145 lines
3.4 KiB
Go
145 lines
3.4 KiB
Go
// FILE: auth/argon2.go
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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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"fmt"
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"strings"
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"golang.org/x/crypto/argon2"
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)
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// Default Argon2id parameters
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const (
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DefaultArgonTime = 3 // iterations
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DefaultArgonMemory = 64 * 1024 // 64 MB
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DefaultArgonThreads = 4
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DefaultArgonSaltLen = 16
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DefaultArgonKeyLen = 32
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)
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// argonParams holds configurable Argon2id parameters
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type argonParams struct {
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time uint32
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memory uint32
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threads uint8
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keyLen uint32
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saltLen uint32
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}
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// Option configures Argon2id hashing parameters
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type Option func(*argonParams)
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// WithTime sets Argon2 iterations
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func WithTime(t uint32) Option {
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return func(p *argonParams) {
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if t > 0 {
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p.time = t
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}
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}
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}
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// WithMemory sets Argon2 memory in KiB
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func WithMemory(m uint32) Option {
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return func(p *argonParams) {
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if m > 0 {
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p.memory = m
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}
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}
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}
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// WithThreads sets Argon2 parallelism
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func WithThreads(t uint8) Option {
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return func(p *argonParams) {
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if t > 0 {
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p.threads = t
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}
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}
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}
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// HashPassword creates Argon2id PHC-format hash (standalone)
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func HashPassword(password string, opts ...Option) (string, error) {
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if len(password) < 8 {
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return "", ErrWeakPassword
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}
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params := &argonParams{
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time: DefaultArgonTime,
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memory: DefaultArgonMemory,
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threads: DefaultArgonThreads,
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keyLen: DefaultArgonKeyLen,
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saltLen: DefaultArgonSaltLen,
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}
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for _, opt := range opts {
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opt(params)
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}
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salt := make([]byte, params.saltLen)
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if _, err := rand.Read(salt); err != nil {
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return "", fmt.Errorf("%w: %v", ErrSaltGenerationFailed, err)
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}
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hash := argon2.IDKey([]byte(password), salt, params.time, params.memory, params.threads, params.keyLen)
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saltB64 := base64.RawStdEncoding.EncodeToString(salt)
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hashB64 := base64.RawStdEncoding.EncodeToString(hash)
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return fmt.Sprintf("$argon2id$v=%d$m=%d,t=%d,p=%d$%s$%s",
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argon2.Version, params.memory, params.time, params.threads, saltB64, hashB64), nil
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}
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// VerifyPassword checks password against PHC-format hash (standalone)
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func VerifyPassword(password, phcHash string) error {
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parts := strings.Split(phcHash, "$")
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if len(parts) != 6 || parts[1] != "argon2id" {
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return ErrPHCInvalidFormat
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}
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var memory, time uint32
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var threads uint8
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fmt.Sscanf(parts[3], "m=%d,t=%d,p=%d", &memory, &time, &threads)
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salt, err := base64.RawStdEncoding.DecodeString(parts[4])
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if err != nil {
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return fmt.Errorf("%w: %v", ErrPHCInvalidSalt, err)
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}
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expectedHash, err := base64.RawStdEncoding.DecodeString(parts[5])
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if err != nil {
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return fmt.Errorf("%w: %v", ErrPHCInvalidHash, err)
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}
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computedHash := argon2.IDKey([]byte(password), salt, time, memory, threads, uint32(len(expectedHash)))
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if subtle.ConstantTimeCompare(computedHash, expectedHash) != 1 {
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return ErrInvalidCredentials
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}
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return nil
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}
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// MigrateFromPHC converts PHC hash to SCRAM credential
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func MigrateFromPHC(username, password, phcHash string) (*Credential, error) {
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parts := strings.Split(phcHash, "$")
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if len(parts) != 6 || parts[1] != "argon2id" {
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return nil, ErrPHCInvalidFormat
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}
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var memory, time uint32
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var threads uint8
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fmt.Sscanf(parts[3], "m=%d,t=%d,p=%d", &memory, &time, &threads)
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salt, err := base64.RawStdEncoding.DecodeString(parts[4])
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if err != nil {
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return nil, ErrPHCInvalidSalt
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}
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// Use standalone function for verification
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if err := VerifyPassword(password, phcHash); err != nil {
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return nil, err
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}
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return DeriveCredential(username, password, salt, time, memory, threads)
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} |