From 79f7865d844c7703e3dc0e2f5b9ed2f3a4f412e5 Mon Sep 17 00:00:00 2001 From: Kees Cook 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 --- 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 b799bcf67d7b5a..e59e1471d4db8d 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 7f21190cb6774c..cedf69e8a22c85 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 11a42cd313c5ab..2e1f48e8a6f2bf 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) {