1/* $OpenBSD: auth-krb5.c,v 1.19 2006/08/03 03:34:41 deraadt Exp $ */ 2/* 3 * Kerberos v5 authentication and ticket-passing routines. 4 * 5 * $FreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp $ 6 */ 7/* 8 * Copyright (c) 2002 Daniel Kouril. All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31#include "includes.h" 32 33#include <sys/types.h> 34#include <pwd.h> 35#include <stdarg.h> 36 37#include "xmalloc.h" 38#include "ssh.h" 39#include "ssh1.h" 40#include "packet.h" 41#include "log.h" 42#include "buffer.h" 43#include "servconf.h" 44#include "uidswap.h" 45#include "key.h" 46#include "hostfile.h" 47#include "auth.h" 48 49#ifdef KRB5 50#include <errno.h> 51#include <unistd.h> 52#include <string.h> 53#include <krb5.h> 54 55extern ServerOptions options; 56 57static int 58krb5_init(void *context) 59{ 60 Authctxt *authctxt = (Authctxt *)context; 61 krb5_error_code problem; 62 63 if (authctxt->krb5_ctx == NULL) { 64 problem = krb5_init_context(&authctxt->krb5_ctx); 65 if (problem) 66 return (problem); 67 } 68 return (0); 69} 70 71int 72auth_krb5_password(Authctxt *authctxt, const char *password) 73{ 74#ifndef HEIMDAL 75 krb5_creds creds; 76 krb5_principal server; 77#endif 78 krb5_error_code problem; 79 krb5_ccache ccache = NULL; 80 int len; 81 char *client, *platform_client; 82 83 /* get platform-specific kerberos client principal name (if it exists) */ 84 platform_client = platform_krb5_get_principal_name(authctxt->pw->pw_name); 85 client = platform_client ? platform_client : authctxt->pw->pw_name; 86 87 temporarily_use_uid(authctxt->pw); 88 89 problem = krb5_init(authctxt); 90 if (problem) 91 goto out; 92 93 problem = krb5_parse_name(authctxt->krb5_ctx, client, 94 &authctxt->krb5_user); 95 if (problem) 96 goto out; 97 98#ifdef HEIMDAL 99 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache); 100 if (problem) 101 goto out; 102 103 problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache, 104 authctxt->krb5_user); 105 if (problem) 106 goto out; 107 108 restore_uid(); 109 110 problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user, 111 ccache, password, 1, NULL); 112 113 temporarily_use_uid(authctxt->pw); 114 115 if (problem) 116 goto out; 117 118 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, 119 &authctxt->krb5_fwd_ccache); 120 if (problem) 121 goto out; 122 123 problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache, 124 authctxt->krb5_fwd_ccache); 125 krb5_cc_destroy(authctxt->krb5_ctx, ccache); 126 ccache = NULL; 127 if (problem) 128 goto out; 129 130#else 131 problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds, 132 authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL); 133 if (problem) 134 goto out; 135 136 problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL, 137 KRB5_NT_SRV_HST, &server); 138 if (problem) 139 goto out; 140 141 restore_uid(); 142 problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server, 143 NULL, NULL, NULL); 144 krb5_free_principal(authctxt->krb5_ctx, server); 145 temporarily_use_uid(authctxt->pw); 146 if (problem) 147 goto out; 148 149 if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user, client)) { 150 problem = -1; 151 goto out; 152 } 153 154 problem = ssh_krb5_cc_gen(authctxt->krb5_ctx, &authctxt->krb5_fwd_ccache); 155 if (problem) 156 goto out; 157 158 problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, 159 authctxt->krb5_user); 160 if (problem) 161 goto out; 162 163 problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, 164 &creds); 165 if (problem) 166 goto out; 167#endif 168 169 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); 170 171 len = strlen(authctxt->krb5_ticket_file) + 6; 172 authctxt->krb5_ccname = xmalloc(len); 173#ifdef USE_CCAPI 174 snprintf(authctxt->krb5_ccname, len, "API:%s", 175 authctxt->krb5_ticket_file); 176#else 177 snprintf(authctxt->krb5_ccname, len, "FILE:%s", 178 authctxt->krb5_ticket_file); 179#endif 180 181#ifdef USE_PAM 182 if (options.use_pam) 183 do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname); 184#endif 185 186 out: 187 restore_uid(); 188 189 if (platform_client != NULL) 190 xfree(platform_client); 191 192 if (problem) { 193 if (ccache) 194 krb5_cc_destroy(authctxt->krb5_ctx, ccache); 195 196 if (authctxt->krb5_ctx != NULL && problem!=-1) 197 debug("Kerberos password authentication failed: %s", 198 krb5_get_err_text(authctxt->krb5_ctx, problem)); 199 else 200 debug("Kerberos password authentication failed: %d", 201 problem); 202 203 krb5_cleanup_proc(authctxt); 204 205 if (options.kerberos_or_local_passwd) 206 return (-1); 207 else 208 return (0); 209 } 210 return (authctxt->valid ? 1 : 0); 211} 212 213void 214krb5_cleanup_proc(Authctxt *authctxt) 215{ 216 debug("krb5_cleanup_proc called"); 217 if (authctxt->krb5_fwd_ccache) { 218 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); 219 authctxt->krb5_fwd_ccache = NULL; 220 } 221 if (authctxt->krb5_user) { 222 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user); 223 authctxt->krb5_user = NULL; 224 } 225 if (authctxt->krb5_ctx) { 226 krb5_free_context(authctxt->krb5_ctx); 227 authctxt->krb5_ctx = NULL; 228 } 229} 230 231#ifndef HEIMDAL 232krb5_error_code 233ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) { 234 int tmpfd, ret, oerrno; 235 char ccname[40]; 236 mode_t old_umask; 237#ifdef USE_CCAPI 238 char cctemplate[] = "API:%d:krb5cc_%d_%d"; 239 240 ret = snprintf(ccname, sizeof(ccname), 241 cctemplate, (int)geteuid(), (int)getpid(), (int)time(NULL)); 242 if (ret < 0 || (size_t)ret >= sizeof(ccname)) 243 return ENOMEM; 244 245#else 246 char cctemplate[] = "FILE:/tmp/krb5cc_%d_XXXXXXXXXX"; 247 int tmpfd; 248 249 ret = snprintf(ccname, sizeof(ccname), 250 cctemplate, geteuid()); 251 if (ret < 0 || (size_t)ret >= sizeof(ccname)) 252 return ENOMEM; 253 254 old_umask = umask(0177); 255 tmpfd = mkstemp(ccname + strlen("FILE:")); 256 oerrno = errno; 257 umask(old_umask); 258 if (tmpfd == -1) { 259 logit("mkstemp(): %.100s", strerror(oerrno)); 260 return oerrno; 261 } 262 263 if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) { 264 oerrno = errno; 265 logit("fchmod(): %.100s", strerror(oerrno)); 266 close(tmpfd); 267 return oerrno; 268 } 269 close(tmpfd); 270#endif 271 272 return (krb5_cc_resolve(ctx, ccname, ccache)); 273} 274#endif /* !HEIMDAL */ 275#endif /* KRB5 */ 276