[gnome-software/1701-permissions-context-tile-says-has-access-to-no-files-even-if-flatpak-app-has-access-to: 16/21] flatpak: Restructure how filesystem permissions are calculated

[Milan Crha <mcrha src gnome org>]

commit cd97c676e046e78c2f6ca2261638538938bfb461
Author: Milan Crha <mcrha redhat com>
Date:   Wed Apr 13 16:54:59 2022 +0200

    flatpak: Restructure how filesystem permissions are calculated
    
    This does no functional change, it only allows to detect whether there
    are any leftover (unchecked) filesystem permissions, which will be
    useful in a follow up commit.

 plugins/flatpak/gs-flatpak.c | 48 ++++++++++++++++++++++++++++----------------
 1 file changed, 31 insertions(+), 17 deletions(-)
---
diff --git a/plugins/flatpak/gs-flatpak.c b/plugins/flatpak/gs-flatpak.c
index 71d628035..bd7f4282f 100644
--- a/plugins/flatpak/gs-flatpak.c
+++ b/plugins/flatpak/gs-flatpak.c
@@ -241,23 +241,37 @@ perms_from_metadata (GKeyFile *keyfile)
        g_strfreev (strv);
 
        strv = g_key_file_get_string_list (keyfile, "Context", "filesystems", NULL, NULL);
-       if (strv != NULL && (g_strv_contains ((const gchar * const *)strv, "home") ||
-                            g_strv_contains ((const gchar * const *)strv, "home:rw")))
-               permissions |= GS_APP_PERMISSIONS_HOME_FULL;
-       else if (strv != NULL && g_strv_contains ((const gchar * const *)strv, "home:ro"))
-               permissions |= GS_APP_PERMISSIONS_HOME_READ;
-       if (strv != NULL && (g_strv_contains ((const gchar * const *)strv, "host") ||
-                            g_strv_contains ((const gchar * const *)strv, "host:rw")))
-               permissions |= GS_APP_PERMISSIONS_FILESYSTEM_FULL;
-       else if (strv != NULL && g_strv_contains ((const gchar * const *)strv, "host:ro"))
-               permissions |= GS_APP_PERMISSIONS_FILESYSTEM_READ;
-       if (strv != NULL && (g_strv_contains ((const gchar * const *)strv, "xdg-download") ||
-                            g_strv_contains ((const gchar * const *)strv, "xdg-download:rw")))
-               permissions |= GS_APP_PERMISSIONS_DOWNLOADS_FULL;
-       else if (strv != NULL && g_strv_contains ((const gchar * const *)strv, "xdg-download:ro"))
-               permissions |= GS_APP_PERMISSIONS_DOWNLOADS_READ;
-       if (strv != NULL && g_strv_contains ((const gchar * const *)strv, 
"xdg-data/flatpak/overrides:create"))
-               permissions |= GS_APP_PERMISSIONS_ESCAPE_SANDBOX;
+       if (strv != NULL) {
+               const struct {
+                       const gchar *key;
+                       GsAppPermissions perm;
+               } filesystems_access[] = {
+                       /* Reference: 
https://docs.flatpak.org/en/latest/flatpak-command-reference.html#idm45858571325264 */
+                       { "home", GS_APP_PERMISSIONS_HOME_FULL },
+                       { "home:rw", GS_APP_PERMISSIONS_HOME_FULL },
+                       { "home:ro", GS_APP_PERMISSIONS_HOME_READ },
+                       { "host", GS_APP_PERMISSIONS_FILESYSTEM_FULL },
+                       { "host:rw", GS_APP_PERMISSIONS_FILESYSTEM_FULL },
+                       { "host:ro", GS_APP_PERMISSIONS_FILESYSTEM_READ },
+                       { "xdg-download", GS_APP_PERMISSIONS_DOWNLOADS_FULL },
+                       { "xdg-download:rw", GS_APP_PERMISSIONS_DOWNLOADS_FULL },
+                       { "xdg-download:ro", GS_APP_PERMISSIONS_DOWNLOADS_READ },
+                       { "xdg-data/flatpak/overrides:create", GS_APP_PERMISSIONS_ESCAPE_SANDBOX }
+               };
+
+               for (guint i = 0; i < G_N_ELEMENTS (filesystems_access); i++) {
+                       if (g_strv_contains ((const gchar * const *) strv, filesystems_access[i].key)) {
+                               permissions |= filesystems_access[i].perm;
+                       }
+               }
+
+               if ((permissions & GS_APP_PERMISSIONS_HOME_FULL) != 0)
+                       permissions = permissions & ~GS_APP_PERMISSIONS_HOME_READ;
+               if ((permissions & GS_APP_PERMISSIONS_FILESYSTEM_FULL) != 0)
+                       permissions = permissions & ~GS_APP_PERMISSIONS_FILESYSTEM_READ;
+               if ((permissions & GS_APP_PERMISSIONS_DOWNLOADS_FULL) != 0)
+                       permissions = permissions & ~GS_APP_PERMISSIONS_DOWNLOADS_READ;
+       }
        g_strfreev (strv);
 
        str = g_key_file_get_string (keyfile, "Session Bus Policy", "ca.desrt.dconf", NULL);