Fix UnsubAck length check (#82)

at-wat · Jan 26, 2020 · be12606 · be12606
1 parent 0eea2ef
commit be12606
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Showing 2 changed files with 7 additions and 1 deletion.
diff --git a/packet_test.go b/packet_test.go
@@ -110,6 +110,9 @@ func TestPacketParseError(t *testing.T) {
 		"UnsubAck_InvalidFlag": {
 			0x01, []byte{}, &pktUnsubAck{}, ErrInvalidPacket,
 		},
+		"UnsubAck_ShortLength": {
+			0x00, []byte{}, &pktUnsubAck{}, ErrInvalidPacketLength,
+		},
 	}
 
 	for name, c := range cases {

diff --git a/unsuback.go b/unsuback.go
@@ -20,7 +20,10 @@ type pktUnsubAck struct {
 
 func (p *pktUnsubAck) Parse(flag byte, contents []byte) (*pktUnsubAck, error) {
 	if flag != 0 {
-		return nil, wrapError(ErrInvalidPacket, "parsing SUBACK")
+		return nil, wrapError(ErrInvalidPacket, "parsing UNSUBACK")
+	}
+	if len(contents) < 2 {
+		return nil, wrapError(ErrInvalidPacketLength, "parsing UNSUBACK")
 	}
 	p.ID = uint16(contents[0])<<8 | uint16(contents[1])
 	return p, nil