diff mbox series

[PULL,61/66] vhost: Fix false positive out-of-bounds

Message ID b77a5f22aca4cef2dc893ea544841bdd95dc83ba.1689030052.git.mst@redhat.com
State New
Headers show
Series [PULL,01/66] vdpa: Remove status in reset tracing | expand

Commit Message

Michael S. Tsirkin July 10, 2023, 11:05 p.m. UTC 
From: Hawkins Jiawei <yin31149@gmail.com>

QEMU uses vhost_svq_translate_addr() to translate addresses
between the QEMU's virtual address and the SVQ IOVA. In order
to validate this translation, QEMU checks whether the translated
range falls within the mapped range.

Yet the problem is that, the value of `needle_last`, which is calculated
by `needle.translated_addr + iovec[i].iov_len`, should represent the
exclusive boundary of the translated range, rather than the last
inclusive addresses of the range. Consequently, QEMU fails the check
when the translated range matches the size of the mapped range.

This patch solves this problem by fixing the `needle_last` value to
the last inclusive address of the translated range.

Note that this bug cannot be triggered at the moment, because QEMU
is unable to translate such a big range due to the truncation of
the CVQ command in vhost_vdpa_net_handle_ctrl_avail().

Fixes: 34e3c94eda ("vdpa: Add custom IOTLB translations to SVQ")
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
Message-Id: <ee31c5420ffc8e6a29705ddd30badb814ddbae1d.1688743107.git.yin31149@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index 1b1d85306c..49e5aed931 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -111,7 +111,7 @@  static bool vhost_svq_translate_addr(const VhostShadowVirtqueue *svq,
         addrs[i] = map->iova + off;
 
         needle_last = int128_add(int128_make64(needle.translated_addr),
-                                 int128_make64(iovec[i].iov_len));
+                                 int128_makes64(iovec[i].iov_len - 1));
         map_last = int128_make64(map->translated_addr + map->size);
         if (unlikely(int128_gt(needle_last, map_last))) {
             qemu_log_mask(LOG_GUEST_ERROR,