forked from alterminal/alterminal
111 lines
3.6 KiB
Go
111 lines
3.6 KiB
Go
package auth
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import (
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"crypto/rand"
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"crypto/subtle"
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"encoding/base64"
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"errors"
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"fmt"
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"strings"
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"time"
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"golang.org/x/crypto/argon2"
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)
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// Role 為使用者角色：admin 具管理權限，user 為一般權限。
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type Role string
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// 允許的角色值。
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const (
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RoleAdmin Role = "admin"
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RoleUser Role = "user"
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)
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// Valid 回傳角色是否為允許的值。
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func (r Role) Valid() bool {
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return r == RoleAdmin || r == RoleUser
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}
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// User 為使用者帳號模型，對應 users 資料表。
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// Username 與 Email 皆為唯一；密碼以 argon2id（PHC 格式）雜湊儲存，永不存明文。
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type User struct {
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ID uint `gorm:"primaryKey"`
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Username string `gorm:"uniqueIndex;size:64;not null"` // 登入帳號
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Email string `gorm:"uniqueIndex;size:255;not null"` // OIDC email scope
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EmailVerified bool `gorm:"not null;default:false"` // OIDC email_verified claim
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PasswordHash string `gorm:"size:255;not null"` // argon2id PHC 字串
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Name string `gorm:"size:255"` // 顯示名稱（profile scope 的 name claim）
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Role Role `gorm:"size:16;not null;default:user"` // admin 或 user
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CreatedAt time.Time
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UpdatedAt time.Time
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}
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// SetPassword 以 argon2id 雜湊密碼並寫入 PasswordHash。
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func (u *User) SetPassword(password string) error {
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hash, err := HashPassword(password)
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if err != nil {
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return err
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}
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u.PasswordHash = hash
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return nil
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}
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// CheckPassword 回傳密碼是否與 PasswordHash 相符；雜湊格式無效時一律視為不相符。
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func (u *User) CheckPassword(password string) bool {
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ok, err := VerifyPassword(password, u.PasswordHash)
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return err == nil && ok
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}
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// 參數採 OWASP 對 Argon2id 的建議：m=19 MiB、t=2、p=1，salt 16 bytes、key 32 bytes。
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const (
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argon2MemoryKB = 19 * 1024
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argon2Time = 2
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argon2Threads = 1
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argon2SaltLen = 16
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argon2KeyLen = 32
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)
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// HashPassword 產生格式如 $argon2id$v=19$m=19456,t=2,p=1$<salt>$<key> 的 PHC 字串。
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func HashPassword(password string) (string, error) {
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salt := make([]byte, argon2SaltLen)
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if _, err := rand.Read(salt); err != nil {
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return "", fmt.Errorf("read salt: %w", err)
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}
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key := argon2.IDKey([]byte(password), salt, argon2Time, argon2MemoryKB, argon2Threads, argon2KeyLen)
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return fmt.Sprintf("$argon2id$v=%d$m=%d,t=%d,p=%d$%s$%s",
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argon2.Version, argon2MemoryKB, argon2Time, argon2Threads,
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base64.RawStdEncoding.EncodeToString(salt),
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base64.RawStdEncoding.EncodeToString(key),
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), nil
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}
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// VerifyPassword 解析 PHC 字串並以 constant-time 比對重算結果。
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func VerifyPassword(password, encoded string) (bool, error) {
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parts := strings.Split(encoded, "$")
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if len(parts) != 6 || parts[1] != "argon2id" {
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return false, errors.New("malformed password hash")
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}
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var version int
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if _, err := fmt.Sscanf(parts[2], "v=%d", &version); err != nil {
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return false, fmt.Errorf("parse version: %w", err)
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}
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if version != argon2.Version {
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return false, fmt.Errorf("unsupported argon2id version %d", version)
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}
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var memoryKB, timeCost uint32
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var threads uint8
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if _, err := fmt.Sscanf(parts[3], "m=%d,t=%d,p=%d", &memoryKB, &timeCost, &threads); err != nil {
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return false, fmt.Errorf("parse parameters: %w", err)
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}
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salt, err := base64.RawStdEncoding.DecodeString(parts[4])
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if err != nil {
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return false, fmt.Errorf("decode salt: %w", err)
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}
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want, err := base64.RawStdEncoding.DecodeString(parts[5])
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if err != nil {
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return false, fmt.Errorf("decode key: %w", err)
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}
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got := argon2.IDKey([]byte(password), salt, timeCost, memoryKB, threads, uint32(len(want)))
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return subtle.ConstantTimeCompare(got, want) == 1, nil
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}
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