>From 10c0a74a8d92669b91b66efe6b72550fc24e8e7d Mon Sep 17 00:00:00 2001 From: Nick Desaulniers Date: Wed, 15 May 2019 11:24:41 -0700 Subject: [PATCH] lkdtm: support llvm-objcopy With CONFIG_LKDTM=y and make OBJCOPY=llvm-objcopy, llvm-objcopy errors: llvm-objcopy: error: --set-section-flags=.text conflicts with --rename-section=.text=.rodata Rather than support setting flags then renaming sections vs renaming then setting flags, it's simpler to just change both at the same time via --rename-section. Adding the load flag is required for GNU objcopy to mark .rodata Type as PROGBITS after the rename. This can be verified with: $ readelf -S drivers/misc/lkdtm/rodata_objcopy.o ... Section Headers: [Nr] Name Type Address Offset Size EntSize Flags Link Info Align ... [ 1] .rodata PROGBITS 0000000000000000 00000040 0000000000000004 0000000000000000 A 0 0 4 ... Which shows that .text is now renamed .rodata, the alloc flag A is set, the type is PROGBITS, and the section is not flagged as writeable W. Cc: stable@vger.kernel.org Link: https://sourceware.org/bugzilla/show_bug.cgi?id=24554 Link: https://github.com/ClangBuiltLinux/linux/issues/448 Reported-by: Nathan Chancellor Suggested-by: Alan Modra Suggested-by: Jordan Rupprect Suggested-by: Kees Cook Acked-by: Kees Cook Reviewed-by: Nathan Chancellor Signed-off-by: Nick Desaulniers Signed-off-by: Nathan Chancellor --- drivers/misc/Makefile | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index c3c8624f4d95..805835c2b99b 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -70,8 +70,7 @@ KCOV_INSTRUMENT_lkdtm_rodata.o := n OBJCOPYFLAGS := OBJCOPYFLAGS_lkdtm_rodata_objcopy.o := \ - --set-section-flags .text=alloc,readonly \ - --rename-section .text=.rodata + --rename-section .text=.rodata,alloc,readonly,load targets += lkdtm_rodata.o lkdtm_rodata_objcopy.o $(obj)/lkdtm_rodata_objcopy.o: $(obj)/lkdtm_rodata.o FORCE $(call if_changed,objcopy) -- 2.22.0.rc0