Messages in this thread |  | | From | Marco Elver <> | Date | Thu, 21 Oct 2021 08:00:00 +0200 | Subject | Re: [PATCH] compiler-gcc.h: Define __SANITIZE_ADDRESS__ under hwaddress sanitizer |
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On Wed, 20 Oct 2021 at 22:00, Kees Cook <keescook@chromium.org> wrote: > When Clang is using the hwaddress sanitizer, it sets __SANITIZE_ADDRESS__ > explicitly: > > #if __has_feature(address_sanitizer) || __has_feature(hwaddress_sanitizer) > /* Emulate GCC's __SANITIZE_ADDRESS__ flag */ > #define __SANITIZE_ADDRESS__ > #endif
Hmm, the comment is a little inaccurate if hwaddress sanitizer is on, but I certainly wouldn't want compiler-clang.h to start emulating gcc here and start defining __SANITIZE_HWADDRESS__ if the places where we check it are the same as __SANITIZE_ADDRESS__. So this patch is the right approach.
> Once hwaddress sanitizer was added to GCC, however, a separate define > was created, __SANITIZE_HWADDRESS__. The kernel is expecting to find > __SANITIZE_ADDRESS__ in either case, though, and the existing string > macros break on supported architectures: > > #if (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) && \ > !defined(__SANITIZE_ADDRESS__) > > where as other architectures (like arm32) have no idea about hwaddress > sanitizer and just check for __SANITIZE_ADDRESS__: > > #if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)
arm32 doesn't support KASAN_SW_TAGS, so I think the bit about arm32 is irrelevant.
Only arm64 can, and the reason that arm64 doesn't check against "defined(CONFIG_KASAN)" is because we also have KASAN_HW_TAGS (no compiler instrumentation).
> This would lead to compiler foritfy self-test warnings when building > with CONFIG_KASAN_SW_TAGS=y: > > warning: unsafe memmove() usage lacked '__read_overflow2' symbol in lib/test_fortify/read_overflow2-memmove.c > warning: unsafe memcpy() usage lacked '__write_overflow' symbol in lib/test_fortify/write_overflow-memcpy.c > ... > > Sort this out by also defining __SANITIZE_ADDRESS__ in GCC under the > hwaddress sanitizer. > > Suggested-by: Arnd Bergmann <arnd@arndb.de> > Cc: Nathan Chancellor <nathan@kernel.org> > Cc: Nick Desaulniers <ndesaulniers@google.com> > Cc: Miguel Ojeda <ojeda@kernel.org> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Marco Elver <elver@google.com> > Cc: Will Deacon <will@kernel.org> > Cc: Arvind Sankar <nivedita@alum.mit.edu> > Cc: Masahiro Yamada <masahiroy@kernel.org> > Cc: llvm@lists.linux.dev > Signed-off-by: Kees Cook <keescook@chromium.org>
Other than that,
Reviewed-by: Marco Elver <elver@google.com>
Thanks!
> --- > I'm intending to take this via my overflow series, since that is what introduces > the compile-test regression tests (which found this legitimate bug). :) > > -Kees > --- > include/linux/compiler-gcc.h | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h > index 6f24eb8c5dda..ccbbd31b3aae 100644 > --- a/include/linux/compiler-gcc.h > +++ b/include/linux/compiler-gcc.h > @@ -121,6 +121,14 @@ > #define __no_sanitize_coverage > #endif > > +/* > + * Treat __SANITIZE_HWADDRESS__ the same as __SANITIZE_ADDRESS__ in the kernel, > + * matching the defines used by Clang. > + */ > +#ifdef __SANITIZE_HWADDRESS__ > +#define __SANITIZE_ADDRESS__ > +#endif > + > /* > * Turn individual warnings and errors on and off locally, depending > * on version. > -- > 2.30.2 >
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