Commit 002c69e0 authored by Morten Siebuhr's avatar Morten Siebuhr Committed by Mikio Hara

net: fix looking up port numbers starting with numbers.

LookupPort() correctly parses service names beginning with numerals by
implementing a new parser, mainly taken from strconv/atoi.go.

Also testes some previously undefined behaviours around port numbers
larger than 65535 that previously could lead to some tests fail with
EOPNOTSUPP (Operation Not Supported).

Fixes #14322

Change-Id: I1b90dbed434494723e261d84e73fe705e5c0507a
Reviewed-on: https://go-review.googlesource.com/19720
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: default avatarMikio Hara <mikioh.mikioh@gmail.com>
parent b6b4004d
......@@ -112,13 +112,8 @@ func lookupIPContext(ctx context.Context, host string) (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 service == "" {
// Lock in the legacy behavior that an empty string
// means port 0. See Issue 13610.
return 0, nil
}
port, _, ok := dtoi(service, 0)
if !ok && port != big && port != -big {
port, needsLookup := parsePort(service)
if needsLookup {
port, err = lookupPort(network, service)
if err != nil {
return 0, err
......
......@@ -627,6 +627,7 @@ var lookupPortTests = []struct {
{"tcp", "65536", 0, false},
{"udp", "-1", 0, false},
{"udp", "65536", 0, false},
{"tcp", "123456789", 0, false},
// Issue 13610: LookupPort("tcp", "")
{"tcp", "", 0, true},
......@@ -647,7 +648,7 @@ func TestLookupPort(t *testing.T) {
for _, tt := range lookupPortTests {
if port, err := LookupPort(tt.network, tt.name); port != tt.port || (err == nil) != tt.ok {
t.Errorf("LookupPort(%q, %q) = %d, %v; want %d", tt.network, tt.name, port, err, tt.port)
t.Errorf("LookupPort(%q, %q) = %d, %v; want %d, error=%t", tt.network, tt.name, port, err, tt.port, !tt.ok)
}
}
}
// Copyright 2016 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.
package net
// parsePort parses service as a decimal interger and returns the
// corresponding value as port. It is the caller's responsibility to
// parse service as a non-decimal integer when needsLookup is true.
//
// Some system resolvers will return a valid port number when given a number
// over 65536 (see https://github.com/golang/go/issues/11715). Alas, the parser
// can't bail early on numbers > 65536. Therefore reasonably large/small
// numbers are parsed in full and rejected if invalid.
func parsePort(service string) (port int, needsLookup bool) {
if service == "" {
// Lock in the legacy behavior that an empty string
// means port 0. See golang.org/issue/13610.
return 0, false
}
const (
max = uint32(1<<32 - 1)
cutoff = uint32(1 << 30)
)
neg := false
if service[0] == '+' {
service = service[1:]
} else if service[0] == '-' {
neg = true
service = service[1:]
}
var n uint32
for _, d := range service {
if '0' <= d && d <= '9' {
d -= '0'
} else {
return 0, true
}
if n >= cutoff {
n = max
break
}
n *= 10
nn := n + uint32(d)
if nn < n || nn > max {
n = max
break
}
n = nn
}
if !neg && n >= cutoff {
port = int(cutoff - 1)
} else if neg && n > cutoff {
port = int(cutoff)
} else {
port = int(n)
}
if neg {
port = -port
}
return port, false
}
// Copyright 2016 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.
package net
import "testing"
var parsePortTests = []struct {
service string
port int
needsLookup bool
}{
{"", 0, false},
// Decimal number literals
{"-1073741825", -1 << 30, false},
{"-1073741824", -1 << 30, false},
{"-1073741823", -(1<<30 - 1), false},
{"-123456789", -123456789, false},
{"-1", -1, false},
{"-0", 0, false},
{"0", 0, false},
{"+0", 0, false},
{"+1", 1, false},
{"65535", 65535, false},
{"65536", 65536, false},
{"123456789", 123456789, false},
{"1073741822", 1<<30 - 2, false},
{"1073741823", 1<<30 - 1, false},
{"1073741824", 1<<30 - 1, false},
{"1073741825", 1<<30 - 1, false},
// Others
{"abc", 0, true},
{"9pfs", 0, true},
{"123badport", 0, true},
{"bad123port", 0, true},
{"badport123", 0, true},
{"123456789badport", 0, true},
{"-2147483649badport", 0, true},
{"2147483649badport", 0, true},
}
func TestParsePort(t *testing.T) {
// The following test cases are cribbed from the strconv
for _, tt := range parsePortTests {
if port, needsLookup := parsePort(tt.service); port != tt.port || needsLookup != tt.needsLookup {
t.Errorf("parsePort(%q) = %d, %t; want %d, %t", tt.service, port, needsLookup, tt.port, tt.needsLookup)
}
}
}
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