lsm: replace the name field with a pointer to the lsm_id struct

Reduce the duplication between the lsm_id struct and the DEFINE_LSM()
definition by linking the lsm_id struct directly into the individual
LSM's DEFINE_LSM() instance.

Linking the lsm_id into the LSM definition also allows us to simplify
the security_add_hooks() function by removing the code which populates
the lsm_idlist[] array and moving it into the normal LSM startup code
where the LSM list is parsed and the individual LSMs are enabled,
making for a cleaner implementation with less overhead at boot.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

Author: pcmoore

include/linux/lsm_hooks.h

@@ -152,7 +152,7 @@ enum lsm_order {
 };
 
 struct lsm_info {
-	const char *name;	/* Required. */
+	const struct lsm_id *id;
 	enum lsm_order order;	/* Optional: default is LSM_ORDER_MUTABLE */
 	unsigned long flags;	/* Optional: flags describing LSM */
 	int *enabled;		/* Optional: controlled by CONFIG_LSM */

security/apparmor/lsm.c

@@ -2555,7 +2555,7 @@ static int __init apparmor_init(void)
 }
 
 DEFINE_LSM(apparmor) = {
-	.name = "apparmor",
+	.id = &apparmor_lsmid,
 	.flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE,
 	.enabled = &apparmor_enabled,
 	.blobs = &apparmor_blob_sizes,

security/bpf/hooks.c

@@ -33,7 +33,7 @@ struct lsm_blob_sizes bpf_lsm_blob_sizes __ro_after_init = {
 };
 
 DEFINE_LSM(bpf) = {
-	.name = "bpf",
+	.id = &bpf_lsmid,
 	.init = bpf_lsm_init,
 	.blobs = &bpf_lsm_blob_sizes
 };

security/commoncap.c

@@ -1505,7 +1505,7 @@ static int __init capability_init(void)
 }
 
 DEFINE_LSM(capability) = {
-	.name = "capability",
+	.id = &capability_lsmid,
 	.order = LSM_ORDER_FIRST,
 	.init = capability_init,
 };

security/integrity/evm/evm_main.c

@@ -1175,7 +1175,7 @@ struct lsm_blob_sizes evm_blob_sizes __ro_after_init = {
 };
 
 DEFINE_LSM(evm) = {
-	.name = "evm",
+	.id = &evm_lsmid,
 	.init = init_evm_lsm,
 	.order = LSM_ORDER_LAST,
 	.blobs = &evm_blob_sizes,

security/integrity/ima/ima_main.c

@@ -1279,7 +1279,7 @@ struct lsm_blob_sizes ima_blob_sizes __ro_after_init = {
 };
 
 DEFINE_LSM(ima) = {
-	.name = "ima",
+	.id = &ima_lsmid,
 	.init = init_ima_lsm,
 	.order = LSM_ORDER_LAST,
 	.blobs = &ima_blob_sizes,

security/ipe/ipe.c

@@ -92,7 +92,7 @@ static int __init ipe_init(void)
 }
 
 DEFINE_LSM(ipe) = {
-	.name = "ipe",
+	.id = &ipe_lsmid,
 	.init = ipe_init,
 	.blobs = &ipe_blobs,
 };

security/landlock/setup.c

@@ -75,7 +75,7 @@ static int __init landlock_init(void)
 }
 
 DEFINE_LSM(LANDLOCK_NAME) = {
-	.name = LANDLOCK_NAME,
+	.id = &landlock_lsmid,
 	.init = landlock_init,
 	.blobs = &landlock_blob_sizes,
 };

security/loadpin/loadpin.c

@@ -271,7 +271,7 @@ static int __init loadpin_init(void)
 }
 
 DEFINE_LSM(loadpin) = {
-	.name = "loadpin",
+	.id = &loadpin_lsmid,
 	.init = loadpin_init,
 };
 

security/lockdown/lockdown.c

@@ -168,6 +168,6 @@ DEFINE_EARLY_LSM(lockdown) = {
 #else
 DEFINE_LSM(lockdown) = {
 #endif
-	.name = "lockdown",
+	.id = &lockdown_lsmid,
 	.init = lockdown_lsm_init,
 };