feat: bcrypt cost provisioning

modules/caddyhttp/caddyauth/command.go

@@ -116,7 +116,7 @@ func cmdHashPassword(fs caddycmd.Flags) (int, error) {
 	var hashString string
 	switch algorithm {
 	case "bcrypt":
-		hash, err = BcryptHash{cost: bcryptCost}.Hash(plaintext)
+		hash, err = BcryptHash{Cost: bcryptCost}.Hash(plaintext)
 		hashString = string(hash)
 	default:
 		return caddy.ExitCodeFailedStartup, fmt.Errorf("unrecognized hash algorithm: %s", algorithm)

modules/caddyhttp/caddyauth/hashes.go

@@ -30,9 +30,9 @@ const defaultBcryptCost = 14
 
 // BcryptHash implements the bcrypt hash.
 type BcryptHash struct {
-	// cost is the bcrypt hashing difficulty factor (work factor).
+	// Cost is the bcrypt hashing difficulty factor (work factor).
 	// Higher values increase computation time and security.
-	cost int
+	Cost int
 }
 
 // CaddyModule returns the Caddy module information.
@@ -43,6 +43,15 @@ func (BcryptHash) CaddyModule() caddy.ModuleInfo {
 	}
 }
 
+// Provision sets up default values.
+func (b *BcryptHash) Provision(ctx caddy.Context) error {
+	if b.Cost < bcrypt.MinCost || b.Cost > bcrypt.MaxCost {
+		b.Cost = defaultBcryptCost
+	}
+
+	return nil
+}
+
 // Compare compares passwords.
 func (BcryptHash) Compare(hashed, plaintext []byte) (bool, error) {
 	err := bcrypt.CompareHashAndPassword(hashed, plaintext)
@@ -57,12 +66,7 @@ func (BcryptHash) Compare(hashed, plaintext []byte) (bool, error) {
 
 // Hash hashes plaintext using a random salt.
 func (b BcryptHash) Hash(plaintext []byte) ([]byte, error) {
-	cost := b.cost
-	if cost < bcrypt.MinCost || cost > bcrypt.MaxCost {
-		cost = defaultBcryptCost
-	}
-
-	return bcrypt.GenerateFromPassword(plaintext, cost)
+	return bcrypt.GenerateFromPassword(plaintext, b.Cost)
 }
 
 // FakeHash returns a fake hash.
@@ -74,6 +78,7 @@ func (BcryptHash) FakeHash() []byte {
 
 // Interface guards
 var (
-	_ Comparer = (*BcryptHash)(nil)
-	_ Hasher   = (*BcryptHash)(nil)
+	_ Comparer          = (*BcryptHash)(nil)
+	_ Hasher            = (*BcryptHash)(nil)
+	_ caddy.Provisioner = (*BcryptHash)(nil)
 )