2 GoVPN -- simple secure free software virtual private network daemon
3 Copyright (C) 2014-2020 Sergey Matveev <stargrave@stargrave.org>
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation, version 3 of the License.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>.
31 "github.com/agl/ed25519"
32 "go.cypherpunks.ru/balloon"
33 "golang.org/x/crypto/blake2b"
34 "golang.org/x/crypto/ssh/terminal"
38 DefaultS = 1 << 20 / 32
43 type Verifier struct {
48 Pub *[ed25519.PublicKeySize]byte
51 // Generate new verifier for given peer, with specified password and
52 // hashing parameters.
53 func VerifierNew(s, t, p int, id *PeerID) *Verifier {
54 return &Verifier{S: s, T: t, P: p, ID: id}
57 func blake2bKeyless() hash.Hash {
58 h, err := blake2b.New256(nil)
65 // Apply the password: create Ed25519 keypair based on it, save public
67 func (v *Verifier) PasswordApply(password string) *[ed25519.PrivateKeySize]byte {
68 r := balloon.H(blake2bKeyless, []byte(password), v.ID[:], v.S, v.T, v.P)
70 src := bytes.NewBuffer(r)
71 pub, prv, err := ed25519.GenerateKey(src)
73 log.Fatalln("Unable to generate Ed25519 keypair", err)
79 // Parse either short or long verifier form.
80 func VerifierFromString(input string) (*Verifier, error) {
81 ss := strings.Split(input, "$")
82 if len(ss) < 4 || ss[1] != "balloon" {
83 return nil, errors.New("Invalid verifier structure")
86 n, err := fmt.Sscanf(ss[2], "s=%d,t=%d,p=%d", &s, &t, &p)
87 if n != 3 || err != nil {
88 return nil, errors.New("Invalid verifier parameters")
90 salt, err := base64.RawStdEncoding.DecodeString(ss[3])
94 v := Verifier{S: s, T: t, P: p}
95 id := new([IDSize]byte)
100 pub, err := base64.RawStdEncoding.DecodeString(ss[4])
104 v.Pub = new([ed25519.PublicKeySize]byte)
110 // Short verifier string form -- it is useful for the client.
111 // Does not include public key.
112 func (v *Verifier) ShortForm() string {
114 "$balloon$s=%d,t=%d,p=%d$%s",
115 v.S, v.T, v.P, base64.RawStdEncoding.EncodeToString(v.ID[:]),
119 // Long verifier string form -- it is useful for the server.
120 // Includes public key.
121 func (v *Verifier) LongForm() string {
123 "%s$%s", v.ShortForm(),
124 base64.RawStdEncoding.EncodeToString(v.Pub[:]),
128 // Read the key either from text file (if path is specified), or
129 // from the terminal.
130 func KeyRead(path string) (string, error) {
135 os.Stderr.WriteString("Passphrase:")
136 p, err = terminal.ReadPassword(0)
137 os.Stderr.WriteString("\n")
140 p, err = ioutil.ReadFile(path)
141 pass = strings.TrimRight(string(p), "\n")
147 return "", errors.New("Empty passphrase submitted")