diff options
Diffstat (limited to 'debian/scripts/passdev.c')
| -rw-r--r-- | debian/scripts/passdev.c | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/debian/scripts/passdev.c b/debian/scripts/passdev.c new file mode 100644 index 0000000..845ccae --- /dev/null +++ b/debian/scripts/passdev.c @@ -0,0 +1,286 @@ +/* + * passdev.c - waits for a given device to appear, mounts it and reads a + * key from it which is piped to stdout. + * + * Copyright (C) 2008 David Härdeman <david@hardeman.nu> + * + * This package 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 2 of the License, or + * (at your option) any later version. + * + * This package 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 package; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + + +#define _DEFAULT_SOURCE +#include <stdio.h> +#include <stdlib.h> +#include <stdarg.h> +#include <stdbool.h> +#include <unistd.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/wait.h> +#include <string.h> +#include <fcntl.h> +#include <sys/mount.h> + +static bool do_debug = false; + +static void +debug(const char *fmt, ...) +{ + va_list ap; + + if (!do_debug) + return; + va_start(ap, fmt); + vfprintf(stderr, fmt, ap); + va_end(ap); +} + +static bool +do_mount(const char *device, const char *dir) +{ + pid_t pid; + int status; + char *fstypes[] = { "ext4", "ext3", "ext2", "vfat", "btrfs", "reiserfs", "xfs", "jfs", "ntfs", "iso9660", "udf" }; + int fsindex; + + if (!device || !dir) + return false; + + for (fsindex = 0; + fsindex < (sizeof(fstypes) / sizeof(fstypes[0])); + fsindex++) + { + pid = fork(); + if (pid < 0) { + /* Error */ + return false; + } else if (pid > 0) { + /* We're in the parent process */ + do { + waitpid(pid, &status, 0); + } while (!WIFEXITED(status) && !WIFSIGNALED(status)); + if (WIFEXITED(status) && WEXITSTATUS(status) == EXIT_SUCCESS) + return true; + + /* Let's try another fstype */ + continue; + } else { + /* We're in the child process */ + debug("Mounting %s at %s\n", device, dir); + close(STDIN_FILENO); + close(STDOUT_FILENO); + close(STDERR_FILENO); + open("/dev/null", O_RDONLY, 0); + open("/dev/null", O_WRONLY, 0); + open("/dev/null", O_WRONLY, 0); + execl("/bin/mount", "/bin/mount", "-n", "-t", + fstypes[fsindex], + /*"ext4,ext3,ext2,vfat,btrfs,reiserfs,xfs,jfs,ntfs,iso9660,udf",*/ + "-o", "noatime,nodiratime,nodev,noexec,nosuid,ro", + device, dir, (char *)NULL); + + /* If execl works, we won't end up here */ + exit(EXIT_FAILURE); + } + } + + /* We've tried all fstypes with no luck */ + return false; +} + +int +main(int argc, char **argv, char **envp) +{ + char *debugval; + char *devpath; + char *filepath; + struct stat st; + char *tmppath; + char tpath[] = "/tmp/passdev.XXXXXX"; + char *keypath; + int fd; + size_t toread; + size_t bytesread; + char *keybuffer; + size_t towrite; + size_t byteswritten; + ssize_t bytes; + char *to; + int timeout = 0; + bool do_timeout = false; + + /* We only take one argument */ + if (argc != 2) { + fprintf(stderr, "Incorrect number of arguments\n"); + goto error; + } + + /* If DEBUG=1 is in the environment, enable debug messages */ + debugval = getenv("DEBUG"); + if (debugval && atoi(debugval) > 0) + do_debug = true; + + /* Split string into device and path (and timeout) */ + devpath = argv[1]; + filepath = strchr(devpath, ':'); + if (!filepath || !(*filepath) || !(*(filepath + 1))) { + fprintf(stderr, "Invalid key path\n"); + goto error; + } + *filepath = '\0'; + filepath++; + to = strchr(filepath, ':'); + if (to && (*to) && (*(to + 1))) { + *to = '\0'; + to++; + timeout = atoi(to); + if (timeout > 0) + do_timeout = true; + } + debug("Path is %p and filepath is %p\n", devpath, filepath); + if (do_timeout) + debug("Timeout is %i\n",timeout); + + /* Wait until device is available */ + if (access(devpath, F_OK)) { + debug("Waiting for %s\n", devpath); + while(access(devpath, F_OK)) { + sleep(1); + if (do_timeout) { + if (timeout <= 0) + break; + timeout--; + } + } + } + + /* Make sure device is a blockdev */ + if (stat(devpath, &st)) { + fprintf(stderr, "Unable to stat %s\n", devpath); + goto error; + } else if (!S_ISBLK(st.st_mode)) { + fprintf(stderr, "%s is no block device\n", devpath); + goto error; + } + + /* Create a tmp dir where we mount the device */ + tmppath = mkdtemp(tpath); + if (!tmppath) { + fprintf(stderr, "Failed to create temporary directory\n"); + goto error; + } + + /* Ok, mount it */ + if (!do_mount(devpath, tmppath)) { + fprintf(stderr, "Failed to mount %s\n", devpath); + goto error_rmdir; + } + + /* Generate the full path to the keyfile */ + keypath = malloc(strlen(tmppath) + 1 + strlen(filepath) + 1); + if (!keypath) { + fprintf(stderr, "Failed to allocate memory\n"); + goto error_umount; + } + sprintf(keypath, "%s/%s", tmppath, filepath); + + /* Check that the keyfile exists */ + if (access(keypath, F_OK)) { + fprintf(stderr, "Keyfile doesn't exist\n"); + goto error_free; + } + + /* Get the size of the keyfile */ + if (stat(keypath, &st)) { + fprintf(stderr, "Unable to stat keyfile\n"); + goto error_free; + } + + /* Check the size of the keyfile */ + if (st.st_size < 0) { + fprintf(stderr, "Invalid keyfile size\n"); + goto error_free; + } + toread = (size_t)st.st_size; + + /* Open the keyfile */ + if ((fd = open(keypath, O_RDONLY)) < 0) { + fprintf(stderr, "Failed to open keyfile\n"); + goto error_free; + } + + /* Allocate a buffer for the keyfile contents */ + keybuffer = malloc(toread); + if (!keybuffer) { + fprintf(stderr, "Failed to allocate memory\n"); + goto error_close; + exit(EXIT_FAILURE); + } + + /* Read the keyfile */ + bytesread = 0; + while (bytesread < toread) { + bytes = read(fd, keybuffer + bytesread, toread - bytesread); + if (bytes <= 0) { + fprintf(stderr, "Failed to read entire key\n"); + goto error_keybuffer; + } + bytesread += bytes; + } + + /* Clean up */ + close(fd); + free(keypath); + umount(tmppath); + rmdir(tmppath); + + /* Write result */ + byteswritten = 0; + towrite = toread; + while (byteswritten < towrite) { + bytes = write(STDOUT_FILENO, keybuffer + byteswritten, + towrite - byteswritten); + if (bytes <= 0) { + fprintf(stderr, "Failed to write entire key\n"); + memset(keybuffer, 0, toread); + free(keybuffer); + goto error; + } + byteswritten += bytes; + } + + /* Clean up */ + memset(keybuffer, 0, toread); + free(keybuffer); + + /* Done */ + exit(EXIT_SUCCESS); + + /* Error handling */ +error_keybuffer: + memset(keybuffer, 0, toread); + free(keybuffer); +error_close: + close(fd); +error_free: + free(keypath); +error_umount: + umount(tmppath); +error_rmdir: + rmdir(tmppath); +error: + exit(EXIT_FAILURE); +} + |