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Add LLVM KCFI support to the Rust compiler

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This commit adds LLVM Kernel Control Flow Integrity (KCFI) support to
the Rust compiler. It initially provides forward-edge control flow
protection for operating systems kernels for Rust-compiled code only by
aggregating function pointers in groups identified by their return and
parameter types. (See llvm/llvm-project@cff5bef.)

Forward-edge control flow protection for C or C++ and Rust -compiled
code "mixed binaries" (i.e., for when C or C++ and Rust -compiled code
share the same virtual address space) will be provided in later work as
part of this project by identifying C char and integer type uses at the
time types are encoded (see Type metadata in the design document in the
tracking issue #89653).

LLVM KCFI can be enabled with -Zsanitizer=kcfi.

Co-authored-by: bjorn3 <17426603+bjorn3@users.noreply.github.com>
This commit is contained in:
Ramon de C Valle 2022-11-21 21:29:00 -08:00
parent b7bc90fea3
commit 65698ae9f3
26 changed files with 231 additions and 28 deletions
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24
compiler/rustc_symbol_mangling/src/typeid.rs
View file

@ -3,6 +3,8 @@
use rustc_middle::ty::{FnSig, Ty, TyCtxt};
use rustc_target::abi::call::FnAbi;
use std::hash::Hasher;
use twox_hash::XxHash64;
mod typeid_itanium_cxx_abi;
use typeid_itanium_cxx_abi::TypeIdOptions;
@ -16,3 +18,25 @@ pub fn typeid_for_fnabi<'tcx>(tcx: TyCtxt<'tcx>, fn_abi: &FnAbi<'tcx, Ty<'tcx>>)
pub fn typeid_for_fnsig<'tcx>(tcx: TyCtxt<'tcx>, fn_sig: &FnSig<'tcx>) -> String {
typeid_itanium_cxx_abi::typeid_for_fnsig(tcx, fn_sig, TypeIdOptions::NO_OPTIONS)
}
/// Returns an LLVM KCFI type metadata identifier for the specified FnAbi.
pub fn kcfi_typeid_for_fnabi<'tcx>(tcx: TyCtxt<'tcx>, fn_abi: &FnAbi<'tcx, Ty<'tcx>>) -> u32 {
// An LLVM KCFI type metadata identifier is a 32-bit constant produced by taking the lower half
// of the xxHash64 of the type metadata identifier. (See llvm/llvm-project@cff5bef.)
let mut hash: XxHash64 = Default::default();
hash.write(
typeid_itanium_cxx_abi::typeid_for_fnabi(tcx, fn_abi, TypeIdOptions::NO_OPTIONS).as_bytes(),
);
hash.finish() as u32
}
/// Returns an LLVM KCFI type metadata identifier for the specified FnSig.
pub fn kcfi_typeid_for_fnsig<'tcx>(tcx: TyCtxt<'tcx>, fn_sig: &FnSig<'tcx>) -> u32 {
// An LLVM KCFI type metadata identifier is a 32-bit constant produced by taking the lower half
// of the xxHash64 of the type metadata identifier. (See llvm/llvm-project@cff5bef.)
let mut hash: XxHash64 = Default::default();
hash.write(
typeid_itanium_cxx_abi::typeid_for_fnsig(tcx, fn_sig, TypeIdOptions::NO_OPTIONS).as_bytes(),
);
hash.finish() as u32
}