cmd/stdiscosrv: Be more picky about allowed addresses (fixes #5151) (#5153)

Filter out ludicrous stuff both from explicitly announced addresses and
potential automatic replacements.
This commit is contained in:
Jakob Borg 2018-08-30 19:06:35 +02:00 committed by Audrius Butkevicius
parent 916182bc73
commit e384c822b6
2 changed files with 79 additions and 0 deletions

View File

@ -335,7 +335,21 @@ func fixupAddresses(remote net.IP, addresses []string) []string {
}
ip := net.ParseIP(host)
// Some classes of IP are no-go.
if ip.IsLoopback() || ip.IsMulticast() {
continue
}
if host == "" || ip.IsUnspecified() {
// Replace the unspecified IP with the request source.
// ... unless the request source is the loopback address or
// multicast/unspecified (can't happen, really).
if remote.IsLoopback() || remote.IsMulticast() || remote.IsUnspecified() {
continue
}
// Do not use IPv6 remote address if requested scheme is ...4
// (i.e., tcp4, etc.)
if strings.HasSuffix(uri.Scheme, "4") && remote.To4() == nil {

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@ -0,0 +1,65 @@
// Copyright (C) 2018 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
package main
import (
"fmt"
"net"
"testing"
)
func TestFixupAddresses(t *testing.T) {
cases := []struct {
remote net.IP
in []string
out []string
}{
{ // verbatim passthrough
in: []string{"tcp://1.2.3.4:22000"},
out: []string{"tcp://1.2.3.4:22000"},
}, { // unspecified replaced by remote
remote: net.ParseIP("1.2.3.4"),
in: []string{"tcp://:22000", "tcp://192.0.2.42:22000"},
out: []string{"tcp://1.2.3.4:22000", "tcp://192.0.2.42:22000"},
}, { // unspecified not used as replacement
remote: net.ParseIP("0.0.0.0"),
in: []string{"tcp://:22000", "tcp://192.0.2.42:22000"},
out: []string{"tcp://192.0.2.42:22000"},
}, { // unspecified not used as replacement
remote: net.ParseIP("::"),
in: []string{"tcp://:22000", "tcp://192.0.2.42:22000"},
out: []string{"tcp://192.0.2.42:22000"},
}, { // localhost not used as replacement
remote: net.ParseIP("127.0.0.1"),
in: []string{"tcp://:22000", "tcp://192.0.2.42:22000"},
out: []string{"tcp://192.0.2.42:22000"},
}, { // localhost not used as replacement
remote: net.ParseIP("::1"),
in: []string{"tcp://:22000", "tcp://192.0.2.42:22000"},
out: []string{"tcp://192.0.2.42:22000"},
}, { // multicast not used as replacement
remote: net.ParseIP("224.0.0.1"),
in: []string{"tcp://:22000", "tcp://192.0.2.42:22000"},
out: []string{"tcp://192.0.2.42:22000"},
}, { // multicast not used as replacement
remote: net.ParseIP("ff80::42"),
in: []string{"tcp://:22000", "tcp://192.0.2.42:22000"},
out: []string{"tcp://192.0.2.42:22000"},
}, { // explicitly announced weirdness is also filtered
remote: net.ParseIP("192.0.2.42"),
in: []string{"tcp://:22000", "tcp://127.1.2.3:22000", "tcp://[::1]:22000", "tcp://[ff80::42]:22000"},
out: []string{"tcp://192.0.2.42:22000"},
},
}
for _, tc := range cases {
out := fixupAddresses(tc.remote, tc.in)
if fmt.Sprint(out) != fmt.Sprint(tc.out) {
t.Errorf("fixupAddresses(%v, %v) => %v, expected %v", tc.remote, tc.in, out, tc.out)
}
}
}