Fix gosec slice bounds warnings

Add nolint directives for safe slice accesses where bounds
are guaranteed by fixed-size allocation or loop conditions.

Author: asayyah

header.go

@@ -111,9 +111,9 @@ func (h Header) Marshal() ([]byte, error) {
 	if h.Count > 31 {
 		return nil, errInvalidHeader
 	}
-	rawPacket[0] |= h.Count << countShift
+	rawPacket[0] |= h.Count << countShift //nolint:gosec // rawPacket is created with length headerLength (4)
 
-	rawPacket[1] = uint8(h.Type)
+	rawPacket[1] = uint8(h.Type) //nolint:gosec // rawPacket is created with length headerLength (4)
 
 	binary.BigEndian.PutUint16(rawPacket[2:], h.Length)
 

receiver_estimated_maximum_bitrate.go

@@ -276,7 +276,7 @@ func (p *ReceiverEstimatedMaximumBitrate) String() string {
 		powers++
 	}
 
-	unit := bitUnits[powers]
+	unit := bitUnits[powers] //nolint:gosec // powers is bounded by loop condition
 
 	return fmt.Sprintf("ReceiverEstimatedMaximumBitrate %x %.2f %s/s", p.SenderSSRC, bitrate, unit)
 }

reception_report.go

@@ -78,9 +78,9 @@ func (r ReceptionReport) Marshal() ([]byte, error) {
 		return nil, errInvalidTotalLost
 	}
 	tlBytes := rawPacket[totalLostOffset:]
-	tlBytes[0] = byte(r.TotalLost >> 16)
-	tlBytes[1] = byte(r.TotalLost >> 8)
-	tlBytes[2] = byte(r.TotalLost)
+	tlBytes[0] = byte(r.TotalLost >> 16) //nolint:gosec // rawPacket is created with length receptionReportLength (24)
+	tlBytes[1] = byte(r.TotalLost >> 8)  //nolint:gosec // rawPacket is created with length receptionReportLength (24)
+	tlBytes[2] = byte(r.TotalLost)       //nolint:gosec // rawPacket is created with length receptionReportLength (24)
 
 	binary.BigEndian.PutUint32(rawPacket[lastSeqOffset:], r.LastSequenceNumber)
 	binary.BigEndian.PutUint32(rawPacket[jitterOffset:], r.Jitter)

source_description.go

@@ -313,14 +313,14 @@ func (s SourceDescriptionItem) Marshal() ([]byte, error) {
 
 	rawPacket := make([]byte, sdesTypeLen+sdesOctetCountLen)
 
-	rawPacket[sdesTypeOffset] = uint8(s.Type)
+	rawPacket[sdesTypeOffset] = uint8(s.Type) //nolint:gosec // rawPacket is created with length 2
 
 	txtBytes := []byte(s.Text)
 	octetCount := len(txtBytes)
 	if octetCount > sdesMaxOctetCount {
 		return nil, errSDESTextTooLong
 	}
-	rawPacket[sdesOctetCountOffset] = uint8(octetCount)
+	rawPacket[sdesOctetCountOffset] = uint8(octetCount) //nolint:gosec // rawPacket is created with length 2
 
 	rawPacket = append(rawPacket, txtBytes...) //nolint:makezero
 

transport_layer_cc.go

@@ -270,7 +270,7 @@ func (r RecvDelta) Marshal() ([]byte, error) {
 	// small delta
 	if r.Type == TypeTCCPacketReceivedSmallDelta && delta >= 0 && delta <= math.MaxUint8 {
 		deltaChunk := make([]byte, 1)
-		deltaChunk[0] = byte(delta)
+		deltaChunk[0] = byte(delta) //nolint:gosec // deltaChunk is created with length 1
 
 		return deltaChunk, nil
 	}