1 /* 2 * Kerberos v5 authentication and ticket-passing routines. 3 * 4 * $xFreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp$ 5 */ 6 /* 7 * Copyright (c) 2002 Daniel Kouril. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30 #include "includes.h" 31 RCSID("$OpenBSD: auth-krb5.c,v 1.16 2005/11/21 09:42:10 dtucker Exp $"); 32 RCSID("$FreeBSD$"); 33 34 #include "ssh.h" 35 #include "ssh1.h" 36 #include "packet.h" 37 #include "xmalloc.h" 38 #include "log.h" 39 #include "servconf.h" 40 #include "uidswap.h" 41 #include "auth.h" 42 43 #ifdef KRB5 44 #include <krb5.h> 45 46 extern ServerOptions options; 47 48 static int 49 krb5_init(void *context) 50 { 51 Authctxt *authctxt = (Authctxt *)context; 52 krb5_error_code problem; 53 54 if (authctxt->krb5_ctx == NULL) { 55 problem = krb5_init_context(&authctxt->krb5_ctx); 56 if (problem) 57 return (problem); 58 } 59 return (0); 60 } 61 62 int 63 auth_krb5_password(Authctxt *authctxt, const char *password) 64 { 65 #ifndef HEIMDAL 66 krb5_creds creds; 67 krb5_principal server; 68 #endif 69 krb5_error_code problem; 70 krb5_ccache ccache = NULL; 71 int len; 72 73 temporarily_use_uid(authctxt->pw); 74 75 problem = krb5_init(authctxt); 76 if (problem) 77 goto out; 78 79 problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name, 80 &authctxt->krb5_user); 81 if (problem) 82 goto out; 83 84 #ifdef HEIMDAL 85 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache); 86 if (problem) 87 goto out; 88 89 problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache, 90 authctxt->krb5_user); 91 if (problem) 92 goto out; 93 94 restore_uid(); 95 96 problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user, 97 ccache, password, 1, NULL); 98 99 temporarily_use_uid(authctxt->pw); 100 101 if (problem) 102 goto out; 103 104 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, 105 &authctxt->krb5_fwd_ccache); 106 if (problem) 107 goto out; 108 109 problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache, 110 authctxt->krb5_fwd_ccache); 111 krb5_cc_destroy(authctxt->krb5_ctx, ccache); 112 ccache = NULL; 113 if (problem) 114 goto out; 115 116 #else 117 problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds, 118 authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL); 119 if (problem) 120 goto out; 121 122 problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL, 123 KRB5_NT_SRV_HST, &server); 124 if (problem) 125 goto out; 126 127 restore_uid(); 128 problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server, 129 NULL, NULL, NULL); 130 krb5_free_principal(authctxt->krb5_ctx, server); 131 temporarily_use_uid(authctxt->pw); 132 if (problem) 133 goto out; 134 135 if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user, 136 authctxt->pw->pw_name)) { 137 problem = -1; 138 goto out; 139 } 140 141 problem = ssh_krb5_cc_gen(authctxt->krb5_ctx, &authctxt->krb5_fwd_ccache); 142 if (problem) 143 goto out; 144 145 problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, 146 authctxt->krb5_user); 147 if (problem) 148 goto out; 149 150 problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, 151 &creds); 152 if (problem) 153 goto out; 154 #endif 155 156 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); 157 158 len = strlen(authctxt->krb5_ticket_file) + 6; 159 authctxt->krb5_ccname = xmalloc(len); 160 snprintf(authctxt->krb5_ccname, len, "FILE:%s", 161 authctxt->krb5_ticket_file); 162 163 #ifdef USE_PAM 164 if (options.use_pam) 165 do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname); 166 #endif 167 168 out: 169 restore_uid(); 170 171 if (problem) { 172 if (ccache) 173 krb5_cc_destroy(authctxt->krb5_ctx, ccache); 174 175 if (authctxt->krb5_ctx != NULL && problem!=-1) 176 debug("Kerberos password authentication failed: %s", 177 krb5_get_err_text(authctxt->krb5_ctx, problem)); 178 else 179 debug("Kerberos password authentication failed: %d", 180 problem); 181 182 krb5_cleanup_proc(authctxt); 183 184 if (options.kerberos_or_local_passwd) 185 return (-1); 186 else 187 return (0); 188 } 189 return (authctxt->valid ? 1 : 0); 190 } 191 192 void 193 krb5_cleanup_proc(Authctxt *authctxt) 194 { 195 debug("krb5_cleanup_proc called"); 196 if (authctxt->krb5_fwd_ccache) { 197 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); 198 authctxt->krb5_fwd_ccache = NULL; 199 } 200 if (authctxt->krb5_user) { 201 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user); 202 authctxt->krb5_user = NULL; 203 } 204 if (authctxt->krb5_ctx) { 205 krb5_free_context(authctxt->krb5_ctx); 206 authctxt->krb5_ctx = NULL; 207 } 208 } 209 210 #ifndef HEIMDAL 211 krb5_error_code 212 ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) { 213 int tmpfd, ret; 214 char ccname[40]; 215 mode_t old_umask; 216 217 ret = snprintf(ccname, sizeof(ccname), 218 "FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid()); 219 if (ret < 0 || (size_t)ret >= sizeof(ccname)) 220 return ENOMEM; 221 222 old_umask = umask(0177); 223 tmpfd = mkstemp(ccname + strlen("FILE:")); 224 umask(old_umask); 225 if (tmpfd == -1) { 226 logit("mkstemp(): %.100s", strerror(errno)); 227 return errno; 228 } 229 230 if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) { 231 logit("fchmod(): %.100s", strerror(errno)); 232 close(tmpfd); 233 return errno; 234 } 235 close(tmpfd); 236 237 return (krb5_cc_resolve(ctx, ccname, ccache)); 238 } 239 #endif /* !HEIMDAL */ 240 #endif /* KRB5 */ 241