[PATCH v3 2/6] setpriv: dump inheritable capability set

[Ryan Harkin]

Hi Patrick,

On 7 July 2017 at 13:57, Patrick Steinhardt <ps at pks.im> wrote:
> Hi Ryan,
>
> On Fri, Jul 07, 2017 at 01:37:47PM +0100, Ryan Harkin wrote:
>> Hi Patrick/all,
>>
>> I've just updated to the latest BusyBox source and compilation has
>> failed. "git bisect" blamed this patch for the failure.
>>
>> Unfortunately, I have only just subscribed to the mailing list, so
>> this isn't a proper reply to the patch email. For reference, this is
>> the patch I'm referring to:
>>
>>     http://lists.busybox.net/pipermail/busybox/2017-July/085581.html
>>
>> The error I see is:
>>
>>   CC      util-linux/setpriv.o
>> /linaro/platforms/busybox/util-linux/setpriv.c:84:28: fatal error:
>> sys/capability.h: No such file or directory
>>  #include <sys/capability.h>
>>                             ^
>> compilation terminated.
>> /linaro/platforms/busybox/scripts/Makefile.build:197: recipe for
>> target 'util-linux/setpriv.o' failed
>> make[2]: *** [util-linux/setpriv.o] Error 1
>> make[2]: *** Waiting for unfinished jobs....
>> /linaro/platforms/busybox/Makefile:742: recipe for target 'util-linux' failed
>> make[1]: *** [util-linux] Error 2
>> Makefile:112: recipe for target 'install' failed
>> make: *** [install] Error 2
>>
>> I can see that your patch includes sys/capability.h if
>> ENABLE_FEATURE_SETPRIV_CAPABILITIES is defined. And that you are
>> creating a new config called FEATURE_SETPRIV_CAPABILITIES which is
>> enabled by default, so I can see why it's failing for me. However, I
>> don't know how to fix the failure.
>
> You can configure busybox via `make menuconfig`. The setpriv
> feature is located in "util-linux/setpriv", where you can either
> disable the setpriv applet completely or, optionally, just
> support for capabilities.
>

Thanks for showing me that. I figured I could have disabled the
feature somehow. I didn't attempt to as I want to us the upstream code
in its default setup for my builds.


> Anyway -- the failure shouldn't occur at all. The included
> header is not even used as we're only using defines from
> <linux/capability.h> and prctl, which are provided by
> linux-headers and your libc implementation. I'll send a patch
> shortly. Thanks for noticing the failure.
>

Great, thanks again.

I'm happy to test the patch in my setup if you would like an extra
reviewed or tested-by tag.

>> This is how I build BusyBox:
>>
>> export ARCH=arm
>> export CROSS_COMPILE=<path to arm-linux-gnueabihf-* v6.2.1>
>> mkdir -p $BUSYBOX_OUT_DIR
>> make O=$BUSYBOX_OUT_DIR defconfig
>> sed -i 's/# CONFIG_STATIC is not set/CONFIG_STATIC=y/g' $BUSYBOX_OUT_DIR/.config
>> make O=$BUSYBOX_OUT_DIR -j $PARALLELISM install
>>
>> A web search around the topic implies that installing libcap-dev will
>> resolve the dependency, but this doesn't help on my Ubuntu 16.04 LTS
>> system. It does install /usr/include/sys/capability.h, so it's doing
>> something. However, as I'm cross compiling, perhaps there is an extra
>> make param I need to add or something else I need to install? The
>> build works if I compile native for my x86_64 machine.
>>
>> So I'm at a loss on how to proceed from there. Any help would be appreciated.
>>
>> Regards,
>> Ryan.
>
> Regards
> Patrick