73 lines
2.9 KiB
Diff
73 lines
2.9 KiB
Diff
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From 912641a75955a75f37ab8695a0753b1571762717 Mon Sep 17 00:00:00 2001
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From: Jason Wang <jasowang@redhat.com>
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Date: Tue, 2 Jan 2024 11:29:01 +0800
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Subject: [PATCH] virtio-net: correctly copy vnet header when flushing TX
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(CVE-2023-6693)
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When HASH_REPORT is negotiated, the guest_hdr_len might be larger than
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the size of the mergeable rx buffer header. Using
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virtio_net_hdr_mrg_rxbuf during the header swap might lead a stack
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overflow in this case. Fixing this by using virtio_net_hdr_v1_hash
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instead.
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Reported-by: Xiao Lei <leixiao.nop@zju.edu.cn>
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Cc: Yuri Benditovich <yuri.benditovich@daynix.com>
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Cc: qemu-stable@nongnu.org
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Cc: Mauro Matteo Cascella <mcascell@redhat.com>
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Fixes: CVE-2023-6693
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Fixes: e22f0603fb2f ("virtio-net: reference implementation of hash report")
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Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
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Signed-off-by: Jason Wang <jasowang@redhat.com>
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---
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hw/net/virtio-net.c | 13 +++++++++----
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1 file changed, 9 insertions(+), 4 deletions(-)
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diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
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index 80c56f0cfc..73024babd4 100644
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--- a/hw/net/virtio-net.c
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+++ b/hw/net/virtio-net.c
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@@ -674,6 +674,11 @@ static void virtio_net_set_mrg_rx_bufs(VirtIONet *n, int mergeable_rx_bufs,
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n->mergeable_rx_bufs = mergeable_rx_bufs;
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+ /*
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+ * Note: when extending the vnet header, please make sure to
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+ * change the vnet header copying logic in virtio_net_flush_tx()
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+ * as well.
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+ */
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if (version_1) {
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n->guest_hdr_len = hash_report ?
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sizeof(struct virtio_net_hdr_v1_hash) :
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@@ -2693,7 +2698,7 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q)
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ssize_t ret;
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unsigned int out_num;
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struct iovec sg[VIRTQUEUE_MAX_SIZE], sg2[VIRTQUEUE_MAX_SIZE + 1], *out_sg;
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- struct virtio_net_hdr_mrg_rxbuf mhdr;
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+ struct virtio_net_hdr_v1_hash vhdr;
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elem = virtqueue_pop(q->tx_vq, sizeof(VirtQueueElement));
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if (!elem) {
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@@ -2710,7 +2715,7 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q)
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}
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if (n->has_vnet_hdr) {
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- if (iov_to_buf(out_sg, out_num, 0, &mhdr, n->guest_hdr_len) <
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+ if (iov_to_buf(out_sg, out_num, 0, &vhdr, n->guest_hdr_len) <
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n->guest_hdr_len) {
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virtio_error(vdev, "virtio-net header incorrect");
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virtqueue_detach_element(q->tx_vq, elem, 0);
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@@ -2718,8 +2723,8 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q)
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return -EINVAL;
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}
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if (n->needs_vnet_hdr_swap) {
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- virtio_net_hdr_swap(vdev, (void *) &mhdr);
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- sg2[0].iov_base = &mhdr;
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+ virtio_net_hdr_swap(vdev, (void *) &vhdr);
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+ sg2[0].iov_base = &vhdr;
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sg2[0].iov_len = n->guest_hdr_len;
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out_num = iov_copy(&sg2[1], ARRAY_SIZE(sg2) - 1,
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out_sg, out_num,
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--
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2.27.0
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