1/*
2 * Copyright (c) 1997-2007 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_rd_priv(krb5_context context,
38	     krb5_auth_context auth_context,
39	     const krb5_data *inbuf,
40	     krb5_data *outbuf,
41	     krb5_replay_data *outdata)
42{
43    krb5_error_code ret;
44    KRB_PRIV priv;
45    EncKrbPrivPart part;
46    size_t len;
47    krb5_data plain;
48    krb5_keyblock *key;
49    krb5_crypto crypto;
50
51    krb5_data_zero(outbuf);
52
53    if ((auth_context->flags &
54	 (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE)))
55    {
56	if (outdata == NULL) {
57	    krb5_clear_error_message (context);
58	    return KRB5_RC_REQUIRED; /* XXX better error, MIT returns this */
59	}
60	/* if these fields are not present in the priv-part, silently
61           return zero */
62	memset(outdata, 0, sizeof(*outdata));
63    }
64
65    memset(&priv, 0, sizeof(priv));
66    ret = decode_KRB_PRIV (inbuf->data, inbuf->length, &priv, &len);
67    if (ret) {
68	krb5_clear_error_message (context);
69	goto failure;
70    }
71    if (priv.pvno != 5) {
72	krb5_clear_error_message (context);
73	ret = KRB5KRB_AP_ERR_BADVERSION;
74	goto failure;
75    }
76    if (priv.msg_type != krb_priv) {
77	krb5_clear_error_message (context);
78	ret = KRB5KRB_AP_ERR_MSG_TYPE;
79	goto failure;
80    }
81
82    if (auth_context->remote_subkey)
83	key = auth_context->remote_subkey;
84    else if (auth_context->local_subkey)
85	key = auth_context->local_subkey;
86    else
87	key = auth_context->keyblock;
88
89    ret = krb5_crypto_init(context, key, 0, &crypto);
90    if (ret)
91	goto failure;
92    ret = krb5_decrypt_EncryptedData(context,
93				     crypto,
94				     KRB5_KU_KRB_PRIV,
95				     &priv.enc_part,
96				     &plain);
97    krb5_crypto_destroy(context, crypto);
98    if (ret)
99	goto failure;
100
101    ret = decode_EncKrbPrivPart (plain.data, plain.length, &part, &len);
102    krb5_data_free (&plain);
103    if (ret) {
104	krb5_clear_error_message (context);
105	goto failure;
106    }
107
108    /* check sender address */
109
110    if (part.s_address
111	&& auth_context->remote_address
112	&& !krb5_address_compare (context,
113				  auth_context->remote_address,
114				  part.s_address)) {
115	krb5_clear_error_message (context);
116	ret = KRB5KRB_AP_ERR_BADADDR;
117	goto failure_part;
118    }
119
120    /* check receiver address */
121
122    if (part.r_address
123	&& auth_context->local_address
124	&& !krb5_address_compare (context,
125				  auth_context->local_address,
126				  part.r_address)) {
127	krb5_clear_error_message (context);
128	ret = KRB5KRB_AP_ERR_BADADDR;
129	goto failure_part;
130    }
131
132    /* check timestamp */
133    if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
134	krb5_timestamp sec;
135
136	krb5_timeofday (context, &sec);
137	if (part.timestamp == NULL ||
138	    part.usec      == NULL ||
139	    krb5_time_abs(*part.timestamp, sec) > context->max_skew) {
140	    krb5_clear_error_message (context);
141	    ret = KRB5KRB_AP_ERR_SKEW;
142	    goto failure_part;
143	}
144    }
145
146    /* XXX - check replay cache */
147
148    /* check sequence number. since MIT krb5 cannot generate a sequence
149       number of zero but instead generates no sequence number, we accept that
150    */
151
152    if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
153	if ((part.seq_number == NULL
154	     && auth_context->remote_seqnumber != 0)
155	    || (part.seq_number != NULL
156		&& *part.seq_number != auth_context->remote_seqnumber)) {
157	    krb5_clear_error_message (context);
158	    ret = KRB5KRB_AP_ERR_BADORDER;
159	    goto failure_part;
160	}
161	auth_context->remote_seqnumber++;
162    }
163
164    ret = krb5_data_copy (outbuf, part.user_data.data, part.user_data.length);
165    if (ret)
166	goto failure_part;
167
168    if ((auth_context->flags &
169	 (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE))) {
170	if(part.timestamp)
171	    outdata->timestamp = *part.timestamp;
172	if(part.usec)
173	    outdata->usec = *part.usec;
174	if(part.seq_number)
175	    outdata->seq = *part.seq_number;
176    }
177
178  failure_part:
179    free_EncKrbPrivPart (&part);
180
181  failure:
182    free_KRB_PRIV (&priv);
183    return ret;
184}
185