On Mon, May 13, 2019 at 03:21:09PM -0700, Nick Desaulniers wrote: > 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. > > 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 in the Flags field that .text is now renamed .rodata, the > append flag A is set, and the section is not flagged as writeable W. > > Link: https://github.com/ClangBuiltLinux/linux/issues/448 > Reported-by: Nathan Chancellor <nathancha...@gmail.com> > Suggested-by: Jordan Rupprect <ruppre...@google.com> > Signed-off-by: Nick Desaulniers <ndesaulni...@google.com>
Thanks! This looks good. Greg, can you please take this for drivers/misc? Acked-by: Kees Cook <keesc...@chromium.org> -Kees > --- > drivers/misc/lkdtm/Makefile | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/misc/lkdtm/Makefile b/drivers/misc/lkdtm/Makefile > index 951c984de61a..89dee2a9d88c 100644 > --- a/drivers/misc/lkdtm/Makefile > +++ b/drivers/misc/lkdtm/Makefile > @@ -15,8 +15,7 @@ KCOV_INSTRUMENT_rodata.o := n > > OBJCOPYFLAGS := > OBJCOPYFLAGS_rodata_objcopy.o := \ > - --set-section-flags .text=alloc,readonly \ > - --rename-section .text=.rodata > + --rename-section .text=.rodata,alloc,readonly > targets += rodata.o rodata_objcopy.o > $(obj)/rodata_objcopy.o: $(obj)/rodata.o FORCE > $(call if_changed,objcopy) > -- > 2.21.0.1020.gf2820cf01a-goog > -- Kees Cook
