diff options
| author | Kees Cook <keescook@chromium.org> | 2022-05-03 13:55:03 -0700 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2022-05-08 01:33:07 -0700 |
| commit | 035f7f87b7295a342577aebd7b5b451f1e2a353c (patch) | |
| tree | e7c51ad07b1fa5f4c2f870c2045b8d27c5b3e1ed | |
| parent | be2b34fa9be31c60a95989f984c9a5d40cd781b6 (diff) | |
randstruct: Enable Clang support
Clang 15 will support randstruct via the -frandomize-layout-seed-file=...
option. Update the Kconfig and Makefile to recognize this feature.
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: linux-kbuild@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220503205503.3054173-7-keescook@chromium.org
| -rw-r--r-- | scripts/Makefile.randstruct | 3 | ||||
| -rw-r--r-- | security/Kconfig.hardening | 14 |
2 files changed, 15 insertions, 2 deletions
diff --git a/scripts/Makefile.randstruct b/scripts/Makefile.randstruct index 4d741e6db554..24e283e89893 100644 --- a/scripts/Makefile.randstruct +++ b/scripts/Makefile.randstruct @@ -7,6 +7,9 @@ randstruct-cflags-y \ += -fplugin=$(objtree)/scripts/gcc-plugins/randomize_layout_plugin.so randstruct-cflags-$(CONFIG_RANDSTRUCT_PERFORMANCE) \ += -fplugin-arg-randomize_layout_plugin-performance-mode +else +randstruct-cflags-y \ + += -frandomize-layout-seed-file=$(objtree)/scripts/basic/randstruct.seed endif export RANDSTRUCT_CFLAGS := $(randstruct-cflags-y) diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index 0277ba578779..bd2aabb2c60f 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -266,9 +266,12 @@ config ZERO_CALL_USED_REGS endmenu +config CC_HAS_RANDSTRUCT + def_bool $(cc-option,-frandomize-layout-seed-file=/dev/null) + choice prompt "Randomize layout of sensitive kernel structures" - default RANDSTRUCT_FULL if COMPILE_TEST && GCC_PLUGINS + default RANDSTRUCT_FULL if COMPILE_TEST && (GCC_PLUGINS || CC_HAS_RANDSTRUCT) default RANDSTRUCT_NONE help If you enable this, the layouts of structures that are entirely @@ -297,13 +300,20 @@ choice config RANDSTRUCT_FULL bool "Fully randomize structure layout" - depends on GCC_PLUGINS + depends on CC_HAS_RANDSTRUCT || GCC_PLUGINS select MODVERSIONS if MODULES help Fully randomize the member layout of sensitive structures as much as possible, which may have both a memory size and performance impact. + One difference between the Clang and GCC plugin + implementations is the handling of bitfields. The GCC + plugin treats them as fully separate variables, + introducing sometimes significant padding. Clang tries + to keep adjacent bitfields together, but with their bit + ordering randomized. + config RANDSTRUCT_PERFORMANCE bool "Limit randomization of structure layout to cache-lines" depends on GCC_PLUGINS |