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
|
/*
* Copyright (C) 2001, 2004, 2005 Free Software Foundation
*
* Author: 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA
*
*/
/* This file contains the code for the Max Record Size TLS extension.
*/
#include "gnutls_int.h"
#include "gnutls_errors.h"
#include "gnutls_num.h"
#include <ext_max_record.h>
/*
* In case of a server: if a MAX_RECORD_SIZE extension type is received then it stores
* into the session the new value. The server may use gnutls_get_max_record_size(),
* in order to access it.
*
* In case of a client: If a different max record size (than the default) has
* been specified then it sends the extension.
*
*/
int
_gnutls_max_record_recv_params (gnutls_session_t session,
const opaque * data, size_t _data_size)
{
ssize_t new_size;
ssize_t data_size = _data_size;
if (session->security_parameters.entity == GNUTLS_SERVER)
{
if (data_size > 0)
{
DECR_LEN (data_size, 1);
new_size = _gnutls_mre_num2record (data[0]);
if (new_size < 0)
{
gnutls_assert ();
return new_size;
}
session->security_parameters.max_record_send_size = new_size;
session->security_parameters.max_record_recv_size = new_size;
}
}
else
{ /* CLIENT SIDE - we must check if the sent record size is the right one
*/
if (data_size > 0)
{
if (data_size != 1)
{
gnutls_assert ();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
new_size = _gnutls_mre_num2record (data[0]);
if (new_size < 0
|| new_size != session->internals.proposed_record_size)
{
gnutls_assert ();
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
else
{
session->security_parameters.max_record_recv_size =
session->internals.proposed_record_size;
}
}
}
return 0;
}
/* returns data_size or a negative number on failure
*/
int
_gnutls_max_record_send_params (gnutls_session_t session, opaque * data,
size_t data_size)
{
uint16_t len;
/* this function sends the client extension data (dnsname) */
if (session->security_parameters.entity == GNUTLS_CLIENT)
{
if (session->internals.proposed_record_size != DEFAULT_MAX_RECORD_SIZE)
{
len = 1;
if (data_size < len)
{
gnutls_assert ();
return GNUTLS_E_SHORT_MEMORY_BUFFER;
}
data[0] =
(uint8_t) _gnutls_mre_record2num (session->internals.
proposed_record_size);
return len;
}
}
else
{ /* server side */
if (session->security_parameters.max_record_recv_size !=
DEFAULT_MAX_RECORD_SIZE)
{
len = 1;
if (data_size < len)
{
gnutls_assert ();
return GNUTLS_E_SHORT_MEMORY_BUFFER;
}
data[0] =
(uint8_t) _gnutls_mre_record2num (session->
security_parameters.
max_record_recv_size);
return len;
}
}
return 0;
}
/* Maps numbers to record sizes according to the
* extensions draft.
*/
int
_gnutls_mre_num2record (int num)
{
switch (num)
{
case 1:
return 512;
case 2:
return 1024;
case 3:
return 2048;
case 4:
return 4096;
default:
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
}
/* Maps record size to numbers according to the
* extensions draft.
*/
int
_gnutls_mre_record2num (uint16_t record_size)
{
switch (record_size)
{
case 512:
return 1;
case 1024:
return 2;
case 2048:
return 3;
case 4096:
return 4;
default:
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
}
|
