server: compatible to old handshake protocol (pingcap#8812)

server/conn.go

@@ -248,6 +248,63 @@ type handshakeResponse41 struct {
  Attrs map[string]string
 }
 
+// parseOldHandshakeResponseHeader parses the old version handshake header HandshakeResponse320
+func parseOldHandshakeResponseHeader(packet *handshakeResponse41, data []byte) (parsedBytes int, err error) {
+ // Ensure there are enough data to read:
+ // https://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::HandshakeResponse320
+ log.Debugf("Try to parse hanshake response as Protocol::HandshakeResponse320 , packet data: %v", data)
+ if len(data) < 2+3 {
+ log.Errorf("Got malformed handshake response, packet data: %v", data)
+ return 0, mysql.ErrMalformPacket
+ }
+ offset := 0
+ // capability
+ capability := binary.LittleEndian.Uint16(data[:2])
+ packet.Capability = uint32(capability)
+
+ // be compatible with Protocol::HandshakeResponse41
+ packet.Capability = packet.Capability | mysql.ClientProtocol41
+
+ offset += 2
+ // skip max packet size
+ offset += 3
+ // usa default CharsetID
+ packet.Collation = mysql.CollationNames["utf8mb4_general_ci"]
+
+ return offset, nil
+}
+
+// parseOldHandshakeResponseBody parse the HandshakeResponse for Protocol::HandshakeResponse320 (except the common header part).
+func parseOldHandshakeResponseBody(packet *handshakeResponse41, data []byte, offset int) (err error) {
+ defer func() {
+ // Check malformat packet cause out of range is disgusting, but don't panic!
+ if r := recover(); r != nil {
+ log.Errorf("handshake panic, packet data: %v", data)
+ err = mysql.ErrMalformPacket
+ }
+ }()
+ // user name
+ packet.User = string(data[offset : offset+bytes.IndexByte(data[offset:], 0)])
+ offset += len(packet.User) + 1
+
+ if packet.Capability&mysql.ClientConnectWithDB > 0 {
+ if len(data[offset:]) > 0 {
+ idx := bytes.IndexByte(data[offset:], 0)
+ packet.DBName = string(data[offset : offset+idx])
+ offset = offset + idx + 1
+ }
+ if len(data[offset:]) > 0 {
+ packet.Auth = data[offset : offset+bytes.IndexByte(data[offset:], 0)]
+ offset += len(packet.Auth) + 1
+ }
+ } else {
+ packet.Auth = data[offset : offset+bytes.IndexByte(data[offset:], 0)]
+ offset += len(packet.Auth) + 1
+ }
+
+ return nil
+}
+
 // parseHandshakeResponseHeader parses the common header of SSLRequest and HandshakeResponse41.
 func parseHandshakeResponseHeader(packet *handshakeResponse41, data []byte) (parsedBytes int, err error) {
  // Ensure there are enough data to read:
@@ -368,9 +425,24 @@ func (cc *clientConn) readOptionalSSLRequestAndHandshakeResponse() error {
  return errors.Trace(err)
  }
 
+ isOldVersion := false
+
  var resp handshakeResponse41
+ var pos int
+
+ if len(data) < 2 {
+ log.Errorf("Got malformed handshake response, packet data: %v", data)
+ return mysql.ErrMalformPacket
+ }
+
+ capability := uint32(binary.LittleEndian.Uint16(data[:2]))
+ if capability&mysql.ClientProtocol41 > 0 {
+ pos, err = parseHandshakeResponseHeader(&resp, data)
+ } else {
+ pos, err = parseOldHandshakeResponseHeader(&resp, data)
+ isOldVersion = true
+ }
 
- pos, err := parseHandshakeResponseHeader(&resp, data)
  if err != nil {
  return errors.Trace(err)
  }
@@ -385,14 +457,23 @@ func (cc *clientConn) readOptionalSSLRequestAndHandshakeResponse() error {
  if err != nil {
  return errors.Trace(err)
  }
- pos, err = parseHandshakeResponseHeader(&resp, data)
+ if isOldVersion {
+ pos, err = parseOldHandshakeResponseHeader(&resp, data)
+ } else {
+ pos, err = parseHandshakeResponseHeader(&resp, data)
+ }
  if err != nil {
  return errors.Trace(err)
  }
  }
 
  // Read the remaining part of the packet.
- if err = parseHandshakeResponseBody(&resp, data, pos); err != nil {
+ if isOldVersion {
+ err = parseOldHandshakeResponseBody(&resp, data, pos)
+ } else {
+ err = parseHandshakeResponseBody(&resp, data, pos)
+ }
+ if err != nil {
  return errors.Trace(err)
  }
 
@@ -401,6 +482,7 @@ func (cc *clientConn) readOptionalSSLRequestAndHandshakeResponse() error {
  cc.dbname = resp.DBName
  cc.collation = resp.Collation
  cc.attrs = resp.Attrs
+
  err = cc.openSessionAndDoAuth(resp.Auth)
  return errors.Trace(err)
 }

server/conn_test.go

@@ -93,6 +93,20 @@ func (ts ConnTestSuite) TestParseHandshakeResponse(c *C) {
  c.Assert(err, IsNil)
  c.Assert(p.User, Equals, "pam")
  c.Assert(p.DBName, Equals, "test")
+
+ // Test for compatibility of Protocol::HandshakeResponse320
+ data = []byte{
+ 0x00, 0x80, 0x00, 0x00, 0x01, 0x72, 0x6f, 0x6f, 0x74, 0x00, 0x00,
+ }
+ p = handshakeResponse41{}
+ offset, err = parseOldHandshakeResponseHeader(&p, data)
+ c.Assert(err, IsNil)
+ capability = mysql.ClientProtocol41 |
+ mysql.ClientSecureConnection
+ c.Assert(p.Capability&capability, Equals, capability)
+ err = parseOldHandshakeResponseBody(&p, data, offset)
+ c.Assert(err, IsNil)
+ c.Assert(p.User, Equals, "root")
 }
 
 func (ts ConnTestSuite) TestIssue1768(c *C) {