edge/pkg/module/auth/http/passwd/argon2id/hasher.go

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package argon2id
import (
"crypto/rand"
"crypto/subtle"
"encoding/base64"
"fmt"
"strings"
"forge.cadoles.com/arcad/edge/pkg/module/auth/http/passwd"
"github.com/pkg/errors"
"golang.org/x/crypto/argon2"
)
const (
Algo passwd.Algo = "argon2id"
)
func init() {
passwd.Register(Algo, &Hasher{})
}
var (
ErrInvalidHash = errors.New("invalid hash")
ErrIncompatibleVersion = errors.New("incompatible version")
)
type params struct {
memory uint32
iterations uint32
parallelism uint8
saltLength uint32
keyLength uint32
}
var defaultParams = params{
memory: 64 * 1024,
iterations: 3,
parallelism: 2,
saltLength: 16,
keyLength: 32,
}
type Hasher struct{}
// Hash implements passwd.Hasher
func (*Hasher) Hash(plaintext string) (string, error) {
salt, err := generateRandomBytes(defaultParams.saltLength)
if err != nil {
return "", errors.WithStack(err)
}
hash := argon2.IDKey([]byte(plaintext), salt, defaultParams.iterations, defaultParams.memory, defaultParams.parallelism, defaultParams.keyLength)
// Base64 encode the salt and hashed password.
b64Salt := base64.RawStdEncoding.EncodeToString(salt)
b64Hash := base64.RawStdEncoding.EncodeToString(hash)
// Return a string using the standard encoded hash representation.
encodedHash := fmt.Sprintf("$argon2id$v=%d$m=%d,t=%d,p=%d$%s$%s", argon2.Version, defaultParams.memory, defaultParams.iterations, defaultParams.parallelism, b64Salt, b64Hash)
return encodedHash, nil
}
// Match implements passwd.Hasher.
func (*Hasher) Match(plaintext string, hash string) (bool, error) {
matches, err := comparePasswordAndHash(plaintext, hash)
if err != nil {
return false, errors.WithStack(err)
}
return matches, nil
}
var _ passwd.Hasher = &Hasher{}
func generateRandomBytes(n uint32) ([]byte, error) {
buf := make([]byte, n)
if _, err := rand.Read(buf); err != nil {
return nil, errors.WithStack(err)
}
return buf, nil
}
func comparePasswordAndHash(password, encodedHash string) (match bool, err error) {
p, salt, hash, err := decodeHash(encodedHash)
if err != nil {
return false, errors.WithStack(err)
}
otherHash := argon2.IDKey([]byte(password), salt, p.iterations, p.memory, p.parallelism, p.keyLength)
if subtle.ConstantTimeCompare(hash, otherHash) == 1 {
return true, nil
}
return false, nil
}
func decodeHash(encodedHash string) (p *params, salt, hash []byte, err error) {
vals := strings.Split(encodedHash, "$")
if len(vals) != 6 {
return nil, nil, nil, ErrInvalidHash
}
var version int
_, err = fmt.Sscanf(vals[2], "v=%d", &version)
if err != nil {
return nil, nil, nil, err
}
if version != argon2.Version {
return nil, nil, nil, ErrIncompatibleVersion
}
p = &params{}
_, err = fmt.Sscanf(vals[3], "m=%d,t=%d,p=%d", &p.memory, &p.iterations, &p.parallelism)
if err != nil {
return nil, nil, nil, err
}
salt, err = base64.RawStdEncoding.Strict().DecodeString(vals[4])
if err != nil {
return nil, nil, nil, err
}
p.saltLength = uint32(len(salt))
hash, err = base64.RawStdEncoding.Strict().DecodeString(vals[5])
if err != nil {
return nil, nil, nil, err
}
p.keyLength = uint32(len(hash))
return p, salt, hash, nil
}