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Installing GEF

Prerequisites

GDB

Only GDB 8 and higher is required. It must be compiled with Python 3.6 or higher support. For most people, simply using your distribution package manager should be enough.

As of January 2020, GEF officially doesn't support Python 2 any longer, due to Python 2 becoming officially deprecated.

GEF will then only work for Python 3. If you absolutely require GDB + Python 2, please use GEF-Legacy instead. Note that gef-legacy won't provide new features, and only functional bugs will be handled.

You can verify it with the following command:

$ gdb -nx -ex 'pi print(sys.version)' -ex quit

This should display your version of Python compiled with gdb.

$ gdb -nx -ex 'pi print(sys.version)' -ex quit
3.6.9 (default, Nov  7 2019, 10:44:02)
[GCC 8.3.0]

Python dependencies

There are none: GEF works out of the box!

GEF itself provides most (if not all 🤯) features required for typical sessions. However, GEF can be easily extended via - community-built scripts, functions and architectures in the repo gef-extras (see below) - your own script which can leverage the GEF API for the heavy lifting

Standalone

Quick install

The quickest way to get started with GEF is through the installation script available. Simply make sure you have GDB 8.0 or higher, compiled with Python 3.6 or higher, and run

bash -c "$(curl -fsSL https://gef.blah.cat/sh)"

Or if you prefer wget

bash -c "$(wget https://gef.blah.cat/sh -O -)"

Alternatively from inside gdb directly:

$ gdb -q
(gdb) pi import urllib.request as u, tempfile as t; g=t.NamedTemporaryFile(suffix='-gef.py'); open(g.name, 'wb+').write(u.urlopen('https://tinyurl.com/gef-master').read()); gdb.execute('source %s' % g.name)

That's it! GEF is installed and correctly set up. You can confirm it by checking the ~/.gdbinit file and see a line that sources (i.e. loads) GEF.

$ cat ~/.gdbinit
source ~/.gdbinit-gef.py

Update

If your host/VM is connected to the Internet, you can update gef easily to the latest version (even without git installed). with python /path/to/gef.py --update

$ python ~/.gdbinit-gef.py --update
Updated

This will deploy the latest version of gef's main branch from Github. If no updates are available, gef will respond No update instead.

Using git

To contribute to GEF, you might prefer using git directly.

$ git clone https://github.com/hugsy/gef.git
$ echo source `pwd`/gef/gef.py >> ~/.gdbinit

GEF is in very active development, so the default branch is dev. This is the branch you must use if you intend to submit pull requests.

However if you prefer a more stable life, you can then switch to the main branch:

$ git checkout main

The main branch gets only updated for new releases, or also when critical fixes occur and need to be patched urgently.

Community repository: GEF-Extras

GEF was built to also provide a solid base for external scripts. The repository gef-extras is an open repository where anyone can freely submit their own commands to extend GDB via GEF's API.

To benefit from it:

# using the automated way
## via the install script
$ bash -c "$(wget https://github.com/hugsy/gef/raw/main/scripts/gef-extras.sh -O -)"

# or manually
## clone the repo
$ git clone https://github.com/hugsy/gef-extras.git

## then specify gef to load this directory
$ gdb -ex 'gef config gef.extra_plugins_dir "/path/to/gef-extras/scripts"' -ex 'gef save' -ex quit
[+] Configuration saved

You can also use the structures defined from this repository:

$ gdb -ex 'gef config pcustom.struct_path "/path/to/gef-extras/structs"' -ex 'gef save' -ex quit
[+] Configuration saved

There, you're now fully equipped epic pwnage with all GEF's goodness!!

Uninstalling GEF

Prevent script loading

GDB provides the -nx command line flag to disable the commands from the ~/.gdbinit to be executed.

gdb -nx

Disable GEF

To disable GEF without removing it, go to editing ~/.gdbinit, spot the line that sources GEF, and comment / delete that line:

So:

$ cat ~/.gdbinit
source /my/path/to/gef.py

Will become:

$ cat ~/.gdbinit
# source /my/path/to/gef.py

Restart GDB, GEF is gone. Note that you can also load GEF at any moment during your GDB session as such:

$ gdb
(gdb) source /my/path/to/gef.py

Remove GEF

GEF is a one-file GDB script. Therefore, to remove GEF simply spot the location it was installed (for example, by using ~/.gdbinit) and delete the file. If a configuration file was created, it will be located as ~/.gef.rc and can also be deleted:

$ cat ~/.gdbinit
# source /my/path/to/gef.py
$ rm /my/path/to/gef.py ~/.gef.rc

GEF is totally removed from your system.