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Merged
sirzooro merged 1 commit into from
Jul 3, 2026
+89 −1
Merged

Check data length it RTP ExtHdr handlers #363

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87 changes: 87 additions & 0 deletions header_extension.go
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,18 @@ import (
"io"
)

/*
RFC 3550, RTP Header Extension:

0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| defined by profile | length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| header extension |
| .... |
*/

const (
headerExtensionIDReserved = 0xF
)
Expand Down Expand Up @@ -49,6 +61,10 @@ func (e *OneByteHeaderExtension) Set(id uint8, buf []byte) error {
payloadLen := int(e.payload[n]&^0xF0 + 1)
n++

if n+payloadLen > len(e.payload) {
break
}

if extid == id {
e.payload = append(e.payload[:n], append(buf, e.payload[n+payloadLen:]...)...)

Expand All @@ -70,6 +86,9 @@ func (e *OneByteHeaderExtension) Set(id uint8, buf []byte) error {

// GetIDs returns the available IDs.
func (e *OneByteHeaderExtension) GetIDs() []uint8 {
if len(e.payload) < 4 {
return nil
}
Comment on lines +89 to +91

@JoTurk JoTurk Jun 29, 2026

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It's a shame that we can't return an error.

@sirzooro sirzooro Jul 3, 2026

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Yeah. We could change this in RTP/v3. I will add comment there.

ids := make([]uint8, 0, binary.BigEndian.Uint16(e.payload[2:4]))
for n := 4; n < len(e.payload); {
if e.payload[n] == 0x00 { // padding
Expand All @@ -86,6 +105,10 @@ func (e *OneByteHeaderExtension) GetIDs() []uint8 {
break
}

if n+payloadLen > len(e.payload) {
break
}

ids = append(ids, extid)
n += payloadLen
}
Expand All @@ -106,6 +129,10 @@ func (e *OneByteHeaderExtension) Get(id uint8) []byte {
payloadLen := int(e.payload[n]&^0xF0 + 1)
n++

if n+payloadLen > len(e.payload) {
break
}

if extid == id {
return e.payload[n : n+payloadLen]
}
Expand All @@ -127,6 +154,10 @@ func (e *OneByteHeaderExtension) Del(id uint8) error {
extid := e.payload[n] >> 4
payloadLen := int(e.payload[n]&^0xF0 + 1)

if n+1+payloadLen > len(e.payload) {
break
}

if extid == id {
e.payload = append(e.payload[:n], e.payload[n+1+payloadLen:]...)

Expand All @@ -140,10 +171,17 @@ func (e *OneByteHeaderExtension) Del(id uint8) error {

// Unmarshal parses the extension payload.
func (e *OneByteHeaderExtension) Unmarshal(buf []byte) (int, error) {
if len(buf) < 4 {
return 0, errTooSmall
}
profile := binary.BigEndian.Uint16(buf[0:2])
if profile != ExtensionProfileOneByte {
return 0, fmt.Errorf("%w actual(%x)", errHeaderExtensionNotFound, buf[0:2])
}
extLen := binary.BigEndian.Uint16(buf[2:4])
if len(buf) < 4+int(extLen)*4 {
return 0, errTooSmall
}
e.payload = buf

return len(buf), nil
Expand Down Expand Up @@ -190,9 +228,17 @@ func (e *TwoByteHeaderExtension) Set(id uint8, buf []byte) error {
extid := e.payload[n]
n++

if n >= len(e.payload) {
break
}

payloadLen := int(e.payload[n])
n++

if n+payloadLen > len(e.payload) {
break
}

if extid == id {
e.payload = append(e.payload[:n], append(buf, e.payload[n+payloadLen:]...)...)

Expand All @@ -214,6 +260,9 @@ func (e *TwoByteHeaderExtension) Set(id uint8, buf []byte) error {

// GetIDs returns the available IDs.
func (e *TwoByteHeaderExtension) GetIDs() []uint8 {
if len(e.payload) < 4 {
return nil
}
ids := make([]uint8, 0, binary.BigEndian.Uint16(e.payload[2:4]))
for n := 4; n < len(e.payload); {
if e.payload[n] == 0x00 { // padding
Expand All @@ -225,9 +274,17 @@ func (e *TwoByteHeaderExtension) GetIDs() []uint8 {
extid := e.payload[n]
n++

if n >= len(e.payload) {
break
}

payloadLen := int(e.payload[n])
n++

if n+payloadLen > len(e.payload) {
break
}

ids = append(ids, extid)
n += payloadLen
}
Expand All @@ -247,9 +304,17 @@ func (e *TwoByteHeaderExtension) Get(id uint8) []byte {
extid := e.payload[n]
n++

if n >= len(e.payload) {
break
}

payloadLen := int(e.payload[n])
n++

if n+payloadLen > len(e.payload) {
break
}

if extid == id {
return e.payload[n : n+payloadLen]
}
Expand All @@ -270,8 +335,16 @@ func (e *TwoByteHeaderExtension) Del(id uint8) error {

extid := e.payload[n]

if n+1 >= len(e.payload) {
break
}

payloadLen := int(e.payload[n+1])

if n+2+payloadLen > len(e.payload) {
break
}

if extid == id {
e.payload = append(e.payload[:n], e.payload[n+2+payloadLen:]...)

Expand All @@ -285,10 +358,17 @@ func (e *TwoByteHeaderExtension) Del(id uint8) error {

// Unmarshal parses the extension payload.
func (e *TwoByteHeaderExtension) Unmarshal(buf []byte) (int, error) {
if len(buf) < 4 {
return 0, errTooSmall
}
profile := binary.BigEndian.Uint16(buf[0:2])
if profile != ExtensionProfileTwoByte {
return 0, fmt.Errorf("%w actual(%x)", errHeaderExtensionNotFound, buf[0:2])
}
extLen := binary.BigEndian.Uint16(buf[2:4])
if len(buf) < 4+int(extLen)*4 {
return 0, errTooSmall
}
e.payload = buf

return len(buf), nil
Expand Down Expand Up @@ -357,10 +437,17 @@ func (e *RawExtension) Del(id uint8) error {

// Unmarshal parses the extension from the given buffer.
func (e *RawExtension) Unmarshal(buf []byte) (int, error) {
if len(buf) < 4 {
return 0, errTooSmall
}
profile := binary.BigEndian.Uint16(buf[0:2])
if profile == ExtensionProfileOneByte || profile == ExtensionProfileTwoByte {
return 0, fmt.Errorf("%w actual(%x)", errHeaderExtensionNotFound, buf[0:2])
}
extLen := binary.BigEndian.Uint16(buf[2:4])
if len(buf) < 4+int(extLen)*4 {
return 0, errTooSmall
}
e.payload = buf

return len(buf), nil
Expand Down
3 changes: 2 additions & 1 deletion header_extension_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -303,7 +303,8 @@ func TestHeaderExtension_RFC8285TwoByteExtensionRewrite(t *testing.T) {

func TestHeaderExtension_Raw(t *testing.T) {
ext := &RawExtension{}
expectedPayload := []byte{0xBE, 0xEF}
// 4-byte raw extension: profile=0xBEEF (not one-byte/two-byte), length=0 words
expectedPayload := []byte{0xBE, 0xEF, 0x00, 0x00}

assert.Error(t, ext.Set(5, expectedPayload))
assert.NoError(t, ext.Set(0, expectedPayload))
Expand Down
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