Hi On Tue, Apr 5, 2022 at 2:43 PM Mauro Matteo Cascella <mcasc...@redhat.com> wrote:
> Prevent potential integer overflow by limiting 'width' and 'height' to > 512x512. Also change 'datasize' type to size_t. Refer to security > advisory https://starlabs.sg/advisories/22-4206/ for more information. > > Fixes: CVE-2022-4206 > Signed-off-by: Mauro Matteo Cascella <mcasc...@redhat.com> > --- > hw/display/qxl-render.c | 7 +++++++ > ui/cursor.c | 12 +++++++++++- > 2 files changed, 18 insertions(+), 1 deletion(-) > > diff --git a/hw/display/qxl-render.c b/hw/display/qxl-render.c > index d28849b121..dc3c4edd05 100644 > --- a/hw/display/qxl-render.c > +++ b/hw/display/qxl-render.c > @@ -247,6 +247,13 @@ static QEMUCursor *qxl_cursor(PCIQXLDevice *qxl, > QXLCursor *cursor, > size_t size; > > c = cursor_alloc(cursor->header.width, cursor->header.height); > + > + if (!c) { > + qxl_set_guest_bug(qxl, "%s: cursor %ux%u alloc error", __func__, > + cursor->header.width, cursor->header.height); > + goto fail; > + } > + > c->hot_x = cursor->header.hot_spot_x; > c->hot_y = cursor->header.hot_spot_y; > switch (cursor->header.type) { > diff --git a/ui/cursor.c b/ui/cursor.c > index 1d62ddd4d0..7cfb08a030 100644 > --- a/ui/cursor.c > +++ b/ui/cursor.c > @@ -46,6 +46,13 @@ static QEMUCursor *cursor_parse_xpm(const char *xpm[]) > > /* parse pixel data */ > c = cursor_alloc(width, height); > + > + if (!c) { > + fprintf(stderr, "%s: cursor %ux%u alloc error\n", > + __func__, width, height); > + return NULL; > + } > I think you could simply abort() in this function. It is used with static data (ui/cursor*.xpm) + > for (pixel = 0, y = 0; y < height; y++, line++) { > for (x = 0; x < height; x++, pixel++) { > idx = xpm[line][x]; > @@ -91,7 +98,10 @@ QEMUCursor *cursor_builtin_left_ptr(void) > QEMUCursor *cursor_alloc(int width, int height) > { > QEMUCursor *c; > - int datasize = width * height * sizeof(uint32_t); > + size_t datasize = width * height * sizeof(uint32_t); > + > + if (width > 512 || height > 512) > + return NULL; > > c = g_malloc0(sizeof(QEMUCursor) + datasize); > c->width = width; > -- > 2.35.1 > > > lgtm otherwise -- Marc-André Lureau
