Universal 2nd Factor (U2F) Emulation C Library

Libu2f-emu, provides a C Library for the U2F device emulations.

API

The API is described in src/u2f-emu.h and src/u2f-emu-type.h.

It gives the possibility to create virtual emulated U2F devices with transport specific considerations. Four transports are available:

• USB
• NFC
• BLUETOOTH
• APDU

Once create, it is possible to interact with the devices by sending and receiving transport specific data through the API.

Device configuration

Each virtual device, for its configuration requires:

• an EC x509 certificate
• its EC private key
• 48 bits of entropy
• a global counter

All the files are grouped inside a setup_dir that can be created through the setup.sh script.

$ ./setup.sh <setup_dir>

Examples

For each transport, a code example is available and can be built:

$ make examples

USB:

Software that emulates U2F through a virtual USB device using UHID system API on Linux and the libu2f-emu.

$ ./examples/usb/u2f-emu-usb <setup_dir>

You can easily test the virtual device my registering it on websites or by playing with it on https://webauthn.io/.

Building

The project support two build systems:

• Autotools
• CMake
• Meson

Setup the build system:

# Autotools
$ ./autogen.sh
$ ./configure

# CMake
$ mkdir build && cd build
$ cmake ..

# Meson
$ meson build && cd build

Build and install the library:

$ make
$ make install

Doc

The doc is generated using doxygen:

$ make doc

The doc can be accessed here: doc/html/index.html.

Tests

Somes testsuites come with the project, these can be generated and run: gtest is required:

$ make check

Coverage

The coverage and its html report can be easily generated: gcov, gcovr and gtest are required.

# Autotools
$ ./configure --enable-coverage
$ make coverage

# CMake
$ cmake -DCMAKE_BUILD_TYPE=Coverage ..
$ make coverage

# Meson
$ meson -Dcoverage=true build && cd build
$ make test && make coverage

The coverage html report can be accessed here: coverage/index.html.

Pkg-config

After the installation, the pkg-config informations are set:

$ PKG_CONFIG_PATH=/usr/local/lib/pkgconfig pkgconf u2f-emu --libs --cflags

License

This project is licensed under GPL-2.0.

Author

César MattGorko Belley cesar.belley@lse.epita.fr