1 /*
2 * Sample showing how to do SSH2 connect using ssh-agent.
3 *
4 * The sample code has default values for host name, user name:
5 *
6 * "ssh2_agent host user"
7 */
8
9 #include "libssh2_config.h"
10 #include <libssh2.h>
11 #include <libssh2_sftp.h>
12
13 #ifdef HAVE_WINDOWS_H
14 # include <windows.h>
15 #endif
16 #ifdef HAVE_WINSOCK2_H
17 # include <winsock2.h>
18 #endif
19 #ifdef HAVE_SYS_SOCKET_H
20 # include <sys/socket.h>
21 #endif
22 #ifdef HAVE_NETINET_IN_H
23 # include <netinet/in.h>
24 #endif
25 # ifdef HAVE_UNISTD_H
26 #include <unistd.h>
27 #endif
28 # ifdef HAVE_ARPA_INET_H
29 #include <arpa/inet.h>
30 #endif
31
32 #include <sys/types.h>
33 #include <fcntl.h>
34 #include <errno.h>
35 #include <stdio.h>
36 #include <ctype.h>
37 #include <stdlib.h>
38
39 const char *username = "username";
40
main(int argc,char * argv[])41 int main(int argc, char *argv[])
42 {
43 unsigned long hostaddr;
44 int sock = -1, i, rc;
45 struct sockaddr_in sin;
46 const char *fingerprint;
47 char *userauthlist;
48 LIBSSH2_SESSION *session = NULL;
49 LIBSSH2_CHANNEL *channel;
50 LIBSSH2_AGENT *agent = NULL;
51 struct libssh2_agent_publickey *identity, *prev_identity = NULL;
52
53 #ifdef WIN32
54 WSADATA wsadata;
55 int err;
56
57 err = WSAStartup(MAKEWORD(2, 0), &wsadata);
58 if(err != 0) {
59 fprintf(stderr, "WSAStartup failed with error: %d\n", err);
60 return 1;
61 }
62 #endif
63
64 if(argc > 1) {
65 hostaddr = inet_addr(argv[1]);
66 }
67 else {
68 hostaddr = htonl(0x7F000001);
69 }
70
71 if(argc > 2) {
72 username = argv[2];
73 }
74
75 rc = libssh2_init(0);
76 if(rc != 0) {
77 fprintf(stderr, "libssh2 initialization failed (%d)\n", rc);
78 return 1;
79 }
80
81 /* Ultra basic "connect to port 22 on localhost". Your code is
82 * responsible for creating the socket establishing the connection
83 */
84 sock = socket(AF_INET, SOCK_STREAM, 0);
85 if(sock == -1) {
86 fprintf(stderr, "failed to create socket!\n");
87 rc = 1;
88 goto shutdown;
89 }
90
91 sin.sin_family = AF_INET;
92 sin.sin_port = htons(22);
93 sin.sin_addr.s_addr = hostaddr;
94 if(connect(sock, (struct sockaddr*)(&sin),
95 sizeof(struct sockaddr_in)) != 0) {
96 fprintf(stderr, "failed to connect!\n");
97 goto shutdown;
98 }
99
100 /* Create a session instance and start it up. This will trade welcome
101 * banners, exchange keys, and setup crypto, compression, and MAC layers
102 */
103 session = libssh2_session_init();
104 if(libssh2_session_handshake(session, sock)) {
105 fprintf(stderr, "Failure establishing SSH session\n");
106 return 1;
107 }
108
109 /* At this point we havn't authenticated. The first thing to do is check
110 * the hostkey's fingerprint against our known hosts Your app may have it
111 * hard coded, may go to a file, may present it to the user, that's your
112 * call
113 */
114 fingerprint = libssh2_hostkey_hash(session, LIBSSH2_HOSTKEY_HASH_SHA1);
115 fprintf(stderr, "Fingerprint: ");
116 for(i = 0; i < 20; i++) {
117 fprintf(stderr, "%02X ", (unsigned char)fingerprint[i]);
118 }
119 fprintf(stderr, "\n");
120
121 /* check what authentication methods are available */
122 userauthlist = libssh2_userauth_list(session, username, strlen(username));
123 fprintf(stderr, "Authentication methods: %s\n", userauthlist);
124 if(strstr(userauthlist, "publickey") == NULL) {
125 fprintf(stderr, "\"publickey\" authentication is not supported\n");
126 goto shutdown;
127 }
128
129 /* Connect to the ssh-agent */
130 agent = libssh2_agent_init(session);
131 if(!agent) {
132 fprintf(stderr, "Failure initializing ssh-agent support\n");
133 rc = 1;
134 goto shutdown;
135 }
136 if(libssh2_agent_connect(agent)) {
137 fprintf(stderr, "Failure connecting to ssh-agent\n");
138 rc = 1;
139 goto shutdown;
140 }
141 if(libssh2_agent_list_identities(agent)) {
142 fprintf(stderr, "Failure requesting identities to ssh-agent\n");
143 rc = 1;
144 goto shutdown;
145 }
146 while(1) {
147 rc = libssh2_agent_get_identity(agent, &identity, prev_identity);
148 if(rc == 1)
149 break;
150 if(rc < 0) {
151 fprintf(stderr,
152 "Failure obtaining identity from ssh-agent support\n");
153 rc = 1;
154 goto shutdown;
155 }
156 if(libssh2_agent_userauth(agent, username, identity)) {
157 fprintf(stderr, "\tAuthentication with username %s and "
158 "public key %s failed!\n",
159 username, identity->comment);
160 }
161 else {
162 fprintf(stderr, "\tAuthentication with username %s and "
163 "public key %s succeeded!\n",
164 username, identity->comment);
165 break;
166 }
167 prev_identity = identity;
168 }
169 if(rc) {
170 fprintf(stderr, "Couldn't continue authentication\n");
171 goto shutdown;
172 }
173
174 /* We're authenticated now. */
175
176 /* Request a shell */
177 channel = libssh2_channel_open_session(session);
178 if(!channel) {
179 fprintf(stderr, "Unable to open a session\n");
180 goto shutdown;
181 }
182
183 /* Some environment variables may be set,
184 * It's up to the server which ones it'll allow though
185 */
186 libssh2_channel_setenv(channel, "FOO", "bar");
187
188 /* Request a terminal with 'vanilla' terminal emulation
189 * See /etc/termcap for more options
190 */
191 if(libssh2_channel_request_pty(channel, "vanilla")) {
192 fprintf(stderr, "Failed requesting pty\n");
193 goto skip_shell;
194 }
195
196 /* Open a SHELL on that pty */
197 if(libssh2_channel_shell(channel)) {
198 fprintf(stderr, "Unable to request shell on allocated pty\n");
199 goto shutdown;
200 }
201
202 /* At this point the shell can be interacted with using
203 * libssh2_channel_read()
204 * libssh2_channel_read_stderr()
205 * libssh2_channel_write()
206 * libssh2_channel_write_stderr()
207 *
208 * Blocking mode may be (en|dis)abled with: libssh2_channel_set_blocking()
209 * If the server send EOF, libssh2_channel_eof() will return non-0
210 * To send EOF to the server use: libssh2_channel_send_eof()
211 * A channel can be closed with: libssh2_channel_close()
212 * A channel can be freed with: libssh2_channel_free()
213 */
214
215 skip_shell:
216 if(channel) {
217 libssh2_channel_free(channel);
218 channel = NULL;
219 }
220
221 /* Other channel types are supported via:
222 * libssh2_scp_send()
223 * libssh2_scp_recv2()
224 * libssh2_channel_direct_tcpip()
225 */
226
227 shutdown:
228
229 if(agent) {
230 libssh2_agent_disconnect(agent);
231 libssh2_agent_free(agent);
232 }
233
234 if(session) {
235 libssh2_session_disconnect(session,
236 "Normal Shutdown, Thank you for playing");
237 libssh2_session_free(session);
238 }
239
240 if(sock != -1) {
241 #ifdef WIN32
242 closesocket(sock);
243 #else
244 close(sock);
245 #endif
246 }
247
248 fprintf(stderr, "all done!\n");
249
250 libssh2_exit();
251
252 return rc;
253 }
254