lfi-bind

README

LFI Bind

This program makes it easy to do library sandboxing with LFI. It generates routines to initialize the library sandbox, and trampolines for calling functions from the library.

Installation

go build

Examples

See examples for some basic examples. See ./EXAMPLE.md for a step-by-step guide to recreating the add example manually.

Usage

The process for creating a sandboxed library is the following:

1. Compile your static library using the LFI compiler. This produces libfoo.a.
2. Create a "LFI library" by compiling libfoo.a to a static PIE and linking with boxrt (startup code that runs in the sandbox). Usually this command looks like $(LFICC) -Wl,--whole-archive libfoo.a -Wl,--no-whole-archive -Wl,--export-dynamic -lboxrt -static-pie -o libfoo.lfi.
3. Invoke lfi-bind, passing it libfoo.lfi and instructing it to generate an initialization file lib_init.c and trampoline file lib_trampolines.S.
4. Compile lib_init.c and lib_trampolines.S into your host application, allowing you to use the sandboxed library.

See the examples directory for real examples that you can try out.

Usage of ./lfi-bind:
  -gen-init string
    	output file for initialization functions
  -gen-trampolines string
    	output file for trampolines
  -lib string
    	library name for function prefixes (default "lib")
  -lib-path string
    	path to library executable at runtime
  -lib-prefix string
    	prefix to put on library symbols
  -symbols-prefix string
    	prefix used to match exported symbols
  -symbols string
    	comma-separated list of exported symbols
  -symbols-file string
    	list of symbols in a file, one line per symbol