From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59777) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cGkgr-0000pP-0T for qemu-devel@nongnu.org; Tue, 13 Dec 2016 05:52:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cGkgn-0005dk-5d for qemu-devel@nongnu.org; Tue, 13 Dec 2016 05:52:09 -0500 Received: from mx6-phx2.redhat.com ([209.132.183.39]:37245) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cGkgm-0005bx-TY for qemu-devel@nongnu.org; Tue, 13 Dec 2016 05:52:05 -0500 Date: Tue, 13 Dec 2016 05:52:01 -0500 (EST) From: Pankaj Gupta Message-ID: <995759159.4566665.1481626321833.JavaMail.zimbra@redhat.com> In-Reply-To: <20161213071439.32322-1-ppandit@redhat.com> References: <20161213071439.32322-1-ppandit@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] display: virtio-gpu-3d: check virgl capabilities max_size List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: P J P Cc: Qemu Developers , Zhenhao Hong , Gerd Hoffmann , Prasad J Pandit > > From: Prasad J Pandit > > Virtio GPU device while processing 'VIRTIO_GPU_CMD_GET_CAPSET' > command, retrieves the maximum capabilities size to fill in the > response object. It continues to fill in capabilities even if > retrieved 'max_size' is zero(0), thus resulting in OOB access. > Add check to avoid it. > > Reported-by: Zhenhao Hong > Signed-off-by: Prasad J Pandit > --- > hw/display/virtio-gpu-3d.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/hw/display/virtio-gpu-3d.c b/hw/display/virtio-gpu-3d.c > index 758d33a..fbfb39f 100644 > --- a/hw/display/virtio-gpu-3d.c > +++ b/hw/display/virtio-gpu-3d.c > @@ -371,11 +371,12 @@ static void virgl_cmd_get_capset(VirtIOGPU *g, > virgl_renderer_get_cap_set(gc.capset_id, &max_ver, > &max_size); > resp = g_malloc(sizeof(*resp) + max_size); > - > - resp->hdr.type = VIRTIO_GPU_RESP_OK_CAPSET; > - virgl_renderer_fill_caps(gc.capset_id, > - gc.capset_version, > - (void *)resp->capset_data); > + if (max_size) { > + resp->hdr.type = VIRTIO_GPU_RESP_OK_CAPSET; > + virgl_renderer_fill_caps(gc.capset_id, > + gc.capset_version, > + (void *)resp->capset_data); > + } > virtio_gpu_ctrl_response(g, cmd, &resp->hdr, sizeof(*resp) + max_size); Just one point here for 'max_size=0', do we don't require to set resp->hdr.type? If yes, other patch on list by 'Li Qiang' can also help to avoid sending garbage value. > g_free(resp); > } > -- > 2.9.3 > > >