Improve validation when establishing psql session

pkg/pgsql/errors/errors.go

@@ -39,7 +39,7 @@ var ErrMaxParamsNumberExceeded = errors.New("number of parameters exceeded the m
 var ErrParametersValueSizeTooLarge = errors.New("provided parameters exceeded the maximum allowed size limit")
 var ErrNegativeParameterValueLen = errors.New("negative parameter length detected")
 var ErrMalformedMessage = errors.New("malformed message detected")
-var ErrMessageTooLarge = errors.New("payload message hit  allowed memory boundaries")
+var ErrMessageTooLarge = errors.New("payload message hit allowed memory boundaries")
 
 func MapPgError(err error) (er bm.ErrorResp) {
 	switch {

pkg/pgsql/server/initialize_session.go

@@ -58,7 +58,7 @@ func (s *session) InitializeSession() (err error) {
 	s.protocolVersion = parseProtocolVersion(pvb)
 
 	// SSL Request packet
-	if s.protocolVersion == "1234.5679" {
+	if s.protocolVersion == pgmeta.PgsqlSSLRequestProtocolVersion {
 		if s.tlsConfig == nil || len(s.tlsConfig.Certificates) == 0 {
 			if _, err = s.writeMessage([]byte(`N`)); err != nil {
 				return err
@@ -86,8 +86,20 @@ func (s *session) InitializeSession() (err error) {
 		s.protocolVersion = parseProtocolVersion(pvb)
 	}
 
+	if !isValidProtocolVersion(s.protocolVersion) {
+		return fmt.Errorf("%w: %s", pgmeta.ErrInvalidPgsqlProtocolVersion, s.protocolVersion)
+	}
+
 	// startup message
-	connStringLenght := int(binary.BigEndian.Uint32(lb) - 4)
+	connStringLenght := int(binary.BigEndian.Uint32(lb) - 8)
+	if connStringLenght < 0 {
+		return pserr.ErrMalformedMessage
+	}
+
+	if connStringLenght > pgmeta.MaxMsgSize {
+		return pserr.ErrMessageTooLarge
+	}
+
 	connString := make([]byte, connStringLenght)
 
 	if _, err := s.mr.Read(connString); err != nil {
@@ -214,7 +226,7 @@ func (s *session) HandleStartup(ctx context.Context) (err error) {
 	}
 
 	// todo this is needed by jdbc driver. Here is added the minor supported version at the moment
-	if _, err := s.writeMessage(bm.ParameterStatus([]byte("server_version"), []byte(pgmeta.PgsqlProtocolVersion))); err != nil {
+	if _, err := s.writeMessage(bm.ParameterStatus([]byte("server_version"), []byte(pgmeta.PgsqlServerVersion))); err != nil {
 		return err
 	}
 
@@ -227,6 +239,10 @@ func parseProtocolVersion(payload []byte) string {
 	return fmt.Sprintf("%d.%d", major, minor)
 }
 
+func isValidProtocolVersion(version string) bool {
+	return version == pgmeta.PgsqlProtocolVersion || version == pgmeta.PgsqlSSLRequestProtocolVersion
+}
+
 func (s *session) Close() error {
 	s.mr.CloseConnection()
 

pkg/pgsql/server/pgmeta/pg_type.go

@@ -17,15 +17,21 @@ limitations under the License.
 package pgmeta
 
 import (
+	"errors"
 	"fmt"
 )
 
-const PgTypeMapOid = 0
-const PgTypeMapLength = 1
+const (
+	PgTypeMapOid    = 0
+	PgTypeMapLength = 1
 
-const PgsqlProtocolVersion = "9.6"
+	PgsqlProtocolVersion           = "3.0"
+	PgsqlSSLRequestProtocolVersion = "1234.5679"
+	PgsqlServerVersion             = "9.6"
+)
 
-var PgsqlProtocolVersionMessage = fmt.Sprintf("pgsql wire protocol %s or greater version implemented by immudb", PgsqlProtocolVersion)
+var PgsqlServerVersionMessage = fmt.Sprintf("pgsql server %s or greater version implemented by immudb", PgsqlServerVersion)
+var ErrInvalidPgsqlProtocolVersion = errors.New("invalid pgsql protocol version")
 
 // PgTypeMap maps the immudb type descriptor with pgsql pgtype map.
 // First int is the oid value (retrieved with select * from pg_type;)

pkg/pgsql/server/pgsql_integration_test.go

@@ -727,7 +727,7 @@ func TestPgsqlServer_VersionStatement(t *testing.T) {
 	var version string
 	err = db.QueryRow("SELECT version()").Scan(&version)
 	require.NoError(t, err)
-	require.Equal(t, pgmeta.PgsqlProtocolVersionMessage, version)
+	require.Equal(t, pgmeta.PgsqlServerVersionMessage, version)
 
 	_, err = db.Exec("DEALLOCATE \"_PLAN0x7fb2c0822800\"")
 	require.NoError(t, err)

pkg/pgsql/server/version.go

@@ -29,7 +29,7 @@ func (s *session) writeVersionInfo() error {
 	}
 	rows := []*schema.Row{{
 		Columns: []string{"version"},
-		Values:  []*schema.SQLValue{{Value: &schema.SQLValue_S{S: pgmeta.PgsqlProtocolVersionMessage}}},
+		Values:  []*schema.SQLValue{{Value: &schema.SQLValue_S{S: pgmeta.PgsqlServerVersionMessage}}},
 	}}
 	if _, err := s.writeMessage(bm.DataRow(rows, len(cols), nil)); err != nil {
 		return err