Merge pull request #21135 from poettering/homed-uidmap

homed: make use of uidmap'ped mounts for avoiding recursive chown()

TODO

@@ -1279,8 +1279,6 @@ Features:
   - support new FS_IOC_ADD_ENCRYPTION_KEY ioctl for setting up fscrypt
   - maybe pre-create ~/.cache as subvol so that it can have separate quota
     easily?
-  - if kernel 5.12 uid mapping mounts exist, use that instead of recursive
-    chowns.
   - add a switch to homectl (maybe called --first-boot) where it will check if
     any non-system users exist, and if not prompts interactively for basic user
     info, mimicking systemd-firstboot. Then, place this in a service that runs

src/home/homework-cifs.c

@@ -159,7 +159,7 @@ int home_activate_cifs(
         assert_se(hdo = user_record_home_directory(h));
         hd = strdupa_safe(hdo); /* copy the string out, since it might change later in the home record object */
 
-        r = home_setup(h, 0, cache, setup, &header_home);
+        r = home_setup(h, 0, setup, cache, &header_home);
         if (r < 0)
                 return r;
 

src/home/homework-directory.c

@@ -74,7 +74,7 @@ int home_activate_directory(
         assert_se(hdo = user_record_home_directory(h));
         hd = strdupa_safe(hdo);
 
-        r = home_setup(h, 0, cache, setup, &header_home);
+        r = home_setup(h, 0, setup, cache, &header_home);
         if (r < 0)
                 return r;
 
@@ -259,8 +259,8 @@ int home_create_directory_or_subvolume(UserRecord *h, HomeSetup *setup, UserReco
 int home_resize_directory(
                 UserRecord *h,
                 HomeSetupFlags flags,
-                PasswordCache *cache,
                 HomeSetup *setup,
+                PasswordCache *cache,
                 UserRecord **ret_home) {
 
         _cleanup_(user_record_unrefp) UserRecord *embedded_home = NULL, *new_home = NULL;
@@ -271,7 +271,7 @@ int home_resize_directory(
         assert(ret_home);
         assert(IN_SET(user_record_storage(h), USER_DIRECTORY, USER_SUBVOLUME, USER_FSCRYPT));
 
-        r = home_setup(h, flags, cache, setup, NULL);
+        r = home_setup(h, flags, setup, cache, NULL);
         if (r < 0)
                 return r;
 

src/home/homework-directory.h

@@ -7,4 +7,4 @@
 int home_setup_directory(UserRecord *h, HomeSetup *setup);
 int home_activate_directory(UserRecord *h, HomeSetup *setup, PasswordCache *cache, UserRecord **ret_home);
 int home_create_directory_or_subvolume(UserRecord *h, HomeSetup *setup, UserRecord **ret_home);
-int home_resize_directory(UserRecord *h, HomeSetupFlags flags, PasswordCache *cache, HomeSetup *setup, UserRecord **ret_home);
+int home_resize_directory(UserRecord *h, HomeSetupFlags flags, HomeSetup *setup, PasswordCache *cache, UserRecord **ret_home);

src/home/homework-fscrypt.c

@@ -282,8 +282,8 @@ static int fscrypt_setup(
 
 int home_setup_fscrypt(
                 UserRecord *h,
-                const PasswordCache *cache,
-                HomeSetup *setup) {
+                HomeSetup *setup,
+                const PasswordCache *cache) {
 
         _cleanup_(erase_and_freep) void *volume_key = NULL;
         struct fscrypt_policy policy = {};

src/home/homework-fscrypt.h

@@ -4,7 +4,7 @@
 #include "homework.h"
 #include "user-record.h"
 
-int home_setup_fscrypt(UserRecord *h, const PasswordCache *cache, HomeSetup *setup);
+int home_setup_fscrypt(UserRecord *h, HomeSetup *setup, const PasswordCache *cache);
 
 int home_create_fscrypt(UserRecord *h, HomeSetup *setup, char **effective_passwords, UserRecord **ret_home);
 

src/home/homework-luks.h

@@ -5,24 +5,24 @@
 #include "homework.h"
 #include "user-record.h"
 
-int home_setup_luks(UserRecord *h, HomeSetupFlags flags, const char *force_image_path, PasswordCache *cache, HomeSetup *setup, UserRecord **ret_luks_home);
+int home_setup_luks(UserRecord *h, HomeSetupFlags flags, const char *force_image_path, HomeSetup *setup, PasswordCache *cache, UserRecord **ret_luks_home);
 
 int home_activate_luks(UserRecord *h, HomeSetup *setup, PasswordCache *cache, UserRecord **ret_home);
-int home_deactivate_luks(UserRecord *h);
+int home_deactivate_luks(UserRecord *h, HomeSetup *setup);
 int home_trim_luks(UserRecord *h);
 
 int home_store_header_identity_luks(UserRecord *h, HomeSetup *setup, UserRecord *old_home);
 
-int home_create_luks(UserRecord *h, const PasswordCache *cache, char **effective_passwords, UserRecord **ret_home);
+int home_create_luks(UserRecord *h, HomeSetup *setup, const PasswordCache *cache, char **effective_passwords, UserRecord **ret_home);
 
 int home_get_state_luks(UserRecord *h, HomeSetup *setup);
 
-int home_resize_luks(UserRecord *h, HomeSetupFlags flags, PasswordCache *cache, HomeSetup *setup, UserRecord **ret_home);
+int home_resize_luks(UserRecord *h, HomeSetupFlags flags, HomeSetup *setup, PasswordCache *cache, UserRecord **ret_home);
 
 int home_passwd_luks(UserRecord *h, HomeSetup *setup, const PasswordCache *cache, char **effective_passwords);
 
-int home_lock_luks(UserRecord *h);
-int home_unlock_luks(UserRecord *h, const PasswordCache *cache);
+int home_lock_luks(UserRecord *h, HomeSetup *setup);
+int home_unlock_luks(UserRecord *h, HomeSetup *setup, const PasswordCache *cache);
 
 static inline uint64_t luks_volume_key_size_convert(struct crypt_device *cd) {
         int k;

src/home/homework-mount.c

@@ -84,7 +84,17 @@ int home_unshare_and_mount(const char *node, const char *fstype, bool discard, u
         if (r < 0)
                 return r;
 
-        return home_mount_node(node, fstype, discard, flags);
+        r = home_mount_node(node, fstype, discard, flags);
+        if (r < 0)
+                return r;
+
+        r = mount_nofollow_verbose(LOG_ERR, NULL, HOME_RUNTIME_WORK_DIR, NULL, MS_PRIVATE, NULL);
+        if (r < 0) {
+                (void) umount_verbose(LOG_ERR, HOME_RUNTIME_WORK_DIR, UMOUNT_NOFOLLOW);
+                return r;
+        }
+
+        return 0;
 }
 
 int home_move_mount(const char *mount_suffix, const char *target) {
@@ -111,9 +121,9 @@ int home_move_mount(const char *mount_suffix, const char *target) {
         if (r < 0)
                 return r;
 
-        r = umount_verbose(LOG_ERR, HOME_RUNTIME_WORK_DIR, UMOUNT_NOFOLLOW);
+        r = umount_recursive(HOME_RUNTIME_WORK_DIR, 0);
         if (r < 0)
-                return r;
+                return log_error_errno(r, "Failed to unmount %s: %m", HOME_RUNTIME_WORK_DIR);
 
         log_info("Moving to final mount point %s completed.", target);
         return 0;

src/home/homework.c

@@ -306,14 +306,46 @@ int home_setup_undo_mount(HomeSetup *setup, int level) {
         if (!setup->undo_mount)
                 return 0;
 
-        r = umount_verbose(level, HOME_RUNTIME_WORK_DIR, UMOUNT_NOFOLLOW);
-        if (r < 0)
-                return r;
+        r = umount_recursive(HOME_RUNTIME_WORK_DIR, 0);
+        if (r < 0) {
+                if (level >= LOG_DEBUG) /* umount_recursive() does debug level logging anyway, no need to
+                                         * repeat that here */
+                        return r;
+
+                /* If a higher log level is requested, the generate a non-debug mesage here too. */
+                return log_full_errno(level, r, "Failed to unmount mount tree below %s: %m", HOME_RUNTIME_WORK_DIR);
+        }
 
         setup->undo_mount = false;
         return 1;
 }
 
+int home_setup_undo_dm(HomeSetup *setup, int level) {
+        int r, ret;
+
+        assert(setup);
+
+        if (setup->undo_dm) {
+                assert(setup->crypt_device);
+                assert(setup->dm_name);
+
+                r = sym_crypt_deactivate_by_name(setup->crypt_device, setup->dm_name, 0);
+                if (r < 0)
+                        return log_full_errno(level, r, "Failed to deactivate LUKS device: %m");
+
+                setup->undo_dm = false;
+                ret = 1;
+        } else
+                ret = 0;
+
+        if (setup->crypt_device) {
+                sym_crypt_free(setup->crypt_device);
+                setup->crypt_device = NULL;
+        }
+
+        return ret;
+}
+
 int home_setup_done(HomeSetup *setup) {
         int r = 0, q;
 
@@ -336,11 +368,9 @@ int home_setup_done(HomeSetup *setup) {
         if (q < 0)
                 r = q;
 
-        if (setup->undo_dm && setup->crypt_device && setup->dm_name) {
-                q = sym_crypt_deactivate_by_name(setup->crypt_device, setup->dm_name, 0);
-                if (q < 0)
-                        r = q;
-        }
+        q = home_setup_undo_dm(setup, LOG_DEBUG);
+        if (q < 0)
+                r = q;
 
         if (setup->image_fd >= 0) {
                 if (setup->do_offline_fallocate) {
@@ -358,6 +388,14 @@ int home_setup_done(HomeSetup *setup) {
                 setup->image_fd = safe_close(setup->image_fd);
         }
 
+        if (setup->temporary_image_path) {
+                if (unlink(setup->temporary_image_path) < 0)
+                        log_debug_errno(errno, "Failed to remove temporary image file '%s', ignoring: %m",
+                                        setup->temporary_image_path);
+
+                setup->temporary_image_path = mfree(setup->temporary_image_path);
+        }
+
         setup->undo_mount = false;
         setup->undo_dm = false;
         setup->do_offline_fitrim = false;
@@ -368,10 +406,6 @@ int home_setup_done(HomeSetup *setup) {
         setup->dm_node = mfree(setup->dm_node);
 
         setup->loop = loop_device_unref(setup->loop);
-        if (setup->crypt_device) {
-                sym_crypt_free(setup->crypt_device);
-                setup->crypt_device = NULL;
-        }
 
         setup->volume_key = erase_and_free(setup->volume_key);
         setup->volume_key_size = 0;
@@ -387,8 +421,8 @@ int home_setup_done(HomeSetup *setup) {
 int home_setup(
                 UserRecord *h,
                 HomeSetupFlags flags,
-                PasswordCache *cache,
                 HomeSetup *setup,
+                PasswordCache *cache,
                 UserRecord **ret_header_home) {
 
         int r;
@@ -409,7 +443,7 @@ int home_setup(
         switch (user_record_storage(h)) {
 
         case USER_LUKS:
-                return home_setup_luks(h, flags, NULL, cache, setup, ret_header_home);
+                return home_setup_luks(h, flags, NULL, setup, cache, ret_header_home);
 
         case USER_SUBVOLUME:
         case USER_DIRECTORY:
@@ -417,7 +451,7 @@ int home_setup(
                 break;
 
         case USER_FSCRYPT:
-                r = home_setup_fscrypt(h, cache, setup);
+                r = home_setup_fscrypt(h, setup, cache);
                 break;
 
         case USER_CIFS:
@@ -883,6 +917,7 @@ static int home_activate(UserRecord *h, UserRecord **ret_home) {
 }
 
 static int home_deactivate(UserRecord *h, bool force) {
+        _cleanup_(home_setup_done) HomeSetup setup = HOME_SETUP_INIT;
         bool done = false;
         int r;
 
@@ -919,7 +954,7 @@ static int home_deactivate(UserRecord *h, bool force) {
                 log_info("Directory %s is already unmounted.", user_record_home_directory(h));
 
         if (user_record_storage(h) == USER_LUKS) {
-                r = home_deactivate_luks(h);
+                r = home_deactivate_luks(h, &setup);
                 if (r < 0)
                         return r;
                 if (r > 0)
@@ -1279,7 +1314,7 @@ static int home_create(UserRecord *h, UserRecord **ret_home) {
         switch (user_record_storage(h)) {
 
         case USER_LUKS:
-                r = home_create_luks(h, &cache, effective_passwords, &new_home);
+                r = home_create_luks(h, &setup, &cache, effective_passwords, &new_home);
                 break;
 
         case USER_DIRECTORY:
@@ -1500,7 +1535,7 @@ static int home_update(UserRecord *h, UserRecord **ret) {
         if (r < 0)
                 return r;
 
-        r = home_setup(h, flags, &cache, &setup, &header_home);
+        r = home_setup(h, flags, &setup, &cache, &header_home);
         if (r < 0)
                 return r;
 
@@ -1558,12 +1593,12 @@ static int home_resize(UserRecord *h, UserRecord **ret) {
         switch (user_record_storage(h)) {
 
         case USER_LUKS:
-                return home_resize_luks(h, flags, &cache, &setup, ret);
+                return home_resize_luks(h, flags, &setup, &cache, ret);
 
         case USER_DIRECTORY:
         case USER_SUBVOLUME:
         case USER_FSCRYPT:
-                return home_resize_directory(h, flags, &cache, &setup, ret);
+                return home_resize_directory(h, flags, &setup, &cache, ret);
 
         default:
                 return log_error_errno(SYNTHETIC_ERRNO(ENOTTY), "Resizing home directories of type '%s' currently not supported.", user_storage_to_string(user_record_storage(h)));
@@ -1592,7 +1627,7 @@ static int home_passwd(UserRecord *h, UserRecord **ret_home) {
         if (r < 0)
                 return r;
 
-        r = home_setup(h, flags, &cache, &setup, &header_home);
+        r = home_setup(h, flags, &setup, &cache, &header_home);
         if (r < 0)
                 return r;
 
@@ -1662,7 +1697,7 @@ static int home_inspect(UserRecord *h, UserRecord **ret_home) {
         if (r < 0)
                 return r;
 
-        r = home_setup(h, flags, &cache, &setup, &header_home);
+        r = home_setup(h, flags, &setup, &cache, &header_home);
         if (r < 0)
                 return r;
 
@@ -1685,6 +1720,7 @@ static int home_inspect(UserRecord *h, UserRecord **ret_home) {
 }
 
 static int home_lock(UserRecord *h) {
+        _cleanup_(home_setup_done) HomeSetup setup = HOME_SETUP_INIT;
         int r;
 
         assert(h);
@@ -1700,7 +1736,7 @@ static int home_lock(UserRecord *h) {
         if (r != USER_TEST_MOUNTED)
                 return log_error_errno(SYNTHETIC_ERRNO(ENOEXEC), "Home directory of %s is not mounted, can't lock.", h->user_name);
 
-        r = home_lock_luks(h);
+        r = home_lock_luks(h, &setup);
         if (r < 0)
                 return r;
 
@@ -1709,6 +1745,7 @@ static int home_lock(UserRecord *h) {
 }
 
 static int home_unlock(UserRecord *h) {
+        _cleanup_(home_setup_done) HomeSetup setup = HOME_SETUP_INIT;
         _cleanup_(password_cache_free) PasswordCache cache = {};
         int r;
 
@@ -1726,7 +1763,7 @@ static int home_unlock(UserRecord *h) {
         if (r < 0)
                 return r;
 
-        r = home_unlock_luks(h, &cache);
+        r = home_unlock_luks(h, &setup, &cache);
         if (r < 0)
                 return r;
 

src/home/homework.h

@@ -39,6 +39,8 @@ typedef struct HomeSetup {
         uint64_t partition_size;
 
         char *mount_suffix;           /* The directory to use as home dir is this path below /run/systemd/user-home-mount */
+
+        char *temporary_image_path;
 } HomeSetup;
 
 typedef struct PasswordCache {
@@ -76,8 +78,9 @@ typedef enum HomeSetupFlags {
 int home_setup_done(HomeSetup *setup);
 
 int home_setup_undo_mount(HomeSetup *setup, int level);
+int home_setup_undo_dm(HomeSetup *setup, int level);
 
-int home_setup(UserRecord *h, HomeSetupFlags flags, PasswordCache *cache, HomeSetup *setup, UserRecord **ret_header_home);
+int home_setup(UserRecord *h, HomeSetupFlags flags, HomeSetup *setup, PasswordCache *cache, UserRecord **ret_header_home);
 
 int home_refresh(UserRecord *h, HomeSetup *setup, UserRecord *header_home, PasswordCache *cache, struct statfs *ret_statfs, UserRecord **ret_new_home);