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/* $OpenBSD: gss-serv-krb5.c,v 1.9 2018/07/09 21:37:55 markus Exp $ */
/*
* Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
#ifdef GSSAPI
#ifdef KRB5
#include <sys/types.h>
#include <stdarg.h>
#include <string.h>
#include "xmalloc.h"
#include "sshkey.h"
#include "hostfile.h"
#include "auth.h"
#include "log.h"
#include "misc.h"
#include "servconf.h"
#include "ssh-gss.h"
extern ServerOptions options;
#ifdef HEIMDAL
# include <krb5.h>
#endif
#ifdef HAVE_GSSAPI_KRB5_H
# include <gssapi_krb5.h>
#elif HAVE_GSSAPI_GSSAPI_KRB5_H
# include <gssapi/gssapi_krb5.h>
#endif
static krb5_context krb_context = NULL;
/* Initialise the krb5 library, for the stuff that GSSAPI won't do */
static int
ssh_gssapi_krb5_init(void)
{
krb5_error_code problem;
if (krb_context != NULL)
return 1;
problem = krb5_init_context(&krb_context);
if (problem) {
logit("Cannot initialize krb5 context");
return 0;
}
return 1;
}
/* Check if this user is OK to login. This only works with krb5 - other
* GSSAPI mechanisms will need their own.
* Returns true if the user is OK to log in, otherwise returns 0
*/
static int
ssh_gssapi_krb5_userok(ssh_gssapi_client *client, char *name)
{
krb5_principal princ;
int retval;
const char *errmsg;
if (ssh_gssapi_krb5_init() == 0)
return 0;
if ((retval = krb5_parse_name(krb_context, client->exportedname.value,
&princ))) {
errmsg = krb5_get_error_message(krb_context, retval);
logit("krb5_parse_name(): %.100s", errmsg);
krb5_free_error_message(krb_context, errmsg);
return 0;
}
if (krb5_kuserok(krb_context, princ, name)) {
retval = 1;
logit("Authorized to %s, krb5 principal %s (krb5_kuserok)",
name, (char *)client->displayname.value);
} else
retval = 0;
krb5_free_principal(krb_context, princ);
return retval;
}
/* This writes out any forwarded credentials from the structure populated
* during userauth. Called after we have setuid to the user */
static void
ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
{
krb5_ccache ccache;
krb5_error_code problem;
krb5_principal princ;
OM_uint32 maj_status, min_status;
int len;
const char *errmsg;
if (client->creds == NULL) {
debug("No credentials stored");
return;
}
if (ssh_gssapi_krb5_init() == 0)
return;
#ifdef HEIMDAL
# ifdef HAVE_KRB5_CC_NEW_UNIQUE
if ((problem = krb5_cc_new_unique(krb_context, krb5_fcc_ops.prefix,
NULL, &ccache)) != 0) {
errmsg = krb5_get_error_message(krb_context, problem);
logit("krb5_cc_new_unique(): %.100s", errmsg);
# else
if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) {
logit("krb5_cc_gen_new(): %.100s",
krb5_get_err_text(krb_context, problem));
# endif
krb5_free_error_message(krb_context, errmsg);
return;
}
#else
if ((problem = ssh_krb5_cc_gen(krb_context, &ccache))) {
errmsg = krb5_get_error_message(krb_context, problem);
logit("ssh_krb5_cc_gen(): %.100s", errmsg);
krb5_free_error_message(krb_context, errmsg);
return;
}
#endif /* #ifdef HEIMDAL */
if ((problem = krb5_parse_name(krb_context,
client->exportedname.value, &princ))) {
errmsg = krb5_get_error_message(krb_context, problem);
logit("krb5_parse_name(): %.100s", errmsg);
krb5_free_error_message(krb_context, errmsg);
return;
}
if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) {
errmsg = krb5_get_error_message(krb_context, problem);
logit("krb5_cc_initialize(): %.100s", errmsg);
krb5_free_error_message(krb_context, errmsg);
krb5_free_principal(krb_context, princ);
krb5_cc_destroy(krb_context, ccache);
return;
}
krb5_free_principal(krb_context, princ);
if ((maj_status = gss_krb5_copy_ccache(&min_status,
client->creds, ccache))) {
logit("gss_krb5_copy_ccache() failed");
krb5_cc_destroy(krb_context, ccache);
return;
}
client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache));
client->store.envvar = "KRB5CCNAME";
len = strlen(client->store.filename) + 6;
client->store.envval = xmalloc(len);
snprintf(client->store.envval, len, "FILE:%s", client->store.filename);
#ifdef USE_PAM
if (options.use_pam)
do_pam_putenv(client->store.envvar, client->store.envval);
#endif
krb5_cc_close(krb_context, ccache);
return;
}
ssh_gssapi_mech gssapi_kerberos_mech = {
"toWM5Slw5Ew8Mqkay+al2g==",
"Kerberos",
{9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"},
NULL,
&ssh_gssapi_krb5_userok,
NULL,
&ssh_gssapi_krb5_storecreds
};
#endif /* KRB5 */
#endif /* GSSAPI */
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