Debugging

Debugging

Debugging GEF has a trick, let's see some examples

Debugging with pdb

Open gef.py

Search for class NopCommand(GenericCommand), go to do_invoke method and insert:

import pdb; pdb.set_trace()

Open a gdb session -> start -> nop

Done!

gef➤  nop
> /home/dreg/.gef-7c170cf6be3d84b2672a22e43b9128a23fe53c3b.py(6075)do_invoke()
-> args : argparse.Namespace = kwargs["arguments"]
(Pdb) ll
6070        @only_if_gdb_running
6071        @parse_arguments({"address": "$pc"}, {"--i": 1, "--b": True, "--f": True, "--n": True})
6072        def do_invoke(self, _: List[str], **kwargs: Any) -> None:
6073            import pdb; pdb.set_trace()
6074
6075 ->         args : argparse.Namespace = kwargs["arguments"]
6076            address = parse_address(args.address)

Learn more about pdb

Debugging with PyCharm

Install pycharm

Create a new project:

Go to menu -> Run -> Edit configurations...:

Create a Python Debug Server:

Debug your new Unnamed:

Copy the info from output Window to gef.py:

First, add to gef.py:

import pydevd_pycharm

Second, search for class NopCommand(GenericCommand), go to do_invoke method and insert:

pydevd_pycharm.settrace('localhost', port=35747, stdoutToServer=True, stderrToServer=True)

Open a gdb session -> start -> nop

Done!

Debugging with VSCode

The approach to debug GEF with VSCode is relatively similar to that of PyCharm. Make sure to install the Python extension for VSCode. This will install debugpy, a remote debugger that you can connect to from VSCode and debug anything in GEF from your session (breakpoints, watchpoints, etc.). Debugging a Python app from VSCode is extensively covered in the official docs to refer to them if you're not sure how it works.

To start a debugging session in GEF, manually run the following Python commands

gef> pi import debugpy; debugpy.listen(5678); pi debugpy.wait_for_client()

Alternatively a convenience script named vscode_debug.py can also be found in the scripts folder, which you can invoke easily simply using the GDB source command:

gef> source /path/to/gef/scripts/vscode_debug.py

GEF will be suspended, waiting for a client to connect to the debugger to resume the execution. Then from your VSCode, edit or create /path/to/gef/.vscode/launch.json, and add a debug configuration to attach to GEF, by specifying the IP address and port (on localhost in the example below, but the remote server can be anywhere):

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Python: Attach to GEF",
            "type": "python",
            "request": "attach",
            "connect": {
                "host": "localhost",
                "port": 5678
            }
        }
    ]
}

Everything is ready to attach to GEF. By default, you can simply hit F5 on VSCode (Start Debugging)