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[PATCH 03/47] virtio-net: fix use after unmap/free for sg
From: |
Michael Roth |
Subject: |
[PATCH 03/47] virtio-net: fix use after unmap/free for sg |
Date: |
Tue, 14 Dec 2021 18:00:41 -0600 |
From: Jason Wang <jasowang@redhat.com>
When mergeable buffer is enabled, we try to set the num_buffers after
the virtqueue elem has been unmapped. This will lead several issues,
E.g a use after free when the descriptor has an address which belongs
to the non direct access region. In this case we use bounce buffer
that is allocated during address_space_map() and freed during
address_space_unmap().
Fixing this by storing the elems temporarily in an array and delay the
unmap after we set the the num_buffers.
This addresses CVE-2021-3748.
Reported-by: Alexander Bulekov <alxndr@bu.edu>
Fixes: fbe78f4f55c6 ("virtio-net support")
Cc: qemu-stable@nongnu.org
Signed-off-by: Jason Wang <jasowang@redhat.com>
(cherry picked from commit bedd7e93d01961fcb16a97ae45d93acf357e11f6)
Signed-off-by: Michael Roth <michael.roth@amd.com>
---
hw/net/virtio-net.c | 39 ++++++++++++++++++++++++++++++++-------
1 file changed, 32 insertions(+), 7 deletions(-)
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 16d20cdee5..f205331dcf 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1746,10 +1746,13 @@ static ssize_t virtio_net_receive_rcu(NetClientState
*nc, const uint8_t *buf,
VirtIONet *n = qemu_get_nic_opaque(nc);
VirtIONetQueue *q = virtio_net_get_subqueue(nc);
VirtIODevice *vdev = VIRTIO_DEVICE(n);
+ VirtQueueElement *elems[VIRTQUEUE_MAX_SIZE];
+ size_t lens[VIRTQUEUE_MAX_SIZE];
struct iovec mhdr_sg[VIRTQUEUE_MAX_SIZE];
struct virtio_net_hdr_mrg_rxbuf mhdr;
unsigned mhdr_cnt = 0;
- size_t offset, i, guest_offset;
+ size_t offset, i, guest_offset, j;
+ ssize_t err;
if (!virtio_net_can_receive(nc)) {
return -1;
@@ -1780,6 +1783,12 @@ static ssize_t virtio_net_receive_rcu(NetClientState
*nc, const uint8_t *buf,
total = 0;
+ if (i == VIRTQUEUE_MAX_SIZE) {
+ virtio_error(vdev, "virtio-net unexpected long buffer chain");
+ err = size;
+ goto err;
+ }
+
elem = virtqueue_pop(q->rx_vq, sizeof(VirtQueueElement));
if (!elem) {
if (i) {
@@ -1791,7 +1800,8 @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc,
const uint8_t *buf,
n->guest_hdr_len, n->host_hdr_len,
vdev->guest_features);
}
- return -1;
+ err = -1;
+ goto err;
}
if (elem->in_num < 1) {
@@ -1799,7 +1809,8 @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc,
const uint8_t *buf,
"virtio-net receive queue contains no in buffers");
virtqueue_detach_element(q->rx_vq, elem, 0);
g_free(elem);
- return -1;
+ err = -1;
+ goto err;
}
sg = elem->in_sg;
@@ -1836,12 +1847,13 @@ static ssize_t virtio_net_receive_rcu(NetClientState
*nc, const uint8_t *buf,
if (!n->mergeable_rx_bufs && offset < size) {
virtqueue_unpop(q->rx_vq, elem, total);
g_free(elem);
- return size;
+ err = size;
+ goto err;
}
- /* signal other side */
- virtqueue_fill(q->rx_vq, elem, total, i++);
- g_free(elem);
+ elems[i] = elem;
+ lens[i] = total;
+ i++;
}
if (mhdr_cnt) {
@@ -1851,10 +1863,23 @@ static ssize_t virtio_net_receive_rcu(NetClientState
*nc, const uint8_t *buf,
&mhdr.num_buffers, sizeof mhdr.num_buffers);
}
+ for (j = 0; j < i; j++) {
+ /* signal other side */
+ virtqueue_fill(q->rx_vq, elems[j], lens[j], j);
+ g_free(elems[j]);
+ }
+
virtqueue_flush(q->rx_vq, i);
virtio_notify(vdev, q->rx_vq);
return size;
+
+err:
+ for (j = 0; j < i; j++) {
+ g_free(elems[j]);
+ }
+
+ return err;
}
static ssize_t virtio_net_do_receive(NetClientState *nc, const uint8_t *buf,
--
2.25.1
- [PATCH 31/47] hw/scsi/scsi-disk: MODE_PAGE_ALLS not allowed in MODE SELECT commands, (continued)
- [PATCH 31/47] hw/scsi/scsi-disk: MODE_PAGE_ALLS not allowed in MODE SELECT commands, Michael Roth, 2021/12/14
- [PATCH 32/47] hw: m68k: virt: Add compat machine for 6.1, Michael Roth, 2021/12/14
- [PATCH 33/47] rcu: Introduce force_rcu notifier, Michael Roth, 2021/12/14
- [PATCH 34/47] accel/tcg: Register a force_rcu notifier, Michael Roth, 2021/12/14
- [PATCH 35/47] pcie: rename 'native-hotplug' to 'x-native-hotplug', Michael Roth, 2021/12/14
- [PATCH 36/47] virtio: use virtio accessor to access packed descriptor flags, Michael Roth, 2021/12/14
- [PATCH 37/47] virtio: use virtio accessor to access packed event, Michael Roth, 2021/12/14
- [PATCH 38/47] vfio: Fix memory leak of hostwin, Michael Roth, 2021/12/14
- [PATCH 39/47] nbd/server: Don't complain on certain client disconnects, Michael Roth, 2021/12/14
- [PATCH 40/47] hw/nvme: fix buffer overrun in nvme_changed_nslist (CVE-2021-3947), Michael Roth, 2021/12/14
- [PATCH 03/47] virtio-net: fix use after unmap/free for sg,
Michael Roth <=
- [PATCH 41/47] chardev/wctable: don't free the instance in wctablet_chr_finalize, Michael Roth, 2021/12/14
- [PATCH 42/47] hw/block/fdc: Extract blk_create_empty_drive(), Michael Roth, 2021/12/14
- [PATCH 43/47] hw/block/fdc: Kludge missing floppy drive to fix CVE-2021-20196, Michael Roth, 2021/12/14
- [PATCH 44/47] tests/qtest/fdc-test: Add a regression test for CVE-2021-20196, Michael Roth, 2021/12/14
- [PATCH 45/47] virtio-blk: Fix clean up of host notifiers for single MR transaction., Michael Roth, 2021/12/14
- [PATCH 46/47] net: vmxnet3: validate configuration values during activate (CVE-2021-20203), Michael Roth, 2021/12/14
- [PATCH 47/47] e1000: fix tx re-entrancy problem, Michael Roth, 2021/12/14
- [PATCH 04/47] qemu-nbd: Change default cache mode to writeback, Michael Roth, 2021/12/14
- [PATCH 05/47] hmp: Unbreak "change vnc", Michael Roth, 2021/12/14
- [PATCH 06/47] virtio-mem-pci: Fix memory leak when creating MEMORY_DEVICE_SIZE_CHANGE event, Michael Roth, 2021/12/14