RISC-V CFI specification

This document is capturing discussions at the SSLPCFI TG and attempts to document the baseline. This is not official specification and everything in this document may change. Control-flow Integrity (CFI) provides CPU instruction set architecture (ISA) capabilities to defend against Return-Oriented Programming (ROP) and Call/Jump-Oriented Programming (COP/JOP) style control-flow subversion attacks.

To enforce backward edge control flow integrity, the extension introduces a shadow stack. To enforce forward edge control flow integrity, the extension introduces labeled landing pad instructions.

License

This work is licensed under a Creative Commons Attribution 4.0 International License (CC-BY-4.0). See the LICENSE file for details.

Contributors

Contributors to this specification are contained in the contributors.adoc file.

For instructions on how to contribute please see the CONTRIBUTING file.

Dependencies

This project is built using AsciiDoctor (Ruby). The repository has been setup to build the PDF on checkin using GitHub actions. Workflow dependencies are located in the dependencies directory.

For more information on AsciiDoctor, specification guidelines, or building locally, see the RISC-V Documentation Developer Guide.

Cloning the project

This project uses GitHub Submodules to include the RISC-V docs-resources project to achieve a common look and feel.

When cloning this repository for the first time, you must either use git clone --recurse-submodules or execute git submodule init and git submodule update after the clone to populate the docs-resources directory. Failure to clone the submodule, will result in the PDF build fail with an error message like the following:

$ make
asciidoctor-pdf \
-a toc \
-a compress \
-a pdf-style=docs-resources/themes/riscv-pdf.yml \
-a pdf-fontsdir=docs-resources/fonts \
--failure-level=ERROR \
-o profiles.pdf profiles.adoc
asciidoctor: ERROR: could not locate or load the built-in pdf theme `docs-resources/themes/riscv-pdf.yml'; reverting to default theme
No such file or directory - notoserif-regular-subset.ttf not found in docs-resources/fonts
  Use --trace for backtrace
make: *** [Makefile:7: profiles.pdf] Error 1

Building the document

The final specification form of PDF can be generated using the make command.