[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20230124173945.064f64e3@kernel.org>
Date: Tue, 24 Jan 2023 17:39:45 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: Vladimir Oltean <vladimir.oltean@....com>
Cc: netdev@...r.kernel.org, "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Paolo Abeni <pabeni@...hat.com>,
Michal Kubecek <mkubecek@...e.cz>
Subject: Re: [PATCH net-next] net: ethtool: fix NULL pointer dereference in
pause_prepare_data()
On Tue, 24 Jan 2023 13:13:28 +0200 Vladimir Oltean wrote:
> In the following call path:
>
> ethnl_default_dumpit
> -> ethnl_default_dump_one
> -> ctx->ops->prepare_data
> -> pause_prepare_data
>
> struct genl_info *info will be passed as NULL, and pause_prepare_data()
> dereferences it while getting the extended ack pointer.
>
> To avoid that, just set the extack to NULL if "info" is NULL, since the
> netlink extack handling messages know how to deal with that.
>
> The pattern "info ? info->extack : NULL" is present in quite a few other
> "prepare_data" implementations, so it's clear that it's a more general
> problem to be dealt with at a higher level, but the code should have at
> least adhered to the current conventions to avoid the NULL dereference.
>
> Fixes: 04692c9020b7 ("net: ethtool: netlink: retrieve stats from multiple sources (eMAC, pMAC)")
> Reported-by: Eric Dumazet <edumazet@...gle.com>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>
Reported-by: syzbot+9d44aae2720fc40b8474@...kaller.appspotmail.com
Powered by blists - more mailing lists