407 lines
9.8 KiB
C
407 lines
9.8 KiB
C
/*
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* Kerberos v5 authentication and ticket-passing routines.
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*
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* $xFreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp$
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*/
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/*
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* Copyright (c) 2002 Daniel Kouril. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "includes.h"
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RCSID("$OpenBSD: auth-krb5.c,v 1.10 2002/11/21 23:03:51 deraadt Exp $");
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RCSID("$FreeBSD$");
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#include "ssh.h"
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#include "ssh1.h"
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#include "packet.h"
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#include "xmalloc.h"
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#include "log.h"
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#include "servconf.h"
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#include "uidswap.h"
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#include "auth.h"
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#ifdef KRB5
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#include <krb5.h>
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#ifndef HEIMDAL
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#define krb5_get_err_text(context,code) error_message(code)
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#endif /* !HEIMDAL */
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extern ServerOptions options;
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static int
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krb5_init(void *context)
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{
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Authctxt *authctxt = (Authctxt *)context;
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krb5_error_code problem;
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static int cleanup_registered = 0;
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if (authctxt->krb5_ctx == NULL) {
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problem = krb5_init_context(&authctxt->krb5_ctx);
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if (problem)
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return (problem);
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krb5_init_ets(authctxt->krb5_ctx);
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}
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if (!cleanup_registered) {
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fatal_add_cleanup(krb5_cleanup_proc, authctxt);
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cleanup_registered = 1;
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}
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return (0);
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}
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/*
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* Try krb5 authentication. server_user is passed for logging purposes
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* only, in auth is received ticket, in client is returned principal
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* from the ticket
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*/
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int
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auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client, krb5_data *reply)
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{
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krb5_error_code problem;
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krb5_principal server;
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krb5_ticket *ticket;
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int fd, ret;
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ret = 0;
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server = NULL;
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ticket = NULL;
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reply->length = 0;
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problem = krb5_init(authctxt);
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if (problem)
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goto err;
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problem = krb5_auth_con_init(authctxt->krb5_ctx,
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&authctxt->krb5_auth_ctx);
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if (problem)
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goto err;
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fd = packet_get_connection_in();
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#ifdef HEIMDAL
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problem = krb5_auth_con_setaddrs_from_fd(authctxt->krb5_ctx,
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authctxt->krb5_auth_ctx, &fd);
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#else
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problem = krb5_auth_con_genaddrs(authctxt->krb5_ctx,
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authctxt->krb5_auth_ctx,fd,
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KRB5_AUTH_CONTEXT_GENERATE_REMOTE_FULL_ADDR |
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KRB5_AUTH_CONTEXT_GENERATE_LOCAL_FULL_ADDR);
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#endif
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if (problem)
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goto err;
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problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
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KRB5_NT_SRV_HST, &server);
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if (problem)
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goto err;
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problem = krb5_rd_req(authctxt->krb5_ctx, &authctxt->krb5_auth_ctx,
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auth, server, NULL, NULL, &ticket);
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if (problem)
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goto err;
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#ifdef HEIMDAL
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problem = krb5_copy_principal(authctxt->krb5_ctx, ticket->client,
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&authctxt->krb5_user);
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#else
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problem = krb5_copy_principal(authctxt->krb5_ctx,
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ticket->enc_part2->client,
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&authctxt->krb5_user);
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#endif
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if (problem)
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goto err;
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/* if client wants mutual auth */
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problem = krb5_mk_rep(authctxt->krb5_ctx, authctxt->krb5_auth_ctx,
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reply);
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if (problem)
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goto err;
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/* Check .k5login authorization now. */
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if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user,
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authctxt->pw->pw_name))
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goto err;
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if (client)
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krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user,
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client);
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ret = 1;
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err:
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if (server)
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krb5_free_principal(authctxt->krb5_ctx, server);
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if (ticket)
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krb5_free_ticket(authctxt->krb5_ctx, ticket);
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if (!ret && reply->length) {
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xfree(reply->data);
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memset(reply, 0, sizeof(*reply));
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}
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if (problem) {
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if (authctxt->krb5_ctx != NULL)
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debug("Kerberos v5 authentication failed: %s",
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krb5_get_err_text(authctxt->krb5_ctx, problem));
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else
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debug("Kerberos v5 authentication failed: %d",
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problem);
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}
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return (ret);
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}
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int
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auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt)
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{
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krb5_error_code problem;
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krb5_ccache ccache = NULL;
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char *pname;
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krb5_creds **creds;
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if (authctxt->pw == NULL || authctxt->krb5_user == NULL)
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return (0);
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temporarily_use_uid(authctxt->pw);
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#ifdef HEIMDAL
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problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, &ccache);
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#else
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{
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char ccname[40];
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int tmpfd;
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snprintf(ccname,sizeof(ccname),"FILE:/tmp/krb5cc_%d_XXXXXX",geteuid());
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if ((tmpfd = mkstemp(ccname+strlen("FILE:")))==-1) {
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log("mkstemp(): %.100s", strerror(errno));
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problem = errno;
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goto fail;
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}
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if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) {
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log("fchmod(): %.100s", strerror(errno));
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close(tmpfd);
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problem = errno;
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goto fail;
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}
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close(tmpfd);
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problem = krb5_cc_resolve(authctxt->krb5_ctx, ccname, &ccache);
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}
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#endif
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if (problem)
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goto fail;
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problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
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authctxt->krb5_user);
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if (problem)
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goto fail;
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#ifdef HEIMDAL
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problem = krb5_rd_cred2(authctxt->krb5_ctx, authctxt->krb5_auth_ctx,
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ccache, tgt);
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if (problem)
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goto fail;
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#else
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problem = krb5_rd_cred(authctxt->krb5_ctx, authctxt->krb5_auth_ctx,
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tgt, &creds, NULL);
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if (problem)
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goto fail;
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problem = krb5_cc_store_cred(authctxt->krb5_ctx, ccache, *creds);
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if (problem)
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goto fail;
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#endif
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authctxt->krb5_fwd_ccache = ccache;
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ccache = NULL;
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authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
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problem = krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user,
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&pname);
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if (problem)
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goto fail;
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debug("Kerberos v5 TGT accepted (%s)", pname);
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restore_uid();
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return (1);
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fail:
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if (problem)
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debug("Kerberos v5 TGT passing failed: %s",
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krb5_get_err_text(authctxt->krb5_ctx, problem));
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if (ccache)
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krb5_cc_destroy(authctxt->krb5_ctx, ccache);
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restore_uid();
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return (0);
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}
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int
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auth_krb5_password(Authctxt *authctxt, const char *password)
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{
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#ifndef HEIMDAL
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krb5_creds creds;
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krb5_principal server;
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char ccname[40];
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int tmpfd;
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#endif
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krb5_error_code problem;
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if (authctxt->pw == NULL)
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return (0);
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temporarily_use_uid(authctxt->pw);
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problem = krb5_init(authctxt);
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if (problem)
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goto out;
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problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name,
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&authctxt->krb5_user);
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if (problem)
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goto out;
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#ifdef HEIMDAL
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problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops,
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&authctxt->krb5_fwd_ccache);
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if (problem)
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goto out;
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problem = krb5_cc_initialize(authctxt->krb5_ctx,
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authctxt->krb5_fwd_ccache, authctxt->krb5_user);
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if (problem)
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goto out;
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restore_uid();
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problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
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authctxt->krb5_fwd_ccache, password, 1, NULL);
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temporarily_use_uid(authctxt->pw);
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if (problem)
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goto out;
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#else
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problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds,
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authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL);
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if (problem)
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goto out;
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problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
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KRB5_NT_SRV_HST, &server);
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if (problem)
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goto out;
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restore_uid();
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problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server,
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NULL, NULL, NULL);
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krb5_free_principal(authctxt->krb5_ctx, server);
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temporarily_use_uid(authctxt->pw);
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if (problem)
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goto out;
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if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user,
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authctxt->pw->pw_name)) {
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problem = -1;
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goto out;
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}
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snprintf(ccname,sizeof(ccname),"FILE:/tmp/krb5cc_%d_XXXXXX",geteuid());
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if ((tmpfd = mkstemp(ccname+strlen("FILE:")))==-1) {
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log("mkstemp(): %.100s", strerror(errno));
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problem = errno;
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goto out;
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}
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if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) {
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log("fchmod(): %.100s", strerror(errno));
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close(tmpfd);
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problem = errno;
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goto out;
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}
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close(tmpfd);
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problem = krb5_cc_resolve(authctxt->krb5_ctx, ccname, &authctxt->krb5_fwd_ccache);
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if (problem)
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goto out;
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problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
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authctxt->krb5_user);
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if (problem)
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goto out;
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problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
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&creds);
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if (problem)
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goto out;
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#endif
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authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
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out:
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restore_uid();
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if (problem) {
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if (authctxt->krb5_ctx != NULL && problem!=-1)
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debug("Kerberos password authentication failed: %s",
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krb5_get_err_text(authctxt->krb5_ctx, problem));
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else
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debug("Kerberos password authentication failed: %d",
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problem);
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krb5_cleanup_proc(authctxt);
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if (options.kerberos_or_local_passwd)
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return (-1);
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else
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return (0);
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}
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return (1);
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}
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void
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krb5_cleanup_proc(void *context)
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{
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Authctxt *authctxt = (Authctxt *)context;
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debug("krb5_cleanup_proc called");
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if (authctxt->krb5_fwd_ccache) {
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krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
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authctxt->krb5_fwd_ccache = NULL;
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}
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if (authctxt->krb5_user) {
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krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
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authctxt->krb5_user = NULL;
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}
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if (authctxt->krb5_auth_ctx) {
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krb5_auth_con_free(authctxt->krb5_ctx,
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authctxt->krb5_auth_ctx);
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authctxt->krb5_auth_ctx = NULL;
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}
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if (authctxt->krb5_ctx) {
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krb5_free_context(authctxt->krb5_ctx);
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authctxt->krb5_ctx = NULL;
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}
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}
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#endif /* KRB5 */
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