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 #ifdef GSSAPI 28 #ifdef KRB5 29 30 #include <sys/types.h> 31 32 #include "xmalloc.h" 33 #include "key.h" 34 #include "hostfile.h" 35 #include "auth.h" 36 #include "log.h" 37 38 #include "buffer.h" 39 #include "ssh-gss.h" 40 41 #include <krb5.h> 42 43 static krb5_context krb_context = NULL; 44 45 /* Initialise the krb5 library, for the stuff that GSSAPI won't do */ 46 47 static int 48 ssh_gssapi_krb5_init(void) 49 { 50 krb5_error_code problem; 51 52 if (krb_context != NULL) 53 return 1; 54 55 problem = krb5_init_context(&krb_context); 56 if (problem) { 57 logit("Cannot initialize krb5 context"); 58 return 0; 59 } 60 krb5_init_ets(krb_context); 61 62 return 1; 63 } 64 65 /* Check if this user is OK to login. This only works with krb5 - other 66 * GSSAPI mechanisms will need their own. 67 * Returns true if the user is OK to log in, otherwise returns 0 68 */ 69 70 static int 71 ssh_gssapi_krb5_userok(ssh_gssapi_client *client, char *name) 72 { 73 krb5_principal princ; 74 int retval; 75 76 if (ssh_gssapi_krb5_init() == 0) 77 return 0; 78 79 if ((retval = krb5_parse_name(krb_context, client->exportedname.value, 80 &princ))) { 81 logit("krb5_parse_name(): %.100s", 82 krb5_get_err_text(krb_context, retval)); 83 return 0; 84 } 85 if (krb5_kuserok(krb_context, princ, name)) { 86 retval = 1; 87 logit("Authorized to %s, krb5 principal %s (krb5_kuserok)", 88 name, (char *)client->displayname.value); 89 } else 90 retval = 0; 91 92 krb5_free_principal(krb_context, princ); 93 return retval; 94 } 95 96 97 /* This writes out any forwarded credentials from the structure populated 98 * during userauth. Called after we have setuid to the user */ 99 100 static void 101 ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client) 102 { 103 krb5_ccache ccache; 104 krb5_error_code problem; 105 krb5_principal princ; 106 OM_uint32 maj_status, min_status; 107 108 if (client->creds == NULL) { 109 debug("No credentials stored"); 110 return; 111 } 112 113 if (ssh_gssapi_krb5_init() == 0) 114 return; 115 116 if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) { 117 logit("krb5_cc_gen_new(): %.100s", 118 krb5_get_err_text(krb_context, problem)); 119 return; 120 } 121 122 if ((problem = krb5_parse_name(krb_context, 123 client->exportedname.value, &princ))) { 124 logit("krb5_parse_name(): %.100s", 125 krb5_get_err_text(krb_context, problem)); 126 krb5_cc_destroy(krb_context, ccache); 127 return; 128 } 129 130 if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) { 131 logit("krb5_cc_initialize(): %.100s", 132 krb5_get_err_text(krb_context, problem)); 133 krb5_free_principal(krb_context, princ); 134 krb5_cc_destroy(krb_context, ccache); 135 return; 136 } 137 138 krb5_free_principal(krb_context, princ); 139 140 if ((maj_status = gss_krb5_copy_ccache(&min_status, 141 client->creds, ccache))) { 142 logit("gss_krb5_copy_ccache() failed"); 143 krb5_cc_destroy(krb_context, ccache); 144 return; 145 } 146 147 client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache)); 148 client->store.envvar = "KRB5CCNAME"; 149 client->store.envval = xstrdup(client->store.filename); 150 151 krb5_cc_close(krb_context, ccache); 152 153 return; 154 } 155 156 ssh_gssapi_mech gssapi_kerberos_mech = { 157 "toWM5Slw5Ew8Mqkay+al2g==", 158 "Kerberos", 159 {9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"}, 160 NULL, 161 &ssh_gssapi_krb5_userok, 162 NULL, 163 &ssh_gssapi_krb5_storecreds 164 }; 165 166 #endif /* KRB5 */ 167 168 #endif /* GSSAPI */ 169