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 * $xFreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp$ 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 __RCSID("$FreeBSD$"); 33 34 #include <sys/types.h> 35 #include <pwd.h> 36 #include <stdarg.h> 37 38 #include "xmalloc.h" 39 #include "ssh.h" 40 #include "ssh1.h" 41 #include "packet.h" 42 #include "log.h" 43 #include "buffer.h" 44 #include "servconf.h" 45 #include "uidswap.h" 46 #include "key.h" 47 #include "hostfile.h" 48 #include "auth.h" 49 50 #ifdef KRB5 51 #include <errno.h> 52 #include <unistd.h> 53 #include <string.h> 54 #include <krb5.h> 55 56 extern ServerOptions options; 57 58 static int 59 krb5_init(void *context) 60 { 61 Authctxt *authctxt = (Authctxt *)context; 62 krb5_error_code problem; 63 64 if (authctxt->krb5_ctx == NULL) { 65 problem = krb5_init_context(&authctxt->krb5_ctx); 66 if (problem) 67 return (problem); 68 } 69 return (0); 70 } 71 72 int 73 auth_krb5_password(Authctxt *authctxt, const char *password) 74 { 75 #ifndef HEIMDAL 76 krb5_creds creds; 77 krb5_principal server; 78 #endif 79 krb5_error_code problem; 80 krb5_ccache ccache = NULL; 81 int len; 82 83 temporarily_use_uid(authctxt->pw); 84 85 problem = krb5_init(authctxt); 86 if (problem) 87 goto out; 88 89 problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name, 90 &authctxt->krb5_user); 91 if (problem) 92 goto out; 93 94 #ifdef HEIMDAL 95 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache); 96 if (problem) 97 goto out; 98 99 problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache, 100 authctxt->krb5_user); 101 if (problem) 102 goto out; 103 104 restore_uid(); 105 106 problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user, 107 ccache, password, 1, NULL); 108 109 temporarily_use_uid(authctxt->pw); 110 111 if (problem) 112 goto out; 113 114 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, 115 &authctxt->krb5_fwd_ccache); 116 if (problem) 117 goto out; 118 119 problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache, 120 authctxt->krb5_fwd_ccache); 121 krb5_cc_destroy(authctxt->krb5_ctx, ccache); 122 ccache = NULL; 123 if (problem) 124 goto out; 125 126 #else 127 problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds, 128 authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL); 129 if (problem) 130 goto out; 131 132 problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL, 133 KRB5_NT_SRV_HST, &server); 134 if (problem) 135 goto out; 136 137 restore_uid(); 138 problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server, 139 NULL, NULL, NULL); 140 krb5_free_principal(authctxt->krb5_ctx, server); 141 temporarily_use_uid(authctxt->pw); 142 if (problem) 143 goto out; 144 145 if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user, 146 authctxt->pw->pw_name)) { 147 problem = -1; 148 goto out; 149 } 150 151 problem = ssh_krb5_cc_gen(authctxt->krb5_ctx, &authctxt->krb5_fwd_ccache); 152 if (problem) 153 goto out; 154 155 problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, 156 authctxt->krb5_user); 157 if (problem) 158 goto out; 159 160 problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, 161 &creds); 162 if (problem) 163 goto out; 164 #endif 165 166 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); 167 168 len = strlen(authctxt->krb5_ticket_file) + 6; 169 authctxt->krb5_ccname = xmalloc(len); 170 snprintf(authctxt->krb5_ccname, len, "FILE:%s", 171 authctxt->krb5_ticket_file); 172 173 #ifdef USE_PAM 174 if (options.use_pam) 175 do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname); 176 #endif 177 178 out: 179 restore_uid(); 180 181 if (problem) { 182 if (ccache) 183 krb5_cc_destroy(authctxt->krb5_ctx, ccache); 184 185 if (authctxt->krb5_ctx != NULL && problem!=-1) 186 debug("Kerberos password authentication failed: %s", 187 krb5_get_err_text(authctxt->krb5_ctx, problem)); 188 else 189 debug("Kerberos password authentication failed: %d", 190 problem); 191 192 krb5_cleanup_proc(authctxt); 193 194 if (options.kerberos_or_local_passwd) 195 return (-1); 196 else 197 return (0); 198 } 199 return (authctxt->valid ? 1 : 0); 200 } 201 202 void 203 krb5_cleanup_proc(Authctxt *authctxt) 204 { 205 debug("krb5_cleanup_proc called"); 206 if (authctxt->krb5_fwd_ccache) { 207 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); 208 authctxt->krb5_fwd_ccache = NULL; 209 } 210 if (authctxt->krb5_user) { 211 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user); 212 authctxt->krb5_user = NULL; 213 } 214 if (authctxt->krb5_ctx) { 215 krb5_free_context(authctxt->krb5_ctx); 216 authctxt->krb5_ctx = NULL; 217 } 218 } 219 220 #ifndef HEIMDAL 221 krb5_error_code 222 ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) { 223 int tmpfd, ret; 224 char ccname[40]; 225 mode_t old_umask; 226 227 ret = snprintf(ccname, sizeof(ccname), 228 "FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid()); 229 if (ret < 0 || (size_t)ret >= sizeof(ccname)) 230 return ENOMEM; 231 232 old_umask = umask(0177); 233 tmpfd = mkstemp(ccname + strlen("FILE:")); 234 umask(old_umask); 235 if (tmpfd == -1) { 236 logit("mkstemp(): %.100s", strerror(errno)); 237 return errno; 238 } 239 240 if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) { 241 logit("fchmod(): %.100s", strerror(errno)); 242 close(tmpfd); 243 return errno; 244 } 245 close(tmpfd); 246 247 return (krb5_cc_resolve(ctx, ccname, ccache)); 248 } 249 #endif /* !HEIMDAL */ 250 #endif /* KRB5 */ 251