1 /* $OpenBSD: gss-serv-krb5.c,v 1.7 2006/08/03 03:34:42 deraadt 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 "servconf.h" 43 44 #include "buffer.h" 45 #include "ssh-gss.h" 46 47 extern ServerOptions options; 48 49 #ifdef HEIMDAL 50 # include <krb5.h> 51 #else 52 # ifdef HAVE_GSSAPI_KRB5_H 53 # include <gssapi_krb5.h> 54 # elif HAVE_GSSAPI_GSSAPI_KRB5_H 55 # include <gssapi/gssapi_krb5.h> 56 # endif 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 91 if (ssh_gssapi_krb5_init() == 0) 92 return 0; 93 94 if ((retval = krb5_parse_name(krb_context, client->exportedname.value, 95 &princ))) { 96 logit("krb5_parse_name(): %.100s", 97 krb5_get_err_text(krb_context, retval)); 98 return 0; 99 } 100 if (krb5_kuserok(krb_context, princ, name)) { 101 retval = 1; 102 logit("Authorized to %s, krb5 principal %s (krb5_kuserok)", 103 name, (char *)client->displayname.value); 104 } else 105 retval = 0; 106 107 krb5_free_principal(krb_context, princ); 108 return retval; 109 } 110 111 112 /* This writes out any forwarded credentials from the structure populated 113 * during userauth. Called after we have setuid to the user */ 114 115 static void 116 ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client) 117 { 118 krb5_ccache ccache; 119 krb5_error_code problem; 120 krb5_principal princ; 121 OM_uint32 maj_status, min_status; 122 int len; 123 124 if (client->creds == NULL) { 125 debug("No credentials stored"); 126 return; 127 } 128 129 if (ssh_gssapi_krb5_init() == 0) 130 return; 131 132 #ifdef HEIMDAL 133 if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) { 134 logit("krb5_cc_gen_new(): %.100s", 135 krb5_get_err_text(krb_context, problem)); 136 return; 137 } 138 #else 139 if ((problem = ssh_krb5_cc_gen(krb_context, &ccache))) { 140 logit("ssh_krb5_cc_gen(): %.100s", 141 krb5_get_err_text(krb_context, problem)); 142 return; 143 } 144 #endif /* #ifdef HEIMDAL */ 145 146 if ((problem = krb5_parse_name(krb_context, 147 client->exportedname.value, &princ))) { 148 logit("krb5_parse_name(): %.100s", 149 krb5_get_err_text(krb_context, problem)); 150 krb5_cc_destroy(krb_context, ccache); 151 return; 152 } 153 154 if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) { 155 logit("krb5_cc_initialize(): %.100s", 156 krb5_get_err_text(krb_context, problem)); 157 krb5_free_principal(krb_context, princ); 158 krb5_cc_destroy(krb_context, ccache); 159 return; 160 } 161 162 krb5_free_principal(krb_context, princ); 163 164 if ((maj_status = gss_krb5_copy_ccache(&min_status, 165 client->creds, ccache))) { 166 logit("gss_krb5_copy_ccache() failed"); 167 krb5_cc_destroy(krb_context, ccache); 168 return; 169 } 170 171 client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache)); 172 client->store.envvar = "KRB5CCNAME"; 173 len = strlen(client->store.filename) + 6; 174 client->store.envval = xmalloc(len); 175 snprintf(client->store.envval, len, "FILE:%s", client->store.filename); 176 177 #ifdef USE_PAM 178 if (options.use_pam) 179 do_pam_putenv(client->store.envvar, client->store.envval); 180 #endif 181 182 krb5_cc_close(krb_context, ccache); 183 184 return; 185 } 186 187 ssh_gssapi_mech gssapi_kerberos_mech = { 188 "toWM5Slw5Ew8Mqkay+al2g==", 189 "Kerberos", 190 {9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"}, 191 NULL, 192 &ssh_gssapi_krb5_userok, 193 NULL, 194 &ssh_gssapi_krb5_storecreds 195 }; 196 197 #endif /* KRB5 */ 198 199 #endif /* GSSAPI */ 200