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 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 snprintf(authctxt->krb5_ccname, len, "FILE:%s", 174 authctxt->krb5_ticket_file); 175 176 #ifdef USE_PAM 177 if (options.use_pam) 178 do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname); 179 #endif 180 181 out: 182 restore_uid(); 183 184 if (platform_client != NULL) 185 xfree(platform_client); 186 187 if (problem) { 188 if (ccache) 189 krb5_cc_destroy(authctxt->krb5_ctx, ccache); 190 191 if (authctxt->krb5_ctx != NULL && problem!=-1) 192 debug("Kerberos password authentication failed: %s", 193 krb5_get_err_text(authctxt->krb5_ctx, problem)); 194 else 195 debug("Kerberos password authentication failed: %d", 196 problem); 197 198 krb5_cleanup_proc(authctxt); 199 200 if (options.kerberos_or_local_passwd) 201 return (-1); 202 else 203 return (0); 204 } 205 return (authctxt->valid ? 1 : 0); 206 } 207 208 void 209 krb5_cleanup_proc(Authctxt *authctxt) 210 { 211 debug("krb5_cleanup_proc called"); 212 if (authctxt->krb5_fwd_ccache) { 213 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); 214 authctxt->krb5_fwd_ccache = NULL; 215 } 216 if (authctxt->krb5_user) { 217 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user); 218 authctxt->krb5_user = NULL; 219 } 220 if (authctxt->krb5_ctx) { 221 krb5_free_context(authctxt->krb5_ctx); 222 authctxt->krb5_ctx = NULL; 223 } 224 } 225 226 #ifndef HEIMDAL 227 krb5_error_code 228 ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) { 229 int tmpfd, ret; 230 char ccname[40]; 231 mode_t old_umask; 232 233 ret = snprintf(ccname, sizeof(ccname), 234 "FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid()); 235 if (ret < 0 || (size_t)ret >= sizeof(ccname)) 236 return ENOMEM; 237 238 old_umask = umask(0177); 239 tmpfd = mkstemp(ccname + strlen("FILE:")); 240 umask(old_umask); 241 if (tmpfd == -1) { 242 logit("mkstemp(): %.100s", strerror(errno)); 243 return errno; 244 } 245 246 if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) { 247 logit("fchmod(): %.100s", strerror(errno)); 248 close(tmpfd); 249 return errno; 250 } 251 close(tmpfd); 252 253 return (krb5_cc_resolve(ctx, ccname, ccache)); 254 } 255 #endif /* !HEIMDAL */ 256 #endif /* KRB5 */ 257