On Tue, Jul 30, 2024 at 1:38 PM Miguel Ojeda <miguel.ojeda.sandonis@xxxxxxxxx> wrote: > > On Tue, Jul 30, 2024 at 11:40 AM Alice Ryhl <aliceryhl@xxxxxxxxxx> wrote: > > > > Introduce a Kconfig option for enabling the experimental option to > > normalize integer types. This ensures that integer types of the same > > size and signedness are considered compatible by the Control Flow > > Integrity sanitizer. > > > > This option exists for compatibility with Rust, as C and Rust do not > > have the same set of integer types. There are cases where C has two > > different integer types of the same size and alignment, but Rust only > > has one integer type of that size and alignment. When Rust calls into > > C functions using such types in their signature, this results in CFI > > failures. > > > > This patch introduces a dedicated option for this because it is > > undesirable to have CONFIG_RUST affect CC_FLAGS in this way. > > Is there any case where we would want CFI_ICALL_NORMALIZE_INTEGERS > when Rust is not enabled, then? If not, is the idea here to make this > an explicit extra question in the config before enabling Rust? Or why > wouldn't it be done automatically? I'm adding this flag to make the bringup process for RUST easier. I'm working on enabling RUST in a new branch. We're eventually going to have both RUST and CFI_ICALL_NORMALIZE_INTEGERS enabled in our build, but the path to getting there is complex and we would like to turn on CFI_ICALL_NORMALIZE_INTEGERS first, and then turn on RUST later. Both options are non-trivial to turn on and I want to disentangle them. Alice
