131 lines
2.8 KiB
Go
131 lines
2.8 KiB
Go
package password
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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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"golang.org/x/crypto/argon2"
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)
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type params struct {
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memory uint32 // en KiB
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iterations uint32
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parallelism uint8
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saltLength uint32
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keyLength uint32
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}
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var defaultParams = ¶ms{
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memory: 64 * 1024, // 64 MB
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iterations: 3,
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parallelism: 2,
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saltLength: 16,
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keyLength: 32,
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}
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// generateSalt crée un salt aléatoire cryptographiquement sûr
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func generateSalt(length uint32) ([]byte, error) {
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salt := make([]byte, length)
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if _, err := rand.Read(salt); err != nil {
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return nil, err
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}
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return salt, nil
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}
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// HashPassword génère un hash Argon2id encodé (salt + hash + paramètres inclus)
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func HashPassword(password string) (string, error) {
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salt, err := generateSalt(defaultParams.saltLength)
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if err != nil {
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return "", err
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}
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hash := argon2.IDKey(
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[]byte(password),
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salt,
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defaultParams.iterations,
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defaultParams.memory,
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defaultParams.parallelism,
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defaultParams.keyLength,
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)
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// Format standard: $argon2id$v=19$m=65536,t=3,p=2$salt$hash
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b64Salt := base64.RawStdEncoding.EncodeToString(salt)
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b64Hash := base64.RawStdEncoding.EncodeToString(hash)
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encoded := fmt.Sprintf(
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"$argon2id$v=%d$m=%d,t=%d,p=%d$%s$%s",
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argon2.Version,
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defaultParams.memory,
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defaultParams.iterations,
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defaultParams.parallelism,
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b64Salt,
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b64Hash,
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)
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return encoded, nil
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}
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// VerifyPassword compare un mot de passe en clair avec un hash stocké
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func VerifyPassword(password, encodedHash string) (bool, error) {
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p, salt, hash, err := decodeHash(encodedHash)
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if err != nil {
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return false, err
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}
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otherHash := argon2.IDKey(
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[]byte(password),
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salt,
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p.iterations,
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p.memory,
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p.parallelism,
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p.keyLength,
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)
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// Comparaison en temps constant pour éviter les timing attacks
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if subtle.ConstantTimeCompare(hash, otherHash) == 1 {
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return true, nil
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}
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return false, nil
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}
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// decodeHash parse la chaîne encodée pour en extraire params, salt et hash
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func decodeHash(encodedHash string) (*params, []byte, []byte, error) {
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parts := strings.Split(encodedHash, "$")
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if len(parts) != 6 {
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return nil, nil, nil, errors.New("format de hash invalide")
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}
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var version int
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_, err := fmt.Sscanf(parts[2], "v=%d", &version)
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if err != nil {
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return nil, nil, nil, err
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}
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if version != argon2.Version {
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return nil, nil, nil, errors.New("version argon2 incompatible")
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}
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p := ¶ms{}
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_, err = fmt.Sscanf(parts[3], "m=%d,t=%d,p=%d", &p.memory, &p.iterations, &p.parallelism)
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if err != nil {
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return nil, nil, nil, 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 nil, nil, nil, err
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}
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p.saltLength = uint32(len(salt))
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hash, err := base64.RawStdEncoding.DecodeString(parts[5])
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if err != nil {
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return nil, nil, nil, err
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}
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p.keyLength = uint32(len(hash))
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return p, salt, hash, nil
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}
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