Reapply "Disable gVisor's DirectFS feature.""

This reverts commit 68f8338d20.

Fixes #982

CHANGELOG.md

@@ -7,6 +7,11 @@ since 0.4.1, and this project adheres to [Semantic Versioning](https://semver.or
 
 ## [Unreleased](https://github.com/freedomofpress/dangerzone/compare/v0.8.0...HEAD)
 
+### Added
+
+- Disable gVisor's DirectFS feature ([#226](https://github.com/freedomofpress/dangerzone/issues/226)).
+  Thanks [EtiennePerot](https://github.com/EtiennePerot) for the contribution.
+
 ## [0.8.0](https://github.com/freedomofpress/dangerzone/compare/v0.8.0...0.7.1)
 
 ### Added

dangerzone/gvisor_wrapper/entrypoint.py

@@ -142,6 +142,9 @@ runsc_argv = [
     "--rootless=true",
     "--network=none",
     "--root=/home/dangerzone/.containers",
+    # Disable DirectFS for to make the seccomp filter even stricter,
+    # at some performance cost.
+    "--directfs=false",
 ]
 if os.environ.get("RUNSC_DEBUG"):
     runsc_argv += ["--debug=true", "--alsologtostderr=true"]