From e849b3e1192f94f14f6ea0e0af50275956689171 Mon Sep 17 00:00:00 2001 From: Neil Alexander Date: Fri, 8 May 2020 23:23:48 +0100 Subject: [PATCH] Initial support for pinning public keys in peering strings --- src/yggdrasil/link.go | 57 +++++++++++++++++++++++++++++++++++++------ src/yggdrasil/tcp.go | 42 ++++++++++++++++++------------- 2 files changed, 75 insertions(+), 24 deletions(-) diff --git a/src/yggdrasil/link.go b/src/yggdrasil/link.go index 157ea52..c0ae23b 100644 --- a/src/yggdrasil/link.go +++ b/src/yggdrasil/link.go @@ -1,6 +1,7 @@ package yggdrasil import ( + "bytes" "encoding/hex" "errors" "fmt" @@ -50,6 +51,7 @@ type linkInterface struct { name string link *link peer *peer + options linkOptions msgIO linkInterfaceMsgIO info linkInfo incoming bool @@ -67,6 +69,10 @@ type linkInterface struct { unstalled bool // False if an idle notification to the switch hasn't been sent because we stalled (or are first starting up) } +type linkOptions struct { + pinningInfo *url.Userinfo +} + func (l *link) init(c *Core) error { l.core = c l.mutex.Lock() @@ -92,13 +98,19 @@ func (l *link) call(uri string, sintf string) error { return fmt.Errorf("peer %s is not correctly formatted (%s)", uri, err) } pathtokens := strings.Split(strings.Trim(u.Path, "/"), "/") + tcpOpts := tcpOptions{} + if u.User != nil { + tcpOpts.pinningInfo = u.User + } switch u.Scheme { case "tcp": - l.tcp.call(u.Host, nil, sintf, nil) + l.tcp.call(u.Host, tcpOpts, sintf) case "socks": - l.tcp.call(pathtokens[0], u.Host, sintf, nil) + tcpOpts.socksProxyAddr = u.Host + l.tcp.call(pathtokens[0], tcpOpts, sintf) case "tls": - l.tcp.call(u.Host, nil, sintf, l.tcp.tls.forDialer) + tcpOpts.upgrade = l.tcp.tls.forDialer + l.tcp.call(u.Host, tcpOpts, sintf) default: return errors.New("unknown call scheme: " + u.Scheme) } @@ -122,12 +134,13 @@ func (l *link) listen(uri string) error { } } -func (l *link) create(msgIO linkInterfaceMsgIO, name, linkType, local, remote string, incoming, force bool) (*linkInterface, error) { +func (l *link) create(msgIO linkInterfaceMsgIO, name, linkType, local, remote string, incoming, force bool, options linkOptions) (*linkInterface, error) { // Technically anything unique would work for names, but let's pick something human readable, just for debugging intf := linkInterface{ - name: name, - link: l, - msgIO: msgIO, + name: name, + link: l, + options: options, + msgIO: msgIO, info: linkInfo{ linkType: linkType, local: local, @@ -181,6 +194,36 @@ func (intf *linkInterface) handler() error { intf.link.core.log.Errorln("Failed to connect to node: " + intf.name + " version: " + fmt.Sprintf("%d.%d", meta.ver, meta.minorVer)) return errors.New("failed to connect: wrong version") } + // Check if the remote side matches the keys we expected. This is a bit of a weak + // check - in future versions we really should check a signature or something like that. + if pinning := intf.options.pinningInfo; pinning != nil { + allowed := true + keytype := pinning.Username() + if pubkey, ok := pinning.Password(); ok { + switch keytype { + case "curve25519": + boxPub, err := hex.DecodeString(pubkey) + if err != nil || len(boxPub) != crypto.BoxPubKeyLen { + allowed = false + break + } + allowed = bytes.Compare(boxPub, meta.box[:]) == 0 + case "ed25519": + sigPub, err := hex.DecodeString(pubkey) + if err != nil || len(sigPub) != crypto.SigPubKeyLen { + allowed = false + break + } + allowed = bytes.Compare(sigPub, meta.sig[:]) == 0 + } + } else { + allowed = false + } + if !allowed { + intf.link.core.log.Errorf("Failed to connect to node: %q sent key that does not match pinned %q key", intf.name, keytype) + return fmt.Errorf("failed to connect: host does not match pinned %q key", pinning.Username()) + } + } // Check if we're authorized to connect to this key / IP if intf.incoming && !intf.force && !intf.link.core.peers.isAllowedEncryptionPublicKey(&meta.box) { intf.link.core.log.Warnf("%s connection from %s forbidden: AllowedEncryptionPublicKeys does not contain key %s", diff --git a/src/yggdrasil/tcp.go b/src/yggdrasil/tcp.go index 9cca419..a1b6402 100644 --- a/src/yggdrasil/tcp.go +++ b/src/yggdrasil/tcp.go @@ -57,6 +57,12 @@ type TcpUpgrade struct { name string } +type tcpOptions struct { + linkOptions + upgrade *TcpUpgrade + socksProxyAddr string +} + func (l *TcpListener) Stop() { defer func() { recover() }() close(l.stop) @@ -221,7 +227,10 @@ func (t *tcp) listener(l *TcpListener, listenaddr string) { return } t.waitgroup.Add(1) - go t.handler(sock, true, nil, l.upgrade) + options := tcpOptions{ + upgrade: l.upgrade, + } + go t.handler(sock, true, options) } } @@ -239,12 +248,12 @@ func (t *tcp) startCalling(saddr string) bool { // If the dial is successful, it launches the handler. // When finished, it removes the outgoing call, so reconnection attempts can be made later. // This all happens in a separate goroutine that it spawns. -func (t *tcp) call(saddr string, options interface{}, sintf string, upgrade *TcpUpgrade) { +func (t *tcp) call(saddr string, options tcpOptions, sintf string) { go func() { callname := saddr callproto := "TCP" - if upgrade != nil { - callproto = strings.ToUpper(upgrade.name) + if options.upgrade != nil { + callproto = strings.ToUpper(options.upgrade.name) } if sintf != "" { callname = fmt.Sprintf("%s/%s/%s", callproto, saddr, sintf) @@ -263,12 +272,11 @@ func (t *tcp) call(saddr string, options interface{}, sintf string, upgrade *Tcp }() var conn net.Conn var err error - socksaddr, issocks := options.(string) - if issocks { + if options.socksProxyAddr != "" { if sintf != "" { return } - dialerdst, er := net.ResolveTCPAddr("tcp", socksaddr) + dialerdst, er := net.ResolveTCPAddr("tcp", options.socksProxyAddr) if er != nil { return } @@ -282,7 +290,7 @@ func (t *tcp) call(saddr string, options interface{}, sintf string, upgrade *Tcp return } t.waitgroup.Add(1) - t.handler(conn, false, saddr, nil) + t.handler(conn, false, options) } else { dst, err := net.ResolveTCPAddr("tcp", saddr) if err != nil { @@ -348,19 +356,19 @@ func (t *tcp) call(saddr string, options interface{}, sintf string, upgrade *Tcp return } t.waitgroup.Add(1) - t.handler(conn, false, nil, upgrade) + t.handler(conn, false, options) } }() } -func (t *tcp) handler(sock net.Conn, incoming bool, options interface{}, upgrade *TcpUpgrade) { +func (t *tcp) handler(sock net.Conn, incoming bool, options tcpOptions) { defer t.waitgroup.Done() // Happens after sock.close defer sock.Close() t.setExtraOptions(sock) var upgraded bool - if upgrade != nil { + if options.upgrade != nil { var err error - if sock, err = upgrade.upgrade(sock); err != nil { + if sock, err = options.upgrade.upgrade(sock); err != nil { t.link.core.log.Errorln("TCP handler upgrade failed:", err) return } else { @@ -370,14 +378,14 @@ func (t *tcp) handler(sock net.Conn, incoming bool, options interface{}, upgrade stream := stream{} stream.init(sock) var name, proto, local, remote string - if socksaddr, issocks := options.(string); issocks { - name = "socks://" + sock.RemoteAddr().String() + "/" + socksaddr + if options.socksProxyAddr != "" { + name = "socks://" + sock.RemoteAddr().String() + "/" + options.socksProxyAddr proto = "socks" local, _, _ = net.SplitHostPort(sock.LocalAddr().String()) - remote, _, _ = net.SplitHostPort(socksaddr) + remote, _, _ = net.SplitHostPort(options.socksProxyAddr) } else { if upgraded { - proto = upgrade.name + proto = options.upgrade.name name = proto + "://" + sock.RemoteAddr().String() } else { proto = "tcp" @@ -387,7 +395,7 @@ func (t *tcp) handler(sock net.Conn, incoming bool, options interface{}, upgrade remote, _, _ = net.SplitHostPort(sock.RemoteAddr().String()) } force := net.ParseIP(strings.Split(remote, "%")[0]).IsLinkLocalUnicast() - link, err := t.link.core.link.create(&stream, name, proto, local, remote, incoming, force) + link, err := t.link.core.link.create(&stream, name, proto, local, remote, incoming, force, options.linkOptions) if err != nil { t.link.core.log.Println(err) panic(err)