diff --git a/external/github.com/gorilla/websocket/conn.go b/external/github.com/gorilla/websocket/conn.go index 55744a3ef..25a14581f 100644 --- a/external/github.com/gorilla/websocket/conn.go +++ b/external/github.com/gorilla/websocket/conn.go @@ -260,10 +260,12 @@ type Conn struct { newCompressionWriter func(io.WriteCloser, int) io.WriteCloser // Read fields - reader io.ReadCloser // the current reader returned to the application - readErr error - br *bufio.Reader - readRemaining int64 // bytes remaining in current frame. + reader io.ReadCloser // the current reader returned to the application + readErr error + br *bufio.Reader + // bytes remaining in current frame. + // set setReadRemaining to safely update this value and prevent overflow + readRemaining int64 readFinal bool // true the current message has more frames. readLength int64 // Message size. readLimit int64 // Maximum message size. @@ -320,6 +322,17 @@ func newConn(conn net.Conn, isServer bool, readBufferSize, writeBufferSize int, return c } +// setReadRemaining tracks the number of bytes remaining on the connection. If n +// overflows, an ErrReadLimit is returned. +func (c *Conn) setReadRemaining(n int64) error { + if n < 0 { + return ErrReadLimit + } + + c.readRemaining = n + return nil +} + // Subprotocol returns the negotiated protocol for the connection. func (c *Conn) Subprotocol() string { return c.subprotocol @@ -770,7 +783,7 @@ func (c *Conn) advanceFrame() (int, error) { final := p[0]&finalBit != 0 frameType := int(p[0] & 0xf) mask := p[1]&maskBit != 0 - c.readRemaining = int64(p[1] & 0x7f) + c.setReadRemaining(int64(p[1] & 0x7f)) c.readDecompress = false if c.newDecompressionReader != nil && (p[0]&rsv1Bit) != 0 { @@ -804,7 +817,17 @@ func (c *Conn) advanceFrame() (int, error) { return noFrame, c.handleProtocolError("unknown opcode " + strconv.Itoa(frameType)) } - // 3. Read and parse frame length. + // 3. Read and parse frame length as per + // https://tools.ietf.org/html/rfc6455#section-5.2 + // + // The length of the "Payload data", in bytes: if 0-125, that is the payload + // length. + // - If 126, the following 2 bytes interpreted as a 16-bit unsigned + // integer are the payload length. + // - If 127, the following 8 bytes interpreted as + // a 64-bit unsigned integer (the most significant bit MUST be 0) are the + // payload length. Multibyte length quantities are expressed in network byte + // order. switch c.readRemaining { case 126: @@ -812,13 +835,19 @@ func (c *Conn) advanceFrame() (int, error) { if err != nil { return noFrame, err } - c.readRemaining = int64(binary.BigEndian.Uint16(p)) + + if err := c.setReadRemaining(int64(binary.BigEndian.Uint16(p))); err != nil { + return noFrame, err + } case 127: p, err := c.read(8) if err != nil { return noFrame, err } - c.readRemaining = int64(binary.BigEndian.Uint64(p)) + + if err := c.setReadRemaining(int64(binary.BigEndian.Uint64(p))); err != nil { + return noFrame, err + } } // 4. Handle frame masking. @@ -841,6 +870,12 @@ func (c *Conn) advanceFrame() (int, error) { if frameType == continuationFrame || frameType == TextMessage || frameType == BinaryMessage { c.readLength += c.readRemaining + // Don't allow readLength to overflow in the presence of a large readRemaining + // counter. + if c.readLength < 0 { + return noFrame, ErrReadLimit + } + if c.readLimit > 0 && c.readLength > c.readLimit { c.WriteControl(CloseMessage, FormatCloseMessage(CloseMessageTooBig, ""), time.Now().Add(writeWait)) return noFrame, ErrReadLimit @@ -854,7 +889,7 @@ func (c *Conn) advanceFrame() (int, error) { var payload []byte if c.readRemaining > 0 { payload, err = c.read(int(c.readRemaining)) - c.readRemaining = 0 + c.setReadRemaining(0) if err != nil { return noFrame, err } @@ -927,6 +962,7 @@ func (c *Conn) NextReader() (messageType int, r io.Reader, err error) { c.readErr = hideTempErr(err) break } + if frameType == TextMessage || frameType == BinaryMessage { c.messageReader = &messageReader{c} c.reader = c.messageReader @@ -967,7 +1003,9 @@ func (r *messageReader) Read(b []byte) (int, error) { if c.isServer { c.readMaskPos = maskBytes(c.readMaskKey, c.readMaskPos, b[:n]) } - c.readRemaining -= int64(n) + rem := c.readRemaining + rem -= int64(n) + c.setReadRemaining(rem) if c.readRemaining > 0 && c.readErr == io.EOF { c.readErr = errUnexpectedEOF }