/
argon2.go
231 lines (202 loc) · 4.78 KB
/
argon2.go
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package argon2
import (
"bytes"
"crypto/rand"
"crypto/subtle"
"encoding/base64"
"fmt"
"strconv"
"golang.org/x/crypto/argon2"
"go.sour.is/passwd"
)
type argon struct {
version uint8
time uint32
memory uint32
threads uint8
keyLen uint32
saltLen uint32
name string
keyFn func(password, salt []byte, time, memory uint32, threads uint8, keyLen uint32) []byte
}
var All = []passwd.Passwder{Argon2i, Argon2id}
// Argon2i sets default recommended values.
var Argon2i = NewArgon2i(3, 32*1024, 4, 32, 16)
// Argon2id sets default recommended values.
var Argon2id = NewArgon2id(1, 64*1024, 4, 32, 16)
// NewArgon2i creates a new
func NewArgon2i(
time uint32,
memory uint32,
threads uint8,
keyLen uint32,
saltLen uint32,
) *argon {
return &argon{
version: argon2.Version,
time: time,
memory: memory,
threads: threads,
keyLen: keyLen,
saltLen: saltLen,
name: "argon2i",
keyFn: argon2.Key,
}
}
// NewArgon2i creates a new
func NewArgon2id(
time uint32,
memory uint32,
threads uint8,
keyLen uint32,
saltLen uint32,
) *argon {
return &argon{
version: argon2.Version,
time: time,
memory: memory,
threads: threads,
keyLen: keyLen,
saltLen: saltLen,
name: "argon2id",
keyFn: argon2.IDKey,
}
}
func (p *argon) Passwd(pass, check []byte) ([]byte, error) {
var args *pwArgs
var err error
if check == nil {
args = p.defaultArgs()
_, err := rand.Read(args.salt)
if err != nil {
return nil, err
}
args.hash = p.keyFn(pass, args.salt, args.time, args.memory, args.threads, args.keyLen)
} else {
args, err = p.parseArgs(check)
if err != nil {
return nil, err
}
hash := p.keyFn(pass, args.salt, args.time, args.memory, args.threads, args.keyLen)
if subtle.ConstantTimeCompare(hash, args.hash) == 0 {
return nil, passwd.ErrNoMatch
}
}
return args.Bytes(), nil
}
func (p *argon) ApplyPasswd(passwd *passwd.Passwd) {
passwd.Register(p.name, p)
}
func (s *argon) IsPreferred(hash []byte) bool {
args, err := s.parseArgs(hash)
if err != nil {
return false
}
if args.version < s.version {
return false
}
if args.time < s.time {
return false
}
if args.memory < s.memory {
return false
}
if args.threads < s.threads {
return false
}
if args.keyLen < s.keyLen {
return false
}
if len(args.salt) < int(s.saltLen) {
return false
}
if len(args.hash) < int(s.keyLen) {
return false
}
return true
}
func (p *argon) defaultArgs() *pwArgs {
return &pwArgs{
name: p.name,
version: p.version,
time: p.time,
memory: p.memory,
threads: p.threads,
keyLen: p.keyLen,
salt: make([]byte, p.saltLen),
}
}
func (p *argon) parseArgs(hash []byte) (*pwArgs, error) {
pfx := []byte("$" + p.name + "$")
if !bytes.HasPrefix(hash, pfx) {
return nil, fmt.Errorf("%w: missing prefix", passwd.ErrBadHash)
}
hash = bytes.TrimPrefix(hash, pfx)
args, hash, ok := bytes.Cut(hash, []byte("$"))
if !ok {
return nil, fmt.Errorf("%w: missing args", passwd.ErrBadHash)
}
salt, hash, ok := bytes.Cut(hash, []byte("$"))
if !ok {
return nil, fmt.Errorf("%w: missing salt", passwd.ErrBadHash)
}
var err error
pass := p.defaultArgs()
pass.salt = make([]byte, base64.RawStdEncoding.DecodedLen(len(salt)))
_, err = base64.RawStdEncoding.Decode(pass.salt, salt)
if err != nil {
return nil, fmt.Errorf("%w: corrupt salt part", passwd.ErrBadHash)
}
pass.hash = make([]byte, base64.RawStdEncoding.DecodedLen(len(hash)))
_, err = base64.RawStdEncoding.Decode(pass.hash, hash)
if err != nil {
return nil, fmt.Errorf("%w: corrupt hash part", passwd.ErrBadHash)
}
pass.name = p.name
pass.keyLen = uint32(len(pass.hash))
for _, part := range bytes.Split(args, []byte(",")) {
if k, v, ok := bytes.Cut(part, []byte("=")); ok {
switch string(k) {
case "v":
if i, err := strconv.ParseUint(string(v), 10, 8); err == nil {
pass.version = uint8(i)
}
case "m":
if i, err := strconv.ParseUint(string(v), 10, 32); err == nil {
pass.memory = uint32(i)
}
case "t":
if i, err := strconv.ParseUint(string(v), 10, 32); err == nil {
pass.time = uint32(i)
}
case "p":
if i, err := strconv.ParseUint(string(v), 10, 8); err == nil {
pass.threads = uint8(i)
}
}
}
}
return pass, nil
}
type pwArgs struct {
name string
version uint8
time uint32
memory uint32
threads uint8
keyLen uint32
salt []byte
hash []byte
}
func (p *pwArgs) Bytes() []byte {
var b bytes.Buffer
fmt.Fprintf(&b, "$%s$v=%d,m=%d,t=%d,p=%d$", p.name, p.version, p.memory, p.time, p.threads)
salt := make([]byte, base64.RawURLEncoding.EncodedLen(len(p.salt)))
base64.RawStdEncoding.Encode(salt, p.salt)
b.Write(salt)
hash := make([]byte, base64.RawURLEncoding.EncodedLen(len(p.hash)))
base64.RawStdEncoding.Encode(hash, p.hash)
b.WriteRune('$')
b.Write(hash)
return b.Bytes()
}