Ledger Nano S SDK for Rust Applications

Crate that allows developing Ledger Nano S apps in Rust with a default configuration.

Contains:

• low-level pre-generated bindings to the C SDK version 2.0
• some safe wrappers over common syscalls
• IO abstractions

This SDK is still in BETA as wrappers are currently missing, but two apps were made using it:

• A demo application with a signature UI workflow
• A Password Manager

All issues and PRs are welcome !

Usage

Building requires adding a toolchain to your Rust installation, and both Clang and arm-none-eabi-gcc. On Ubuntu, gcc-multilib might also be required.

Using rustc nightly builds is recommanded as some unstable features are required.

• rustup default nightly
• rustup target add thumbv6m-none-eabi
• install Clang.
• install an ARM GCC toolchain

Generating bindings for the C sdk

The Rust SDK uses FFIs to call functions defined in the C SDK. The C function signatures and types are automatically "translated" to Rust by using bindgen, which generates the appropriate bindings.

The bindings are split into two different files:

• The bindings.rs which contains all the os, io, and seproxyhal bindings.
• The usbbindings.rs which contains basically all the bindings needed to interact with lib_stusb.

Two corresponding header files exist in binding_headers directory: bindings.h and usbbindings.h which are provided in order for you to be able to re-generate those bindings easily. They contain all the #defines and #includes necessary to generate the appropriate bindings.

Here are the steps to follow in order to generate those bindings by yourself:

1. Make sure you have bindgen setup
2. Run this command to generate the bindings.rs file (you might need to adapt -I/usr/arm-linux/gnueabihf/include to your configuration):

bindgen ./binding_headers/bindings.h --use-core --no-prepend-enum-name --no-doc-comments --no-derive-debug --ctypes-prefix=cty --no-layout-tests --with-derive-default -- --target=thumbv7m-none-eabi -fshort-enums -I/usr/arm-linux-gnueabihf/include -Inanos-secure-sdk/include -Inanos-secure-sdk/lib_cxng/include > ./src/bindings.rs

3. Run this command to generate the usbbindings.rs file (you might need to adapt -I/usr/arm-linux-gnueabihf/include to your configuration):

bindgen ./binding_headers/usbbindings.h --use-core --no-prepend-enum-name --no-doc-comments --no-derive-debug --ctypes-prefix=cty --no-layout-tests --with-derive-default -- --target=thumbv7m-none-eabi -fshort-enums -Inanos-secure-sdk/lib_stusb/STM32_USB_Device_Library/Core/Inc -I/usr/arm-linux-gnueabihf/include -Inanos-secure-sdk/lib_stusb > ./src/usbbindings.rs

4. Modify the generated .rs files and add those lines at the BEGINNING of both files:

#![allow(non_snake_case)]
#![allow(non_upper_case_globals)]
#![allow(non_camel_case_types)]
#![allow(clippy::upper_case_acronyms)]
#![allow(clippy::too_many_arguments)]

5. Remove the line containing IO_USB_MAX_ENDPOINTS in the bindings.rs file.
6. Profit!

Note that for step 4, you might need to change /usr/arm-linux/gnueabihf/include to another directory that includes the stdio.h header for the arm target.

Building with rustc < 1.54

Building before rustc 1.54 should fail with error[E0635]: unknown feature const_fn_trait_bound.

This is solved by activating a specific feature: cargo build --features pre1_54

Contributing

Make sure you've followed the installation steps above. In order for your PR to be accepted, it will have to pass the CI, which performs the following checks:

• Check if the code builds on nightly
• Check that clippy does not emit any warnings
• check that your code follows rustfmt's format (using cargo fmt)