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9589d019cb
I assumed gorilla validated UTF8 for incoming text messages. In fact, the documentation states: >It is the application's responsibility to ensure that text messages >are valid UTF-8 encoded text. and this applies to both incoming and outgoing messages. Consequently, even when enforce-utf8 is enabled, it was possible to send invalid UTF8 to Ergo inside a websocket text frame. This data would be incorrectly considered valid UTF8, and could be relayed to other clients, including to websocket clients inside a text frame. The resulting frame would violate the websocket protocol, causing web clients to be disconnected.
147 lines
3.4 KiB
Go
147 lines
3.4 KiB
Go
// Copyright (c) 2020 Shivaram Lingamneni
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// released under the MIT license
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package irc
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import (
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"bytes"
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"net"
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"unicode/utf8"
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"github.com/ergochat/irc-go/ircmsg"
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"github.com/ergochat/irc-go/ircreader"
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"github.com/gorilla/websocket"
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"github.com/ergochat/ergo/irc/utils"
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)
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const (
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initialBufferSize = 1024
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)
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var (
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crlf = []byte{'\r', '\n'}
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)
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// maximum total length, in bytes, of a single IRC message:
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func maxReadQBytes() int {
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return ircmsg.MaxlenTagsFromClient + MaxLineLen + 1024
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}
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// IRCConn abstracts away the distinction between a regular
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// net.Conn (which includes both raw TCP and TLS) and a websocket.
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// it doesn't expose the net.Conn, io.Reader, or io.Writer interfaces
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// because websockets are message-oriented, not stream-oriented, and
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// therefore this abstraction is message-oriented as well.
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type IRCConn interface {
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UnderlyingConn() *utils.WrappedConn
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// these take an IRC line or lines, correctly terminated with CRLF:
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WriteLine([]byte) error
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WriteLines([][]byte) error
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// this returns an IRC line, possibly terminated with CRLF, LF, or nothing:
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ReadLine() (line []byte, err error)
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Close() error
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}
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// IRCStreamConn is an IRCConn over a regular stream connection.
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type IRCStreamConn struct {
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conn *utils.WrappedConn
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reader ircreader.Reader
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}
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func NewIRCStreamConn(conn *utils.WrappedConn) *IRCStreamConn {
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var c IRCStreamConn
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c.conn = conn
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c.reader.Initialize(conn.Conn, initialBufferSize, maxReadQBytes())
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return &c
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}
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func (cc *IRCStreamConn) UnderlyingConn() *utils.WrappedConn {
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return cc.conn
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}
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func (cc *IRCStreamConn) WriteLine(buf []byte) (err error) {
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_, err = cc.conn.Write(buf)
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return
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}
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func (cc *IRCStreamConn) WriteLines(buffers [][]byte) (err error) {
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// on Linux, with a plaintext TCP or Unix domain socket,
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// the Go runtime will optimize this into a single writev(2) call:
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_, err = (*net.Buffers)(&buffers).WriteTo(cc.conn)
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return
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}
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func (cc *IRCStreamConn) ReadLine() ([]byte, error) {
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line, err := cc.reader.ReadLine()
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if err != nil {
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return nil, err
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} else if globalUtf8EnforcementSetting && !utf8.Valid(line) {
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return line, errInvalidUtf8
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} else {
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return line, nil
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}
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}
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func (cc *IRCStreamConn) Close() (err error) {
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return cc.conn.Close()
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}
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// IRCWSConn is an IRCConn over a websocket.
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type IRCWSConn struct {
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conn *websocket.Conn
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binary bool
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}
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func NewIRCWSConn(conn *websocket.Conn) IRCWSConn {
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binary := conn.Subprotocol() == "binary.ircv3.net"
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return IRCWSConn{conn: conn, binary: binary}
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}
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func (wc IRCWSConn) UnderlyingConn() *utils.WrappedConn {
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// just assume that the type is OK
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wConn, _ := wc.conn.UnderlyingConn().(*utils.WrappedConn)
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return wConn
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}
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func (wc IRCWSConn) WriteLine(buf []byte) (err error) {
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buf = bytes.TrimSuffix(buf, crlf)
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// #1483: if we have websockets at all, then we're enforcing utf8
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messageType := websocket.TextMessage
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if wc.binary {
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messageType = websocket.BinaryMessage
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}
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return wc.conn.WriteMessage(messageType, buf)
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}
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func (wc IRCWSConn) WriteLines(buffers [][]byte) (err error) {
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for _, buf := range buffers {
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err = wc.WriteLine(buf)
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if err != nil {
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return
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}
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}
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return
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}
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func (wc IRCWSConn) ReadLine() (line []byte, err error) {
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_, line, err = wc.conn.ReadMessage()
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if err == nil {
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if !utf8.Valid(line) {
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return line, errInvalidUtf8
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}
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return line, nil
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} else if err == websocket.ErrReadLimit {
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return line, ircreader.ErrReadQ
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} else {
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return line, err
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}
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}
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func (wc IRCWSConn) Close() (err error) {
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return wc.conn.Close()
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}
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