From 306ca006a54c5f74a6fe90eb794efa06ff33b259 Mon Sep 17 00:00:00 2001 From: Alan Coopersmith Date: Sat, 2 Mar 2013 15:08:21 -0800 Subject: integer overflow in XGetModifierMapping() [CVE-2013-1981 13/13] Ensure that we don't underallocate when the server claims a very large reply Signed-off-by: Alan Coopersmith Reviewed-by: Matthieu Herrb Signed-off-by: Julien Cristau Backported-to-NX-by: Ulrich Sibiller --- nx-X11/lib/X11/ModMap.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/nx-X11/lib/X11/ModMap.c b/nx-X11/lib/X11/ModMap.c index c99bfdd5f..122ca80db 100644 --- a/nx-X11/lib/X11/ModMap.c +++ b/nx-X11/lib/X11/ModMap.c @@ -28,6 +28,7 @@ in this Software without prior written authorization from The Open Group. #include #endif #include "Xlibint.h" +#include XModifierKeymap * XGetModifierMapping(register Display *dpy) @@ -41,13 +42,17 @@ XGetModifierMapping(register Display *dpy) GetEmptyReq(GetModifierMapping, req); (void) _XReply (dpy, (xReply *)&rep, 0, xFalse); - nbytes = (unsigned long)rep.length << 2; - res = (XModifierKeymap *) Xmalloc(sizeof (XModifierKeymap)); - if (res) res->modifiermap = (KeyCode *) Xmalloc ((unsigned) nbytes); + if (rep.length < (LONG_MAX >> 2)) { + nbytes = (unsigned long)rep.length << 2; + res = Xmalloc(sizeof (XModifierKeymap)); + if (res) + res->modifiermap = Xmalloc (nbytes); + } else + res = NULL; if ((! res) || (! res->modifiermap)) { if (res) Xfree((char *) res); res = (XModifierKeymap *) NULL; - _XEatData(dpy, nbytes); + _XEatDataWords(dpy, rep.length); } else { _XReadPad(dpy, (char *) res->modifiermap, (long) nbytes); res->max_keypermod = rep.numKeyPerModifier; -- cgit v1.2.3