* [PATCHv2] vhost-net: fix use-after-free in vhost_net_flush
@ 2013-06-25 14:29 Michael S. Tsirkin
2013-06-26 0:12 ` David Miller
2013-07-03 6:55 ` Michele Baldessari
0 siblings, 2 replies; 3+ messages in thread
From: Michael S. Tsirkin @ 2013-06-25 14:29 UTC (permalink / raw)
To: linux-kernel
Cc: David S. Miller, Asias He, Jason Wang, kvm, virtualization, netdev
vhost_net_ubuf_put_and_wait has a confusing name:
it will actually also free it's argument.
Thus since commit 1280c27f8e29acf4af2da914e80ec27c3dbd5c01
"vhost-net: flush outstanding DMAs on memory change"
vhost_net_flush tries to use the argument after passing it
to vhost_net_ubuf_put_and_wait, this results
in use after free.
To fix, don't free the argument in vhost_net_ubuf_put_and_wait,
add an new API for callers that want to free ubufs.
Acked-by: Asias He <asias@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
Please review, and queue for 3.10 and stable.
Changes since v1:
- no functional change, tweaked the commit message
drivers/vhost/net.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 5c77d6a..534adb0 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -149,6 +149,11 @@ static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs)
{
kref_put(&ubufs->kref, vhost_net_zerocopy_done_signal);
wait_event(ubufs->wait, !atomic_read(&ubufs->kref.refcount));
+}
+
+static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs)
+{
+ vhost_net_ubuf_put_and_wait(ubufs);
kfree(ubufs);
}
@@ -1073,7 +1078,7 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
mutex_unlock(&vq->mutex);
if (oldubufs) {
- vhost_net_ubuf_put_and_wait(oldubufs);
+ vhost_net_ubuf_put_wait_and_free(oldubufs);
mutex_lock(&vq->mutex);
vhost_zerocopy_signal_used(n, vq);
mutex_unlock(&vq->mutex);
@@ -1091,7 +1096,7 @@ err_used:
vq->private_data = oldsock;
vhost_net_enable_vq(n, vq);
if (ubufs)
- vhost_net_ubuf_put_and_wait(ubufs);
+ vhost_net_ubuf_put_wait_and_free(ubufs);
err_ubufs:
fput(sock->file);
err_vq:
--
MST
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCHv2] vhost-net: fix use-after-free in vhost_net_flush
2013-06-25 14:29 [PATCHv2] vhost-net: fix use-after-free in vhost_net_flush Michael S. Tsirkin
@ 2013-06-26 0:12 ` David Miller
2013-07-03 6:55 ` Michele Baldessari
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2013-06-26 0:12 UTC (permalink / raw)
To: mst; +Cc: linux-kernel, asias, jasowang, kvm, virtualization, netdev
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Tue, 25 Jun 2013 17:29:46 +0300
> vhost_net_ubuf_put_and_wait has a confusing name:
> it will actually also free it's argument.
> Thus since commit 1280c27f8e29acf4af2da914e80ec27c3dbd5c01
> "vhost-net: flush outstanding DMAs on memory change"
> vhost_net_flush tries to use the argument after passing it
> to vhost_net_ubuf_put_and_wait, this results
> in use after free.
> To fix, don't free the argument in vhost_net_ubuf_put_and_wait,
> add an new API for callers that want to free ubufs.
>
> Acked-by: Asias He <asias@redhat.com>
> Acked-by: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This doesn't apply cleanly to the 'net' tree, please fix this up
and resubmit.
Thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCHv2] vhost-net: fix use-after-free in vhost_net_flush
2013-06-25 14:29 [PATCHv2] vhost-net: fix use-after-free in vhost_net_flush Michael S. Tsirkin
2013-06-26 0:12 ` David Miller
@ 2013-07-03 6:55 ` Michele Baldessari
1 sibling, 0 replies; 3+ messages in thread
From: Michele Baldessari @ 2013-07-03 6:55 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: linux-kernel, David S. Miller, Asias He, Jason Wang, kvm,
virtualization, netdev
On Tue, Jun 25, 2013 at 05:29:46PM +0300, Michael S. Tsirkin wrote:
> vhost_net_ubuf_put_and_wait has a confusing name:
> it will actually also free it's argument.
> Thus since commit 1280c27f8e29acf4af2da914e80ec27c3dbd5c01
> "vhost-net: flush outstanding DMAs on memory change"
> vhost_net_flush tries to use the argument after passing it
> to vhost_net_ubuf_put_and_wait, this results
> in use after free.
> To fix, don't free the argument in vhost_net_ubuf_put_and_wait,
> add an new API for callers that want to free ubufs.
This patch (slightly tweaked to apply it to 3.10.0) fixes the following
backtrace for me:
[exception RIP: vhost_poll_queue+10]
RIP: ffffffffa05d5baa RSP: ffff88013fa83c78 RFLAGS: 00010286
RAX: 00000000c23988bd RBX: ffff88011f504200 RCX: 0000000000000003
RDX: 0000000000000000 RSI: 00000000000000c0 RDI: 0000000000000080
RBP: ffff88013fa83ca8 R8: ffffea0000dc1ba0 R9: 000000000009f414
R10: 00000000000040b4 R11: 0000000000000000 R12: ffff88011ddb0000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff88011dcf5a00
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#9 [ffff88013fa83c80] vhost_zerocopy_callback at ffffffffa05d8dac [vhost_net]
#10 [ffff88013fa83cb0] skb_copy_ubufs at ffffffff8152e0cd
#11 [ffff88013fa83d10] skb_clone at ffffffff8152e214
#12 [ffff88013fa83d30] deliver_clone at ffffffffa05840f5 [bridge]
#13 [ffff88013fa83d58] br_flood at ffffffffa05846ad [bridge]
#14 [ffff88013fa83da0] br_flood_forward at ffffffffa0584875 [bridge]
#15 [ffff88013fa83db0] br_handle_frame_finish at ffffffffa0585514 [bridge]
#16 [ffff88013fa83df0] br_handle_frame at ffffffffa0585825 [bridge]
#17 [ffff88013fa83e28] __netif_receive_skb_core at ffffffff8153b522
#18 [ffff88013fa83e80] __netif_receive_skb at ffffffff8153bae8
#19 [ffff88013fa83ea0] process_backlog at ffffffff8153c61e
#20 [ffff88013fa83ee8] net_rx_action at ffffffff8153bed9
#21 [ffff88013fa83f40] __do_softirq at ffffffff81064997
#22 [ffff88013fa83fb0] call_softirq at ffffffff81651adc
--- <IRQ stack> ---
#23 [ffff88011ea27ca0] netif_rx at ffffffff8153ad99
#24 [ffff88011ea27cd8] netif_rx_ni at ffffffff8153b218
#25 [ffff88011ea27cf0] tun_get_user at ffffffffa05a78ff [tun]
#26 [ffff88011ea27d80] tun_sendmsg at ffffffffa05a7d27 [tun]
#27 [ffff88011ea27da0] handle_tx at ffffffffa05d8830 [vhost_net]
#28 [ffff88011ea27e60] handle_tx_kick at ffffffffa05d8c55 [vhost_net]
#29 [ffff88011ea27e70] vhost_worker at ffffffffa05d578d [vhost_net]
#30 [ffff88011ea27ed0] kthread at ffffffff81080ba0
#31 [ffff88011ea27f50] ret_from_fork at ffffffff8165066c
[exception RIP: unknown or invalid address]
RIP: 0000000000000000 RSP: ffff88011ea27f58 RFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffffff81080ae0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff8801371cfcf8 R8: 0000000000000000 R9: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
Feel free to add when you resubmit to net:
Tested-by: Michele Baldessari <michele@acksyn.org>
--
Michele Baldessari <michele@acksyn.org>
C2A5 9DA3 9961 4FFB E01B D0BC DDD4 DCCB 7515 5C6D
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2013-06-25 14:29 [PATCHv2] vhost-net: fix use-after-free in vhost_net_flush Michael S. Tsirkin
2013-06-26 0:12 ` David Miller
2013-07-03 6:55 ` Michele Baldessari
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