netdev - Re: [PATCH net] ip6_gre: fix use-after-free in ip6gre_tunnel

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200615.181701.1458193855639723291.davem@davemloft.net>
Date:   Mon, 15 Jun 2020 18:17:01 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     ap420073@...il.com
Cc:     kuba@...nel.org, netdev@...r.kernel.org, xeb@...l.ru
Subject: Re: [PATCH net] ip6_gre: fix use-after-free in
 ip6gre_tunnel_lookup()

From: Taehee Yoo <ap420073@...il.com>
Date: Mon, 15 Jun 2020 15:07:51 +0000

> In the datapath, the ip6gre_tunnel_lookup() is used and it internally uses
> fallback tunnel device pointer, which is fb_tunnel_dev.
> This pointer is protected by RTNL. It's not enough to be used
> in the datapath.
> So, this pointer would be used after an interface is deleted.
> It eventually results in the use-after-free problem.
> 
> In order to avoid the problem, the new tunnel pointer variable is added,
> which indicates a fallback tunnel device's tunnel pointer.
> This is protected by both RTNL and RCU.
> So, it's safe to be used in the datapath.
 ...

I'm marking this changes requested because it seems like the feedback Eric
Dumazet provided for the ip_tunnel version of this fix applies here too.

Thank you.