From: Thomas Markwalder <tmark@isc.org>
Date: Thu, 20 Jun 2019 14:15:47 +0000 (-0400)
Subject: [v4_1_esv] Ignore empty host name option when parsing v4 packets
X-Git-Tag: v4_1_esv_r16b1~15
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d033337751e994a6a1bbfb64ade6460e69fed420;p=thirdparty%2Fdhcp.git

[v4_1_esv] Ignore empty host name option when parsing v4 packets

        Merges in rt43786
---

diff --git a/RELNOTES b/RELNOTES
index 4eadf7674..904566043 100644
--- a/RELNOTES
+++ b/RELNOTES
@@ -78,6 +78,12 @@ dhcp-users@lists.isc.org.
   even valid values to fail as invalid on some environments.
   [ISC-Bugs #46535]
 
+- Added to code ignore empty IPv4 host name option (code 12). While RFC 2132
+  states the option cannot be empty, some clients are apparently capable of
+  sending it. Prior to this the server was attempting to use it and store it
+  in the lease file causing issues with DDNS and so forth.
+  [ISC-bugs #43786]
+
 			Changes since 4.1-ESV-R15b1
 
 - None
diff --git a/common/options.c b/common/options.c
index cd232284e..a136cd5c5 100644
--- a/common/options.c
+++ b/common/options.c
@@ -187,6 +187,14 @@ int parse_option_buffer (options, buffer, length, universe)
 			return 0;
 		}
 
+		if (universe == &dhcp_universe && code == DHO_HOST_NAME &&
+		    len == 0) {
+			/* non-compliant clients can send it
+			* we'll just drop it and go on */
+			log_debug ("Ignoring empty DHO_HOST_NAME option");
+			option_dereference(&option, MDL);
+		}
+
 		/* If the option contains an encapsulation, parse it.   If
 		   the parse fails, or the option isn't an encapsulation (by
 		   far the most common case), or the option isn't entirely