506 lines
16 KiB
Go
506 lines
16 KiB
Go
// Copyright 2020 The Gitea Authors. All rights reserved.
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// SPDX-License-Identifier: MIT
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package proxyprotocol
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import (
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"bufio"
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"bytes"
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"encoding/binary"
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"io"
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"net"
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"strconv"
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"strings"
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"sync"
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"time"
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"code.gitea.io/gitea/modules/log"
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)
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var (
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// v1Prefix is the string we look for at the start of a connection
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// to check if this connection is using the proxy protocol
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v1Prefix = []byte("PROXY ")
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v1PrefixLen = len(v1Prefix)
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v2Prefix = []byte("\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A")
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v2PrefixLen = len(v2Prefix)
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)
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// Conn is used to wrap and underlying connection which is speaking the
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// Proxy Protocol. RemoteAddr() will return the address of the client
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// instead of the proxy address.
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type Conn struct {
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bufReader *bufio.Reader
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conn net.Conn
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localAddr net.Addr
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remoteAddr net.Addr
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once sync.Once
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proxyHeaderTimeout time.Duration
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acceptUnknown bool
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}
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// NewConn is used to wrap a net.Conn speaking the proxy protocol into
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// a proxyprotocol.Conn
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func NewConn(conn net.Conn, timeout time.Duration) *Conn {
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pConn := &Conn{
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bufReader: bufio.NewReader(conn),
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conn: conn,
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proxyHeaderTimeout: timeout,
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}
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return pConn
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}
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// Read reads data from the connection.
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// It will initially read the proxy protocol header.
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// If there is an error parsing the header, it is returned and the socket is closed.
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func (p *Conn) Read(b []byte) (int, error) {
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if err := p.readProxyHeaderOnce(); err != nil {
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return 0, err
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}
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return p.bufReader.Read(b)
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}
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// ReadFrom reads data from a provided reader and copies it to the connection.
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func (p *Conn) ReadFrom(r io.Reader) (int64, error) {
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if err := p.readProxyHeaderOnce(); err != nil {
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return 0, err
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}
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if rf, ok := p.conn.(io.ReaderFrom); ok {
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return rf.ReadFrom(r)
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}
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return io.Copy(p.conn, r)
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}
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// WriteTo reads data from the connection and writes it to the writer.
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// It will initially read the proxy protocol header.
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// If there is an error parsing the header, it is returned and the socket is closed.
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func (p *Conn) WriteTo(w io.Writer) (int64, error) {
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if err := p.readProxyHeaderOnce(); err != nil {
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return 0, err
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}
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return p.bufReader.WriteTo(w)
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}
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// Write writes data to the connection.
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// Write can be made to time out and return an error after a fixed
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// time limit; see SetDeadline and SetWriteDeadline.
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func (p *Conn) Write(b []byte) (int, error) {
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if err := p.readProxyHeaderOnce(); err != nil {
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return 0, err
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}
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return p.conn.Write(b)
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}
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// Close closes the connection.
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// Any blocked Read or Write operations will be unblocked and return errors.
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func (p *Conn) Close() error {
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return p.conn.Close()
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}
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// LocalAddr returns the local network address.
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func (p *Conn) LocalAddr() net.Addr {
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_ = p.readProxyHeaderOnce()
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if p.localAddr != nil {
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return p.localAddr
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}
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return p.conn.LocalAddr()
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}
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// RemoteAddr returns the address of the client if the proxy
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// protocol is being used, otherwise just returns the address of
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// the socket peer. If there is an error parsing the header, the
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// address of the client is not returned, and the socket is closed.
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// One implication of this is that the call could block if the
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// client is slow. Using a Deadline is recommended if this is called
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// before Read()
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func (p *Conn) RemoteAddr() net.Addr {
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_ = p.readProxyHeaderOnce()
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if p.remoteAddr != nil {
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return p.remoteAddr
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}
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return p.conn.RemoteAddr()
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}
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// SetDeadline sets the read and write deadlines associated
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// with the connection. It is equivalent to calling both
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// SetReadDeadline and SetWriteDeadline.
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//
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// A deadline is an absolute time after which I/O operations
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// fail instead of blocking. The deadline applies to all future
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// and pending I/O, not just the immediately following call to
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// Read or Write. After a deadline has been exceeded, the
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// connection can be refreshed by setting a deadline in the future.
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//
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// If the deadline is exceeded a call to Read or Write or to other
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// I/O methods will return an error that wraps os.ErrDeadlineExceeded.
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// This can be tested using errors.Is(err, os.ErrDeadlineExceeded).
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// The error's Timeout method will return true, but note that there
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// are other possible errors for which the Timeout method will
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// return true even if the deadline has not been exceeded.
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//
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// An idle timeout can be implemented by repeatedly extending
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// the deadline after successful Read or Write calls.
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//
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// A zero value for t means I/O operations will not time out.
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func (p *Conn) SetDeadline(t time.Time) error {
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return p.conn.SetDeadline(t)
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}
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// SetReadDeadline sets the deadline for future Read calls
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// and any currently-blocked Read call.
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// A zero value for t means Read will not time out.
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func (p *Conn) SetReadDeadline(t time.Time) error {
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return p.conn.SetReadDeadline(t)
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}
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// SetWriteDeadline sets the deadline for future Write calls
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// and any currently-blocked Write call.
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// Even if write times out, it may return n > 0, indicating that
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// some of the data was successfully written.
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// A zero value for t means Write will not time out.
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func (p *Conn) SetWriteDeadline(t time.Time) error {
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return p.conn.SetWriteDeadline(t)
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}
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// readProxyHeaderOnce will ensure that the proxy header has been read
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func (p *Conn) readProxyHeaderOnce() (err error) {
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p.once.Do(func() {
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if err = p.readProxyHeader(); err != nil && err != io.EOF {
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log.Error("Failed to read proxy prefix: %v", err)
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p.Close()
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p.bufReader = bufio.NewReader(p.conn)
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}
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})
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return err
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}
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func (p *Conn) readProxyHeader() error {
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if p.proxyHeaderTimeout != 0 {
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readDeadLine := time.Now().Add(p.proxyHeaderTimeout)
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_ = p.conn.SetReadDeadline(readDeadLine)
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defer func() {
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_ = p.conn.SetReadDeadline(time.Time{})
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}()
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}
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inp, err := p.bufReader.Peek(v1PrefixLen)
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if err != nil {
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return err
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}
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if bytes.Equal(inp, v1Prefix) {
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return p.readV1ProxyHeader()
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}
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inp, err = p.bufReader.Peek(v2PrefixLen)
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if err != nil {
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return err
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}
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if bytes.Equal(inp, v2Prefix) {
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return p.readV2ProxyHeader()
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}
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return &ErrBadHeader{inp}
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}
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func (p *Conn) readV2ProxyHeader() error {
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// The binary header format starts with a constant 12 bytes block containing the
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// protocol signature :
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//
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// \x0D \x0A \x0D \x0A \x00 \x0D \x0A \x51 \x55 \x49 \x54 \x0A
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//
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// Note that this block contains a null byte at the 5th position, so it must not
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// be handled as a null-terminated string.
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if _, err := p.bufReader.Discard(v2PrefixLen); err != nil {
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// This shouldn't happen as we have already asserted that there should be enough in the buffer
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return err
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}
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// The next byte (the 13th one) is the protocol version and command.
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version, err := p.bufReader.ReadByte()
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if err != nil {
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return err
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}
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// The 14th byte contains the transport protocol and address family.otocol.
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familyByte, err := p.bufReader.ReadByte()
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if err != nil {
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return err
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}
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// The 15th and 16th bytes is the address length in bytes in network endian order.
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var addressLen uint16
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if err := binary.Read(p.bufReader, binary.BigEndian, &addressLen); err != nil {
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return err
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}
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// Now handle the version byte: (14th byte).
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// The highest four bits contains the version. As of this specification, it must
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// always be sent as \x2 and the receiver must only accept this value.
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if version>>4 != 0x2 {
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return &ErrBadHeader{append(v2Prefix, version, familyByte, uint8(addressLen>>8), uint8(addressLen&0xff))}
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}
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// The lowest four bits represents the command :
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switch version & 0xf {
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case 0x0:
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// - \x0 : LOCAL : the connection was established on purpose by the proxy
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// without being relayed. The connection endpoints are the sender and the
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// receiver. Such connections exist when the proxy sends health-checks to the
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// server. The receiver must accept this connection as valid and must use the
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// real connection endpoints and discard the protocol block including the
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// family which is ignored.
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// We therefore ignore the 14th, 15th and 16th bytes
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p.remoteAddr = p.conn.LocalAddr()
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p.localAddr = p.conn.RemoteAddr()
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return nil
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case 0x1:
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// - \x1 : PROXY : the connection was established on behalf of another node,
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// and reflects the original connection endpoints. The receiver must then use
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// the information provided in the protocol block to get original the address.
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default:
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// - other values are unassigned and must not be emitted by senders. Receivers
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// must drop connections presenting unexpected values here.
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return &ErrBadHeader{append(v2Prefix, version, familyByte, uint8(addressLen>>8), uint8(addressLen&0xff))}
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}
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// Now handle the familyByte byte: (15th byte).
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// The highest 4 bits contain the address family, the lowest 4 bits contain the protocol
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// The address family maps to the original socket family without necessarily
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// matching the values internally used by the system. It may be one of :
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//
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// - 0x0 : AF_UNSPEC : the connection is forwarded for an unknown, unspecified
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// or unsupported protocol. The sender should use this family when sending
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// LOCAL commands or when dealing with unsupported protocol families. The
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// receiver is free to accept the connection anyway and use the real endpoint
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// addresses or to reject it. The receiver should ignore address information.
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//
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// - 0x1 : AF_INET : the forwarded connection uses the AF_INET address family
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// (IPv4). The addresses are exactly 4 bytes each in network byte order,
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// followed by transport protocol information (typically ports).
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//
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// - 0x2 : AF_INET6 : the forwarded connection uses the AF_INET6 address family
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// (IPv6). The addresses are exactly 16 bytes each in network byte order,
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// followed by transport protocol information (typically ports).
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//
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// - 0x3 : AF_UNIX : the forwarded connection uses the AF_UNIX address family
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// (UNIX). The addresses are exactly 108 bytes each.
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//
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// - other values are unspecified and must not be emitted in version 2 of this
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// protocol and must be rejected as invalid by receivers.
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// The transport protocol is specified in the lowest 4 bits of the 14th byte :
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//
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// - 0x0 : UNSPEC : the connection is forwarded for an unknown, unspecified
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// or unsupported protocol. The sender should use this family when sending
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// LOCAL commands or when dealing with unsupported protocol families. The
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// receiver is free to accept the connection anyway and use the real endpoint
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// addresses or to reject it. The receiver should ignore address information.
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//
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// - 0x1 : STREAM : the forwarded connection uses a SOCK_STREAM protocol (eg:
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// TCP or UNIX_STREAM). When used with AF_INET/AF_INET6 (TCP), the addresses
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// are followed by the source and destination ports represented on 2 bytes
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// each in network byte order.
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//
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// - 0x2 : DGRAM : the forwarded connection uses a SOCK_DGRAM protocol (eg:
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// UDP or UNIX_DGRAM). When used with AF_INET/AF_INET6 (UDP), the addresses
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// are followed by the source and destination ports represented on 2 bytes
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// each in network byte order.
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//
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// - other values are unspecified and must not be emitted in version 2 of this
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// protocol and must be rejected as invalid by receivers.
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if familyByte>>4 == 0x0 || familyByte&0xf == 0x0 {
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// - hi 0x0 : AF_UNSPEC : the connection is forwarded for an unknown address type
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// or
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// - lo 0x0 : UNSPEC : the connection is forwarded for an unspecified protocol
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if !p.acceptUnknown {
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p.conn.Close()
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return &ErrBadHeader{append(v2Prefix, version, familyByte, uint8(addressLen>>8), uint8(addressLen&0xff))}
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}
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p.remoteAddr = p.conn.LocalAddr()
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p.localAddr = p.conn.RemoteAddr()
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_, err = p.bufReader.Discard(int(addressLen))
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return err
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}
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// other address or protocol
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if (familyByte>>4) > 0x3 || (familyByte&0xf) > 0x2 {
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return &ErrBadHeader{append(v2Prefix, version, familyByte, uint8(addressLen>>8), uint8(addressLen&0xff))}
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}
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// Handle AF_UNIX addresses
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if familyByte>>4 == 0x3 {
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// - \x31 : UNIX stream : the forwarded connection uses SOCK_STREAM over the
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// AF_UNIX protocol family. Address length is 2*108 = 216 bytes.
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// - \x32 : UNIX datagram : the forwarded connection uses SOCK_DGRAM over the
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// AF_UNIX protocol family. Address length is 2*108 = 216 bytes.
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if addressLen != 216 {
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return &ErrBadHeader{append(v2Prefix, version, familyByte, uint8(addressLen>>8), uint8(addressLen&0xff))}
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}
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remoteName := make([]byte, 108)
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localName := make([]byte, 108)
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if _, err := p.bufReader.Read(remoteName); err != nil {
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return err
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}
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if _, err := p.bufReader.Read(localName); err != nil {
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return err
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}
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protocol := "unix"
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if familyByte&0xf == 2 {
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protocol = "unixgram"
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}
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p.remoteAddr = &net.UnixAddr{
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Name: string(remoteName),
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Net: protocol,
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}
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p.localAddr = &net.UnixAddr{
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Name: string(localName),
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Net: protocol,
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}
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return nil
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}
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var remoteIP []byte
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var localIP []byte
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var remotePort uint16
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var localPort uint16
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if familyByte>>4 == 0x1 {
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// AF_INET
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// - \x11 : TCP over IPv4 : the forwarded connection uses TCP over the AF_INET
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// protocol family. Address length is 2*4 + 2*2 = 12 bytes.
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// - \x12 : UDP over IPv4 : the forwarded connection uses UDP over the AF_INET
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// protocol family. Address length is 2*4 + 2*2 = 12 bytes.
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if addressLen != 12 {
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return &ErrBadHeader{append(v2Prefix, version, familyByte, uint8(addressLen>>8), uint8(addressLen&0xff))}
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}
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remoteIP = make([]byte, 4)
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localIP = make([]byte, 4)
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} else {
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// AF_INET6
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// - \x21 : TCP over IPv6 : the forwarded connection uses TCP over the AF_INET6
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// protocol family. Address length is 2*16 + 2*2 = 36 bytes.
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// - \x22 : UDP over IPv6 : the forwarded connection uses UDP over the AF_INET6
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// protocol family. Address length is 2*16 + 2*2 = 36 bytes.
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if addressLen != 36 {
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return &ErrBadHeader{append(v2Prefix, version, familyByte, uint8(addressLen>>8), uint8(addressLen&0xff))}
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}
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remoteIP = make([]byte, 16)
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localIP = make([]byte, 16)
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}
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if _, err := p.bufReader.Read(remoteIP); err != nil {
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return err
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}
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if _, err := p.bufReader.Read(localIP); err != nil {
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return err
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}
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if err := binary.Read(p.bufReader, binary.BigEndian, &remotePort); err != nil {
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return err
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}
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if err := binary.Read(p.bufReader, binary.BigEndian, &localPort); err != nil {
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return err
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}
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if familyByte&0xf == 1 {
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p.remoteAddr = &net.TCPAddr{
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IP: remoteIP,
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Port: int(remotePort),
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}
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p.localAddr = &net.TCPAddr{
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IP: localIP,
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Port: int(localPort),
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}
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} else {
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p.remoteAddr = &net.UDPAddr{
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IP: remoteIP,
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Port: int(remotePort),
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}
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p.localAddr = &net.UDPAddr{
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IP: localIP,
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Port: int(localPort),
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}
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}
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return nil
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}
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func (p *Conn) readV1ProxyHeader() error {
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// Read until a newline
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header, err := p.bufReader.ReadString('\n')
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if err != nil {
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p.conn.Close()
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return err
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}
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if header[len(header)-2] != '\r' {
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return &ErrBadHeader{[]byte(header)}
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}
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// Strip the carriage return and new line
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header = header[:len(header)-2]
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// Split on spaces, should be (PROXY <type> <remote addr> <local addr> <remote port> <local port>)
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parts := strings.Split(header, " ")
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if len(parts) < 2 {
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p.conn.Close()
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return &ErrBadHeader{[]byte(header)}
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}
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// Verify the type is known
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switch parts[1] {
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case "UNKNOWN":
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if !p.acceptUnknown || len(parts) != 2 {
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p.conn.Close()
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return &ErrBadHeader{[]byte(header)}
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}
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p.remoteAddr = p.conn.LocalAddr()
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p.localAddr = p.conn.RemoteAddr()
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return nil
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case "TCP4":
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case "TCP6":
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default:
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p.conn.Close()
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return &ErrBadAddressType{parts[1]}
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}
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if len(parts) != 6 {
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p.conn.Close()
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return &ErrBadHeader{[]byte(header)}
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}
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// Parse out the remote address
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ip := net.ParseIP(parts[2])
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if ip == nil {
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p.conn.Close()
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return &ErrBadRemote{parts[2], parts[4]}
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}
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port, err := strconv.Atoi(parts[4])
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if err != nil {
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p.conn.Close()
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return &ErrBadRemote{parts[2], parts[4]}
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}
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p.remoteAddr = &net.TCPAddr{IP: ip, Port: port}
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// Parse out the destination address
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ip = net.ParseIP(parts[3])
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if ip == nil {
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p.conn.Close()
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return &ErrBadLocal{parts[3], parts[5]}
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}
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port, err = strconv.Atoi(parts[5])
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|
if err != nil {
|
|
p.conn.Close()
|
|
return &ErrBadLocal{parts[3], parts[5]}
|
|
}
|
|
p.localAddr = &net.TCPAddr{IP: ip, Port: port}
|
|
|
|
return nil
|
|
}
|