Restore parent mount namespace before executing a child process

This ensures that they can't write to /nix/store. Fixes #2535.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index bda87bee4..2689cbd8b 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -514,4 +514,13 @@ typedef std::function<bool(const Path & path)> PathFilter;
 extern PathFilter defaultPathFilter;
 
 
+/* Save the current mount namespace. Ignored if called more than
+   once. */
+void saveMountNamespace();
+
+/* Restore the mount namespace saved by saveMountNamespace(). Ignored
+   if saveMountNamespace() was never called. */
+void restoreMountNamespace();
+
+
 }