Messages in this thread | | | Date | Mon, 3 Oct 2022 13:57:53 -0700 | From | Kees Cook <> | Subject | Re: [PATCH] hardening: Remove Clang's enable flag for -ftrivial-auto-var-init=zero |
| |
On Mon, Oct 03, 2022 at 09:41:19AM -0700, Nathan Chancellor wrote: > On Thu, Sep 29, 2022 at 11:06:24PM -0700, Kees Cook wrote: > > Now that Clang's -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang > > option is no longer required, remove it from the command line. Clang 16 > > and later will warn when it is used, which will cause Kconfig to think > > it can't use -ftrivial-auto-var-init=zero at all. Check for whether it > > is required and only use it when so. > > > > Cc: Nathan Chancellor <nathan@kernel.org> > > Cc: Masahiro Yamada <masahiroy@kernel.org> > > Cc: Nick Desaulniers <ndesaulniers@google.com> > > Cc: linux-kbuild@vger.kernel.org > > Cc: llvm@lists.linux.dev > > Cc: stable@vger.kernel.org > > Fixes: f02003c860d9 ("hardening: Avoid harmless Clang option under CONFIG_INIT_STACK_ALL_ZERO") > > Signed-off-by: Kees Cook <keescook@chromium.org> > > Thanks for sending this change! > > Reviewed-by: Nathan Chancellor <nathan@kernel.org> > Tested-by: Nathan Chancellor <nathan@kernel.org>
Thanks!
> > Please consider getting this to Linus ASAP so that this can start > filtering into stable now that the LLVM change has landed, as I lost the > ability to use CONFIG_INIT_STACK_ALL_ZERO after upgrading my toolchain > over the weekend :)
Yup -- it's in my PR for the hardening tree sent on Saturday.
> Additionally, I am not sure the fixes tag is going to ensure that this > change automatically makes it back to 5.15 and 5.10, which have > commit f0fe00d4972a ("security: allow using Clang's zero initialization > for stack variables") but not commit f02003c860d9 ("hardening: Avoid > harmless Clang option under CONFIG_INIT_STACK_ALL_ZERO"). I guess if I > am reading the stable documentation right, we could do something like: > > Cc: stable@vger.kernel.org # dcb7c0b9461c + f02003c860d9 > Fixes: f0fe00d4972a ("security: allow using Clang's zero initialization for stack variables") > > but I am not sure. I guess we can always just send manual backports > once it is merged.
Ah, good point. Yeah, probably just do backports of f02003c860d9 and this one.
-- Kees Cook
| |