mirror of
https://github.com/bluenviron/mediamtx
synced 2025-02-02 12:42:21 +00:00
116 lines
2.5 KiB
Go
116 lines
2.5 KiB
Go
package handshake
|
|
|
|
import (
|
|
"bytes"
|
|
"crypto/rand"
|
|
"fmt"
|
|
"io"
|
|
)
|
|
|
|
const (
|
|
c2s2Size = c1s1Size
|
|
c2s2DigestPos = c2s2Size - 8 - digestLength
|
|
)
|
|
|
|
var (
|
|
randomCrud = []byte{
|
|
0xf0, 0xee, 0xc2, 0x4a, 0x80, 0x68, 0xbe, 0xe8,
|
|
0x2e, 0x00, 0xd0, 0xd1, 0x02, 0x9e, 0x7e, 0x57,
|
|
0x6e, 0xec, 0x5d, 0x2d, 0x29, 0x80, 0x6f, 0xab,
|
|
0x93, 0xb8, 0xe6, 0x36, 0xcf, 0xeb, 0x31, 0xae,
|
|
}
|
|
clientKeyC2 = append([]byte(nil), append(clientKeyC1, randomCrud...)...)
|
|
serverKeyS2 = append([]byte(nil), append(serverKeyS1, randomCrud...)...)
|
|
)
|
|
|
|
// C2S2 is a C2 or S2 packet.
|
|
type C2S2 struct {
|
|
Time uint32
|
|
Time2 uint32
|
|
Data []byte
|
|
}
|
|
|
|
// Read reads a C2S2.
|
|
func (c *C2S2) Read(r io.Reader) error {
|
|
buf := make([]byte, c2s2Size)
|
|
_, err := io.ReadFull(r, buf)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
c.Time = uint32(buf[0])<<24 | uint32(buf[1])<<16 | uint32(buf[2])<<8 | uint32(buf[3])
|
|
c.Time2 = uint32(buf[4])<<24 | uint32(buf[5])<<16 | uint32(buf[6])<<8 | uint32(buf[7])
|
|
c.Data = buf[8:]
|
|
|
|
return nil
|
|
}
|
|
|
|
func (c C2S2) computeDigest(isS2 bool, prevDigest []byte) []byte {
|
|
// hash entire message except digest
|
|
msg := make([]byte, c2s2Size-digestLength)
|
|
msg[0] = byte(c.Time >> 24)
|
|
msg[1] = byte(c.Time >> 16)
|
|
msg[2] = byte(c.Time >> 8)
|
|
msg[3] = byte(c.Time)
|
|
msg[4] = byte(c.Time2 >> 24)
|
|
msg[5] = byte(c.Time2 >> 16)
|
|
msg[6] = byte(c.Time2 >> 8)
|
|
msg[7] = byte(c.Time2)
|
|
copy(msg[8:], c.Data[:c2s2DigestPos])
|
|
|
|
var key []byte
|
|
if isS2 {
|
|
key = hmacSha256(serverKeyS2, prevDigest)
|
|
} else {
|
|
key = hmacSha256(clientKeyC2, prevDigest)
|
|
}
|
|
|
|
return hmacSha256(key, msg)
|
|
}
|
|
|
|
func (c C2S2) validate(isS2 bool, prevDigest []byte) error {
|
|
d1 := c.Data[c2s2DigestPos : c2s2DigestPos+digestLength]
|
|
d2 := c.computeDigest(isS2, prevDigest)
|
|
|
|
if !bytes.Equal(d1, d2) {
|
|
return fmt.Errorf("unable to validate C2/S2 digest")
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (c *C2S2) fillPlain() error {
|
|
c.Data = make([]byte, c2s2Size-8)
|
|
_, err := rand.Read(c.Data)
|
|
return err
|
|
}
|
|
|
|
func (c *C2S2) fill(isS2 bool, prevDigest []byte) error {
|
|
err := c.fillPlain()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
digest := c.computeDigest(isS2, prevDigest)
|
|
copy(c.Data[c2s2DigestPos:], digest)
|
|
return nil
|
|
}
|
|
|
|
// Write writes a C2S2.
|
|
func (c C2S2) Write(w io.Writer) error {
|
|
buf := make([]byte, c2s2Size)
|
|
|
|
buf[0] = byte(c.Time >> 24)
|
|
buf[1] = byte(c.Time >> 16)
|
|
buf[2] = byte(c.Time >> 8)
|
|
buf[3] = byte(c.Time)
|
|
buf[4] = byte(c.Time2 >> 24)
|
|
buf[5] = byte(c.Time2 >> 16)
|
|
buf[6] = byte(c.Time2 >> 8)
|
|
buf[7] = byte(c.Time2)
|
|
copy(buf[8:], c.Data)
|
|
|
|
_, err := w.Write(buf)
|
|
return err
|
|
}
|