The documentation for UBSAN_ALIGNMENT already mentions that it should not be used on all*config builds (and for efficient-unaligned-access architectures), so just refactor the Kconfig to correctly implement this so randconfigs will stop creating insane images that freak out objtool under CONFIG_UBSAN_TRAP (due to the false positives producing functions that never return, etc). Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Link: https://lore.kernel.org/linux-next/202004231224.D6B3B650@keescook/ Fixes: 0887a7ebc977 ("ubsan: add trap instrumentation option") Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- lib/Kconfig.ubsan | 15 ++++++--------- .../testing/selftests/wireguard/qemu/debug.config | 1 - 2 files changed, 6 insertions(+), 10 deletions(-) diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan index 48469c95d78e..929211039bac 100644 --- a/lib/Kconfig.ubsan +++ b/lib/Kconfig.ubsan @@ -60,18 +60,15 @@ config UBSAN_SANITIZE_ALL Enabling this option will get kernel image size increased significantly. -config UBSAN_NO_ALIGNMENT - bool "Disable checking of pointers alignment" - default y if HAVE_EFFICIENT_UNALIGNED_ACCESS +config UBSAN_ALIGNMENT + bool "Enable checks for pointers alignment" + default !HAVE_EFFICIENT_UNALIGNED_ACCESS + depends on !X86 || !COMPILE_TEST help - This option disables the check of unaligned memory accesses. - This option should be used when building allmodconfig. - Disabling this option on architectures that support unaligned + This option enables the check of unaligned memory accesses. + Enabling this option on architectures that support unaligned accesses may produce a lot of false positives. -config UBSAN_ALIGNMENT - def_bool !UBSAN_NO_ALIGNMENT - config TEST_UBSAN tristate "Module for testing for undefined behavior detection" depends on m diff --git a/tools/testing/selftests/wireguard/qemu/debug.config b/tools/testing/selftests/wireguard/qemu/debug.config index 807fa7dc60b8..b50c2085c1ac 100644 --- a/tools/testing/selftests/wireguard/qemu/debug.config +++ b/tools/testing/selftests/wireguard/qemu/debug.config @@ -25,7 +25,6 @@ CONFIG_KASAN=y CONFIG_KASAN_INLINE=y CONFIG_UBSAN=y CONFIG_UBSAN_SANITIZE_ALL=y -CONFIG_UBSAN_NO_ALIGNMENT=y CONFIG_UBSAN_NULL=y CONFIG_DEBUG_KMEMLEAK=y CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE=8192 -- 2.20.1 -- Kees Cook
