Files
eng-pad-server/internal/auth/argon2.go
Kyle Isom 286b886c06 Implement Phase 2: password auth (Argon2id + bearer tokens)
- Argon2id password hashing and verification with configurable params
- Bearer token generation (32-byte random), SHA-256 hashed storage,
  TTL-based expiry
- User creation and authentication helpers
- auth_tokens table added to migrations
- 6 tests: hash/verify, wrong password, create/auth user, token
  create/validate, token expiry

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-03-24 19:49:07 -07:00

78 lines
1.9 KiB
Go

package auth
import (
"crypto/rand"
"crypto/subtle"
"encoding/base64"
"fmt"
"strings"
"golang.org/x/crypto/argon2"
)
type Argon2Params struct {
Memory uint32
Time uint32
Threads uint8
}
var DefaultParams = Argon2Params{
Memory: 65536,
Time: 3,
Threads: 4,
}
const saltLen = 16
const keyLen = 32
// HashPassword generates an Argon2id hash string.
func HashPassword(password string, params Argon2Params) (string, error) {
salt := make([]byte, saltLen)
if _, err := rand.Read(salt); err != nil {
return "", fmt.Errorf("generate salt: %w", err)
}
key := argon2.IDKey([]byte(password), salt, params.Time, params.Memory, params.Threads, keyLen)
return fmt.Sprintf("$argon2id$v=%d$m=%d,t=%d,p=%d$%s$%s",
argon2.Version,
params.Memory, params.Time, params.Threads,
base64.RawStdEncoding.EncodeToString(salt),
base64.RawStdEncoding.EncodeToString(key),
), nil
}
// VerifyPassword checks a password against an Argon2id hash string.
func VerifyPassword(password, hash string) (bool, error) {
parts := strings.Split(hash, "$")
if len(parts) != 6 || parts[1] != "argon2id" {
return false, fmt.Errorf("invalid hash format")
}
var v int
if _, err := fmt.Sscanf(parts[2], "v=%d", &v); err != nil {
return false, fmt.Errorf("parse version: %w", err)
}
var memory uint32
var time uint32
var threads uint8
if _, err := fmt.Sscanf(parts[3], "m=%d,t=%d,p=%d", &memory, &time, &threads); err != nil {
return false, fmt.Errorf("parse params: %w", err)
}
salt, err := base64.RawStdEncoding.DecodeString(parts[4])
if err != nil {
return false, fmt.Errorf("decode salt: %w", err)
}
expectedKey, err := base64.RawStdEncoding.DecodeString(parts[5])
if err != nil {
return false, fmt.Errorf("decode key: %w", err)
}
key := argon2.IDKey([]byte(password), salt, time, memory, threads, uint32(len(expectedKey)))
return subtle.ConstantTimeCompare(key, expectedKey) == 1, nil
}