net: make Dial, Listen{,Packet} for TCP/UDP with invalid port fail

This change makes Dial, Listen and ListenPacket with invalid port fail
whatever GODEBUG=netdns is.

Please be informed that cgoLookupPort with an out of range literal
number may return either the lower or upper bound value, 0 or 65535,
with no error on some platform.

Fixes #11715.

Change-Id: I43f9c4fb5526d1bf50b97698e0eb39d29fd74c35
Reviewed-on: https://go-review.googlesource.com/12447
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/net/error_test.go

@@ -116,8 +116,10 @@ var dialErrorTests = []struct {
 	{"tcp", "no-such-name:80"},
 	{"tcp", "mh/astro/r70:http"},
 
-	{"tcp", "127.0.0.1:0"},
+	{"tcp", JoinHostPort("127.0.0.1", "-1")},
-	{"udp", "127.0.0.1:0"},
+	{"tcp", JoinHostPort("127.0.0.1", "123456789")},
+	{"udp", JoinHostPort("127.0.0.1", "-1")},
+	{"udp", JoinHostPort("127.0.0.1", "123456789")},
 	{"ip:icmp", "127.0.0.1"},
 
 	{"unix", "/path/to/somewhere"},
@@ -145,10 +147,23 @@ func TestDialError(t *testing.T) {
 	for i, tt := range dialErrorTests {
 		c, err := d.Dial(tt.network, tt.address)
 		if err == nil {
-			t.Errorf("#%d: should fail; %s:%s->%s", i, tt.network, c.LocalAddr(), c.RemoteAddr())
+			t.Errorf("#%d: should fail; %s:%s->%s", i, c.LocalAddr().Network(), c.LocalAddr(), c.RemoteAddr())
 			c.Close()
 			continue
 		}
+		if tt.network == "tcp" || tt.network == "udp" {
+			nerr := err
+			if op, ok := nerr.(*OpError); ok {
+				nerr = op.Err
+			}
+			if sys, ok := nerr.(*os.SyscallError); ok {
+				nerr = sys.Err
+			}
+			if nerr == errOpNotSupported {
+				t.Errorf("#%d: should fail without %v; %s:%s->", i, nerr, tt.network, tt.address)
+				continue
+			}
+		}
 		if c != nil {
 			t.Errorf("Dial returned non-nil interface %T(%v) with err != nil", c, c)
 		}
@@ -198,7 +213,8 @@ var listenErrorTests = []struct {
 	{"tcp", "no-such-name:80"},
 	{"tcp", "mh/astro/r70:http"},
 
-	{"tcp", "127.0.0.1:0"},
+	{"tcp", JoinHostPort("127.0.0.1", "-1")},
+	{"tcp", JoinHostPort("127.0.0.1", "123456789")},
 
 	{"unix", "/path/to/somewhere"},
 	{"unixpacket", "/path/to/somewhere"},
@@ -223,10 +239,23 @@ func TestListenError(t *testing.T) {
 	for i, tt := range listenErrorTests {
 		ln, err := Listen(tt.network, tt.address)
 		if err == nil {
-			t.Errorf("#%d: should fail; %s:%s->", i, tt.network, ln.Addr())
+			t.Errorf("#%d: should fail; %s:%s->", i, ln.Addr().Network(), ln.Addr())
 			ln.Close()
 			continue
 		}
+		if tt.network == "tcp" {
+			nerr := err
+			if op, ok := nerr.(*OpError); ok {
+				nerr = op.Err
+			}
+			if sys, ok := nerr.(*os.SyscallError); ok {
+				nerr = sys.Err
+			}
+			if nerr == errOpNotSupported {
+				t.Errorf("#%d: should fail without %v; %s:%s->", i, nerr, tt.network, tt.address)
+				continue
+			}
+		}
 		if ln != nil {
 			t.Errorf("Listen returned non-nil interface %T(%v) with err != nil", ln, ln)
 		}
@@ -246,6 +275,9 @@ var listenPacketErrorTests = []struct {
 	{"udp", "127.0.0.1:☺"},
 	{"udp", "no-such-name:80"},
 	{"udp", "mh/astro/r70:http"},
+
+	{"udp", JoinHostPort("127.0.0.1", "-1")},
+	{"udp", JoinHostPort("127.0.0.1", "123456789")},
 }
 
 func TestListenPacketError(t *testing.T) {
@@ -263,7 +295,7 @@ func TestListenPacketError(t *testing.T) {
 	for i, tt := range listenPacketErrorTests {
 		c, err := ListenPacket(tt.network, tt.address)
 		if err == nil {
-			t.Errorf("#%d: should fail; %s:%s->", i, tt.network, c.LocalAddr())
+			t.Errorf("#%d: should fail; %s:%s->", i, c.LocalAddr().Network(), c.LocalAddr())
 			c.Close()
 			continue
 		}

src/net/ipsock.go

@@ -213,7 +213,7 @@ func internetAddrList(net, addr string, deadline time.Time) (addrList, error) {
 			if host, port, err = SplitHostPort(addr); err != nil {
 				return nil, err
 			}
-			if portnum, err = parsePort(net, port); err != nil {
+			if portnum, err = LookupPort(net, port); err != nil {
 				return nil, err
 			}
 		}

src/net/lookup.go

@@ -123,10 +123,17 @@ func lookupIPDeadline(host string, deadline time.Time) (addrs []IPAddr, err erro
 
 // LookupPort looks up the port for the given network and service.
 func LookupPort(network, service string) (port int, err error) {
-	if n, i, ok := dtoi(service, 0); ok && i == len(service) {
+	port, _, ok := dtoi(service, 0)
-		return n, nil
+	if !ok && port != big && port != -big {
+		port, err = lookupPort(network, service)
+		if err != nil {
+			return 0, err
 		}
-	return lookupPort(network, service)
+	}
+	if 0 > port || port > 65535 {
+		return 0, &AddrError{Err: "invalid port", Addr: service}
+	}
+	return port, nil
 }
 
 // LookupCNAME returns the canonical DNS host for the given name.

src/net/parse.go

@@ -118,15 +118,27 @@ const big = 0xFFFFFF
 // Returns number, new offset, success.
 func dtoi(s string, i0 int) (n int, i int, ok bool) {
 	n = 0
+	neg := false
+	if len(s) > 0 && s[0] == '-' {
+		neg = true
+		s = s[1:]
+	}
 	for i = i0; i < len(s) && '0' <= s[i] && s[i] <= '9'; i++ {
 		n = n*10 + int(s[i]-'0')
 		if n >= big {
-			return 0, i, false
+			if neg {
+				return -big, i + 1, false
+			}
+			return big, i, false
 		}
 	}
 	if i == i0 {
 		return 0, i, false
 	}
+	if neg {
+		n = -n
+		i++
+	}
 	return n, i, true
 }
 

src/net/parse_test.go

@@ -77,3 +77,25 @@ func TestGoDebugString(t *testing.T) {
 		}
 	}
 }
+
+func TestDtoi(t *testing.T) {
+	for _, tt := range []struct {
+		in  string
+		out int
+		off int
+		ok  bool
+	}{
+		{"", 0, 0, false},
+
+		{"-123456789", -big, 9, false},
+		{"-1", -1, 2, true},
+		{"0", 0, 1, true},
+		{"65536", 65536, 5, true},
+		{"123456789", big, 8, false},
+	} {
+		n, i, ok := dtoi(tt.in, 0)
+		if n != tt.out || i != tt.off || ok != tt.ok {
+			t.Errorf("got %d, %d, %v; want %d, %d, %v", n, i, ok, tt.out, tt.off, tt.ok)
+		}
+	}
+}

src/net/port.go

@@ -1,24 +0,0 @@
-// Copyright 2012 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Network service port manipulations
-
-package net
-
-// parsePort parses port as a network service port number for both
-// TCP and UDP.
-func parsePort(net, port string) (int, error) {
-	p, i, ok := dtoi(port, 0)
-	if !ok || i != len(port) {
-		var err error
-		p, err = LookupPort(net, port)
-		if err != nil {
-			return 0, err
-		}
-	}
-	if p < 0 || p > 0xFFFF {
-		return 0, &AddrError{Err: "invalid port", Addr: port}
-	}
-	return p, nil
-}

src/net/port_test.go

@@ -9,12 +9,13 @@ import (
 	"testing"
 )
 
-var portTests = []struct {
+var lookupPortTests = []struct {
 	network string
 	name    string
 	port    int
 	ok      bool
 }{
+	{"tcp", "0", 0, true},
 	{"tcp", "echo", 7, true},
 	{"tcp", "discard", 9, true},
 	{"tcp", "systat", 11, true},
@@ -29,6 +30,7 @@ var portTests = []struct {
 	{"tcp", "finger", 79, true},
 	{"tcp", "42", 42, true},
 
+	{"udp", "0", 0, true},
 	{"udp", "echo", 7, true},
 	{"udp", "tftp", 69, true},
 	{"udp", "bootpc", 68, true},
@@ -41,6 +43,10 @@ var portTests = []struct {
 
 	{"--badnet--", "zzz", 0, false},
 	{"tcp", "--badport--", 0, false},
+	{"tcp", "-1", 0, false},
+	{"tcp", "65536", 0, false},
+	{"udp", "-1", 0, false},
+	{"udp", "65536", 0, false},
 }
 
 func TestLookupPort(t *testing.T) {
@@ -49,9 +55,9 @@ func TestLookupPort(t *testing.T) {
 		t.Skipf("not supported on %s", runtime.GOOS)
 	}
 
-	for _, tt := range portTests {
+	for _, tt := range lookupPortTests {
 		if port, err := LookupPort(tt.network, tt.name); port != tt.port || (err == nil) != tt.ok {
-			t.Errorf("LookupPort(%q, %q) = %v, %v; want %v", tt.network, tt.name, port, err, tt.port)
+			t.Errorf("LookupPort(%q, %q) = %d, %v; want %d", tt.network, tt.name, port, err, tt.port)
 		}
 	}
 }