121 lines
3.6 KiB
C
121 lines
3.6 KiB
C
/*
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luksrku - Tool to remotely unlock LUKS disks using TLS.
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Copyright (C) 2016-2016 Johannes Bauer
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This file is part of luksrku.
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luksrku is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; this program is ONLY licensed under
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version 3 of the License, later versions are explicitly excluded.
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luksrku is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with luksrku; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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Johannes Bauer <JohannesBauer@gmx.de>
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*/
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#include <stdio.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include "luks.h"
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#include "log.h"
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#include "exec.h"
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#include "util.h"
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bool is_luks_device_opened(const char *mapping_name) {
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const char *command[] = {
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"dmsetup",
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"status",
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mapping_name,
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NULL,
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};
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struct runresult_t runresult = exec_command(command);
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return runresult.success && (runresult.returncode == 0);
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}
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bool open_luks_device(const uint8_t *encrypted_device_uuid, const char *mapping_name, const char *passphrase_file) {
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char encrypted_device[64];
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strcpy(encrypted_device, "UUID=");
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sprintf_uuid(encrypted_device + 5, encrypted_device_uuid);
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log_msg(LLVL_INFO, "Trying to unlock LUKS mapping %s based on %s", mapping_name, encrypted_device);
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const char *command[] = {
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"cryptsetup",
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"luksOpen",
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"-T", "1",
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"-d", passphrase_file,
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encrypted_device,
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mapping_name,
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NULL,
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};
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struct runresult_t runresult = exec_command(command);
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return runresult.success && (runresult.returncode == 0);
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}
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static bool wipe_passphrase_file(const char *filename, int length) {
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uint8_t wipe_buf[length];
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memset(wipe_buf, 0, length);
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int fd = open(filename, O_WRONLY);
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if (fd == -1) {
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log_libc(LLVL_ERROR, "Wiping of passphrase file %s failed in open(2)", filename);
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return false;
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}
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if (write(fd, wipe_buf, length) != length) {
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log_libc(LLVL_ERROR, "Wiping of passphrase file %s failed in write(2)", filename);
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close(fd);
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return false;
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}
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close(fd);
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unlink(filename);
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return true;
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}
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static const char *write_passphrase_file(const uint8_t *passphrase, int passphrase_length) {
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//const char *filename = "/dev/shm/luksrku_passphrase.bin"; /* TODO make this variable */
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const char *filename = "/tmp/luksrku_passphrase.bin";
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int fd = open(filename, O_CREAT | O_WRONLY | O_TRUNC, 0600);
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if (fd == -1) {
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log_libc(LLVL_ERROR, "Creation of passphrase file %s failed", filename);
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return NULL;
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}
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if (write(fd, passphrase, passphrase_length) != passphrase_length) {
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log_libc(LLVL_ERROR, "Writing to passphrase file %s failed", filename);
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wipe_passphrase_file(filename, passphrase_length);
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close(fd);
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return NULL;
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}
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close(fd);
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return filename;
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}
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bool open_luks_device_pw(const uint8_t *encrypted_device_uuid, const char *mapping_name, const uint8_t *passphrase, int passphrase_length) {
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const char *pw_filename = write_passphrase_file(passphrase, passphrase_length);
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if (!pw_filename) {
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return false;
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}
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bool success = open_luks_device(encrypted_device_uuid, mapping_name, pw_filename);
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if (!wipe_passphrase_file(pw_filename, passphrase_length)) {
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log_libc(LLVL_ERROR, "Wiping of passphrase file failed -- treating this unlock as failed (luksOpen %s)", success ? "succeeded" : "also failed");
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success = false;
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}
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return success;
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}
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