1 /*        $NetBSD: mk_rep.c,v 1.2 2017/01/28 21:31:49 christos Exp $  */
2 
3 /*
4  * Copyright (c) 1997 - 2003 Kungliga Tekniska Högskolan
5  * (Royal Institute of Technology, Stockholm, Sweden).
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  *
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * 3. Neither the name of the Institute nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include "krb5_locl.h"
37 
38 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_mk_rep(krb5_context context,krb5_auth_context auth_context,krb5_data * outbuf)39 krb5_mk_rep(krb5_context context,
40               krb5_auth_context auth_context,
41               krb5_data *outbuf)
42 {
43     krb5_error_code ret;
44     AP_REP ap;
45     EncAPRepPart body;
46     u_char *buf = NULL;
47     size_t buf_size;
48     size_t len = 0;
49     krb5_crypto crypto;
50 
51     ap.pvno = 5;
52     ap.msg_type = krb_ap_rep;
53 
54     memset (&body, 0, sizeof(body));
55 
56     body.ctime = auth_context->authenticator->ctime;
57     body.cusec = auth_context->authenticator->cusec;
58     if (auth_context->flags & KRB5_AUTH_CONTEXT_USE_SUBKEY) {
59           if (auth_context->local_subkey == NULL) {
60               ret = krb5_auth_con_generatelocalsubkey(context,
61                                                                 auth_context,
62                                                                 auth_context->keyblock);
63               if(ret) {
64                     free_EncAPRepPart(&body);
65                     return ret;
66               }
67           }
68           ret = krb5_copy_keyblock(context, auth_context->local_subkey,
69                                          &body.subkey);
70           if (ret) {
71               free_EncAPRepPart(&body);
72               return krb5_enomem(context);
73           }
74     } else
75           body.subkey = NULL;
76     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
77           if(auth_context->local_seqnumber == 0)
78               krb5_generate_seq_number (context,
79                                               auth_context->keyblock,
80                                               &auth_context->local_seqnumber);
81           ALLOC(body.seq_number, 1);
82           if (body.seq_number == NULL) {
83               free_EncAPRepPart(&body);
84               return krb5_enomem(context);
85           }
86           *(body.seq_number) = auth_context->local_seqnumber;
87     } else
88           body.seq_number = NULL;
89 
90     ap.enc_part.etype = auth_context->keyblock->keytype;
91     ap.enc_part.kvno  = NULL;
92 
93     ASN1_MALLOC_ENCODE(EncAPRepPart, buf, buf_size, &body, &len, ret);
94     free_EncAPRepPart (&body);
95     if(ret)
96           return ret;
97     if (buf_size != len)
98           krb5_abortx(context, "internal error in ASN.1 encoder");
99     ret = krb5_crypto_init(context, auth_context->keyblock,
100                                  0 /* ap.enc_part.etype */, &crypto);
101     if (ret) {
102           free (buf);
103           return ret;
104     }
105     ret = krb5_encrypt (context,
106                               crypto,
107                               KRB5_KU_AP_REQ_ENC_PART,
108                               buf + buf_size - len,
109                               len,
110                               &ap.enc_part.cipher);
111     krb5_crypto_destroy(context, crypto);
112     free(buf);
113     if (ret)
114           return ret;
115 
116     ASN1_MALLOC_ENCODE(AP_REP, outbuf->data, outbuf->length, &ap, &len, ret);
117     if (ret == 0 && outbuf->length != len)
118           krb5_abortx(context, "internal error in ASN.1 encoder");
119     free_AP_REP (&ap);
120     return ret;
121 }
122