1 /* $OpenBSD: gss-serv-krb5.c,v 1.5 2006/03/25 22:22:43 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 #include <krb5.h> 40 41 static krb5_context krb_context = NULL; 42 43 /* Initialise the krb5 library, for the stuff that GSSAPI won't do */ 44 45 static int 46 ssh_gssapi_krb5_init(void) 47 { 48 krb5_error_code problem; 49 50 if (krb_context != NULL) 51 return 1; 52 53 problem = krb5_init_context(&krb_context); 54 if (problem) { 55 logit("Cannot initialize krb5 context"); 56 return 0; 57 } 58 krb5_init_ets(krb_context); 59 60 return 1; 61 } 62 63 /* Check if this user is OK to login. This only works with krb5 - other 64 * GSSAPI mechanisms will need their own. 65 * Returns true if the user is OK to log in, otherwise returns 0 66 */ 67 68 static int 69 ssh_gssapi_krb5_userok(ssh_gssapi_client *client, char *name) 70 { 71 krb5_principal princ; 72 int retval; 73 74 if (ssh_gssapi_krb5_init() == 0) 75 return 0; 76 77 if ((retval = krb5_parse_name(krb_context, client->exportedname.value, 78 &princ))) { 79 logit("krb5_parse_name(): %.100s", 80 krb5_get_err_text(krb_context, retval)); 81 return 0; 82 } 83 if (krb5_kuserok(krb_context, princ, name)) { 84 retval = 1; 85 logit("Authorized to %s, krb5 principal %s (krb5_kuserok)", 86 name, (char *)client->displayname.value); 87 } else 88 retval = 0; 89 90 krb5_free_principal(krb_context, princ); 91 return retval; 92 } 93 94 95 /* This writes out any forwarded credentials from the structure populated 96 * during userauth. Called after we have setuid to the user */ 97 98 static void 99 ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client) 100 { 101 krb5_ccache ccache; 102 krb5_error_code problem; 103 krb5_principal princ; 104 OM_uint32 maj_status, min_status; 105 106 if (client->creds == NULL) { 107 debug("No credentials stored"); 108 return; 109 } 110 111 if (ssh_gssapi_krb5_init() == 0) 112 return; 113 114 if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) { 115 logit("krb5_cc_gen_new(): %.100s", 116 krb5_get_err_text(krb_context, problem)); 117 return; 118 } 119 120 if ((problem = krb5_parse_name(krb_context, 121 client->exportedname.value, &princ))) { 122 logit("krb5_parse_name(): %.100s", 123 krb5_get_err_text(krb_context, problem)); 124 krb5_cc_destroy(krb_context, ccache); 125 return; 126 } 127 128 if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) { 129 logit("krb5_cc_initialize(): %.100s", 130 krb5_get_err_text(krb_context, problem)); 131 krb5_free_principal(krb_context, princ); 132 krb5_cc_destroy(krb_context, ccache); 133 return; 134 } 135 136 krb5_free_principal(krb_context, princ); 137 138 if ((maj_status = gss_krb5_copy_ccache(&min_status, 139 client->creds, ccache))) { 140 logit("gss_krb5_copy_ccache() failed"); 141 krb5_cc_destroy(krb_context, ccache); 142 return; 143 } 144 145 client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache)); 146 client->store.envvar = "KRB5CCNAME"; 147 client->store.envval = xstrdup(client->store.filename); 148 149 krb5_cc_close(krb_context, ccache); 150 151 return; 152 } 153 154 ssh_gssapi_mech gssapi_kerberos_mech = { 155 "toWM5Slw5Ew8Mqkay+al2g==", 156 "Kerberos", 157 {9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"}, 158 NULL, 159 &ssh_gssapi_krb5_userok, 160 NULL, 161 &ssh_gssapi_krb5_storecreds 162 }; 163 164 #endif /* KRB5 */ 165 166 #endif /* GSSAPI */ 167