Make XGetWindowProperty() always initialize returned values

Avoids memory corruption and other errors when callers access them without checking to see if XGetWindowProperty() returned an error value. Callers are still required to check for errors, this just reduces the damage when they don't. 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>

Make XGetWindowProperty() always initialize returned values
e03f3922 · Alan Coopersmith · Ulrich Sibiller · b2071058 · e03f3922
Commit e03f3922 authored Mar 09, 2013 by Alan Coopersmith Committed by Ulrich Sibiller Oct 12, 2016
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GetProp.c nx-X11/lib/X11/GetProp.c +7 -1

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--- a/nx-X11/lib/X11/GetProp.c
+++ b/nx-X11/lib/X11/GetProp.c
@@ -49,6 +49,13 @@ XGetWindowProperty(
    register xGetPropertyReq *req;
    xError error;

+    /* Always initialize return values, in case callers fail to initialize
+       them and fail to check the return code for an error. */
+    *actual_type = None;
+    *actual_format = 0;
+    *nitems = *bytesafter = 0L;
+    *prop = (unsigned char *) NULL;
+
    LockDisplay(dpy);
    GetReq (GetProperty, req);
    req->window = w;
@@ -65,7 +72,6 @@ XGetWindowProperty(
 	return (1);	/* not Success */
 	}

-    *prop = (unsigned char *) NULL;
    if (reply.propertyType != None) {
 	unsigned long nbytes, netbytes;
 	int format = reply.format;