From fb28a8862dc4b5bf8e44578338f35d9c6c68339d Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 30 Apr 2024 16:49:57 -0700 Subject: lkdtm: Disable CFI checking for perms functions The EXEC_RODATA test plays a lot of tricks to live in the .rodata section, and once again ran into objtool's (completely reasonable) assumptions that executable code should live in an executable section. However, this manifested only under CONFIG_CFI_CLANG=y, as one of the .cfi_sites was pointing into the .rodata section. Since we're testing non-CFI execution properties in perms.c (and rodata.c), we can disable CFI for the involved functions, and remove the CFI arguments from rodata.c entirely. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202308301532.d7acf63e-oliver.sang@intel.com Fixes: 6342a20efbd8 ("objtool: Add elf_create_section_pair()") Link: https://lore.kernel.org/r/20240430234953.work.760-kees@kernel.org Signed-off-by: Kees Cook --- drivers/misc/lkdtm/Makefile | 2 +- drivers/misc/lkdtm/perms.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/misc') diff --git a/drivers/misc/lkdtm/Makefile b/drivers/misc/lkdtm/Makefile index 95ef971b5e1c..b28701138b4b 100644 --- a/drivers/misc/lkdtm/Makefile +++ b/drivers/misc/lkdtm/Makefile @@ -19,7 +19,7 @@ KASAN_SANITIZE_rodata.o := n KCSAN_SANITIZE_rodata.o := n KCOV_INSTRUMENT_rodata.o := n OBJECT_FILES_NON_STANDARD_rodata.o := y -CFLAGS_REMOVE_rodata.o += $(CC_FLAGS_LTO) $(RETHUNK_CFLAGS) +CFLAGS_REMOVE_rodata.o += $(CC_FLAGS_LTO) $(RETHUNK_CFLAGS) $(CC_FLAGS_CFI) OBJCOPYFLAGS := OBJCOPYFLAGS_rodata_objcopy.o := \ diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c index b93404d65650..5b861dbff27e 100644 --- a/drivers/misc/lkdtm/perms.c +++ b/drivers/misc/lkdtm/perms.c @@ -61,7 +61,7 @@ static void *setup_function_descriptor(func_desc_t *fdesc, void *dst) return fdesc; } -static noinline void execute_location(void *dst, bool write) +static noinline __nocfi void execute_location(void *dst, bool write) { void (*func)(void); func_desc_t fdesc; -- cgit v1.2.3