From 14bd99c821f7ace0e8110a1bfdfaa27e1788e20f Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 19 Sep 2018 19:57:06 -0700 Subject: LSM: Separate idea of "major" LSM from "exclusive" LSM In order to both support old "security=" Legacy Major LSM selection, and handling real exclusivity, this creates LSM_FLAG_EXCLUSIVE and updates the selection logic to handle them. Signed-off-by: Kees Cook Reviewed-by: Casey Schaufler --- security/security.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'security/security.c') diff --git a/security/security.c b/security/security.c index 88de6b073246..a8dd7defe30a 100644 --- a/security/security.c +++ b/security/security.c @@ -49,6 +49,7 @@ static __initconst const char * const builtin_lsm_order = CONFIG_LSM; /* Ordered list of LSMs to initialize. */ static __initdata struct lsm_info **ordered_lsms; +static __initdata struct lsm_info *exclusive; static __initdata bool debug; #define init_debug(...) \ @@ -129,6 +130,12 @@ static bool __init lsm_allowed(struct lsm_info *lsm) if (!is_enabled(lsm)) return false; + /* Not allowed if another exclusive LSM already initialized. */ + if ((lsm->flags & LSM_FLAG_EXCLUSIVE) && exclusive) { + init_debug("exclusive disabled: %s\n", lsm->name); + return false; + } + return true; } @@ -144,6 +151,11 @@ static void __init maybe_initialize_lsm(struct lsm_info *lsm) if (enabled) { int ret; + if ((lsm->flags & LSM_FLAG_EXCLUSIVE) && !exclusive) { + exclusive = lsm; + init_debug("exclusive chosen: %s\n", lsm->name); + } + init_debug("initializing %s\n", lsm->name); ret = lsm->init(); WARN(ret, "%s failed to initialize: %d\n", lsm->name, ret); -- cgit v1.2.3