From: David Ahern <dsahern@gmail.com>
To: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>,
netdev@vger.kernel.org
Cc: roopa@cumulusnetworks.com
Subject: Re: [PATCH net 1/2] net: nexthop: dereference nh only once in nexthop_select_path
Date: Tue, 19 May 2020 09:51:34 -0600 [thread overview]
Message-ID: <54c02cfa-00be-1379-1965-5ab833d3d5b1@gmail.com> (raw)
In-Reply-To: <20200519110424.2397623-2-nikolay@cumulusnetworks.com>
On 5/19/20 5:04 AM, Nikolay Aleksandrov wrote:
> the ->nh pointer might become suddenly null while we're selecting the
> path and we may dereference it. Dereference it only once in the
> beginning and use that if it's not null, we rely on the refcounting and
> rcu to protect against use-after-free.
the num_nh is also affected. I think an rcu update of the entire nh_grp
is the better solution. Dataplane should always see a valid nh_grp via rcu.
next prev parent reply other threads:[~2020-05-19 15:51 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-19 11:04 [PATCH net 0/2] net: nexthop: multipath null ptr deref fixes Nikolay Aleksandrov
2020-05-19 11:04 ` [PATCH net 1/2] net: nexthop: dereference nh only once in nexthop_select_path Nikolay Aleksandrov
2020-05-19 15:51 ` David Ahern [this message]
2020-05-19 11:04 ` [PATCH net 2/2] net: nexthop: check for null return by nexthop_select_path() Nikolay Aleksandrov
2020-05-19 16:11 ` [PATCH net 0/2] net: nexthop: multipath null ptr deref fixes David Ahern
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