- markus@cvs.openbsd.org 2003/08/22 10:56:09

     [auth2.c auth2-gss.c auth.h compat.c compat.h gss-genr.c gss-serv-krb5.c
     gss-serv.c monitor.c monitor.h monitor_wrap.c monitor_wrap.h readconf.c
     readconf.h servconf.c servconf.h session.c session.h ssh-gss.h
     ssh_config.5 sshconnect2.c sshd_config sshd_config.5]
     support GSS API user authentication; patches from Simon Wilkinson,
     stripped down and tested by Jakob and myself.

1 files changed, 168 insertions, 0 deletions

diff --git a/gss-serv-krb5.c b/gss-serv-krb5.c
new file mode 100644
index 000000000..d86872258
--- /dev/null
+++ b/gss-serv-krb5.c
@@ -0,0 +1,168 @@
+/*      $OpenBSD: gss-serv-krb5.c,v 1.1 2003/08/22 10:56:09 markus Exp $        */
+
+/*
+ * Copyright (c) 2001-2003 Simon Wilkinson. 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"
+
+#ifdef GSSAPI
+#ifdef KRB5
+
+#include "auth.h"
+#include "xmalloc.h"
+#include "log.h"
+#include "servconf.h"
+
+#include "ssh-gss.h"
+
+extern ServerOptions options;
+
+#include <krb5.h>
+
+static krb5_context krb_context = NULL;
+
+/* Initialise the krb5 library, for the stuff that GSSAPI won't do */
+
+static int 
+ssh_gssapi_krb5_init()
+{
+        krb5_error_code problem;
+
+        if (krb_context != NULL)
+                return 1;
+
+        problem = krb5_init_context(&krb_context);
+        if (problem) {
+                logit("Cannot initialize krb5 context");
+                return 0;
+        }
+        krb5_init_ets(krb_context);
+
+        return 1;
+}
+
+/* Check if this user is OK to login. This only works with krb5 - other
+ * GSSAPI mechanisms will need their own.
+ * Returns true if the user is OK to log in, otherwise returns 0
+ */
+
+static int
+ssh_gssapi_krb5_userok(ssh_gssapi_client *client, char *name)
+{
+        krb5_principal princ;
+        int retval;
+
+        if (ssh_gssapi_krb5_init() == 0)
+                return 0;
+
+        if ((retval = krb5_parse_name(krb_context, client->exportedname.value,
+            &princ))) {
+                logit("krb5_parse_name(): %.100s",
+                    krb5_get_err_text(krb_context, retval));
+                return 0;
+        }
+        if (krb5_kuserok(krb_context, princ, name)) {
+                retval = 1;
+                logit("Authorized to %s, krb5 principal %s (krb5_kuserok)",
+                    name, (char *)client->displayname.value);
+        } else
+                retval = 0;
+
+        krb5_free_principal(krb_context, princ);
+        return retval;
+}
+
+
+/* This writes out any forwarded credentials from the structure populated
+ * during userauth. Called after we have setuid to the user */
+
+static void
+ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
+{
+        krb5_ccache ccache;
+        krb5_error_code problem;
+        krb5_principal princ;
+        OM_uint32 maj_status, min_status;
+
+        if (client->creds == NULL) {
+                debug("No credentials stored");
+                return;
+        }
+
+        if (ssh_gssapi_krb5_init() == 0)
+                return;
+
+        if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) {
+                logit("krb5_cc_gen_new(): %.100s",
+                    krb5_get_err_text(krb_context, problem));
+                return;
+        }
+
+        if ((problem = krb5_parse_name(krb_context, 
+            client->exportedname.value, &princ))) {
+                logit("krb5_parse_name(): %.100s",
+                    krb5_get_err_text(krb_context, problem));
+                krb5_cc_destroy(krb_context, ccache);
+                return;
+        }
+
+        if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) {
+                logit("krb5_cc_initialize(): %.100s",
+                    krb5_get_err_text(krb_context, problem));
+                krb5_free_principal(krb_context, princ);
+                krb5_cc_destroy(krb_context, ccache);
+                return;
+        }
+
+        krb5_free_principal(krb_context, princ);
+
+        if ((maj_status = gss_krb5_copy_ccache(&min_status, 
+            client->creds, ccache))) {
+                logit("gss_krb5_copy_ccache() failed");
+                krb5_cc_destroy(krb_context, ccache);
+                return;
+        }
+
+        client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache));
+        client->store.envvar = "KRB5CCNAME";
+        client->store.envval = xstrdup(client->store.filename);
+
+        krb5_cc_close(krb_context, ccache);
+
+        return;
+}
+
+ssh_gssapi_mech gssapi_kerberos_mech = {
+        "toWM5Slw5Ew8Mqkay+al2g==",
+        "Kerberos",
+        {9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"},
+        NULL,
+        &ssh_gssapi_krb5_userok,
+        NULL,
+        &ssh_gssapi_krb5_storecreds
+};
+
+#endif /* KRB5 */
+
+#endif /* GSSAPI */