From acb5a8bee27bf820e50316a328ceec9e24e0d92b Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Fri, 8 Oct 2021 18:58:40 +0200 Subject: [PATCH] lkdtm: Fix content of section containing lkdtm_rodata_do_nothing() commit bc93a22a19eb2b68a16ecf04cdf4b2ed65aaf398 upstream. On a kernel without CONFIG_STRICT_KERNEL_RWX, running EXEC_RODATA test leads to "Illegal instruction" failure. Looking at the content of rodata_objcopy.o, we see that the function content zeroes only: Disassembly of section .rodata: 0000000000000000 <.lkdtm_rodata_do_nothing>: 0: 00 00 00 00 .long 0x0 Add the contents flag in order to keep the content of the section while renaming it. Disassembly of section .rodata: 0000000000000000 <.lkdtm_rodata_do_nothing>: 0: 4e 80 00 20 blr Fixes: e9e08a07385e ("lkdtm: support llvm-objcopy") Cc: stable@vger.kernel.org Cc: Kees Cook Cc: Arnd Bergmann Cc: Greg Kroah-Hartman Cc: Nick Desaulniers Cc: Nathan Chancellor Signed-off-by: Christophe Leroy Reviewed-by: Nick Desaulniers Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/8900731fbc05fb8b0de18af7133a8fc07c3c53a1.1633712176.git.christophe.leroy@csgroup.eu Signed-off-by: Greg Kroah-Hartman --- drivers/misc/lkdtm/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/misc/lkdtm/Makefile b/drivers/misc/lkdtm/Makefile index aa12097668d33..e2984ce51fe4d 100644 --- a/drivers/misc/lkdtm/Makefile +++ b/drivers/misc/lkdtm/Makefile @@ -20,7 +20,7 @@ CFLAGS_REMOVE_rodata.o += $(CC_FLAGS_LTO) OBJCOPYFLAGS := OBJCOPYFLAGS_rodata_objcopy.o := \ - --rename-section .noinstr.text=.rodata,alloc,readonly,load + --rename-section .noinstr.text=.rodata,alloc,readonly,load,contents targets += rodata.o rodata_objcopy.o $(obj)/rodata_objcopy.o: $(obj)/rodata.o FORCE $(call if_changed,objcopy) -- 2.30.2