mirror of
https://github.com/bluenviron/mediamtx
synced 2025-02-13 09:58:50 +00:00
119 lines
2.9 KiB
Go
119 lines
2.9 KiB
Go
package handshake
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import (
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"crypto/rand"
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"fmt"
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"math/big"
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)
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const (
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dhKeyLength = 128
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)
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var (
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p1024 = []byte{
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xc9, 0x0f, 0xda, 0xa2, 0x21, 0x68, 0xc2, 0x34,
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0xc4, 0xc6, 0x62, 0x8b, 0x80, 0xdc, 0x1c, 0xd1,
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0x29, 0x02, 0x4e, 0x08, 0x8a, 0x67, 0xcc, 0x74,
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0x02, 0x0b, 0xbe, 0xa6, 0x3b, 0x13, 0x9b, 0x22,
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0x51, 0x4a, 0x08, 0x79, 0x8e, 0x34, 0x04, 0xdd,
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0xef, 0x95, 0x19, 0xb3, 0xcd, 0x3a, 0x43, 0x1b,
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0x30, 0x2b, 0x0a, 0x6d, 0xf2, 0x5f, 0x14, 0x37,
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0x4f, 0xe1, 0x35, 0x6d, 0x6d, 0x51, 0xc2, 0x45,
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0xe4, 0x85, 0xb5, 0x76, 0x62, 0x5e, 0x7e, 0xc6,
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0xf4, 0x4c, 0x42, 0xe9, 0xa6, 0x37, 0xed, 0x6b,
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0x0b, 0xff, 0x5c, 0xb6, 0xf4, 0x06, 0xb7, 0xed,
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0xee, 0x38, 0x6b, 0xfb, 0x5a, 0x89, 0x9f, 0xa5,
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0xae, 0x9f, 0x24, 0x11, 0x7c, 0x4b, 0x1f, 0xe6,
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0x49, 0x28, 0x66, 0x51, 0xec, 0xe6, 0x53, 0x81,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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}
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q1024 = []byte{
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0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xe4, 0x87, 0xed, 0x51, 0x10, 0xb4, 0x61, 0x1a,
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0x62, 0x63, 0x31, 0x45, 0xc0, 0x6e, 0x0e, 0x68,
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0x94, 0x81, 0x27, 0x04, 0x45, 0x33, 0xe6, 0x3a,
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0x01, 0x05, 0xdf, 0x53, 0x1d, 0x89, 0xcd, 0x91,
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0x28, 0xa5, 0x04, 0x3c, 0xc7, 0x1a, 0x02, 0x6e,
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0xf7, 0xca, 0x8c, 0xd9, 0xe6, 0x9d, 0x21, 0x8d,
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0x98, 0x15, 0x85, 0x36, 0xf9, 0x2f, 0x8a, 0x1b,
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0xa7, 0xf0, 0x9a, 0xb6, 0xb6, 0xa8, 0xe1, 0x22,
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0xf2, 0x42, 0xda, 0xbb, 0x31, 0x2f, 0x3f, 0x63,
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0x7a, 0x26, 0x21, 0x74, 0xd3, 0x1b, 0xf6, 0xb5,
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0x85, 0xff, 0xae, 0x5b, 0x7a, 0x03, 0x5b, 0xf6,
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0xf7, 0x1c, 0x35, 0xfd, 0xad, 0x44, 0xcf, 0xd2,
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0xd7, 0x4f, 0x92, 0x08, 0xbe, 0x25, 0x8f, 0xf3,
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0x24, 0x94, 0x33, 0x28, 0xf6, 0x73, 0x29, 0xc0,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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}
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)
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// https://datatracker.ietf.org/doc/html/rfc2631#section-2.1.5
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func dhValidatePublicKey(key []byte) error {
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// 1. y >= 2 && y < p
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var y big.Int
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y.SetBytes(key)
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var two big.Int
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two.SetUint64(2)
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r := y.Cmp(&two)
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if r < 0 {
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return fmt.Errorf("key is < 2")
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}
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var p big.Int
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p.SetBytes(p1024)
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r = y.Cmp(&p)
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if r >= 0 {
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return fmt.Errorf("key is >= p")
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}
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// 2. (y^q mod p) == 1
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var q big.Int
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q.SetBytes(q1024)
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var z big.Int
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z.Exp(&y, &q, &p)
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var one big.Int
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one.SetUint64(1)
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r = z.Cmp(&one)
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if r != 0 {
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return fmt.Errorf("y^q mod p is != 1")
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}
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return nil
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}
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func dhGenerateKeyPair() ([]byte, []byte, error) {
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priv := make([]byte, dhKeyLength)
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_, err := rand.Read(priv)
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if err != nil {
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return nil, nil, err
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}
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// y = g ^ x mod p
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var g big.Int
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g.SetUint64(2)
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var x big.Int
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x.SetBytes(priv)
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var p big.Int
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p.SetBytes(p1024)
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var y big.Int
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y.Exp(&g, &x, &p)
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pub := y.Bytes()
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return priv, pub, nil
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}
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// https://datatracker.ietf.org/doc/html/rfc2631#section-2.1.1
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func dhComputeSharedSecret(priv []byte, pub []byte) []byte {
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// ZZ = (ya ^ xb) mod p
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var y big.Int
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y.SetBytes(pub)
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var x big.Int
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x.SetBytes(priv)
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var p big.Int
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p.SetBytes(p1024)
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var z big.Int
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z.Exp(&y, &x, &p)
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return z.Bytes()
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}
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