From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Benjamin Poirier , Willem de Bruijn , "David S. Miller" Subject: [PATCH 4.9 11/78] packet: Dont write vnet header beyond end of buffer Date: Mon, 18 Sep 2017 11:11:20 +0200 Message-Id: <20170918091127.800908815@linuxfoundation.org> In-Reply-To: <20170918091126.077483037@linuxfoundation.org> References: <20170918091126.077483037@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: Benjamin Poirier [ Upstream commit edbd58be15a957f6a760c4a514cd475217eb97fd ] ... which may happen with certain values of tp_reserve and maclen. Fixes: 58d19b19cd99 ("packet: vnet_hdr support for tpacket_rcv") Signed-off-by: Benjamin Poirier Cc: Willem de Bruijn Acked-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/packet/af_packet.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2151,6 +2151,7 @@ static int tpacket_rcv(struct sk_buff *s struct timespec ts; __u32 ts_status; bool is_drop_n_account = false; + bool do_vnet = false; /* struct tpacket{2,3}_hdr is aligned to a multiple of TPACKET_ALIGNMENT. * We may add members to them until current aligned size without forcing @@ -2201,8 +2202,10 @@ static int tpacket_rcv(struct sk_buff *s netoff = TPACKET_ALIGN(po->tp_hdrlen + (maclen < 16 ? 16 : maclen)) + po->tp_reserve; - if (po->has_vnet_hdr) + if (po->has_vnet_hdr) { netoff += sizeof(struct virtio_net_hdr); + do_vnet = true; + } macoff = netoff - maclen; } if (po->tp_version <= TPACKET_V2) { @@ -2219,8 +2222,10 @@ static int tpacket_rcv(struct sk_buff *s skb_set_owner_r(copy_skb, sk); } snaplen = po->rx_ring.frame_size - macoff; - if ((int)snaplen < 0) + if ((int)snaplen < 0) { snaplen = 0; + do_vnet = false; + } } } else if (unlikely(macoff + snaplen > GET_PBDQC_FROM_RB(&po->rx_ring)->max_frame_len)) { @@ -2233,6 +2238,7 @@ static int tpacket_rcv(struct sk_buff *s if (unlikely((int)snaplen < 0)) { snaplen = 0; macoff = GET_PBDQC_FROM_RB(&po->rx_ring)->max_frame_len; + do_vnet = false; } } spin_lock(&sk->sk_receive_queue.lock); @@ -2258,7 +2264,7 @@ static int tpacket_rcv(struct sk_buff *s } spin_unlock(&sk->sk_receive_queue.lock); - if (po->has_vnet_hdr) { + if (do_vnet) { if (__packet_rcv_vnet(skb, h.raw + macoff - sizeof(struct virtio_net_hdr))) { spin_lock(&sk->sk_receive_queue.lock);