system/linux
system/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux synced 2024-10-06 19:34:19 +00:00
Code Issues Packages Projects Releases Wiki Activity

hardening: Remove Clang's enable flag for -ftrivial-auto-var-init=zero

Browse source 
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: f02003c860 ("hardening: Avoid harmless Clang option under CONFIG_INIT_STACK_ALL_ZERO")
Signed-off-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Kees Cook 2022-09-29 22:57:43 -07:00
parent 17006e86a7
commit 607e57c6c6
2 changed files with 12 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
Makefile
View file

@ -831,8 +831,8 @@ endif
# Initialize all stack variables with a zero value. # Initialize all stack variables with a zero value.
ifdef CONFIG_INIT_STACK_ALL_ZERO ifdef CONFIG_INIT_STACK_ALL_ZERO
KBUILD_CFLAGS += -ftrivial-auto-var-init=zero KBUILD_CFLAGS += -ftrivial-auto-var-init=zero
ifdef CONFIG_CC_IS_CLANG ifdef CONFIG_CC_HAS_AUTO_VAR_INIT_ZERO_ENABLER
# https://bugs.llvm.org/show_bug.cgi?id=45497 # https://github.com/llvm/llvm-project/issues/44842
KBUILD_CFLAGS += -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang KBUILD_CFLAGS += -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang
endif endif
endif endif

14
security/Kconfig.hardening
View file

@ -22,11 +22,17 @@ menu "Memory initialization"
config CC_HAS_AUTO_VAR_INIT_PATTERN config CC_HAS_AUTO_VAR_INIT_PATTERN
def_bool $(cc-option,-ftrivial-auto-var-init=pattern) def_bool $(cc-option,-ftrivial-auto-var-init=pattern)
config CC_HAS_AUTO_VAR_INIT_ZERO config CC_HAS_AUTO_VAR_INIT_ZERO_BARE
# GCC ignores the -enable flag, so we can test for the feature with def_bool $(cc-option,-ftrivial-auto-var-init=zero)
# a single invocation using the flag, but drop it as appropriate in
# the Makefile, depending on the presence of Clang. config CC_HAS_AUTO_VAR_INIT_ZERO_ENABLER
# Clang 16 and later warn about using the -enable flag, but it
# is required before then.
def_bool $(cc-option,-ftrivial-auto-var-init=zero -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang) def_bool $(cc-option,-ftrivial-auto-var-init=zero -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang)
depends on !CC_HAS_AUTO_VAR_INIT_ZERO_BARE
config CC_HAS_AUTO_VAR_INIT_ZERO
def_bool CC_HAS_AUTO_VAR_INIT_ZERO_BARE || CC_HAS_AUTO_VAR_INIT_ZERO_ENABLER
choice choice
prompt "Initialize kernel stack variables at function entry" prompt "Initialize kernel stack variables at function entry"