[PATCH] samples/seccomp: Add standalone config option

[PATCH] samples/seccomp: Add standalone config option

[Olof Johansson]

Add a separate Kconfig option for SAMPLES_SECCOMP.

Main reason for this is that, just like other samples, it's forced to be a module.

Without this, since the sample is a target only controlled by
CONFIG_SECCOMP_FILTER, the samples will be built before include files are
put in place properly. For example, from an arm64 allmodconfig built with
"make -sk -j 32" (without specific target), the following happens:

samples/seccomp/bpf-fancy.c:13:27: fatal error: linux/seccomp.h: No such file or directory
samples/seccomp/bpf-helper.h:20:50: fatal error: linux/seccomp.h: No such file or directory
samples/seccomp/dropper.c:20:27: fatal error: linux/seccomp.h: No such file or directory
samples/seccomp/bpf-direct.c:21:27: fatal error: linux/seccomp.h: No such file or directory

So, just stick to the same format as other samples.

Signed-off-by: Olof Johansson <olof@lixom.net>
---
 samples/Kconfig          | 7 +++++++
 samples/seccomp/Makefile | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)


Hi Kees,

This has been showing up for a while on my builder, and I finally had
a bit of time to sit down and look at it.

It'd be nice to see this in 4.7, but please consider for 4.8 at the least.


Thanks!

-Olof

diff --git a/samples/Kconfig b/samples/Kconfig
index 559a58b..ccc50be 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -85,4 +85,11 @@ config SAMPLE_CONNECTOR
 	  with it.
 	  See also Documentation/connector/connector.txt
 
+config SAMPLE_SECCOMP
+	tristate "Build seccomp sample code -- loadable modules only"
+	depends on SECCOMP_FILTER && m
+	help
+	  Build samples of seccomp filters using various methods of
+	  BPF filter construction.
+
 endif # SAMPLES
diff --git a/samples/seccomp/Makefile b/samples/seccomp/Makefile
index 1b4e4b8..ae7ff6f 100644
--- a/samples/seccomp/Makefile
+++ b/samples/seccomp/Makefile
@@ -1,7 +1,7 @@
 # kbuild trick to avoid linker error. Can be omitted if a module is built.
 obj- := dummy.o
 
-hostprogs-$(CONFIG_SECCOMP_FILTER) := bpf-fancy dropper bpf-direct
+hostprogs-$(CONFIG_SAMPLE_SECCOMP) := bpf-fancy dropper bpf-direct
 
 HOSTCFLAGS_bpf-fancy.o += -I$(objtree)/usr/include
 HOSTCFLAGS_bpf-fancy.o += -idirafter $(objtree)/include
-- 
2.8.0.rc3.29.gb552ff8

Re: [PATCH] samples/seccomp: Add standalone config option

[Kees Cook]

On Wed, Jul 6, 2016 at 2:53 AM, Olof Johansson <olof@lixom.net> wrote:
> Add a separate Kconfig option for SAMPLES_SECCOMP.
>
> Main reason for this is that, just like other samples, it's forced to be a module.
>
> Without this, since the sample is a target only controlled by
> CONFIG_SECCOMP_FILTER, the samples will be built before include files are
> put in place properly. For example, from an arm64 allmodconfig built with
> "make -sk -j 32" (without specific target), the following happens:
>
> samples/seccomp/bpf-fancy.c:13:27: fatal error: linux/seccomp.h: No such file or directory
> samples/seccomp/bpf-helper.h:20:50: fatal error: linux/seccomp.h: No such file or directory
> samples/seccomp/dropper.c:20:27: fatal error: linux/seccomp.h: No such file or directory
> samples/seccomp/bpf-direct.c:21:27: fatal error: linux/seccomp.h: No such file or directory

Ah-ha! Yes, that's ugly.

> So, just stick to the same format as other samples.

Agreed, that makes sense to me.

>
> Signed-off-by: Olof Johansson <olof@lixom.net>
> ---
>  samples/Kconfig          | 7 +++++++
>  samples/seccomp/Makefile | 2 +-
>  2 files changed, 8 insertions(+), 1 deletion(-)
>
>
> Hi Kees,
>
> This has been showing up for a while on my builder, and I finally had
> a bit of time to sit down and look at it.
>
> It'd be nice to see this in 4.7, but please consider for 4.8 at the least.
>
>
> Thanks!
>
> -Olof
>
> diff --git a/samples/Kconfig b/samples/Kconfig
> index 559a58b..ccc50be 100644
> --- a/samples/Kconfig
> +++ b/samples/Kconfig
> @@ -85,4 +85,11 @@ config SAMPLE_CONNECTOR
>           with it.
>           See also Documentation/connector/connector.txt
>
> +config SAMPLE_SECCOMP
> +       tristate "Build seccomp sample code -- loadable modules only"
> +       depends on SECCOMP_FILTER && m
> +       help
> +         Build samples of seccomp filters using various methods of
> +         BPF filter construction.
> +
>  endif # SAMPLES
> diff --git a/samples/seccomp/Makefile b/samples/seccomp/Makefile
> index 1b4e4b8..ae7ff6f 100644
> --- a/samples/seccomp/Makefile
> +++ b/samples/seccomp/Makefile
> @@ -1,7 +1,7 @@
>  # kbuild trick to avoid linker error. Can be omitted if a module is built.
>  obj- := dummy.o

Can the above two lines be dropped now since it'll always be a module?

>
> -hostprogs-$(CONFIG_SECCOMP_FILTER) := bpf-fancy dropper bpf-direct
> +hostprogs-$(CONFIG_SAMPLE_SECCOMP) := bpf-fancy dropper bpf-direct
>
>  HOSTCFLAGS_bpf-fancy.o += -I$(objtree)/usr/include
>  HOSTCFLAGS_bpf-fancy.o += -idirafter $(objtree)/include
> --
> 2.8.0.rc3.29.gb552ff8
>

-Kees

-- 
Kees Cook
Chrome OS & Brillo Security

Re: [PATCH] samples/seccomp: Add standalone config option

[Olof Johansson]

Hi,

On Wed, Jul 6, 2016 at 10:55 AM, Kees Cook <keescook@chromium.org> wrote:
> On Wed, Jul 6, 2016 at 2:53 AM, Olof Johansson <olof@lixom.net> wrote:
>> Add a separate Kconfig option for SAMPLES_SECCOMP.
>>
>> Main reason for this is that, just like other samples, it's forced to be a module.
>>
>> Without this, since the sample is a target only controlled by
>> CONFIG_SECCOMP_FILTER, the samples will be built before include files are
>> put in place properly. For example, from an arm64 allmodconfig built with
>> "make -sk -j 32" (without specific target), the following happens:
>>
>> samples/seccomp/bpf-fancy.c:13:27: fatal error: linux/seccomp.h: No such file or directory
>> samples/seccomp/bpf-helper.h:20:50: fatal error: linux/seccomp.h: No such file or directory
>> samples/seccomp/dropper.c:20:27: fatal error: linux/seccomp.h: No such file or directory
>> samples/seccomp/bpf-direct.c:21:27: fatal error: linux/seccomp.h: No such file or directory
>
> Ah-ha! Yes, that's ugly.
>
>> So, just stick to the same format as other samples.
>
> Agreed, that makes sense to me.
>
>>
>> Signed-off-by: Olof Johansson <olof@lixom.net>
>> ---
>>  samples/Kconfig          | 7 +++++++
>>  samples/seccomp/Makefile | 2 +-
>>  2 files changed, 8 insertions(+), 1 deletion(-)
>>
>>
>> Hi Kees,
>>
>> This has been showing up for a while on my builder, and I finally had
>> a bit of time to sit down and look at it.
>>
>> It'd be nice to see this in 4.7, but please consider for 4.8 at the least.
>>
>>
>> Thanks!
>>
>> -Olof
>>
>> diff --git a/samples/Kconfig b/samples/Kconfig
>> index 559a58b..ccc50be 100644
>> --- a/samples/Kconfig
>> +++ b/samples/Kconfig
>> @@ -85,4 +85,11 @@ config SAMPLE_CONNECTOR
>>           with it.
>>           See also Documentation/connector/connector.txt
>>
>> +config SAMPLE_SECCOMP
>> +       tristate "Build seccomp sample code -- loadable modules only"
>> +       depends on SECCOMP_FILTER && m
>> +       help
>> +         Build samples of seccomp filters using various methods of
>> +         BPF filter construction.
>> +
>>  endif # SAMPLES
>> diff --git a/samples/seccomp/Makefile b/samples/seccomp/Makefile
>> index 1b4e4b8..ae7ff6f 100644
>> --- a/samples/seccomp/Makefile
>> +++ b/samples/seccomp/Makefile
>> @@ -1,7 +1,7 @@
>>  # kbuild trick to avoid linker error. Can be omitted if a module is built.
>>  obj- := dummy.o
>
> Can the above two lines be dropped now since it'll always be a module?

Actually, they can't, since the only other target is a hostprogs one.
Still needs a dummy module object file.


-Olof

Re: [PATCH] samples/seccomp: Add standalone config option

[Kees Cook]

On Wed, Jul 6, 2016 at 2:53 AM, Olof Johansson <olof@lixom.net> wrote:
> Add a separate Kconfig option for SAMPLES_SECCOMP.
>
> Main reason for this is that, just like other samples, it's forced to be a module.
>
> Without this, since the sample is a target only controlled by
> CONFIG_SECCOMP_FILTER, the samples will be built before include files are
> put in place properly. For example, from an arm64 allmodconfig built with
> "make -sk -j 32" (without specific target), the following happens:
>
> samples/seccomp/bpf-fancy.c:13:27: fatal error: linux/seccomp.h: No such file or directory
> samples/seccomp/bpf-helper.h:20:50: fatal error: linux/seccomp.h: No such file or directory
> samples/seccomp/dropper.c:20:27: fatal error: linux/seccomp.h: No such file or directory
> samples/seccomp/bpf-direct.c:21:27: fatal error: linux/seccomp.h: No such file or directory
>
> So, just stick to the same format as other samples.
>
> Signed-off-by: Olof Johansson <olof@lixom.net>
> ---
>  samples/Kconfig          | 7 +++++++
>  samples/seccomp/Makefile | 2 +-
>  2 files changed, 8 insertions(+), 1 deletion(-)
>
>
> Hi Kees,
>
> This has been showing up for a while on my builder, and I finally had
> a bit of time to sit down and look at it.
>
> It'd be nice to see this in 4.7, but please consider for 4.8 at the least.

I feel like we're too late in 4.7, but I've applied this for 4.8.
Thanks for tracking it down!

-Kees

>
>
> Thanks!
>
> -Olof
>
> diff --git a/samples/Kconfig b/samples/Kconfig
> index 559a58b..ccc50be 100644
> --- a/samples/Kconfig
> +++ b/samples/Kconfig
> @@ -85,4 +85,11 @@ config SAMPLE_CONNECTOR
>           with it.
>           See also Documentation/connector/connector.txt
>
> +config SAMPLE_SECCOMP
> +       tristate "Build seccomp sample code -- loadable modules only"
> +       depends on SECCOMP_FILTER && m
> +       help
> +         Build samples of seccomp filters using various methods of
> +         BPF filter construction.
> +
>  endif # SAMPLES
> diff --git a/samples/seccomp/Makefile b/samples/seccomp/Makefile
> index 1b4e4b8..ae7ff6f 100644
> --- a/samples/seccomp/Makefile
> +++ b/samples/seccomp/Makefile
> @@ -1,7 +1,7 @@
>  # kbuild trick to avoid linker error. Can be omitted if a module is built.
>  obj- := dummy.o
>
> -hostprogs-$(CONFIG_SECCOMP_FILTER) := bpf-fancy dropper bpf-direct
> +hostprogs-$(CONFIG_SAMPLE_SECCOMP) := bpf-fancy dropper bpf-direct
>
>  HOSTCFLAGS_bpf-fancy.o += -I$(objtree)/usr/include
>  HOSTCFLAGS_bpf-fancy.o += -idirafter $(objtree)/include
> --
> 2.8.0.rc3.29.gb552ff8
>



-- 
Kees Cook
Chrome OS & Brillo Security