diff options
Diffstat (limited to 'utility/mount-helpers.c')
| -rw-r--r-- | utility/mount-helpers.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/utility/mount-helpers.c b/utility/mount-helpers.c index 927adb11..893d43e0 100644 --- a/utility/mount-helpers.c +++ b/utility/mount-helpers.c @@ -147,6 +147,48 @@ uint8_t *hexify_string(char *string, uint8_t *binary, size_t length) return binary; } +/* Overwrite file contents. Useless on SSD. :( */ +void shred(const char *pathname) +{ + uint8_t patterns[] = { 0xA5, 0x5A, 0xFF, 0x00 }; + FILE *target; + struct stat info; + uint8_t *pattern; + int fd, i; + + /* Give up if we can't safely open or stat the target. */ + if ((fd = open(pathname, O_WRONLY | O_NOFOLLOW)) < 0) { + PERROR(pathname); + return; + } + if (fstat(fd, &info)) { + close(fd); + PERROR(pathname); + return; + } + if (!(target = fdopen(fd, "w"))) { + close(fd); + PERROR(pathname); + return; + } + /* Ignore errors here, since there's nothing we can really do. */ + pattern = malloc(info.st_size); + for (i = 0; i < sizeof(patterns); ++i) { + memset(pattern, patterns[i], info.st_size); + if (fseek(target, 0, SEEK_SET)) + PERROR(pathname); + if (fwrite(pattern, info.st_size, 1, target) != 1) + PERROR(pathname); + if (fflush(target)) + PERROR(pathname); + if (fdatasync(fd)) + PERROR(pathname); + } + free(pattern); + /* fclose() closes the fd too. */ + fclose(target); +} + static int is_loop_device(int fd) { struct stat info; @@ -662,6 +704,13 @@ int keyfile_write(const char *keyfile, uint8_t *system_key, char *string) length = cipher_length + final_len; DEBUG("Writing %zu bytes to %s", length, keyfile); + /* TODO(keescook): use fd here, and set secure delete. Unsupported + * by ext4 currently. :( + * int f; + * ioctl(fd, EXT2_IOC_GETFLAGS, &f); + * f |= EXT2_SECRM_FL; + * ioctl(fd, EXT2_IOC_SETFLAGS, &f); + */ if (!g_file_set_contents(keyfile, (gchar *)cipher, length, &error)) { ERROR("Unable to write %s: %s", keyfile, error->message); g_error_free(error); |