lbbs/src/test_ssh_server.c

#include "log.h"
#include <stdio.h>
#include <libssh/libssh.h>
#include <libssh/server.h>
#include <libssh/callbacks.h>

#ifndef BUF_SIZE
#define BUF_SIZE 2048
#endif

#define SSH_HOST_KEYFILE "../conf/ssh_host_rsa_key"

#define USER "test"
#define PASSWORD "123456"

static ssh_channel channel;
static int authenticated = 0;
static int tries = 0;
static int error = 0;

static int auth_password(ssh_session session, const char *user,
                                                 const char *password, void *userdata)
{
        (void)userdata;

        log_std("Authenticating user %s pwd %s\n", user, password);
        if (strcmp(user, USER) == 0 && strcmp(password, PASSWORD) == 0)
        {
                authenticated = 1;
                log_std("Authenticated\n");
                return SSH_AUTH_SUCCESS;
        }
        if (tries >= 3)
        {
                log_error("Too many authentication tries\n");
                ssh_disconnect(session);
                error = 1;
                return SSH_AUTH_DENIED;
        }
        tries++;
        return SSH_AUTH_DENIED;
}

static int pty_request(ssh_session session, ssh_channel channel, const char *term,
                                           int x, int y, int px, int py, void *userdata)
{
        (void)session;
        (void)channel;
        (void)term;
        (void)x;
        (void)y;
        (void)px;
        (void)py;
        (void)userdata;
        log_std("Allocated terminal\n");
        return 0;
}

static int shell_request(ssh_session session, ssh_channel channel, void *userdata)
{
        (void)session;
        (void)channel;
        (void)userdata;
        log_std("Allocated shell\n");
        return 0;
}
struct ssh_channel_callbacks_struct channel_cb = {
        .channel_pty_request_function = pty_request,
        .channel_shell_request_function = shell_request};

static ssh_channel new_session_channel(ssh_session session, void *userdata)
{
        (void)session;
        (void)userdata;

        if (channel != NULL)
                return NULL;

        log_std("Allocated session channel\n");
        channel = ssh_channel_new(session);
        ssh_callbacks_init(&channel_cb);
        ssh_set_channel_callbacks(channel, &channel_cb);

        return channel;
}

int ssh_server(const char *hostaddr, unsigned int port)
{
        ssh_session session;
        ssh_bind sshbind;
        ssh_event event;

        struct ssh_server_callbacks_struct cb = {
                .userdata = NULL,
                .auth_password_function = auth_password,
                .channel_open_request_session_function = new_session_channel};

        char buf[BUF_SIZE];
        char host[128] = "";
        int i, r;

        int ssh_log_level = SSH_LOG_WARNING;

        ssh_init();

        sshbind = ssh_bind_new();

        if (ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDADDR, hostaddr) < 0 ||
                ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDPORT, &port) < 0 ||
                ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY, SSH_HOST_KEYFILE) < 0 ||
                ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_LOG_VERBOSITY, &ssh_log_level) < 0)
        {
                log_error("Error setting SSH bind options: %s\n", ssh_get_error(sshbind));
                ssh_bind_free(sshbind);
                return -1;
        }

        if (ssh_bind_listen(sshbind) < 0)
        {
                log_error("Error listening at SSH server port: %s\n", ssh_get_error(sshbind));
                ssh_bind_free(sshbind);
                return -1;
        }

        while (1)
        {
                session = ssh_new();

                if (ssh_bind_accept(sshbind, session) == SSH_OK)
                {
                        pid_t pid = fork();
                        switch (pid)
                        {
                        case 0:
                                ssh_bind_free(sshbind);

                                ssh_callbacks_init(&cb);
                                ssh_set_server_callbacks(session, &cb);

                                if (ssh_handle_key_exchange(session))
                                {
                                        log_error("ssh_handle_key_exchange: %s\n", ssh_get_error(session));
                                        return 1;
                                }
                                ssh_set_auth_methods(session, SSH_AUTH_METHOD_PASSWORD | SSH_AUTH_METHOD_GSSAPI_MIC);

                                event = ssh_event_new();
                                ssh_event_add_session(event, session);

                                while (!(authenticated && channel != NULL))
                                {
                                        if (error)
                                                break;
                                        r = ssh_event_dopoll(event, -1);
                                        if (r == SSH_ERROR)
                                        {
                                                log_error("Error : %s\n", ssh_get_error(session));
                                                ssh_disconnect(session);
                                                _exit(1);
                                        }
                                }

                                if (error)
                                {
                                        log_error("Error, exiting loop\n");
                                        _exit(1);
                                }
                                else
                                {
                                        log_std("Authenticated and got a channel\n");
                                }

                                snprintf(buf, sizeof(buf), "Hello, welcome to the Sample SSH proxy.\r\nPlease select your destination: ");
                                ssh_channel_write(channel, buf, (uint32_t)strlen(buf));
                                do
                                {
                                        i = ssh_channel_read(channel, buf, sizeof(buf), 0);
                                        if (i > 0)
                                        {
                                                ssh_channel_write(channel, buf, (uint32_t)i);
                                                if (strlen(host) + (size_t)i < sizeof(host))
                                                {
                                                        strncat(host, buf, (size_t)i);
                                                }
                                                if (strchr(host, '\x0d'))
                                                {
                                                        *strchr(host, '\x0d') = '\0';
                                                        ssh_channel_write(channel, "\n", 1);
                                                        break;
                                                }
                                        }
                                        else
                                        {
                                                log_error("Error: %s\n", ssh_get_error(session));
                                                _exit(1);
                                        }
                                } while (i > 0);
                                snprintf(buf, sizeof(buf), "Trying to connect to \"%s\"\r\n", host);
                                ssh_channel_write(channel, buf, (uint32_t)strlen(buf));
                                log_std("%s", buf);

                                ssh_disconnect(session);
                                ssh_free(session);

                                _exit(0);
                        case -1:
                                log_error("Failed to fork\n");
                                break;
                        }
                }
                else
                {
                        log_error("%s\n", ssh_get_error(sshbind));
                }

                /* Since the session has been passed to a child fork, do some cleaning
                 * up at the parent process. */
                ssh_disconnect(session);
                ssh_free(session);
        }

        ssh_bind_free(sshbind);
        ssh_finalize();

        return 0;
}

int main(int argc, char *argv[])
{
        if (log_begin("../log/bbsd.log", "../log/error.log") < 0)
        {
                printf("Open log error\n");
                return -1;
        }

        log_std_redirect(STDOUT_FILENO);
        log_err_redirect(STDERR_FILENO);

        ssh_server("0.0.0.0", 2322);

        log_end();

        return 0;
}
1	#include "log.h"
2	#include <stdio.h>
3	#include <libssh/libssh.h>
4	#include <libssh/server.h>
5	#include <libssh/callbacks.h>
6
7	#ifndef BUF_SIZE
8	#define BUF_SIZE 2048
9	#endif
10
11	#define SSH_HOST_KEYFILE "../conf/ssh_host_rsa_key"
12
13	#define USER "test"
14	#define PASSWORD "123456"
15
16	static ssh_channel channel;
17	static int authenticated = 0;
18	static int tries = 0;
19	static int error = 0;
20
21	static int auth_password(ssh_session session, const char *user,
22	const char password, void userdata)
23	{
24	(void)userdata;
25
26	log_std("Authenticating user %s pwd %s\n", user, password);
27	if (strcmp(user, USER) == 0 && strcmp(password, PASSWORD) == 0)
28	{
29	authenticated = 1;
30	log_std("Authenticated\n");
31	return SSH_AUTH_SUCCESS;
32	}
33	if (tries >= 3)
34	{
35	log_error("Too many authentication tries\n");
36	ssh_disconnect(session);
37	error = 1;
38	return SSH_AUTH_DENIED;
39	}
40	tries++;
41	return SSH_AUTH_DENIED;
42	}
43
44	static int pty_request(ssh_session session, ssh_channel channel, const char *term,
45	int x, int y, int px, int py, void *userdata)
46	{
47	(void)session;
48	(void)channel;
49	(void)term;
50	(void)x;
51	(void)y;
52	(void)px;
53	(void)py;
54	(void)userdata;
55	log_std("Allocated terminal\n");
56	return 0;
57	}
58
59	static int shell_request(ssh_session session, ssh_channel channel, void *userdata)
60	{
61	(void)session;
62	(void)channel;
63	(void)userdata;
64	log_std("Allocated shell\n");
65	return 0;
66	}
67	struct ssh_channel_callbacks_struct channel_cb = {
68	.channel_pty_request_function = pty_request,
69	.channel_shell_request_function = shell_request};
70
71	static ssh_channel new_session_channel(ssh_session session, void *userdata)
72	{
73	(void)session;
74	(void)userdata;
75
76	if (channel != NULL)
77	return NULL;
78
79	log_std("Allocated session channel\n");
80	channel = ssh_channel_new(session);
81	ssh_callbacks_init(&channel_cb);
82	ssh_set_channel_callbacks(channel, &channel_cb);
83
84	return channel;
85	}
86
87	int ssh_server(const char *hostaddr, unsigned int port)
88	{
89	ssh_session session;
90	ssh_bind sshbind;
91	ssh_event event;
92
93	struct ssh_server_callbacks_struct cb = {
94	.userdata = NULL,
95	.auth_password_function = auth_password,
96	.channel_open_request_session_function = new_session_channel};
97
98	char buf[BUF_SIZE];
99	char host[128] = "";
100	int i, r;
101
102	int ssh_log_level = SSH_LOG_WARNING;
103
104	ssh_init();
105
106	sshbind = ssh_bind_new();
107
108	if (ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDADDR, hostaddr) < 0 \|\|
109	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDPORT, &port) < 0 \|\|
110	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY, SSH_HOST_KEYFILE) < 0 \|\|
111	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_LOG_VERBOSITY, &ssh_log_level) < 0)
112	{
113	log_error("Error setting SSH bind options: %s\n", ssh_get_error(sshbind));
114	ssh_bind_free(sshbind);
115	return -1;
116	}
117
118	if (ssh_bind_listen(sshbind) < 0)
119	{
120	log_error("Error listening at SSH server port: %s\n", ssh_get_error(sshbind));
121	ssh_bind_free(sshbind);
122	return -1;
123	}
124
125	while (1)
126	{
127	session = ssh_new();
128
129	if (ssh_bind_accept(sshbind, session) == SSH_OK)
130	{
131	pid_t pid = fork();
132	switch (pid)
133	{
134	case 0:
135	ssh_bind_free(sshbind);
136
137	ssh_callbacks_init(&cb);
138	ssh_set_server_callbacks(session, &cb);
139
140	if (ssh_handle_key_exchange(session))
141	{
142	log_error("ssh_handle_key_exchange: %s\n", ssh_get_error(session));
143	return 1;
144	}
145	ssh_set_auth_methods(session, SSH_AUTH_METHOD_PASSWORD \| SSH_AUTH_METHOD_GSSAPI_MIC);
146
147	event = ssh_event_new();
148	ssh_event_add_session(event, session);
149
150	while (!(authenticated && channel != NULL))
151	{
152	if (error)
153	break;
154	r = ssh_event_dopoll(event, -1);
155	if (r == SSH_ERROR)
156	{
157	log_error("Error : %s\n", ssh_get_error(session));
158	ssh_disconnect(session);
159	_exit(1);
160	}
161	}
162
163	if (error)
164	{
165	log_error("Error, exiting loop\n");
166	_exit(1);
167	}
168	else
169	{
170	log_std("Authenticated and got a channel\n");
171	}
172
173	snprintf(buf, sizeof(buf), "Hello, welcome to the Sample SSH proxy.\r\nPlease select your destination: ");
174	ssh_channel_write(channel, buf, (uint32_t)strlen(buf));
175	do
176	{
177	i = ssh_channel_read(channel, buf, sizeof(buf), 0);
178	if (i > 0)
179	{
180	ssh_channel_write(channel, buf, (uint32_t)i);
181	if (strlen(host) + (size_t)i < sizeof(host))
182	{
183	strncat(host, buf, (size_t)i);
184	}
185	if (strchr(host, '\x0d'))
186	{
187	*strchr(host, '\x0d') = '\0';
188	ssh_channel_write(channel, "\n", 1);
189	break;
190	}
191	}
192	else
193	{
194	log_error("Error: %s\n", ssh_get_error(session));
195	_exit(1);
196	}
197	} while (i > 0);
198	snprintf(buf, sizeof(buf), "Trying to connect to \"%s\"\r\n", host);
199	ssh_channel_write(channel, buf, (uint32_t)strlen(buf));
200	log_std("%s", buf);
201
202	ssh_disconnect(session);
203	ssh_free(session);
204
205	_exit(0);
206	case -1:
207	log_error("Failed to fork\n");
208	break;
209	}
210	}
211	else
212	{
213	log_error("%s\n", ssh_get_error(sshbind));
214	}
215
216	/* Since the session has been passed to a child fork, do some cleaning
217	* up at the parent process. */
218	ssh_disconnect(session);
219	ssh_free(session);
220	}
221
222	ssh_bind_free(sshbind);
223	ssh_finalize();
224
225	return 0;
226	}
227
228	int main(int argc, char *argv[])
229	{
230	if (log_begin("../log/bbsd.log", "../log/error.log") < 0)
231	{
232	printf("Open log error\n");
233	return -1;
234	}
235
236	log_std_redirect(STDOUT_FILENO);
237	log_err_redirect(STDERR_FILENO);
238
239	ssh_server("0.0.0.0", 2322);
240
241	log_end();
242
243	return 0;
244	}
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