File parse_boolean-NULL-end.patch of Package xen.8390

cmdline: fix parse_boolean() for NULL incoming end pointer

Use the calculated lengths instead of pointers, as 'e' being NULL will
otherwise cause undue parsing failures.

Reported-by: Karl Johnson <karljohnson.it@gmail.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>

--- sle12sp2.orig/xen/common/kernel.c	2018-03-28 16:33:59.000000000 +0200
+++ sle12sp2/xen/common/kernel.c	2018-07-16 10:36:03.000000000 +0200
@@ -193,10 +193,11 @@ int parse_boolean(const char *name, cons
         char buf[8];
 
         s += nlen + 1;
-        if ( e <= s || e - s >= ARRAY_SIZE(buf) )
+        slen -= nlen + 1;
+        if ( slen >= ARRAY_SIZE(buf) )
             return -1;
-        memcpy(buf, s, e - s);
-        buf[e - s] = 0;
+        memcpy(buf, s, slen);
+        buf[slen] = 0;
         return parse_bool(buf);
     }