Re: [PATCH v5 3/5] security: Replace indirect LSM hook calls with static calls

[Kees Cook <keescook@chromium.org>]

On Sun, Oct 01, 2023 at 12:13:06AM +0800, kernel test robot wrote:
> Hi KP,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on bpf-next/master]
> [also build test ERROR on bpf/master pcmoore-selinux/next linus/master v6.6-rc3 next-20230929]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/KP-Singh/kernel-Add-helper-macros-for-loop-unrolling/20230929-042610
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
> patch link:    https://lore.kernel.org/r/20230928202410.3765062-4-kpsingh%40kernel.org
> patch subject: [PATCH v5 3/5] security: Replace indirect LSM hook calls with static calls
> config: i386-randconfig-001-20230930 (https://download.01.org/0day-ci/archive/20230930/202309302332.1mxVwb0U-lkp@intel.com/config)
> compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230930/202309302332.1mxVwb0U-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202309302332.1mxVwb0U-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
> >> security/security.c:139:1: error: Only string constants are supported as initializers for randomized structures with flexible arrays
>      139 | };
>          | ^

Uuh, where is there a flexible array here?

> vim +139 security/security.c
> 
>    118	
>    119	/*
>    120	 * Initialise a table of static calls for each LSM hook.
>    121	 * DEFINE_STATIC_CALL_NULL invocation above generates a key (STATIC_CALL_KEY)
>    122	 * and a trampoline (STATIC_CALL_TRAMP) which are used to call
>    123	 * __static_call_update when updating the static call.
>    124	 */
>    125	struct lsm_static_calls_table static_calls_table __ro_after_init = {
>    126	#define INIT_LSM_STATIC_CALL(NUM, NAME)					\
>    127		(struct lsm_static_call) {					\
>    128			.key = &STATIC_CALL_KEY(LSM_STATIC_CALL(NAME, NUM)),	\
>    129			.trampoline = LSM_HOOK_TRAMP(NAME, NUM),		\
>    130			.active = &SECURITY_HOOK_ACTIVE_KEY(NAME, NUM),		\
>    131		},
>    132	#define LSM_HOOK(RET, DEFAULT, NAME, ...)				\
>    133		.NAME = {							\
>    134			LSM_DEFINE_UNROLL(INIT_LSM_STATIC_CALL, NAME)		\
>    135		},
>    136	#include <linux/lsm_hook_defs.h>
>    137	#undef LSM_HOOK
>    138	#undef INIT_LSM_STATIC_CALL
>  > 139	};
>    140	

*confused*

-Kees

-- 
Kees Cook