fixed reading connection attributes on server side

go.mod

@@ -14,6 +14,7 @@ require (
 	github.com/shopspring/decimal v0.0.0-20180709203117-cd690d0c9e24
 	github.com/siddontang/go v0.0.0-20180604090527-bdc77568d726
 	github.com/siddontang/go-log v0.0.0-20180807004314-8d05993dda07
+	github.com/stretchr/testify v1.7.0
 	go.uber.org/multierr v1.6.0 // indirect
 	go.uber.org/zap v1.16.0 // indirect
 	golang.org/x/text v0.3.6 // indirect

go.sum

@@ -51,10 +51,12 @@ github.com/siddontang/go v0.0.0-20180604090527-bdc77568d726 h1:xT+JlYxNGqyT+XcU8
 github.com/siddontang/go v0.0.0-20180604090527-bdc77568d726/go.mod h1:3yhqj7WBBfRhbBlzyOC3gUxftwsU0u8gqevxwIHQpMw=
 github.com/siddontang/go-log v0.0.0-20180807004314-8d05993dda07 h1:oI+RNwuC9jF2g2lP0u0cVEEZrc/AYBCuFdvwrLWM/6Q=
 github.com/siddontang/go-log v0.0.0-20180807004314-8d05993dda07/go.mod h1:yFdBgwXP24JziuRl2NMUahT7nGLNOKi1SIiFxMttVD4=
+github.com/stretchr/objx v0.1.0 h1:4G4v2dO3VZwixGIRoQ5Lfboy6nUhCyYzaqnIAPPhYs4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
-github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 go.uber.org/atomic v1.3.2/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/atomic v1.6.0/go.mod h1:sABNBOSYdrvTF6hTgEIbc7YasKWGhgEQZyfxyTvoXHQ=
@@ -112,5 +114,7 @@ gopkg.in/natefinch/lumberjack.v2 v2.0.0 h1:1Lc07Kr7qY4U2YPouBjpCLxpiyxIVoxqXgkXL
 gopkg.in/natefinch/lumberjack.v2 v2.0.0/go.mod h1:l0ndWWf7gzL7RNwBG7wST/UCcT4T24xpD6X8LsfU/+k=
 gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 honnef.co/go/tools v0.0.1-2019.2.3 h1:3JgtbtFHMiCmsznwGVTUWbgGov+pVqnlf1dEJTNAXeM=
 honnef.co/go/tools v0.0.1-2019.2.3/go.mod h1:a3bituU0lyd329TUQxRnasdCoJDkEUEAqEt0JzvZhAg=

server/handshake_resp.go

@@ -30,7 +30,7 @@ func (c *Conn) readHandshakeResponse() error {
 
 	pos = c.readPluginName(data, pos)
 
-	cont, err := c.handleAuthMatch(authData, pos)
+	cont, err := c.handleAuthMatch()
 	if err != nil {
 		return err
 	}
@@ -130,7 +130,7 @@ func (c *Conn) readDb(data []byte, pos int) (int, error) {
 func (c *Conn) readPluginName(data []byte, pos int) int {
 	if c.capability&CLIENT_PLUGIN_AUTH != 0 {
 		c.authPluginName = string(data[pos : pos+bytes.IndexByte(data[pos:], 0x00)])
-		pos += len(c.authPluginName)
+		pos += len(c.authPluginName) + 1
 	} else {
 		// The method used is Native Authentication if both CLIENT_PROTOCOL_41 and CLIENT_SECURE_CONNECTION are set,
 		// but CLIENT_PLUGIN_AUTH is not set, so we fallback to 'mysql_native_password'
@@ -191,7 +191,7 @@ func (c *Conn) handlePublicKeyRetrieval(authData []byte) (bool, error) {
 	return true, nil
 }
 
-func (c *Conn) handleAuthMatch(authData []byte, pos int) (bool, error) {
+func (c *Conn) handleAuthMatch() (bool, error) {
 	// if the client responds the handshake with a different auth method, the server will send the AuthSwitchRequest packet
 	// to the client to ask the client to switch.
 
@@ -207,17 +207,29 @@ func (c *Conn) handleAuthMatch(authData []byte, pos int) (bool, error) {
 }
 
 func (c *Conn) readAttributes(data []byte, pos int) (int, error) {
-	attrs := make(map[string]string)
+	// read length of attribute data
+	attrLen, isNull, skip := LengthEncodedInt(data[pos:])
+	pos += skip
+	if isNull {
+		return pos, nil
+	}
+
+	if len(data) < pos+int(attrLen) {
+		return pos, errors.New("corrupt attributes data")
+	}
+
 	i := 0
+	attrs := make(map[string]string)
 	var key string
 
+	// read until end of data or NUL for atrribute key/values
 	for {
 		str, isNull, strLen, err := LengthEncodedString(data[pos:])
-
 		if err != nil {
 			return -1, err
 		}
 
+		// end of data
 		if isNull {
 			break
 		}

server/handshake_resp_test.go

@@ -4,7 +4,9 @@ import (
 	"bytes"
 	"testing"
 
+	"github.com/go-mysql-org/go-mysql/mocks"
 	"github.com/go-mysql-org/go-mysql/mysql"
+	"github.com/stretchr/testify/mock"
 )
 
 func TestReadAuthData(t *testing.T) {
@@ -53,6 +55,120 @@ func TestDecodeFirstPart(t *testing.T) {
 	}
 }
 
+func TestReadDB(t *testing.T) {
+	handler := &mocks.Handler{}
+	c := &Conn{
+		h: handler,
+	}
+	c.SetCapability(mysql.CLIENT_CONNECT_WITH_DB)
+	var dbName string
+
+	// when handler's UseDB is called, copy dbName to local variable
+	handler.On("UseDB", mock.IsType("")).Return(nil).Once().RunFn = func(args mock.Arguments) {
+		dbName = args[0].(string)
+	}
+
+	// example data from
+	// https://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::HandshakeResponse41
+	data := []byte{
+		0x54, 0x00, 0x00, 0x01, 0x8d, 0xa6, 0x0f, 0x00, 0x00, 0x00, 0x00, 0x01,
+		0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		0x70, 0x61, 0x6d, 0x00, 0x14, 0xab, 0x09, 0xee, 0xf6, 0xbc, 0xb1, 0x32,
+		0x3e, 0x61, 0x14, 0x38, 0x65, 0xc0, 0x99, 0x1d, 0x95, 0x7d, 0x75, 0xd4,
+		0x47, 0x74, 0x65, 0x73, 0x74, 0x00, 0x6d, 0x79, 0x73, 0x71, 0x6c, 0x5f,
+		0x6e, 0x61, 0x74, 0x69, 0x76, 0x65, 0x5f, 0x70, 0x61, 0x73, 0x73, 0x77,
+		0x6f, 0x72, 0x64, 0x00,
+	}
+	pos := 61
+
+	var err error
+	pos, err = c.readDb(data, pos)
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err.Error())
+	}
+
+	if pos != 66 { // 61 + len("test") + 1
+		t.Fatalf("unexpected pos, got %d", pos)
+	}
+
+	if dbName != "test" {
+		t.Fatalf("unexpected db, got %s", dbName)
+	}
+
+	handler.AssertExpectations(t)
+}
+
+func TestReadPluginName(t *testing.T) {
+	// example data from
+	// https://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::HandshakeResponse41
+	mysqlNativePassword := []byte{
+		0x54, 0x00, 0x00, 0x01, 0x8d, 0xa6, 0x0f, 0x00, 0x00, 0x00, 0x00,
+		0x01, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x70, 0x61, 0x6d, 0x00, 0x14, 0xab, 0x09, 0xee,
+		0xf6, 0xbc, 0xb1, 0x32, 0x3e, 0x61, 0x14, 0x38, 0x65, 0xc0, 0x99,
+		0x1d, 0x95, 0x7d, 0x75, 0xd4, 0x47, 0x74, 0x65, 0x73, 0x74, 0x00,
+		0x6d, 0x79, 0x73, 0x71, 0x6c, 0x5f, 0x6e, 0x61, 0x74, 0x69, 0x76,
+		0x65, 0x5f, 0x70, 0x61, 0x73, 0x73, 0x77, 0x6f, 0x72, 0x64, 0x00,
+	}
+
+	// altered example data so it has different auth plugin
+	otherPlugin := []byte{
+		0x54, 0x00, 0x00, 0x01, 0x8d, 0xa6, 0x0f, 0x00, 0x00, 0x00, 0x00,
+		0x01, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x70, 0x61, 0x6d, 0x00, 0x14, 0xab, 0x09, 0xee,
+		0xf6, 0xbc, 0xb1, 0x32, 0x3e, 0x61, 0x14, 0x38, 0x65, 0xc0, 0x99,
+		0x1d, 0x95, 0x7d, 0x75, 0xd4, 0x47, 0x74, 0x65, 0x73, 0x74, 0x00,
+		0x66, 0x6f, 0x6f, 0x62, 0x61, 0x72, 0x00,
+	}
+
+	t.Run("mysql_native_password from plugin name", func(t *testing.T) {
+		c := &Conn{}
+		c.SetCapability(mysql.CLIENT_PLUGIN_AUTH)
+		pos := 66
+
+		pos = c.readPluginName(mysqlNativePassword, pos)
+		if pos != 88 { // 66 + len("mysql_native_password") + 1
+			t.Fatalf("unexpected pos, got %d", pos)
+		}
+
+		if c.authPluginName != "mysql_native_password" {
+			t.Fatalf("unexpected plugin name, got %s", c.authPluginName)
+		}
+	})
+
+	t.Run("other plugin", func(t *testing.T) {
+		c := &Conn{}
+		c.SetCapability(mysql.CLIENT_PLUGIN_AUTH)
+		pos := 66
+
+		pos = c.readPluginName(otherPlugin, pos)
+		if pos != 73 { // 66 + len("foobar") + 1
+			t.Fatalf("unexpected pos, got %d", pos)
+		}
+
+		if c.authPluginName != "foobar" {
+			t.Fatalf("unexpected plugin name, got %s", c.authPluginName)
+		}
+	})
+
+	t.Run("mysql_native_password as default", func(t *testing.T) {
+		c := &Conn{}
+		pos := 123 // can be anything
+
+		pos = c.readPluginName(mysqlNativePassword, pos)
+		if pos != 123 { // capability not set, so same as initial pos
+			t.Fatalf("unexpected pos, got %d", pos)
+		}
+
+		if c.authPluginName != mysql.AUTH_NATIVE_PASSWORD {
+			t.Fatalf("unexpected plugin name, got %s", c.authPluginName)
+		}
+	})
+}
+
 func TestReadAttributes(t *testing.T) {
 	var err error
 	// example data from
@@ -75,7 +191,7 @@ func TestReadAttributes(t *testing.T) {
 		0x6d, 0x06, 0x78, 0x38, 0x36, 0x5f, 0x36, 0x34, 0x03, 0x66, 0x6f, 0x6f,
 		0x03, 0x62, 0x61, 0x72,
 	}
-	pos := 85
+	pos := 84
 
 	c := &Conn{}