1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
|
/*
* lib/krb5/krb/sendauth.c
*
* Copyright 1991 by the Massachusetts Institute of Technology.
* All Rights Reserved.
*
* Export of this software from the United States of America may
* require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. Furthermore if you modify this software you must label
* your software as modified software and not distribute it in such a
* fashion that it might be confused with the original M.I.T. software.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
*
* convenience sendauth/recvauth functions
*/
#define NEED_SOCKETS
#include "k5-int.h"
#include "com_err.h"
#include "auth_con.h"
#include <errno.h>
#include <stdio.h>
#include <string.h>
#ifndef GETPEERNAME_ARG2_TYPE
#define GETPEERNAME_ARG2_TYPE struct sockaddr
#endif
#ifndef GETPEERNAME_ARG3_TYPE
#define GETPEERNAME_ARG3_TYPE size_t
#endif
#ifndef GETSOCKNAME_ARG2_TYPE
#define GETSOCKNAME_ARG2_TYPE struct sockaddr
#endif
#ifndef GETSOCKNAME_ARG3_TYPE
#define GETSOCKNAME_ARG3_TYPE size_t
#endif
static const char sendauth_version[] = "KRB5_SENDAUTH_V1.0";
krb5_error_code KRB5_CALLCONV
krb5_sendauth(krb5_context context, krb5_auth_context *auth_context, krb5_pointer fd, char *appl_version, krb5_principal client, krb5_principal server, krb5_flags ap_req_options, krb5_data *in_data, krb5_creds *in_creds, krb5_ccache ccache, krb5_error **error, krb5_ap_rep_enc_part **rep_result, krb5_creds **out_creds)
{
krb5_octet result;
krb5_creds creds;
krb5_creds * credsp = NULL;
krb5_creds * credspout = NULL;
krb5_error_code retval = 0;
krb5_data inbuf, outbuf;
int len;
krb5_ccache use_ccache = 0;
if (error)
*error = 0;
/*
* First, send over the length of the sendauth version string;
* then, we send over the sendauth version. Next, we send
* over the length of the application version strings followed
* by the string itself.
*/
outbuf.length = strlen(sendauth_version) + 1;
outbuf.data = (char *) sendauth_version;
if ((retval = krb5_write_message(context, fd, &outbuf)))
return(retval);
outbuf.length = strlen(appl_version) + 1;
outbuf.data = appl_version;
if ((retval = krb5_write_message(context, fd, &outbuf)))
return(retval);
/*
* Now, read back a byte: 0 means no error, 1 means bad sendauth
* version, 2 means bad application version
*/
if ((len = krb5_net_read(context, *((int *) fd), (char *)&result, 1)) != 1)
return((len < 0) ? errno : ECONNABORTED);
if (result == 1)
return(KRB5_SENDAUTH_BADAUTHVERS);
else if (result == 2)
return(KRB5_SENDAUTH_BADAPPLVERS);
else if (result != 0)
return(KRB5_SENDAUTH_BADRESPONSE);
/*
* We're finished with the initial negotiations; let's get and
* send over the authentication header. (The AP_REQ message)
*/
/*
* If no credentials were provided, try getting it from the
* credentials cache.
*/
memset((char *)&creds, 0, sizeof(creds));
/*
* See if we need to access the credentials cache
*/
if (!in_creds || !in_creds->ticket.length) {
if (ccache)
use_ccache = ccache;
else if ((retval = krb5int_cc_default(context, &use_ccache)))
goto error_return;
}
if (!in_creds) {
if ((retval = krb5_copy_principal(context, server,
&creds.server)))
goto error_return;
if (client)
retval = krb5_copy_principal(context, client,
&creds.client);
else
retval = krb5_cc_get_principal(context, use_ccache,
&creds.client);
if (retval) {
krb5_free_principal(context, creds.server);
goto error_return;
}
/* creds.times.endtime = 0; -- memset 0 takes care of this
zero means "as long as possible" */
/* creds.keyblock.enctype = 0; -- as well as this.
zero means no session enctype
preference */
in_creds = &creds;
}
if (!in_creds->ticket.length) {
if ((retval = krb5_get_credentials(context, 0,
use_ccache, in_creds, &credsp)))
goto error_return;
credspout = credsp;
} else {
credsp = in_creds;
}
if (ap_req_options & AP_OPTS_USE_SUBKEY) {
/* Provide some more fodder for random number code.
This isn't strong cryptographically; the point here is
not to guarantee randomness, but to make it less likely
that multiple sessions could pick the same subkey. */
char rnd_data[1024];
GETPEERNAME_ARG3_TYPE len2;
krb5_data d;
d.length = sizeof (rnd_data);
d.data = rnd_data;
len2 = sizeof (rnd_data);
if (getpeername (*(int*)fd, (GETPEERNAME_ARG2_TYPE *) rnd_data,
&len2) == 0) {
d.length = len2;
(void) krb5_c_random_add_entropy (context, KRB5_C_RANDSOURCE_EXTERNAL_PROTOCOL, &d);
}
len2 = sizeof (rnd_data);
if (getsockname (*(int*)fd, (GETSOCKNAME_ARG2_TYPE *) rnd_data,
&len2) == 0) {
d.length = len2;
(void) krb5_c_random_add_entropy (context, KRB5_C_RANDSOURCE_EXTERNAL_PROTOCOL, &d);
}
}
if ((retval = krb5_mk_req_extended(context, auth_context,
ap_req_options, in_data, credsp,
&outbuf)))
goto error_return;
/*
* First write the length of the AP_REQ message, then write
* the message itself.
*/
retval = krb5_write_message(context, fd, &outbuf);
free(outbuf.data);
if (retval)
goto error_return;
/*
* Now, read back a message. If it was a null message (the
* length was zero) then there was no error. If not, we the
* authentication was rejected, and we need to return the
* error structure.
*/
if ((retval = krb5_read_message(context, fd, &inbuf)))
goto error_return;
if (inbuf.length) {
if (error) {
if ((retval = krb5_rd_error(context, &inbuf, error))) {
krb5_xfree(inbuf.data);
goto error_return;
}
}
retval = KRB5_SENDAUTH_REJECTED;
krb5_xfree(inbuf.data);
goto error_return;
}
/*
* If we asked for mutual authentication, we should now get a
* length field, followed by a AP_REP message
*/
if ((ap_req_options & AP_OPTS_MUTUAL_REQUIRED)) {
krb5_ap_rep_enc_part *repl = 0;
if ((retval = krb5_read_message(context, fd, &inbuf)))
goto error_return;
if ((retval = krb5_rd_rep(context, *auth_context, &inbuf,
&repl))) {
if (repl)
krb5_free_ap_rep_enc_part(context, repl);
krb5_xfree(inbuf.data);
goto error_return;
}
krb5_xfree(inbuf.data);
/*
* If the user wants to look at the AP_REP message,
* copy it for him
*/
if (rep_result)
*rep_result = repl;
else
krb5_free_ap_rep_enc_part(context, repl);
}
retval = 0; /* Normal return */
if (out_creds) {
*out_creds = credsp;
credspout = NULL;
}
error_return:
krb5_free_cred_contents(context, &creds);
if (credspout != NULL)
krb5_free_creds(context, credspout);
if (!ccache && use_ccache)
krb5_cc_close(context, use_ccache);
return(retval);
}
|
