diff options
Diffstat (limited to 'libXinerama/src/Xinerama.c')
| -rw-r--r-- | libXinerama/src/Xinerama.c | 61 |
1 files changed, 45 insertions, 16 deletions
diff --git a/libXinerama/src/Xinerama.c b/libXinerama/src/Xinerama.c index 7d7e4d856..67a35b578 100644 --- a/libXinerama/src/Xinerama.c +++ b/libXinerama/src/Xinerama.c @@ -23,6 +23,10 @@ dealings in this Software without prior written authorization from Digital Equipment Corporation. ******************************************************************/ +#ifdef HAVE_CONFIG_H +# include "config.h" +#endif + #include <X11/Xlibint.h> #include <X11/Xutil.h> #include <X11/extensions/Xext.h> @@ -31,6 +35,19 @@ Equipment Corporation. #include <X11/extensions/panoramiXproto.h> #include <X11/extensions/Xinerama.h> +#ifndef HAVE__XEATDATAWORDS +#include <X11/Xmd.h> /* for LONG64 on 64-bit platforms */ +#include <limits.h> + +static inline void _XEatDataWords(Display *dpy, unsigned long n) +{ +# ifndef LONG64 + if (n >= (ULONG_MAX >> 2)) + _XIOError(dpy); +# endif + _XEatData (dpy, n << 2); +} +#endif static XExtensionInfo _panoramiX_ext_info_data; static XExtensionInfo *panoramiX_ext_info = &_panoramiX_ext_info_data; @@ -286,24 +303,36 @@ XineramaQueryScreens( return NULL; } - if(rep.number) { - if((scrnInfo = Xmalloc(sizeof(XineramaScreenInfo) * rep.number))) { + /* + * rep.number 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, Xorg is currently limited + * to 16 screens, and few known servers have a much higher limit, + * so 1024 seems more than enough to prevent both integer overflow + * and insane X server responses causing massive memory allocation. + */ + if ((rep.number > 0) && (rep.number <= 1024)) + scrnInfo = Xmalloc(sizeof(XineramaScreenInfo) * rep.number); + if (scrnInfo != NULL) { + int i; + + for (i = 0; i < rep.number; i++) { xXineramaScreenInfo scratch; - int i; - - for(i = 0; i < rep.number; i++) { - _XRead(dpy, (char*)(&scratch), sz_XineramaScreenInfo); - scrnInfo[i].screen_number = i; - scrnInfo[i].x_org = scratch.x_org; - scrnInfo[i].y_org = scratch.y_org; - scrnInfo[i].width = scratch.width; - scrnInfo[i].height = scratch.height; - } - - *number = rep.number; - } else - _XEatData(dpy, rep.length << 2); + + _XRead(dpy, (char*)(&scratch), sz_XineramaScreenInfo); + + scrnInfo[i].screen_number = i; + scrnInfo[i].x_org = scratch.x_org; + scrnInfo[i].y_org = scratch.y_org; + scrnInfo[i].width = scratch.width; + scrnInfo[i].height = scratch.height; + } + + *number = rep.number; } else { + _XEatDataWords(dpy, rep.length); *number = 0; } |