1 /*	$NetBSD: mk_safe.c,v 1.1.1.1 2011/04/13 18:15:36 elric 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
39 krb5_mk_safe(krb5_context context,
40 	     krb5_auth_context auth_context,
41 	     const krb5_data *userdata,
42 	     krb5_data *outbuf,
43 	     krb5_replay_data *outdata)
44 {
45     krb5_error_code ret;
46     KRB_SAFE s;
47     u_char *buf = NULL;
48     size_t buf_size;
49     size_t len;
50     krb5_crypto crypto;
51     krb5_keyblock *key;
52     krb5_replay_data rdata;
53 
54     if ((auth_context->flags &
55 	 (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE)) &&
56 	outdata == NULL)
57 	return KRB5_RC_REQUIRED; /* XXX better error, MIT returns this */
58 
59     if (auth_context->local_subkey)
60 	key = auth_context->local_subkey;
61     else if (auth_context->remote_subkey)
62 	key = auth_context->remote_subkey;
63     else
64 	key = auth_context->keyblock;
65 
66     s.pvno = 5;
67     s.msg_type = krb_safe;
68 
69     memset(&rdata, 0, sizeof(rdata));
70 
71     s.safe_body.user_data = *userdata;
72 
73     krb5_us_timeofday (context, &rdata.timestamp, &rdata.usec);
74 
75     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
76 	s.safe_body.timestamp  = &rdata.timestamp;
77 	s.safe_body.usec       = &rdata.usec;
78     } else {
79 	s.safe_body.timestamp  = NULL;
80 	s.safe_body.usec       = NULL;
81     }
82 
83     if (auth_context->flags & KRB5_AUTH_CONTEXT_RET_TIME) {
84 	outdata->timestamp = rdata.timestamp;
85 	outdata->usec = rdata.usec;
86     }
87 
88     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
89 	rdata.seq = auth_context->local_seqnumber;
90 	s.safe_body.seq_number = &rdata.seq;
91     } else
92 	s.safe_body.seq_number = NULL;
93 
94     if (auth_context->flags & KRB5_AUTH_CONTEXT_RET_SEQUENCE)
95 	outdata->seq = auth_context->local_seqnumber;
96 
97     s.safe_body.s_address = auth_context->local_address;
98     s.safe_body.r_address = auth_context->remote_address;
99 
100     s.cksum.cksumtype       = 0;
101     s.cksum.checksum.data   = NULL;
102     s.cksum.checksum.length = 0;
103 
104     ASN1_MALLOC_ENCODE(KRB_SAFE, buf, buf_size, &s, &len, ret);
105     if (ret)
106 	return ret;
107     if(buf_size != len)
108 	krb5_abortx(context, "internal error in ASN.1 encoder");
109     ret = krb5_crypto_init(context, key, 0, &crypto);
110     if (ret) {
111 	free (buf);
112 	return ret;
113     }
114     ret = krb5_create_checksum(context,
115 			       crypto,
116 			       KRB5_KU_KRB_SAFE_CKSUM,
117 			       0,
118 			       buf,
119 			       len,
120 			       &s.cksum);
121     krb5_crypto_destroy(context, crypto);
122     if (ret) {
123 	free (buf);
124 	return ret;
125     }
126 
127     free(buf);
128     ASN1_MALLOC_ENCODE(KRB_SAFE, buf, buf_size, &s, &len, ret);
129     free_Checksum (&s.cksum);
130     if(ret)
131 	return ret;
132     if(buf_size != len)
133 	krb5_abortx(context, "internal error in ASN.1 encoder");
134 
135     outbuf->length = len;
136     outbuf->data   = buf;
137     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE)
138 	auth_context->local_seqnumber =
139 	    (auth_context->local_seqnumber + 1) & 0xFFFFFFFF;
140     return 0;
141 }
142