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Bug which caused the connection to not close in case of error writing an error packet #6977

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merged 1 commit into from
Nov 2, 2020
Merged

Bug which caused the connection to not close in case of error writing an error packet #6977

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27 changes: 14 additions & 13 deletions go/mysql/conn.go
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -947,14 +947,14 @@ func (c *Conn) handleComStmtSendLongData(data []byte) bool {
prepare, ok := c.PrepareData[stmtID]
if !ok {
err := fmt.Errorf("got wrong statement id from client %v, statement ID(%v) is not found from record", c.ConnectionID, stmtID)
return !c.writeErrorPacketFromErrorAndLog(err)
return c.writeErrorPacketFromErrorAndLog(err)
}

if prepare.BindVars == nil ||
prepare.ParamsCount == uint16(0) ||
paramID >= prepare.ParamsCount {
err := fmt.Errorf("invalid parameter Number from client %v, statement: %v", c.ConnectionID, prepare.PrepareStmt)
return !c.writeErrorPacketFromErrorAndLog(err)
return c.writeErrorPacketFromErrorAndLog(err)
}

chunk := make([]byte, len(chunkData))
Expand Down Expand Up @@ -990,7 +990,7 @@ func (c *Conn) handleComStmtExecute(handler Handler, data []byte) (kontinue bool
}

if err != nil {
return !c.writeErrorPacketFromErrorAndLog(err)
return c.writeErrorPacketFromErrorAndLog(err)
}

fieldSent := false
Expand Down Expand Up @@ -1065,14 +1065,15 @@ func (c *Conn) handleComPrepare(handler Handler, data []byte) bool {

var queries []string
if c.Capabilities&CapabilityClientMultiStatements != 0 {
queries, err := sqlparser.SplitStatementToPieces(query)
var err error
queries, err = sqlparser.SplitStatementToPieces(query)
if err != nil {
log.Errorf("Conn %v: Error splitting query: %v", c, err)
return !c.writeErrorPacketFromErrorAndLog(err)
return c.writeErrorPacketFromErrorAndLog(err)
}
if len(queries) != 1 {
log.Errorf("Conn %v: can not prepare multiple statements", c, err)
return !c.writeErrorPacketFromErrorAndLog(err)
return c.writeErrorPacketFromErrorAndLog(err)
}
} else {
queries = []string{query}
Expand Down Expand Up @@ -1121,7 +1122,7 @@ func (c *Conn) handleComPrepare(handler Handler, data []byte) bool {
fld, err := handler.ComPrepare(c, queries[0], bindVars)

if err != nil {
return !c.writeErrorPacketFromErrorAndLog(err)
return c.writeErrorPacketFromErrorAndLog(err)
}

if err := c.writePrepare(fld, c.PrepareData[c.StatementID]); err != nil {
Expand Down Expand Up @@ -1194,7 +1195,7 @@ func (c *Conn) handleComQuery(handler Handler, data []byte) (kontinue bool) {
queries, err = sqlparser.SplitStatementToPieces(query)
if err != nil {
log.Errorf("Conn %v: Error splitting query: %v", c, err)
return !c.writeErrorPacketFromErrorAndLog(err)
return c.writeErrorPacketFromErrorAndLog(err)
}
} else {
queries = []string{query}
Expand All @@ -1215,7 +1216,7 @@ func (c *Conn) handleComQuery(handler Handler, data []byte) (kontinue bool) {
}

func (c *Conn) execQuery(query string, handler Handler, more bool) execResult {
fieldSent := false
callbackCalled := false
// sendFinished is set if the response should just be an OK packet.
sendFinished := false

Expand All @@ -1229,8 +1230,8 @@ func (c *Conn) execQuery(query string, handler Handler, more bool) execResult {
return io.EOF
}

if !fieldSent {
fieldSent = true
if !callbackCalled {
callbackCalled = true

if len(qr.Fields) == 0 {
sendFinished = true
Expand Down Expand Up @@ -1259,8 +1260,8 @@ func (c *Conn) execQuery(query string, handler Handler, more bool) execResult {
return c.writeRows(qr)
})

// If no field was sent, we expect an error.
if !fieldSent {
// If callback was not called, we expect an error.
if !callbackCalled {
// This is just a failsafe. Should never happen.
if err == nil || err == io.EOF {
err = NewSQLErrorFromError(errors.New("unexpected: query ended without no results and no error"))
Expand Down
120 changes: 120 additions & 0 deletions go/mysql/conn_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -482,6 +482,65 @@ func TestInitDbAgainstWrongDbDoesNotDropConnection(t *testing.T) {
require.EqualValues(t, data[0], ErrPacket) // we should see the error here
}

func TestConnectionErrorWhileWritingComQuery(t *testing.T) {
// Set the conn for the server connection to the simulated connection which always returns an error on writing
sConn := newConn(testConn{
writeToPass: []bool{false, true},
pos: -1,
queryPacket: []byte{0x21, 0x00, 0x00, 0x00, ComQuery, 0x73, 0x65, 0x6c, 0x65, 0x63, 0x74, 0x20, 0x40, 0x40, 0x76, 0x65, 0x72, 0x73,
0x69, 0x6f, 0x6e, 0x5f, 0x63, 0x6f, 0x6d, 0x6d, 0x65, 0x6e, 0x74, 0x20, 0x6c, 0x69, 0x6d, 0x69, 0x74, 0x20, 0x31},
})

// this handler will return an error on the first run, and fail the test if it's run more times
errorString := make([]byte, 17000)
handler := &singleRun{t: t, err: fmt.Errorf(string(errorString))}
res := sConn.handleNextCommand(handler)
require.False(t, res, "we should beak the connection in case of error writing error packet")
}

func TestConnectionErrorWhileWritingComStmtSendLongData(t *testing.T) {
// Set the conn for the server connection to the simulated connection which always returns an error on writing
sConn := newConn(testConn{
writeToPass: []bool{false, true},
pos: -1,
queryPacket: []byte{0x21, 0x00, 0x00, 0x00, ComStmtSendLongData, 0x73, 0x65, 0x6c, 0x65, 0x63, 0x74, 0x20, 0x40, 0x40, 0x76, 0x65, 0x72, 0x73,
0x69, 0x6f, 0x6e, 0x5f, 0x63, 0x6f, 0x6d, 0x6d, 0x65, 0x6e, 0x74, 0x20, 0x6c, 0x69, 0x6d, 0x69, 0x74, 0x20, 0x31},
})

// this handler will return an error on the first run, and fail the test if it's run more times
handler := &singleRun{t: t, err: fmt.Errorf("not used")}
res := sConn.handleNextCommand(handler)
require.False(t, res, "we should beak the connection in case of error writing error packet")
}

func TestConnectionErrorWhileWritingComPrepare(t *testing.T) {
// Set the conn for the server connection to the simulated connection which always returns an error on writing
sConn := newConn(testConn{
writeToPass: []bool{false},
pos: -1,
queryPacket: []byte{0x01, 0x00, 0x00, 0x00, ComPrepare},
})
sConn.Capabilities = sConn.Capabilities | CapabilityClientMultiStatements
// this handler will return an error on the first run, and fail the test if it's run more times
handler := &singleRun{t: t, err: fmt.Errorf("not used")}
res := sConn.handleNextCommand(handler)
require.False(t, res, "we should beak the connection in case of error writing error packet")
}

func TestConnectionErrorWhileWritingComStmtExecute(t *testing.T) {
// Set the conn for the server connection to the simulated connection which always returns an error on writing
sConn := newConn(testConn{
writeToPass: []bool{false},
pos: -1,
queryPacket: []byte{0x21, 0x00, 0x00, 0x00, ComStmtExecute, 0x73, 0x65, 0x6c, 0x65, 0x63, 0x74, 0x20, 0x40, 0x40, 0x76, 0x65, 0x72, 0x73,
0x69, 0x6f, 0x6e, 0x5f, 0x63, 0x6f, 0x6d, 0x6d, 0x65, 0x6e, 0x74, 0x20, 0x6c, 0x69, 0x6d, 0x69, 0x74, 0x20, 0x31},
})
// this handler will return an error on the first run, and fail the test if it's run more times
handler := &singleRun{t: t, err: fmt.Errorf("not used")}
res := sConn.handleNextCommand(handler)
require.False(t, res, "we should beak the connection in case of error writing error packet")
}

type singleRun struct {
hasRun bool
t *testing.T
Expand Down Expand Up @@ -522,3 +581,64 @@ func (h *singleRun) ComResetConnection(*Conn) {
}

var _ Handler = (*singleRun)(nil)

type testConn struct {
writeToPass []bool
pos int
queryPacket []byte
}

func (t testConn) Read(b []byte) (n int, err error) {
for j, i := range t.queryPacket {
b[j] = i
}
return len(b), nil
}

func (t testConn) Write(b []byte) (n int, err error) {
t.pos = t.pos + 1
if t.writeToPass[t.pos] {
return 0, nil
}
return 0, fmt.Errorf("error in writing to connection")
}

func (t testConn) Close() error {
panic("implement me")
}

func (t testConn) LocalAddr() net.Addr {
panic("implement me")
}

func (t testConn) RemoteAddr() net.Addr {
return mockAddress{s: "a"}
}

func (t testConn) SetDeadline(t1 time.Time) error {
panic("implement me")
}

func (t testConn) SetReadDeadline(t1 time.Time) error {
panic("implement me")
}

func (t testConn) SetWriteDeadline(t1 time.Time) error {
panic("implement me")
}

var _ net.Conn = (*testConn)(nil)

type mockAddress struct {
s string
}

func (m mockAddress) Network() string {
return m.s
}

func (m mockAddress) String() string {
return m.s
}

var _ net.Addr = (*mockAddress)(nil)