Messages in this thread | | | Date | Wed, 7 Sep 2022 16:18:40 -0700 | From | Kees Cook <> | Subject | Re: [PATCH v2 1/3] fortify: Fix __compiletime_strlen() under UBSAN_BOUNDS_LOCAL |
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On Tue, Sep 06, 2022 at 07:36:46PM -0700, Nick Desaulniers wrote: > On Fri, Sep 2, 2022 at 1:43 PM Kees Cook <keescook@chromium.org> wrote: > > > > Co-developed-by: Nick Desaulniers <ndesaulniers@google.com> > > That's overly generous of you!
Well, it was a lot of work to track down, and you wrote it up that way, I just moved things around a little bit. :)
> Anyways, the disassembly LGTM and the bot also came back green. > > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > Tested-by: Android Treehugger Robot > Link: https://android-review.googlesource.com/c/kernel/common/+/2206839
Thank you!
> Another thought, Nikita suggested that you could also compare mode 1 vs mode 3: > https://github.com/llvm/llvm-project/issues/57510#issuecomment-1235126343
Yeah, it could work (I tried this as well), but I think the better approach is checking index 0.
> That said, since mode 3 returns 0 for "unknown" I'd imagine that > wouldn't be pretty since it wouldn't be a direct comparison against > __p_size.
Yeah -- it is a little weird. I might come back to this if we get more glitches like this in the future.
-- Kees Cook
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