From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Dongli Zhang <dongli.zhang@oracle.com>,
"David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.3 08/21] xen-netfront: do not assume sk_buff_head list is empty in error handling
Date: Fri, 20 Sep 2019 00:03:09 +0200 [thread overview]
Message-ID: <20190919214702.452008775@linuxfoundation.org> (raw)
In-Reply-To: <20190919214657.842130855@linuxfoundation.org>
From: Dongli Zhang <dongli.zhang@oracle.com>
[ Upstream commit 00b368502d18f790ab715e055869fd4bb7484a9b ]
When skb_shinfo(skb) is not able to cache extra fragment (that is,
skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS), xennet_fill_frags() assumes
the sk_buff_head list is already empty. As a result, cons is increased only
by 1 and returns to error handling path in xennet_poll().
However, if the sk_buff_head list is not empty, queue->rx.rsp_cons may be
set incorrectly. That is, queue->rx.rsp_cons would point to the rx ring
buffer entries whose queue->rx_skbs[i] and queue->grant_rx_ref[i] are
already cleared to NULL. This leads to NULL pointer access in the next
iteration to process rx ring buffer entries.
Below is how xennet_poll() does error handling. All remaining entries in
tmpq are accounted to queue->rx.rsp_cons without assuming how many
outstanding skbs are remained in the list.
985 static int xennet_poll(struct napi_struct *napi, int budget)
... ...
1032 if (unlikely(xennet_set_skb_gso(skb, gso))) {
1033 __skb_queue_head(&tmpq, skb);
1034 queue->rx.rsp_cons += skb_queue_len(&tmpq);
1035 goto err;
1036 }
It is better to always have the error handling in the same way.
Fixes: ad4f15dc2c70 ("xen/netfront: don't bug in case of too many frags")
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/xen-netfront.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -906,7 +906,7 @@ static RING_IDX xennet_fill_frags(struct
__pskb_pull_tail(skb, pull_to - skb_headlen(skb));
}
if (unlikely(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) {
- queue->rx.rsp_cons = ++cons;
+ queue->rx.rsp_cons = ++cons + skb_queue_len(list);
kfree_skb(nskb);
return ~0U;
}
next prev parent reply other threads:[~2019-09-19 22:36 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-19 22:03 [PATCH 5.3 00/21] 5.3.1-stable review Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 01/21] USB: usbcore: Fix slab-out-of-bounds bug during device reset Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 02/21] media: tm6000: double free if usb disconnect while streaming Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 03/21] phy: renesas: rcar-gen3-usb2: Disable clearing VBUS in over-current Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 04/21] ip6_gre: fix a dst leak in ip6erspan_tunnel_xmit Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 05/21] net/sched: fix race between deactivation and dequeue for NOLOCK qdisc Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 06/21] net_sched: let qdisc_put() accept NULL pointer Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 07/21] udp: correct reuseport selection with connected sockets Greg Kroah-Hartman
2019-09-19 22:03 ` Greg Kroah-Hartman [this message]
2019-09-19 22:03 ` [PATCH 5.3 09/21] net: dsa: Fix load order between DSA drivers and taggers Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 10/21] net: stmmac: Hold rtnl lock in suspend/resume callbacks Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 11/21] KVM: coalesced_mmio: add bounds checking Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 12/21] Documentation: sphinx: Add missing comma to list of strings Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 13/21] firmware: google: check if size is valid when decoding VPD data Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 14/21] serial: sprd: correct the wrong sequence of arguments Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 15/21] tty/serial: atmel: reschedule TX after RX was started Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 16/21] nl80211: Fix possible Spectre-v1 for CQM RSSI thresholds Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 17/21] Revert "arm64: Remove unnecessary ISBs from set_{pte,pmd,pud}" Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 18/21] ovl: fix regression caused by overlapping layers detection Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 19/21] phy: qcom-qmp: Correct ready status, again Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 20/21] floppy: fix usercopy direction Greg Kroah-Hartman
2019-09-19 22:03 ` [PATCH 5.3 21/21] media: technisat-usb2: break out of loop at end of buffer Greg Kroah-Hartman
2019-09-20 13:45 ` [PATCH 5.3 00/21] 5.3.1-stable review Guenter Roeck
2019-09-20 13:54 ` Jon Hunter
2019-09-20 14:24 ` Greg Kroah-Hartman
2019-09-20 16:01 ` Jon Hunter
2019-09-22 8:13 ` Greg Kroah-Hartman
2019-09-20 14:41 ` Naresh Kamboju
2019-09-21 5:06 ` Greg Kroah-Hartman
2019-09-20 21:17 ` shuah
2019-09-21 5:04 ` Greg Kroah-Hartman
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