Messages in this thread | | | From | Nick Desaulniers <> | Date | Wed, 15 May 2019 10:37:31 -0700 | Subject | Re: [PATCH] lkdtm: support llvm-objcopy |
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On Wed, May 15, 2019 at 9:43 AM Kees Cook <keescook@chromium.org> wrote: > > On Tue, May 14, 2019 at 01:24:37PM -0700, Nick Desaulniers wrote: > > On Tue, May 14, 2019 at 11:11 AM Kees Cook <keescook@chromium.org> wrote: > > > > > > On Mon, May 13, 2019 at 04:50:05PM -0700, Nick Desaulniers wrote: > > > > On Mon, May 13, 2019 at 4:29 PM Nathan Chancellor > > > > <natechancellor@gmail.com> wrote: > > > > > > > > > > On Mon, May 13, 2019 at 03:21:09PM -0700, 'Nick Desaulniers' via Clang Built Linux 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. > > > > I'm not sure I want to call it a bug in the initial implementation. I've filed: > > https://sourceware.org/bugzilla/show_bug.cgi?id=24554 for > > clarification. Jordan, I hope you can participate in any discussion > > there? > > Based on the hint from Alan Modra, it seems PROGBITS/NOBITS can be > controlled with the presence/absence of the "load" section flag. This > appears to work for both BFD and LLVM: > > $ objcopy --rename-section .text=.rodata,alloc,readonly,load rodata.o rodata_objcopy.o > $ readelf -WS rodata_objcopy.o | grep \.rodata > [ 1] .rodata PROGBITS 0000000000000000 000040 000002 00 A 0 0 16 > > $ llvm-objcopy --rename-section .text=.rodata,alloc,readonly,load rodata.o rodata_objcopy.o > $ readelf -WS rodata_objcopy.o | grep \.rodata > [ 1] .rodata PROGBITS 0000000000000000 000040 000002 00 A 0 0 16 > > So, that's an easy change that could be folded into the original version > of this patch (no need for my two-phase work-around).
Ah, yes that's better. I'll fold that into a v2 and resend shortly. I'm going to carry your Ack from earlier, please let me know offlist if that's not appropriate. -- Thanks, ~Nick Desaulniers
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