diff options
| author | yongduan <yongduan@tencent.com> | 2019-09-11 17:44:24 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-09-16 08:13:36 +0200 |
| commit | 35b29a78cc9b2523f6b0c080e6b44d2eeb367023 (patch) | |
| tree | 0885f335b82ee01532bb5c4117f7149fa539bbd2 /lib/bcd.c | |
| parent | 8cc953562e2e293575514c40806eee438a967364 (diff) | |
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: 3a4d5c94e959 ("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>
Diffstat (limited to 'lib/bcd.c')
0 files changed, 0 insertions, 0 deletions