From 79f7865d844c7703e3dc0e2f5b9ed2f3a4f412e5 Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Wed, 19 Sep 2018 17:30:09 -0700
Subject: [PATCH] LSM: Introduce "lsm=" for boottime LSM selection
Provide a way to explicitly choose LSM initialization order via the new
"lsm=" comma-separated list of LSMs.
Signed-off-by: Kees Cook <keescook@chromium.org>
---
Documentation/admin-guide/kernel-parameters.txt | 4 ++++
security/Kconfig | 3 ++-
security/security.c | 14 +++++++++++++-
3 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index b799bcf67d7b5..e59e1471d4db8 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2319,6 +2319,10 @@
lsm.debug [SECURITY] Enable LSM initialization debugging output.
+ lsm=lsm1,...,lsmN
+ [SECURITY] Choose order of LSM initialization. This
+ overrides CONFIG_LSM.
+
machvec= [IA-64] Force the use of a particular machine-vector
(machvec) in a generic kernel.
Example: machvec=hpzx1_swiotlb
diff --git a/security/Kconfig b/security/Kconfig
index 7f21190cb6774..cedf69e8a22c8 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -281,7 +281,8 @@ config LSM
default "integrity"
help
A comma-separated list of LSMs, in initialization order.
- Any LSMs left off this list will be ignored.
+ Any LSMs left off this list will be ignored. This can be
+ controlled at boot with the "lsm=" parameter.
If unsure, leave this as the default.
diff --git a/security/security.c b/security/security.c
index 11a42cd313c5a..2e1f48e8a6f2b 100644
--- a/security/security.c
+++ b/security/security.c
@@ -47,6 +47,7 @@ char *lsm_names;
/* Boot-time LSM user choice */
static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =
CONFIG_DEFAULT_SECURITY;
+static __initdata const char *chosen_lsm_order;
static __initconst const char * const builtin_lsm_order = CONFIG_LSM;
@@ -190,7 +191,10 @@ static void __init ordered_lsm_init(void)
ordered_lsms = kcalloc(LSM_COUNT + 1, sizeof(*ordered_lsms),
GFP_KERNEL);
- ordered_lsm_parse(builtin_lsm_order, "builtin");
+ if (chosen_lsm_order)
+ ordered_lsm_parse(chosen_lsm_order, "cmdline");
+ else
+ ordered_lsm_parse(builtin_lsm_order, "builtin");
for (lsm = ordered_lsms; *lsm; lsm++)
maybe_initialize_lsm(*lsm);
@@ -252,6 +256,14 @@ static int __init choose_lsm(char *str)
}
__setup("security=", choose_lsm);
+/* Explicitly choose LSM initialization order. */
+static int __init choose_lsm_order(char *str)
+{
+ chosen_lsm_order = str;
+ return 1;
+}
+__setup("lsm=", choose_lsm_order);
+
/* Enable LSM order debugging. */
static int __init enable_debug(char *str)
{
--
GitLab