bug#40837: core-updates: webkitgtk web process sandbox incomplete

[Jack Hill <jackhill@jackhill.us>]

Some additional observations:

With my patched webkitgtk, if I set:

PULSE_CLIENTCONFIG=/gnu/store/zc4dsmvdabi00nvisrjhi9w00ff4igs7-client.conf

it does work, which is an improvement compared to without the patch.

I notice that Nix [0] has a similar patch:

"""
diff -ru old/webkitgtk-2.26.0/Source/WebKit/UIProcess/Launcher/glib/BubblewrapLauncher.cpp webkitgtk-2.26.0/Source/WebKit/UIProcess/Launcher/glib/BubblewrapLauncher.cpp
--- old/webkitgtk-2.26.0/Source/WebKit/UIProcess/Launcher/glib/BubblewrapLauncher.cpp	2019-09-09 04:47:07.000000000 -0400
+++ webkitgtk-2.26.0/Source/WebKit/UIProcess/Launcher/glib/BubblewrapLauncher.cpp	2019-09-20 21:14:10.537921173 -0400
@@ -585,7 +585,7 @@
          { SCMP_SYS(keyctl), nullptr },
          { SCMP_SYS(request_key), nullptr },

-        // Scary VM/NUMA ops 
+        // Scary VM/NUMA ops
          { SCMP_SYS(move_pages), nullptr },
          { SCMP_SYS(mbind), nullptr },
          { SCMP_SYS(get_mempolicy), nullptr },
@@ -724,6 +724,10 @@
          "--ro-bind-try", "/usr/local/lib64", "/usr/local/lib64",

          "--ro-bind-try", PKGLIBEXECDIR, PKGLIBEXECDIR,
+
+        // Nix Directories
+        "--ro-bind", "@storeDir@", "@storeDir@",
+        "--ro-bind", "/run/current-system", "/run/current-system",
      };
      // We would have to parse ld config files for more info.
      bindPathVar(sandboxArgs, "LD_LIBRARY_PATH");
"""

[0] https://github.com/NixOS/nixpkgs/blob/465566948393cf533e3617704d1c4ccc34cf3753/pkgs/development/libraries/webkitgtk/fix-bubblewrap-paths.patch

so I wonder if I didn't do the mounts in the right place and or if it is 
becasue I missed /run/current-system.

I'm going to try to adapt the Nix patch to see if that helps.

Best,
Jack