Bounds check the parser against two panics on malformed input

fix_int.go

@@ -31,6 +31,10 @@ const (
 
 // atoi is similar to the function in strconv, but is tuned for ints appearing in FIX field types.
 func atoi(d []byte) (int, error) {
+	if len(d) == 0 {
+		return 0, errors.New("empty bytes")
+	}
+
 	if d[0] == asciiMinus {
 		n, err := parseUInt(d[1:])
 		return (-1) * n, err

fix_int_test.go

@@ -35,6 +35,9 @@ func TestFIXInt_Read(t *testing.T) {
 
 	err = field.Read([]byte("blah"))
 	assert.NotNil(t, err, "Unexpected error")
+
+	err = field.Read([]byte(""))
+	assert.NotNil(t, err, "Unexpected error")
 }
 
 func TestFIXInt_Int(t *testing.T) {

message.go

@@ -553,6 +553,12 @@ func extractXMLDataField(parsedFieldBytes *TagValue, buffer []byte, dataLen int)
 		remBytes = buffer
 		return
 	}
+	// Compared against the remaining buffer so a large dataLen cannot overflow int.
+	if dataLen < 0 || dataLen > len(buffer)-endIndex-2 {
+		err = parseError{OrigError: fmt.Sprintf("extractXMLDataField: XMLDataLen %d exceeds remaining buffer of %d bytes", dataLen, len(buffer)-endIndex-2)}
+		remBytes = buffer
+		return
+	}
 	endIndex += dataLen + 1
 
 	err = parsedFieldBytes.parse(buffer[:endIndex+1])

message_test.go

@@ -64,6 +64,38 @@ func (s *MessageSuite) TestParseMessageEmpty() {
 	s.NotNil(err)
 }
 
+func (s *MessageSuite) TestParseMessageXMLDataLenOutOfRange() {
+	var tests = []struct {
+		name   string
+		rawMsg string
+	}{
+		{"overrun", "8=FIX.4.2
9=20
35=n
34=2
49=CME
56=OAEAAAN
212=999999999
213=<x/>
10=000
"},
+		{"int overflow", "8=FIX.4.2
9=20
35=n
34=2
49=CME
56=OAEAAAN
212=9223372036854775807
213=<x/>
10=000
"},
+	}
+
+	for _, test := range tests {
+		s.Run(test.name, func() {
+			s.NotNil(ParseMessage(NewMessage(), bytes.NewBufferString(test.rawMsg)))
+		})
+	}
+}
+
+func (s *MessageSuite) TestParseMessageEmptyIntField() {
+	var tests = []struct {
+		name   string
+		rawMsg string
+	}{
+		{"body length", "8=FIX.4.2
9=
35=D
34=2
49=TW
56=ISLD
10=000
"},
+		{"xml data len", "8=FIX.4.2
9=20
35=n
34=2
49=CME
56=OAEAAAN
212=
213=<x/>
10=000
"},
+	}
+
+	for _, test := range tests {
+		s.Run(test.name, func() {
+			s.NotNil(ParseMessage(NewMessage(), bytes.NewBufferString(test.rawMsg)))
+		})
+	}
+}
+
 func (s *MessageSuite) TestParseMessage() {
 	rawMsg := bytes.NewBufferString("8=FIX.4.2
9=104
35=D
34=2
49=TW
52=20140515-19:49:56.659
56=ISLD
11=100
21=1
40=1
54=1
55=TSLA
60=00010101-00:00:00.000
10=039
")