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Patch "packet: Don't write vnet header beyond end of buffer" has been added to the 4.9-stable tree

PATCH [email protected] 1 participant 1 message Sep 15, 2017

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This is a note to let you know that I've just added the patch titled

packet: Don't write vnet header beyond end of buffer

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
packet-don-t-write-vnet-header-beyond-end-of-buffer.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From foo@baz Thu Sep 14 23:20:08 PDT 2017

From: Benjamin Poirier <[email protected]>
Date: Mon, 28 Aug 2017 14:29:41 -0400
Subject: packet: Don't write vnet header beyond end of buffer

From: Benjamin Poirier <[email protected]>

[ 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 <[email protected]>
Cc Willem de Bruijn <[email protected]>
Acked-by Willem de Bruijn <[email protected]>
Signed-off-by David S. Miller <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 net/packet/af_packet.c |   12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)
net/packet/af_packet.c +9 -3
@@ -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);

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/packet-don-t-write-vnet-header-beyond-end-of-buffer.patch