1/*
2 * Copyright (c) 1997 - 2003 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * 3. Neither the name of the Institute nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include "krb5_locl.h"
35
36KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
37krb5_mk_safe(krb5_context context,
38	     krb5_auth_context auth_context,
39	     const krb5_data *userdata,
40	     krb5_data *outbuf,
41	     krb5_replay_data *outdata)
42{
43    krb5_error_code ret;
44    KRB_SAFE s;
45    u_char *buf = NULL;
46    size_t buf_size;
47    size_t len = 0;
48    krb5_crypto crypto;
49    krb5_keyblock *key;
50    krb5_replay_data rdata;
51
52    if ((auth_context->flags &
53	 (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE)) &&
54	outdata == NULL)
55	return KRB5_RC_REQUIRED; /* XXX better error, MIT returns this */
56
57    if (auth_context->local_subkey)
58	key = auth_context->local_subkey;
59    else if (auth_context->remote_subkey)
60	key = auth_context->remote_subkey;
61    else
62	key = auth_context->keyblock;
63
64    s.pvno = 5;
65    s.msg_type = krb_safe;
66
67    memset(&rdata, 0, sizeof(rdata));
68
69    s.safe_body.user_data = *userdata;
70
71    krb5_us_timeofday (context, &rdata.timestamp, &rdata.usec);
72
73    if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
74	s.safe_body.timestamp  = &rdata.timestamp;
75	s.safe_body.usec       = &rdata.usec;
76    } else {
77	s.safe_body.timestamp  = NULL;
78	s.safe_body.usec       = NULL;
79    }
80
81    if (auth_context->flags & KRB5_AUTH_CONTEXT_RET_TIME) {
82	outdata->timestamp = rdata.timestamp;
83	outdata->usec = rdata.usec;
84    }
85
86    if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
87	rdata.seq = auth_context->local_seqnumber;
88	s.safe_body.seq_number = &rdata.seq;
89    } else
90	s.safe_body.seq_number = NULL;
91
92    if (auth_context->flags & KRB5_AUTH_CONTEXT_RET_SEQUENCE)
93	outdata->seq = auth_context->local_seqnumber;
94
95    s.safe_body.s_address = auth_context->local_address;
96    s.safe_body.r_address = auth_context->remote_address;
97
98    s.cksum.cksumtype       = 0;
99    s.cksum.checksum.data   = NULL;
100    s.cksum.checksum.length = 0;
101
102    ASN1_MALLOC_ENCODE(KRB_SAFE, buf, buf_size, &s, &len, ret);
103    if (ret)
104	return ret;
105    if(buf_size != len)
106	krb5_abortx(context, "internal error in ASN.1 encoder");
107    ret = krb5_crypto_init(context, key, 0, &crypto);
108    if (ret) {
109	free (buf);
110	return ret;
111    }
112    ret = krb5_create_checksum(context,
113			       crypto,
114			       KRB5_KU_KRB_SAFE_CKSUM,
115			       0,
116			       buf,
117			       len,
118			       &s.cksum);
119    krb5_crypto_destroy(context, crypto);
120    if (ret) {
121	free (buf);
122	return ret;
123    }
124
125    free(buf);
126    ASN1_MALLOC_ENCODE(KRB_SAFE, buf, buf_size, &s, &len, ret);
127    free_Checksum (&s.cksum);
128    if(ret)
129	return ret;
130    if(buf_size != len)
131	krb5_abortx(context, "internal error in ASN.1 encoder");
132
133    outbuf->length = len;
134    outbuf->data   = buf;
135    if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE)
136	auth_context->local_seqnumber =
137	    (auth_context->local_seqnumber + 1) & 0xFFFFFFFF;
138    return 0;
139}
140