Re: [PATCH]: cross-compiling x86_64 kernel on i386 user-space fails

From: Kees Cook
Date: Sat Nov 22 2014 - 11:00:37 EST


On Sat, Nov 22, 2014 at 3:14 AM, Borislav Petkov <bp@xxxxxxxxx> wrote:
> On Sat, Nov 22, 2014 at 09:51:10AM +0000, Chris Clayton wrote:
>> Hi,
>
> Yeah, next time make sure you actually CC people :-)
>
> I've added them to CC now.
>
>> Commit e6023367d779060fddc9a52d1f474085b2b36298 broke building an x86_64 kernel in an i386. The change added a call to
>> objdump but neglected to cater for cross-compiling.
>>
>> The patch below fixes the problem for me. I see the commit is now in 3.14 and 3.17 -stable, so the patch needs to go
>> there too.

Good catch, thanks!

>
> CC: stable@xxxxxxxxxxxxxxx
>
> in the commit message should help there.
>
>
>> CC: Junjie Mao <eternal.n08@xxxxxxxxx>
>> CC: Kees Cook <keescook@xxxxxxxxxxxx>
>> CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> CC: Ingo Molnar <mingo@xxxxxxxxxx>
>> Signed-off-by: Chris Clayton <chris2553@xxxxxxxxxxxxxx>
>
> Acked-by: Borislav Petkov <bp@xxxxxxx>

Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>

-Kees

>
>> ---
>> --- linux/arch/x86/boot/compressed/Makefile~ 2014-11-22 08:56:50.359706324 +0000
>> +++ linux/arch/x86/boot/compressed/Makefile 2014-11-22 09:04:06.615693435 +0000
>> @@ -76,7 +76,7 @@ suffix-$(CONFIG_KERNEL_XZ) := xz
>> suffix-$(CONFIG_KERNEL_LZO) := lzo
>> suffix-$(CONFIG_KERNEL_LZ4) := lz4
>>
>> -RUN_SIZE = $(shell objdump -h vmlinux | \
>> +RUN_SIZE = $(shell ${CROSS_COMPILE}objdump -h vmlinux | \
>> perl $(srctree)/arch/x86/tools/calc_run_size.pl)
>> quiet_cmd_mkpiggy = MKPIGGY $@
>> cmd_mkpiggy = $(obj)/mkpiggy $< $(RUN_SIZE) > $@ || ( rm -f $@ ; false )
>>
>> --
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>
> --
> Regards/Gruss,
> Boris.
>
> Sent from a fat crate under my desk. Formatting is fine.
> --



--
Kees Cook
Chrome OS Security
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