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
|
/*
* Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Hyra nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <net/stpsession.h>
#include <net/param.h>
#include <crypto/ecdh.h>
#include <arpa/inet.h>
#include <defs.h>
#include <stdio.h>
#include <stdint.h>
#include <unistd.h>
#include <string.h>
#define CENTRAL_SERVER "149.248.6.149"
#define OSTP_PORT 5352
static const char *pap_codestr[] = {
[PAP_SUCCESS] = "success",
[PAP_BAD_SPW] = "bad SPW",
[PAP_BAD_PERMS] = "insufficient permissions",
[PAP_RESOURCE] = "server out of resources"
};
static void
log_pubkey(uint8_t pubkey[])
{
for (size_t i = 0; i < 32; ++i) {
printf("%02X ", pubkey[i] & 0xFF);
if (i != 0 && i % 4 == 0) {
printf("\n");
}
}
printf("\n");
}
static int
negotiate_spw(int sockfd, const unsigned char *session_key)
{
struct aes_message am;
struct msg_frame msg_frame;
struct pap pap;
unsigned char *tmp;
int error;
/* Create a PAP and encrypt it */
pap.spw = 0x8000;
pap.code = 0;
while (1) {
if ((error = send_frame(sockfd, &pap, sizeof(pap), session_key)) < 0) {
return error;
}
/* Receive the PAP the server replies with */
if ((error = recv_frame(sockfd, sizeof(pap), session_key, &pap)) < 0) {
return error;
}
/*
* If the server echos our PAP with code 0 then it has
* applied our session parameters! However, there is
* a chance arbitration will be needed and we need
* to look out for that too...
*/
if (pap.code == 0) {
printf("** Negotiation success\n");
break;
}
printf("** Arbitration needed, server says: %s\n", pap_codestr[pap.code]);
printf("** Server proposes SPW of 0x%0X, accepting\n", pap.spw);
pap.spw |= PAP_SPW_QSR;
pap.code = 0;
}
return 0;
}
static void
recv_motd(int sockfd, const unsigned char *session_key)
{
char buf[4096];
int len;
/* Receive the PAP the server replies with */
if ((len = recv_frame(sockfd, sizeof(buf), session_key, buf)) < 0) {
printf("Failed to recv MOTD...\n");
return;
}
buf[len] = '\0';
printf("%s\n", buf);
}
static int
request_session(void)
{
struct sockaddr_in addr;
struct session_request stp_sq;
struct x25519_keypair keypair;
unsigned char serv_pubkey[32];
unsigned char *session_key;
int error, sockfd;
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = inet_addr(CENTRAL_SERVER);
addr.sin_port = htons(OSTP_PORT);
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0) {
return sockfd;
}
error = connect(sockfd, (struct sockaddr *)&addr, sizeof(addr));
if (error < 0) {
printf("Failed to connect!\n");
close(sockfd);
return error;
}
printf("Generating keys...\n");
/* Generate an ephemeral keypair */
if ((error = gen_x25519_keypair(&keypair)) < 0) {
printf("Key generation failed!\n");
close(sockfd);
return error;
}
/*
* Setup the session request and add our public
* key to it.
*
* TODO: Use the 'U' bit in options.
*/
memset(stp_sq.hash, 0, sizeof(stp_sq.hash));
stp_sq.options = 0;
memcpy(stp_sq.pubkey, keypair.pubkey, sizeof(stp_sq.pubkey));
log_pubkey(keypair.pubkey);
printf("Sending session request...\n");
error = send(sockfd, &stp_sq, sizeof(stp_sq), 0);
if (error < 0) {
perror("Failed to send session request");
close(sockfd);
return error;
}
error = recv(sockfd, serv_pubkey, sizeof(serv_pubkey), 0);
if (error < 0) {
perror("Failed to get public key from peer\n");
close(sockfd);
return error;
}
if (error == 0) {
printf("Connection closed by peer\n");
close(sockfd);
return 0;
}
printf("Got public key from server\n");
log_pubkey(serv_pubkey);
printf("Deriving session key...\n");
gen_session_key(keypair.privkey, serv_pubkey, &session_key);
/* Send server SPW bits */
if ((error = negotiate_spw(sockfd, session_key)) < 0) {
printf("Session Parameter Negotiation failed\n");
free_session_key(session_key);
close(sockfd);
return error;
}
recv_motd(sockfd, session_key);
free_session_key(session_key);
close(sockfd);
return 0;
}
int
main(void)
{
return request_session();
}
|
