From 9c38d583be2704d7cb5a40e25c9ba0227cbe70cd Mon Sep 17 00:00:00 2001 From: Hawkins Jiawei Date: Fri, 7 Jul 2023 23:27:31 +0800 Subject: [PATCH] vhost: Fix false positive out-of-bounds 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 Message-Id: Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Signed-off-by: fangyi --- hw/virtio/vhost-shadow-virtqueue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c index 8d99edb196..8b5902a8a5 100644 --- a/hw/virtio/vhost-shadow-virtqueue.c +++ b/hw/virtio/vhost-shadow-virtqueue.c @@ -109,7 +109,7 @@ 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, -- 2.27.0