Initial back-edge CFI implementation#3606
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cfallin merged 1 commit intobytecodealliance:mainfrom Aug 3, 2022
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Subscribe to Label Actioncc @peterhuene DetailsThis issue or pull request has been labeled: "cranelift", "cranelift:area:aarch64", "cranelift:area:machinst", "cranelift:area:x64", "cranelift:meta", "wasmtime:api"Thus the following users have been cc'd because of the following labels:
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Thanks, this looks great overall!
Some nits related to flags-passing, a question on macOS, and some other misc things, but nothing too major.
Give the user the option to sign and to authenticate function return addresses with the operations introduced by the Pointer Authentication extension to the Arm instruction set architecture. Copyright (c) 2021, Arm Limited.
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This looks good now; thanks for the patience on the iteration! I'll go ahead and merge; we can work out whether to enable it by default on macOS/aarch64 (comment below) as a followup.
This was referenced Aug 4, 2022
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This pull request is meant to illustrate the RFC proposal to improve control flow integrity for compiled WebAssembly code by using the Pointer Authentication extension to the Arm instruction set architecture (bytecodealliance/rfcs#17), so it is not in a shape to be merged yet. The generation of the unwinding information is a hack to make things work (i.e. pass the tests) before there is a resolution to gimli-rs/gimli#130 and gimli-rs/gimli#608.
P.S. Actually I apply another hack to test the code - I change the processor feature detection logic in
cranelift/native/src/lib.rs, so that the availability of PAuth is hardcoded (and there is no need to use a nightly toolchain). What you see here and what CI is testing is the clean code, though.P.P.S. The RFC proposal has now been merged, and the changes in this PR have been updated the reflect the final version of the proposal, so they are now ready. No hacks are necessary (and have been removed from the code), but on Linux unwinding through functions with signed return addresses will result in crashes unless the unwinder includes the fix discussed in issue #3183 (note that return address signing is not enabled by default).