Wire up CONFIG_KSTACK_ERASE to Clang 21's new stack depth tracking callback[1] option.
Link: https://clang.llvm.org/docs/SanitizerCoverage.html#tracing-stack-depth [1] Signed-off-by: Kees Cook kees@kernel.org --- Cc: Arnd Bergmann arnd@arndb.de Cc: Masahiro Yamada masahiroy@kernel.org Cc: Nathan Chancellor nathan@kernel.org Cc: Nicolas Schier nicolas.schier@linux.dev Cc: Marco Elver elver@google.com Cc: Andrey Konovalov andreyknvl@gmail.com Cc: Andrey Ryabinin ryabinin.a.a@gmail.com Cc: Ard Biesheuvel ardb@kernel.org Cc: "Gustavo A. R. Silva" gustavoars@kernel.org Cc: linux-kbuild@vger.kernel.org Cc: kasan-dev@googlegroups.com Cc: linux-hardening@vger.kernel.org --- security/Kconfig.hardening | 5 ++++- scripts/Makefile.kstack_erase | 6 ++++++ 2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index f7aa2024ab25..b9a5bc3430aa 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -82,10 +82,13 @@ choice
endchoice
+config CC_HAS_SANCOV_STACK_DEPTH_CALLBACK + def_bool $(cc-option,-fsanitize-coverage-stack-depth-callback-min=1) + config KSTACK_ERASE bool "Poison kernel stack before returning from syscalls" depends on HAVE_ARCH_KSTACK_ERASE - depends on GCC_PLUGINS + depends on GCC_PLUGINS || CC_HAS_SANCOV_STACK_DEPTH_CALLBACK help This option makes the kernel erase the kernel stack before returning from system calls. This has the effect of leaving diff --git a/scripts/Makefile.kstack_erase b/scripts/Makefile.kstack_erase index 5223d3a35817..c7bc2379e113 100644 --- a/scripts/Makefile.kstack_erase +++ b/scripts/Makefile.kstack_erase @@ -8,6 +8,12 @@ kstack-erase-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK_VERBOSE) += -fplugin-arg-stack DISABLE_KSTACK_ERASE := -fplugin-arg-stackleak_plugin-disable endif
+ifdef CONFIG_CC_IS_CLANG +kstack-erase-cflags-y += -fsanitize-coverage=stack-depth +kstack-erase-cflags-y += -fsanitize-coverage-stack-depth-callback-min=$(CONFIG_KSTACK_ERASE_TRACK_MIN_SIZE) +DISABLE_KSTACK_ERASE := -fno-sanitize-coverage=stack-depth +endif + KSTACK_ERASE_CFLAGS := $(kstack-erase-cflags-y)
export STACKLEAK_CFLAGS DISABLE_KSTACK_ERASE