bug#47628: webkitgtk-2.32.0 fails to launch without /usr/bin

[Mark H Weaver <mhw@netris.org>]

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Hi Efraim,

Efraim Flashner <efraim@flashner.co.il> writes:

> On Thu, Apr 08, 2021 at 11:07:31AM -0400, Mark H Weaver wrote:
>> I suspect that the relevant bit that needs to be changed is line 779 of
>> the following file in the webkitgtk-2.32.0 source code:
>> 
>>   Source/WebKit/UIProcess/Launcher/glib/BubblewrapLauncher.cpp
>> 
>> Most likely, that line can simply be deleted.  Here's the relevant
>> excerpt, with line 779 marked by "==>":
>
> Looking at the other lines above it, we could just change it from
> ro-bind to ro-bind-try.

I expect that would work, but why should we give the sandbox access to
/usr/bin at all?  I took a different approach: I removed access to *all*
of the FHS directories, since they should not be needed for a
Guix-compiled package.

Below, I've attached the patch that I'm currently using successfully on
my private branch of Guix.

What do you think?

     Thanks,
       Mark


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From 4a10e1deb63d1b2227a0bcc60a17ddb9af7b8cc3 Mon Sep 17 00:00:00 2001
From: Mark H Weaver <mhw@netris.org>
Date: Thu, 8 Apr 2021 11:27:55 -0400
Subject: [PATCH] DRAFT: gnu: webkitgtk: Trim system dirs made available to
 sandbox.

* gnu/packages/patches/webkitgtk-share-store.patch: Adjust patch.
---
 .../patches/webkitgtk-share-store.patch       | 46 ++++++++++++++-----
 1 file changed, 34 insertions(+), 12 deletions(-)

diff --git a/gnu/packages/patches/webkitgtk-share-store.patch b/gnu/packages/patches/webkitgtk-share-store.patch
index 053d86fcf4..c02157076e 100644
--- a/gnu/packages/patches/webkitgtk-share-store.patch
+++ b/gnu/packages/patches/webkitgtk-share-store.patch
@@ -1,19 +1,41 @@
-Tell bubblewrap to share the store.  Required for programs that use the
+Tell bubblewrap to share the store, and _not_ to share traditional FHS
+directories that are not used in Guix.  Required for programs that use the
 sandboxing features such as Epiphany.
 
-See <https://bugs.gnu.org/40837>.
-Author: Jack Hill <jackhill@jackhill.us>
----
+See <https://bugs.gnu.org/40837> and <https://bugs.gnu.org/47628>.
+Authors: Jack Hill <jackhill@jackhill.us> and Mark H Weaver <mhw@netris.org>.
+
 diff --git a/Source/WebKit/UIProcess/Launcher/glib/BubblewrapLauncher.cpp b/Source/WebKit/UIProcess/Launcher/glib/BubblewrapLauncher.cpp
 --- a/Source/WebKit/UIProcess/Launcher/glib/BubblewrapLauncher.cpp
 +++ b/Source/WebKit/UIProcess/Launcher/glib/BubblewrapLauncher.cpp
-@@ -737,6 +737,9 @@ GRefPtr<GSubprocess> bubblewrapSpawn(GSubprocessLauncher* launcher, const Proces
-         "--ro-bind-try", "/usr/local/share", "/usr/local/share",
+@@ -749,26 +749,18 @@
+         "--ro-bind", "/sys/dev", "/sys/dev",
+         "--ro-bind", "/sys/devices", "/sys/devices",
+ 
+-        "--ro-bind-try", "/usr/share", "/usr/share",
+-        "--ro-bind-try", "/usr/local/share", "/usr/local/share",
          "--ro-bind-try", DATADIR, DATADIR,
  
-+       // Bind mount the store inside the WebKitGTK sandbox.
-+       "--ro-bind", "@storedir@", "@storedir@",
-+
-         // We only grant access to the libdirs webkit is built with and
-         // guess system libdirs. This will always have some edge cases.
-         "--ro-bind-try", "/lib", "/lib",
+-        // We only grant access to the libdirs webkit is built with and
+-        // guess system libdirs. This will always have some edge cases.
+-        "--ro-bind-try", "/lib", "/lib",
+-        "--ro-bind-try", "/usr/lib", "/usr/lib",
+-        "--ro-bind-try", "/usr/local/lib", "/usr/local/lib",
+-        "--ro-bind-try", LIBDIR, LIBDIR,
+-        "--ro-bind-try", "/lib64", "/lib64",
+-        "--ro-bind-try", "/usr/lib64", "/usr/lib64",
+-        "--ro-bind-try", "/usr/local/lib64", "/usr/local/lib64",
++        // Bind mount the store inside the WebKitGTK sandbox.
++        "--ro-bind", "@storedir@", "@storedir@",
+ 
++        // We only grant access to the libdirs webkit is built with.
++        "--ro-bind-try", LIBDIR, LIBDIR,
+         "--ro-bind-try", PKGLIBEXECDIR, PKGLIBEXECDIR,
+     };
+ 
+     if (launchOptions.processType == ProcessLauncher::ProcessType::DBusProxy) {
+         sandboxArgs.appendVector(Vector<CString>({
+-            "--ro-bind", "/usr/bin", "/usr/bin",
+             // This is a lot of access, but xdg-dbus-proxy is trusted so that's OK. It's sandboxed
+             // only because we have to mount .flatpak-info in its mount namespace. The user rundir
+             // is where we mount our proxy socket.
-- 
2.31.1