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
|
#include <fcntl.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "tcp.h"
#include "tls.h"
int sd = 0;
gnutls_session_t session;
gnutls_certificate_credentials_t xcred;
void tls_init(void)
{
gnutls_global_init();
gnutls_certificate_allocate_credentials(&xcred);
//gnutls_certificate_set_x509_trust_file(xcred, cafile, GNUTLS_X509_FMT_PEM);
//gnutls_certificate_set_verify_function(xcred, _verify_certificate_callback);
//gnutls_certificate_set_x509_key_file (xcred, "cert.pem", "key.pem", GNUTLS_X509_FMT_PEM);
gnutls_init(&session, GNUTLS_CLIENT);
// Only usefull if accessing a virtual hosting server
//gnutls_session_set_ptr(session, (void *) "my_host_name");
//gnutls_server_name_set(session, GNUTLS_NAME_DNS, "my_host_name", strlen("my_host_name"));
gnutls_set_default_priority(session);
gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, xcred);
}
int tls_connect(const char* const host, const unsigned short port)
{
int ret;
sd = tcp_connect(host, port);
if (sd < 0) {
tls_clean();
exit(101);
}
gnutls_transport_set_int(session, sd);
gnutls_handshake_set_timeout(session, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);
/* Perform the TLS handshake */
do {
ret = gnutls_handshake(session);
}
while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
if (ret < 0) {
fprintf(stderr, "TLS Handshake failed\n");
gnutls_perror(ret);
tls_clean();
exit(102);
} else {
char *desc;
desc = gnutls_session_get_desc(session);
printf("# TLS Session info: %s\n", desc);
gnutls_free(desc);
}
int sf = fcntl (sd, F_GETFL, 0);
if (sf == -1) {
perror("fcntl get");
return -1;
}
fcntl(sd, F_SETFL, sf | O_NONBLOCK);
if (sf == -1) {
perror("fcntl set");
return -1;
}
return sd;
}
int tls_read(int (*input_handler_callback)(const char* const sbuf, const int len))
{
char sbuf[512]; /* string buffer */
int len = 0; /* len read from the server */
len = gnutls_record_recv(session, sbuf, sizeof(sbuf));
if (len == 0) {
printf("Server has closed the TLS connection\n");
tls_clean();
return 1;
} else if (len < 0 && gnutls_error_is_fatal(len) == 0) {
fprintf(stderr, "*** Warning: %s\n", gnutls_strerror(len));
return 3;
} else if (len < 0) {
fprintf(stderr, "*** Error: %s\n", gnutls_strerror(len));
tls_clean();
return 2;
} else {
if (input_handler_callback(sbuf, len) != 0) {
return 0;
}
}
return 4;
}
void tls_send(char *buf, int len)
{
gnutls_record_send(session, buf, len);
}
void tls_close(void) {
gnutls_bye(session, GNUTLS_SHUT_RDWR);
tls_clean();
}
void tls_clean(void)
{
tcp_close(sd);
gnutls_deinit(session);
gnutls_certificate_free_credentials(xcred);
gnutls_global_deinit();
}
/* This function will verify the peer's certificate, and check
* if the hostname matches, as well as the activation, expiration dates. */
//static int _verify_certificate_callback(gnutls_session_t session)
//{
// unsigned int status;
// int ret, type;
// const char *hostname;
// gnutls_datum_t out;
//
// /* read hostname */
// hostname = gnutls_session_get_ptr(session);
//
// /* This verification function uses the trusted CAs in the credentials
// * structure. So you must have installed one or more CA certificates. */
// gnutls_typed_vdata_st data[2];
//
// memset(data, 0, sizeof(data));
//
// data[0].type = GNUTLS_DT_DNS_HOSTNAME;
// data[0].data = (void*)hostname;
//
// data[1].type = GNUTLS_DT_KEY_PURPOSE_OID;
// data[1].data = (void*)GNUTLS_KP_TLS_WWW_SERVER;
//
// ret = gnutls_certificate_verify_peers(session, data, 2, &status);
// if (ret < 0) {
// printf("Error\n");
// return GNUTLS_E_CERTIFICATE_ERROR;
// }
//
// type = gnutls_certificate_type_get(session);
//
// ret = gnutls_certificate_verification_status_print(status, type, &out, 0);
// if (ret < 0) {
// printf("Error\n");
// return GNUTLS_E_CERTIFICATE_ERROR;
// }
//
// printf("%s", out.data);
//
// gnutls_free(out.data);
//
// if (status != 0) /* Certificate is not trusted */
// return GNUTLS_E_CERTIFICATE_ERROR;
//
// /* notify gnutls to continue handshake normally */
// return 0;
//}
|
