nuts-foundation/nuts-node

/*
 * Copyright (C) 2022 Nuts community
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */

package spi

import (
    "context"
    "crypto"
    "fmt"
    "github.com/nuts-foundation/nuts-node/core"
    "regexp"
)

// wrapper wraps a Storage backend and checks the validity of the kid on each of the relevant functions before
// forwarding the call to the wrapped backend.
type wrapper struct {
    kidPattern     *regexp.Regexp
    wrappedBackend Storage
}

func (w wrapper) Name() string {
    return w.wrappedBackend.Name()
}

func (w wrapper) CheckHealth() map[string]core.Health {
    return w.wrappedBackend.CheckHealth()
}

// NewValidatedKIDBackendWrapper creates a new wrapper for storage backends.
// Every call to the backend which takes a kid as param, gets the kid validated against the provided kidPattern.
func NewValidatedKIDBackendWrapper(backend Storage, kidPattern *regexp.Regexp) Storage {
    return wrapper{
        kidPattern:     kidPattern,
        wrappedBackend: backend,
    }
}

func (w wrapper) validateKID(kid string) error {
    if !w.kidPattern.MatchString(kid) {
        return fmt.Errorf("invalid key ID: %s", kid)
    }
    return nil
}

func (w wrapper) GetPrivateKey(ctx context.Context, kid string) (crypto.Signer, error) {
    if err := w.validateKID(kid); err != nil {
        return nil, err
    }
    return w.wrappedBackend.GetPrivateKey(ctx, kid)
}

func (w wrapper) PrivateKeyExists(ctx context.Context, kid string) (bool, error) {
    if err := w.validateKID(kid); err != nil {
        return false, err
    }
    return w.wrappedBackend.PrivateKeyExists(ctx, kid)
}

func (w wrapper) SavePrivateKey(ctx context.Context, kid string, key crypto.PrivateKey) error {
    if err := w.validateKID(kid); err != nil {
        return err
    }
    return w.wrappedBackend.SavePrivateKey(ctx, kid, key)
}

func (w wrapper) DeletePrivateKey(ctx context.Context, kid string) error {
    if err := w.validateKID(kid); err != nil {
        return err
    }
    return w.wrappedBackend.DeletePrivateKey(ctx, kid)
}

func (w wrapper) ListPrivateKeys(ctx context.Context) []string {
    return w.wrappedBackend.ListPrivateKeys(ctx)
}

func (w wrapper) NewPrivateKey(ctx context.Context, namingFunc func(crypto.PublicKey) (string, error)) (crypto.PublicKey, string, error) {
    publicKey, kid, err := w.wrappedBackend.NewPrivateKey(ctx, namingFunc)
    if err != nil {
        return nil, "", err
    }
    if err := w.validateKID(kid); err != nil {
        return nil, "", err
    }
    return publicKey, kid, err
}