capsh

The capability-aware shell starts applications from inside Capsicum's capability mode. This allows for untrusted applications to be sandboxed from inception.

Note: currently, this software only works on a version of FreeBSD that supports direct execution of ld-elf.so.1 with an explicit file descriptor argument, i.e., 12-CURRENT post-r318431.

Build it:

1. Download, build and install libpreopen
2. Build capsh with CMake and (optionally) Ninja:

   $ git clone https://github.com/musec/capsh
   $ cd capsh
   $ mkdir build
   $ cd build
   $ cmake -G Ninja ..    # or leave out Ninja to generate Makefiles
   $ ninja                # or make, or gmake

Use it:

Currently, capsh can only do one thing: execute a single binary, specified by absolute path, from within a Capsicum sandbox. Also, the binaries it can execute aren't very interesting (we aren't really leveraging much of libpreopen yet), so you may have to content yourself with:

$ ./src/capsh /bin/echo "hi"
hi