fix default listen/listenany port (JuliaLang#23699)

secure default is to listen on localhost only
(as documented)

fix JuliaLang#23607

base/socket.jl

@@ -701,7 +701,7 @@ function getipaddr()
  end
  end
  ccall(:uv_free_interface_addresses, Void, (Ptr{UInt8}, Int32), addr, count)
- return lo_present ? ip"127.0.0.1" : error("No networking interface available")
+ return lo_present ? localhost : error("No networking interface available")
 end
 
 ##
@@ -741,15 +741,15 @@ connect!(sock::TCPSocket, addr::InetAddr) = connect!(sock, addr.host, addr.port)
 
 Connect to the host `host` on port `port`.
 """
-connect(sock::TCPSocket, port::Integer) = connect(sock,IPv4(127,0,0,1), port)
-connect(port::Integer) = connect(IPv4(127,0,0,1), port)
+connect(sock::TCPSocket, port::Integer) = connect(sock, localhost, port)
+connect(port::Integer) = connect(localhost, port)
 
 # Valid connect signatures for TCP
 connect(host::AbstractString, port::Integer) = connect(TCPSocket(), host, port)
 connect(addr::IPAddr, port::Integer) = connect(TCPSocket(), addr, port)
 connect(addr::InetAddr) = connect(TCPSocket(), addr)
 
-default_connectcb(sock,status) = nothing
+default_connectcb(sock, status) = nothing
 
 function connect!(sock::TCPSocket, host::AbstractString, port::Integer)
  if sock.status != StatusInit
@@ -780,7 +780,7 @@ function listen(addr; backlog::Integer=BACKLOG_DEFAULT)
  listen(sock; backlog=backlog)
  return sock
 end
-listen(port::Integer; backlog::Integer=BACKLOG_DEFAULT) = listen(IPv4(UInt32(0)), port; backlog=backlog)
+listen(port::Integer; backlog::Integer=BACKLOG_DEFAULT) = listen(localhost, port; backlog=backlog)
 listen(host::IPAddr, port::Integer; backlog::Integer=BACKLOG_DEFAULT) = listen(InetAddr(host, port); backlog=backlog)
 
 function listen(callback, server::Union{TCPSocket, UDPSocket})
@@ -822,6 +822,8 @@ end
 
 ## Utility functions
 
+const localhost = ip"127.0.0.1"
+
 """
  listenany([host::IPAddr,] port_hint) -> (UInt16, TCPServer)
 
@@ -847,7 +849,7 @@ function listenany(host::IPAddr, default_port)
  end
 end
 
-listenany(default_port) = listenany(IPv4(UInt32(0)), default_port)
+listenany(default_port) = listenany(localhost, default_port)
 
 """
  getsockname(sock::Union{TCPServer, TCPSocket}) -> (IPAddr, UInt16)

test/socket.jl

@@ -73,23 +73,46 @@ defaultport = rand(2000:4000)
 for testport in [0, defaultport]
  port = Channel(1)
  tsk = @async begin
- p, s = listenany(testport)
+ local (p, s) = listenany(testport)
+ @test p != 0
+ @test getsockname(s) == (Base.localhost, p)
  put!(port, p)
- sock = accept(s)
- # test write call
- write(sock,"Hello World\n")
-
- # test "locked" println to a socket
- @sync begin
- for i in 1:100
- @async println(sock, "a", 1)
+ for i in 1:3
+ sock = accept(s)
+ @test getsockname(sock) == (Base.localhost, p)
+ let peer = getpeername(sock)::Tuple{IPAddr, UInt16}
+ @test peer[1] == Base.localhost
+ @test 0 != peer[2] != p
  end
+ # test write call
+ write(sock, "Hello World\n")
+
+ # test "locked" println to a socket
+ @sync begin
+ for i in 1:100
+ @async println(sock, "a", 1)
+ end
+ end
+ close(sock)
  end
  close(s)
- close(sock)
  end
  wait(port)
- @test read(connect(fetch(port)), String) == "Hello World\n" * ("a1\n"^100)
+ let p = fetch(port)
+ otherip = getipaddr()
+ if otherip != Base.localhost
+ @test_throws Base.UVError("connect", Base.UV_ECONNREFUSED) connect(otherip, p)
+ end
+ for i in 1:3
+ client = connect(p)
+ let name = getsockname(client)::Tuple{IPAddr, UInt16}
+ @test name[1] == Base.localhost
+ @test 0 != name[2] != p
+ end
+ @test getpeername(client) == (Base.localhost, p)
+ @test read(client, String) == "Hello World\n" * ("a1\n"^100)
+ end
+ end
  wait(tsk)
 end