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 55 extern ServerOptions options; 56 57 static int 58 krb5_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 71 int 72 auth_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 82 temporarily_use_uid(authctxt->pw); 83 84 problem = krb5_init(authctxt); 85 if (problem) 86 goto out; 87 88 problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name, 89 &authctxt->krb5_user); 90 if (problem) 91 goto out; 92 93 #ifdef HEIMDAL 94 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache); 95 if (problem) 96 goto out; 97 98 problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache, 99 authctxt->krb5_user); 100 if (problem) 101 goto out; 102 103 restore_uid(); 104 105 problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user, 106 ccache, password, 1, NULL); 107 108 temporarily_use_uid(authctxt->pw); 109 110 if (problem) 111 goto out; 112 113 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, 114 &authctxt->krb5_fwd_ccache); 115 if (problem) 116 goto out; 117 118 problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache, 119 authctxt->krb5_fwd_ccache); 120 krb5_cc_destroy(authctxt->krb5_ctx, ccache); 121 ccache = NULL; 122 if (problem) 123 goto out; 124 125 #else 126 problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds, 127 authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL); 128 if (problem) 129 goto out; 130 131 problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL, 132 KRB5_NT_SRV_HST, &server); 133 if (problem) 134 goto out; 135 136 restore_uid(); 137 problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server, 138 NULL, NULL, NULL); 139 krb5_free_principal(authctxt->krb5_ctx, server); 140 temporarily_use_uid(authctxt->pw); 141 if (problem) 142 goto out; 143 144 if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user, 145 authctxt->pw->pw_name)) { 146 problem = -1; 147 goto out; 148 } 149 150 problem = ssh_krb5_cc_gen(authctxt->krb5_ctx, &authctxt->krb5_fwd_ccache); 151 if (problem) 152 goto out; 153 154 problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, 155 authctxt->krb5_user); 156 if (problem) 157 goto out; 158 159 problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, 160 &creds); 161 if (problem) 162 goto out; 163 #endif 164 165 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); 166 167 len = strlen(authctxt->krb5_ticket_file) + 6; 168 authctxt->krb5_ccname = xmalloc(len); 169 snprintf(authctxt->krb5_ccname, len, "FILE:%s", 170 authctxt->krb5_ticket_file); 171 172 #ifdef USE_PAM 173 if (options.use_pam) 174 do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname); 175 #endif 176 177 out: 178 restore_uid(); 179 180 if (problem) { 181 if (ccache) 182 krb5_cc_destroy(authctxt->krb5_ctx, ccache); 183 184 if (authctxt->krb5_ctx != NULL && problem!=-1) 185 debug("Kerberos password authentication failed: %s", 186 krb5_get_err_text(authctxt->krb5_ctx, problem)); 187 else 188 debug("Kerberos password authentication failed: %d", 189 problem); 190 191 krb5_cleanup_proc(authctxt); 192 193 if (options.kerberos_or_local_passwd) 194 return (-1); 195 else 196 return (0); 197 } 198 return (authctxt->valid ? 1 : 0); 199 } 200 201 void 202 krb5_cleanup_proc(Authctxt *authctxt) 203 { 204 debug("krb5_cleanup_proc called"); 205 if (authctxt->krb5_fwd_ccache) { 206 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); 207 authctxt->krb5_fwd_ccache = NULL; 208 } 209 if (authctxt->krb5_user) { 210 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user); 211 authctxt->krb5_user = NULL; 212 } 213 if (authctxt->krb5_ctx) { 214 krb5_free_context(authctxt->krb5_ctx); 215 authctxt->krb5_ctx = NULL; 216 } 217 } 218 219 #ifndef HEIMDAL 220 krb5_error_code 221 ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) { 222 int tmpfd, ret; 223 char ccname[40]; 224 mode_t old_umask; 225 226 ret = snprintf(ccname, sizeof(ccname), 227 "FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid()); 228 if (ret < 0 || (size_t)ret >= sizeof(ccname)) 229 return ENOMEM; 230 231 old_umask = umask(0177); 232 tmpfd = mkstemp(ccname + strlen("FILE:")); 233 umask(old_umask); 234 if (tmpfd == -1) { 235 logit("mkstemp(): %.100s", strerror(errno)); 236 return errno; 237 } 238 239 if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) { 240 logit("fchmod(): %.100s", strerror(errno)); 241 close(tmpfd); 242 return errno; 243 } 244 close(tmpfd); 245 246 return (krb5_cc_resolve(ctx, ccname, ccache)); 247 } 248 #endif /* !HEIMDAL */ 249 #endif /* KRB5 */ 250