SELinux: Unify context mount and genfs behavior

Context mounts and genfs labeled file systems behave differently with respect to
setting file system labels. This patch brings genfs labeled file systems in line
with context mounts in that setxattr calls to them should return EOPNOTSUPP and
fscreate calls will be ignored.
Signed-off-by: David P. Quigley <dpquigl@tycho.nsa.gov>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@macbook.localdomain>

security/selinux/hooks.c

@@ -1613,7 +1613,7 @@ static int may_create(struct inode *dir,
 	if (rc)
 		return rc;
 
-	if (!newsid || sbsec->behavior == SECURITY_FS_USE_MNTPOINT) {
+	if (!newsid || !(sbsec->flags & SE_SBLABELSUPP)) {
 		rc = security_transition_sid(sid, dsec->sid, tclass, &newsid);
 		if (rc)
 			return rc;
@@ -2597,7 +2597,7 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
 	sid = tsec->sid;
 	newsid = tsec->create_sid;
 
-	if (!newsid || sbsec->behavior == SECURITY_FS_USE_MNTPOINT) {
+	if (!newsid || !(sbsec->flags & SE_SBLABELSUPP)) {
 		rc = security_transition_sid(sid, dsec->sid,
 					     inode_mode_to_security_class(inode->i_mode),
 					     &newsid);
@@ -2619,7 +2619,7 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
 		isec->initialized = 1;
 	}
 
-	if (!ss_initialized || sbsec->behavior == SECURITY_FS_USE_MNTPOINT)
+	if (!ss_initialized || !(sbsec->flags & SE_SBLABELSUPP))
 		return -EOPNOTSUPP;
 
 	if (name) {
@@ -2796,7 +2796,7 @@ static int selinux_inode_setxattr(struct dentry *dentry, const char *name,
 		return selinux_inode_setotherxattr(dentry, name);
 
 	sbsec = inode->i_sb->s_security;
-	if (sbsec->behavior == SECURITY_FS_USE_MNTPOINT)
+	if (!(sbsec->flags & SE_SBLABELSUPP))
 		return -EOPNOTSUPP;
 
 	if (!is_owner_or_cap(inode))