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From: Kees Cook <keescook@chromium.org>
To: James Morris <jmorris@namei.org>
Cc: Kees Cook <keescook@chromium.org>,
	Casey Schaufler <casey@schaufler-ca.com>,
	John Johansen <john.johansen@canonical.com>,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	Paul Moore <paul@paul-moore.com>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	"Schaufler, Casey" <casey.schaufler@intel.com>,
	LSM <linux-security-module@vger.kernel.org>,
	Jonathan Corbet <corbet@lwn.net>,
	linux-doc@vger.kernel.org, linux-arch@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH security-next v2 18/26] LSM: Build ordered list of ordered LSMs for init
Date: Thu, 20 Sep 2018 09:23:30 -0700	[thread overview]
Message-ID: <20180920162338.21060-19-keescook@chromium.org> (raw)
In-Reply-To: <20180920162338.21060-1-keescook@chromium.org>

This constructs a list of ordered 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: Kees Cook <keescook@chromium.org>
---
 security/security.c | 59 +++++++++++++++++++++++++++++++++++++++------
 1 file changed, 52 insertions(+), 7 deletions(-)

diff --git a/security/security.c b/security/security.c
index 25a019cc4a2b..2541a512a0f7 100644
--- a/security/security.c
+++ b/security/security.c
@@ -34,6 +34,9 @@
 
 #define MAX_LSM_EVM_XATTR	2
 
+/* 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);
 
@@ -41,6 +44,9 @@ char *lsm_names;
 /* Boot-time LSM user choice */
 static __initdata const char *chosen_major_lsm;
 
+/* Ordered list of LSMs to initialize. */
+static __initdata struct lsm_info **ordered_lsms;
+
 static bool debug __initdata;
 #define init_debug(...)						\
 	do {							\
@@ -74,6 +80,45 @@ 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,
+		   (!lsm->enabled || *lsm->enabled) ? "en" : "dis");
+}
+
+/* Populate ordered LSMs list from hard-coded list of LSMs. */
+static void __init prepare_lsm_order(void)
+{
+	struct lsm_info *lsm;
+
+	for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
+		if (strcmp(lsm->name, "integrity") == 0)
+			append_ordered_lsm(lsm, "builtin");
+	}
+}
+
 /* Is an LSM allowed to be enabled? */
 static bool __init lsm_allowed(struct lsm_info *lsm)
 {
@@ -104,14 +149,10 @@ static void __init maybe_initialize_lsm(struct lsm_info *lsm)
 
 static void __init ordered_lsm_init(void)
 {
-	struct lsm_info *lsm;
-
-	for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
-		if ((lsm->flags & LSM_FLAG_LEGACY_MAJOR) != 0)
-			continue;
+	struct lsm_info **lsm;
 
-		maybe_initialize_lsm(lsm);
-	}
+	for (lsm = ordered_lsms; *lsm; lsm++)
+		maybe_initialize_lsm(*lsm);
 }
 
 static void __init major_lsm_init(void)
@@ -141,6 +182,8 @@ int __init security_init(void)
 	for (i = 0; i < sizeof(security_hook_heads) / sizeof(struct hlist_head);
 	     i++)
 		INIT_HLIST_HEAD(&list[i]);
+	ordered_lsms = kcalloc(LSM_COUNT + 1, sizeof(*ordered_lsms),
+				GFP_KERNEL);
 
 	/* Process "security=", if given. */
 	if (!chosen_major_lsm)
@@ -169,6 +212,7 @@ int __init security_init(void)
 	loadpin_add_hooks();
 
 	/* Load LSMs in specified order. */
+	prepare_lsm_order();
 	ordered_lsm_init();
 
 	/*
@@ -176,6 +220,7 @@ int __init security_init(void)
 	 */
 	major_lsm_init();
 
+	kfree(ordered_lsms);
 	return 0;
 }
 
-- 
2.17.1


  parent reply	other threads:[~2018-09-20 16:29 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-20 16:23 [PATCH security-next v2 00/26] LSM: Explict LSM ordering Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 01/26] LSM: Correctly announce start of LSM initialization Kees Cook
2018-09-20 23:39   ` Casey Schaufler
2018-09-20 16:23 ` [PATCH security-next v2 02/26] vmlinux.lds.h: Avoid copy/paste of security_init section Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 03/26] LSM: Rename .security_initcall section to .lsm_info Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 04/26] LSM: Remove initcall tracing Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 05/26] LSM: Convert from initcall to struct lsm_info Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 06/26] vmlinux.lds.h: Move LSM_TABLE into INIT_DATA Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 07/26] LSM: Convert security_initcall() into DEFINE_LSM() Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 08/26] LSM: Record LSM name in struct lsm_info Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 09/26] LSM: Provide init debugging infrastructure Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 10/26] LSM: Don't ignore initialization failures Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 11/26] LSM: Introduce LSM_FLAG_LEGACY_MAJOR Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 12/26] LSM: Provide separate ordered initialization Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 13/26] LSM: Plumb visibility into optional "enabled" state Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 14/26] LSM: Lift LSM selection out of individual LSMs Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 15/26] LSM: Introduce lsm.enable= and lsm.disable= Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 16/26] LSM: Prepare for reorganizing "security=" logic Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 17/26] LSM: Refactor "security=" in terms of enable/disable Kees Cook
2018-09-20 16:23 ` Kees Cook [this message]
2018-09-21  0:04   ` [PATCH security-next v2 18/26] LSM: Build ordered list of ordered LSMs for init Casey Schaufler
2018-09-21  0:37     ` Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 19/26] LSM: Introduce CONFIG_LSM_ORDER Kees Cook
2018-09-21  0:10   ` Casey Schaufler
2018-09-21  0:14     ` Casey Schaufler
2018-09-20 16:23 ` [PATCH security-next v2 20/26] LSM: Introduce "lsm.order=" for boottime ordering Kees Cook
2018-09-21  0:12   ` Casey Schaufler
2018-09-21  0:40     ` Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 21/26] LoadPin: Initialize as ordered LSM Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 22/26] Yama: " Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 23/26] LSM: Introduce enum lsm_order Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 24/26] capability: Mark as LSM_ORDER_FIRST Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 25/26] LSM: Separate idea of "major" LSM from "exclusive" LSM Kees Cook
2018-09-20 16:23 ` [PATCH security-next v2 26/26] LSM: Add all exclusive LSMs to ordered initialization Kees Cook
2018-09-21  0:25   ` Casey Schaufler
2018-09-21  0:45     ` Kees Cook
2018-09-21  1:10       ` Casey Schaufler
2018-09-21  1:39         ` John Johansen
2018-09-21  2:05           ` Kees Cook
2018-09-21  2:14             ` John Johansen
2018-09-21  3:02               ` Kees Cook
2018-09-21 13:19                 ` John Johansen
2018-09-21 14:57                   ` Casey Schaufler
2018-09-20 20:14 ` [PATCH security-next v2 00/26] LSM: Explict LSM ordering Martin Steigerwald
2018-09-20 21:55   ` Kees Cook

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