[Mesa-stable] [PATCH] egl: avoid eglCreatePlatform*Surface{EXT, } crash with invalid dpy

[Tapani Pälli]

Yeah, _eglLookupDisplay seems to return NULL indeed in this case;

Reviewed-by: Tapani Pälli <tapani.palli at intel.com>

On 08/08/2017 05:55 PM, Emil Velikov wrote:
> From: Emil Velikov <emil.velikov at collabora.com>
>
> If we have an invalid display fed into the functions, the display lookup
> will return NULL. Thus as we attempt to get the platform type, we'll
> deref. it leading to a crash.
>
> Keep in mind that this will not happen if Mesa is built without X11 or
> when the legacy eglCreate*Surface codepaths are used.
>
> An similar check was added with earlier commit 5e97b8f5ce9 ("egl: Fix
> crashes in eglCreate*Surface), although it was only applicable when the
> surfaceless platform is built.
>
> Cc: mesa-stable at lists.freedesktop.org
> Cc: Tapani Pälli <tapani.palli at intel.com>
> Cc: Chad Versace <chadversary at chromium.org>
> Signed-off-by: Emil Velikov <emil.velikov at collabora.com>
> ---
>   src/egl/main/eglapi.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/src/egl/main/eglapi.c b/src/egl/main/eglapi.c
> index c5e3955c48c..8146009da4f 100644
> --- a/src/egl/main/eglapi.c
> +++ b/src/egl/main/eglapi.c
> @@ -923,7 +923,7 @@ static void *
>   _fixupNativeWindow(_EGLDisplay *disp, void *native_window)
>   {
>   #ifdef HAVE_X11_PLATFORM
> -   if (disp->Platform == _EGL_PLATFORM_X11 && native_window != NULL) {
> +   if (disp && disp->Platform == _EGL_PLATFORM_X11 && native_window != NULL) {
>         /* The `native_window` parameter for the X11 platform differs between
>          * eglCreateWindowSurface() and eglCreatePlatformPixmapSurfaceEXT(). In
>          * eglCreateWindowSurface(), the type of `native_window` is an Xlib
> @@ -985,7 +985,7 @@ _fixupNativePixmap(_EGLDisplay *disp, void *native_pixmap)
>          * `Pixmap*`.  Convert `Pixmap*` to `Pixmap` because that's what
>          * dri2_x11_create_pixmap_surface() expects.
>          */
> -   if (disp->Platform == _EGL_PLATFORM_X11 && native_pixmap != NULL)
> +   if (disp && disp->Platform == _EGL_PLATFORM_X11 && native_pixmap != NULL)
>         return (void *)(* (Pixmap*) native_pixmap);
>   #endif
>      return native_pixmap;