diff options
Diffstat (limited to 'src/cryptsetup/cryptsetup-generator.c')
| -rw-r--r-- | src/cryptsetup/cryptsetup-generator.c | 609 |
1 files changed, 609 insertions, 0 deletions
diff --git a/src/cryptsetup/cryptsetup-generator.c b/src/cryptsetup/cryptsetup-generator.c new file mode 100644 index 0000000..8759a26 --- /dev/null +++ b/src/cryptsetup/cryptsetup-generator.c @@ -0,0 +1,609 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include <errno.h> +#include <stdio_ext.h> + +#include "alloc-util.h" +#include "dropin.h" +#include "escape.h" +#include "fd-util.h" +#include "fileio.h" +#include "fstab-util.h" +#include "generator.h" +#include "hashmap.h" +#include "id128-util.h" +#include "log.h" +#include "mkdir.h" +#include "parse-util.h" +#include "path-util.h" +#include "proc-cmdline.h" +#include "specifier.h" +#include "string-util.h" +#include "strv.h" +#include "unit-name.h" +#include "util.h" + +typedef struct crypto_device { + char *uuid; + char *keyfile; + char *keydev; + char *name; + char *options; + bool create; +} crypto_device; + +static const char *arg_dest = NULL; +static bool arg_enabled = true; +static bool arg_read_crypttab = true; +static bool arg_whitelist = false; +static Hashmap *arg_disks = NULL; +static char *arg_default_options = NULL; +static char *arg_default_keyfile = NULL; + +STATIC_DESTRUCTOR_REGISTER(arg_disks, hashmap_freep); +STATIC_DESTRUCTOR_REGISTER(arg_default_options, freep); +STATIC_DESTRUCTOR_REGISTER(arg_default_keyfile, freep); + +static int generate_keydev_mount(const char *name, const char *keydev, char **unit, char **mount) { + _cleanup_free_ char *u = NULL, *what = NULL, *where = NULL, *name_escaped = NULL; + _cleanup_fclose_ FILE *f = NULL; + int r; + + assert(name); + assert(keydev); + assert(unit); + assert(mount); + + r = mkdir_parents("/run/systemd/cryptsetup", 0755); + if (r < 0) + return r; + + r = mkdir("/run/systemd/cryptsetup", 0700); + if (r < 0 && errno != EEXIST) + return -errno; + + name_escaped = cescape(name); + if (!name_escaped) + return -ENOMEM; + + where = strjoin("/run/systemd/cryptsetup/keydev-", name_escaped); + if (!where) + return -ENOMEM; + + r = mkdir(where, 0700); + if (r < 0 && errno != EEXIST) + return -errno; + + r = unit_name_from_path(where, ".mount", &u); + if (r < 0) + return r; + + r = generator_open_unit_file(arg_dest, NULL, u, &f); + if (r < 0) + return r; + + what = fstab_node_to_udev_node(keydev); + if (!what) + return -ENOMEM; + + fprintf(f, + "[Unit]\n" + "DefaultDependencies=no\n\n" + "[Mount]\n" + "What=%s\n" + "Where=%s\n" + "Options=ro\n", what, where); + + r = fflush_and_check(f); + if (r < 0) + return r; + + *unit = TAKE_PTR(u); + *mount = TAKE_PTR(where); + + return 0; +} + +static int create_disk( + const char *name, + const char *device, + const char *keydev, + const char *password, + const char *options) { + + _cleanup_free_ char *n = NULL, *d = NULL, *u = NULL, *e = NULL, + *filtered = NULL, *u_escaped = NULL, *password_escaped = NULL, *filtered_escaped = NULL, *name_escaped = NULL, *keydev_mount = NULL; + _cleanup_fclose_ FILE *f = NULL; + const char *dmname; + bool noauto, nofail, tmp, swap, netdev; + int r; + + assert(name); + assert(device); + + noauto = fstab_test_yes_no_option(options, "noauto\0" "auto\0"); + nofail = fstab_test_yes_no_option(options, "nofail\0" "fail\0"); + tmp = fstab_test_option(options, "tmp\0"); + swap = fstab_test_option(options, "swap\0"); + netdev = fstab_test_option(options, "_netdev\0"); + + if (tmp && swap) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Device '%s' cannot be both 'tmp' and 'swap'. Ignoring.", + name); + + name_escaped = specifier_escape(name); + if (!name_escaped) + return log_oom(); + + e = unit_name_escape(name); + if (!e) + return log_oom(); + + u = fstab_node_to_udev_node(device); + if (!u) + return log_oom(); + + r = unit_name_build("systemd-cryptsetup", e, ".service", &n); + if (r < 0) + return log_error_errno(r, "Failed to generate unit name: %m"); + + u_escaped = specifier_escape(u); + if (!u_escaped) + return log_oom(); + + r = unit_name_from_path(u, ".device", &d); + if (r < 0) + return log_error_errno(r, "Failed to generate unit name: %m"); + + if (password) { + password_escaped = specifier_escape(password); + if (!password_escaped) + return log_oom(); + } + + if (keydev && !password) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Key device is specified, but path to the password file is missing."); + + r = generator_open_unit_file(arg_dest, NULL, n, &f); + if (r < 0) + return r; + + fprintf(f, + "[Unit]\n" + "Description=Cryptography Setup for %%I\n" + "Documentation=man:crypttab(5) man:systemd-cryptsetup-generator(8) man:systemd-cryptsetup@.service(8)\n" + "SourcePath=/etc/crypttab\n" + "DefaultDependencies=no\n" + "Conflicts=umount.target\n" + "IgnoreOnIsolate=true\n" + "After=%s\n", + netdev ? "remote-fs-pre.target" : "cryptsetup-pre.target"); + + if (keydev) { + _cleanup_free_ char *unit = NULL, *p = NULL; + + r = generate_keydev_mount(name, keydev, &unit, &keydev_mount); + if (r < 0) + return log_error_errno(r, "Failed to generate keydev mount unit: %m"); + + p = prefix_root(keydev_mount, password_escaped); + if (!p) + return log_oom(); + + free_and_replace(password_escaped, p); + } + + if (!nofail) + fprintf(f, + "Before=%s\n", + netdev ? "remote-cryptsetup.target" : "cryptsetup.target"); + + if (password) { + if (PATH_IN_SET(password, "/dev/urandom", "/dev/random", "/dev/hw_random")) + fputs("After=systemd-random-seed.service\n", f); + else if (!STR_IN_SET(password, "-", "none")) { + _cleanup_free_ char *uu; + + uu = fstab_node_to_udev_node(password); + if (!uu) + return log_oom(); + + if (!path_equal(uu, "/dev/null")) { + + if (path_startswith(uu, "/dev/")) { + _cleanup_free_ char *dd = NULL; + + r = unit_name_from_path(uu, ".device", &dd); + if (r < 0) + return log_error_errno(r, "Failed to generate unit name: %m"); + + fprintf(f, "After=%1$s\nRequires=%1$s\n", dd); + } else + fprintf(f, "RequiresMountsFor=%s\n", password_escaped); + } + } + } + + if (path_startswith(u, "/dev/")) { + fprintf(f, + "BindsTo=%s\n" + "After=%s\n" + "Before=umount.target\n", + d, d); + + if (swap) + fputs("Before=dev-mapper-%i.swap\n", + f); + } else + /* For loopback devices, add systemd-tmpfiles-setup-dev.service + dependency to ensure that loopback support is available in + the kernel (/dev/loop-control needs to exist) */ + fprintf(f, + "RequiresMountsFor=%s\n" + "Requires=systemd-tmpfiles-setup-dev.service\n" + "After=systemd-tmpfiles-setup-dev.service\n", + u_escaped); + + r = generator_write_timeouts(arg_dest, device, name, options, &filtered); + if (r < 0) + return r; + + if (filtered) { + filtered_escaped = specifier_escape(filtered); + if (!filtered_escaped) + return log_oom(); + } + + fprintf(f, + "\n[Service]\n" + "Type=oneshot\n" + "RemainAfterExit=yes\n" + "TimeoutSec=0\n" /* the binary handles timeouts anyway */ + "KeyringMode=shared\n" /* make sure we can share cached keys among instances */ + "ExecStart=" SYSTEMD_CRYPTSETUP_PATH " attach '%s' '%s' '%s' '%s'\n" + "ExecStop=" SYSTEMD_CRYPTSETUP_PATH " detach '%s'\n", + name_escaped, u_escaped, strempty(password_escaped), strempty(filtered_escaped), + name_escaped); + + if (tmp) + fprintf(f, + "ExecStartPost=/sbin/mke2fs '/dev/mapper/%s'\n", + name_escaped); + + if (swap) + fprintf(f, + "ExecStartPost=/sbin/mkswap '/dev/mapper/%s'\n", + name_escaped); + + if (keydev) + fprintf(f, + "ExecStartPost=" UMOUNT_PATH " %s\n\n", + keydev_mount); + + r = fflush_and_check(f); + if (r < 0) + return log_error_errno(r, "Failed to write unit file %s: %m", n); + + if (!noauto) { + r = generator_add_symlink(arg_dest, d, "wants", n); + if (r < 0) + return r; + + r = generator_add_symlink(arg_dest, + netdev ? "remote-cryptsetup.target" : "cryptsetup.target", + nofail ? "wants" : "requires", n); + if (r < 0) + return r; + } + + dmname = strjoina("dev-mapper-", e, ".device"); + r = generator_add_symlink(arg_dest, dmname, "requires", n); + if (r < 0) + return r; + + if (!noauto && !nofail) { + r = write_drop_in(arg_dest, dmname, 90, "device-timeout", + "# Automatically generated by systemd-cryptsetup-generator \n\n" + "[Unit]\nJobTimeoutSec=0"); + if (r < 0) + return log_error_errno(r, "Failed to write device drop-in: %m"); + } + + return 0; +} + +static crypto_device* crypt_device_free(crypto_device *d) { + if (!d) + return NULL; + + free(d->uuid); + free(d->keyfile); + free(d->keydev); + free(d->name); + free(d->options); + return mfree(d); +} + +static crypto_device *get_crypto_device(const char *uuid) { + int r; + crypto_device *d; + + assert(uuid); + + d = hashmap_get(arg_disks, uuid); + if (!d) { + d = new0(struct crypto_device, 1); + if (!d) + return NULL; + + d->create = false; + d->keyfile = d->options = d->name = NULL; + + d->uuid = strdup(uuid); + if (!d->uuid) + return mfree(d); + + r = hashmap_put(arg_disks, d->uuid, d); + if (r < 0) { + free(d->uuid); + return mfree(d); + } + } + + return d; +} + +static int parse_proc_cmdline_item(const char *key, const char *value, void *data) { + _cleanup_free_ char *uuid = NULL, *uuid_value = NULL; + crypto_device *d; + int r; + + if (streq(key, "luks")) { + + r = value ? parse_boolean(value) : 1; + if (r < 0) + log_warning("Failed to parse luks= kernel command line switch %s. Ignoring.", value); + else + arg_enabled = r; + + } else if (streq(key, "luks.crypttab")) { + + r = value ? parse_boolean(value) : 1; + if (r < 0) + log_warning("Failed to parse luks.crypttab= kernel command line switch %s. Ignoring.", value); + else + arg_read_crypttab = r; + + } else if (streq(key, "luks.uuid")) { + + if (proc_cmdline_value_missing(key, value)) + return 0; + + d = get_crypto_device(startswith(value, "luks-") ? value+5 : value); + if (!d) + return log_oom(); + + d->create = arg_whitelist = true; + + } else if (streq(key, "luks.options")) { + + if (proc_cmdline_value_missing(key, value)) + return 0; + + r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value); + if (r == 2) { + d = get_crypto_device(uuid); + if (!d) + return log_oom(); + + free_and_replace(d->options, uuid_value); + } else if (free_and_strdup(&arg_default_options, value) < 0) + return log_oom(); + + } else if (streq(key, "luks.key")) { + size_t n; + _cleanup_free_ char *keyfile = NULL, *keydev = NULL; + char *c; + const char *keyspec; + + if (proc_cmdline_value_missing(key, value)) + return 0; + + n = strspn(value, LETTERS DIGITS "-"); + if (value[n] != '=') { + if (free_and_strdup(&arg_default_keyfile, value) < 0) + return log_oom(); + return 0; + } + + uuid = strndup(value, n); + if (!uuid) + return log_oom(); + + if (!id128_is_valid(uuid)) { + log_warning("Failed to parse luks.key= kernel command line switch. UUID is invalid, ignoring."); + return 0; + } + + d = get_crypto_device(uuid); + if (!d) + return log_oom(); + + keyspec = value + n + 1; + c = strrchr(keyspec, ':'); + if (c) { + *c = '\0'; + keyfile = strdup(keyspec); + keydev = strdup(c + 1); + + if (!keyfile || !keydev) + return log_oom(); + } else { + /* No keydev specified */ + keyfile = strdup(keyspec); + if (!keyfile) + return log_oom(); + } + + free_and_replace(d->keyfile, keyfile); + free_and_replace(d->keydev, keydev); + } else if (streq(key, "luks.name")) { + + if (proc_cmdline_value_missing(key, value)) + return 0; + + r = sscanf(value, "%m[0-9a-fA-F-]=%ms", &uuid, &uuid_value); + if (r == 2) { + d = get_crypto_device(uuid); + if (!d) + return log_oom(); + + d->create = arg_whitelist = true; + + free_and_replace(d->name, uuid_value); + } else + log_warning("Failed to parse luks name switch %s. Ignoring.", value); + } + + return 0; +} + +static int add_crypttab_devices(void) { + _cleanup_fclose_ FILE *f = NULL; + unsigned crypttab_line = 0; + struct stat st; + int r; + + if (!arg_read_crypttab) + return 0; + + f = fopen("/etc/crypttab", "re"); + if (!f) { + if (errno != ENOENT) + log_error_errno(errno, "Failed to open /etc/crypttab: %m"); + return 0; + } + + (void) __fsetlocking(f, FSETLOCKING_BYCALLER); + + if (fstat(fileno(f), &st) < 0) { + log_error_errno(errno, "Failed to stat /etc/crypttab: %m"); + return 0; + } + + for (;;) { + _cleanup_free_ char *line = NULL, *name = NULL, *device = NULL, *keyfile = NULL, *options = NULL; + crypto_device *d = NULL; + char *l, *uuid; + int k; + + r = read_line(f, LONG_LINE_MAX, &line); + if (r < 0) + return log_error_errno(r, "Failed to read /etc/crypttab: %m"); + if (r == 0) + break; + + crypttab_line++; + + l = strstrip(line); + if (IN_SET(l[0], 0, '#')) + continue; + + k = sscanf(l, "%ms %ms %ms %ms", &name, &device, &keyfile, &options); + if (k < 2 || k > 4) { + log_error("Failed to parse /etc/crypttab:%u, ignoring.", crypttab_line); + continue; + } + + uuid = STARTSWITH_SET(device, "UUID=", "luks-"); + if (!uuid) + uuid = path_startswith(device, "/dev/disk/by-uuid/"); + if (uuid) + d = hashmap_get(arg_disks, uuid); + + if (arg_whitelist && !d) { + log_info("Not creating device '%s' because it was not specified on the kernel command line.", name); + continue; + } + + r = create_disk(name, device, NULL, keyfile, (d && d->options) ? d->options : options); + if (r < 0) + return r; + + if (d) + d->create = false; + } + + return 0; +} + +static int add_proc_cmdline_devices(void) { + int r; + Iterator i; + crypto_device *d; + + HASHMAP_FOREACH(d, arg_disks, i) { + const char *options; + _cleanup_free_ char *device = NULL; + + if (!d->create) + continue; + + if (!d->name) { + d->name = strappend("luks-", d->uuid); + if (!d->name) + return log_oom(); + } + + device = strappend("UUID=", d->uuid); + if (!device) + return log_oom(); + + if (d->options) + options = d->options; + else if (arg_default_options) + options = arg_default_options; + else + options = "timeout=0"; + + r = create_disk(d->name, device, d->keydev, d->keyfile ?: arg_default_keyfile, options); + if (r < 0) + return r; + } + + return 0; +} + +DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(crypt_device_hash_ops, char, string_hash_func, string_compare_func, + crypto_device, crypt_device_free); + +static int run(const char *dest, const char *dest_early, const char *dest_late) { + int r; + + assert_se(arg_dest = dest); + + arg_disks = hashmap_new(&crypt_device_hash_ops); + if (!arg_disks) + return log_oom(); + + r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, PROC_CMDLINE_STRIP_RD_PREFIX); + if (r < 0) + return log_warning_errno(r, "Failed to parse kernel command line: %m"); + + if (!arg_enabled) + return 0; + + r = add_crypttab_devices(); + if (r < 0) + return r; + + r = add_proc_cmdline_devices(); + if (r < 0) + return r; + + return 0; +} + +DEFINE_MAIN_GENERATOR_FUNCTION(run); |