From: Stephen Smalley <sds@tycho.nsa.gov>
Date: Wed, 4 Sep 2019 10:32:48 -0400
Subject: selinux: fix residual uses of current_security() for the SELinux blob
Git-commit: 169ce0c081cd85f78388bb6c1638c1ad7b81bde7
Patch-mainline: 5.4-rc1
References: bnc#1151927 5.3.5

We need to use selinux_cred() to fetch the SELinux cred blob instead
of directly using current->security or current_security().  There
were a couple of lingering uses of current_security() in the SELinux code
that were apparently missed during the earlier conversions. IIUC, this
would only manifest as a bug if multiple security modules including
SELinux are enabled and SELinux is not first in the lsm order. After
this change, there appear to be no other users of current_security()
in-tree; perhaps we should remove it altogether.

Fixes: bbd3662a8348 ("Infrastructure management of the cred security blob")
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 security/selinux/hooks.c          |    2 +-
 security/selinux/include/objsec.h |   20 ++++++++++----------
 2 files changed, 11 insertions(+), 11 deletions(-)

--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3403,7 +3403,7 @@ static int selinux_inode_copy_up_xattr(c
 static int selinux_kernfs_init_security(struct kernfs_node *kn_dir,
 					struct kernfs_node *kn)
 {
-	const struct task_security_struct *tsec = current_security();
+	const struct task_security_struct *tsec = selinux_cred(current_cred());
 	u32 parent_sid, newsid, clen;
 	int rc;
 	char *context;
--- a/security/selinux/include/objsec.h
+++ b/security/selinux/include/objsec.h
@@ -37,16 +37,6 @@ struct task_security_struct {
 	u32 sockcreate_sid;	/* fscreate SID */
 };
 
-/*
- * get the subjective security ID of the current task
- */
-static inline u32 current_sid(void)
-{
-	const struct task_security_struct *tsec = current_security();
-
-	return tsec->sid;
-}
-
 enum label_initialized {
 	LABEL_INVALID,		/* invalid or not initialized */
 	LABEL_INITIALIZED,	/* initialized */
@@ -185,4 +175,14 @@ static inline struct ipc_security_struct
 	return ipc->security + selinux_blob_sizes.lbs_ipc;
 }
 
+/*
+ * get the subjective security ID of the current task
+ */
+static inline u32 current_sid(void)
+{
+	const struct task_security_struct *tsec = selinux_cred(current_cred());
+
+	return tsec->sid;
+}
+
 #endif /* _SELINUX_OBJSEC_H_ */