dhclient - Properly handle zero-length option hints.

- There was a possible division by zero if a server
  sends us a broken option hints for the proper fix.

Taken-from: OpenBSD

diff --git a/sbin/dhclient/options.c b/sbin/dhclient/options.c
index c77e315..14a9858 100644 (file)
--- a/sbin/dhclient/options.c
+++ b/sbin/dhclient/options.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: src/sbin/dhclient/options.c,v 1.37 2009/03/10 23:19:36 krw Exp $ */
+/*     $OpenBSD: src/sbin/dhclient/options.c,v 1.38 2011/04/17 19:57:23 phessler Exp $ */
 
 /* DHCP options parsing and reassembly. */
 
@@ -212,6 +212,13 @@ pretty_print_option(unsigned int code, unsigned char *data, int len,
                        --numelem;
                        fmtbuf[i] = 0;
                        numhunk = 0;
+                       if (hunksize == 0) {
+                               warning("%s: no size indicator before A"
+                                   " in format string: %s",
+                                   dhcp_options[code].name,
+                                   dhcp_options[code].format);
+                               return ("<fmt error>");
+                       }
                        break;
                case 'X':
                        for (k = 0; k < len; k++)