Merge Athena changes for requiring encrypted connections

ticket: 841
tags: pullup

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@16866 dc483132-0cff-0310-8789-dd5450dbe970

8 files changed, 149 insertions, 30 deletions

diff --git a/src/appl/telnet/libtelnet/ChangeLog b/src/appl/telnet/libtelnet/ChangeLog
index 9e5c888d7..3467422dd 100644
--- a/src/appl/telnet/libtelnet/ChangeLog
+++ b/src/appl/telnet/libtelnet/ChangeLog
@@ -1,3 +1,8 @@
+2004-11-15  Tom Yu  <tlyu@mit.edu>
+
+	* auth-proto.h, auth.c: Merge Athena changes for requiring
+	encrypted connections.
+
 2004-06-04  Ken Raeburn  <raeburn@mit.edu>
 
 	* Makefile.in (LIBBASE): Renamed from LIB.
diff --git a/src/appl/telnet/libtelnet/auth-proto.h b/src/appl/telnet/libtelnet/auth-proto.h
index 68cae7efc..6b4957032 100644
--- a/src/appl/telnet/libtelnet/auth-proto.h
+++ b/src/appl/telnet/libtelnet/auth-proto.h
@@ -67,7 +67,8 @@ void auth_send_retry (void);
 void auth_is (unsigned char *, int);
 void auth_reply (unsigned char *, int);
 void auth_finished (Authenticator *, int);
-int auth_wait (char *);
+void auth_wait (char *);
+int auth_check (char *);
 int auth_must_encrypt (void);
 void auth_disable_name (char *);
 void auth_gen_printsub (unsigned char *, int, unsigned char *, unsigned int);
diff --git a/src/appl/telnet/libtelnet/auth.c b/src/appl/telnet/libtelnet/auth.c
index 9c1b0b0fc..28b8ae8d1 100644
--- a/src/appl/telnet/libtelnet/auth.c
+++ b/src/appl/telnet/libtelnet/auth.c
@@ -85,6 +85,7 @@
 int auth_debug_mode = 0;
 int auth_has_failed = 0;
 int auth_enable_encrypt = 0;
+int auth_client_non_unix = 0;
 static 	char	*Name = "Noname";
 static	int	Server = 0;
 static	Authenticator	*authenticated = 0;
@@ -337,15 +338,28 @@ auth_request()
 		authenticating = 1;
 		while (ap->type) {
 			if (i_support & ~i_wont_support & typemask(ap->type)) {
-				if (auth_debug_mode) {
-					printf(">>>%s: Sending type %d %d\r\n",
-						Name, ap->type, ap->way);
+				if (ap->type == AUTHTYPE_KERBEROS_V4 ||
+				    !auth_client_non_unix) {
+					if (auth_debug_mode) {
+						printf(">>>%s: Sending type %d %d\r\n",
+						       Name, ap->type, ap->way);
+					}
+					*e++ = ap->type;
+					*e++ = ap->way;
 				}
-				*e++ = ap->type;
-				*e++ = ap->way;
 			}
 			++ap;
 		}
+		if (auth_client_non_unix) {
+			ap = authenticators;
+			while (ap->type) {
+				if (i_support & ~i_wont_support & typemask(ap->type)) {
+					*e++ = ap->type;
+					*e++ = ap->way;
+				}
+				++ap;
+			}
+		}
 		*e++ = IAC;
 		*e++ = SE;
 		net_write(str_request, e - str_request);
@@ -562,7 +576,7 @@ auth_intr(sig)
 	auth_finished(0, AUTH_REJECT);
 }
 
-	int
+	void
 auth_wait(name)
 	char *name;
 {
@@ -570,7 +584,7 @@ auth_wait(name)
 		printf(">>>%s: in auth_wait.\r\n", Name);
 
 	if (Server && !authenticating)
-		return(0);
+		return;
 
 	(void) signal(SIGALRM, auth_intr);
 	alarm(30);
@@ -579,7 +593,12 @@ auth_wait(name)
 			break;
 	alarm(0);
 	(void) signal(SIGALRM, SIG_DFL);
+}
 
+	int
+auth_check(name)
+	char *name;
+{
 	/*
 	 * Now check to see if the user is valid or not
 	 */
diff --git a/src/appl/telnet/telnetd/ChangeLog b/src/appl/telnet/telnetd/ChangeLog
index 1902a32f7..760cbb23f 100644
--- a/src/appl/telnet/telnetd/ChangeLog
+++ b/src/appl/telnet/telnetd/ChangeLog
@@ -1,3 +1,15 @@
+2004-11-15  Tom Yu  <tlyu@mit.edu>
+
+	* ext.h: New variable "must_encrypt".
+
+	* telnetd.8: Update for changed command-line options.
+
+	* telnetd.c (getterminaltype): Merge Athena changes to require
+	encrypted connections.
+
+	* utility.c (ttsuck): Merge Athena changes to work around some
+	client timing bugs.
+
 2004-09-22  Tom Yu  <tlyu@mit.edu>
 
 	* Makefile.in (telnetd): Use UTIL_LIB.
diff --git a/src/appl/telnet/telnetd/ext.h b/src/appl/telnet/telnetd/ext.h
index 9fe38ef8b..7b77a44b0 100644
--- a/src/appl/telnet/telnetd/ext.h
+++ b/src/appl/telnet/telnetd/ext.h
@@ -88,6 +88,10 @@ extern char *unptyip;  /* pointer to remaining characters in buffer */
 extern int	pty, net;
 extern int	SYNCHing;		/* we are in TELNET SYNCH mode */
 
+#ifdef ENCRYPTION
+extern int	must_encrypt;
+#endif
+
 extern void
 	_termstat (void),
 	add_slc (int, int, int),
diff --git a/src/appl/telnet/telnetd/telnetd.8 b/src/appl/telnet/telnetd/telnetd.8
index 9426a0c3b..78700cbed 100644
--- a/src/appl/telnet/telnetd/telnetd.8
+++ b/src/appl/telnet/telnetd/telnetd.8
@@ -39,7 +39,7 @@ protocol server
 .SH SYNOPSIS
 .B /usr/libexec/telnetd
 [\fB\-a\fP \fIauthmode\fP] [\fB\-B\fP] [\fB\-D\fP] [\fIdebugmode\fP]
-[\fB\-edebug\fP] [\fB\-h\fP] [\fB\-I\fP\fIinitid\fP] [\fB\-l\fP]
+[\fB\-e\fP] [\fB\-h\fP] [\fB\-I\fP\fIinitid\fP] [\fB\-l\fP]
 [\fB\-k\fP] [\fB\-n\fP] [\fB\-r\fP\fIlowpty-highpty\fP] [\fB\-s\fP]
 [\fB\-S\fP \fItos\fP] [\fB\-U\fP] [\fB\-X\fP \fIauthtype\fP]
 [\fB\-w\fP [\fBip\fP|\fImaxhostlen\fP[\fB,\fP[\fBno\fP]\fBstriplocal\fP]]]
@@ -163,6 +163,9 @@ Displays the data stream received by
 .B ptydata
 Displays data written to the pty.
 .TP
+.B encrypt
+Enables	encryption debugging code.
+.TP
 .B exercise
 Has not been implemented yet.
 .RE
@@ -175,12 +178,10 @@ Enables debugging on each socket created by
 in
 .IR socket (2)).
 .TP
-.B \-edebug
-If
+.B \-e
+This option causes
 .B telnetd
-has been compiled with support for data encryption, then the
-.B edebug
-option may be used to enable encryption debugging code.
+to refuse unencrypted connections.
 .TP
 .B \-h
 Disables the printing of host-specific information before login has been
diff --git a/src/appl/telnet/telnetd/telnetd.c b/src/appl/telnet/telnetd/telnetd.c
index 5633d5625..a90fa5c5c 100644
--- a/src/appl/telnet/telnetd/telnetd.c
+++ b/src/appl/telnet/telnetd/telnetd.c
@@ -173,7 +173,7 @@ char valid_opts[] = {
 	'D', ':',
 #endif
 #ifdef	ENCRYPTION
-	'e', ':',
+	'e',
 #endif
 #if	defined(CRAY) && defined(NEWINIT)
 	'I', ':',
@@ -308,6 +308,9 @@ main(argc, argv)
 				diagnostic |= TD_PTYDATA;
 			} else if (!strcmp(optarg, "options")) {
 				diagnostic |= TD_OPTIONS;
+			} else if (!strcmp(optarg, "encrypt")) {
+				extern int encrypt_debug_mode;
+				encrypt_debug_mode = 1;
 			} else {
 				usage();
 				/* NOT REACHED */
@@ -317,13 +320,7 @@ main(argc, argv)
 
 #ifdef	ENCRYPTION
 		case 'e':
-			if (strcmp(optarg, "debug") == 0) {
-				extern int encrypt_debug_mode;
-				encrypt_debug_mode = 1;
-				break;
-			}
-			usage();
-			/* NOTREACHED */
+			must_encrypt = 1;
 			break;
 #endif	/* ENCRYPTION */
 
@@ -694,8 +691,12 @@ usage()
 
 static void encrypt_failure()
 {
-    char *lerror_message =
-	"Encryption was not successfully negotiated.  Goodbye.\r\n\r\n";
+    char *lerror_message;
+
+    if (auth_must_encrypt())
+	lerror_message = "Encryption was not successfully negotiated.  Goodbye.\r\n\r\n";
+    else
+	lerror_message = "Unencrypted connection refused. Goodbye.\r\n\r\n";
 
     netputs(lerror_message);
     netflush();
@@ -720,6 +721,7 @@ getterminaltype(name)
 
     settimer(baseline);
 #if	defined(AUTHENTICATION)
+    ttsuck();
     /*
      * Handle the Authentication option before we do anything else.
      */
@@ -727,7 +729,7 @@ getterminaltype(name)
     while (his_will_wont_is_changing(TELOPT_AUTHENTICATION))
 	ttloop();
     if (his_state_is_will(TELOPT_AUTHENTICATION)) {
-	retval = auth_wait(name);
+	auth_wait(name);
     }
 #endif
 
@@ -760,15 +762,25 @@ getterminaltype(name)
     if (his_state_is_will(TELOPT_ENCRYPT)) {
 	encrypt_wait();
     }
-    if (auth_must_encrypt()) {
+    if (must_encrypt || auth_must_encrypt()) {
 	time_t timeout = time(0) + 60;
 	
 	if (my_state_is_dont(TELOPT_ENCRYPT) ||
-	    my_state_is_wont(TELOPT_ENCRYPT))
+	    my_state_is_wont(TELOPT_ENCRYPT) ||
+	    his_state_is_wont(TELOPT_AUTHENTICATION))
 	    encrypt_failure();
 
-	if (!EncryptStartInput() || !EncryptStartOutput())
-	    encrypt_failure();
+	while (!EncryptStartInput()) {
+	    if (time (0) > timeout)
+		encrypt_failure();
+	    ttloop();
+	}
+
+	while (!EncryptStartOutput()) {
+	    if (time (0) > timeout)
+		encrypt_failure();
+	    ttloop();
+	}
 
 	while (!encrypt_is_encrypting()) {
 	    if (time(0) > timeout)
@@ -865,7 +877,11 @@ getterminaltype(name)
 	    }
 	}
     }
-    return(retval);
+#ifdef AUTHENTICATION
+    return(auth_check(name));
+#else
+    return(-1);
+#endif
 }  /* end of getterminaltype */
 
 static void
diff --git a/src/appl/telnet/telnetd/utility.c b/src/appl/telnet/telnetd/utility.c
index fc8ff7601..f4568ec28 100644
--- a/src/appl/telnet/telnetd/utility.c
+++ b/src/appl/telnet/telnetd/utility.c
@@ -90,6 +90,67 @@ read_again:
     }
 }  /* end of ttloop */
 
+/* 
+ * ttsuck - This is a horrible kludge to deal with a bug in
+ * HostExplorer. HostExplorer thinks it knows how to do krb5 auth, but
+ * it doesn't really. So if you offer it krb5 as an auth choice before
+ * krb4, it will sabotage the connection. So we peek ahead into the
+ * input stream to see if the client is a UNIX client, and then
+ * (later) offer krb5 first only if it is. Since no Mac/PC telnet
+ * clients do auto switching between krb4 and krb5 like the UNIX
+ * client does, it doesn't matter what order they see the choices in
+ * (except for HostExplorer).
+ *
+ * It is actually not possible to do this without looking ahead into
+ * the input stream: the client and server both try to begin
+ * auth/encryption negotiation as soon as possible, so if we let the
+ * server process things normally, it will already have sent the list
+ * of supported auth types before seeing the NEW-ENVIRON option. If
+ * you change the code to hold off sending the list of supported auth
+ * types until after it knows whether or not the remote side supports
+ * NEW-ENVIRON, then the auth negotiation and encryption negotiation
+ * race conditions won't interact properly, and encryption negotiation
+ * will reliably fail.
+ */
+
+    void
+ttsuck()
+{
+    extern int auth_client_non_unix;
+    int nread;
+    struct timeval tv;
+    fd_set fds;
+    char *p, match[] = {IAC, WILL, TELOPT_NEW_ENVIRON};
+
+    if (nfrontp-nbackp) {
+	netflush();
+    }
+    tv.tv_sec = 1;
+    tv.tv_usec = 0;
+    FD_SET(net, &fds);
+
+    while (select(net + 1, &fds, NULL, NULL, &tv) == 1)
+      {
+	nread = read(net, netibuf + ncc, sizeof(netibuf) - ncc);
+	if (nread <= 0)
+	  break;
+	ncc += nread;
+      }
+
+    auth_client_non_unix = 1;
+    for (p = netibuf; p < netibuf + ncc; p++)
+      {
+	if (!memcmp(p, match, sizeof(match)))
+	  {
+	    auth_client_non_unix = 0;
+	    break;
+	  }
+      }
+
+    if (ncc > 0)
+      telrcv();
+}
+
 /*
  * Check a descriptor to see if out of band data exists on it.
  */