Messages in this thread | | | From | Nick Desaulniers <> | Date | Mon, 31 Jan 2022 11:04:36 -0800 | Subject | Re: [PATCH v4] fortify: Work around Clang inlining bugs |
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On Sun, Jan 30, 2022 at 10:22 AM Kees Cook <keescook@chromium.org> wrote: > > To enable FORTIFY_SOURCE support for Clang, the kernel must work around > a pair of bugs, related to Clang's inlining: > > 1) Change all the fortified string APIs into macros with different > inline names to bypass Clang's broken inline-of-a-builtin detection: > https://bugs.llvm.org/show_bug.cgi?id=50322 > > 2) Lift all misbehaving __builtin_object_size() calls into the macros > to bypass Clang's broken __builtin_object_size() arguments-of-an-inline > visibility: > https://github.com/ClangBuiltLinux/linux/issues/1401
^ mentions a difference in compilers for mode 1. I wonder if this patch could "hoist" the BOS calls into the macro ONLY for mode 1 and not mode 0 usage? i.e. the str* functions, not the mem* functions.
It's too late to fix these in clang-13. If we get a fix in clang-14 or later, what does that look like for this header? Is there a way we can provide a different header than include/linux/fortify-string.h just for clang-13 (or whatever versions until the above are fixed)?
I don't see this series getting backported to stable, where older versions of clang may still be in use.
I'm tempted to say "let's get get these 2 fixed in clang-14" but we'll probably have to trade something off the existing TODO list. -- Thanks, ~Nick Desaulniers
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