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Commit 2d4d5119 authored by Kees Cook's avatar Kees Cook
Browse files

LSM: Build ordered list of LSMs to initialize 



This constructs an ordered list of LSMs to initialize, using a hard-coded
list of only "integrity": minor LSMs continue to have direct hook calls,
and major LSMs continue to initialize separately.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarCasey Schaufler <casey@schaufler-ca.com>
parent f4941d75

security/security.c

+53 −5
Original line number Diff line number Diff line
@@ -37,6 +37,9 @@ 
/* Maximum number of letters for an LSM name string */

#define SECURITY_NAME_MAX	10



/* How many LSMs were built into the kernel? */

#define LSM_COUNT (__end_lsm_info - __start_lsm_info)



struct security_hook_heads security_hook_heads __lsm_ro_after_init;

static ATOMIC_NOTIFIER_HEAD(lsm_notifier_chain);
@@ -45,6 +48,9 @@ char *lsm_names; 
static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =

	CONFIG_DEFAULT_SECURITY;



/* Ordered list of LSMs to initialize. */

static __initdata struct lsm_info **ordered_lsms;



static __initdata bool debug;

#define init_debug(...)						\

	do {							\
@@ -85,6 +91,34 @@ static void __init set_enabled(struct lsm_info *lsm, bool enabled) 
	}

}



/* Is an LSM already listed in the ordered LSMs list? */

static bool __init exists_ordered_lsm(struct lsm_info *lsm)

{

	struct lsm_info **check;



	for (check = ordered_lsms; *check; check++)

		if (*check == lsm)

			return true;



	return false;

}



/* Append an LSM to the list of ordered LSMs to initialize. */

static int last_lsm __initdata;

static void __init append_ordered_lsm(struct lsm_info *lsm, const char *from)

{

	/* Ignore duplicate selections. */

	if (exists_ordered_lsm(lsm))

		return;



	if (WARN(last_lsm == LSM_COUNT, "%s: out of LSM slots!?\n", from))

		return;



	ordered_lsms[last_lsm++] = lsm;

	init_debug("%s ordering: %s (%sabled)\n", from, lsm->name,

		   is_enabled(lsm) ? "en" : "dis");

}



/* Is an LSM allowed to be initialized? */

static bool __init lsm_allowed(struct lsm_info *lsm)

{
@@ -121,16 +155,30 @@ static void __init maybe_initialize_lsm(struct lsm_info *lsm) 
	}

}



static void __init ordered_lsm_init(void)

/* Populate ordered LSMs list from single LSM name. */

static void __init ordered_lsm_parse(const char *order, const char *origin)

{

	struct lsm_info *lsm;



	for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {

		if ((lsm->flags & LSM_FLAG_LEGACY_MAJOR) != 0)

			continue;



		maybe_initialize_lsm(lsm);

		if (strcmp(lsm->name, order) == 0)

			append_ordered_lsm(lsm, origin);

	}

}



static void __init ordered_lsm_init(void)

{

	struct lsm_info **lsm;



	ordered_lsms = kcalloc(LSM_COUNT + 1, sizeof(*ordered_lsms),

				GFP_KERNEL);



	ordered_lsm_parse("integrity", "builtin");



	for (lsm = ordered_lsms; *lsm; lsm++)

		maybe_initialize_lsm(*lsm);



	kfree(ordered_lsms);

}



static void __init major_lsm_init(void)