usb: control buffer fixes

Windows allows control transfers to pass up to 4k of data, so raise our
control buffer size to 4k. For control out transfers the usb core code copies
the control request data to a buffer before calling the device's handle_control
callback. Add a check for overflowing the buffer before copying the data.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

2 files changed, 7 insertions, 1 deletions

diff --git a/hw/usb.c b/hw/usb.c
index 82a6217..d8c0a75 100644
--- a/hw/usb.c
+++ b/hw/usb.c
@@ -93,6 +93,12 @@ static int do_token_setup(USBDevice *s, USBPacket *p)
             s->setup_len = ret;
         s->setup_state = SETUP_STATE_DATA;
     } else {
+        if (s->setup_len > sizeof(s->data_buf)) {
+            fprintf(stderr,
+                "usb_generic_handle_packet: ctrl buffer too small (%d > %zu)\n",
+                s->setup_len, sizeof(s->data_buf));
+            return USB_RET_STALL;
+        }
         if (s->setup_len == 0)
             s->setup_state = SETUP_STATE_ACK;
         else
diff --git a/hw/usb.h b/hw/usb.h
index d3d755d..22bb338 100644
--- a/hw/usb.h
+++ b/hw/usb.h
@@ -167,7 +167,7 @@ struct USBDevice {
 
     int32_t state;
     uint8_t setup_buf[8];
-    uint8_t data_buf[1024];
+    uint8_t data_buf[4096];
     int32_t remote_wakeup;
     int32_t setup_state;
     int32_t setup_len;