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-rw-r--r--modules/proxyprotocol/conn.go505
1 files changed, 505 insertions, 0 deletions
diff --git a/modules/proxyprotocol/conn.go b/modules/proxyprotocol/conn.go
new file mode 100644
index 0000000..f437f13
--- /dev/null
+++ b/modules/proxyprotocol/conn.go
@@ -0,0 +1,505 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package proxyprotocol
+
+import (
+ "bufio"
+ "bytes"
+ "encoding/binary"
+ "io"
+ "net"
+ "strconv"
+ "strings"
+ "sync"
+ "time"
+
+ "code.gitea.io/gitea/modules/log"
+)
+
+var (
+ // v1Prefix is the string we look for at the start of a connection
+ // to check if this connection is using the proxy protocol
+ v1Prefix = []byte("PROXY ")
+ v1PrefixLen = len(v1Prefix)
+ v2Prefix = []byte("\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A")
+ v2PrefixLen = len(v2Prefix)
+)
+
+// Conn is used to wrap and underlying connection which is speaking the
+// Proxy Protocol. RemoteAddr() will return the address of the client
+// instead of the proxy address.
+type Conn struct {
+ bufReader *bufio.Reader
+ conn net.Conn
+ localAddr net.Addr
+ remoteAddr net.Addr
+ once sync.Once
+ proxyHeaderTimeout time.Duration
+ acceptUnknown bool
+}
+
+// NewConn is used to wrap a net.Conn speaking the proxy protocol into
+// a proxyprotocol.Conn
+func NewConn(conn net.Conn, timeout time.Duration) *Conn {
+ pConn := &Conn{
+ bufReader: bufio.NewReader(conn),
+ conn: conn,
+ proxyHeaderTimeout: timeout,
+ }
+ return pConn
+}
+
+// Read reads data from the connection.
+// It will initially read the proxy protocol header.
+// If there is an error parsing the header, it is returned and the socket is closed.
+func (p *Conn) Read(b []byte) (int, error) {
+ if err := p.readProxyHeaderOnce(); err != nil {
+ return 0, err
+ }
+ return p.bufReader.Read(b)
+}
+
+// ReadFrom reads data from a provided reader and copies it to the connection.
+func (p *Conn) ReadFrom(r io.Reader) (int64, error) {
+ if err := p.readProxyHeaderOnce(); err != nil {
+ return 0, err
+ }
+ if rf, ok := p.conn.(io.ReaderFrom); ok {
+ return rf.ReadFrom(r)
+ }
+ return io.Copy(p.conn, r)
+}
+
+// WriteTo reads data from the connection and writes it to the writer.
+// It will initially read the proxy protocol header.
+// If there is an error parsing the header, it is returned and the socket is closed.
+func (p *Conn) WriteTo(w io.Writer) (int64, error) {
+ if err := p.readProxyHeaderOnce(); err != nil {
+ return 0, err
+ }
+ return p.bufReader.WriteTo(w)
+}
+
+// Write writes data to the connection.
+// Write can be made to time out and return an error after a fixed
+// time limit; see SetDeadline and SetWriteDeadline.
+func (p *Conn) Write(b []byte) (int, error) {
+ if err := p.readProxyHeaderOnce(); err != nil {
+ return 0, err
+ }
+ return p.conn.Write(b)
+}
+
+// Close closes the connection.
+// Any blocked Read or Write operations will be unblocked and return errors.
+func (p *Conn) Close() error {
+ return p.conn.Close()
+}
+
+// LocalAddr returns the local network address.
+func (p *Conn) LocalAddr() net.Addr {
+ _ = p.readProxyHeaderOnce()
+ if p.localAddr != nil {
+ return p.localAddr
+ }
+ return p.conn.LocalAddr()
+}
+
+// RemoteAddr returns the address of the client if the proxy
+// protocol is being used, otherwise just returns the address of
+// the socket peer. If there is an error parsing the header, the
+// address of the client is not returned, and the socket is closed.
+// One implication of this is that the call could block if the
+// client is slow. Using a Deadline is recommended if this is called
+// before Read()
+func (p *Conn) RemoteAddr() net.Addr {
+ _ = p.readProxyHeaderOnce()
+ if p.remoteAddr != nil {
+ return p.remoteAddr
+ }
+ return p.conn.RemoteAddr()
+}
+
+// SetDeadline sets the read and write deadlines associated
+// with the connection. It is equivalent to calling both
+// SetReadDeadline and SetWriteDeadline.
+//
+// A deadline is an absolute time after which I/O operations
+// fail instead of blocking. The deadline applies to all future
+// and pending I/O, not just the immediately following call to
+// Read or Write. After a deadline has been exceeded, the
+// connection can be refreshed by setting a deadline in the future.
+//
+// If the deadline is exceeded a call to Read or Write or to other
+// I/O methods will return an error that wraps os.ErrDeadlineExceeded.
+// This can be tested using errors.Is(err, os.ErrDeadlineExceeded).
+// The error's Timeout method will return true, but note that there
+// are other possible errors for which the Timeout method will
+// return true even if the deadline has not been exceeded.
+//
+// An idle timeout can be implemented by repeatedly extending
+// the deadline after successful Read or Write calls.
+//
+// A zero value for t means I/O operations will not time out.
+func (p *Conn) SetDeadline(t time.Time) error {
+ return p.conn.SetDeadline(t)
+}
+
+// SetReadDeadline sets the deadline for future Read calls
+// and any currently-blocked Read call.
+// A zero value for t means Read will not time out.
+func (p *Conn) SetReadDeadline(t time.Time) error {
+ return p.conn.SetReadDeadline(t)
+}
+
+// SetWriteDeadline sets the deadline for future Write calls
+// and any currently-blocked Write call.
+// Even if write times out, it may return n > 0, indicating that
+// some of the data was successfully written.
+// A zero value for t means Write will not time out.
+func (p *Conn) SetWriteDeadline(t time.Time) error {
+ return p.conn.SetWriteDeadline(t)
+}
+
+// readProxyHeaderOnce will ensure that the proxy header has been read
+func (p *Conn) readProxyHeaderOnce() (err error) {
+ p.once.Do(func() {
+ if err = p.readProxyHeader(); err != nil && err != io.EOF {
+ log.Error("Failed to read proxy prefix: %v", err)
+ p.Close()
+ p.bufReader = bufio.NewReader(p.conn)
+ }
+ })
+ return err
+}
+
+func (p *Conn) readProxyHeader() error {
+ if p.proxyHeaderTimeout != 0 {
+ readDeadLine := time.Now().Add(p.proxyHeaderTimeout)
+ _ = p.conn.SetReadDeadline(readDeadLine)
+ defer func() {
+ _ = p.conn.SetReadDeadline(time.Time{})
+ }()
+ }
+
+ inp, err := p.bufReader.Peek(v1PrefixLen)
+ if err != nil {
+ return err
+ }
+
+ if bytes.Equal(inp, v1Prefix) {
+ return p.readV1ProxyHeader()
+ }
+
+ inp, err = p.bufReader.Peek(v2PrefixLen)
+ if err != nil {
+ return err
+ }
+ if bytes.Equal(inp, v2Prefix) {
+ return p.readV2ProxyHeader()
+ }
+
+ return &ErrBadHeader{inp}
+}
+
+func (p *Conn) readV2ProxyHeader() error {
+ // The binary header format starts with a constant 12 bytes block containing the
+ // protocol signature :
+ //
+ // \x0D \x0A \x0D \x0A \x00 \x0D \x0A \x51 \x55 \x49 \x54 \x0A
+ //
+ // Note that this block contains a null byte at the 5th position, so it must not
+ // be handled as a null-terminated string.
+
+ if _, err := p.bufReader.Discard(v2PrefixLen); err != nil {
+ // This shouldn't happen as we have already asserted that there should be enough in the buffer
+ return err
+ }
+
+ // The next byte (the 13th one) is the protocol version and command.
+ version, err := p.bufReader.ReadByte()
+ if err != nil {
+ return err
+ }
+
+ // The 14th byte contains the transport protocol and address family.otocol.
+ familyByte, err := p.bufReader.ReadByte()
+ if err != nil {
+ return err
+ }
+
+ // The 15th and 16th bytes is the address length in bytes in network endian order.
+ var addressLen uint16
+ if err := binary.Read(p.bufReader, binary.BigEndian, &addressLen); err != nil {
+ return err
+ }
+
+ // Now handle the version byte: (14th byte).
+ // The highest four bits contains the version. As of this specification, it must
+ // always be sent as \x2 and the receiver must only accept this value.
+ if version>>4 != 0x2 {
+ return &ErrBadHeader{append(v2Prefix, version, familyByte, uint8(addressLen>>8), uint8(addressLen&0xff))}
+ }
+
+ // The lowest four bits represents the command :
+ switch version & 0xf {
+ case 0x0:
+ // - \x0 : LOCAL : the connection was established on purpose by the proxy
+ // without being relayed. The connection endpoints are the sender and the
+ // receiver. Such connections exist when the proxy sends health-checks to the
+ // server. The receiver must accept this connection as valid and must use the
+ // real connection endpoints and discard the protocol block including the
+ // family which is ignored.
+
+ // We therefore ignore the 14th, 15th and 16th bytes
+ p.remoteAddr = p.conn.LocalAddr()
+ p.localAddr = p.conn.RemoteAddr()
+ return nil
+ case 0x1:
+ // - \x1 : PROXY : the connection was established on behalf of another node,
+ // and reflects the original connection endpoints. The receiver must then use
+ // the information provided in the protocol block to get original the address.
+ default:
+ // - other values are unassigned and must not be emitted by senders. Receivers
+ // must drop connections presenting unexpected values here.
+ return &ErrBadHeader{append(v2Prefix, version, familyByte, uint8(addressLen>>8), uint8(addressLen&0xff))}
+ }
+
+ // Now handle the familyByte byte: (15th byte).
+ // The highest 4 bits contain the address family, the lowest 4 bits contain the protocol
+
+ // The address family maps to the original socket family without necessarily
+ // matching the values internally used by the system. It may be one of :
+ //
+ // - 0x0 : AF_UNSPEC : the connection is forwarded for an unknown, unspecified
+ // or unsupported protocol. The sender should use this family when sending
+ // LOCAL commands or when dealing with unsupported protocol families. The
+ // receiver is free to accept the connection anyway and use the real endpoint
+ // addresses or to reject it. The receiver should ignore address information.
+ //
+ // - 0x1 : AF_INET : the forwarded connection uses the AF_INET address family
+ // (IPv4). The addresses are exactly 4 bytes each in network byte order,
+ // followed by transport protocol information (typically ports).
+ //
+ // - 0x2 : AF_INET6 : the forwarded connection uses the AF_INET6 address family
+ // (IPv6). The addresses are exactly 16 bytes each in network byte order,
+ // followed by transport protocol information (typically ports).
+ //
+ // - 0x3 : AF_UNIX : the forwarded connection uses the AF_UNIX address family
+ // (UNIX). The addresses are exactly 108 bytes each.
+ //
+ // - other values are unspecified and must not be emitted in version 2 of this
+ // protocol and must be rejected as invalid by receivers.
+
+ // The transport protocol is specified in the lowest 4 bits of the 14th byte :
+ //
+ // - 0x0 : UNSPEC : the connection is forwarded for an unknown, unspecified
+ // or unsupported protocol. The sender should use this family when sending
+ // LOCAL commands or when dealing with unsupported protocol families. The
+ // receiver is free to accept the connection anyway and use the real endpoint
+ // addresses or to reject it. The receiver should ignore address information.
+ //
+ // - 0x1 : STREAM : the forwarded connection uses a SOCK_STREAM protocol (eg:
+ // TCP or UNIX_STREAM). When used with AF_INET/AF_INET6 (TCP), the addresses
+ // are followed by the source and destination ports represented on 2 bytes
+ // each in network byte order.
+ //
+ // - 0x2 : DGRAM : the forwarded connection uses a SOCK_DGRAM protocol (eg:
+ // UDP or UNIX_DGRAM). When used with AF_INET/AF_INET6 (UDP), the addresses
+ // are followed by the source and destination ports represented on 2 bytes
+ // each in network byte order.
+ //
+ // - other values are unspecified and must not be emitted in version 2 of this
+ // protocol and must be rejected as invalid by receivers.
+
+ if familyByte>>4 == 0x0 || familyByte&0xf == 0x0 {
+ // - hi 0x0 : AF_UNSPEC : the connection is forwarded for an unknown address type
+ // or
+ // - lo 0x0 : UNSPEC : the connection is forwarded for an unspecified protocol
+ if !p.acceptUnknown {
+ p.conn.Close()
+ return &ErrBadHeader{append(v2Prefix, version, familyByte, uint8(addressLen>>8), uint8(addressLen&0xff))}
+ }
+ p.remoteAddr = p.conn.LocalAddr()
+ p.localAddr = p.conn.RemoteAddr()
+ _, err = p.bufReader.Discard(int(addressLen))
+ return err
+ }
+
+ // other address or protocol
+ if (familyByte>>4) > 0x3 || (familyByte&0xf) > 0x2 {
+ return &ErrBadHeader{append(v2Prefix, version, familyByte, uint8(addressLen>>8), uint8(addressLen&0xff))}
+ }
+
+ // Handle AF_UNIX addresses
+ if familyByte>>4 == 0x3 {
+ // - \x31 : UNIX stream : the forwarded connection uses SOCK_STREAM over the
+ // AF_UNIX protocol family. Address length is 2*108 = 216 bytes.
+ // - \x32 : UNIX datagram : the forwarded connection uses SOCK_DGRAM over the
+ // AF_UNIX protocol family. Address length is 2*108 = 216 bytes.
+ if addressLen != 216 {
+ return &ErrBadHeader{append(v2Prefix, version, familyByte, uint8(addressLen>>8), uint8(addressLen&0xff))}
+ }
+ remoteName := make([]byte, 108)
+ localName := make([]byte, 108)
+ if _, err := p.bufReader.Read(remoteName); err != nil {
+ return err
+ }
+ if _, err := p.bufReader.Read(localName); err != nil {
+ return err
+ }
+ protocol := "unix"
+ if familyByte&0xf == 2 {
+ protocol = "unixgram"
+ }
+
+ p.remoteAddr = &net.UnixAddr{
+ Name: string(remoteName),
+ Net: protocol,
+ }
+ p.localAddr = &net.UnixAddr{
+ Name: string(localName),
+ Net: protocol,
+ }
+ return nil
+ }
+
+ var remoteIP []byte
+ var localIP []byte
+ var remotePort uint16
+ var localPort uint16
+
+ if familyByte>>4 == 0x1 {
+ // AF_INET
+ // - \x11 : TCP over IPv4 : the forwarded connection uses TCP over the AF_INET
+ // protocol family. Address length is 2*4 + 2*2 = 12 bytes.
+ // - \x12 : UDP over IPv4 : the forwarded connection uses UDP over the AF_INET
+ // protocol family. Address length is 2*4 + 2*2 = 12 bytes.
+ if addressLen != 12 {
+ return &ErrBadHeader{append(v2Prefix, version, familyByte, uint8(addressLen>>8), uint8(addressLen&0xff))}
+ }
+
+ remoteIP = make([]byte, 4)
+ localIP = make([]byte, 4)
+ } else {
+ // AF_INET6
+ // - \x21 : TCP over IPv6 : the forwarded connection uses TCP over the AF_INET6
+ // protocol family. Address length is 2*16 + 2*2 = 36 bytes.
+ // - \x22 : UDP over IPv6 : the forwarded connection uses UDP over the AF_INET6
+ // protocol family. Address length is 2*16 + 2*2 = 36 bytes.
+ if addressLen != 36 {
+ return &ErrBadHeader{append(v2Prefix, version, familyByte, uint8(addressLen>>8), uint8(addressLen&0xff))}
+ }
+
+ remoteIP = make([]byte, 16)
+ localIP = make([]byte, 16)
+ }
+
+ if _, err := p.bufReader.Read(remoteIP); err != nil {
+ return err
+ }
+ if _, err := p.bufReader.Read(localIP); err != nil {
+ return err
+ }
+ if err := binary.Read(p.bufReader, binary.BigEndian, &remotePort); err != nil {
+ return err
+ }
+ if err := binary.Read(p.bufReader, binary.BigEndian, &localPort); err != nil {
+ return err
+ }
+
+ if familyByte&0xf == 1 {
+ p.remoteAddr = &net.TCPAddr{
+ IP: remoteIP,
+ Port: int(remotePort),
+ }
+ p.localAddr = &net.TCPAddr{
+ IP: localIP,
+ Port: int(localPort),
+ }
+ } else {
+ p.remoteAddr = &net.UDPAddr{
+ IP: remoteIP,
+ Port: int(remotePort),
+ }
+ p.localAddr = &net.UDPAddr{
+ IP: localIP,
+ Port: int(localPort),
+ }
+ }
+ return nil
+}
+
+func (p *Conn) readV1ProxyHeader() error {
+ // Read until a newline
+ header, err := p.bufReader.ReadString('\n')
+ if err != nil {
+ p.conn.Close()
+ return err
+ }
+
+ if header[len(header)-2] != '\r' {
+ return &ErrBadHeader{[]byte(header)}
+ }
+
+ // Strip the carriage return and new line
+ header = header[:len(header)-2]
+
+ // Split on spaces, should be (PROXY <type> <remote addr> <local addr> <remote port> <local port>)
+ parts := strings.Split(header, " ")
+ if len(parts) < 2 {
+ p.conn.Close()
+ return &ErrBadHeader{[]byte(header)}
+ }
+
+ // Verify the type is known
+ switch parts[1] {
+ case "UNKNOWN":
+ if !p.acceptUnknown || len(parts) != 2 {
+ p.conn.Close()
+ return &ErrBadHeader{[]byte(header)}
+ }
+ p.remoteAddr = p.conn.LocalAddr()
+ p.localAddr = p.conn.RemoteAddr()
+ return nil
+ case "TCP4":
+ case "TCP6":
+ default:
+ p.conn.Close()
+ return &ErrBadAddressType{parts[1]}
+ }
+
+ if len(parts) != 6 {
+ p.conn.Close()
+ return &ErrBadHeader{[]byte(header)}
+ }
+
+ // Parse out the remote address
+ ip := net.ParseIP(parts[2])
+ if ip == nil {
+ p.conn.Close()
+ return &ErrBadRemote{parts[2], parts[4]}
+ }
+ port, err := strconv.Atoi(parts[4])
+ if err != nil {
+ p.conn.Close()
+ return &ErrBadRemote{parts[2], parts[4]}
+ }
+ p.remoteAddr = &net.TCPAddr{IP: ip, Port: port}
+
+ // Parse out the destination address
+ ip = net.ParseIP(parts[3])
+ if ip == nil {
+ p.conn.Close()
+ return &ErrBadLocal{parts[3], parts[5]}
+ }
+ port, err = strconv.Atoi(parts[5])
+ if err != nil {
+ p.conn.Close()
+ return &ErrBadLocal{parts[3], parts[5]}
+ }
+ p.localAddr = &net.TCPAddr{IP: ip, Port: port}
+
+ return nil
+}