1 /* $OpenBSD: gss-serv-krb5.c,v 1.3 2004/07/21 10:36:23 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 "auth.h" 33 #include "xmalloc.h" 34 #include "log.h" 35 #include "servconf.h" 36 37 #include "ssh-gss.h" 38 39 extern ServerOptions options; 40 41 #ifdef HEIMDAL 42 # include <krb5.h> 43 #else 44 # ifdef HAVE_GSSAPI_KRB5 45 # include <gssapi_krb5.h> 46 # elif HAVE_GSSAPI_GSSAPI_KRB5 47 # include <gssapi/gssapi_krb5.h> 48 # endif 49 #endif 50 51 static krb5_context krb_context = NULL; 52 53 /* Initialise the krb5 library, for the stuff that GSSAPI won't do */ 54 55 static int 56 ssh_gssapi_krb5_init(void) 57 { 58 krb5_error_code problem; 59 60 if (krb_context != NULL) 61 return 1; 62 63 problem = krb5_init_context(&krb_context); 64 if (problem) { 65 logit("Cannot initialize krb5 context"); 66 return 0; 67 } 68 69 return 1; 70 } 71 72 /* Check if this user is OK to login. This only works with krb5 - other 73 * GSSAPI mechanisms will need their own. 74 * Returns true if the user is OK to log in, otherwise returns 0 75 */ 76 77 static int 78 ssh_gssapi_krb5_userok(ssh_gssapi_client *client, char *name) 79 { 80 krb5_principal princ; 81 int retval; 82 83 if (ssh_gssapi_krb5_init() == 0) 84 return 0; 85 86 if ((retval = krb5_parse_name(krb_context, client->exportedname.value, 87 &princ))) { 88 logit("krb5_parse_name(): %.100s", 89 krb5_get_err_text(krb_context, retval)); 90 return 0; 91 } 92 if (krb5_kuserok(krb_context, princ, name)) { 93 retval = 1; 94 logit("Authorized to %s, krb5 principal %s (krb5_kuserok)", 95 name, (char *)client->displayname.value); 96 } else 97 retval = 0; 98 99 krb5_free_principal(krb_context, princ); 100 return retval; 101 } 102 103 104 /* This writes out any forwarded credentials from the structure populated 105 * during userauth. Called after we have setuid to the user */ 106 107 static void 108 ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client) 109 { 110 krb5_ccache ccache; 111 krb5_error_code problem; 112 krb5_principal princ; 113 OM_uint32 maj_status, min_status; 114 int len; 115 116 if (client->creds == NULL) { 117 debug("No credentials stored"); 118 return; 119 } 120 121 if (ssh_gssapi_krb5_init() == 0) 122 return; 123 124 #ifdef HEIMDAL 125 if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) { 126 logit("krb5_cc_gen_new(): %.100s", 127 krb5_get_err_text(krb_context, problem)); 128 return; 129 } 130 #else 131 if ((problem = ssh_krb5_cc_gen(krb_context, &ccache))) { 132 logit("ssh_krb5_cc_gen(): %.100s", 133 krb5_get_err_text(krb_context, problem)); 134 return; 135 } 136 #endif /* #ifdef HEIMDAL */ 137 138 if ((problem = krb5_parse_name(krb_context, 139 client->exportedname.value, &princ))) { 140 logit("krb5_parse_name(): %.100s", 141 krb5_get_err_text(krb_context, problem)); 142 krb5_cc_destroy(krb_context, ccache); 143 return; 144 } 145 146 if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) { 147 logit("krb5_cc_initialize(): %.100s", 148 krb5_get_err_text(krb_context, problem)); 149 krb5_free_principal(krb_context, princ); 150 krb5_cc_destroy(krb_context, ccache); 151 return; 152 } 153 154 krb5_free_principal(krb_context, princ); 155 156 if ((maj_status = gss_krb5_copy_ccache(&min_status, 157 client->creds, ccache))) { 158 logit("gss_krb5_copy_ccache() failed"); 159 krb5_cc_destroy(krb_context, ccache); 160 return; 161 } 162 163 client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache)); 164 client->store.envvar = "KRB5CCNAME"; 165 len = strlen(client->store.filename) + 6; 166 client->store.envval = xmalloc(len); 167 snprintf(client->store.envval, len, "FILE:%s", client->store.filename); 168 169 #ifdef USE_PAM 170 if (options.use_pam) 171 do_pam_putenv(client->store.envvar, client->store.envval); 172 #endif 173 174 krb5_cc_close(krb_context, ccache); 175 176 return; 177 } 178 179 ssh_gssapi_mech gssapi_kerberos_mech = { 180 "toWM5Slw5Ew8Mqkay+al2g==", 181 "Kerberos", 182 {9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"}, 183 NULL, 184 &ssh_gssapi_krb5_userok, 185 NULL, 186 &ssh_gssapi_krb5_storecreds 187 }; 188 189 #endif /* KRB5 */ 190 191 #endif /* GSSAPI */ 192