diff --git a/doc/manual/src/language/derivations.md b/doc/manual/src/language/derivations.md index 8e3f0f791..b57f6bb6a 100644 --- a/doc/manual/src/language/derivations.md +++ b/doc/manual/src/language/derivations.md @@ -264,7 +264,8 @@ The [`builder`](#attr-builder) is executed as follows: - `PATH` is set to `/path-not-set` to prevent shells from initialising it to their built-in default value. - - `HOME` is set to `/homeless-shelter` to prevent programs from + - `HOME` is set to `/proc/homeless-shelter` on Linux and `/homeless-shelter` + on OSX, to prevent programs from using `/etc/passwd` or the like to find the user's home directory, which could cause impurity. Usually, when `HOME` is set, it is used as the location of the home directory, even if diff --git a/src/libstore/unix/build/local-derivation-goal.cc b/src/libstore/unix/build/local-derivation-goal.cc index d3482df17..e1035fbdd 100644 --- a/src/libstore/unix/build/local-derivation-goal.cc +++ b/src/libstore/unix/build/local-derivation-goal.cc @@ -102,7 +102,14 @@ void handleDiffHook( } } +// We want $HOME to be un-creatable in the sandbox. On Linux, +// you can't create anything inside /proc since it's a virtual filesystem. +// On Darwin it seems that `/homeless-shelter` is good enough. +#if __linux__ +const Path LocalDerivationGoal::homeDir = "/proc/homeless-shelter"; +#else const Path LocalDerivationGoal::homeDir = "/homeless-shelter"; +#endif LocalDerivationGoal::~LocalDerivationGoal()