1 /* $NetBSD: auth-krb5.c,v 1.5 2013/11/08 19:18:24 christos Exp $ */ 2 /* $OpenBSD: auth-krb5.c,v 1.20 2013/07/20 01:55:13 djm Exp $ */ 3 /* 4 * Kerberos v5 authentication and ticket-passing routines. 5 * 6 * $FreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp $ 7 */ 8 /* 9 * Copyright (c) 2002 Daniel Kouril. All rights reserved. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 23 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include "includes.h" 33 __RCSID("$NetBSD: auth-krb5.c,v 1.5 2013/11/08 19:18:24 christos Exp $"); 34 #include <sys/types.h> 35 #include <pwd.h> 36 #include <stdarg.h> 37 #include <string.h> 38 39 #include "xmalloc.h" 40 #include "ssh.h" 41 #include "ssh1.h" 42 #include "packet.h" 43 #include "log.h" 44 #include "buffer.h" 45 #include "servconf.h" 46 #include "uidswap.h" 47 #include "key.h" 48 #include "hostfile.h" 49 #include "auth.h" 50 51 #ifdef KRB5 52 #include <krb5.h> 53 54 extern ServerOptions options; 55 56 static int 57 krb5_init(void *context) 58 { 59 Authctxt *authctxt = (Authctxt *)context; 60 krb5_error_code problem; 61 62 if (authctxt->krb5_ctx == NULL) { 63 problem = krb5_init_context(&authctxt->krb5_ctx); 64 if (problem) 65 return (problem); 66 krb5_init_ets(authctxt->krb5_ctx); 67 } 68 return (0); 69 } 70 71 /* 72 * Try krb5 authentication. server_user is passed for logging purposes 73 * only, in auth is received ticket, in client is returned principal 74 * from the ticket 75 */ 76 int 77 auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client, krb5_data *reply) 78 { 79 krb5_error_code problem; 80 krb5_principal server; 81 krb5_ticket *ticket; 82 int fd, ret; 83 const char *errtxt; 84 85 ret = 0; 86 server = NULL; 87 ticket = NULL; 88 reply->length = 0; 89 90 problem = krb5_init(authctxt); 91 if (problem) 92 goto err; 93 94 problem = krb5_auth_con_init(authctxt->krb5_ctx, 95 &authctxt->krb5_auth_ctx); 96 if (problem) 97 goto err; 98 99 fd = packet_get_connection_in(); 100 problem = krb5_auth_con_setaddrs_from_fd(authctxt->krb5_ctx, 101 authctxt->krb5_auth_ctx, &fd); 102 if (problem) 103 goto err; 104 105 problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL, 106 KRB5_NT_SRV_HST, &server); 107 if (problem) 108 goto err; 109 110 problem = krb5_rd_req(authctxt->krb5_ctx, &authctxt->krb5_auth_ctx, 111 auth, server, NULL, NULL, &ticket); 112 if (problem) 113 goto err; 114 115 problem = krb5_copy_principal(authctxt->krb5_ctx, ticket->client, 116 &authctxt->krb5_user); 117 if (problem) 118 goto err; 119 120 /* if client wants mutual auth */ 121 problem = krb5_mk_rep(authctxt->krb5_ctx, authctxt->krb5_auth_ctx, 122 reply); 123 if (problem) 124 goto err; 125 126 /* Check .k5login authorization now. */ 127 if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user, 128 authctxt->pw->pw_name)) 129 goto err; 130 131 if (client) 132 krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user, 133 client); 134 135 ret = 1; 136 err: 137 if (server) 138 krb5_free_principal(authctxt->krb5_ctx, server); 139 if (ticket) 140 krb5_free_ticket(authctxt->krb5_ctx, ticket); 141 if (!ret && reply->length) { 142 free(reply->data); 143 memset(reply, 0, sizeof(*reply)); 144 } 145 146 if (problem) { 147 errtxt = NULL; 148 if (authctxt->krb5_ctx != NULL) 149 errtxt = krb5_get_error_message(authctxt->krb5_ctx, 150 problem); 151 if (errtxt != NULL) { 152 debug("Kerberos v5 authentication failed: %s", errtxt); 153 krb5_free_error_message(authctxt->krb5_ctx, errtxt); 154 } else 155 debug("Kerberos v5 authentication failed: %d", 156 problem); 157 } 158 159 return (ret); 160 } 161 162 int 163 auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt) 164 { 165 krb5_error_code problem; 166 krb5_ccache ccache = NULL; 167 char *pname; 168 const char *errtxt; 169 170 if (authctxt->pw == NULL || authctxt->krb5_user == NULL) 171 return (0); 172 173 temporarily_use_uid(authctxt->pw); 174 175 problem = krb5_cc_new_unique(authctxt->krb5_ctx, "FILE", NULL, &ccache); 176 if (problem) 177 goto fail; 178 179 problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache, 180 authctxt->krb5_user); 181 if (problem) 182 goto fail; 183 184 problem = krb5_rd_cred2(authctxt->krb5_ctx, authctxt->krb5_auth_ctx, 185 ccache, tgt); 186 if (problem) 187 goto fail; 188 189 authctxt->krb5_fwd_ccache = ccache; 190 ccache = NULL; 191 192 authctxt->krb5_ticket_file = __UNCONST(krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache)); 193 194 problem = krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user, 195 &pname); 196 if (problem) 197 goto fail; 198 199 #ifdef USE_PAM 200 if (options.use_pam) 201 do_pam_putenv(__UNCONST("KRB5CCNAME"), authctxt->krb5_ticket_file); 202 #endif 203 debug("Kerberos v5 TGT accepted (%s)", pname); 204 205 restore_uid(); 206 207 return (1); 208 209 fail: 210 if (problem) { 211 errtxt = krb5_get_error_message(authctxt->krb5_ctx, problem); 212 if (errtxt != NULL) { 213 debug("Kerberos v5 TGT passing failed: %s", errtxt); 214 krb5_free_error_message(authctxt->krb5_ctx, errtxt); 215 } else 216 debug("Kerberos v5 TGT passing failed: %d", problem); 217 } 218 if (ccache) 219 krb5_cc_destroy(authctxt->krb5_ctx, ccache); 220 221 restore_uid(); 222 223 return (0); 224 } 225 226 227 int 228 auth_krb5_password(Authctxt *authctxt, const char *password) 229 { 230 krb5_error_code problem; 231 krb5_ccache ccache = NULL; 232 const char *errmsg; 233 234 temporarily_use_uid(authctxt->pw); 235 236 problem = krb5_init(authctxt); 237 if (problem) 238 goto out; 239 240 problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name, 241 &authctxt->krb5_user); 242 if (problem) 243 goto out; 244 245 problem = krb5_cc_new_unique(authctxt->krb5_ctx, 246 krb5_mcc_ops.prefix, NULL, &ccache); 247 if (problem) 248 goto out; 249 250 problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache, 251 authctxt->krb5_user); 252 if (problem) 253 goto out; 254 255 restore_uid(); 256 257 problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user, 258 ccache, password, 1, NULL); 259 260 temporarily_use_uid(authctxt->pw); 261 262 if (problem) 263 goto out; 264 265 problem = krb5_cc_new_unique(authctxt->krb5_ctx, 266 krb5_fcc_ops.prefix, NULL, &authctxt->krb5_fwd_ccache); 267 if (problem) 268 goto out; 269 270 problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache, 271 authctxt->krb5_fwd_ccache); 272 krb5_cc_destroy(authctxt->krb5_ctx, ccache); 273 ccache = NULL; 274 if (problem) 275 goto out; 276 277 authctxt->krb5_ticket_file = __UNCONST(krb5_cc_get_name( 278 authctxt->krb5_ctx, authctxt->krb5_fwd_ccache)); 279 280 out: 281 restore_uid(); 282 283 if (problem) { 284 if (ccache) 285 krb5_cc_destroy(authctxt->krb5_ctx, ccache); 286 287 if (authctxt->krb5_ctx != NULL) { 288 errmsg = krb5_get_error_message(authctxt->krb5_ctx, 289 problem); 290 debug("Kerberos password authentication failed: %s", 291 errmsg); 292 krb5_free_error_message(authctxt->krb5_ctx, errmsg); 293 } else 294 debug("Kerberos password authentication failed: %d", 295 problem); 296 297 krb5_cleanup_proc(authctxt); 298 299 if (options.kerberos_or_local_passwd) 300 return (-1); 301 else 302 return (0); 303 } 304 return (authctxt->valid ? 1 : 0); 305 } 306 307 void 308 krb5_cleanup_proc(Authctxt *authctxt) 309 { 310 debug("krb5_cleanup_proc called"); 311 if (authctxt->krb5_fwd_ccache) { 312 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); 313 authctxt->krb5_fwd_ccache = NULL; 314 } 315 if (authctxt->krb5_user) { 316 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user); 317 authctxt->krb5_user = NULL; 318 } 319 if (authctxt->krb5_auth_ctx) { 320 krb5_auth_con_free(authctxt->krb5_ctx, 321 authctxt->krb5_auth_ctx); 322 authctxt->krb5_auth_ctx = NULL; 323 } 324 if (authctxt->krb5_ctx) { 325 krb5_free_context(authctxt->krb5_ctx); 326 authctxt->krb5_ctx = NULL; 327 } 328 } 329 330 #endif /* KRB5 */ 331