diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 5aa5fe036207cb..6980ae726cc32a 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3474,10 +3474,72 @@ static int selinux_file_receive(struct file *file)
 	return file_has_perm(cred, file, file_to_av(file));
 }
 
+/*
+ * We have a file opened on a unioned file system that falls through to a file
+ * on a lower layer.  If there is a union inode, we try to get the label from
+ * that, otherwise we need to get it from the superblock.
+ *
+ * file->f_path points to the union layer and file->f_inode points to the lower
+ * layer.
+ */
+static int selinux_file_open_union(struct file *file,
+				   struct file_security_struct *fsec,
+				   const struct cred *cred)
+{
+	const struct superblock_security_struct *sbsec;
+	const struct inode_security_struct *isec, *dsec, *fisec;
+	const struct task_security_struct *tsec = current_security();
+	struct common_audit_data ad;
+	struct dentry *union_dentry = file->f_path.dentry;
+	const struct inode *union_inode = d_inode(union_dentry);
+	const struct inode *lower_inode = file_inode(file);
+	struct dentry *dir;
+	int rc;
+
+	sbsec = union_dentry->d_sb->s_security;
+
+	if (union_inode) {
+		isec = union_inode->i_security;
+		fsec->union_isid = isec->sid;
+	} else if ((sbsec->flags & SE_SBINITIALIZED) &&
+		   (sbsec->behavior == SECURITY_FS_USE_MNTPOINT)) {
+		fsec->union_isid = sbsec->mntpoint_sid;
+	} else {
+		dir = dget_parent(union_dentry);
+		dsec = d_inode(dir)->i_security;
+
+		rc = security_transition_sid(
+			tsec->sid, dsec->sid,
+			inode_mode_to_security_class(lower_inode->i_mode),
+			&union_dentry->d_name,
+			&fsec->union_isid);
+		dput(dir);
+		if (rc) {
+			pr_warn("%s:  security_transition_sid failed, rc=%d (name=%pD)\n",
+				__func__, -rc, file);
+			return rc;
+		}
+	}
+
+	/* We need to check that the union file is allowed to be opened as well
+	 * as checking that the lower file is allowed to be opened.
+	 */
+	if (unlikely(IS_PRIVATE(lower_inode)))
+		return 0;
+
+	ad.type = LSM_AUDIT_DATA_PATH;
+	ad.u.path = file->f_path;
+
+	fisec = lower_inode->i_security;
+	return avc_has_perm(cred_sid(cred), fsec->union_isid, fisec->sclass,
+			    open_file_to_av(file), &ad);
+}
+
 static int selinux_file_open(struct file *file, const struct cred *cred)
 {
 	struct file_security_struct *fsec;
 	struct inode_security_struct *isec;
+	int rc;
 
 	fsec = file->f_security;
 	isec = file_inode(file)->i_security;
@@ -3498,6 +3560,13 @@ static int selinux_file_open(struct file *file, const struct cred *cred)
 	 * new inode label or new policy.
 	 * This check is not redundant - do not remove.
 	 */
+
+	if (d_inode(file->f_path.dentry) != file->f_inode) {
+		rc = selinux_file_open_union(file, fsec, cred);
+		if (rc < 0)
+			return rc;
+	}
+
 	return file_path_has_perm(cred, file, open_file_to_av(file));
 }
 
diff --git a/security/selinux/include/objsec.h b/security/selinux/include/objsec.h
index 81fa718d5cb388..f088c080aa9e8a 100644
--- a/security/selinux/include/objsec.h
+++ b/security/selinux/include/objsec.h
@@ -54,6 +54,7 @@ struct file_security_struct {
 	u32 sid;		/* SID of open file description */
 	u32 fown_sid;		/* SID of file owner (for SIGIO) */
 	u32 isid;		/* SID of inode at the time of file open */
+	u32 union_isid;		/* SID of would-be inodes in union top (or 0) */
 	u32 pseqno;		/* Policy seqno at the time of file open */
 };