treefile: Add readonly-executables

Same motivation as
7392259332

I think we should encourage removing the writable bits from
executables.  This has happened to me:
https://thomask.sdf.org/blog/2019/11/09/take-care-editing-bash-scripts.html

And not having the writable bit may help prevent hardlink
corruption with OSTree in some cases.

We can't do this by default, but add a convenient treefile option
for it.

This starts out by just doing this for RPMs, but I'll add
a secondary pass which does it during postprocessing soon too.

docs/manual/treefile.md

@@ -100,6 +100,11 @@ It supports the following parameters:
 
     The default is `false` out of conservatism; you likely want to enable this.
 
+ * `readonly-executables`: boolean, optional.  Defaults to `false` (for backcompat).
+    If enabled, rpm-ostree will remove the write bit from all executables.
+
+    The default is `false` out of conservatism; you likely want to enable this.
+
  * `remove-files`: Array of files to delete from the generated tree.
 
  * `remove-from-packages`: Array, optional: Delete from specified packages

rust/src/treefile.rs

@@ -297,6 +297,7 @@ fn treefile_merge(dest: &mut TreeComposeConfig, src: &mut TreeComposeConfig) {
         container,
         recommends,
         cliwrap,
+        readonly_executables,
         documentation,
         boot_location,
         tmp_is_dir,
@@ -691,6 +692,9 @@ struct TreeComposeConfig {
     initramfs_args: Option<Vec<String>>,
     #[serde(skip_serializing_if = "Option::is_none")]
     cliwrap: Option<bool>,
+    #[serde(rename = "readonly-executables")]
+    #[serde(skip_serializing_if = "Option::is_none")]
+    readonly_executables: Option<bool>,
 
     // Tree layout options
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -1379,6 +1383,12 @@ mod ffi {
         tf.parsed.cliwrap.unwrap_or(false)
     }
 
+    #[no_mangle]
+    pub extern "C" fn ror_treefile_get_readonly_executables(tf: *mut Treefile) -> bool {
+        let tf = ref_from_raw_ptr(tf);
+        tf.parsed.readonly_executables.unwrap_or(false)
+    }
+
     #[no_mangle]
     pub extern "C" fn ror_treefile_free(tf: *mut Treefile) {
         if tf.is_null() {

src/libpriv/rpmostree-core.c

@@ -2541,6 +2541,9 @@ start_async_import_one_package (RpmOstreeContext *self, DnfPackage *pkg,
       flags |= RPMOSTREE_IMPORTER_FLAGS_NODOCS;
   }
 
+  if (self->treefile_rs && ror_treefile_get_readonly_executables (self->treefile_rs))
+    flags |= RPMOSTREE_IMPORTER_FLAGS_RO_EXECUTABLES;
+
   /* TODO - tweak the unpacker flags for containers */
   OstreeRepo *ostreerepo = get_pkgcache_repo (self);
   g_autoptr(RpmOstreeImporter) unpacker =

src/libpriv/rpmostree-importer.c

@@ -719,6 +719,18 @@ compose_filter_cb (OstreeRepo         *repo,
 
   ensure_directories_user_writable (file_info);
 
+  /* See similar code in `ostree commit` - https://github.com/ostreedev/ostree/pull/2091/commits/7392259332e00c33ed45b904deabde08f4da3e3c */
+  if ((self->flags & RPMOSTREE_IMPORTER_FLAGS_RO_EXECUTABLES) > 0 &&
+      g_file_info_get_file_type (file_info) == G_FILE_TYPE_REGULAR)
+    {
+      guint32 mode = g_file_info_get_attribute_uint32 (file_info, "unix::mode");
+      if (mode & (S_IXUSR | S_IXGRP | S_IXOTH))
+        {
+          mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
+          g_file_info_set_attribute_uint32 (file_info, "unix::mode", mode);
+        }
+    }
+
   return OSTREE_REPO_COMMIT_FILTER_ALLOW;
 }
 

src/libpriv/rpmostree-importer.h

@@ -40,10 +40,12 @@ G_DEFINE_AUTOPTR_CLEANUP_FUNC (RpmOstreeImporter, g_object_unref)
  * RpmOstreeImporterFlags:
  * @RPMOSTREE_IMPORTER_FLAGS_SKIP_EXTRANEOUS: Skip files/directories outside of supported ostree-compliant paths rather than erroring out
  * @RPMOSTREE_IMPORTER_FLAGS_NODOCS: Skip documentation files
+ * @RPMOSTREE_IMPORTER_FLAGS_RO_EXECUTABLES: Make executable files readonly
  */
 typedef enum {
   RPMOSTREE_IMPORTER_FLAGS_SKIP_EXTRANEOUS =  (1 << 0),
   RPMOSTREE_IMPORTER_FLAGS_NODOCS =  (1 << 1),
+  RPMOSTREE_IMPORTER_FLAGS_RO_EXECUTABLES =  (1 << 2),
 } RpmOstreeImporterFlags;
 
 RpmOstreeImporter*

tests/compose/test-misc-tweaks.sh

@@ -20,12 +20,14 @@ treefile_append "packages" '["foobar"]'
 cat > config/documentation.yaml <<'EOF'
 documentation: true
 EOF
-cat > config/recommends.yaml <<'EOF'
+cat > config/other.yaml <<'EOF'
 recommends: true
+readonly-executables: true
 EOF
-treefile_append "include" '["documentation.yaml", "recommends.yaml"]'
-treefile_del 'recommends'
-treefile_del 'documentation'
+treefile_append "include" '["documentation.yaml", "other.yaml"]'
+for x in 'recommends' 'documentation' 'readonly-executables'; do
+  treefile_del "$x"
+done
 
 # Test blacklists
 treefile_append "exclude-packages" '["somenonexistent-package", "gnome-shell"]'
@@ -169,6 +171,11 @@ ostree --repo=${repo} cat ${treeref} /usr/bin/ls > ls.txt
 assert_file_has_content ls.txt '^sweet new ls binary$'
 echo "ok layers"
 
+# Test readonly-executables
+ostree --repo=${repo} ls ${treeref} /usr/bin/bash > ls.txt
+assert_file_has_content ls.txt '^-00555 .*/usr/bin/bash$'
+echo "ok readonly-executables"
+
 # Check that add-files with bad paths are rejected
 treefile_append "add-files" '[["foo.txt", "/var/lib/foo.txt"]]'