From: Mauro Matteo Cascella <mcasc...@redhat.com>
Check the value of mps to avoid potential divide-by-zero later in the function.
Since HCCHAR_MPS is guest controllable, this prevents a malicious/buggy guest
from crashing the QEMU process on the host.
Signed-off-by: Mauro Matteo Cascella <mcasc...@redhat.com>
Reviewed-by: Paul Zimmerman <pauld...@gmail.com>
Reported-by: Gaoning Pan <gaoning....@antgroup.com>
Reported-by: Xingwei Lin <linyi....@antfin.com>
Message-id: 20201015075957.268823-1-mcasc...@redhat.com
Signed-off-by: Gerd Hoffmann <kra...@redhat.com>
---
hw/usb/hcd-dwc2.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/hw/usb/hcd-dwc2.c b/hw/usb/hcd-dwc2.c
index 64c23c1ed084..e1d96acf7ecf 100644
--- a/hw/usb/hcd-dwc2.c
+++ b/hw/usb/hcd-dwc2.c
@@ -250,6 +250,12 @@ static void dwc2_handle_packet(DWC2State *s, uint32_t
devadr, USBDevice *dev,
trace_usb_dwc2_handle_packet(chan, dev, &p->packet, epnum, types[eptype],
dirs[epdir], mps, len, pcnt);
+ if (mps == 0) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "%s: Bad HCCHAR_MPS set to zero\n", __func__);
+ return;
+ }
+
if (eptype == USB_ENDPOINT_XFER_CONTROL && pid == TSIZ_SC_MC_PID_SETUP) {
pid = USB_TOKEN_SETUP;
} else {
--
2.27.0
