egl/dri2: Guard against invalid fourcc formats

We already reject attempts to import images with invalid fourcc formats
but don't really guard the queries all that well.  This makes us error
out in any calls to eglQueryDmaBufModifiersEXT if the given format is
not a valid fourcc format.  We also add an assert to ensure that drivers
don't advertise any non-fourcc formats.

Cc: mesa-stable@lists.freedesktop.org
Tested-By: Eero Tamminen <eero.t.tamminen@intel.com>
Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>

src/egl/drivers/dri2/egl_dri2.c

@@ -2382,6 +2382,18 @@ dri2_query_dma_buf_formats(_EGLDriver *drv, _EGLDisplay *disp,
                                             formats, count))
       return EGL_FALSE;
 
+   if (max > 0) {
+      /* Assert that all of the formats returned are actually fourcc formats.
+       * Some day, if we want the internal interface function to be able to
+       * return the fake fourcc formats defined in dri_interface.h, we'll have
+       * to do something more clever here to pair the list down to just real
+       * fourcc formats so that we don't leak the fake internal ones.
+       */
+      for (int i = 0; i < *count; i++) {
+         assert(dri2_num_fourcc_format_planes(formats[i]) > 0);
+      }
+   }
+
    return EGL_TRUE;
 }
 
@@ -2392,6 +2404,9 @@ dri2_query_dma_buf_modifiers(_EGLDriver *drv, _EGLDisplay *disp, EGLint format,
 {
    struct dri2_egl_display *dri2_dpy = dri2_egl_display(disp);
 
+   if (dri2_num_fourcc_format_planes(format) == 0)
+      return _eglError(EGL_BAD_PARAMETER, "invalid fourcc format");
+
    if (max < 0)
       return _eglError(EGL_BAD_PARAMETER, "invalid value for max count of formats");