Signelf is a toolset written in C++ for signing elf binaries, specifically linux shared object, though in theory, any elf binary may be signed. It uses openssl's libcrypt to RSA sign the library, and the same to validate the signature.
I suppose you're curious why someone would want to sign an elf binary? Suppose you have an application that uses plugins. If each of those plugins were signed, you could be assured that each was coming from a trudsted source, unmodified, and uncorrupted. For secure systems this can be very important. Signelf uses RSA signing through openssl's libcrypt library. RSA key pairs are generated, along with a signing tool, and static library to link into your application. You can validate shared objects before dynamically loading them with a simple function call. To sign a shared object (or any elf binary) you simply run the signing app. It will take the data and text sections of the binary, and sign them with the keypair that was created, then append that signature to the shared object as another elf section.
make
make install
from a prompt, run: signelf <path/to/shared/object.so>
link in libsignelf.a
call this:
#include "signelf.h"
#include "pubkey.h"
bRetval = signelf::verifyLib(szKeyBuf, sizeof(szKeyBuf), "/path/to/shared/object.so");
szKeyBuf is the public key, and it is defined in pubkey.h.
LGPL-2.1-or-later
Original author: Joe Fox joe@codenoise.com
Original repository: https://sourceforge.net/projects/signelf/
The repo showed this additional text:
Acknowledgements
Big thanks to Doug Keith and Pete Birch. Huge thanks to the openssl guys for
making libcrypt, and providing a solid interface for strong encryption! Also a
big thanks for Linspire, Inc for sponsoring this development.
Drop me a line at: joe@codenoise.com if you find this useful!
Thanks
-Joe