unvalidated index in _XkbReadKeyBehaviors() [CVE-2013-1997 7/15]

If the X server returns key behavior indexes outside the range of the number of keys it told us to allocate, out of bounds memory writes could occur. Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com> Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com> Reviewed-by: Matthieu Herrb <matthieu.herrb@laas.fr> Signed-off-by: Julien Cristau <jcristau@debian.org> Backported-to-NX-by: Ulrich Sibiller <uli42@gmx.de>

unvalidated index in _XkbReadKeyBehaviors() [CVE-2013-1997 7/15]
8f2c0508 · Alan Coopersmith · Ulrich Sibiller · 4c19cd0c · 8f2c0508
Commit 8f2c0508 authored Mar 02, 2013 by Alan Coopersmith Committed by Ulrich Sibiller Oct 12, 2016
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XKBGetMap.c nx-X11/lib/X11/XKBGetMap.c +4 -2

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--- a/nx-X11/lib/X11/XKBGetMap.c
+++ b/nx-X11/lib/X11/XKBGetMap.c
@@ -306,8 +306,10 @@ register int i;
 xkbBehaviorWireDesc	*wire;

    if ( rep->totalKeyBehaviors>0 ) {
+	int size = xkb->max_key_code + 1;
+	if ( ((int) rep->firstKeyBehavior + rep->nKeyBehaviors) > size)
+	    return BadLength;
 	if ( xkb->server->behaviors == NULL ) {
-	    int size = xkb->max_key_code+1;
 	    xkb->server->behaviors = _XkbTypedCalloc(size,XkbBehavior);
 	    if (xkb->server->behaviors==NULL)
 		return BadAlloc;
@@ -319,7 +321,7 @@ xkbBehaviorWireDesc	*wire;
 	for (i=0;i<rep->totalKeyBehaviors;i++) {
 	    wire= (xkbBehaviorWireDesc *)_XkbGetReadBufferPtr(buf,
 						SIZEOF(xkbBehaviorWireDesc));
-	    if (wire==NULL)
+	    if (wire==NULL || wire->key >= size)
 		return BadLength;
 	    xkb->server->behaviors[wire->key].type= wire->type;
 	    xkb->server->behaviors[wire->key].data= wire->data;