homework: Accept volume key from keyring

This bypasses authentication (i.e. user_record_authenticate) if the
volume key was loaded from the keyring and no secret section is
provided.

This also changes Update() and Resize() to always try and load the
volume key from the keyring. This makes the secret section optional for
these methods while still letting them function (as long as the home
area is active)

test/units/testsuite-46.sh

@@ -89,6 +89,37 @@ inspect test-user
 homectl deactivate test-user
 inspect test-user
 
+# Do some keyring tests, but only on real kernels, since keyring access inside of containers will fail
+# (See: https://github.com/systemd/systemd/issues/17606)
+if ! systemd-detect-virt -cq ; then
+        PASSWORD=xEhErW0ndafV4s homectl activate test-user
+        inspect test-user
+
+        # Key should now be in the keyring
+        homectl update test-user --real-name "Keyring Test"
+        inspect test-user
+
+        # These commands shouldn't use the keyring
+        (! timeout 5s homectl authenticate test-user )
+        (! NEWPASSWORD="foobar" timeout 5s homectl passwd test-user )
+
+        homectl lock test-user
+        inspect test-user
+
+        # Key should be gone from keyring
+        (! timeout 5s homectl update test-user --real-name "Keyring Test 2" )
+
+        PASSWORD=xEhErW0ndafV4s homectl unlock test-user
+        inspect test-user
+
+        # Key should have been re-instantiated into the keyring
+        homectl update test-user --real-name "Keyring Test 3"
+        inspect test-user
+
+        homectl deactivate test-user
+        inspect test-user
+fi
+
 # Do some resize tests, but only if we run on real kernels, as quota inside of containers will fail
 if ! systemd-detect-virt -cq ; then
     # grow while inactive
@@ -150,6 +181,11 @@ if ! systemd-detect-virt -cq ; then
     homectl rebalance
     inspect test-user
     inspect test-user2
+
+    wait_for_state test-user2 active
+    homectl deactivate test-user2
+    wait_for_state test-user2 inactive
+    homectl remove test-user2
 fi
 
 PASSWORD=xEhErW0ndafV4s homectl with test-user -- test ! -f /home/test-user/xyz
@@ -161,13 +197,6 @@ PASSWORD=xEhErW0ndafV4s homectl with test-user -- test -f /home/test-user/xyz
 wait_for_state test-user inactive
 homectl remove test-user
 
-if ! systemd-detect-virt -cq ; then
-    wait_for_state test-user2 active
-    homectl deactivate test-user2
-    wait_for_state test-user2 inactive
-    homectl remove test-user2
-fi
-
 # blob directory tests
 # See docs/USER_RECORD_BLOB_DIRS.md
 checkblob() {