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ergo/irc/gateways.go
Shivaram Lingamneni 3480f124cd fix #688
2019-12-17 19:37:33 -05:00

156 lines
4.3 KiB
Go

// Copyright (c) 2012-2014 Jeremy Latt
// Copyright (c) 2014-2015 Edmund Huber
// Copyright (c) 2017 Daniel Oaks <daniel@danieloaks.net>
// released under the MIT license
package irc
import (
"errors"
"fmt"
"net"
"strings"
"time"
"github.com/oragono/oragono/irc/modes"
"github.com/oragono/oragono/irc/utils"
)
var (
errBadGatewayAddress = errors.New("PROXY/WEBIRC commands are not accepted from this IP address")
errBadProxyLine = errors.New("Invalid PROXY/WEBIRC command")
)
const (
// https://www.haproxy.org/download/1.8/doc/proxy-protocol.txt
// "a 108-byte buffer is always enough to store all the line and a trailing zero
// for string processing."
maxProxyLineLen = 107
)
type webircConfig struct {
PasswordString string `yaml:"password"`
Password []byte `yaml:"password-bytes"`
Fingerprint string
Hosts []string
allowedNets []net.IPNet
}
// Populate fills out our password or fingerprint.
func (wc *webircConfig) Populate() (err error) {
if wc.Fingerprint == "" && wc.PasswordString == "" {
return ErrNoFingerprintOrPassword
}
if wc.PasswordString != "" {
wc.Password, err = decodeLegacyPasswordHash(wc.PasswordString)
}
if err == nil {
wc.allowedNets, err = utils.ParseNetList(wc.Hosts)
}
return err
}
// ApplyProxiedIP applies the given IP to the client.
func (client *Client) ApplyProxiedIP(session *Session, proxiedIP string, tls bool) (err error, quitMsg string) {
// PROXY and WEBIRC are never accepted from a Tor listener, even if the address itself
// is whitelisted:
if client.isTor {
return errBadProxyLine, ""
}
// ensure IP is sane
parsedProxiedIP := net.ParseIP(proxiedIP).To16()
if parsedProxiedIP == nil {
return errBadProxyLine, fmt.Sprintf(client.t("Proxied IP address is not valid: [%s]"), proxiedIP)
}
isBanned, banMsg := client.server.checkBans(parsedProxiedIP)
if isBanned {
return errBanned, banMsg
}
// successfully added a limiter entry for the proxied IP;
// remove the entry for the real IP if applicable (#197)
client.server.connectionLimiter.RemoveClient(session.realIP)
// given IP is sane! override the client's current IP
client.server.logger.Info("localconnect-ip", "Accepted proxy IP for client", parsedProxiedIP.String())
client.stateMutex.Lock()
defer client.stateMutex.Unlock()
client.proxiedIP = parsedProxiedIP
session.proxiedIP = parsedProxiedIP
// nickmask will be updated when the client completes registration
// set tls info
client.certfp = ""
client.SetMode(modes.TLS, tls)
return nil, ""
}
// handle the PROXY command: http://www.haproxy.org/download/1.8/doc/proxy-protocol.txt
// PROXY must be sent as the first message in the session and has the syntax:
// PROXY TCP[46] SOURCEIP DESTIP SOURCEPORT DESTPORT\r\n
// unfortunately, an ipv6 SOURCEIP can start with a double colon; in this case,
// the message is invalid IRC and can't be parsed normally, hence the special handling.
func handleProxyCommand(server *Server, client *Client, session *Session, line string) (err error) {
var quitMsg string
defer func() {
if err != nil {
if quitMsg == "" {
quitMsg = client.t("Bad or unauthorized PROXY command")
}
client.Quit(quitMsg, session)
}
}()
params := strings.Fields(line)
if len(params) != 6 {
return errBadProxyLine
}
if utils.IPInNets(client.realIP, server.Config().Server.proxyAllowedFromNets) {
// assume PROXY connections are always secure
err, quitMsg = client.ApplyProxiedIP(session, params[2], true)
return
} else {
// real source IP is not authorized to issue PROXY:
return errBadGatewayAddress
}
}
// read a PROXY line one byte at a time, to ensure we don't read anything beyond
// that into a buffer, which would break the TLS handshake
func readRawProxyLine(conn net.Conn) (result string) {
// normally this is covered by ping timeouts, but we're doing this outside
// of the normal client goroutine:
conn.SetDeadline(time.Now().Add(time.Minute))
defer conn.SetDeadline(time.Time{})
var buf [maxProxyLineLen]byte
oneByte := make([]byte, 1)
i := 0
for i < maxProxyLineLen {
n, err := conn.Read(oneByte)
if err != nil {
return
} else if n == 1 {
buf[i] = oneByte[0]
if buf[i] == '\n' {
candidate := string(buf[0 : i+1])
if strings.HasPrefix(candidate, "PROXY") {
return candidate
} else {
return
}
}
i += 1
}
}
// no \r\n, fail out
return
}