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
|
/*
* Copyright (C) 2001 Nikos Mavroyanopoulos
*
* This file is part of GNUTLS.
*
* The GNUTLS library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/* Functions that relate to the TLS hello extension parsing.
* Hello extensions are packets appended in the TLS hello packet, and
* allow for extra functionality.
*/
#include "gnutls_int.h"
#include "gnutls_extensions.h"
#include "gnutls_errors.h"
#include "ext_max_record.h"
#include <ext_cert_type.h>
#include "gnutls_num.h"
/* Key Exchange Section */
#define GNUTLS_EXTENSION_ENTRY(type, ext_func_recv, ext_func_send) \
{ #type, type, ext_func_recv, ext_func_send }
#define MAX_EXT_SIZE 10
const int _gnutls_extensions_size = MAX_EXT_SIZE;
gnutls_extension_entry _gnutls_extensions[MAX_EXT_SIZE] = {
GNUTLS_EXTENSION_ENTRY( GNUTLS_EXTENSION_MAX_RECORD_SIZE, _gnutls_max_record_recv_params, _gnutls_max_record_send_params),
GNUTLS_EXTENSION_ENTRY( GNUTLS_EXTENSION_CERT_TYPE, _gnutls_cert_type_recv_params, _gnutls_cert_type_send_params),
{0}
};
#define GNUTLS_EXTENSION_LOOP2(b) \
gnutls_extension_entry *p; \
for(p = _gnutls_extensions; p->name != NULL; p++) { b ; }
#define GNUTLS_EXTENSION_LOOP(a) \
GNUTLS_EXTENSION_LOOP2( if(p->type == type) { a; break; } )
/* EXTENSION functions */
void* _gnutls_ext_func_recv(uint16 type)
{
void* ret=NULL;
GNUTLS_EXTENSION_LOOP(ret = p->gnutls_ext_func_recv);
return ret;
}
void* _gnutls_ext_func_send(uint16 type)
{
void* ret=NULL;
GNUTLS_EXTENSION_LOOP(ret = p->gnutls_ext_func_send);
return ret;
}
const char *_gnutls_extension_get_name(uint16 type)
{
const char *ret = NULL;
/* avoid prefix */
GNUTLS_EXTENSION_LOOP(ret = p->name + sizeof("EXTENSION_") - 1);
return ret;
}
/* Checks if the extension we just received is one of the
* requested ones. Otherwise it's a fatal error.
*/
static int _gnutls_extension_list_check( gnutls_session session, uint16 type) {
int i;
if (session->security_parameters.entity==GNUTLS_CLIENT) {
for(i=0;i<session->internals.extensions_sent_size;i++) {
if (type==session->internals.extensions_sent[i])
return 0; /* ok found */
}
return GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION;
}
return 0;
}
int _gnutls_parse_extensions( gnutls_session session, const opaque* data, int data_size) {
int next, ret;
int pos=0;
uint16 type;
const opaque* sdata;
int (*ext_func_recv)( gnutls_session, const opaque*, int);
uint16 size;
#ifdef DEBUG
int i;
if (session->security_parameters.entity==GNUTLS_CLIENT)
for (i=0;i<session->internals.extensions_sent_size;i++) {
_gnutls_log("EXT: expecting extension %d\n", session->internals.extensions_sent[i]);
}
#endif
DECR_LENGTH_RET( data_size, 2, 0);
next = _gnutls_read_uint16( data);
pos+=2;
DECR_LENGTH_RET( data_size, next, 0);
do {
DECR_LENGTH_RET( next, 1, 0);
type = _gnutls_read_uint16( &data[pos]);
pos+=2;
if ( (ret=_gnutls_extension_list_check( session, type)) < 0) {
gnutls_assert();
return ret;
}
DECR_LENGTH_RET( next, 2, 0);
size = _gnutls_read_uint16(&data[pos]);
pos+=2;
DECR_LENGTH_RET( next, size, 0);
sdata = &data[pos];
pos+=size;
ext_func_recv = _gnutls_ext_func_recv(type);
if (ext_func_recv == NULL) continue;
if ( (ret=ext_func_recv( session, sdata, size)) < 0) {
gnutls_assert();
return ret;
}
} while(next > 2);
return 0;
}
/* Adds the extension we want to send in the extensions list.
* This list is used to check whether the (later) received
* extensions are the ones we requested.
*/
static void _gnutls_extension_list_add( gnutls_session session, uint16 type) {
if (session->security_parameters.entity==GNUTLS_CLIENT) {
if (session->internals.extensions_sent_size < MAX_EXT_TYPES) {
session->internals.extensions_sent[session->internals.extensions_sent_size] = type;
session->internals.extensions_sent_size++;
} else {
#ifdef DEBUG
_gnutls_log("EXT: Increase MAX_EXT_TYPES\n");
#endif
}
}
return;
}
int _gnutls_gen_extensions( gnutls_session session, opaque** data) {
int next, size;
uint16 pos=0;
opaque sdata[1024];
int sdata_size = sizeof(sdata);
int (*ext_func_send)( gnutls_session, opaque*, int);
(*data) = gnutls_malloc(2); /* allocate size for size */
pos+=2;
if ((*data)==NULL) {
gnutls_assert();
return GNUTLS_E_MEMORY_ERROR;
}
next = MAX_EXT_TYPES; /* maximum supported extensions */
do {
next--;
ext_func_send = _gnutls_ext_func_send(next);
if (ext_func_send == NULL) continue;
size = ext_func_send( session, sdata, sdata_size);
if (size > 0) {
(*data) = gnutls_realloc( (*data), pos+size+4);
if ((*data)==NULL) {
gnutls_assert();
return GNUTLS_E_MEMORY_ERROR;
}
/* write extension type */
_gnutls_write_uint16( next, &(*data)[pos]);
pos+=2;
/* write size */
_gnutls_write_uint16( size, &(*data)[pos]);
pos+=2;
memcpy( &(*data)[pos], sdata, size);
pos+=size;
/* add this extension to the extension list
*/
_gnutls_extension_list_add( session, next);
}
} while(next >= 0);
size = pos;
pos-=2; /* remove the size of the size header! */
_gnutls_write_uint16( pos, (*data));
if (size==2) { /* empty */
size = 0;
gnutls_free(*data);
(*data) = NULL;
}
return size;
}
|
