>Number:         2127
>Category:       bin
>Synopsis:       buglet in domestic/usr.bin/telnet vs. CNAMES and ip #'s
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    bin-bug-people (Utility Bug People)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Feb 25 19:35:00 1996
>Last-Modified:
>Originator:     Michael Graff
>Organization:
flame.org:  yes, we do know everything
>Release:        25-Feb-1996 <NetBSD-current source date>
>Environment:
	
System: NetBSD packrat.flame.org 1.1A NetBSD 1.1A (PACKRAT) #1: Fri Feb 23 00:31:21 CST 1996 explorer@packrat.flame.org:/usr/src/sys/arch/i386/compile/PACKRAT i386


>Description:
Now that telnet supports the -a (authenticaton) flag and uses kerberos4,
there is a bug in the way telnet deals with hostnames and kerberos notices.
	
>How-To-Repeat:
This arrises in two ways:
	telnet 129.186.82.10
	telnet ftp

Both of these machines are darkwatch.flame.org, but the first tries
to get a rcmd.129 ticket and the second tries rcmd.ftp, which both
fail.
	
>Fix:
	
What needs to be done is as follows:
	for ip # based telnets:
		get the host name via gethostbyaddr() and use the
			name returned.  If the call fails, keep
			the numeric version and let kerberos fail.
	for telnets to CNAMEs:
		After the gethostbyname() has returned the correct
			ip #, use it as above to get the true
			name of the machine.

Here it is, as a patch to domestic/usr.bin/telnet/commands.c:

Index: commands.c
===================================================================
RCS file: /local/source/netbsd/src/domestic/usr.bin/telnet/commands.c,v
retrieving revision 1.1.1.1
diff -c -r1.1.1.1 commands.c
*** 1.1.1.1	1996/02/25 16:39:52
--- commands.c	1996/02/26 00:03:29
***************
*** 2319,2325 ****
  	if (temp != INADDR_NONE) {
  	    sin.sin_addr.s_addr = temp;
  	    sin.sin_family = AF_INET;
! 	    (void) strcpy(_hostname, hostp);
  	    hostname = _hostname;
  	} else {
  	    host = gethostbyname(hostp);
--- 2319,2329 ----
  	if (temp != INADDR_NONE) {
  	    sin.sin_addr.s_addr = temp;
  	    sin.sin_family = AF_INET;
! 	    host = gethostbyaddr((char *)&temp, sizeof(temp), AF_INET);
! 	    if (host)
! 	        strcpy(_hostname, host->h_name);
! 	    else
! 	        strcpy(_hostname, hostp);
  	    hostname = _hostname;
  	} else {
  	    host = gethostbyname(hostp);
***************
*** 2331,2339 ****
  #else	/* defined(h_addr) */
  		memmove((caddr_t)&sin.sin_addr, host->h_addr, host->h_length);
  #endif	/* defined(h_addr) */
! 		strncpy(_hostname, host->h_name, sizeof(_hostname));
! 		_hostname[sizeof(_hostname)-1] = '\0';
! 		hostname = _hostname;
  	    } else {
  		herror(hostp);
  		setuid(getuid());
--- 2335,2347 ----
  #else	/* defined(h_addr) */
  		memmove((caddr_t)&sin.sin_addr, host->h_addr, host->h_length);
  #endif	/* defined(h_addr) */
!   	        host = gethostbyaddr((char *)&sin.sin_addr,
! 				     sizeof(sin.sin_addr), AF_INET);
! 	        if (host)
! 	            strcpy(_hostname, host->h_name);
! 	        else
! 	            strcpy(_hostname, hostp);
! 	        hostname = _hostname;
  	    } else {
  		herror(hostp);
  		setuid(getuid());
>Audit-Trail:
>Unformatted: