--- /dev/null
+From ce137a90f152310d37d032e54c0bce36ab96e9d4 Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Fri, 24 Jan 2020 03:08:18 +0000
+Subject: hv_sock: Remove the accept port restriction
+
+From: Sunil Muthuswamy <sunilmut@microsoft.com>
+
+[ Upstream commit c742c59e1fbd022b64d91aa9a0092b3a699d653c ]
+
+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 <sunilmut@microsoft.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ net/vmw_vsock/hyperv_transport.c | 68 +++++---------------------------
+ 1 file changed, 9 insertions(+), 59 deletions(-)
+
+diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
+index 6614512f81800..736b76ec8cf01 100644
+--- a/net/vmw_vsock/hyperv_transport.c
++++ b/net/vmw_vsock/hyperv_transport.c
+@@ -144,28 +144,15 @@ struct hvsock {
+ ****************************************************************************
+ * The only valid Service GUIDs, from the perspectives of both the host and *
+ * Linux VM, that can be connected by the other end, must conform to this *
+- * format: <port>-facb-11e6-bd58-64006a7986d3, and the "port" must be in *
+- * this range [0, 0x7FFFFFFF]. *
++ * format: <port>-facb-11e6-bd58-64006a7986d3. *
+ ****************************************************************************
+ *
+ * When we write apps on the host to connect(), the GUID ServiceID is used.
+ * When we write apps in Linux VM to connect(), we only need to specify the
+ * port and the driver will form the GUID and use that to request the host.
+ *
+- * From the perspective of Linux VM:
+- * 1. the local ephemeral port (i.e. the local auto-bound port when we call
+- * connect() without explicit bind()) is generated by __vsock_bind_stream(),
+- * and the range is [1024, 0xFFFFFFFF).
+- * 2. the remote ephemeral port (i.e. the auto-generated remote port for
+- * a connect request initiated by the host's connect()) is generated by
+- * hvs_remote_addr_init() and the range is [0x80000000, 0xFFFFFFFF).
+ */
+
+-#define MAX_LISTEN_PORT ((u32)0x7FFFFFFF)
+-#define MAX_VM_LISTEN_PORT MAX_LISTEN_PORT
+-#define MAX_HOST_LISTEN_PORT MAX_LISTEN_PORT
+-#define MIN_HOST_EPHEMERAL_PORT (MAX_HOST_LISTEN_PORT + 1)
+-
+ /* 00000000-facb-11e6-bd58-64006a7986d3 */
+ static const uuid_le srv_id_template =
+ UUID_LE(0x00000000, 0xfacb, 0x11e6, 0xbd, 0x58,
+@@ -188,33 +175,6 @@ static void hvs_addr_init(struct sockaddr_vm *addr, const uuid_le *svr_id)
+ vsock_addr_init(addr, VMADDR_CID_ANY, port);
+ }
+
+-static void hvs_remote_addr_init(struct sockaddr_vm *remote,
+- struct sockaddr_vm *local)
+-{
+- static u32 host_ephemeral_port = MIN_HOST_EPHEMERAL_PORT;
+- struct sock *sk;
+-
+- vsock_addr_init(remote, VMADDR_CID_ANY, VMADDR_PORT_ANY);
+-
+- while (1) {
+- /* Wrap around ? */
+- if (host_ephemeral_port < MIN_HOST_EPHEMERAL_PORT ||
+- host_ephemeral_port == VMADDR_PORT_ANY)
+- host_ephemeral_port = MIN_HOST_EPHEMERAL_PORT;
+-
+- remote->svm_port = host_ephemeral_port++;
+-
+- sk = vsock_find_connected_socket(remote, local);
+- if (!sk) {
+- /* Found an available ephemeral port */
+- return;
+- }
+-
+- /* Release refcnt got in vsock_find_connected_socket */
+- sock_put(sk);
+- }
+-}
+-
+ static void hvs_set_channel_pending_send_size(struct vmbus_channel *chan)
+ {
+ set_channel_pending_send_size(chan,
+@@ -342,12 +302,7 @@ static void hvs_open_connection(struct vmbus_channel *chan)
+ if_type = &chan->offermsg.offer.if_type;
+ if_instance = &chan->offermsg.offer.if_instance;
+ conn_from_host = chan->offermsg.offer.u.pipe.user_def[0];
+-
+- /* The host or the VM should only listen on a port in
+- * [0, MAX_LISTEN_PORT]
+- */
+- if (!is_valid_srv_id(if_type) ||
+- get_port_by_srv_id(if_type) > MAX_LISTEN_PORT)
++ if (!is_valid_srv_id(if_type))
+ return;
+
+ hvs_addr_init(&addr, conn_from_host ? if_type : if_instance);
+@@ -372,6 +327,13 @@ static void hvs_open_connection(struct vmbus_channel *chan)
+
+ new->sk_state = TCP_SYN_SENT;
+ vnew = vsock_sk(new);
++
++ hvs_addr_init(&vnew->local_addr, if_type);
++
++ /* Remote peer is always the host */
++ vsock_addr_init(&vnew->remote_addr,
++ VMADDR_CID_HOST, VMADDR_PORT_ANY);
++ vnew->remote_addr.svm_port = get_port_by_srv_id(if_instance);
+ hvs_new = vnew->trans;
+ hvs_new->chan = chan;
+ } else {
+@@ -411,8 +373,6 @@ static void hvs_open_connection(struct vmbus_channel *chan)
+ sk->sk_ack_backlog++;
+
+ hvs_addr_init(&vnew->local_addr, if_type);
+- hvs_remote_addr_init(&vnew->remote_addr, &vnew->local_addr);
+-
+ hvs_new->vm_srv_id = *if_type;
+ hvs_new->host_srv_id = *if_instance;
+
+@@ -717,16 +677,6 @@ static bool hvs_stream_is_active(struct vsock_sock *vsk)
+
+ static bool hvs_stream_allow(u32 cid, u32 port)
+ {
+- /* The host's port range [MIN_HOST_EPHEMERAL_PORT, 0xFFFFFFFF) is
+- * reserved as ephemeral ports, which are used as the host's ports
+- * when the host initiates connections.
+- *
+- * Perform this check in the guest so an immediate error is produced
+- * instead of a timeout.
+- */
+- if (port > MAX_HOST_LISTEN_PORT)
+- return false;
+-
+ if (cid == VMADDR_CID_HOST)
+ return true;
+
+--
+2.20.1
+
projects / thirdparty / kernel / stable-queue.git / commitdiff
