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
|
/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
#include <sys/param.h>
#include <stdint.h>
#include "tls/extensions/s2n_client_renegotiation_info.h"
#include "tls/s2n_tls.h"
#include "utils/s2n_safety.h"
static int s2n_client_renegotiation_send(struct s2n_connection *conn, struct s2n_stuffer *out);
static int s2n_client_renegotiation_recv(struct s2n_connection *conn, struct s2n_stuffer *extension);
static bool s2n_client_renegotiation_should_send(struct s2n_connection *conn);
const s2n_extension_type s2n_client_renegotiation_info_extension = {
.iana_value = TLS_EXTENSION_RENEGOTIATION_INFO,
.is_response = false,
.send = s2n_client_renegotiation_send,
.recv = s2n_client_renegotiation_recv,
.should_send = s2n_client_renegotiation_should_send,
/**
*= https://tools.ietf.org/rfc/rfc5746#3.6
*# o If neither the TLS_EMPTY_RENEGOTIATION_INFO_SCSV SCSV nor the
*# "renegotiation_info" extension was included, set the
*# secure_renegotiation flag to FALSE. In this case, some servers
*# may want to terminate the handshake instead of continuing
*
* The conn->secure_renegotiation flag defaults to false, so this is a no-op.
* We do not terminate the handshake, although missing messaging for secure
* renegotiation degrades client security.
*
* We could introduce an option to fail in this case in the future.
*/
.if_missing = s2n_extension_noop_if_missing,
};
/**
*= https://tools.ietf.org/rfc/rfc5746#3.5
*# o The client MUST include the "renegotiation_info" extension in the
*# ClientHello
*/
static bool s2n_client_renegotiation_should_send(struct s2n_connection *conn)
{
return conn && s2n_handshake_is_renegotiation(conn);
}
/**
*= https://tools.ietf.org/rfc/rfc5746#3.5
*# o The client MUST include the "renegotiation_info" extension in the
*# ClientHello, containing the saved client_verify_data.
*/
static int s2n_client_renegotiation_send(struct s2n_connection *conn, struct s2n_stuffer *out)
{
POSIX_ENSURE_REF(conn);
/**
*= https://tools.ietf.org/rfc/rfc5746#3.5
*# This text applies if the connection's "secure_renegotiation" flag is
*# set to TRUE (if it is set to FALSE, see Section 4.2).
*/
POSIX_ENSURE(conn->secure_renegotiation, S2N_ERR_NO_RENEGOTIATION);
uint8_t renegotiated_connection_len = conn->handshake.finished_len;
POSIX_GUARD(s2n_stuffer_write_uint8(out, renegotiated_connection_len));
POSIX_GUARD(s2n_stuffer_write_bytes(out, conn->handshake.client_finished, renegotiated_connection_len));
return S2N_SUCCESS;
}
/**
*= https://tools.ietf.org/rfc/rfc5746#3.6
*# o The server MUST check if the "renegotiation_info" extension is
*# included in the ClientHello.
*/
static int s2n_client_renegotiation_recv(struct s2n_connection *conn, struct s2n_stuffer *extension)
{
/**
*= https://tools.ietf.org/rfc/rfc5746#3.6
*# The server MUST then verify
*# that the length of the "renegotiated_connection" field is zero,
*# and if it is not, MUST abort the handshake.
*/
uint8_t renegotiated_connection_len = 0;
POSIX_GUARD(s2n_stuffer_read_uint8(extension, &renegotiated_connection_len));
POSIX_ENSURE(s2n_stuffer_data_available(extension) == 0, S2N_ERR_NON_EMPTY_RENEGOTIATION_INFO);
POSIX_ENSURE(renegotiated_connection_len == 0, S2N_ERR_NON_EMPTY_RENEGOTIATION_INFO);
/**
*= https://tools.ietf.org/rfc/rfc5746#3.6
*# If the extension is present, set secure_renegotiation flag to TRUE.
*/
conn->secure_renegotiation = 1;
return S2N_SUCCESS;
}
/* Old-style extension functions -- remove after extensions refactor is complete */
int s2n_recv_client_renegotiation_info(struct s2n_connection *conn, struct s2n_stuffer *extension)
{
return s2n_extension_recv(&s2n_client_renegotiation_info_extension, conn, extension);
}
|
