From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D21CC433E0 for ; Sun, 21 Jun 2020 12:28:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 10142248C7 for ; Sun, 21 Jun 2020 12:28:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="UBjLWd6D" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729982AbgFUM2M (ORCPT ); Sun, 21 Jun 2020 08:28:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42964 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729965AbgFUM2M (ORCPT ); Sun, 21 Jun 2020 08:28:12 -0400 Received: from mail-pf1-x442.google.com (mail-pf1-x442.google.com [IPv6:2607:f8b0:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E0CABC061794 for ; Sun, 21 Jun 2020 05:28:11 -0700 (PDT) Received: by mail-pf1-x442.google.com with SMTP id x22so7018941pfn.3 for ; Sun, 21 Jun 2020 05:28:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=MZnDktK31XZ3cHCzYWTCqoYe8polQyugNedOJdBTNaI=; b=UBjLWd6D2Zxlqm/uyDALlDaq4025v6NkAiPlfzWihWyZWZbNISmxq/bmxck+oWZeGn VwE1tAYoWO9i7CxOOaD2kOPTMNEzWyMavLNtKG3wuXM/JomTg3wFalGhS/E5ASLqLE4+ /Zg8cQ+m7vUN3qhwFYa3exLgA8KYMs0g9ZGSIM38kagshUYYovvoUpSKE3975TdsCPwr 0boDsANFci0wTOOhVCjMyZvfnqDUvYJN1lkykAT1syP4qH7TwjER5xxSdc+5CoI5vzPq Zoh5wcdZkw2srYi1gfZTmmnARja1eNH3AdF1r8x3q93YvbFSQJP6QHvvDGgxtHZC9uk9 Rf7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=MZnDktK31XZ3cHCzYWTCqoYe8polQyugNedOJdBTNaI=; b=KbC6xwSTzhRi75x0ZsZpZqDyoftsantHBZCnMXVcg1WqUvAvq3BokROarn00C1+B42 tmgicclFPlBgCnH8wQ3V8dCtE5PxC942w0v3nz0zjgWPbVFA6KHu78cacg7w2jf77QwM RumNxXfZt1/UogFwl0Pa8xgAYA1qeIFu2NRGG4Co/cNpBN6fYoO6cFUtDgdChAgMcBEA VErKZAmK9TF6+GG/AvvNpSmDHQCwGC3Mv9OWFz1Pehgwd1xpC/gslK9s/vXdBTWn0f5o p+MVWNzwijhwtivGJ9kpYg0A/H7f2+rKe+u0wxp7Q9MTrt4TKVHROiI53p2GkNTe1xsq BuDw== X-Gm-Message-State: AOAM531NjxC0MH6JQ54OhbUvew2o33NPEvj5lfhyUDVZNwVtmUtkxFXl oyGAouMAGeI1HrZ6z6zjILbrcJQS2Vc= X-Google-Smtp-Source: ABdhPJwjjsJlBmH3KwjMYrCE8gczslmGlcxsI4PfQd4tenx4mbX5veUpCpgaWCxHQmxrVqCuKXuKmw== X-Received: by 2002:a65:4807:: with SMTP id h7mr9470906pgs.123.1592742490769; Sun, 21 Jun 2020 05:28:10 -0700 (PDT) Received: from ubuntu.localdomain ([220.116.27.194]) by smtp.gmail.com with ESMTPSA id u128sm10940107pfu.148.2020.06.21.05.28.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 21 Jun 2020 05:28:10 -0700 (PDT) From: youngjun To: Miklos Szeredi Cc: linux-unionfs@vger.kernel.org, youngjun Subject: [PATCH] ovl: null dereference possibility fixup Date: Sun, 21 Jun 2020 05:27:47 -0700 Message-Id: <20200621122747.58787-1-her0gyugyu@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: linux-unionfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-unionfs@vger.kernel.org lowerdentry could be NULL, and dereferenced by calling d_inode. code flow which described below shows possibility of null dereference in ovl_get_inode. (export.c) ovl_lower_fh_to_d |_(export.c) ovl_get_dentry(sb, upper, NULL, NULL); |_(export.c) ovl_obtain_alias (sb, upper, NULL, NULL); |_(inode.c) ovl_get_inode(sb, &oip); |_(in ovl_get_inode) realinode = d_inode(lowerdentry); Fixes: 09d8b586731bf("ovl: move __upperdentry to ovl_inode") Signed-off-by: youngjun --- fs/overlayfs/inode.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 8be6cd264f66..53d82ef68ba8 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -958,8 +958,10 @@ struct inode *ovl_get_inode(struct super_block *sb, unsigned long ino = 0; int err = oip->newinode ? -EEXIST : -ENOMEM; - if (!realinode) + if (!realinode && lowerdentry) realinode = d_inode(lowerdentry); + else + return ERR_PTR(-EINVAL); /* * Copy up origin (lower) may exist for non-indexed upper, but we must -- 2.17.1