1132451Sroberto/* $NetBSD: gss-serv-krb5.c,v 1.12 2019/01/27 02:08:33 pgoyette Exp $ */ 2132451Sroberto/* $OpenBSD: gss-serv-krb5.c,v 1.9 2018/07/09 21:37:55 markus Exp $ */ 3132451Sroberto 4132451Sroberto/* 5132451Sroberto * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved. 6132451Sroberto * 7132451Sroberto * Redistribution and use in source and binary forms, with or without 8132451Sroberto * modification, are permitted provided that the following conditions 9132451Sroberto * are met: 10132451Sroberto * 1. Redistributions of source code must retain the above copyright 11132451Sroberto * notice, this list of conditions and the following disclaimer. 12132451Sroberto * 2. Redistributions in binary form must reproduce the above copyright 13132451Sroberto * notice, this list of conditions and the following disclaimer in the 14132451Sroberto * documentation and/or other materials provided with the distribution. 15132451Sroberto * 16132451Sroberto * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR 17132451Sroberto * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18132451Sroberto * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19132451Sroberto * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20132451Sroberto * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21132451Sroberto * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22132451Sroberto * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23132451Sroberto * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24132451Sroberto * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25132451Sroberto * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26132451Sroberto */ 27132451Sroberto 28132451Sroberto#include "includes.h" 29132451Sroberto__RCSID("$NetBSD: gss-serv-krb5.c,v 1.12 2019/01/27 02:08:33 pgoyette Exp $"); 30132451Sroberto#ifdef GSSAPI 31132451Sroberto#ifdef KRB5 32 33#include <sys/types.h> 34 35#include <stdarg.h> 36#include <string.h> 37 38#include "xmalloc.h" 39#include "sshkey.h" 40#include "hostfile.h" 41#include "auth.h" 42#include "log.h" 43#include "misc.h" 44#include "servconf.h" 45 46#include "ssh-gss.h" 47 48extern ServerOptions options; 49 50#include <krb5.h> 51#include <gssapi/gssapi_krb5.h> 52 53static krb5_context krb_context = NULL; 54 55/* Initialise the krb5 library, for the stuff that GSSAPI won't do */ 56 57static int 58ssh_gssapi_krb5_init(void) 59{ 60 krb5_error_code problem; 61 62 if (krb_context != NULL) 63 return 1; 64 65 problem = krb5_init_context(&krb_context); 66 if (problem) { 67 logit("Cannot initialize krb5 context"); 68 return 0; 69 } 70#ifdef isneeded 71 krb5_init_ets(krb_context); 72#endif 73 74 return 1; 75} 76 77/* Check if this user is OK to login. This only works with krb5 - other 78 * GSSAPI mechanisms will need their own. 79 * Returns true if the user is OK to log in, otherwise returns 0 80 */ 81 82static int 83ssh_gssapi_krb5_userok(ssh_gssapi_client *client, char *name) 84{ 85 krb5_principal princ; 86 int retval; 87 const char *errmsg; 88 89 if (ssh_gssapi_krb5_init() == 0) 90 return 0; 91 92 if ((retval = krb5_parse_name(krb_context, client->exportedname.value, 93 &princ))) { 94 errmsg = krb5_get_error_message(krb_context, retval); 95 logit("krb5_parse_name(): %.100s", errmsg); 96 krb5_free_error_message(krb_context, errmsg); 97 return 0; 98 } 99 if (krb5_kuserok(krb_context, princ, name)) { 100 retval = 1; 101 logit("Authorized to %s, krb5 principal %s (krb5_kuserok)", 102 name, (char *)client->displayname.value); 103 } else 104 retval = 0; 105 106 krb5_free_principal(krb_context, princ); 107 return retval; 108} 109 110 111/* This writes out any forwarded credentials from the structure populated 112 * during userauth. Called after we have setuid to the user */ 113 114static void 115ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client) 116{ 117 krb5_ccache ccache; 118 krb5_error_code problem; 119 krb5_principal princ; 120 OM_uint32 maj_status, min_status; 121 size_t len; 122 const char *errmsg; 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 if ((problem = krb5_cc_new_unique(krb_context, krb5_fcc_ops.prefix, 133 NULL, &ccache)) != 0) { 134 errmsg = krb5_get_error_message(krb_context, problem); 135 logit("krb5_cc_new_unique(): %.100s", errmsg); 136 krb5_free_error_message(krb_context, errmsg); 137 return; 138 } 139 140 if ((problem = krb5_parse_name(krb_context, 141 client->exportedname.value, &princ))) { 142 errmsg = krb5_get_error_message(krb_context, problem); 143 logit("krb5_parse_name(): %.100s", errmsg); 144 krb5_free_error_message(krb_context, errmsg); 145 krb5_cc_destroy(krb_context, ccache); 146 return; 147 } 148 149 if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) { 150 errmsg = krb5_get_error_message(krb_context, problem); 151 logit("krb5_cc_initialize(): %.100s", errmsg); 152 krb5_free_error_message(krb_context, errmsg); 153 krb5_free_principal(krb_context, princ); 154 krb5_cc_destroy(krb_context, ccache); 155 return; 156 } 157 158 krb5_free_principal(krb_context, princ); 159 160 if ((maj_status = gss_krb5_copy_ccache(&min_status, 161 client->creds, ccache))) { 162 logit("gss_krb5_copy_ccache() failed"); 163 krb5_cc_destroy(krb_context, ccache); 164 return; 165 } 166 167 client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache)); 168 client->store.envvar = __UNCONST("KRB5CCNAME"); 169 len = strlen(client->store.filename) + 6; 170 client->store.envval = xmalloc(len); 171 snprintf(client->store.envval, len, "FILE:%s", client->store.filename); 172 173#ifdef USE_PAM 174 if (options.use_pam) 175 do_pam_putenv(client->store.envvar, client->store.envval); 176#endif 177 178 krb5_cc_close(krb_context, ccache); 179 180 return; 181} 182 183ssh_gssapi_mech gssapi_kerberos_mech = { 184 "toWM5Slw5Ew8Mqkay+al2g==", 185 "Kerberos", 186 {9, __UNCONST("\x2A\x86\x48\x86\xF7\x12\x01\x02\x02")}, 187 NULL, 188 &ssh_gssapi_krb5_userok, 189 NULL, 190 &ssh_gssapi_krb5_storecreds 191}; 192 193#endif /* KRB5 */ 194 195#endif /* GSSAPI */ 196