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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 23/26] LSM: Introduce enum lsm_order
Date: Thu, 20 Sep 2018 09:23:35 -0700	[thread overview]
Message-ID: <20180920162338.21060-24-keescook@chromium.org> (raw)
In-Reply-To: <20180920162338.21060-1-keescook@chromium.org>

In preparation for distinguishing the "capability" LSM from other LSMs,
it must be ordered first. This introduces LSM_ORDER_MUTABLE for the
general LSMs, LSM_ORDER_FIRST for capabilities, and LSM_ORDER_LAST for
anything that must run last (e.g. Landlock may use this in the future).

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 include/linux/lsm_hooks.h |  7 +++++++
 security/security.c       | 22 ++++++++++++++++++++--
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index d75a42eb3ddd..bf29851baf47 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -2041,8 +2041,15 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count,
 
 #define LSM_FLAG_LEGACY_MAJOR	(1 << 0)
 
+enum lsm_order {
+	LSM_ORDER_FIRST = -1,	/* This is only for capabilities. */
+	LSM_ORDER_MUTABLE = 0,
+	LSM_ORDER_LAST,
+};
+
 struct lsm_info {
 	const char *name;	/* Populated automatically. */
+	enum lsm_order order;	/* Optional: default is LSM_ORDER_MUTABLE */
 	unsigned long flags;	/* Optional: flags describing LSM */
 	int *enabled;		/* Optional: NULL means enabled. */
 	int (*init)(void);
diff --git a/security/security.c b/security/security.c
index 3fba28de789b..d649e7dea4c4 100644
--- a/security/security.c
+++ b/security/security.c
@@ -62,6 +62,10 @@ static int lsm_enabled_true __initdata = 1;
 static int lsm_enabled_false __initdata = 0;
 static void __init set_enabled(struct lsm_info *lsm, bool enabled)
 {
+	/* First LSM cannot have enablement changed. */
+	if (lsm->order == LSM_ORDER_FIRST)
+		return;
+
 	if (!lsm->enabled) {
 		/*
 		 * If the LSM hasn't configured an enable flag, we
@@ -124,7 +128,8 @@ static void __init parse_lsm_order(const char *order, const char *origin)
 		bool found = false;
 
 		for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
-			if ((lsm->flags & LSM_FLAG_LEGACY_MAJOR) == 0 &&
+			if (lsm->order == LSM_ORDER_MUTABLE &&
+			    (lsm->flags & LSM_FLAG_LEGACY_MAJOR) == 0 &&
 			    strcmp(lsm->name, name) == 0) {
 				append_ordered_lsm(lsm, origin);
 				found = true;
@@ -142,6 +147,12 @@ static void __init prepare_lsm_order(void)
 {
 	struct lsm_info *lsm;
 
+	/* LSM_ORDER_FIRST is always first. */
+	for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
+		if (lsm->order == LSM_ORDER_FIRST)
+			append_ordered_lsm(lsm, "first");
+	}
+
 	/* Parse order from commandline, if present. */
 	if (chosen_lsm_order)
 		parse_lsm_order(chosen_lsm_order, "cmdline");
@@ -151,9 +162,16 @@ static void __init prepare_lsm_order(void)
 
 	/* Add any missing LSMs, in link order. */
 	for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
-		if ((lsm->flags & LSM_FLAG_LEGACY_MAJOR) == 0)
+		if (lsm->order == LSM_ORDER_MUTABLE &&
+		    (lsm->flags & LSM_FLAG_LEGACY_MAJOR) == 0)
 			append_ordered_lsm(lsm, "link-time");
 	}
+
+	/* 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");
+	}
 }
 
 /* Is an LSM allowed to be enabled? */
-- 
2.17.1


  parent reply	other threads:[~2018-09-20 16:30 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 ` [PATCH security-next v2 18/26] LSM: Build ordered list of ordered LSMs for init Kees Cook
2018-09-21  0:04   ` 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 ` Kees Cook [this message]
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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