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
|
/*
* 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.
*/
/* Target Functions: s2n_client_hello_recv s2n_parse_client_hello s2n_populate_client_hello_extensions
s2n_process_client_hello s2n_collect_client_hello */
#include <stdint.h>
#include <openssl/crypto.h>
#include <openssl/err.h>
#include "api/s2n.h"
#include "stuffer/s2n_stuffer.h"
#include "tls/s2n_connection.h"
#include "tls/s2n_tls.h"
#include "utils/s2n_safety.h"
#include "s2n_test.h"
#include "tls/s2n_tls13.h"
static const uint8_t TLS_VERSIONS[] = {S2N_TLS10, S2N_TLS11, S2N_TLS12, S2N_TLS13};
int s2n_fuzz_init(int *argc, char **argv[])
{
POSIX_GUARD(s2n_enable_tls13_in_test());
srand(time(0));
return S2N_SUCCESS;
}
/* Returns the value of ctx as an int when called */
int client_hello_cb_ret(struct s2n_connection *conn, void *ctx)
{
return *((int*)ctx);
}
int s2n_fuzz_test(const uint8_t *buf, size_t len)
{
/* We need at least two bytes of input to set parameters */
S2N_FUZZ_ENSURE_MIN_LEN(len, 2);
/* Setup */
struct s2n_connection *server_conn = s2n_connection_new(S2N_SERVER);
POSIX_ENSURE_REF(server_conn);
POSIX_GUARD(s2n_stuffer_write_bytes(&server_conn->handshake.io, buf, len));
/* Pull a byte off the libfuzzer input and use it to set parameters */
uint8_t randval = 0;
int ctxval = 0;
POSIX_GUARD(s2n_stuffer_read_uint8(&server_conn->handshake.io, &randval));
server_conn->actual_protocol_version = TLS_VERSIONS[(randval & 0x0F) % s2n_array_len(TLS_VERSIONS)];
server_conn->server_protocol_version = TLS_VERSIONS[(randval >> 4) % s2n_array_len(TLS_VERSIONS)];
/* When callback function is called, return int chosen by libfuzzer between -1 and 1 to reach all code branches */
POSIX_GUARD(s2n_stuffer_read_uint8(&server_conn->handshake.io, &randval));
ctxval = (int)(randval % 3) - 1;
POSIX_GUARD(s2n_config_set_client_hello_cb(server_conn->config, client_hello_cb_ret, &ctxval));
/* Run Test
* Do not use GUARD macro here since the connection memory hasn't been freed.
*/
s2n_client_hello_recv(server_conn);
/* Cleanup */
POSIX_GUARD(s2n_connection_free(server_conn));
return S2N_SUCCESS;
}
S2N_FUZZ_TARGET(s2n_fuzz_init, s2n_fuzz_test, NULL)
|
