LSM: Infrastructure management of the task security

Move management of the task_struct->security blob out
of the individual security modules and into the security
infrastructure. Instead of allocating the blobs from within
the modules the modules tell the infrastructure how much
space is required, and the space is allocated there.
The only user of this blob is AppArmor. The AppArmor use
is abstracted to avoid future conflict.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
[kees: adjusted for ordered init series]
Signed-off-by: Kees Cook <keescook@chromium.org>

1 files changed, 3 insertions, 12 deletions

diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 6821187b06ad..60ef71268ccf 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -94,19 +94,14 @@ static void apparmor_task_free(struct task_struct *task)
 {
 
 	aa_free_task_ctx(task_ctx(task));
-	task_ctx(task) = NULL;
 }
 
 static int apparmor_task_alloc(struct task_struct *task,
 			       unsigned long clone_flags)
 {
-	struct aa_task_ctx *new = aa_alloc_task_ctx(GFP_KERNEL);
-
-	if (!new)
-		return -ENOMEM;
+	struct aa_task_ctx *new = task_ctx(task);
 
 	aa_dup_task_ctx(new, task_ctx(current));
-	task_ctx(task) = new;
 
 	return 0;
 }
@@ -1157,6 +1152,7 @@ static int apparmor_inet_conn_request(struct sock *sk, struct sk_buff *skb,
 struct lsm_blob_sizes apparmor_blob_sizes __lsm_ro_after_init = {
 	.lbs_cred = sizeof(struct aa_task_ctx *),
 	.lbs_file = sizeof(struct aa_file_ctx),
+	.lbs_task = sizeof(struct aa_task_ctx),
 };
 
 static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
@@ -1487,15 +1483,10 @@ static int param_set_mode(const char *val, const struct kernel_param *kp)
 static int __init set_init_ctx(void)
 {
 	struct cred *cred = (struct cred *)current->real_cred;
-	struct aa_task_ctx *ctx;
-
-	ctx = aa_alloc_task_ctx(GFP_KERNEL);
-	if (!ctx)
-		return -ENOMEM;
 
 	lsm_early_cred(cred);
+	lsm_early_task(current);
 	set_cred_label(cred, aa_get_label(ns_unconfined(root_ns)));
-	task_ctx(current) = ctx;
 
 	return 0;
 }