bin/179931: infinite loop in rtsol(8) by sending an option with length 0

[Florian Obser]

>Number:         179931
>Category:       bin
>Synopsis:       infinite loop in rtsol(8) by sending an option with length 0
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Jun 24 17:40:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     Florian Obser
>Release:        
>Organization:
>Environment:
FreeBSD **** 9.1-RELEASE-p4 FreeBSD 9.1-RELEASE-p4 #0: Mon Jun 17 11:42:37 UTC 2013     root at amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC  amd64

>Description:
rtsol.c:
393 	#define RA_OPT_NEXT_HDR(x) (struct nd_opt_hdr *)((char *)x + \
394 	(((struct nd_opt_hdr *)x)->nd_opt_len * 8))
        [...]
398 	while (raoptp < (char *)icp + msglen) {
        [...]
546 	raoptp = (char *)RA_OPT_NEXT_HDR(raoptp);
547 	}

Found while reading the code, unless I'm missing something, raoptp will never increase if nd_opt_len == 0 and with that the loop in line 398 will never terminate.
>How-To-Repeat:

>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: