| From e9e08a07385e08f1a7f85c5d1e345c21c9564963 Mon Sep 17 00:00:00 2001 |
| From: Nick Desaulniers <ndesaulniers@google.com> |
| Date: Wed, 15 May 2019 11:24:41 -0700 |
| Subject: lkdtm: support llvm-objcopy |
| |
| From: Nick Desaulniers <ndesaulniers@google.com> |
| |
| commit e9e08a07385e08f1a7f85c5d1e345c21c9564963 upstream. |
| |
| 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 <natechancellor@gmail.com> |
| Suggested-by: Alan Modra <amodra@gmail.com> |
| Suggested-by: Jordan Rupprect <rupprecht@google.com> |
| Suggested-by: Kees Cook <keescook@chromium.org> |
| Acked-by: Kees Cook <keescook@chromium.org> |
| Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> |
| Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| commit e9e08a07385e08f1a7f85c5d1e345c21c9564963 upstream. |
| |
| 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 <natechancellor@gmail.com> |
| Suggested-by: Alan Modra <amodra@gmail.com> |
| Suggested-by: Jordan Rupprect <rupprecht@google.com> |
| Suggested-by: Kees Cook <keescook@chromium.org> |
| Acked-by: Kees Cook <keescook@chromium.org> |
| Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> |
| Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/misc/Makefile | 3 +-- |
| 1 file changed, 1 insertion(+), 2 deletions(-) |
| |
| --- a/drivers/misc/Makefile |
| +++ b/drivers/misc/Makefile |
| @@ -69,8 +69,7 @@ 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) |