core/namespace: honor MountEntry.read_only, .options, and so on in static entries

Otherwise, ProtectHome=tmpfs makes /home/ and friends not read-only.
Also, mount options for /run/ specified in MountAPIVFS=yes are not
applied.

The function append_static_mounts() was introduced in
5327c91, but at that time, there were
neither .read_only nor .options in the struct. But, when later the
struct is extended, the function was not updated and they were not
copied from the static table.
The fields has been used in static tables since
e4da7d8, and also in
94293d6.

Fixes #34825.

(cherry picked from commit 0cc496b)
(cherry picked from commit dc44fd6)

Author: yuwata

src/core/namespace.c

@@ -656,11 +656,16 @@ static int append_static_mounts(MountList *ml, const MountEntry *mounts, size_t
                 if (!me)
                         return log_oom_debug();
 
-                *me = (MountEntry) {
-                        .path_const = mount_entry_path(m),
-                        .mode = m->mode,
-                        .ignore = m->ignore || ignore_protect,
-                };
+                /* No dynamic values allowed. */
+                assert(m->path_const);
+                assert(!m->path_malloc);
+                assert(!m->unprefixed_path_malloc);
+                assert(!m->source_malloc);
+                assert(!m->options_malloc);
+                assert(!m->overlay_layers);
+
+                *me = *m;
+                me->ignore = me->ignore || ignore_protect;
         }
 
         return 0;

test/units/testsuite-07.exec-context.sh

@@ -46,13 +46,22 @@ if [[ -z "${COVERAGE_BUILD_DIR:-}" ]]; then
         bash -xec "test ! -w /home; test ! -w /root; test ! -w /run/user; test ! -e $MARK"
     systemd-run --wait --pipe -p ProtectHome=read-only \
         bash -xec "test ! -w /home; test ! -w /root; test ! -w /run/user; test -e $MARK"
-    systemd-run --wait --pipe -p ProtectHome=tmpfs \
-        bash -xec "test -w /home; test -w /root; test -w /run/user; test ! -e $MARK"
+    systemd-run --wait --pipe -p ProtectHome=tmpfs -p TemporaryFileSystem=/home/foo \
+        bash -xec "test ! -w /home; test ! -w /root; test ! -w /run/user; test ! -e $MARK; test -w /home/foo"
     systemd-run --wait --pipe -p ProtectHome=no \
         bash -xec "test -w /home; test -w /root; test -w /run/user; test -e $MARK"
     rm -f "$MARK"
 fi
 
+systemd-run --wait --pipe -p PrivateMounts=true -p MountAPIVFS=yes \
+    bash -xec '[[ "$(findmnt --mountpoint /proc --noheadings -o FSTYPE)" == proc ]];
+               [[ "$$(findmnt --mountpoint /dev --noheadings -o FSTYPE)" =~ (devtmpfs|tmpfs) ]];
+               [[ "$$(findmnt --mountpoint /sys --noheadings -o FSTYPE)" =~ (sysfs|tmpfs) ]];
+               [[ "$$(findmnt --mountpoint /run --noheadings -o FSTYPE)" == tmpfs ]];
+               [[ "$$(findmnt --mountpoint /run --noheadings -o VFS-OPTIONS)" =~ rw ]];
+               [[ "$$(findmnt --mountpoint /run --noheadings -o VFS-OPTIONS)" =~ nosuid ]];
+               [[ "$$(findmnt --mountpoint /run --noheadings -o VFS-OPTIONS)" =~ nodev ]]'
+
 if proc_supports_option "hidepid=off"; then
     systemd-run --wait --pipe -p ProtectProc=noaccess -p User=testuser \
         bash -xec 'test -e /proc/1; test ! -r /proc/1; test -r /proc/$$$$/comm'