From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-97.freemail.mail.aliyun.com (out30-97.freemail.mail.aliyun.com [115.124.30.97]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BB50E6A022 for ; Fri, 23 Aug 2024 06:13:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.97 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724393599; cv=none; b=nU6Gbh+SERTHFx6gVM6SHcQ+p7Qlh/h6hwwLH4bW//XDBTMtChCUiQ+8PSRNRGPHbH/A9yQJxiPpDXoVVDtTHwWG2Oi5/z8o5fGVBgGA0Q9Znwu3J9kJm1Wvu24KReyjfQxVSNWmDS7EP1l0y0penILkt31x7pPRfo2LNKPKw9M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724393599; c=relaxed/simple; bh=VUMwXIMSyIeTBZlzaPoBJKVKFDfRDDHp4ZTbcK6E7D0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=IH6EPQ20mTn4QQDf7veehKVHkswyT+3jMEwj/6oIWR3fUrePcy638Q2oI88g7kPOyLMaend+s7v1A4GjmLJeUgPif8wmurInJgRWNt/9CXU/Vz5zQ0PA1IqrLX9lRgZ6+OQRk4XFR809/vBtaBECggto76ozN9axGpM0dCUu1sg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=VruIH0DG; arc=none smtp.client-ip=115.124.30.97 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="VruIH0DG" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1724393587; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=l9vVfdqNR2maj7WJKOY1sDy7gPIzSYM4Hjrqvr3z5nc=; b=VruIH0DGPo5q2NSd50cocj/uodlyZXw44pgxGoolIfBH5WOXslUa1OVKlf2/QlRBUHL46vgZuSt4wK5BhbZgo/rFwxv5n+NPt6khjaxp0zwfSKU1ZUNRxUIIDIUJJX6vR03+sjnotcjS+fLXvXju/btwZGCoGK+rPb8HRU9hoc0= Received: from 30.221.129.19(mailfrom:joseph.qi@linux.alibaba.com fp:SMTPD_---0WDSR2PV_1724393586) by smtp.aliyun-inc.com; Fri, 23 Aug 2024 14:13:07 +0800 Message-ID: Date: Fri, 23 Aug 2024 14:13:06 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] ocfs2: fix null-ptr-deref when journal load failed. To: Julian Sun Cc: ocfs2-devel@lists.linux.dev, jlbec@evilplan.org, mark@fasheh.com, syzbot+05b9b39d8bdfe1a0861f@syzkaller.appspotmail.com, "linux-kernel@vger.kernel.org" References: <20240819131120.746077-1-sunjunchao2870@gmail.com> <26da607a-530d-4dc1-9040-bf56b406b98f@linux.alibaba.com> Content-Language: en-US From: Joseph Qi In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 8/23/24 10:22 AM, Julian Sun wrote: > On Fri, 2024-08-23 at 09:59 +0800, Joseph Qi wrote: >> >> >> On 8/20/24 11:19 PM, Julian Sun wrote: >>> Joseph Qi 于2024年8月20日周二 21:03写道： >>>> >>>> >>>> >>>> On 8/19/24 9:11 PM, Julian Sun wrote: >>>>> During the mounting process, if the jbd2_journal_load() >>>>> call fails, it will internally invoke journal_reset() >>>>> ->journal_fail_superblock(), which sets journal->j_sb_buffer >>>> >>>> >>>>> This description is not right. >>>>> journal_reset() fails because of too short journal, then lead >>>>> to >>>>> jbd2_journal_load() fails with NULL j_sb_buffer. >>> yeah. That's exactly what I described. >>>> >>>>> to NULL. Subsequently, ocfs2_journal_shutdown() calls >>>>> jbd2_journal_flush()->jbd2_cleanup_journal_tail()-> >>>>> __jbd2_update_log_tail()->jbd2_journal_update_sb_log_tail() >>>>> ->lock_buffer(journal->j_sb_buffer), resulting in a >>>>> null-pointer dereference error. >>>>> >>>>> To resolve this issue, a new state OCFS2_JOURNAL_INITED >>>>> has been introduced to replace the previous functionality >>>>> of OCFS2_JOURNAL_LOADED, the original OCFS2_JOURNAL_LOADED >>>>> is only set when ocfs2_journal_load() is successful. >>>> >>>> >>>>> Or set OCFS2_JOURNAL_LOADED only after JBD2_LOADED? >>> I don't think this is correct. We first call ocfs2_journal_init(), >>> which allocates some resources, before calling jbd2_journal_load(). >>> If >>> ocfs2_journal_init() succeeds but jbd2_journal_load() fails, this >>> solution may lead to a resource leak. >>> If there is anything important I'm missing, please let me know, >>> thanks. >>> >> >> Okay, seems except iput(inode) and kfree(journal), we may have to do >> the >> following cleanup: >> 1) ocfs2_inode_unlock(journal->j_inode); >> 2) brelse(journal->j_bh); >> 3) OCFS2_I(inode)->ip_open_count-- >> 4) jbd2_journal_destroy() >> ... >> >> So it seems that introducing a new state will be more clear. >> >>>>> The jbd2_journal_flush() function is allowed to be called >>>>> only when this flag is set. The logic here is that if the >>>>> journal has even not been successfully loaded, there is >>>>> no need to flush the journal. >>>>> >>>>> Link: >>>>> https://syzkaller.appspot.com/bug?extid=05b9b39d8bdfe1a0861f >>>>> Reported-by: >>>>> syzbot+05b9b39d8bdfe1a0861f@syzkaller.appspotmail.com >>>>> Signed-off-by: Julian Sun >>>>> --- >>>>>  fs/ocfs2/journal.c | 9 ++++++--- >>>>>  fs/ocfs2/journal.h | 1 + >>>>>  2 files changed, 7 insertions(+), 3 deletions(-) >>>>> >>>>> diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c >>>>> index 530fba34f6d3..6f837296048f 100644 >>>>> --- a/fs/ocfs2/journal.c >>>>> +++ b/fs/ocfs2/journal.c >>>>> @@ -968,7 +968,7 @@ int ocfs2_journal_init(struct ocfs2_super >>>>> *osb, int *dirty) >>>>> >>>>>       ocfs2_set_journal_params(osb); >>>>> >>>>> -     journal->j_state = OCFS2_JOURNAL_LOADED; >>>>> +     journal->j_state = OCFS2_JOURNAL_INITED; >>>>> >>>>>       status = 0; >>>>>  done: >>>>> @@ -1039,6 +1039,7 @@ void ocfs2_journal_shutdown(struct >>>>> ocfs2_super *osb) >>>>>       int status = 0; >>>>>       struct inode *inode = NULL; >>>>>       int num_running_trans = 0; >>>>> +     enum ocfs2_journal_state state; >>>>> >>>>>       BUG_ON(!osb); >>>>> >>>>> @@ -1047,8 +1048,9 @@ void ocfs2_journal_shutdown(struct >>>>> ocfs2_super *osb) >>>>>               goto done; >>>>> >>>>>       inode = journal->j_inode; >>>>> +     state = journal->j_state; >>>>> >>>>> -     if (journal->j_state != OCFS2_JOURNAL_LOADED) >>>>> +     if (state != OCFS2_JOURNAL_INITED) >> >> This is not right. >> What if journal has already been loaded? > Hi, Joseph > > Thanks for your review and comments. > > I'm not sure if I fully understand what you mean. > Because the functionality of OCFS2_JOURNAL_INITED is completely > equivalent to the original OCFS2_JOURNAL_LOADED, so do you mean that > there might be an issue with the original OCFS2_JOURNAL_LOADED? If so, > I will dig it into and try to fix. > But in any case, that should be a separate patch. > > If there is any misunderstanding, please let me know, thanks. Now you separate original OCFS2_JOURNAL_LOADED into OCFS2_JOURNAL_INITED and OCFS2_JOURNAL_LOADED. And ocfs2_journal_shutdown() will be called after OCFS2_JOURNAL_LOADED is set, e.g. normal umount, or error happens after ocfs2_check_volume(). You changes break the this logic. BTW, cc linux-kernel as well. Thanks, Joseph