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authorKees Cook <keescook@chromium.org>2018-09-19 19:57:06 -0700
committerKees Cook <keescook@chromium.org>2019-01-08 13:18:43 -0800
commit14bd99c821f7ace0e8110a1bfdfaa27e1788e20f (patch)
treea5feee1ff6b832eaffef89d1bde995e0574723e2
parent7e611486d905f435faf80969deed68a615019e6b (diff)
downloadlinux-14bd99c821f7ace0e8110a1bfdfaa27e1788e20f.tar.gz
LSM: Separate idea of "major" LSM from "exclusive" LSM
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 <keescook@chromium.org> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
-rw-r--r--include/linux/lsm_hooks.h1
-rw-r--r--security/apparmor/lsm.c2
-rw-r--r--security/security.c12
-rw-r--r--security/selinux/hooks.c2
-rw-r--r--security/smack/smack_lsm.c2
-rw-r--r--security/tomoyo/tomoyo.c2
6 files changed, 17 insertions, 4 deletions
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index e28a3aa639e8..c3843b33da9e 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -2043,6 +2043,7 @@ 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)
struct lsm_info {
const char *name; /* Required. */
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index dfc5fbf8ba82..149a3e16b5da 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -1723,7 +1723,7 @@ alloc_out:
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 88de6b073246..a8dd7defe30a 100644
--- a/security/security.c
+++ b/security/security.c
@@ -49,6 +49,7 @@ static __initconst const char * const builtin_lsm_order = CONFIG_LSM;
/* 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(...) \
@@ -129,6 +130,12 @@ 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;
}
@@ -144,6 +151,11 @@ 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 chosen: %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 0f8ae2fbd14a..49865f119b16 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6989,7 +6989,7 @@ 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 580e9d6e5680..780733341d02 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -4809,6 +4809,6 @@ 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,
};