--- /dev/null
+/*
+GoVPN -- simple secure free software virtual private network daemon
+Copyright (C) 2014-2016 Sergey Matveev <stargrave@stargrave.org>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package govpn
+
+import (
+ "bytes"
+ "encoding/base64"
+ "errors"
+ "fmt"
+ "io/ioutil"
+ "log"
+ "strings"
+
+ "github.com/agl/ed25519"
+ "github.com/magical/argon2"
+ "golang.org/x/crypto/ssh/terminal"
+)
+
+const (
+ DefaultM = 1 << 12
+ DefaultT = 1 << 7
+ DefaultP = 1
+)
+
+type Verifier struct {
+ M int
+ T int
+ P int
+ Id *PeerId
+ Pub *[ed25519.PublicKeySize]byte
+}
+
+// Generate new verifier for given peer, with specified password and
+// hashing parameters.
+func VerifierNew(m, t, p int, id *PeerId) *Verifier {
+ return &Verifier{M: m, T: t, P: p, Id: id}
+}
+
+// Apply the password: create Ed25519 keypair based on it, save public
+// key in verifier.
+func (v *Verifier) PasswordApply(password string) *[ed25519.PrivateKeySize]byte {
+ r, err := argon2.Key([]byte(password), v.Id[:], v.T, v.P, int64(v.M), 32)
+ if err != nil {
+ log.Fatalln("Unable to apply Argon2d", err)
+ }
+ defer SliceZero(r)
+ src := bytes.NewBuffer(r)
+ pub, prv, err := ed25519.GenerateKey(src)
+ if err != nil {
+ log.Fatalln("Unable to generate Ed25519 keypair", err)
+ }
+ v.Pub = pub
+ return prv
+}
+
+// Parse either short or long verifier form.
+func VerifierFromString(input string) (*Verifier, error) {
+ s := strings.Split(input, "$")
+ if !(len(s) != 4 || len(s) != 5) || s[1] != "argon2d" {
+ return nil, errors.New("Invalid verifier structure")
+ }
+ var m, t, p int
+ n, err := fmt.Sscanf(s[2], "m=%d,t=%d,p=%d", &m, &t, &p)
+ if n != 3 || err != nil {
+ return nil, errors.New("Invalid verifier parameters")
+ }
+ salt, err := base64.RawStdEncoding.DecodeString(s[3])
+ if err != nil {
+ return nil, err
+ }
+ v := Verifier{M: m, T: t, P: p}
+ id := new([IDSize]byte)
+ copy(id[:], salt)
+ pid := PeerId(*id)
+ v.Id = &pid
+ if len(s) == 5 {
+ pub, err := base64.RawStdEncoding.DecodeString(s[4])
+ if err != nil {
+ return nil, err
+ }
+ v.Pub = new([ed25519.PublicKeySize]byte)
+ copy(v.Pub[:], pub)
+ }
+ return &v, nil
+}
+
+// Short verifier string form -- it is useful for the client.
+// Does not include public key.
+func (v *Verifier) ShortForm() string {
+ return fmt.Sprintf(
+ "$argon2d$m=%d,t=%d,p=%d$%s",
+ v.M, v.T, v.P, base64.RawStdEncoding.EncodeToString(v.Id[:]),
+ )
+}
+
+// Long verifier string form -- it is useful for the server.
+// Includes public key.
+func (v *Verifier) LongForm() string {
+ return fmt.Sprintf(
+ "%s$%s", v.ShortForm(),
+ base64.RawStdEncoding.EncodeToString(v.Pub[:]),
+ )
+}
+
+// Read the key either from text file (if path is specified), or
+// from the terminal.
+func KeyRead(path string) (string, error) {
+ var p []byte
+ var err error
+ var pass string
+ if path == "" {
+ fmt.Print("Passphrase:")
+ p, err = terminal.ReadPassword(0)
+ fmt.Print("\n")
+ pass = string(p)
+ } else {
+ p, err = ioutil.ReadFile(path)
+ pass = strings.TrimRight(string(p), "\n")
+ }
+ if err != nil {
+ return "", err
+ }
+ if len(pass) == 0 {
+ return "", errors.New("Empty passphrase submitted")
+ }
+ return pass, err
+}