streaming

commit f06b871300334ace54d1d6c9678156a53cfcff65
parent 8c5823d831ca8c25cf4b0e1119b049acf32e3471
Author: blackfalcon <blackfalcon.ru@gmail.com>
Date:   Tue, 28 May 2024 08:30:22 -0300

m3u8: validate closed captions when parsing

Resolves https://github.com/untangledco/streaming/issues/6

Diffstat:
M
m3u8/parse.go
 | 
14
++++++++------

1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/m3u8/parse.go b/m3u8/parse.go
@@ -308,13 +308,15 @@ func parseCCInfo(s string) (*CCInfo, error) {
 	if len(s) < 3 {
 		return nil, fmt.Errorf("too short")
 	}
-	if s[:1] == "CC" {
-		// TODO(otl): compare against literals '1', '2', '3', '4' instead of parsing.
-		i, err := strconv.Atoi(string(s[2]))
-		if err != nil {
-			return nil, fmt.Errorf("parse channel number: %w", err)
+	if s[:2] == "CC" {
+		// MUST have one of the values: "CC1", "CC2", "CC3", "CC4"
+		switch {
+		case len(s) == 3 && s[2] >= '1' && s[2] <= '4':
+			i := int(s[2] - '0')
+			return &CCInfo{i, false}, nil
+		default:
+			return nil, fmt.Errorf("invalid closed caption %s", s)
 		}
-		return &CCInfo{i, false}, nil
 	}
 	// SERVICE00
 	if len(s) < 8 {