Merge pull request #15713 from poettering/home-discard-when-offline

homed: optionally, issue FITRIM ioctl when logging out
This commit is contained in:
Lennart Poettering 2020-05-07 19:17:48 +02:00 committed by GitHub
commit 7c5137329d
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13 changed files with 208 additions and 29 deletions

1
TODO
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@ -226,7 +226,6 @@ Features:
- rollback when resize fails mid-operation
- GNOME's side for forget key on suspend (requires rework so that lock screen runs outside of uid)
- resize on login?
- fstrim on logout?
- shrink fs on logout?
- update LUKS password on login if we find there's a password that unlocks the JSON record but not the LUKS device.
- create on activate?

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@ -168,6 +168,10 @@ If the UID assigned to a user does not match the owner of the home directory in
the file system, the home directory is automatically and recursively `chown()`ed
to the correct UID.
Depending on the `discard` setting of the user record either the backing
Depending on the `luksDiscard` setting of the user record either the backing
loopback file is `fallocate()`ed during activation, or the mounted file system
is `FITRIM`ed after mounting, to ensure the setting is correctly enforced.
When deactivating a home directory, the file system or block device is trimmed
or extended as configured in the `luksOfflineDiscard` setting of the user
record.

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@ -455,6 +455,10 @@ storage. If false and `luks` storage is used turns this behavior off. In
addition, depending on this setting an `FITRIM` or `fallocate()` operation is
executed to make sure the image matches the selected option.
`luksOfflineDiscard` → A boolean. Similar to `luksDiscard`, it controls whether
to trim/allocate the file system/backing file when deactivating the home
directory.
`luksCipher` → A string, indicating the cipher to use for the LUKS storage mechanism.
`luksCipherMode` → A string, selecting the cipher mode to use for the LUKS storage mechanism.
@ -648,11 +652,12 @@ that may be used in this section are identical to the equally named ones in the
`mountNoDevices`, `mountNoSuid`, `mountNoExecute`, `cifsDomain`,
`cifsUserName`, `cifsService`, `imagePath`, `uid`, `gid`, `memberOf`,
`fileSystemType`, `partitionUuid`, `luksUuid`, `fileSystemUuid`, `luksDiscard`,
`luksCipher`, `luksCipherMode`, `luksVolumeKeySize`, `luksPbkdfHashAlgorithm`,
`luksPbkdfType`, `luksPbkdfTimeCostUSec`, `luksPbkdfMemoryCost`,
`luksPbkdfParallelThreads`, `rateLimitIntervalUSec`, `rateLimitBurst`,
`enforcePasswordPolicy`, `autoLogin`, `stopDelayUSec`, `killProcesses`,
`passwordChangeMinUSec`, `passwordChangeMaxUSec`, `passwordChangeWarnUSec`,
`luksOfflineDiscard`, `luksOfflineDiscard`, `luksCipher`, `luksCipherMode`,
`luksVolumeKeySize`, `luksPbkdfHashAlgorithm`, `luksPbkdfType`,
`luksPbkdfTimeCostUSec`, `luksPbkdfMemoryCost`, `luksPbkdfParallelThreads`,
`rateLimitIntervalUSec`, `rateLimitBurst`, `enforcePasswordPolicy`,
`autoLogin`, `stopDelayUSec`, `killProcesses`, `passwordChangeMinUSec`,
`passwordChangeMaxUSec`, `passwordChangeWarnUSec`,
`passwordChangeInactiveUSec`, `passwordChangeNow`, `pkcs11TokenUri`.
## Fields in the `binding` section

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@ -544,6 +544,16 @@
loopback file) the discard logic defaults to on.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--luks-offline-discard=</option><replaceable>BOOL</replaceable></term>
<listitem><para>Similar to <option>--luks-discard=</option>, controls the trimming of the file
system. However, while <option>--luks-discard=</option> controls what happens when the home directory
is active, <option>--luks-offline-discard=</option> controls what happens when it becomes inactive,
i.e. whether to trim/allocate the storage when deactivating the home directory. This option defaults
to on, to ensure disk space is minimized while a user is not logged in.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--luks-cipher=</option><replaceable>CIPHER</replaceable></term>
<term><option>--luks-cipher-mode=</option><replaceable>MODE</replaceable></term>

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@ -2226,6 +2226,9 @@ static int help(int argc, char *argv[], void *userdata) {
" --fs-type=TYPE File system type to use in case of luks\n"
" storage (ext4, xfs, btrfs)\n"
" --luks-discard=BOOL Whether to use 'discard' feature of file system\n"
" when activated (mounted)\n"
" --luks-offline-discard=BOOL\n"
" Whether to trim file on logout\n"
" --luks-cipher=CIPHER Cipher to use for LUKS encryption\n"
" --luks-cipher-mode=MODE Cipher mode to use for LUKS encryption\n"
" --luks-volume-key-size=BITS\n"
@ -2279,6 +2282,7 @@ static int parse_argv(int argc, char *argv[]) {
ARG_IMAGE_PATH,
ARG_UMASK,
ARG_LUKS_DISCARD,
ARG_LUKS_OFFLINE_DISCARD,
ARG_JSON,
ARG_SETENV,
ARG_TIMEZONE,
@ -2372,6 +2376,7 @@ static int parse_argv(int argc, char *argv[]) {
{ "image-path", required_argument, NULL, ARG_IMAGE_PATH },
{ "fs-type", required_argument, NULL, ARG_FS_TYPE },
{ "luks-discard", required_argument, NULL, ARG_LUKS_DISCARD },
{ "luks-offline-discard", required_argument, NULL, ARG_LUKS_OFFLINE_DISCARD },
{ "luks-cipher", required_argument, NULL, ARG_LUKS_CIPHER },
{ "luks-cipher-mode", required_argument, NULL, ARG_LUKS_CIPHER_MODE },
{ "luks-volume-key-size", required_argument, NULL, ARG_LUKS_VOLUME_KEY_SIZE },
@ -2941,6 +2946,25 @@ static int parse_argv(int argc, char *argv[]) {
break;
case ARG_LUKS_OFFLINE_DISCARD:
if (isempty(optarg)) {
r = drop_from_identity("luksOfflineDiscard");
if (r < 0)
return r;
break;
}
r = parse_boolean(optarg);
if (r < 0)
return log_error_errno(r, "Failed to parse --luks-offline-discard= parameter: %s", optarg);
r = json_variant_set_field_boolean(&arg_identity_extra, "luksOfflineDiscard", r);
if (r < 0)
return log_error_errno(r, "Failed to set offline discard field: %m");
break;
case ARG_LUKS_VOLUME_KEY_SIZE:
case ARG_LUKS_PBKDF_PARALLEL_THREADS:
case ARG_RATE_LIMIT_BURST: {

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@ -1002,6 +1002,8 @@ static int home_start_work(Home *h, const char *verb, UserRecord *hr, UserRecord
if (r < 0)
return r;
if (r == 0) {
const char *homework;
/* Child */
if (setenv("NOTIFY_SOCKET", "/run/systemd/home/notify", 1) < 0) {
@ -1017,7 +1019,11 @@ static int home_start_work(Home *h, const char *verb, UserRecord *hr, UserRecord
stdin_fd = stdout_fd = -1; /* have been invalidated by rearrange_stdio() */
execl(SYSTEMD_HOMEWORK_PATH, SYSTEMD_HOMEWORK_PATH, verb, NULL);
/* Allow overriding the homework path via an environment variable, to make debugging
* easier. */
homework = getenv("SYSTEMD_HOMEWORK_PATH") ?: SYSTEMD_HOMEWORK_PATH;
execl(homework, homework, verb, NULL);
log_error_errno(errno, "Failed to invoke " SYSTEMD_HOMEWORK_PATH ": %m");
_exit(EXIT_FAILURE);
}

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@ -893,19 +893,19 @@ int home_store_header_identity_luks(
return 1;
}
static int run_fitrim(int root_fd) {
int run_fitrim(int root_fd) {
char buf[FORMAT_BYTES_MAX];
struct fstrim_range range = {
.len = UINT64_MAX,
};
/* If discarding is on, discard everything right after mounting, so that the discard setting takes
* effect on activation. */
* effect on activation. (Also, optionally, trim on logout) */
assert(root_fd >= 0);
if (ioctl(root_fd, FITRIM, &range) < 0) {
if (IN_SET(errno, ENOTTY, EOPNOTSUPP, EBADF)) {
if (ERRNO_IS_NOT_SUPPORTED(errno) || errno == EBADF) {
log_debug_errno(errno, "File system does not support FITRIM, not trimming.");
return 0;
}
@ -918,15 +918,32 @@ static int run_fitrim(int root_fd) {
return 1;
}
static int run_fallocate(int backing_fd, const struct stat *st) {
int run_fitrim_by_path(const char *root_path) {
_cleanup_close_ int root_fd = -1;
root_fd = open(root_path, O_RDONLY|O_DIRECTORY|O_CLOEXEC);
if (root_fd < 0)
return log_error_errno(errno, "Failed to open file system '%s' for trimming: %m", root_path);
return run_fitrim(root_fd);
}
int run_fallocate(int backing_fd, const struct stat *st) {
char buf[FORMAT_BYTES_MAX];
struct stat stbuf;
assert(backing_fd >= 0);
assert(st);
/* If discarding is off, let's allocate the whole image before mounting, so that the setting takes
* effect on activation */
if (!st) {
if (fstat(backing_fd, &stbuf) < 0)
return log_error_errno(errno, "Failed to fstat(): %m");
st = &stbuf;
}
if (!S_ISREG(st->st_mode))
return 0;
@ -955,6 +972,16 @@ static int run_fallocate(int backing_fd, const struct stat *st) {
return 1;
}
int run_fallocate_by_path(const char *backing_path) {
_cleanup_close_ int backing_fd = -1;
backing_fd = open(backing_path, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK);
if (backing_fd < 0)
return log_error_errno(errno, "Failed to open '%s' for fallocate(): %m", backing_path);
return run_fallocate(backing_fd, NULL);
}
int home_prepare_luks(
UserRecord *h,
bool already_activated,
@ -1111,7 +1138,7 @@ int home_prepare_luks(
h->luks_volume_key_size,
h->password,
pkcs11_decrypted_passwords ? *pkcs11_decrypted_passwords : NULL,
user_record_luks_discard(h),
user_record_luks_discard(h) || user_record_luks_offline_discard(h),
&cd,
&found_luks_uuid,
&volume_key,
@ -1147,6 +1174,9 @@ int home_prepare_luks(
if (user_record_luks_discard(h))
(void) run_fitrim(root_fd);
setup->image_fd = TAKE_FD(fd);
setup->do_offline_fallocate = !(setup->do_offline_fitrim = user_record_luks_offline_discard(h));
}
setup->loop = TAKE_PTR(loop);
@ -1259,6 +1289,7 @@ int home_activate_luks(
return r;
setup.undo_mount = false;
setup.do_offline_fitrim = false;
loop_device_relinquish(setup.loop);
@ -1267,6 +1298,7 @@ int home_activate_luks(
log_warning_errno(r, "Failed to relinquish DM device, ignoring: %m");
setup.undo_dm = false;
setup.do_offline_fallocate = false;
log_info("Everything completed.");
@ -1279,6 +1311,7 @@ int home_activate_luks(
int home_deactivate_luks(UserRecord *h) {
_cleanup_(crypt_freep) struct crypt_device *cd = NULL;
_cleanup_free_ char *dm_name = NULL, *dm_node = NULL;
bool we_detached;
int r;
/* Note that the DM device and loopback device are set to auto-detach, hence strictly speaking we
@ -1293,23 +1326,45 @@ int home_deactivate_luks(UserRecord *h) {
r = crypt_init_by_name(&cd, dm_name);
if (IN_SET(r, -ENODEV, -EINVAL, -ENOENT)) {
log_debug_errno(r, "LUKS device %s is already detached.", dm_name);
return false;
log_debug_errno(r, "LUKS device %s has already been detached.", dm_name);
we_detached = false;
} else if (r < 0)
return log_error_errno(r, "Failed to initialize cryptsetup context for %s: %m", dm_name);
else {
log_info("Discovered used LUKS device %s.", dm_node);
log_info("Discovered used LUKS device %s.", dm_node);
crypt_set_log_callback(cd, cryptsetup_log_glue, NULL);
crypt_set_log_callback(cd, cryptsetup_log_glue, NULL);
r = crypt_deactivate(cd, dm_name);
if (IN_SET(r, -ENODEV, -EINVAL, -ENOENT)) {
log_debug_errno(r, "LUKS device %s is already detached.", dm_node);
we_detached = false;
} else if (r < 0)
return log_info_errno(r, "LUKS device %s couldn't be deactivated: %m", dm_node);
else {
log_info("LUKS device detaching completed.");
we_detached = true;
}
}
r = crypt_deactivate(cd, dm_name);
if (IN_SET(r, -ENODEV, -EINVAL, -ENOENT))
log_debug_errno(r, "LUKS device %s is already detached.", dm_node);
else if (r < 0)
return log_info_errno(r, "LUKS device %s couldn't be deactivated: %m", dm_node);
if (user_record_luks_offline_discard(h))
log_debug("Not allocating on logout.");
else
(void) run_fallocate_by_path(user_record_image_path(h));
log_info("LUKS device detaching completed.");
return true;
return we_detached;
}
int home_trim_luks(UserRecord *h) {
assert(h);
if (!user_record_luks_offline_discard(h)) {
log_debug("Not trimming on logout.");
return 0;
}
(void) run_fitrim_by_path(user_record_home_directory(h));
return 0;
}
static int run_mkfs(
@ -1918,7 +1973,9 @@ int home_create_luks(
if (asprintf(&disk_uuid_path, "/dev/disk/by-uuid/" SD_ID128_UUID_FORMAT_STR, SD_ID128_FORMAT_VAL(luks_uuid)) < 0)
return log_oom();
if (user_record_luks_discard(h)) {
if (user_record_luks_discard(h) || user_record_luks_offline_discard(h)) {
/* If we want online or offline discard, discard once before we start using things. */
if (ioctl(image_fd, BLKDISCARD, (uint64_t[]) { 0, block_device_size }) < 0)
log_full_errno(errno == EOPNOTSUPP ? LOG_DEBUG : LOG_WARNING, errno,
"Failed to issue full-device BLKDISCARD on device, ignoring: %m");
@ -2004,7 +2061,7 @@ int home_create_luks(
user_record_user_name_and_realm(h),
pkcs11_decrypted_passwords,
effective_passwords,
user_record_luks_discard(h),
user_record_luks_discard(h) || user_record_luks_offline_discard(h),
h,
&cd);
if (r < 0)
@ -2084,6 +2141,12 @@ int home_create_luks(
goto fail;
}
if (user_record_luks_offline_discard(h)) {
r = run_fitrim(root_fd);
if (r < 0)
goto fail;
}
root_fd = safe_close(root_fd);
r = umount_verbose("/run/systemd/user-home-mount");
@ -2102,6 +2165,12 @@ int home_create_luks(
loop = loop_device_unref(loop);
if (!user_record_luks_offline_discard(h)) {
r = run_fallocate(image_fd, NULL /* refresh stat() data */);
if (r < 0)
goto fail;
}
if (disk_uuid_path)
(void) ioctl(image_fd, BLKRRPART, 0);

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@ -9,6 +9,7 @@ int home_prepare_luks(UserRecord *h, bool already_activated, const char *force_i
int home_activate_luks(UserRecord *h, char ***pkcs11_decrypted_passwords, UserRecord **ret_home);
int home_deactivate_luks(UserRecord *h);
int home_trim_luks(UserRecord *h);
int home_store_header_identity_luks(UserRecord *h, HomeSetup *setup, UserRecord *old_home);
@ -36,3 +37,8 @@ static inline uint64_t luks_volume_key_size_convert(struct crypt_device *cd) {
return (uint64_t) k;
}
int run_fitrim(int root_fd);
int run_fitrim_by_path(const char *root_path);
int run_fallocate(int backing_fd, const struct stat *st);
int run_fallocate_by_path(const char *backing_path);

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@ -163,7 +163,15 @@ int home_setup_undo(HomeSetup *setup) {
assert(setup);
setup->root_fd = safe_close(setup->root_fd);
if (setup->root_fd >= 0) {
if (setup->do_offline_fitrim) {
q = run_fitrim(setup->root_fd);
if (q < 0)
r = q;
}
setup->root_fd = safe_close(setup->root_fd);
}
if (setup->undo_mount) {
q = umount_verbose("/run/systemd/user-home-mount");
@ -177,8 +185,20 @@ int home_setup_undo(HomeSetup *setup) {
r = q;
}
if (setup->image_fd >= 0) {
if (setup->do_offline_fallocate) {
q = run_fallocate(setup->image_fd, NULL);
if (q < 0)
r = q;
}
setup->image_fd = safe_close(setup->image_fd);
}
setup->undo_mount = false;
setup->undo_dm = false;
setup->do_offline_fitrim = false;
setup->do_offline_fallocate = false;
setup->dm_name = mfree(setup->dm_name);
setup->dm_node = mfree(setup->dm_node);
@ -666,6 +686,12 @@ static int home_deactivate(UserRecord *h, bool force) {
if (r < 0)
return r;
if (r == USER_TEST_MOUNTED) {
if (user_record_storage(h) == USER_LUKS) {
r = home_trim_luks(h);
if (r < 0)
return r;
}
if (umount2(user_record_home_directory(h), UMOUNT_NOFOLLOW | (force ? MNT_FORCE|MNT_DETACH : 0)) < 0)
return log_error_errno(errno, "Failed to unmount %s: %m", user_record_home_directory(h));

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@ -17,6 +17,7 @@ typedef struct HomeSetup {
LoopDevice *loop;
struct crypt_device *crypt_device;
int root_fd;
int image_fd;
sd_id128_t found_partition_uuid;
sd_id128_t found_luks_uuid;
sd_id128_t found_fs_uuid;
@ -28,6 +29,8 @@ typedef struct HomeSetup {
bool undo_dm;
bool undo_mount;
bool do_offline_fitrim;
bool do_offline_fallocate;
uint64_t partition_offset;
uint64_t partition_size;
@ -36,6 +39,7 @@ typedef struct HomeSetup {
#define HOME_SETUP_INIT \
{ \
.root_fd = -1, \
.image_fd = -1, \
.partition_offset = UINT64_MAX, \
.partition_size = UINT64_MAX, \
}

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@ -279,7 +279,7 @@ void user_record_show(UserRecord *hr, bool show_full_group_info) {
printf(" Access Mode: 0%03oo\n", user_record_access_mode(hr));
if (storage == USER_LUKS) {
printf("LUKS Discard: %s\n", yes_no(user_record_luks_discard(hr)));
printf("LUKS Discard: online=%s offline=%s\n", yes_no(user_record_luks_discard(hr)), yes_no(user_record_luks_offline_discard(hr)));
if (!sd_id128_is_null(hr->luks_uuid))
printf(" LUKS UUID: " SD_ID128_FORMAT_STR "\n", SD_ID128_FORMAT_VAL(hr->luks_uuid));

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@ -52,6 +52,7 @@ UserRecord* user_record_new(void) {
.nodev = true,
.nosuid = true,
.luks_discard = -1,
.luks_offline_discard = -1,
.luks_volume_key_size = UINT64_MAX,
.luks_pbkdf_time_cost_usec = UINT64_MAX,
.luks_pbkdf_memory_cost = UINT64_MAX,
@ -944,6 +945,7 @@ static int dispatch_per_machine(const char *name, JsonVariant *variant, JsonDisp
{ "luksUuid", JSON_VARIANT_STRING, json_dispatch_id128, offsetof(UserRecord, luks_uuid), 0 },
{ "fileSystemUuid", JSON_VARIANT_STRING, json_dispatch_id128, offsetof(UserRecord, file_system_uuid), 0 },
{ "luksDiscard", _JSON_VARIANT_TYPE_INVALID, json_dispatch_tristate, offsetof(UserRecord, luks_discard), 0, },
{ "luksOfflineDiscard", _JSON_VARIANT_TYPE_INVALID, json_dispatch_tristate, offsetof(UserRecord, luks_offline_discard), 0, },
{ "luksCipher", JSON_VARIANT_STRING, json_dispatch_string, offsetof(UserRecord, luks_cipher), JSON_SAFE },
{ "luksCipherMode", JSON_VARIANT_STRING, json_dispatch_string, offsetof(UserRecord, luks_cipher_mode), JSON_SAFE },
{ "luksVolumeKeySize", JSON_VARIANT_UNSIGNED, json_dispatch_uint64, offsetof(UserRecord, luks_volume_key_size), 0 },
@ -1276,6 +1278,7 @@ int user_record_load(UserRecord *h, JsonVariant *v, UserRecordLoadFlags load_fla
{ "luksUuid", JSON_VARIANT_STRING, json_dispatch_id128, offsetof(UserRecord, luks_uuid), 0 },
{ "fileSystemUuid", JSON_VARIANT_STRING, json_dispatch_id128, offsetof(UserRecord, file_system_uuid), 0 },
{ "luksDiscard", _JSON_VARIANT_TYPE_INVALID, json_dispatch_tristate, offsetof(UserRecord, luks_discard), 0 },
{ "luksOfflineDiscard", _JSON_VARIANT_TYPE_INVALID, json_dispatch_tristate, offsetof(UserRecord, luks_offline_discard), 0 },
{ "luksCipher", JSON_VARIANT_STRING, json_dispatch_string, offsetof(UserRecord, luks_cipher), JSON_SAFE },
{ "luksCipherMode", JSON_VARIANT_STRING, json_dispatch_string, offsetof(UserRecord, luks_cipher_mode), JSON_SAFE },
{ "luksVolumeKeySize", JSON_VARIANT_UNSIGNED, json_dispatch_uint64, offsetof(UserRecord, luks_volume_key_size), 0 },
@ -1500,6 +1503,27 @@ bool user_record_luks_discard(UserRecord *h) {
return path_startswith(ip, "/dev/");
}
bool user_record_luks_offline_discard(UserRecord *h) {
const char *ip;
assert(h);
if (h->luks_offline_discard >= 0)
return h->luks_offline_discard;
/* Discard while we are logged out should generally be a good idea, except when operating directly on
* physical media, where we should just bind it to the online discard mode. */
ip = user_record_image_path(h);
if (!ip)
return false;
if (path_startswith(ip, "/dev/"))
return user_record_luks_discard(h);
return true;
}
const char *user_record_luks_cipher(UserRecord *h) {
assert(h);

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@ -261,6 +261,7 @@ typedef struct UserRecord {
sd_id128_t file_system_uuid;
int luks_discard;
int luks_offline_discard;
char *luks_cipher;
char *luks_cipher_mode;
uint64_t luks_volume_key_size;
@ -332,6 +333,7 @@ const char *user_record_cifs_user_name(UserRecord *h);
const char *user_record_shell(UserRecord *h);
const char *user_record_real_name(UserRecord *h);
bool user_record_luks_discard(UserRecord *h);
bool user_record_luks_offline_discard(UserRecord *h);
const char *user_record_luks_cipher(UserRecord *h);
const char *user_record_luks_cipher_mode(UserRecord *h);
uint64_t user_record_luks_volume_key_size(UserRecord *h);