1 /* 2 * Kerberos v5 authentication and ticket-passing routines. 3 * 4 * $FreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp $ 5 */ 6 /* 7 * Copyright (c) 2002 Daniel Kouril. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30 #include "includes.h" 31 RCSID("$OpenBSD: auth-krb5.c,v 1.11 2003/07/16 15:02:06 markus Exp $"); 32 33 #include "ssh.h" 34 #include "ssh1.h" 35 #include "packet.h" 36 #include "xmalloc.h" 37 #include "log.h" 38 #include "servconf.h" 39 #include "uidswap.h" 40 #include "auth.h" 41 42 #ifdef KRB5 43 #include <krb5.h> 44 45 extern ServerOptions options; 46 47 static int 48 krb5_init(void *context) 49 { 50 Authctxt *authctxt = (Authctxt *)context; 51 krb5_error_code problem; 52 static int cleanup_registered = 0; 53 54 if (authctxt->krb5_ctx == NULL) { 55 problem = krb5_init_context(&authctxt->krb5_ctx); 56 if (problem) 57 return (problem); 58 krb5_init_ets(authctxt->krb5_ctx); 59 } 60 if (!cleanup_registered) { 61 fatal_add_cleanup(krb5_cleanup_proc, authctxt); 62 cleanup_registered = 1; 63 } 64 return (0); 65 } 66 67 /* 68 * Try krb5 authentication. server_user is passed for logging purposes 69 * only, in auth is received ticket, in client is returned principal 70 * from the ticket 71 */ 72 int 73 auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client, krb5_data *reply) 74 { 75 krb5_error_code problem; 76 krb5_principal server; 77 krb5_ticket *ticket; 78 int fd, ret; 79 80 ret = 0; 81 server = NULL; 82 ticket = NULL; 83 reply->length = 0; 84 85 problem = krb5_init(authctxt); 86 if (problem) 87 goto err; 88 89 problem = krb5_auth_con_init(authctxt->krb5_ctx, 90 &authctxt->krb5_auth_ctx); 91 if (problem) 92 goto err; 93 94 fd = packet_get_connection_in(); 95 problem = krb5_auth_con_setaddrs_from_fd(authctxt->krb5_ctx, 96 authctxt->krb5_auth_ctx, &fd); 97 if (problem) 98 goto err; 99 100 problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL, 101 KRB5_NT_SRV_HST, &server); 102 if (problem) 103 goto err; 104 105 problem = krb5_rd_req(authctxt->krb5_ctx, &authctxt->krb5_auth_ctx, 106 auth, server, NULL, NULL, &ticket); 107 if (problem) 108 goto err; 109 110 problem = krb5_copy_principal(authctxt->krb5_ctx, ticket->client, 111 &authctxt->krb5_user); 112 if (problem) 113 goto err; 114 115 /* if client wants mutual auth */ 116 problem = krb5_mk_rep(authctxt->krb5_ctx, authctxt->krb5_auth_ctx, 117 reply); 118 if (problem) 119 goto err; 120 121 /* Check .k5login authorization now. */ 122 if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user, 123 authctxt->pw->pw_name)) 124 goto err; 125 126 if (client) 127 krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user, 128 client); 129 130 ret = 1; 131 err: 132 if (server) 133 krb5_free_principal(authctxt->krb5_ctx, server); 134 if (ticket) 135 krb5_free_ticket(authctxt->krb5_ctx, ticket); 136 if (!ret && reply->length) { 137 xfree(reply->data); 138 memset(reply, 0, sizeof(*reply)); 139 } 140 141 if (problem) { 142 if (authctxt->krb5_ctx != NULL) 143 debug("Kerberos v5 authentication failed: %s", 144 krb5_get_err_text(authctxt->krb5_ctx, problem)); 145 else 146 debug("Kerberos v5 authentication failed: %d", 147 problem); 148 } 149 150 return (ret); 151 } 152 153 int 154 auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt) 155 { 156 krb5_error_code problem; 157 krb5_ccache ccache = NULL; 158 char *pname; 159 160 if (authctxt->pw == NULL || authctxt->krb5_user == NULL) 161 return (0); 162 163 temporarily_use_uid(authctxt->pw); 164 165 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, &ccache); 166 if (problem) 167 goto fail; 168 169 problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache, 170 authctxt->krb5_user); 171 if (problem) 172 goto fail; 173 174 problem = krb5_rd_cred2(authctxt->krb5_ctx, authctxt->krb5_auth_ctx, 175 ccache, tgt); 176 if (problem) 177 goto fail; 178 179 authctxt->krb5_fwd_ccache = ccache; 180 ccache = NULL; 181 182 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); 183 184 problem = krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user, 185 &pname); 186 if (problem) 187 goto fail; 188 189 debug("Kerberos v5 TGT accepted (%s)", pname); 190 191 restore_uid(); 192 193 return (1); 194 195 fail: 196 if (problem) 197 debug("Kerberos v5 TGT passing failed: %s", 198 krb5_get_err_text(authctxt->krb5_ctx, problem)); 199 if (ccache) 200 krb5_cc_destroy(authctxt->krb5_ctx, ccache); 201 202 restore_uid(); 203 204 return (0); 205 } 206 207 int 208 auth_krb5_password(Authctxt *authctxt, const char *password) 209 { 210 krb5_error_code problem; 211 krb5_ccache ccache = NULL; 212 213 if (authctxt->pw == NULL) 214 return (0); 215 216 temporarily_use_uid(authctxt->pw); 217 218 problem = krb5_init(authctxt); 219 if (problem) 220 goto out; 221 222 problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name, 223 &authctxt->krb5_user); 224 if (problem) 225 goto out; 226 227 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache); 228 if (problem) 229 goto out; 230 231 problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache, 232 authctxt->krb5_user); 233 if (problem) 234 goto out; 235 236 restore_uid(); 237 238 problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user, 239 ccache, password, 1, NULL); 240 241 temporarily_use_uid(authctxt->pw); 242 243 if (problem) 244 goto out; 245 246 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, 247 &authctxt->krb5_fwd_ccache); 248 if (problem) 249 goto out; 250 251 problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache, 252 authctxt->krb5_fwd_ccache); 253 krb5_cc_destroy(authctxt->krb5_ctx, ccache); 254 ccache = NULL; 255 if (problem) 256 goto out; 257 258 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); 259 260 out: 261 restore_uid(); 262 263 if (problem) { 264 if (ccache) 265 krb5_cc_destroy(authctxt->krb5_ctx, ccache); 266 267 if (authctxt->krb5_ctx != NULL) 268 debug("Kerberos password authentication failed: %s", 269 krb5_get_err_text(authctxt->krb5_ctx, problem)); 270 else 271 debug("Kerberos password authentication failed: %d", 272 problem); 273 274 krb5_cleanup_proc(authctxt); 275 276 if (options.kerberos_or_local_passwd) 277 return (-1); 278 else 279 return (0); 280 } 281 return (1); 282 } 283 284 void 285 krb5_cleanup_proc(void *context) 286 { 287 Authctxt *authctxt = (Authctxt *)context; 288 289 debug("krb5_cleanup_proc called"); 290 if (authctxt->krb5_fwd_ccache) { 291 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); 292 authctxt->krb5_fwd_ccache = NULL; 293 } 294 if (authctxt->krb5_user) { 295 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user); 296 authctxt->krb5_user = NULL; 297 } 298 if (authctxt->krb5_auth_ctx) { 299 krb5_auth_con_free(authctxt->krb5_ctx, 300 authctxt->krb5_auth_ctx); 301 authctxt->krb5_auth_ctx = NULL; 302 } 303 if (authctxt->krb5_ctx) { 304 krb5_free_context(authctxt->krb5_ctx); 305 authctxt->krb5_ctx = NULL; 306 } 307 } 308 309 #endif /* KRB5 */ 310