diff options
| -rw-r--r-- | src/dmx.c | 34 |
1 files changed, 28 insertions, 6 deletions
@@ -524,6 +524,7 @@ Bool DMXGetWindowAttributes(Display *dpy, Window window, CARD32 *windows; /* Must match protocol size */ XRectangle *pos; /* Must match protocol size */ XRectangle *vis; /* Must match protocol size */ + Bool ret = False; DMXCheckExtension(dpy, info, False); @@ -538,11 +539,30 @@ Bool DMXGetWindowAttributes(Display *dpy, Window window, return False; } - /* FIXME: check for NULL? */ - screens = Xmalloc(rep.screenCount * sizeof(*screens)); - windows = Xmalloc(rep.screenCount * sizeof(*windows)); - pos = Xmalloc(rep.screenCount * sizeof(*pos)); - vis = Xmalloc(rep.screenCount * sizeof(*vis)); + /* + * rep.screenCount is a CARD32 so could be as large as 2^32 + * The X11 protocol limits the total screen size to 64k x 64k, + * and no screen can be smaller than a pixel. While technically + * that means we could theoretically reach 2^32 screens, and that's + * not even taking overlap into account, 64k seems far larger than + * any reasonable configuration, so we limit to that to prevent both + * integer overflow in the size calculations, and bad X server + * responses causing massive memory allocation. + */ + if (rep.screenCount < 65536) { + screens = Xmalloc(rep.screenCount * sizeof(*screens)); + windows = Xmalloc(rep.screenCount * sizeof(*windows)); + pos = Xmalloc(rep.screenCount * sizeof(*pos)); + vis = Xmalloc(rep.screenCount * sizeof(*vis)); + } else { + screens = windows = NULL; + pos = vis = NULL; + } + + if (!screens || !windows || !pos || !vis) { + _XEatDataWords(dpy, rep.length); + goto end; + } _XRead(dpy, (char *)screens, rep.screenCount * sizeof(*screens)); _XRead(dpy, (char *)windows, rep.screenCount * sizeof(*windows)); @@ -558,7 +578,9 @@ Bool DMXGetWindowAttributes(Display *dpy, Window window, inf->pos = pos[current]; inf->vis = vis[current]; } + ret = True; + end: Xfree(vis); Xfree(pos); Xfree(windows); @@ -566,7 +588,7 @@ Bool DMXGetWindowAttributes(Display *dpy, Window window, UnlockDisplay(dpy); SyncHandle(); - return True; + return ret; } /** If the DMXGetDesktopAttributes protocol request returns information |