source: branches/samba-3.0/source/lib/afs.c@ 161

Last change on this file since 161 was 1, checked in by Paul Smedley, 18 years ago

Initial code import
File size: 7.0 KB
Line 
1/*
2 * Unix SMB/CIFS implementation.
3 * Generate AFS tickets
4 * Copyright (C) Volker Lendecke 2003
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
21#include "includes.h"
22
23#ifdef WITH_FAKE_KASERVER
24
25#define NO_ASN1_TYPEDEFS 1
26
27#include <afs/stds.h>
28#include <afs/afs.h>
29#include <afs/auth.h>
30#include <afs/venus.h>
31#include <asm/unistd.h>
32#include <openssl/des.h>
33
34struct ClearToken {
35 uint32 AuthHandle;
36 char HandShakeKey[8];
37 uint32 ViceId;
38 uint32 BeginTimestamp;
39 uint32 EndTimestamp;
40};
41
42static char *afs_encode_token(const char *cell, const DATA_BLOB ticket,
43 const struct ClearToken *ct)
44{
45 char *base64_ticket;
46 char *result;
47
48 DATA_BLOB key = data_blob(ct->HandShakeKey, 8);
49 char *base64_key;
50
51 base64_ticket = base64_encode_data_blob(ticket);
52 if (base64_ticket == NULL)
53 return NULL;
54
55 base64_key = base64_encode_data_blob(key);
56 if (base64_key == NULL) {
57 free(base64_ticket);
58 return NULL;
59 }
60
61 asprintf(&result, "%s\n%u\n%s\n%u\n%u\n%u\n%s\n", cell,
62 ct->AuthHandle, base64_key, ct->ViceId, ct->BeginTimestamp,
63 ct->EndTimestamp, base64_ticket);
64
65 DEBUG(10, ("Got ticket string:\n%s\n", result));
66
67 free(base64_ticket);
68 free(base64_key);
69
70 return result;
71}
72
73/* Create a ClearToken and an encrypted ticket. ClearToken has not yet the
74 * ViceId set, this should be set by the caller. */
75
76static BOOL afs_createtoken(const char *username, const char *cell,
77 DATA_BLOB *ticket, struct ClearToken *ct)
78{
79 fstring clear_ticket;
80 char *p = clear_ticket;
81 uint32 len;
82 uint32 now;
83
84 struct afs_key key;
85 des_key_schedule key_schedule;
86
87 if (!secrets_init())
88 return False;
89
90 if (!secrets_fetch_afs_key(cell, &key)) {
91 DEBUG(1, ("Could not fetch AFS service key\n"));
92 return False;
93 }
94
95 ct->AuthHandle = key.kvno;
96
97 /* Build the ticket. This is going to be encrypted, so in our
98 way we fill in ct while we still have the unencrypted
99 form. */
100
101 p = clear_ticket;
102
103 /* The byte-order */
104 *p = 1;
105 p += 1;
106
107 /* "Alice", the client username */
108 strncpy(p, username, sizeof(clear_ticket)-PTR_DIFF(p,clear_ticket)-1);
109 p += strlen(p)+1;
110 strncpy(p, "", sizeof(clear_ticket)-PTR_DIFF(p,clear_ticket)-1);
111 p += strlen(p)+1;
112 strncpy(p, cell, sizeof(clear_ticket)-PTR_DIFF(p,clear_ticket)-1);
113 p += strlen(p)+1;
114
115 /* Alice's network layer address. At least Openafs-1.2.10
116 ignores this, so we fill in a dummy value here. */
117 SIVAL(p, 0, 0);
118 p += 4;
119
120 /* We need to create a session key */
121 generate_random_buffer(p, 8);
122
123 /* Our client code needs the the key in the clear, it does not
124 know the server-key ... */
125 memcpy(ct->HandShakeKey, p, 8);
126
127 p += 8;
128
129 /* This is a kerberos 4 life time. The life time is expressed
130 * in units of 5 minute intervals up to 38400 seconds, after
131 * that a table is used up to lifetime 0xBF. Values between
132 * 0xC0 and 0xFF is undefined. 0xFF is defined to be the
133 * infinite time that never expire.
134 *
135 * So here we cheat and use the infinite time */
136 *p = 255;
137 p += 1;
138
139 /* Ticket creation time */
140 now = time(NULL);
141 SIVAL(p, 0, now);
142 ct->BeginTimestamp = now;
143
144 if(lp_afs_token_lifetime() == 0)
145 ct->EndTimestamp = NEVERDATE;
146 else
147 ct->EndTimestamp = now + lp_afs_token_lifetime();
148
149 if (((ct->EndTimestamp - ct->BeginTimestamp) & 1) == 1) {
150 ct->BeginTimestamp += 1; /* Lifetime must be even */
151 }
152 p += 4;
153
154 /* And here comes Bob's name and instance, in this case the
155 AFS server. */
156 strncpy(p, "afs", sizeof(clear_ticket)-PTR_DIFF(p,clear_ticket)-1);
157 p += strlen(p)+1;
158 strncpy(p, "", sizeof(clear_ticket)-PTR_DIFF(p,clear_ticket)-1);
159 p += strlen(p)+1;
160
161 /* And zero-pad to a multiple of 8 bytes */
162 len = PTR_DIFF(p, clear_ticket);
163 if (len & 7) {
164 uint32 extra_space = 8-(len & 7);
165 memset(p, 0, extra_space);
166 p+=extra_space;
167 }
168 len = PTR_DIFF(p, clear_ticket);
169
170 des_key_sched((const_des_cblock *)key.key, key_schedule);
171 des_pcbc_encrypt(clear_ticket, clear_ticket,
172 len, key_schedule, (C_Block *)key.key, 1);
173
174 ZERO_STRUCT(key);
175
176 *ticket = data_blob(clear_ticket, len);
177
178 return True;
179}
180
181char *afs_createtoken_str(const char *username, const char *cell)
182{
183 DATA_BLOB ticket;
184 struct ClearToken ct;
185 char *result;
186
187 if (!afs_createtoken(username, cell, &ticket, &ct))
188 return NULL;
189
190 result = afs_encode_token(cell, ticket, &ct);
191
192 data_blob_free(&ticket);
193
194 return result;
195}
196
197/*
198 This routine takes a radical approach completely bypassing the
199 Kerberos idea of security and using AFS simply as an intelligent
200 file backend. Samba has persuaded itself somehow that the user is
201 actually correctly identified and then we create a ticket that the
202 AFS server hopefully accepts using its KeyFile that the admin has
203 kindly stored to our secrets.tdb.
204
205 Thanks to the book "Network Security -- PRIVATE Communication in a
206 PUBLIC World" by Charlie Kaufman, Radia Perlman and Mike Speciner
207 Kerberos 4 tickets are not really hard to construct.
208
209 For the comments "Alice" is the User to be auth'ed, and "Bob" is the
210 AFS server. */
211
212BOOL afs_login(connection_struct *conn)
213{
214 extern userdom_struct current_user_info;
215 extern struct current_user current_user;
216 DATA_BLOB ticket;
217 pstring afs_username;
218 char *cell;
219 BOOL result;
220 char *ticket_str;
221 const DOM_SID *user_sid;
222
223 struct ClearToken ct;
224
225 pstrcpy(afs_username, lp_afs_username_map());
226 standard_sub_advanced(SNUM(conn), conn->user,
227 conn->connectpath, conn->gid,
228 get_current_username(),
229 current_user_info.domain,
230 afs_username, sizeof(afs_username));
231
232 user_sid = &current_user.nt_user_token->user_sids[0];
233 pstring_sub(afs_username, "%s", sid_string_static(user_sid));
234
235 /* The pts command always generates completely lower-case user
236 * names. */
237 strlower_m(afs_username);
238
239 cell = strchr(afs_username, '@');
240
241 if (cell == NULL) {
242 DEBUG(1, ("AFS username doesn't contain a @, "
243 "could not find cell\n"));
244 return False;
245 }
246
247 *cell = '\0';
248 cell += 1;
249
250 DEBUG(10, ("Trying to log into AFS for user %s@%s\n",
251 afs_username, cell));
252
253 if (!afs_createtoken(afs_username, cell, &ticket, &ct))
254 return False;
255
256 /* For which Unix-UID do we want to set the token? */
257 ct.ViceId = getuid();
258
259 ticket_str = afs_encode_token(cell, ticket, &ct);
260
261 result = afs_settoken_str(ticket_str);
262
263 SAFE_FREE(ticket_str);
264
265 data_blob_free(&ticket);
266
267 return result;
268}
269
270#else
271
272BOOL afs_login(connection_struct *conn)
273{
274 return True;
275}
276
277char *afs_createtoken_str(const char *username, const char *cell)
278{
279 return False;
280}
281
282#endif /* WITH_FAKE_KASERVER */
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