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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_SANE_1 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 7D828C7618F for ; Sat, 27 Jul 2019 00:50:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 50DF522BF5 for ; Sat, 27 Jul 2019 00:50:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728473AbfG0AuC (ORCPT ); Fri, 26 Jul 2019 20:50:02 -0400 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:55968 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726115AbfG0AuC (ORCPT ); Fri, 26 Jul 2019 20:50:02 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R121e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=joseph.qi@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0TXsT3L6_1564188597; Received: from JosephdeMacBook-Pro.local(mailfrom:joseph.qi@linux.alibaba.com fp:SMTPD_---0TXsT3L6_1564188597) by smtp.aliyun-inc.com(127.0.0.1); Sat, 27 Jul 2019 08:49:58 +0800 Subject: Re: [PATCH 1/3 v2] fs: ocfs2: Fix possible null-pointer dereferences in ocfs2_xa_prepare_entry() To: Jia-Ju Bai , mark@fasheh.com, jlbec@evilplan.org, Andrew Morton Cc: ocfs2-devel@oss.oracle.com, linux-kernel@vger.kernel.org References: <20190726101447.9153-1-baijiaju1990@gmail.com> From: Joseph Qi Message-ID: Date: Sat, 27 Jul 2019 08:49:57 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190726101447.9153-1-baijiaju1990@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19/7/26 18:14, Jia-Ju Bai wrote: > In ocfs2_xa_prepare_entry(), there is an if statement on line 2136 to > check whether loc->xl_entry is NULL: > if (loc->xl_entry) > > When loc->xl_entry is NULL, it is used on line 2158: > ocfs2_xa_add_entry(loc, name_hash); > loc->xl_entry->xe_name_hash = cpu_to_le32(name_hash); > loc->xl_entry->xe_name_offset = cpu_to_le16(loc->xl_size); > and line 2164: > ocfs2_xa_add_namevalue(loc, xi); > loc->xl_entry->xe_value_size = cpu_to_le64(xi->xi_value_len); > loc->xl_entry->xe_name_len = xi->xi_name_len; > > Thus, possible null-pointer dereferences may occur. > > To fix these bugs, if loc-xl_entry is NULL, ocfs2_xa_prepare_entry() > abnormally returns with -EINVAL. > > These bugs are found by a static analysis tool STCheck written by us. > > Signed-off-by: Jia-Ju Bai Reviewed-by: Joseph Qi > --- > v2: > * Directly return -EINVAL if loc-xl_entry is NULL. > Thank Joseph for helpful advice. > > --- > fs/ocfs2/xattr.c | 44 +++++++++++++++++++++++--------------------- > 1 file changed, 23 insertions(+), 21 deletions(-) > > diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c > index 385f3aaa2448..4b876c82a35c 100644 > --- a/fs/ocfs2/xattr.c > +++ b/fs/ocfs2/xattr.c > @@ -2133,29 +2133,31 @@ static int ocfs2_xa_prepare_entry(struct ocfs2_xa_loc *loc, > if (rc) > goto out; > > - if (loc->xl_entry) { > - if (ocfs2_xa_can_reuse_entry(loc, xi)) { > - orig_value_size = loc->xl_entry->xe_value_size; > - rc = ocfs2_xa_reuse_entry(loc, xi, ctxt); > - if (rc) > - goto out; > - goto alloc_value; > - } > + if (!loc->xl_entry) { > + rc = -EINVAL; > + goto out; > + } > > - if (!ocfs2_xattr_is_local(loc->xl_entry)) { > - orig_clusters = ocfs2_xa_value_clusters(loc); > - rc = ocfs2_xa_value_truncate(loc, 0, ctxt); > - if (rc) { > - mlog_errno(rc); > - ocfs2_xa_cleanup_value_truncate(loc, > - "overwriting", > - orig_clusters); > - goto out; > - } > + if (ocfs2_xa_can_reuse_entry(loc, xi)) { > + orig_value_size = loc->xl_entry->xe_value_size; > + rc = ocfs2_xa_reuse_entry(loc, xi, ctxt); > + if (rc) > + goto out; > + goto alloc_value; > + } > + > + if (!ocfs2_xattr_is_local(loc->xl_entry)) { > + orig_clusters = ocfs2_xa_value_clusters(loc); > + rc = ocfs2_xa_value_truncate(loc, 0, ctxt); > + if (rc) { > + mlog_errno(rc); > + ocfs2_xa_cleanup_value_truncate(loc, > + "overwriting", > + orig_clusters); > + goto out; > } > - ocfs2_xa_wipe_namevalue(loc); > - } else > - ocfs2_xa_add_entry(loc, name_hash); > + } > + ocfs2_xa_wipe_namevalue(loc); > > /* > * If we get here, we have a blank entry. Fill it. We grow our >