Fix panic on malformed playlists

reader.go

@@ -26,8 +26,8 @@ var reKeyValue = regexp.MustCompile(`([a-zA-Z0-9_-]+)=("[^"]+"|[^",]+)`)
 
 // TimeParse allows globally apply and/or override Time Parser function.
 // Available variants:
-//		* FullTimeParse - implements full featured ISO/IEC 8601:2004
-//		* StrictTimeParse - implements only RFC3339 Nanoseconds format
+//   - FullTimeParse - implements full featured ISO/IEC 8601:2004
+//   - StrictTimeParse - implements only RFC3339 Nanoseconds format
 var TimeParse func(value string) (time.Time, error) = FullTimeParse
 
 // Decode parses a master playlist passed from the buffer. If `strict`
@@ -536,7 +536,9 @@ func decodeLineOfMediaPlaylist(p *MediaPlaylist, wv *WV, state *decodingState, l
 		}
 		// If EXT-X-KEY appeared before reference to segment (EXTINF) then it linked to this segment
 		if state.tagKey {
-			p.Segments[p.last()].Key = &Key{state.xkey.Method, state.xkey.URI, state.xkey.IV, state.xkey.Keyformat, state.xkey.Keyformatversions}
+			if segment := p.Segments[p.last()]; segment != nil {
+				segment.Key = &Key{state.xkey.Method, state.xkey.URI, state.xkey.IV, state.xkey.Keyformat, state.xkey.Keyformatversions}
+			}
 			// First EXT-X-KEY may appeared in the header of the playlist and linked to first segment
 			// but for convenient playlist generation it also linked as default playlist key
 			if p.Key == nil {
@@ -546,7 +548,9 @@ func decodeLineOfMediaPlaylist(p *MediaPlaylist, wv *WV, state *decodingState, l
 		}
 		// If EXT-X-MAP appeared before reference to segment (EXTINF) then it linked to this segment
 		if state.tagMap {
-			p.Segments[p.last()].Map = &Map{state.xmap.URI, state.xmap.Limit, state.xmap.Offset}
+			if segment := p.Segments[p.last()]; segment != nil {
+				segment.Map = &Map{state.xmap.URI, state.xmap.Limit, state.xmap.Offset}
+			}
 			// First EXT-X-MAP may appeared in the header of the playlist and linked to first segment
 			// but for convenient playlist generation it also linked as default playlist map
 			if p.Map == nil {
@@ -557,7 +561,9 @@ func decodeLineOfMediaPlaylist(p *MediaPlaylist, wv *WV, state *decodingState, l
 
 		// if segment custom tag appeared before EXTINF then it links to this segment
 		if state.tagCustom {
-			p.Segments[p.last()].Custom = state.custom
+			if segment := p.Segments[p.last()]; segment != nil {
+				segment.Custom = state.custom
+			}
 			state.custom = make(map[string]CustomTag)
 			state.tagCustom = false
 		}
@@ -759,7 +765,7 @@ func decodeLineOfMediaPlaylist(p *MediaPlaylist, wv *WV, state *decodingState, l
 		if err == nil {
 			state.tagWV = true
 		}
-	case strings.HasPrefix(line, "#WV-CYPHER-VERSION"):
+	case strings.HasPrefix(line, "#WV-CYPHER-VERSION "):
 		state.listType = MEDIA
 		wv.CypherVersion = line[19:]
 		state.tagWV = true
@@ -803,7 +809,7 @@ func decodeLineOfMediaPlaylist(p *MediaPlaylist, wv *WV, state *decodingState, l
 		if err == nil {
 			state.tagWV = true
 		}
-	case strings.HasPrefix(line, "#WV-VIDEO-RESOLUTION"):
+	case strings.HasPrefix(line, "#WV-VIDEO-RESOLUTION "):
 		state.listType = MEDIA
 		wv.VideoResolution = line[21:]
 		state.tagWV = true

reader_test.go

@@ -1,11 +1,11 @@
 /*
- Playlist parsing tests.
+Playlist parsing tests.
 
- Copyright 2013-2019 The Project Developers.
- See the AUTHORS and LICENSE files at the top-level directory of this distribution
- and at https://github.com/grafov/m3u8/
+Copyright 2013-2019 The Project Developers.
+See the AUTHORS and LICENSE files at the top-level directory of this distribution
+and at https://github.com/grafov/m3u8/
 
- ॐ तारे तुत्तारे तुरे स्व
+ॐ तारे तुत्तारे तुरे स्व
 */
 package m3u8
 
@@ -972,6 +972,113 @@ func TestDecodeMediaPlaylistStartTime(t *testing.T) {
 	}
 }
 
+/********************
+ *  Bad data tests  *
+ ********************/
+
+// Test mallformed playlist
+func TestMalformedMasterPlaylis(t *testing.T) {
+	data := []byte("#EXT-X-START:\n#EXTM3U")
+	_, _, err := DecodeFrom(bytes.NewReader(data), true)
+	if err != nil {
+		if !errors.Is(err, ErrorNoEXTM3U) {
+			t.Errorf("Wrong error type at DecodeFrom: %s", err)
+		}
+	} else {
+		t.Error("No error on malformed playlist on DecodeFrome")
+	}
+	if _, _, err := DecodeFrom(bytes.NewReader(data), false); err != nil {
+		t.Errorf("Unexpected error on not strict mode of parsing: %s", err)
+	}
+
+	var master = new(MasterPlaylist)
+	err = master.DecodeFrom(bytes.NewReader(data), true)
+	if err != nil {
+		if !errors.Is(err, ErrorNoEXTM3U) {
+			t.Errorf("Wrong error type at (*MasterPlaylist).DecodeFrom: %s",
+				err)
+		}
+	} else {
+		t.Error("No error on malformed playlist on (*MasterPlaylist).DecodeFrome")
+	}
+
+	if err := master.DecodeFrom(bytes.NewReader(data), false); err != nil {
+		t.Errorf("Unexpected error on not strict mode of parsing: %s", err)
+	}
+
+	var media = new(MediaPlaylist)
+	err = media.DecodeFrom(bytes.NewReader(data), true)
+	if err != nil {
+		if !errors.Is(err, ErrorNoEXTM3U) {
+			t.Errorf("Wrong error type at (*MediaPlaylist).DecodeFrom: %s",
+				err)
+		}
+	} else {
+		// TODO: There is probably an error here. The
+		// tag EXT-X-START should only appear in the master playlist.
+		t.Error("No error on malformed playlist on (*MediaPlaylist).DecodeFrome")
+	}
+	if err := media.DecodeFrom(bytes.NewReader(data), false); err != nil {
+		t.Errorf("Unexpected error on not strict mode of parsing: %s", err)
+	}
+
+}
+
+func TestDecodeMediaPlaylistDicontinuityAtBegin(t *testing.T) {
+	f, err := os.Open("sample-playlists/media-with-discontinuity-at-start.m3u8")
+	if err != nil {
+		t.Fatal(err)
+	}
+	p, listType, err := DecodeFrom(bufio.NewReader(f), true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	pp := p.(*MediaPlaylist)
+	CheckType(t, pp)
+	if listType != MEDIA {
+		t.Error("Sample not recognized as media playlist.")
+	}
+	if pp.StartTime != float64(0.0) {
+		t.Errorf("Media segment StartTime != 0: %f", pp.StartTime)
+	}
+}
+
+// Test for https://github.com/khenarghot/m3u8/issues/3
+func TestMellformedPanicIssue3(t *testing.T) {
+	bad := bytes.NewBuffer([]byte(`#WV-CYPHER-VERSION`))
+	_, _, err := DecodeFrom(bad, true)
+	if err == nil {
+		t.Fail()
+	}
+}
+
+// Test for https://github.com/khenarghot/m3u8/issues/1
+func TestMellformedPanicIssue1(t *testing.T) {
+	bad := bytes.NewBuffer([]byte(`#WV-VIDEO-RESOLUTION`))
+	_, _, err := DecodeFrom(bad, true)
+	if err == nil {
+		t.Fail()
+	}
+}
+
+// Test for https://github.com/khenarghot/m3u8/issues/2
+func TestMellformedPanicIssue2(t *testing.T) {
+	bad := bytes.NewBuffer([]byte("#EXT-X-KEY:\n0"))
+	_, _, err := DecodeFrom(bad, false)
+	if err != nil {
+		t.Fail()
+	}
+}
+
+// Test for https://github.com/khenarghot/m3u8/issues/2
+func TestMellformedPanicIssue2AltMAP(t *testing.T) {
+	bad := bytes.NewBuffer([]byte("#EXT-X-MAP:\n0"))
+	_, _, err := DecodeFrom(bad, false)
+	if err != nil {
+		t.Fail()
+	}
+}
+
 /****************
  *  Benchmarks  *
  ****************/