Bug#776096: bsdmainutils: hexdump fails if format_string contains backslash

[Rémi Rampin]

There's actually another bug in escape(): the terminating null byte
doesn't break out of the loop if the last character is a backslash.
You can't see the garbage that gets copied to the buffer because the
null byte gets copied, the the overrun does happen.

New patch that also addresses that.

--- bsdmainutils/usr.bin/hexdump/parse.c        2015-09-04 09:04:57.000000000 
-0400
+++ bsdmainutils/usr.bin/hexdump/parse.c        2015-09-04 10:12:27.705336045 
-0400
@@ -454,10 +454,6 @@
 
        /* alphabetic escape sequences have to be done in place */
        for (p2 = p1;; ++p1, ++p2) {
-               if (!*p1) {
-                       *p2 = *p1;
-                       break;
-               }
                if (*p1 == '\\')
                        switch(*++p1) {
                        case 'a':
@@ -486,6 +482,10 @@
                                *p2 = *p1;
                                break;
                        }
+               else
+                       *p2 = *p1;
+               if(!*p1)
+                       break;
        }
 }