1 /* $OpenBSD: gss-serv-krb5.c,v 1.8 2013/07/20 01:55:13 djm Exp $ */ 2 3 /* 4 * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include "includes.h" 28 29 #ifdef GSSAPI 30 #ifdef KRB5 31 32 #include <sys/types.h> 33 34 #include <stdarg.h> 35 #include <string.h> 36 37 #include "xmalloc.h" 38 #include "key.h" 39 #include "hostfile.h" 40 #include "auth.h" 41 #include "log.h" 42 #include "misc.h" 43 #include "servconf.h" 44 45 #include "buffer.h" 46 #include "ssh-gss.h" 47 48 extern ServerOptions options; 49 50 #ifdef HEIMDAL 51 # include <krb5.h> 52 #endif 53 #ifdef HAVE_GSSAPI_KRB5_H 54 # include <gssapi_krb5.h> 55 #elif HAVE_GSSAPI_GSSAPI_KRB5_H 56 # include <gssapi/gssapi_krb5.h> 57 #endif 58 59 static krb5_context krb_context = NULL; 60 61 /* Initialise the krb5 library, for the stuff that GSSAPI won't do */ 62 63 static int 64 ssh_gssapi_krb5_init(void) 65 { 66 krb5_error_code problem; 67 68 if (krb_context != NULL) 69 return 1; 70 71 problem = krb5_init_context(&krb_context); 72 if (problem) { 73 logit("Cannot initialize krb5 context"); 74 return 0; 75 } 76 77 return 1; 78 } 79 80 /* Check if this user is OK to login. This only works with krb5 - other 81 * GSSAPI mechanisms will need their own. 82 * Returns true if the user is OK to log in, otherwise returns 0 83 */ 84 85 static int 86 ssh_gssapi_krb5_userok(ssh_gssapi_client *client, char *name) 87 { 88 krb5_principal princ; 89 int retval; 90 const char *errmsg; 91 92 if (ssh_gssapi_krb5_init() == 0) 93 return 0; 94 95 if ((retval = krb5_parse_name(krb_context, client->exportedname.value, 96 &princ))) { 97 errmsg = krb5_get_error_message(krb_context, retval); 98 logit("krb5_parse_name(): %.100s", errmsg); 99 krb5_free_error_message(krb_context, errmsg); 100 return 0; 101 } 102 if (krb5_kuserok(krb_context, princ, name)) { 103 retval = 1; 104 logit("Authorized to %s, krb5 principal %s (krb5_kuserok)", 105 name, (char *)client->displayname.value); 106 } else 107 retval = 0; 108 109 krb5_free_principal(krb_context, princ); 110 return retval; 111 } 112 113 114 /* This writes out any forwarded credentials from the structure populated 115 * during userauth. Called after we have setuid to the user */ 116 117 static void 118 ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client) 119 { 120 krb5_ccache ccache; 121 krb5_error_code problem; 122 krb5_principal princ; 123 OM_uint32 maj_status, min_status; 124 int len; 125 const char *errmsg; 126 127 if (client->creds == NULL) { 128 debug("No credentials stored"); 129 return; 130 } 131 132 if (ssh_gssapi_krb5_init() == 0) 133 return; 134 135 #ifdef HEIMDAL 136 # ifdef HAVE_KRB5_CC_NEW_UNIQUE 137 if ((problem = krb5_cc_new_unique(krb_context, krb5_fcc_ops.prefix, 138 NULL, &ccache)) != 0) { 139 errmsg = krb5_get_error_message(krb_context, problem); 140 logit("krb5_cc_new_unique(): %.100s", errmsg); 141 # else 142 if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) { 143 logit("krb5_cc_gen_new(): %.100s", 144 krb5_get_err_text(krb_context, problem)); 145 # endif 146 krb5_free_error_message(krb_context, errmsg); 147 return; 148 } 149 #else 150 if ((problem = ssh_krb5_cc_gen(krb_context, &ccache))) { 151 errmsg = krb5_get_error_message(krb_context, problem); 152 logit("ssh_krb5_cc_gen(): %.100s", errmsg); 153 krb5_free_error_message(krb_context, errmsg); 154 return; 155 } 156 #endif /* #ifdef HEIMDAL */ 157 158 if ((problem = krb5_parse_name(krb_context, 159 client->exportedname.value, &princ))) { 160 errmsg = krb5_get_error_message(krb_context, problem); 161 logit("krb5_parse_name(): %.100s", errmsg); 162 krb5_free_error_message(krb_context, errmsg); 163 return; 164 } 165 166 if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) { 167 errmsg = krb5_get_error_message(krb_context, problem); 168 logit("krb5_cc_initialize(): %.100s", errmsg); 169 krb5_free_error_message(krb_context, errmsg); 170 krb5_free_principal(krb_context, princ); 171 krb5_cc_destroy(krb_context, ccache); 172 return; 173 } 174 175 krb5_free_principal(krb_context, princ); 176 177 if ((maj_status = gss_krb5_copy_ccache(&min_status, 178 client->creds, ccache))) { 179 logit("gss_krb5_copy_ccache() failed"); 180 krb5_cc_destroy(krb_context, ccache); 181 return; 182 } 183 184 client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache)); 185 client->store.envvar = "KRB5CCNAME"; 186 len = strlen(client->store.filename) + 6; 187 client->store.envval = xmalloc(len); 188 snprintf(client->store.envval, len, "FILE:%s", client->store.filename); 189 190 #ifdef USE_PAM 191 if (options.use_pam) 192 do_pam_putenv(client->store.envvar, client->store.envval); 193 #endif 194 195 krb5_cc_close(krb_context, ccache); 196 197 return; 198 } 199 200 ssh_gssapi_mech gssapi_kerberos_mech = { 201 "toWM5Slw5Ew8Mqkay+al2g==", 202 "Kerberos", 203 {9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"}, 204 NULL, 205 &ssh_gssapi_krb5_userok, 206 NULL, 207 &ssh_gssapi_krb5_storecreds 208 }; 209 210 #endif /* KRB5 */ 211 212 #endif /* GSSAPI */ 213
