1 /* $NetBSD: gss-serv-krb5.c,v 1.2 2009/06/07 22:38:46 christos Exp $ */ 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 1.2 2009/06/07 22:38:46 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 */ 204