From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Liping Zhang <zlpnobody@163.com>
Cc: netfilter-devel@vger.kernel.org, cernekee@chromium.org,
fgao@ikuai8.com, Liping Zhang <zlpnobody@gmail.com>
Subject: Re: [PATCH nf V2] netfilter: ctnetlink: make it safer when updating ct->status
Date: Fri, 14 Apr 2017 01:25:55 +0200 [thread overview]
Message-ID: <20170413232555.GA7517@salvia> (raw)
In-Reply-To: <1492088027-10389-1-git-send-email-zlpnobody@163.com>
On Thu, Apr 13, 2017 at 08:53:47PM +0800, Liping Zhang wrote:
> From: Liping Zhang <zlpnobody@gmail.com>
>
> User can update the ct->status via nfnetlink, but using a non-atomic
> operation "ct->status |= status;". This is unsafe, and may clear
> IPS_DYING_BIT bit set by another CPU unexpectedly. For example:
> CPU0 CPU1
> ctnetlink_change_status __nf_conntrack_find_get
> old = ct->status nf_ct_gc_expired
> - nf_ct_kill
> - test_and_set_bit(IPS_DYING_BIT
> new = old | status; -
> ct->status = new; <-- oops, _DYING_ is cleared!
This is fixing an issue that was introduced in ca7433df3a67.
So I would like this comes in a patch batch including the several
patches that we need to fix the conntrack update path from ctnetlink.
next prev parent reply other threads:[~2017-04-13 23:26 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-13 12:53 [PATCH nf V2] netfilter: ctnetlink: make it safer when updating ct->status Liping Zhang
2017-04-13 23:25 ` Pablo Neira Ayuso [this message]
2017-04-14 2:43 ` Liping Zhang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170413232555.GA7517@salvia \
--to=pablo@netfilter.org \
--cc=cernekee@chromium.org \
--cc=fgao@ikuai8.com \
--cc=netfilter-devel@vger.kernel.org \
--cc=zlpnobody@163.com \
--cc=zlpnobody@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).