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/* $OpenBSD: auth-krb5.c,v 1.19 2006/08/03 03:34:41 deraadt Exp $ */
/*
* Kerberos v5 authentication and ticket-passing routines.
*
* $FreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp $
*/
/*
* Copyright (c) 2002 Daniel Kouril. 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"
#include <sys/types.h>
#include <pwd.h>
#include <stdarg.h>
#include "xmalloc.h"
#include "ssh.h"
#include "ssh1.h"
#include "packet.h"
#include "log.h"
#include "buffer.h"
#include "servconf.h"
#include "uidswap.h"
#include "key.h"
#include "hostfile.h"
#include "auth.h"
#ifdef KRB5
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <krb5.h>
extern ServerOptions options;
static int
krb5_init(void *context)
{
Authctxt *authctxt = (Authctxt *)context;
krb5_error_code problem;
if (authctxt->krb5_ctx == NULL) {
problem = krb5_init_context(&authctxt->krb5_ctx);
if (problem)
return (problem);
}
return (0);
}
int
auth_krb5_password(Authctxt *authctxt, const char *password)
{
#ifndef HEIMDAL
krb5_creds creds;
krb5_principal server;
#endif
krb5_error_code problem;
krb5_ccache ccache = NULL;
int len;
char *client, *platform_client;
/* get platform-specific kerberos client principal name (if it exists) */
platform_client = platform_krb5_get_principal_name(authctxt->pw->pw_name);
client = platform_client ? platform_client : authctxt->pw->pw_name;
temporarily_use_uid(authctxt->pw);
problem = krb5_init(authctxt);
if (problem)
goto out;
problem = krb5_parse_name(authctxt->krb5_ctx, client,
&authctxt->krb5_user);
if (problem)
goto out;
#ifdef HEIMDAL
problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache);
if (problem)
goto out;
problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
authctxt->krb5_user);
if (problem)
goto out;
restore_uid();
problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
ccache, password, 1, NULL);
temporarily_use_uid(authctxt->pw);
if (problem)
goto out;
problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops,
&authctxt->krb5_fwd_ccache);
if (problem)
goto out;
problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache,
authctxt->krb5_fwd_ccache);
krb5_cc_destroy(authctxt->krb5_ctx, ccache);
ccache = NULL;
if (problem)
goto out;
#else
problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds,
authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL);
if (problem)
goto out;
problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
KRB5_NT_SRV_HST, &server);
if (problem)
goto out;
restore_uid();
problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server,
NULL, NULL, NULL);
krb5_free_principal(authctxt->krb5_ctx, server);
temporarily_use_uid(authctxt->pw);
if (problem)
goto out;
if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user, client)) {
problem = -1;
goto out;
}
problem = ssh_krb5_cc_gen(authctxt->krb5_ctx, &authctxt->krb5_fwd_ccache);
if (problem)
goto out;
problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
authctxt->krb5_user);
if (problem)
goto out;
problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
&creds);
if (problem)
goto out;
#endif
authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
len = strlen(authctxt->krb5_ticket_file) + 6;
authctxt->krb5_ccname = xmalloc(len);
snprintf(authctxt->krb5_ccname, len, "FILE:%s",
authctxt->krb5_ticket_file);
#ifdef USE_PAM
if (options.use_pam)
do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname);
#endif
out:
restore_uid();
if (platform_client != NULL)
xfree(platform_client);
if (problem) {
if (ccache)
krb5_cc_destroy(authctxt->krb5_ctx, ccache);
if (authctxt->krb5_ctx != NULL && problem!=-1)
debug("Kerberos password authentication failed: %s",
krb5_get_err_text(authctxt->krb5_ctx, problem));
else
debug("Kerberos password authentication failed: %d",
problem);
krb5_cleanup_proc(authctxt);
if (options.kerberos_or_local_passwd)
return (-1);
else
return (0);
}
return (authctxt->valid ? 1 : 0);
}
void
krb5_cleanup_proc(Authctxt *authctxt)
{
debug("krb5_cleanup_proc called");
if (authctxt->krb5_fwd_ccache) {
krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
authctxt->krb5_fwd_ccache = NULL;
}
if (authctxt->krb5_user) {
krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
authctxt->krb5_user = NULL;
}
if (authctxt->krb5_ctx) {
krb5_free_context(authctxt->krb5_ctx);
authctxt->krb5_ctx = NULL;
}
}
#ifndef HEIMDAL
krb5_error_code
ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) {
int tmpfd, ret;
char ccname[40];
mode_t old_umask;
ret = snprintf(ccname, sizeof(ccname),
"FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid());
if (ret < 0 || (size_t)ret >= sizeof(ccname))
return ENOMEM;
old_umask = umask(0177);
tmpfd = mkstemp(ccname + strlen("FILE:"));
umask(old_umask);
if (tmpfd == -1) {
logit("mkstemp(): %.100s", strerror(errno));
return errno;
}
if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) {
logit("fchmod(): %.100s", strerror(errno));
close(tmpfd);
return errno;
}
close(tmpfd);
return (krb5_cc_resolve(ctx, ccname, ccache));
}
#endif /* !HEIMDAL */
#endif /* KRB5 */
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