Commit 42994ee3 authored by Roberto Sassu's avatar Roberto Sassu Committed by Paul Moore
Browse files

security: Introduce LSM_ORDER_LAST and set it for the integrity LSM 



Introduce LSM_ORDER_LAST, to satisfy the requirement of LSMs needing to be
last, e.g. the 'integrity' LSM, without changing the kernel command line or
configuration.

Also, set this order for the 'integrity' LSM. While not enforced, this is
the only LSM expected to use it.

Similarly to LSM_ORDER_FIRST, LSMs with LSM_ORDER_LAST are always enabled
and put at the end of the LSM list, if selected in the kernel
configuration. Setting one of these orders alone, does not cause the LSMs
to be selected and compiled built-in in the kernel.

Finally, for LSM_ORDER_MUTABLE LSMs, set the found variable to true if an
LSM is found, regardless of its order. In this way, the kernel would not
wrongly report that the LSM is not built-in in the kernel if its order is
LSM_ORDER_LAST.

Fixes: 79f7865d ("LSM: Introduce "lsm=" for boottime LSM selection")
Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
Acked-by: default avatarMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent f89f8e16

include/linux/lsm_hooks.h

+1 −0
Original line number Diff line number Diff line
@@ -92,6 +92,7 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count, 
enum lsm_order {

	LSM_ORDER_FIRST = -1,	/* This is only for capabilities. */

	LSM_ORDER_MUTABLE = 0,

	LSM_ORDER_LAST = 1,	/* This is only for integrity. */

};



struct lsm_info {

security/integrity/iint.c

+1 −0
Original line number Diff line number Diff line
@@ -182,6 +182,7 @@ static int __init integrity_iintcache_init(void) 
DEFINE_LSM(integrity) = {

	.name = "integrity",

	.init = integrity_iintcache_init,

	.order = LSM_ORDER_LAST,

};

security/security.c

+9 −3
Original line number Diff line number Diff line
@@ -285,8 +285,8 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) 
		bool found = false;



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

			if (lsm->order == LSM_ORDER_MUTABLE &&

			    strcmp(lsm->name, name) == 0) {

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

				if (lsm->order == LSM_ORDER_MUTABLE)

					append_ordered_lsm(lsm, origin);

				found = true;

			}
@@ -307,6 +307,12 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) 
		}

	}



	/* LSM_ORDER_LAST is always last. */

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

		if (lsm->order == LSM_ORDER_LAST)

			append_ordered_lsm(lsm, "   last");

	}



	/* Disable all LSMs not in the ordered list. */

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

		if (exists_ordered_lsm(lsm))