mirror of
https://codeberg.org/cunicu/cunicu.git
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170 lines
3.2 KiB
Go
170 lines
3.2 KiB
Go
package crypto
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import (
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"crypto/hmac"
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"crypto/sha512"
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"encoding/base64"
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"errors"
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"net"
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"github.com/aead/siphash"
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"github.com/pion/dtls/v2/pkg/crypto/hash"
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"golang.org/x/crypto/curve25519"
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"golang.org/x/crypto/pbkdf2"
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"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
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)
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// Keys
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const (
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KeyLength = 32
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SignatureLength = 64
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pbkdf2Iterations = 4096
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)
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var (
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// A ɯice specific key for siphash to generate unique IPv6 addresses from the
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// interfaces public key
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addrHashKey = [...]byte{0x67, 0x67, 0x2c, 0x05, 0xd1, 0x3e, 0x11, 0x94, 0xbb, 0x38, 0x91, 0xff, 0x4f, 0x80, 0xb3, 0x97}
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pbkdf2Salt = [...]byte{0x77, 0x31, 0x63, 0x33, 0x63, 0x30, 0x6e, 0x6e, 0x33, 0x63, 0x74, 0x73, 0x33, 0x76, 0x65, 0x72, 0x79, 0x62, 0x30, 0x64, 0x79}
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)
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type Nonce []byte
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type Key [KeyLength]byte
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type Signature [SignatureLength]byte
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func GenerateKeyFromPassword(pw string) Key {
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key := pbkdf2.Key([]byte(pw), pbkdf2Salt[:], pbkdf2Iterations, KeyLength, sha512.New)
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// Modify random bytes using algorithm described at:
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// https://cr.yp.to/ecdh.html.
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key[0] &= 248
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key[31] &= 127
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key[31] |= 64
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return *(*Key)(key)
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}
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func GenerateKey() (Key, error) {
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key, err := wgtypes.GenerateKey()
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if err != nil {
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return Key{}, err
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}
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return Key(key), nil
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}
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func GeneratePrivateKey() (Key, error) {
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key, err := wgtypes.GeneratePrivateKey()
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if err != nil {
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return Key{}, err
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}
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return Key(key), nil
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}
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func ParseKey(str string) (Key, error) {
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k, err := base64.StdEncoding.DecodeString(str)
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if err != nil {
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return Key{}, err
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}
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var key Key
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copy(key[:], k[:KeyLength])
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return key, nil
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}
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func ParseKeyBytes(buf []byte) (Key, error) {
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if len(buf) != KeyLength {
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return Key{}, errors.New("invalid length")
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}
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return *(*Key)(buf), nil
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}
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func (k Key) String() string {
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return base64.StdEncoding.EncodeToString(k[:])
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}
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func (k Key) MarshalText() ([]byte, error) {
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return []byte(k.String()), nil
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}
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func (k *Key) UnmarshalText(text []byte) error {
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var err error
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*k, err = ParseKey(string(text))
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return err
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}
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func (k Key) PublicKey() Key {
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key := wgtypes.Key(k)
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return Key(key.PublicKey())
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}
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func (k Key) Bytes() []byte {
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return k[:]
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}
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// IPv6Address derives an IPv6 link local address from they key
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func (k Key) IPv6Address() *net.IPNet {
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ip := net.IP{0xfe, 0x80, 0, 0, 0, 0, 0, 0}
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hash, _ := siphash.New64(addrHashKey[:])
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hash.Write(k[:])
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// Append interface identifier from the hash function
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ip = hash.Sum(ip)
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return &net.IPNet{
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IP: ip,
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Mask: net.CIDRMask(64, 128),
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}
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}
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// Checks if the key is not zero
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func (k Key) IsSet() bool {
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return k != Key{}
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}
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func (k Signature) String() string {
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return base64.StdEncoding.EncodeToString(k[:])
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}
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type KeyPair struct {
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Ours Key `json:"ours"`
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Theirs Key `json:"theirs"`
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}
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type PublicKeyPair KeyPair
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func (kp KeyPair) ID(key []byte) string {
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if key == nil {
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key = []byte{}
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}
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ctx := hmac.New(hash.SHA512.CryptoHash().HashFunc().New, key)
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ctx.Write(kp.Ours[:])
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ctx.Write(kp.Theirs[:])
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mac := ctx.Sum(nil)
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return base64.URLEncoding.EncodeToString(mac)
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}
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func (kp KeyPair) Shared() Key {
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shared, _ := curve25519.X25519(kp.Ours[:], kp.Theirs[:])
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return *(*Key)(shared)
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}
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func (kp KeyPair) Public() PublicKeyPair {
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return PublicKeyPair{
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Ours: kp.Ours.PublicKey(),
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Theirs: kp.Theirs,
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}
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}
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