Messages in this thread | | | From | Nick Desaulniers <> | Date | Mon, 31 Jan 2022 11:09:27 -0800 | Subject | Re: [PATCH] fortify: Update compile-time tests for Clang 14 |
| |
On Sun, Jan 30, 2022 at 10:16 AM Kees Cook <keescook@chromium.org> wrote: > > Clang 14 introduces support for compiletime_assert(). Update the > compile-time warning regex to catch Clang's variant of the warning text > in preparation for Clang supporting CONFIG_FORTIFY_SOURCE.
https://twitter.com/ifosteve/status/1190348262500421634?lang=en error messages can change over time. More thoughts below.
> > Cc: Nathan Chancellor <nathan@kernel.org> > Cc: Nick Desaulniers <ndesaulniers@google.com> > Cc: linux-hardening@vger.kernel.org > Cc: llvm@lists.linux.dev > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > I'm splitting this patch out of the main Clang FORTIFY enabling patch. > --- > scripts/test_fortify.sh | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/scripts/test_fortify.sh b/scripts/test_fortify.sh > index a4da365508f0..c2688ab8281d 100644 > --- a/scripts/test_fortify.sh > +++ b/scripts/test_fortify.sh > @@ -46,8 +46,12 @@ if "$@" -Werror -c "$IN" -o "$OUT".o 2> "$TMP" ; then > status="warning: unsafe ${FUNC}() usage lacked '$WANT' symbol in $IN" > fi > else > - # If the build failed, check for the warning in the stderr (gcc). > - if ! grep -q -m1 "error: call to .\b${WANT}\b." "$TMP" ; then > + # If the build failed, check for the warning in the stderr. > + # GCC: > + # ./include/linux/fortify-string.h:316:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning] > + # Clang 14: > + # ./include/linux/fortify-string.h:316:4: error: call to __write_overflow_field declared with 'warning' attribute: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror,-Wattribute-warning] > + if ! grep -Eq -m1 "error: call to .?\b${WANT}\b.?" "$TMP" ; then
Doesn't this depend on -Werror being set? I guess it did so before hand, too, but couldn't I unset CONFIG_WERROR then this check would still fail (since instead of `error:` we'd have `warning:`)? If we used __attribute__((error(""))) then this would always be an error. Right now, it is only because -Werror is set promoting the warning diagnostic to an error.
> status="warning: unsafe ${FUNC}() usage lacked '$WANT' warning in $IN" > fi > fi > -- > 2.30.2 >
-- Thanks, ~Nick Desaulniers
| |