crypto/external/bsd/openssh/dist/gss-serv-krb5.c

   1 /*      $NetBSD$        */
   2 /* $OpenBSD: gss-serv-krb5.c,v 1.7 2006/08/03 03:34:42 deraadt Exp $ */
   3
   4 /*
   5  * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #include "includes.h"
  29 __RCSID("$NetBSD: gss-serv-krb5.c,v 1.4 2006/09/28 21:22:14 christos Exp $");
  30 #ifdef GSSAPI
  31 #ifdef KRB5
  32
  33 #include <sys/types.h>
  34
  35 #include <stdarg.h>
  36 #include <string.h>
  37
  38 #include "xmalloc.h"
  39 #include "key.h"
  40 #include "hostfile.h"
  41 #include "auth.h"
  42 #include "log.h"
  43
  44 #include "buffer.h"
  45 #include "servconf.h"
  46 #include "ssh-gss.h"
  47
  48 extern ServerOptions options;
  49
  50 #ifdef HEIMDAL
  51 # include <krb5.h>
  52 #else
  53 # ifdef HAVE_GSSAPI_KRB5_H
  54 #  include <gssapi_krb5.h>
  55 # elif HAVE_GSSAPI_GSSAPI_KRB5_H
  56 #  include <gssapi/gssapi_krb5.h>
  57 # endif
  58 #endif
  59
  60 static krb5_context krb_context = NULL;
  61
  62 /* Initialise the krb5 library, for the stuff that GSSAPI won't do */
  63
  64 static int
  65 ssh_gssapi_krb5_init(void)
  66 {
  67         krb5_error_code problem;
  68
  69         if (krb_context != NULL)
  70                 return 1;
  71
  72         problem = krb5_init_context(&krb_context);
  73         if (problem) {
  74                 logit("Cannot initialize krb5 context");
  75                 return 0;
  76         }
  77 #ifdef isneeded
  78         krb5_init_ets(krb_context);
  79 #endif
  80
  81         return 1;
  82 }
  83
  84 /* Check if this user is OK to login. This only works with krb5 - other
  85  * GSSAPI mechanisms will need their own.
  86  * Returns true if the user is OK to log in, otherwise returns 0
  87  */
  88
  89 static int
  90 ssh_gssapi_krb5_userok(ssh_gssapi_client *client, char *name)
  91 {
  92         krb5_principal princ;
  93         int retval;
  94
  95         if (ssh_gssapi_krb5_init() == 0)
  96                 return 0;
  97
  98         if ((retval = krb5_parse_name(krb_context, client->exportedname.value,
  99             &princ))) {
 100                 logit("krb5_parse_name(): %.100s",
 101                     krb5_get_err_text(krb_context, retval));
 102                 return 0;
 103         }
 104         if (krb5_kuserok(krb_context, princ, name)) {
 105                 retval = 1;
 106                 logit("Authorized to %s, krb5 principal %s (krb5_kuserok)",
 107                     name, (char *)client->displayname.value);
 108         } else
 109                 retval = 0;
 110
 111         krb5_free_principal(krb_context, princ);
 112         return retval;
 113 }
 114
 115
 116 /* This writes out any forwarded credentials from the structure populated
 117  * during userauth. Called after we have setuid to the user */
 118
 119 static void
 120 ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
 121 {
 122         krb5_ccache ccache;
 123         krb5_error_code problem;
 124         krb5_principal princ;
 125         OM_uint32 maj_status, min_status;
 126         int len;
 127
 128         if (client->creds == NULL) {
 129                 debug("No credentials stored");
 130                 return;
 131         }
 132
 133         if (ssh_gssapi_krb5_init() == 0)
 134                 return;
 135
 136 #ifdef HEIMDAL
 137         if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) {
 138                 logit("krb5_cc_gen_new(): %.100s",
 139                     krb5_get_err_text(krb_context, problem));
 140                 return;
 141         }
 142 #else
 143         if ((problem = ssh_krb5_cc_gen(krb_context, &ccache))) {
 144                 logit("ssh_krb5_cc_gen(): %.100s",
 145                     krb5_get_err_text(krb_context, problem));
 146                 return;
 147         }
 148 #endif  /* #ifdef HEIMDAL */
 149
 150         if ((problem = krb5_parse_name(krb_context,
 151             client->exportedname.value, &princ))) {
 152                 logit("krb5_parse_name(): %.100s",
 153                     krb5_get_err_text(krb_context, problem));
 154                 krb5_cc_destroy(krb_context, ccache);
 155                 return;
 156         }
 157
 158         if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) {
 159                 logit("krb5_cc_initialize(): %.100s",
 160                     krb5_get_err_text(krb_context, problem));
 161                 krb5_free_principal(krb_context, princ);
 162                 krb5_cc_destroy(krb_context, ccache);
 163                 return;
 164         }
 165
 166         krb5_free_principal(krb_context, princ);
 167
 168         if ((maj_status = gss_krb5_copy_ccache(&min_status,
 169             client->creds, ccache))) {
 170                 logit("gss_krb5_copy_ccache() failed");
 171                 krb5_cc_destroy(krb_context, ccache);
 172                 return;
 173         }
 174
 175         client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache));
 176         client->store.envvar = "KRB5CCNAME";
 177         len = strlen(client->store.filename) + 6;
 178         client->store.envval = xmalloc(len);
 179         snprintf(client->store.envval, len, "FILE:%s", client->store.filename);
 180
 181 #ifdef USE_PAM
 182         if (options.use_pam)
 183                 do_pam_putenv(client->store.envvar, client->store.envval);
 184 #endif
 185
 186         krb5_cc_close(krb_context, ccache);
 187
 188         return;
 189 }
 190
 191 ssh_gssapi_mech gssapi_kerberos_mech = {
 192         "toWM5Slw5Ew8Mqkay+al2g==",
 193         "Kerberos",
 194         {9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"},
 195         NULL,
 196         &ssh_gssapi_krb5_userok,
 197         NULL,
 198         &ssh_gssapi_krb5_storecreds
 199 };
 200
 201 #endif /* KRB5 */
 202
 203 #endif /* GSSAPI */