From: Guillaume Nault <gnault@redhat.com>
To: Eric Dumazet <edumazet@google.com>
Cc: "David S . Miller" <davem@davemloft.net>,
netdev <netdev@vger.kernel.org>,
Eric Dumazet <eric.dumazet@gmail.com>,
James Chapman <jchapman@katalix.com>,
syzbot <syzkaller@googlegroups.com>
Subject: Re: [PATCH net] l2tp: add sk_family checks to l2tp_validate_socket
Date: Sat, 30 May 2020 17:51:36 +0200 [thread overview]
Message-ID: <20200530155136.GA31596@pc-3.home> (raw)
In-Reply-To: <20200529183225.150288-1-edumazet@google.com>
On Fri, May 29, 2020 at 11:32:25AM -0700, Eric Dumazet wrote:
> syzbot was able to trigger a crash after using an ISDN socket
> and fool l2tp.
>
> Fix this by making sure the UDP socket is of the proper family.
>
> --- a/net/l2tp/l2tp_core.c
> +++ b/net/l2tp/l2tp_core.c
> @@ -1458,6 +1458,9 @@ static int l2tp_validate_socket(const struct sock *sk, const struct net *net,
> if (sk->sk_type != SOCK_DGRAM)
> return -EPROTONOSUPPORT;
>
> + if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6)
> + return -EPROTONOSUPPORT;
> +
> if ((encap == L2TP_ENCAPTYPE_UDP && sk->sk_protocol != IPPROTO_UDP) ||
> (encap == L2TP_ENCAPTYPE_IP && sk->sk_protocol != IPPROTO_L2TP))
> return -EPROTONOSUPPORT;
>
Thanks a lot!
Acked-by: Guillaume Nault <gnault@redhat.com>
next prev parent reply other threads:[~2020-05-30 15:51 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-29 18:32 [PATCH net] l2tp: add sk_family checks to l2tp_validate_socket Eric Dumazet
2020-05-30 15:51 ` Guillaume Nault [this message]
2020-05-31 4:57 ` David Miller
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