[PATCH v2 6/8] selinux: do not include <linux/*.h> headers from host programs

[Paul Moore]

On Fri, Sep 6, 2024 at 7:01 AM Daniel Gomez via B4 Relay
<devnull+da.gomez.samsung.com at kernel.org> wrote:
>
> From: Masahiro Yamada <masahiroy at kernel.org>
>
> Commit bfc5e3a6af39 ("selinux: use the kernel headers when building
> scripts/selinux") is not the right thing to do.
>
> It is clear from the warning in include/uapi/linux/types.h:
>
>   #ifndef __EXPORTED_HEADERS__
>   #warning "Attempt to use kernel headers from user space, see https://kernelnewbies.org/KernelHeaders"
>   #endif /* __EXPORTED_HEADERS__ */
>
> If you are inclined to define __EXPORTED_HEADERS__, you are likely doing
> wrong.
>
> Adding the comment:
>
>   /* NOTE: we really do want to use the kernel headers here */
>
> does not justify the hack in any way.
>
> Currently, <linux/*.h> headers are included for the following purposes:
>
>  - <linux/capability.h> is included to check CAP_LAST_CAP
>  - <linux/socket.h> in included to check PF_MAX
>
> We can skip these checks when building host programs, as they will
> be eventually tested when building the kernel space.
>
> I got rid of <linux/stddef.h> from initial_sid_to_string.h because
> it is likely that NULL is already defined. If you insist on making
> it self-contained, you can add the following:
>
>   #ifdef __KERNEL__
>   #include <linux/stddef.h>
>   #else
>   #include <stddef.h>
>   #endif
>
> scripts/selinux/mdp/mdp.c still includes <linux/kconfig.h>, which is
> also discouraged and should be fixed by a follow-up refactoring.
>
> Signed-off-by: Masahiro Yamada <masahiroy at kernel.org>
> ---
>  scripts/selinux/genheaders/Makefile              |  4 +---
>  scripts/selinux/genheaders/genheaders.c          |  3 ---
>  scripts/selinux/mdp/Makefile                     |  2 +-
>  scripts/selinux/mdp/mdp.c                        |  4 ----
>  security/selinux/include/classmap.h              | 19 ++++++++++++-------
>  security/selinux/include/initial_sid_to_string.h |  2 --
>  6 files changed, 14 insertions(+), 20 deletions(-)

Similar to patch 7/8, please read my comments on your previous posting
of this patch, it doesn't appear that you've made any of the changes I
asked for in your previous posting.

https://lore.kernel.org/selinux/317c7d20ab8a72975571cb554589522b@paul-moore.com

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