include/cryptsetupInterface.hpp

#pragma once

#include <libcryptsetup.h>

#include <stdplus/handle/managed.hpp>

namespace estoraged
{

/** @class CryptsetupInterface
 *  @brief Interface to the cryptsetup functions used to manage a LUKS device.
 *  @details This class is used to mock out the cryptsetup functions.
 */
class CryptsetupInterface
{
  public:
    virtual ~CryptsetupInterface() = default;

    /** @brief Wrapper around crypt_format.
     *  @details Used for mocking purposes.
     *
     *  @param[in] cd - crypt device handle.
     *  @param[in] type - type of device (optional params struct must be of
     *    this type).
     *  @param[in] cipher - (e.g. "aes").
     *  @params[in cipher_mode - including IV specification (e.g. "xts-plain").
     *  @params[in] uuid - requested UUID or NULL if it should be generated.
     *  @params[in] volume_key - pre-generated volume key or NULL if it should
     *    be generated (only for LUKS).
     *  @params[in] volume_key_size - size of volume key in bytes.
     *  @params[in] params - crypt type specific parameters.
     *
     *  @returns 0 on success or negative errno value otherwise.
     */
    virtual int cryptFormat(struct crypt_device* cd, const char* type,
                            const char* cipher, const char* cipherMode,
                            const char* uuid, const char* volumeKey,
                            size_t volumeKeySize, void* params) = 0;

    /** @brief Wrapper around crypt_keyslot_add_by_volume_key.
     *  @details Used for mocking purposes.
     *
     *  @param[in] cd - crypt device handle.
     *  @param[in] keyslot - requested keyslot or CRYPT_ANY_SLOT.
     *  @param[in] volume_key - provided volume key or NULL if used after
     *    crypt_format.
     *  @param[in] volume_key_size - size of volume_key.
     *  @param[in] passphrase - passphrase for new keyslot.
     *  @param[in] passphrase_size - size of passphrase.
     *
     *  @returns allocated key slot number or negative errno otherwise.
     */
    virtual int cryptKeyslotAddByVolumeKey(struct crypt_device* cd, int keyslot,
                                           const char* volumeKey,
                                           size_t volumeKeySize,
                                           const char* passphrase,
                                           size_t passphraseSize) = 0;

    /** @brief Wrapper around crypt_load.
     *  @details Used for mocking purposes.
     *
     *  @param[in] cd - crypt device handle.
     *  @param[in] requested_type - crypt-type or NULL for all known.
     *  @param[in] params - crypt type specific parameters (see crypt-type).
     *
     *  @returns 0 on success or negative errno value otherwise.
     */
    virtual int cryptLoad(struct crypt_device* cd, const char* requestedType,
                          void* params) = 0;

    /** @brief Wrapper around crypt_activate_by_passphrase.
     *  @details Used for mocking purposes.
     *
     *  @param[in] cd - crypt device handle.
     *  @param[in] name - name of device to create, if NULL only check
     *    passphrase.
     *  @param[in] keyslot - requested keyslot to check or CRYPT_ANY_SLOT.
     *  @param[in] passphrase - passphrase used to unlock volume key.
     *  @param[in] passphrase_size - size of passphrase.
     *  @param[in] flags - activation flags.
     *
     *  @returns unlocked key slot number or negative errno otherwise.
     */
    virtual int cryptActivateByPassphrase(struct crypt_device* cd,
                                          const char* name, int keyslot,
                                          const char* passphrase,
                                          size_t passphraseSize,
                                          uint32_t flags) = 0;

    /** @brief Wrapper around crypt_deactivate.
     *  @details Used for mocking purposes.
     *
     *  @param[in] cd - crypt device handle, can be NULL.
     *  @param[in] name - name of device to deactivate.
     *
     *  @returns 0 on success or negative errno value otherwise.
     */
    virtual int cryptDeactivate(struct crypt_device* cd, const char* name) = 0;
};

/** @class Cryptsetup
 *  @brief Implements CryptsetupInterface.
 */
class Cryptsetup : public CryptsetupInterface
{
  public:
    ~Cryptsetup() = default;

    int cryptFormat(struct crypt_device* cd, const char* type,
                    const char* cipher, const char* cipherMode,
                    const char* uuid, const char* volumeKey,
                    size_t volumeKeySize, void* params) override
    {
        return crypt_format(cd, type, cipher, cipherMode, uuid, volumeKey,
                            volumeKeySize, params);
    }

    int cryptKeyslotAddByVolumeKey(struct crypt_device* cd, int keyslot,
                                   const char* volumeKey, size_t volumeKeySize,
                                   const char* passphrase,
                                   size_t passphraseSize) override
    {
        return crypt_keyslot_add_by_volume_key(
            cd, keyslot, volumeKey, volumeKeySize, passphrase, passphraseSize);
    }

    int cryptLoad(struct crypt_device* cd, const char* requestedType,
                  void* params) override
    {
        return crypt_load(cd, requestedType, params);
    }

    int cryptActivateByPassphrase(struct crypt_device* cd, const char* name,
                                  int keyslot, const char* passphrase,
                                  size_t passphraseSize,
                                  uint32_t flags) override
    {
        return crypt_activate_by_passphrase(cd, name, keyslot, passphrase,
                                            passphraseSize, flags);
    }

    int cryptDeactivate(struct crypt_device* cd, const char* name) override
    {
        return crypt_deactivate(cd, name);
    }
};

/** @class CryptHandle
 *  @brief This manages a crypt_device struct and automatically frees it when
 *  this handle exits the current scope.
 */
class CryptHandle
{
  public:
    /** @brief Constructor for CryptHandle
     *
     *  @param[in] device - path to device file
     */
    explicit CryptHandle(const char* device) : handle(init(device))
    {}

    /** @brief Get a pointer to the crypt_device struct. */
    struct crypt_device* get()
    {
        return *handle;
    }

  private:
    /** @brief Allocate and initialize the crypt_device struct
     *
     *  @param[in] device - path to device file
     */
    struct crypt_device* init(const char* device)
    {
        struct crypt_device* cryptDev;
        int retval = crypt_init(&cryptDev, device);
        if (retval < 0)
        {
            return nullptr;
        }

        return cryptDev;
    }

    /** @brief Free the crypt_device struct
     *
     *  @param[in] cd - pointer to crypt_device*, to be freed
     */
    static void cryptFree(struct crypt_device*&& cd)
    {
        crypt_free(cd);
    }

    /** @brief Managed handle to crypt_device struct */
    stdplus::Managed<struct crypt_device*>::Handle<cryptFree> handle;
};

} // namespace estoraged