From: Shawn Routhier <sar@isc.org>
Date: Tue, 20 Apr 2010 23:20:20 +0000 (+0000)
Subject: Don't include lease time information in the response to a DHCPINFORM
X-Git-Tag: v4_3_0a1~287
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1e05d095c26e721257180c7c82d5f6fa5c07e298;p=thirdparty%2Fdhcp.git

Don't include lease time information in the response to a DHCPINFORM
request.  We do this by removing any time information from the option
cache before building the reponse packet.  Bug ticket 21092.
---

diff --git a/RELNOTES b/RELNOTES
index addae6b02..c3b0684f3 100644
--- a/RELNOTES
+++ b/RELNOTES
@@ -39,6 +39,11 @@ The system has only been tested on Linux, FreeBSD, and Solaris, and may not
 work on other platforms. Please report any problems and suggested fixes to
 <dhcp-users@isc.org>.
 
+			Changes since 4.2.0b1
+
+- Prohibit including lease time information in a response to a DHCP INFORM
+  Bug ticket 21092.
+
 			Changes since 4.2.0a2
 
 - Update the fsync code to work with the changes to the DDNS code.  It now
diff --git a/common/options.c b/common/options.c
index 52003ab6f..a566708bb 100644
--- a/common/options.c
+++ b/common/options.c
@@ -3,7 +3,7 @@
    DHCP options parsing and reassembly. */
 
 /*
- * Copyright (c) 2004-2009 by Internet Systems Consortium, Inc. ("ISC")
+ * Copyright (c) 2004-2010 by Internet Systems Consortium, Inc. ("ISC")
  * Copyright (c) 1995-2003 by Internet Software Consortium
  *
  * Permission to use, copy, modify, and distribute this software for any
@@ -637,6 +637,8 @@ cons_options(struct packet *inpacket, struct dhcp_packet *outpacket,
 	/*
 	 * Preload the option priority list with protocol-mandatory options.
 	 * This effectively gives these options the highest priority.
+	 * This provides the order for any available options, the option
+	 * must be in the option cache in order to actually be included.
 	 */
 	priority_len = 0;
 	priority_list[priority_len++] = DHO_DHCP_MESSAGE_TYPE;
diff --git a/server/dhcp.c b/server/dhcp.c
index 7a01c3c9b..9e8398358 100644
--- a/server/dhcp.c
+++ b/server/dhcp.c
@@ -1222,6 +1222,13 @@ void dhcpinform (packet, ms_nulltp)
 		}
 	}
 
+	/*
+	 * Remove any time options, per section 3.4 RFC 2131
+	 */
+	delete_option(&dhcp_universe, options, DHO_DHCP_LEASE_TIME);
+	delete_option(&dhcp_universe, options, DHO_DHCP_RENEWAL_TIME);
+	delete_option(&dhcp_universe, options, DHO_DHCP_REBINDING_TIME);
+
 	/* Set up the option buffer... */
 	outgoing.packet_length =
 		cons_options (packet, outgoing.raw, (struct lease *)0,