vhost: make sure log_num < in_num
commit 060423bfdee3f8bc6e2c1bac97de24d5415e2bc4 upstream.
The code assumes log_num < in_num everywhere, and that is true as long as
in_num is incremented by descriptor iov count, and log_num by 1. However
this breaks if there's a zero sized descriptor.
As a result, if a malicious guest creates a vring desc with desc.len = 0,
it may cause the host kernel to crash by overflowing the log array. This
bug can be triggered during the VM migration.
There's no need to log when desc.len = 0, so just don't increment log_num
in this case.
Fixes: 3a4d5c94e9
("vhost_net: a kernel-level virtio server")
Cc: stable@vger.kernel.org
Reviewed-by: Lidong Chen <lidongchen@tencent.com>
Signed-off-by: ruippan <ruippan@tencent.com>
Signed-off-by: yongduan <yongduan@tencent.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
8cc953562e
commit
35b29a78cc
1 changed files with 2 additions and 2 deletions
|
@ -1324,7 +1324,7 @@ static int get_indirect(struct vhost_virtqueue *vq,
|
|||
/* If this is an input descriptor, increment that count. */
|
||||
if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE)) {
|
||||
*in_num += ret;
|
||||
if (unlikely(log)) {
|
||||
if (unlikely(log && ret)) {
|
||||
log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
|
||||
log[*log_num].len = vhost32_to_cpu(vq, desc.len);
|
||||
++*log_num;
|
||||
|
@ -1453,7 +1453,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
|
|||
/* If this is an input descriptor,
|
||||
* increment that count. */
|
||||
*in_num += ret;
|
||||
if (unlikely(log)) {
|
||||
if (unlikely(log && ret)) {
|
||||
log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
|
||||
log[*log_num].len = vhost32_to_cpu(vq, desc.len);
|
||||
++*log_num;
|
||||
|
|
Loading…
Add table
Reference in a new issue