| Message ID | 20160206004438.GA21780@www.outflux.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Feb 5, 2016 at 4:44 PM, Kees Cook <keescook@chromium.org> wrote: > The Android compilers enable some non-standard features by default. While > most Android build systems inject the needed "-mno-android" option via > KCFLAGS, it happens too late (at least on x86_64), since KBUILD_CFLAGS > gains KCFLAGS after running (and failing) many cc-option tests. (For > example, the stack-protector tests happen after arch-specific > KBUILD_CFLAGS are added but before the external KCFLAGS are added.) As > such, we should notice this option and immediately turn it on as the > first cc-option test we run. > > Signed-off-by: Kees Cook <keescook@chromium.org> Michal, is this okay? I'd like to get it into -next soon if possible. Thanks! -Kees > --- > Makefile | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/Makefile b/Makefile > index 6c1a3c247988..126c98b582bb 100644 > --- a/Makefile > +++ b/Makefile > @@ -393,6 +393,10 @@ KBUILD_CFLAGS := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \ > -Wno-format-security \ > -std=gnu89 > > +# We must turn off the Android-specific compiler options as early as possible > +# otherwise cc-option calls below may erroneously fail. > +KBUILD_CFLAGS += $(call cc-option,-mno-android,) > + > KBUILD_AFLAGS_KERNEL := > KBUILD_CFLAGS_KERNEL := > KBUILD_AFLAGS := -D__ASSEMBLY__ > -- > 2.6.3 > > > -- > Kees Cook > Chrome OS & Brillo Security
Dne 18.2.2016 v 00:03 Kees Cook napsal(a): > On Fri, Feb 5, 2016 at 4:44 PM, Kees Cook <keescook@chromium.org> wrote: >> The Android compilers enable some non-standard features by default. While >> most Android build systems inject the needed "-mno-android" option via >> KCFLAGS, it happens too late (at least on x86_64), since KBUILD_CFLAGS >> gains KCFLAGS after running (and failing) many cc-option tests. (For >> example, the stack-protector tests happen after arch-specific >> KBUILD_CFLAGS are added but before the external KCFLAGS are added.) As >> such, we should notice this option and immediately turn it on as the >> first cc-option test we run. >> >> Signed-off-by: Kees Cook <keescook@chromium.org> > > Michal, is this okay? I'd like to get it into -next soon if possible. Is there a way to detect these compilers and are there some canonical versions of these? I do not think it's a good idea to add workaround for each random gcc fork. Michal -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Feb 18, 2016 at 1:36 AM, Michal Marek <mmarek@suse.com> wrote: > Dne 18.2.2016 v 00:03 Kees Cook napsal(a): >> On Fri, Feb 5, 2016 at 4:44 PM, Kees Cook <keescook@chromium.org> wrote: >>> The Android compilers enable some non-standard features by default. While >>> most Android build systems inject the needed "-mno-android" option via >>> KCFLAGS, it happens too late (at least on x86_64), since KBUILD_CFLAGS >>> gains KCFLAGS after running (and failing) many cc-option tests. (For >>> example, the stack-protector tests happen after arch-specific >>> KBUILD_CFLAGS are added but before the external KCFLAGS are added.) As >>> such, we should notice this option and immediately turn it on as the >>> first cc-option test we run. >>> >>> Signed-off-by: Kees Cook <keescook@chromium.org> >> >> Michal, is this okay? I'd like to get it into -next soon if possible. > > Is there a way to detect these compilers and are there some canonical > versions of these? I do not think it's a good idea to add workaround for > each random gcc fork. It's detectable by -mno-android being a valid option. It's not a random gcc fork, as it's part of the Android SDK gcc prebuilts that all Android vendors and hobbiests use to build their kernels. -Kees
diff --git a/Makefile b/Makefile index 6c1a3c247988..126c98b582bb 100644 --- a/Makefile +++ b/Makefile @@ -393,6 +393,10 @@ KBUILD_CFLAGS := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \ -Wno-format-security \ -std=gnu89 +# We must turn off the Android-specific compiler options as early as possible +# otherwise cc-option calls below may erroneously fail. +KBUILD_CFLAGS += $(call cc-option,-mno-android,) + KBUILD_AFLAGS_KERNEL := KBUILD_CFLAGS_KERNEL := KBUILD_AFLAGS := -D__ASSEMBLY__
The Android compilers enable some non-standard features by default. While most Android build systems inject the needed "-mno-android" option via KCFLAGS, it happens too late (at least on x86_64), since KBUILD_CFLAGS gains KCFLAGS after running (and failing) many cc-option tests. (For example, the stack-protector tests happen after arch-specific KBUILD_CFLAGS are added but before the external KCFLAGS are added.) As such, we should notice this option and immediately turn it on as the first cc-option test we run. Signed-off-by: Kees Cook <keescook@chromium.org> --- Makefile | 4 ++++ 1 file changed, 4 insertions(+)