VSOCK: Send reset control packet when socket is partially bound

If a server side socket is bound to an address, but not in the listening
state yet, incoming connection requests should receive a reset control
packet in response. However, the function used to send the reset
silently drops the reset packet if the sending socket isn't bound
to a remote address (as is the case for a bound socket not yet in
the listening state). This change fixes this by using the src
of the incoming packet as destination for the reset packet in
this case.

Fixes: d021c344051a ("VSOCK: Introduce VM Sockets")
Reviewed-by: Adit Ranadive <aditr@vmware.com>
Reviewed-by: Vishnu Dasa <vdasa@vmware.com>
Signed-off-by: Jorgen Hansen <jhansen@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 50 insertions, 17 deletions

diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
index cb332adb84cd..c361ce782412 100644
--- a/net/vmw_vsock/vmci_transport.c
+++ b/net/vmw_vsock/vmci_transport.c
@@ -264,6 +264,31 @@ vmci_transport_send_control_pkt_bh(struct sockaddr_vm *src,
 }
 
 static int
+vmci_transport_alloc_send_control_pkt(struct sockaddr_vm *src,
+                                      struct sockaddr_vm *dst,
+                                      enum vmci_transport_packet_type type,
+                                      u64 size,
+                                      u64 mode,
+                                      struct vmci_transport_waiting_info *wait,
+                                      u16 proto,
+                                      struct vmci_handle handle)
+{
+        struct vmci_transport_packet *pkt;
+        int err;
+
+        pkt = kmalloc(sizeof(*pkt), GFP_KERNEL);
+        if (!pkt)
+                return -ENOMEM;
+
+        err = __vmci_transport_send_control_pkt(pkt, src, dst, type, size,
+                                                mode, wait, proto, handle,
+                                                true);
+        kfree(pkt);
+
+        return err;
+}
+
+static int
 vmci_transport_send_control_pkt(struct sock *sk,
                                 enum vmci_transport_packet_type type,
                                 u64 size,
@@ -272,9 +297,7 @@ vmci_transport_send_control_pkt(struct sock *sk,
                                 u16 proto,
                                 struct vmci_handle handle)
 {
-        struct vmci_transport_packet *pkt;
         struct vsock_sock *vsk;
-        int err;
 
         vsk = vsock_sk(sk);
 
@@ -284,17 +307,10 @@ vmci_transport_send_control_pkt(struct sock *sk,
         if (!vsock_addr_bound(&vsk->remote_addr))
                 return -EINVAL;
 
-        pkt = kmalloc(sizeof(*pkt), GFP_KERNEL);
-        if (!pkt)
-                return -ENOMEM;
-
-        err = __vmci_transport_send_control_pkt(pkt, &vsk->local_addr,
-                                                &vsk->remote_addr, type, size,
-                                                mode, wait, proto, handle,
-                                                true);
-        kfree(pkt);
-
-        return err;
+        return vmci_transport_alloc_send_control_pkt(&vsk->local_addr,
+                                                     &vsk->remote_addr,
+                                                     type, size, mode,
+                                                     wait, proto, handle);
 }
 
 static int vmci_transport_send_reset_bh(struct sockaddr_vm *dst,
@@ -312,12 +328,29 @@ static int vmci_transport_send_reset_bh(struct sockaddr_vm *dst,
 static int vmci_transport_send_reset(struct sock *sk,
                                      struct vmci_transport_packet *pkt)
 {
+        struct sockaddr_vm *dst_ptr;
+        struct sockaddr_vm dst;
+        struct vsock_sock *vsk;
+
         if (pkt->type == VMCI_TRANSPORT_PACKET_TYPE_RST)
                 return 0;
-        return vmci_transport_send_control_pkt(sk,
-                                        VMCI_TRANSPORT_PACKET_TYPE_RST,
-                                        0, 0, NULL, VSOCK_PROTO_INVALID,
-                                        VMCI_INVALID_HANDLE);
+
+        vsk = vsock_sk(sk);
+
+        if (!vsock_addr_bound(&vsk->local_addr))
+                return -EINVAL;
+
+        if (vsock_addr_bound(&vsk->remote_addr)) {
+                dst_ptr = &vsk->remote_addr;
+        } else {
+                vsock_addr_init(&dst, pkt->dg.src.context,
+                                pkt->src_port);
+                dst_ptr = &dst;
+        }
+        return vmci_transport_alloc_send_control_pkt(&vsk->local_addr, dst_ptr,
+                                             VMCI_TRANSPORT_PACKET_TYPE_RST,
+                                             0, 0, NULL, VSOCK_PROTO_INVALID,
+                                             VMCI_INVALID_HANDLE);
 }
 
 static int vmci_transport_send_negotiate(struct sock *sk, size_t size)