[PATCH security-next v4 31/32] LSM: Separate idea of "major" LSM from "exclusive" LSM
From: Kees Cook <hidden>
Date: 2018-10-02 00:55:44
Also in:
linux-arch, linux-security-module, lkml
Subsystem:
apparmor security module, security subsystem, selinux security module, smack security module, the rest, tomoyo security module · Maintainers:
John Johansen, Georgia Garcia, Paul Moore, James Morris, "Serge E. Hallyn", Stephen Smalley, Casey Schaufler, Linus Torvalds, Kentaro Takeda, Tetsuo Handa
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 <redacted> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> --- include/linux/lsm_hooks.h | 1 + security/apparmor/lsm.c | 2 +- security/security.c | 12 ++++++++++++ security/selinux/hooks.c | 2 +- security/smack/smack_lsm.c | 2 +- security/tomoyo/tomoyo.c | 2 +- 6 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 36e7a716fdfe..2c9cf89a20ad 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h@@ -2040,6 +2040,7 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count, char *lsm); #define LSM_FLAG_LEGACY_MAJOR BIT(0) +#define LSM_FLAG_EXCLUSIVE BIT(1) enum lsm_order { LSM_ORDER_FIRST = -1, /* This is only for capabilities. */
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 4cd96a66ed6f..4eb74a6f2020 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c@@ -1599,7 +1599,7 @@ static int __init apparmor_init(void) DEFINE_LSM(apparmor) = { .name = "apparmor", - .flags = LSM_FLAG_LEGACY_MAJOR, + .flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE, .enabled = &apparmor_enabled, .init = apparmor_init, };
diff --git a/security/security.c b/security/security.c
index 813dab3b5b97..7d542e78b7e8 100644
--- a/security/security.c
+++ b/security/security.c@@ -52,6 +52,7 @@ static __initconst const char * const builtin_lsm_order = CONFIG_LSM_ORDER; /* 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(...) \
@@ -196,6 +197,12 @@ 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; }
@@ -211,6 +218,11 @@ 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: %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);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 8f5eea097612..c070d3761ddc 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c@@ -7181,7 +7181,7 @@ void selinux_complete_init(void) all processes and objects when they are created. */ DEFINE_LSM(selinux) = { .name = "selinux", - .flags = LSM_FLAG_LEGACY_MAJOR, + .flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE, .enabled = &selinux_enabled, .init = selinux_init, };
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index f243044d5a55..92e4baa342f8 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c@@ -4881,6 +4881,6 @@ static __init int smack_init(void) */ DEFINE_LSM(smack) = { .name = "smack", - .flags = LSM_FLAG_LEGACY_MAJOR, + .flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE, .init = smack_init, };
diff --git a/security/tomoyo/tomoyo.c b/security/tomoyo/tomoyo.c
index a46f6bc1e97c..daff7d7897ad 100644
--- a/security/tomoyo/tomoyo.c
+++ b/security/tomoyo/tomoyo.c@@ -550,6 +550,6 @@ static int __init tomoyo_init(void) DEFINE_LSM(tomoyo) = { .name = "tomoyo", - .flags = LSM_FLAG_LEGACY_MAJOR, + .flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE, .init = tomoyo_init, };
--
2.17.1