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
36 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_priv(krb5_context context,krb5_auth_context auth_context,const krb5_data * inbuf,krb5_data * outbuf,krb5_replay_data * outdata)37 krb5_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 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