Bug 20525

	What happens is that the domain name supplied by the server is
	copied into /etc/resolve.conf, but the trailing NUL is *also*
	"copied" -- but represented as "\000".  (For example, one might
	see

		search whistle.com\000

	in /etc/resolv.conf.)

	This causes just about anything that requires a proper domain
	name on the DHCP client machine to fail rather miserably.

Fix: Skipping the above-referenced hack, here's what Doug Ambrisko
	suggested in response to my comment that perhaps dhclient ought
	to be a little more tolerant of what it receives:

From: Doug Ambrisko <ambrisko@whistle.com>
Message-Id: <200007271838.LAA42370@whistle.com>
Subject: Re: 4.1-RC heads up on dhclient
To: David Wolfskill <dhw@whistle.com>
Date: Thu, 27 Jul 2000 11:38:39 -0700 (PDT)

David Wolfskill writes:
| Perhaps the dhclient should be fixed to be a bit more tolerant -- possibly
| in addition to anything else.  After all, I'd not expect a NUL to be a
| valid character in a domain name....  :-}

Here it is, feel free to submit this on my behalf.  I've tried it against
alpo and a good dhcp server and it appears to work.

Doug A.

In reviewing that, it occurred to me that the above could still
	break if there were multiple trailing NULs.  Granted, that's
	pathological, but this would fix that, I think (though I haven't
	tested it):



All that aside, it would probably be better to scan from the
	left side of the domain name, and stop if either "len" is
	reached or a character is read that is invalid in a domain name.--eKDxYGKTecLRw1ip3p2oFdh0ngduJL5uzASJUgVV2WIObYgi
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Index: common/options.c
===================================================================
RCS file: /cvs/freebsd/src/contrib/isc-dhcp/common/options.c,v
retrieving revision 1.1.1.3.2.1
diff -c -r1.1.1.3.2.1 options.c
*** options.c	2000/06/26 23:07:21	1.1.1.3.2.1
--- options.c	2000/07/27 18:37:23
***************
*** 492,497 ****
--- 492,499 ----
  			fmtbuf [i] = 't';
  			fmtbuf [i + 1] = 0;
  			numhunk = -2;
+ 			/* accept null-terminated string */
+ 			if(len && !dp[len-1]) len--; 
  			break;
  		      case 'I':
  		      case 'l':
How-To-Repeat: 
	Well, you need such a broken/misfeatured DHCP server, first.
	Unfortunately, the DHCP server supplied in the Whistle InterJet
	is one such:  Archie was the one who pointed out that the server
	had been modified to support certain Microsoft clients (which
	he identified, but I failed to keep a copy of that note) that
	would otherwise break.

	Once that's done, just fire up a FreeBSD box as a DHCP client.
	(Note:  It is *not* fair to hand-edit /etc/resolve.conf, and
	then issue "chflags schg /etc/resolv.conf".  This is considered
	un-sporting in the extreme; it's one of the ways I circumvent
	the problem....)

	After the multi-user boot finishes, take a look at
	/etc/resolv.conf.