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From: "Michael S. Tsirkin" <mst@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org, Jason Wang <jasowang@redhat.com>,
	John Fastabend <john.fastabend@gmail.com>,
	David Miller <davem@davemloft.net>
Subject: [PATCH net-next 04/12] tap: fix use-after-free
Date: Fri, 26 Jan 2018 01:36:31 +0200	[thread overview]
Message-ID: <1516923320-16959-5-git-send-email-mst@redhat.com> (raw)
In-Reply-To: <1516923320-16959-1-git-send-email-mst@redhat.com>

Lockless access to __ptr_ring_full is only legal if ring is
never resized, otherwise it might cause use-after free errors.
Simply drop the lockless test, we'll drop the packet
a bit later when produce fails.

Fixes: 362899b8 ("macvtap: switch to use skb array")
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/net/tap.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index 7c38659..7787269 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -330,9 +330,6 @@ rx_handler_result_t tap_handle_frame(struct sk_buff **pskb)
 	if (!q)
 		return RX_HANDLER_PASS;
 
-	if (__ptr_ring_full(&q->ring))
-		goto drop;
-
 	skb_push(skb, ETH_HLEN);
 
 	/* Apply the forward feature mask so that we perform segmentation
-- 
MST

  parent reply	other threads:[~2018-01-25 23:36 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-25 23:36 [PATCH net-next 00/12] ptr_ring fixes Michael S. Tsirkin
2018-01-25 23:36 ` [PATCH net-next 01/12] ptr_ring: keep consumer_head valid at all times Michael S. Tsirkin
2018-01-26  0:11   ` John Fastabend
2018-01-25 23:36 ` [PATCH net-next 02/12] ptr_ring: clean up documentation Michael S. Tsirkin
2018-01-25 23:36 ` [PATCH net-next 03/12] ptr_ring: READ/WRITE_ONCE for __ptr_ring_empty Michael S. Tsirkin
2018-01-26  2:37   ` Jason Wang
2018-01-26  2:44     ` Michael S. Tsirkin
2018-01-26  3:19       ` Jason Wang
2018-01-26 13:44         ` Michael S. Tsirkin
2018-01-25 23:36 ` Michael S. Tsirkin [this message]
2018-01-25 23:36 ` [PATCH net-next 05/12] ptr_ring: disallow lockless __ptr_ring_full Michael S. Tsirkin
2018-01-26  2:38   ` Jason Wang
2018-01-26  2:46     ` Michael S. Tsirkin
2018-01-29  3:36       ` Jason Wang
2018-01-29  4:41         ` Michael S. Tsirkin
2018-01-29  7:09           ` Jason Wang
2018-01-25 23:36 ` [PATCH net-next 06/12] Revert "net: ptr_ring: otherwise safe empty checks can overrun array bounds" Michael S. Tsirkin
2018-01-26  0:12   ` John Fastabend
2018-01-25 23:36 ` [PATCH net-next 07/12] skb_array: use __ptr_ring_empty Michael S. Tsirkin
2018-01-25 23:36 ` [PATCH net-next 08/12] ptr_ring: prevent queue load/store tearing Michael S. Tsirkin
2018-01-26  2:38   ` Jason Wang
2018-01-26  2:49     ` Michael S. Tsirkin
2018-01-25 23:36 ` [PATCH net-next 09/12] tools/virtio: switch to __ptr_ring_empty Michael S. Tsirkin
2018-01-25 23:36 ` [PATCH net-next 10/12] tools/virtio: more stubs to fix tools build Michael S. Tsirkin
2018-01-25 23:36 ` [PATCH net-next 11/12] tools/virtio: copy READ/WRITE_ONCE Michael S. Tsirkin
2018-01-25 23:36 ` [PATCH net-next 12/12] tools/virtio: fix smp_mb on x86 Michael S. Tsirkin
2018-01-26  3:56   ` Jason Wang
2018-01-26 13:45     ` Michael S. Tsirkin
2018-01-26  3:20 ` [PATCH net-next 00/12] ptr_ring fixes Jason Wang
2018-01-29  7:10 ` Jason Wang
2018-01-29 17:03   ` David Miller

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