xref: /freebsd/crypto/heimdal/lib/krb5/rd_priv.c (revision 7aa383846770374466b1dcb2cefd71bde9acf463)
1 /*
2  * Copyright (c) 1997-2007 Kungliga Tekniska H�gskolan
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 
36 RCSID("$Id: rd_priv.c 21751 2007-07-31 20:42:20Z lha $");
37 
38 krb5_error_code KRB5_LIB_FUNCTION
39 krb5_rd_priv(krb5_context context,
40 	     krb5_auth_context auth_context,
41 	     const krb5_data *inbuf,
42 	     krb5_data *outbuf,
43 	     krb5_replay_data *outdata)
44 {
45     krb5_error_code ret;
46     KRB_PRIV priv;
47     EncKrbPrivPart part;
48     size_t len;
49     krb5_data plain;
50     krb5_keyblock *key;
51     krb5_crypto crypto;
52 
53     if (outbuf)
54 	krb5_data_zero(outbuf);
55 
56     if ((auth_context->flags &
57 	 (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE)) &&
58 	outdata == NULL) {
59 	krb5_clear_error_string (context);
60 	return KRB5_RC_REQUIRED; /* XXX better error, MIT returns this */
61     }
62 
63     memset(&priv, 0, sizeof(priv));
64     ret = decode_KRB_PRIV (inbuf->data, inbuf->length, &priv, &len);
65     if (ret) {
66 	krb5_clear_error_string (context);
67 	goto failure;
68     }
69     if (priv.pvno != 5) {
70 	krb5_clear_error_string (context);
71 	ret = KRB5KRB_AP_ERR_BADVERSION;
72 	goto failure;
73     }
74     if (priv.msg_type != krb_priv) {
75 	krb5_clear_error_string (context);
76 	ret = KRB5KRB_AP_ERR_MSG_TYPE;
77 	goto failure;
78     }
79 
80     if (auth_context->remote_subkey)
81 	key = auth_context->remote_subkey;
82     else if (auth_context->local_subkey)
83 	key = auth_context->local_subkey;
84     else
85 	key = auth_context->keyblock;
86 
87     ret = krb5_crypto_init(context, key, 0, &crypto);
88     if (ret)
89 	goto failure;
90     ret = krb5_decrypt_EncryptedData(context,
91 				     crypto,
92 				     KRB5_KU_KRB_PRIV,
93 				     &priv.enc_part,
94 				     &plain);
95     krb5_crypto_destroy(context, crypto);
96     if (ret)
97 	goto failure;
98 
99     ret = decode_EncKrbPrivPart (plain.data, plain.length, &part, &len);
100     krb5_data_free (&plain);
101     if (ret) {
102 	krb5_clear_error_string (context);
103 	goto failure;
104     }
105 
106     /* check sender address */
107 
108     if (part.s_address
109 	&& auth_context->remote_address
110 	&& !krb5_address_compare (context,
111 				  auth_context->remote_address,
112 				  part.s_address)) {
113 	krb5_clear_error_string (context);
114 	ret = KRB5KRB_AP_ERR_BADADDR;
115 	goto failure_part;
116     }
117 
118     /* check receiver address */
119 
120     if (part.r_address
121 	&& auth_context->local_address
122 	&& !krb5_address_compare (context,
123 				  auth_context->local_address,
124 				  part.r_address)) {
125 	krb5_clear_error_string (context);
126 	ret = KRB5KRB_AP_ERR_BADADDR;
127 	goto failure_part;
128     }
129 
130     /* check timestamp */
131     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
132 	krb5_timestamp sec;
133 
134 	krb5_timeofday (context, &sec);
135 	if (part.timestamp == NULL ||
136 	    part.usec      == NULL ||
137 	    abs(*part.timestamp - sec) > context->max_skew) {
138 	    krb5_clear_error_string (context);
139 	    ret = KRB5KRB_AP_ERR_SKEW;
140 	    goto failure_part;
141 	}
142     }
143 
144     /* XXX - check replay cache */
145 
146     /* check sequence number. since MIT krb5 cannot generate a sequence
147        number of zero but instead generates no sequence number, we accept that
148     */
149 
150     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
151 	if ((part.seq_number == NULL
152 	     && auth_context->remote_seqnumber != 0)
153 	    || (part.seq_number != NULL
154 		&& *part.seq_number != auth_context->remote_seqnumber)) {
155 	    krb5_clear_error_string (context);
156 	    ret = KRB5KRB_AP_ERR_BADORDER;
157 	    goto failure_part;
158 	}
159 	auth_context->remote_seqnumber++;
160     }
161 
162     ret = krb5_data_copy (outbuf, part.user_data.data, part.user_data.length);
163     if (ret)
164 	goto failure_part;
165 
166     if ((auth_context->flags &
167 	 (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE))) {
168 	/* if these fields are not present in the priv-part, silently
169            return zero */
170 	memset(outdata, 0, sizeof(*outdata));
171 	if(part.timestamp)
172 	    outdata->timestamp = *part.timestamp;
173 	if(part.usec)
174 	    outdata->usec = *part.usec;
175 	if(part.seq_number)
176 	    outdata->seq = *part.seq_number;
177     }
178 
179   failure_part:
180     free_EncKrbPrivPart (&part);
181 
182   failure:
183     free_KRB_PRIV (&priv);
184     return ret;
185 }
186