[PATCH] VSOCK: fix vhost virtio_vsock_pkt use-after-free
From: Stefan Hajnoczi <stefanha@redhat.com>
Date: 2016-08-04 13:52:53
Also in:
kvm
Subsystem:
the rest, virtio and vhost vsock driver, virtio host (vhost) · Maintainers:
Linus Torvalds, Stefan Hajnoczi, Stefano Garzarella, "Michael S. Tsirkin", Jason Wang
Stash the packet length in a local variable before handing over ownership of the packet to virtio_transport_recv_pkt() or virtio_transport_free_pkt(). This patch solves the use-after-free since pkt is no longer guaranteed to be alive. Reported-by: Dan Carpenter <redacted> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> --- drivers/vhost/vsock.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 0ddf3a2..e3b30ea 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c@@ -307,6 +307,8 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work) vhost_disable_notify(&vsock->dev, vq); for (;;) { + u32 len; + if (!vhost_vsock_more_replies(vsock)) { /* Stop tx until the device processes already * pending replies. Leave tx virtqueue
@@ -334,13 +336,15 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work) continue; } + len = pkt->len; + /* Only accept correctly addressed packets */ if (le64_to_cpu(pkt->hdr.src_cid) == vsock->guest_cid) virtio_transport_recv_pkt(pkt); else virtio_transport_free_pkt(pkt); - vhost_add_used(vq, head, sizeof(pkt->hdr) + pkt->len); + vhost_add_used(vq, head, sizeof(pkt->hdr) + len); added = true; }
--
2.7.4