Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+8865eaff7f9acd593945@syzkaller.appspotmail.com, Tom Herbert , Eric Dumazet , "David S. Miller" Subject: [PATCH 4.9 003/145] kcm: Only allow TCP sockets to be attached to a KCM mux Date: Fri, 23 Feb 2018 19:25:09 +0100 Message-Id: <20180223170725.169691035@linuxfoundation.org> In-Reply-To: <20180223170724.669759283@linuxfoundation.org> References: <20180223170724.669759283@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tom Herbert commit 581e7226a5d43f629eb6399a121f85f6a15f81be upstream. TCP sockets for IPv4 and IPv6 that are not listeners or in closed stated are allowed to be attached to a KCM mux. Fixes: ab7ac4eb9832 ("kcm: Kernel Connection Multiplexor module") Reported-by: syzbot+8865eaff7f9acd593945@syzkaller.appspotmail.com Signed-off-by: Tom Herbert Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/kcm/kcmsock.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/net/kcm/kcmsock.c +++ b/net/kcm/kcmsock.c @@ -1381,8 +1381,13 @@ static int kcm_attach(struct socket *soc if (!csk) return -EINVAL; - /* We must prevent loops or risk deadlock ! */ - if (csk->sk_family == PF_KCM) + /* Only allow TCP sockets to be attached for now */ + if ((csk->sk_family != AF_INET && csk->sk_family != AF_INET6) || + csk->sk_protocol != IPPROTO_TCP) + return -EOPNOTSUPP; + + /* Don't allow listeners or closed sockets */ + if (csk->sk_state == TCP_LISTEN || csk->sk_state == TCP_CLOSE) return -EOPNOTSUPP; psock = kmem_cache_zalloc(kcm_psockp, GFP_KERNEL);