aboutsummaryrefslogtreecommitdiffstats
path: root/src/lib/krb5/krb/fwd_tgt.c
blob: a217d4c240014de60c14b9eb8a09bdf1ed0f3291 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* lib/krb5/krb/fwd_tgt.c Definition of krb5_fwd_tgt_creds() routine */
/*
 * Copyright 1995 by the Massachusetts Institute of Technology.
 * All Rights Reserved.
 *
 * Export of this software from the United States of America may
 *   require a specific license from the United States Government.
 *   It is the responsibility of any person or organization contemplating
 *   export to obtain such a license before exporting.
 *
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of M.I.T. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  Furthermore if you modify this software you must label
 * your software as modified software and not distribute it in such a
 * fashion that it might be confused with the original M.I.T. software.
 * M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 */

#include "k5-int.h"
#ifdef HAVE_MEMORY_H
#include <memory.h>
#endif
#include "int-proto.h"
#include "os-proto.h"

/* helper function: convert flags to necessary KDC options */
#define flags2options(flags) (flags & KDC_TKT_COMMON_MASK)

/* Get a TGT for use at the remote host */
krb5_error_code KRB5_CALLCONV
krb5_fwd_tgt_creds(krb5_context context, krb5_auth_context auth_context,
                   char *rhost, krb5_principal client, krb5_principal server,
                   krb5_ccache cc, int forwardable, krb5_data *outbuf)
/* Should forwarded TGT also be forwardable? */
{
    krb5_replay_data replaydata;
    krb5_data * scratch = 0;
    krb5_address **addrs = NULL;
    krb5_error_code retval;
    krb5_creds creds, tgt;
    krb5_creds *pcreds;
    krb5_flags kdcoptions;
    int close_cc = 0;
    int free_rhost = 0;
    krb5_enctype enctype = 0;
    krb5_keyblock *session_key;
    krb5_boolean old_use_conf_ktypes = context->use_conf_ktypes;

    memset(&creds, 0, sizeof(creds));
    memset(&tgt, 0, sizeof(creds));

    if (cc == 0) {
        if ((retval = krb5int_cc_default(context, &cc)))
            goto errout;
        close_cc = 1;
    }
    retval = krb5_auth_con_getkey (context, auth_context, &session_key);
    if (retval)
        goto errout;
    if (session_key) {
        enctype = session_key->enctype;
        krb5_free_keyblock (context, session_key);
        session_key = NULL;
    } else if (server) { /* must server be non-NULL when rhost is given? */
        /* Try getting credentials to see what the remote side supports.
           Not bulletproof, just a heuristic.  */
        krb5_creds in, *out = 0;
        memset (&in, 0, sizeof(in));

        retval = krb5_copy_principal (context, server, &in.server);
        if (retval)
            goto punt;
        retval = krb5_copy_principal (context, client, &in.client);
        if (retval)
            goto punt;
        retval = krb5_get_credentials (context, 0, cc, &in, &out);
        if (retval)
            goto punt;
        /* Got the credentials.  Okay, now record the enctype and
           throw them away.  */
        enctype = out->keyblock.enctype;
        krb5_free_creds (context, out);
    punt:
        krb5_free_cred_contents (context, &in);
    }

    if ((retval = krb5_copy_principal(context, client, &creds.client)))
        goto errout;

    retval = krb5int_tgtname(context, &client->realm, &client->realm,
                             &creds.server);
    if (retval)
        goto errout;

    /* fetch tgt directly from cache */
    context->use_conf_ktypes = 1;
    retval = krb5_cc_retrieve_cred (context, cc, KRB5_TC_SUPPORTED_KTYPES,
                                    &creds, &tgt);
    context->use_conf_ktypes = old_use_conf_ktypes;
    if (retval)
        goto errout;

    /* tgt->client must be equal to creds.client */
    if (!krb5_principal_compare(context, tgt.client, creds.client)) {
        retval = KRB5_PRINC_NOMATCH;
        goto errout;
    }

    if (!tgt.ticket.length) {
        retval = KRB5_NO_TKT_SUPPLIED;
        goto errout;
    }

    if (tgt.addresses && *tgt.addresses) {
        if (rhost == NULL) {
            if (server->type != KRB5_NT_SRV_HST) {
                retval = KRB5_FWD_BAD_PRINCIPAL;
                goto errout;
            }

            if (server->length < 2){
                retval = KRB5_CC_BADNAME;
                goto errout;
            }

            rhost = k5memdup0(server->data[1].data, server->data[1].length,
                              &retval);
            if (rhost == NULL)
                goto errout;
            free_rhost = 1;
        }

        retval = k5_os_hostaddr(context, rhost, &addrs);
        if (retval)
            goto errout;
    }

    creds.keyblock.enctype = enctype;
    creds.times = tgt.times;
    creds.times.starttime = 0;
    kdcoptions = flags2options(tgt.ticket_flags)|KDC_OPT_FORWARDED;

    if (!forwardable) /* Reset KDC_OPT_FORWARDABLE */
        kdcoptions &= ~(KDC_OPT_FORWARDABLE);

    if ((retval = krb5_get_cred_via_tkt(context, &tgt, kdcoptions,
                                        addrs, &creds, &pcreds))) {
        if (enctype) {
            creds.keyblock.enctype = 0;
            if ((retval = krb5_get_cred_via_tkt(context, &tgt, kdcoptions,
                                                addrs, &creds, &pcreds)))
                goto errout;
        }
        else goto errout;
    }
    retval = krb5_mk_1cred(context, auth_context, pcreds,
                           &scratch, &replaydata);
    krb5_free_creds(context, pcreds);

    if (retval) {
        if (scratch)
            krb5_free_data(context, scratch);
    } else {
        *outbuf = *scratch;
        free(scratch);
    }

errout:
    if (addrs)
        krb5_free_addresses(context, addrs);
    if (close_cc)
        krb5_cc_close(context, cc);
    if (free_rhost)
        free(rhost);
    krb5_free_cred_contents(context, &creds);
    krb5_free_cred_contents(context, &tgt);
    return retval;
}