Function encrypt_hsm

tools/lightning-hsmtool.c:169–249

Legacy function - only works with binary plain format */

/* Legacy function - only works with binary plain format */
static void encrypt_hsm(const char *hsm_secret_path)
{
	int fd;
	struct hsm_secret *hsms;
	u8 encrypted_hsm_secret[ENCRYPTED_HSM_SECRET_LEN];
	const char *passwd, *passwd_confirmation;
	const char *dir, *backup;
	enum hsm_secret_error pass_err;

	/* Check if it's a format we can encrypt */
	u8 *contents = grab_file_raw(tmpctx, hsm_secret_path);
	if (!contents)
		err(EXITCODE_ERROR_HSM_FILE, "Reading hsm_secret");

	enum hsm_secret_type type = detect_hsm_secret_type(contents, tal_bytelen(contents));

	if (type != HSM_SECRET_PLAIN) {
		errx(ERROR_USAGE, "encrypt command only works on legacy plain binary format (32 bytes).\n"
		                  "Current file is: %s\n"
		                  "For mnemonic formats, the passphrase is already integrated into the format.",
		                  format_type_name(type));
	}

	/* Load the hsm_secret */
	hsms = load_hsm_secret(tmpctx, hsm_secret_path);

	printf("Enter hsm_secret password:\n");
	fflush(stdout);
	passwd = read_stdin_pass(tmpctx, &pass_err);
	if (!passwd)
		errx(EXITCODE_ERROR_HSM_FILE, "Could not read password: %s", hsm_secret_error_str(pass_err));

	printf("Confirm hsm_secret password:\n");
	fflush(stdout);
	passwd_confirmation = read_stdin_pass(tmpctx, &pass_err);
	if (!passwd_confirmation)
		errx(EXITCODE_ERROR_HSM_FILE, "Could not read password: %s", hsm_secret_error_str(pass_err));

	if (!streq(passwd, passwd_confirmation))
		errx(ERROR_USAGE, "Passwords confirmation mismatch.");

	dir = path_dirname(NULL, hsm_secret_path);
	backup = path_join(dir, dir, "hsm_secret.backup");

	/* Create encryption key and encrypt */
	struct secret *encryption_key = get_encryption_key(tmpctx, passwd);
	if (!encryption_key)
		errx(ERROR_LIBSODIUM, "Could not derive encryption key");

	struct secret legacy_secret;
	memcpy(legacy_secret.data, hsms->secret_data, 32);
	if (!encrypt_legacy_hsm_secret(encryption_key, &legacy_secret, encrypted_hsm_secret))
		errx(ERROR_LIBSODIUM, "Could not encrypt the hsm_secret seed.");

	/* Create a backup file, "just in case". */
	rename(hsm_secret_path, backup);
	fd = open(hsm_secret_path, O_CREAT|O_EXCL|O_WRONLY, 0400);
	if (fd < 0)