gss-serv-krb5.c revision 1.5.18.1
1 /* $NetBSD: gss-serv-krb5.c,v 1.5.18.1 2017/08/15 04:40:16 snj Exp $ */ 2 /* $OpenBSD: gss-serv-krb5.c,v 1.8 2013/07/20 01:55:13 djm Exp $ */ 3 4 /* 5 * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include "includes.h" 29 __RCSID("$NetBSD: gss-serv-krb5.c,v 1.5.18.1 2017/08/15 04:40:16 snj Exp $"); 30 #ifdef GSSAPI 31 #ifdef KRB5 32 33 #include <sys/types.h> 34 35 #include <stdarg.h> 36 #include <string.h> 37 38 #include "xmalloc.h" 39 #include "key.h" 40 #include "hostfile.h" 41 #include "auth.h" 42 #include "log.h" 43 44 #include "buffer.h" 45 #include "misc.h" 46 #include "servconf.h" 47 #include "ssh-gss.h" 48 49 extern ServerOptions options; 50 51 #include <krb5.h> 52 #include <gssapi/gssapi_krb5.h> 53 54 static krb5_context krb_context = NULL; 55 56 /* Initialise the krb5 library, for the stuff that GSSAPI won't do */ 57 58 static int 59 ssh_gssapi_krb5_init(void) 60 { 61 krb5_error_code problem; 62 63 if (krb_context != NULL) 64 return 1; 65 66 problem = krb5_init_context(&krb_context); 67 if (problem) { 68 logit("Cannot initialize krb5 context"); 69 return 0; 70 } 71 #ifdef isneeded 72 krb5_init_ets(krb_context); 73 #endif 74 75 return 1; 76 } 77 78 /* Check if this user is OK to login. This only works with krb5 - other 79 * GSSAPI mechanisms will need their own. 80 * Returns true if the user is OK to log in, otherwise returns 0 81 */ 82 83 static int 84 ssh_gssapi_krb5_userok(ssh_gssapi_client *client, char *name) 85 { 86 krb5_principal princ; 87 int retval; 88 const char *errmsg; 89 90 if (ssh_gssapi_krb5_init() == 0) 91 return 0; 92 93 if ((retval = krb5_parse_name(krb_context, client->exportedname.value, 94 &princ))) { 95 errmsg = krb5_get_error_message(krb_context, retval); 96 logit("krb5_parse_name(): %.100s", errmsg); 97 krb5_free_error_message(krb_context, errmsg); 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 size_t len; 123 const char *errmsg; 124 125 if (client->creds == NULL) { 126 debug("No credentials stored"); 127 return; 128 } 129 130 if (ssh_gssapi_krb5_init() == 0) 131 return; 132 133 if ((problem = krb5_cc_new_unique(krb_context, krb5_fcc_ops.prefix, 134 NULL, &ccache)) != 0) { 135 errmsg = krb5_get_error_message(krb_context, problem); 136 logit("krb5_cc_new_unique(): %.100s", errmsg); 137 krb5_free_error_message(krb_context, errmsg); 138 return; 139 } 140 141 if ((problem = krb5_parse_name(krb_context, 142 client->exportedname.value, &princ))) { 143 errmsg = krb5_get_error_message(krb_context, problem); 144 logit("krb5_parse_name(): %.100s", errmsg); 145 krb5_free_error_message(krb_context, errmsg); 146 krb5_cc_destroy(krb_context, ccache); 147 return; 148 } 149 150 if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) { 151 errmsg = krb5_get_error_message(krb_context, problem); 152 logit("krb5_cc_initialize(): %.100s", errmsg); 153 krb5_free_error_message(krb_context, errmsg); 154 krb5_free_principal(krb_context, princ); 155 krb5_cc_destroy(krb_context, ccache); 156 return; 157 } 158 159 krb5_free_principal(krb_context, princ); 160 161 if ((maj_status = gss_krb5_copy_ccache(&min_status, 162 client->creds, ccache))) { 163 logit("gss_krb5_copy_ccache() failed"); 164 krb5_cc_destroy(krb_context, ccache); 165 return; 166 } 167 168 client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache)); 169 client->store.envvar = __UNCONST("KRB5CCNAME"); 170 len = strlen(client->store.filename) + 6; 171 client->store.envval = xmalloc(len); 172 snprintf(client->store.envval, len, "FILE:%s", client->store.filename); 173 174 #ifdef USE_PAM 175 if (options.use_pam) 176 do_pam_putenv(client->store.envvar, client->store.envval); 177 #endif 178 179 krb5_cc_close(krb_context, ccache); 180 181 return; 182 } 183 184 ssh_gssapi_mech gssapi_kerberos_mech = { 185 "toWM5Slw5Ew8Mqkay+al2g==", 186 "Kerberos", 187 {9, __UNCONST("\x2A\x86\x48\x86\xF7\x12\x01\x02\x02")}, 188 NULL, 189 &ssh_gssapi_krb5_userok, 190 NULL, 191 &ssh_gssapi_krb5_storecreds 192 }; 193 194 #endif /* KRB5 */ 195 196 #endif /* GSSAPI */ 197
Indexes created Thu Aug 06 00:25:04 UTC 2026