Create subsession and `apps_rw` directories with

[subsession_uid]:system_share UID:GID

Change-Id: Ib1f8d18d715ba6ff52c97cfe78c56d00ae2e9d37

2 files changed, 16 insertions, 3 deletions

diff --git a/sessiond/src/fs_helpers.cpp b/sessiond/src/fs_helpers.cpp
index 8c68a20..614f3b1 100644
--- a/sessiond/src/fs_helpers.cpp
+++ b/sessiond/src/fs_helpers.cpp
@@ -135,14 +135,23 @@ int fs_helpers::get_gid_from_name(std::string_view group_name)
 	std::unique_ptr<char[]> str_grp_buf(new char[max_grp_buf_size]);
 
 	group pass_grp_buf, *pass_grp_ptr;
-	getgrnam_r(main_dir_group.data(), &pass_grp_buf, str_grp_buf.get(), max_grp_buf_size, &pass_grp_ptr);
+	getgrnam_r(group_name.data(), &pass_grp_buf, str_grp_buf.get(), max_grp_buf_size, &pass_grp_ptr);
 	if (!pass_grp_ptr)
 		throw std::runtime_error("Couldn't get Unix gid for `"s
-			+ main_dir_group.data()
+			+ group_name.data()
 			+ "` group");
 	return pass_grp_ptr->gr_gid;
 }
 
+void fs_helpers::change_owner_and_group(std::string_view path, const int session_uid, const int group_id)
+{
+	if (chown(path.data(), session_uid, group_id) == -1)
+		throw std::system_error(errno, std::system_category(),
+			"Couldn't set owner/group of the `"s
+			+ path.data()
+			+ "` file/directory");
+}
+
 // Create `$HOME/subsession` directory if it doesn't exist
 void fs_helpers::create_main_subdirectory(const int session_uid, std::string_view main_dir)
 {
@@ -200,6 +209,9 @@ void fs_helpers::add_user_subsession(const int session_uid, const std::string_vi
 
 		fs::create_directory(tmp_subsession_dir);
 
+		int gid = get_gid_from_name(main_dir_group);
+		change_owner_and_group(tmp_subsession_dir, session_uid, gid);
+
 		std::string apps_rw_dir = tmp_subsession_dir + "/apps_rw";
 		fs::path apps_rw_path { apps_rw_dir };
 		std::string source_dir = "/etc/skel/apps_rw";
@@ -224,7 +236,7 @@ void fs_helpers::add_user_subsession(const int session_uid, const std::string_vi
 			copy_smack_attributes(s_path, d_path);
 		}
 		// Last but not least - the `apps_rw` directory itself
-		copy_ownership(source_dir, apps_rw_dir);
+		change_owner_and_group(apps_rw_dir, session_uid, gid);
 		copy_smack_attributes(source_dir, apps_rw_dir);
 
 		// Copy + rename so that the replacement is atomic
diff --git a/sessiond/src/fs_helpers.h b/sessiond/src/fs_helpers.h
index d0772cb..8843a87 100644
--- a/sessiond/src/fs_helpers.h
+++ b/sessiond/src/fs_helpers.h
@@ -15,6 +15,7 @@ namespace fs_helpers
 	fs::path get_subsession_dir_by_uid(const int session_uid);
 
 	void create_main_subdirectory(const int session_uid, std::string_view main_dir);
+	void change_owner_and_group(std::string_view path, const int session_uid, const int group_id);
 	void copy_ownership(std::string_view src_path, std::string_view dest_path);
 	std::string get_smack_label(std::string_view src_path, smack_label_type type);
 	void copy_smack_attributes(std::string_view src_path, std::string_view dest_path);