5 files changed, 184 insertions, 4 deletions

diff --git a/ChangeLog b/ChangeLog
index 53d039fc3..e37d26ad7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -63,6 +63,10 @@
      [sftp.1]
      emphasise the batchmode functionality and make reference to pubkey auth,
      both of which are FAQs; ok markus@
+   - markus@cvs.openbsd.org 2003/05/14 02:15:47
+     [auth2.c monitor.c sshconnect2.c auth2-krb5.c]
+     implement kerberos over ssh2 ("kerberos-2@ssh.com"); tested with jakob@
+     server interops with commercial client; ok jakob@ djm@
 
 20030512
  - (djm) Redhat spec: Don't install profile.d scripts when not 
@@ -1450,4 +1454,4 @@
      save auth method before monitor_reset_key_state(); bugzilla bug #284;
      ok provos@
 
-$Id: ChangeLog,v 1.2691 2003/05/14 03:47:07 djm Exp $
+$Id: ChangeLog,v 1.2692 2003/05/14 03:47:37 djm Exp $
diff --git a/auth2-krb5.c b/auth2-krb5.c
new file mode 100644
index 000000000..ea4d76da0
--- /dev/null
+++ b/auth2-krb5.c
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2003 Markus Friedl.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+RCSID("$OpenBSD: auth2-krb5.c,v 1.1 2003/05/14 02:15:47 markus Exp $");
+
+#include <krb5.h>
+
+#include "ssh2.h"
+#include "xmalloc.h"
+#include "packet.h"
+#include "log.h"
+#include "auth.h"
+#include "monitor_wrap.h"
+#include "servconf.h"
+
+/* import */
+extern ServerOptions options;
+
+static int
+userauth_kerberos(Authctxt *authctxt)
+{
+        krb5_data tkt, reply;
+        char *client = NULL;
+        int authenticated = 0;
+
+        tkt.data = packet_get_string(&tkt.length);
+        packet_check_eom();
+
+        if (PRIVSEP(auth_krb5(authctxt, &tkt, &client, &reply))) {
+                authenticated = 1;
+                if (reply.length)
+                        xfree(reply.data);
+        }
+        if (client)
+                xfree(client);
+        xfree(tkt.data);
+        return (authenticated);
+}
+
+Authmethod method_kerberos = {
+        "kerberos-2@ssh.com",
+        userauth_kerberos,
+        &options.kerberos_authentication
+};
diff --git a/auth2.c b/auth2.c
index b2f14bacd..03d170e23 100644
--- a/auth2.c
+++ b/auth2.c
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: auth2.c,v 1.97 2003/04/08 20:21:28 itojun Exp $");
+RCSID("$OpenBSD: auth2.c,v 1.98 2003/05/14 02:15:47 markus Exp $");
 
 #include "ssh2.h"
 #include "xmalloc.h"
@@ -50,6 +50,9 @@ extern Authmethod method_pubkey;
 extern Authmethod method_passwd;
 extern Authmethod method_kbdint;
 extern Authmethod method_hostbased;
+#ifdef KRB5
+extern Authmethod method_kerberos;
+#endif
 
 Authmethod *authmethods[] = {
         &method_none,
@@ -57,6 +60,9 @@ Authmethod *authmethods[] = {
         &method_passwd,
         &method_kbdint,
         &method_hostbased,
+#ifdef KRB5
+        &method_kerberos,
+#endif
         NULL
 };
 
diff --git a/monitor.c b/monitor.c
index 1f6677581..78d1e2e0c 100644
--- a/monitor.c
+++ b/monitor.c
@@ -25,7 +25,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: monitor.c,v 1.38 2003/04/08 20:21:28 itojun Exp $");
+RCSID("$OpenBSD: monitor.c,v 1.39 2003/05/14 02:15:47 markus Exp $");
 
 #include <openssl/dh.h>
 
@@ -182,6 +182,9 @@ struct mon_table mon_dispatch_proto20[] = {
 #endif
     {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed},
     {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify},
+#ifdef KRB5
+    {MONITOR_REQ_KRB5, MON_ONCE|MON_AUTH, mm_answer_krb5},
+#endif
     {0, 0, NULL}
 };
 
@@ -1483,6 +1486,8 @@ mm_answer_krb5(int socket, Buffer *m)
         }
         mm_request_send(socket, MONITOR_ANS_KRB5, m);
 
+        auth_method = "kerberos";
+
         return success;
 }
 #endif
diff --git a/sshconnect2.c b/sshconnect2.c
index 74d699ff2..0605e4e5f 100644
--- a/sshconnect2.c
+++ b/sshconnect2.c
@@ -23,7 +23,11 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshconnect2.c,v 1.117 2003/05/12 16:55:37 markus Exp $");
+RCSID("$OpenBSD: sshconnect2.c,v 1.118 2003/05/14 02:15:47 markus Exp $");
+
+#ifdef KRB5
+#include <krb5.h>
+#endif
 
 #include "ssh.h"
 #include "ssh2.h"
@@ -190,6 +194,7 @@ int	userauth_pubkey(Authctxt *);
 int     userauth_passwd(Authctxt *);
 int     userauth_kbdint(Authctxt *);
 int     userauth_hostbased(Authctxt *);
+int     userauth_kerberos(Authctxt *);
 
 void    userauth(Authctxt *, char *);
 
@@ -208,6 +213,12 @@ Authmethod authmethods[] = {
                 userauth_hostbased,
                 &options.hostbased_authentication,
                 NULL},
+#if KRB5
+        {"kerberos-2@ssh.com",
+                userauth_kerberos,
+                &options.kerberos_authentication,
+                NULL},
+#endif
         {"publickey",
                 userauth_pubkey,
                 &options.pubkey_authentication,
@@ -1112,6 +1123,94 @@ userauth_hostbased(Authctxt *authctxt)
         return 1;
 }
 
+#if KRB5
+static int
+ssh_krb5_helper(krb5_data *ap)
+{
+        krb5_context xcontext = NULL;   /* XXX share with ssh1 */
+        krb5_auth_context xauth_context = NULL;
+
+        krb5_context *context;
+        krb5_auth_context *auth_context;
+        krb5_error_code problem;
+        const char *tkfile;
+        struct stat buf;
+        krb5_ccache ccache = NULL;
+        const char *remotehost;
+        int ret;
+
+        memset(ap, 0, sizeof(*ap));
+
+        context = &xcontext;
+        auth_context = &xauth_context;
+
+        problem = krb5_init_context(context);
+        if (problem) {
+                debug("Kerberos v5: krb5_init_context failed");
+                ret = 0;
+                goto out;
+        }
+
+        tkfile = krb5_cc_default_name(*context);
+        if (strncmp(tkfile, "FILE:", 5) == 0)
+                tkfile += 5;
+
+        if (stat(tkfile, &buf) == 0 && getuid() != buf.st_uid) {
+                debug("Kerberos v5: could not get default ccache (permission denied).");
+                ret = 0;
+                goto out;
+        }
+
+        problem = krb5_cc_default(*context, &ccache);
+        if (problem) {
+                debug("Kerberos v5: krb5_cc_default failed: %s",
+                    krb5_get_err_text(*context, problem));
+                ret = 0;
+                goto out;
+        }
+
+        remotehost = get_canonical_hostname(1);
+
+        problem = krb5_mk_req(*context, auth_context, AP_OPTS_MUTUAL_REQUIRED,
+            "host", remotehost, NULL, ccache, ap);
+        if (problem) {
+                debug("Kerberos v5: krb5_mk_req failed: %s",
+                    krb5_get_err_text(*context, problem));
+                ret = 0;
+                goto out;
+        }
+        ret = 1;
+
+ out:
+        if (ccache != NULL)
+                krb5_cc_close(*context, ccache);
+        if (*auth_context)
+                krb5_auth_con_free(*context, *auth_context);
+        if (*context)
+                krb5_free_context(*context);
+        return (ret);
+}
+
+int
+userauth_kerberos(Authctxt *authctxt)
+{
+        krb5_data ap;
+
+        if (ssh_krb5_helper(&ap) == 0)
+                return (0);
+
+        packet_start(SSH2_MSG_USERAUTH_REQUEST);
+        packet_put_cstring(authctxt->server_user);
+        packet_put_cstring(authctxt->service);
+        packet_put_cstring(authctxt->method->name);
+        packet_put_string(ap.data, ap.length);
+        packet_send();
+
+        krb5_data_free(&ap);
+        return (1);
+}
+#endif
+
 /* find auth method */
 
 /*