netdev - Re: [PATCH net] l2tp: do not use inet_hash()/inet

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 for Android: free password hash cracker in your pocket

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

Date:   Fri, 29 May 2020 11:12:11 -0700
From:   Eric Dumazet <edumazet@...gle.com>
To:     "David S . Miller" <davem@...emloft.net>
Cc:     netdev <netdev@...r.kernel.org>,
        Eric Dumazet <eric.dumazet@...il.com>,
        James Chapman <jchapman@...alix.com>,
        Andrii Nakryiko <andriin@...com>,
        syzbot+3610d489778b57cc8031@...kaller.appspotmail.com
Subject: Re: [PATCH net] l2tp: do not use inet_hash()/inet_unhash()

On Fri, May 29, 2020 at 11:08 AM Eric Dumazet <edumazet@...gle.com> wrote:
>
> syzbot recently found a way to crash the kernel [1]
>
> Issue here is that inet_hash() & inet_unhash() are currently
> only meant to be used by TCP & DCCP, since only these protocols
> provide the needed hashinfo pointer.
>
> L2TP uses a single list (instead of a hash table)
>
> This old bug became an issue after commit 610236587600
> ("bpf: Add new cgroup attach type to enable sock modifications")
> since after this commit, sk_common_release() can be called
> while the L2TP socket is still considered 'hashed'.
>

> Fixes: 0d76751fad77 ("l2tp: Add L2TPv3 IP encapsulation (no UDP) support")
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>
> Cc: James Chapman <jchapman@...alix.com>
> Cc: Andrii Nakryiko <andriin@...com>
> Reported-by: syzbot+3610d489778b57cc8031@...kaller.appspotmail.com
> ---
>

Will send a V2, I missed that ip and ipv6 modules were using a different rwlock.