57 lines
1.9 KiB
Diff
57 lines
1.9 KiB
Diff
From: "Michael S. Tsirkin" <mst@redhat.com>
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Date: Tue, 25 Jun 2013 17:29:46 +0300
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Subject: vhost-net: fix use-after-free in vhost_net_flush
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Origin: https://git.kernel.org/linus/c38e39c378f46f00ce922dd40a91043a9925c28d
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vhost_net_ubuf_put_and_wait has a confusing name:
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it will actually also free it's argument.
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Thus since commit 1280c27f8e29acf4af2da914e80ec27c3dbd5c01
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"vhost-net: flush outstanding DMAs on memory change"
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vhost_net_flush tries to use the argument after passing it
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to vhost_net_ubuf_put_and_wait, this results
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in use after free.
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To fix, don't free the argument in vhost_net_ubuf_put_and_wait,
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add an new API for callers that want to free ubufs.
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Acked-by: Asias He <asias@redhat.com>
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Acked-by: Jason Wang <jasowang@redhat.com>
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Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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---
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drivers/vhost/net.c | 9 +++++++--
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1 file changed, 7 insertions(+), 2 deletions(-)
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diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
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index f80d3dd..8ca5ac7 100644
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--- a/drivers/vhost/net.c
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+++ b/drivers/vhost/net.c
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@@ -150,6 +150,11 @@ static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs)
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{
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kref_put(&ubufs->kref, vhost_net_zerocopy_done_signal);
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wait_event(ubufs->wait, !atomic_read(&ubufs->kref.refcount));
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+}
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+
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+static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs)
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+{
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+ vhost_net_ubuf_put_and_wait(ubufs);
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kfree(ubufs);
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}
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@@ -948,7 +953,7 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
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mutex_unlock(&vq->mutex);
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if (oldubufs) {
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- vhost_net_ubuf_put_and_wait(oldubufs);
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+ vhost_net_ubuf_put_wait_and_free(oldubufs);
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mutex_lock(&vq->mutex);
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vhost_zerocopy_signal_used(n, vq);
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mutex_unlock(&vq->mutex);
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@@ -966,7 +971,7 @@ err_used:
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rcu_assign_pointer(vq->private_data, oldsock);
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vhost_net_enable_vq(n, vq);
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if (ubufs)
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- vhost_net_ubuf_put_and_wait(ubufs);
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+ vhost_net_ubuf_put_wait_and_free(ubufs);
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err_ubufs:
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fput(sock->file);
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err_vq:
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