b3/0xc70 net/vmw_vsock/af_vsock.c:1288
     __sys_connect_file+0x161/0x1c0 net/socket.c:1857
     __sys_connect+0x174/0x1b0 net/socket.c:1874
     __do_sys_connect net/socket.c:1885 [inline]
     __se_sys_connect net/socket.c:1882 [inline]
     __x64_sys_connect+0x73/0xb0 net/socket.c:1882
     do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
     entry_SYSCALL_64_after_hwframe+0x49/0xbe

To avoid this issue, this patch remove the lock acquiring in the
.release() callback of hyperv and virtio transports, and it holds
the lock when we call vsk->transport->release() in the vsock core.

Reported-by: syzbot+731710996d79d0d58fbc@syzkaller.appspotmail.com
Fixes: 408624af4c89 ("vsock: use local transport when it is loaded")
Signed-off-by: Stefano Garzarella 
Reviewed-by: Stefan Hajnoczi 
Signed-off-by: David S. Miller

Merge ra.kernel.org:/pub/scm/linux/kernel/git/netdev/net

2020-01-19T21:10:04+00:00

hv_sock: Remove the accept port restriction

2020-01-14T19:50:53+00:00

Currently, hv_sock restricts the port the guest socket can accept
connections on. hv_sock divides the socket port namespace into two parts
for server side (listening socket), 0-0x7FFFFFFF & 0x80000000-0xFFFFFFFF
(there are no restrictions on client port namespace). The first part
(0-0x7FFFFFFF) is reserved for sockets where connections can be accepted.
The second part (0x80000000-0xFFFFFFFF) is reserved for allocating ports
for the peer (host) socket, once a connection is accepted.
This reservation of the port namespace is specific to hv_sock and not
known by the generic vsock library (ex: af_vsock). This is problematic
because auto-binds/ephemeral ports are handled by the generic vsock
library and it has no knowledge of this port reservation and could
allocate a port that is not compatible with hv_sock (and legitimately so).
The issue hasn't surfaced so far because the auto-bind code of vsock
(__vsock_bind_stream) prior to the change 'VSOCK: bind to random port for
VMADDR_PORT_ANY' would start walking up from LAST_RESERVED_PORT (1023) and
start assigning ports. That will take a large number of iterations to hit
0x7FFFFFFF. But, after the above change to randomize port selection, the
issue has started coming up more frequently.
There has really been no good reason to have this port reservation logic
in hv_sock from the get go. Reserving a local port for peer ports is not
how things are handled generally. Peer ports should reflect the peer port.
This fixes the issue by lifting the port reservation, and also returns the
right peer port. Since the code converts the GUID to the peer port (by
using the first 4 bytes), there is a possibility of conflicts, but that
seems like a reasonable risk to take, given this is limited to vsock and
that only applies to all local sockets.

Signed-off-by: Sunil Muthuswamy 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2019-12-22T23:15:05+00:00

Mere overlapping changes in the conflicts here.

Signed-off-by: David S. Miller

vsock/virtio: add WARN_ON check on virtio_transport_get_ops()

2019-12-17T00:07:12+00:00

virtio_transport_get_ops() and virtio_transport_send_pkt_info()
can only be used on connecting/connected sockets, since a socket
assigned to a transport is required.

This patch adds a WARN_ON() on virtio_transport_get_ops() to check
this requirement, a comment and a returned error on
virtio_transport_send_pkt_info(),

Signed-off-by: Stefano Garzarella 
Signed-off-by: David S. Miller

vsock/virtio: fix null-pointer dereference in virtio_transport_recv_listen()

2019-12-17T00:07:12+00:00

With multi-transport support, listener sockets are not bound to any
transport. So, calling virtio_transport_reset(), when an error
occurs, on a listener socket produces the following null-pointer
dereference:

  BUG: kernel NULL pointer dereference, address: 00000000000000e8
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 0 P4D 0
  Oops: 0000 [#1] SMP PTI
  CPU: 0 PID: 20 Comm: kworker/0:1 Not tainted 5.5.0-rc1-ste-00003-gb4be21f316ac-dirty #56
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
  Workqueue: virtio_vsock virtio_transport_rx_work [vmw_vsock_virtio_transport]
  RIP: 0010:virtio_transport_send_pkt_info+0x20/0x130 [vmw_vsock_virtio_transport_common]
  Code: 1f 84 00 00 00 00 00 0f 1f 00 55 48 89 e5 41 57 41 56 41 55 49 89 f5 41 54 49 89 fc 53 48 83 ec 10 44 8b 76 20 e8 c0 ba fe ff <48> 8b 80 e8 00 00 00 e8 64 e3 7d c1 45 8b 45 00 41 8b 8c 24 d4 02
  RSP: 0018:ffffc900000b7d08 EFLAGS: 00010282
  RAX: 0000000000000000 RBX: ffff88807bf12728 RCX: 0000000000000000
  RDX: ffff88807bf12700 RSI: ffffc900000b7d50 RDI: ffff888035c84000
  RBP: ffffc900000b7d40 R08: ffff888035c84000 R09: ffffc900000b7d08
  R10: ffff8880781de800 R11: 0000000000000018 R12: ffff888035c84000
  R13: ffffc900000b7d50 R14: 0000000000000000 R15: ffff88807bf12724
  FS:  0000000000000000(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00000000000000e8 CR3: 00000000790f4004 CR4: 0000000000160ef0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   virtio_transport_reset+0x59/0x70 [vmw_vsock_virtio_transport_common]
   virtio_transport_recv_pkt+0x5bb/0xe50 [vmw_vsock_virtio_transport_common]
   ? detach_buf_split+0xf1/0x130
   virtio_transport_rx_work+0xba/0x130 [vmw_vsock_virtio_transport]
   process_one_work+0x1c0/0x300
   worker_thread+0x45/0x3c0
   kthread+0xfc/0x130
   ? current_work+0x40/0x40
   ? kthread_park+0x90/0x90
   ret_from_fork+0x35/0x40
  Modules linked in: sunrpc kvm_intel kvm vmw_vsock_virtio_transport vmw_vsock_virtio_transport_common irqbypass vsock virtio_rng rng_core
  CR2: 00000000000000e8
  ---[ end trace e75400e2ea2fa824 ]---

This happens because virtio_transport_reset() calls
virtio_transport_send_pkt_info() that can be used only on
connecting/connected sockets.

This patch fixes the issue, using virtio_transport_reset_no_sock()
instead of virtio_transport_reset() when we are handling a listener
socket.

Fixes: c0cfa2d8a788 ("vsock: add multi-transports support")
Signed-off-by: Stefano Garzarella 
Signed-off-by: David S. Miller

vsock/virtio: remove loopback handling

2019-12-11T23:01:23+00:00

We can remove the loopback handling from virtio_transport,
because now the vsock core is able to handle local communication
using the new vsock_loopback device.

Reviewed-by: Stefan Hajnoczi 
Signed-off-by: Stefano Garzarella 
Signed-off-by: David S. Miller

vsock: use local transport when it is loaded

2019-12-11T23:01:23+00:00

Now that we have a transport that can handle the local communication,
we can use it when it is loaded.

A socket will use the local transport (loopback) when the remote
CID is:
- equal to VMADDR_CID_LOCAL
- or equal to transport_g2h->get_local_cid(), if transport_g2h
  is loaded (this allows us to keep the same behavior implemented
  by virtio and vmci transports)
- or equal to VMADDR_CID_HOST, if transport_g2h is not loaded

Signed-off-by: Stefano Garzarella 
Signed-off-by: David S. Miller

vsock: add vsock_loopback transport

2019-12-11T23:01:23+00:00

This patch adds a new vsock_loopback transport to handle local
communication.
This transport is based on the loopback implementation of
virtio_transport, so it uses the virtio_transport_common APIs
to interface with the vsock core.

Signed-off-by: Stefano Garzarella 
Signed-off-by: David S. Miller

vsock: add local transport support in the vsock core

2019-12-11T23:01:23+00:00

This patch allows to register a transport able to handle
local communication (loopback).

Reviewed-by: Stefan Hajnoczi 
Signed-off-by: Stefano Garzarella 
Signed-off-by: David S. Miller