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virtio-crypto: don't modify elem->in/out_sg

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A number of iov_discard_front/back() operations are made by
virtio-crypto. The elem->in/out_sg iovec arrays are modified by these
operations, resulting virtqueue_unmap_sg() calls on different addresses
than were originally mapped.

This is problematic because dirty memory may not be logged correctly,
MemoryRegion refcounts may be leaked, and the non-RAM bounce buffer can
be leaked.

Take a copy of the elem->in/out_sg arrays so that the originals are
preserved. The iov_discard_undo() API could be used instead (with better
performance) but requires careful auditing of the code, so do the simple
thing instead.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Li Qiang <liq3ea@gmail.com>
Message-Id: <20200917094455.822379-4-stefanha@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2020-09-17 10:44:55 +01:00
parent 7bd04a041a
commit 8080747748
1 changed files with 14 additions and 3 deletions
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17
hw/virtio/virtio-crypto.c
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@ -228,6 +228,8 @@ static void virtio_crypto_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
size_t s;
for (;;) {
g_autofree struct iovec *out_iov_copy = NULL;
elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
if (!elem) {
break;
@ -240,9 +242,12 @@ static void virtio_crypto_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
}
out_num = elem->out_num;
out_iov = elem->out_sg;
out_iov_copy = g_memdup(elem->out_sg, sizeof(out_iov[0]) * out_num);
out_iov = out_iov_copy;
in_num = elem->in_num;
in_iov = elem->in_sg;
if (unlikely(iov_to_buf(out_iov, out_num, 0, &ctrl, sizeof(ctrl))
!= sizeof(ctrl))) {
virtio_error(vdev, "virtio-crypto request ctrl_hdr too short");
@ -582,6 +587,8 @@ virtio_crypto_handle_request(VirtIOCryptoReq *request)
int queue_index = virtio_crypto_vq2q(virtio_get_queue_index(request->vq));
struct virtio_crypto_op_data_req req;
int ret;
g_autofree struct iovec *in_iov_copy = NULL;
g_autofree struct iovec *out_iov_copy = NULL;
struct iovec *in_iov;
struct iovec *out_iov;
unsigned in_num;
@ -598,9 +605,13 @@ virtio_crypto_handle_request(VirtIOCryptoReq *request)
}
out_num = elem->out_num;
out_iov = elem->out_sg;
out_iov_copy = g_memdup(elem->out_sg, sizeof(out_iov[0]) * out_num);
out_iov = out_iov_copy;
in_num = elem->in_num;
in_iov = elem->in_sg;
in_iov_copy = g_memdup(elem->in_sg, sizeof(in_iov[0]) * in_num);
in_iov = in_iov_copy;
if (unlikely(iov_to_buf(out_iov, out_num, 0, &req, sizeof(req))
!= sizeof(req))) {
virtio_error(vdev, "virtio-crypto request outhdr too short");