lbbs/src/test_ssh_server.c

/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
 * test_ssh_server
 *   - tester for network server with SSH support
 *
 * Copyright (C) 2004-2026  Leaflet <leaflet@leafok.com>
 */

// This test was written based on libssh example/proxy.c

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

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

enum test_ssh_server_constant_t
{
        BUF_SIZE = 2048,
};

static const char SSH_HOST_RSA_KEY_FILE[] = "../conf/ssh_host_rsa_key";
static const char SSH_HOST_ED25519_KEY_FILE[] = "../conf/ssh_host_ed25519_key";
static const char SSH_HOST_ECDSA_KEY_FILE[] = "../conf/ssh_host_ecdsa_key";

static const char USER[] = "test";
static const char PASSWORD[] = "123456";

static ssh_channel SSH_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_common("Authenticating user %s pwd %s", user, password);
        if (strcmp(user, USER) == 0 && strcmp(password, PASSWORD) == 0)
        {
                authenticated = 1;
                log_common("Authenticated");
                return SSH_AUTH_SUCCESS;
        }
        if (tries >= 3)
        {
                log_error("Too many authentication tries");
                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_common("Allocated terminal");
        return 0;
}

static int shell_request(ssh_session session, ssh_channel channel, void *userdata)
{
        (void)session;
        (void)channel;
        (void)userdata;
        log_common("Allocated shell");
        return 0;
}

struct ssh_channel_callbacks_struct channel_cb = {
        .channel_pty_request_function = pty_request,
        .channel_shell_request_function = shell_request};

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

        if (SSH_channel != NULL)
                return NULL;

        log_common("Allocated session channel");
        SSH_channel = ssh_channel_new(session);
        ssh_callbacks_init(&channel_cb);
        ssh_set_channel_callbacks(SSH_channel, &channel_cb);

        return SSH_channel;
}

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

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

        long int ssh_timeout = 0;

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

        int ssh_key_valid = 0;
        int ssh_log_level = SSH_LOG_PROTOCOL;

        ssh_init();

        sshbind = ssh_bind_new();

        if (ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY, SSH_HOST_RSA_KEY_FILE) < 0)
        {
                log_error("Error loading SSH RSA key: %s", SSH_HOST_RSA_KEY_FILE);
        }
        else
        {
                ssh_key_valid = 1;
        }
        if (ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY, SSH_HOST_ED25519_KEY_FILE) < 0)
        {
                log_error("Error loading SSH ED25519 key: %s", SSH_HOST_ED25519_KEY_FILE);
        }
        else
        {
                ssh_key_valid = 1;
        }
        if (ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY, SSH_HOST_ECDSA_KEY_FILE) < 0)
        {
                log_error("Error loading SSH ECDSA key: %s", SSH_HOST_ECDSA_KEY_FILE);
        }
        else
        {
                ssh_key_valid = 1;
        }

        if (!ssh_key_valid)
        {
                log_error("Error: no valid SSH host key");
                ssh_bind_free(sshbind);
                return -1;
        }

        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_ALGORITHMS, "+ssh-ed25519,ecdsa-sha2-nistp256,ssh-rsa") < 0 ||
                ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_LOG_VERBOSITY, &ssh_log_level) < 0)
        {
                log_error("Error setting SSH bind options: %s", 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", 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);

                                ssh_timeout = 60; // second
                                if (ssh_options_set(session, SSH_OPTIONS_TIMEOUT, &ssh_timeout) < 0)
                                {
                                        log_error("Error setting SSH options: %s", ssh_get_error(session));
                                        ssh_disconnect(session);
                                        _exit(1);
                                }

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

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

                                ssh_timeout = 0;
                                if (ssh_options_set(session, SSH_OPTIONS_TIMEOUT, &ssh_timeout) < 0)
                                {
                                        log_error("Error setting SSH options: %s", ssh_get_error(session));
                                        ssh_disconnect(session);
                                        _exit(1);
                                }

                                snprintf(buf, sizeof(buf), "Hello, welcome to the Sample SSH proxy.\nPlease select your destination: ");
                                ssh_channel_write(SSH_channel, buf, (uint32_t)strlen(buf));
                                do
                                {
                                        i = ssh_channel_read(SSH_channel, buf, sizeof(buf), 0);
                                        if (i > 0)
                                        {
                                                ssh_channel_write(SSH_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(SSH_channel, "\n", 1);
                                                        break;
                                                }
                                        }
                                        else
                                        {
                                                log_error("Error: %s", ssh_get_error(session));
                                                _exit(1);
                                        }
                                } while (i > 0);
                                snprintf(buf, sizeof(buf), "Trying to connect to \"%s\"\n", host);
                                ssh_channel_write(SSH_channel, buf, (uint32_t)strlen(buf));
                                log_common("%s", buf);

                                ssh_disconnect(session);
                                ssh_free(session);

                                _exit(0);
                        case -1:
                                log_error("Failed to fork");
                                break;
                        }
                }
                else
                {
                        log_error("%s", 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_common_redir(STDOUT_FILENO);
        log_error_redir(STDERR_FILENO);

        ssh_server("0.0.0.0", 2322);

        log_end();

        return 0;
}
1	/* SPDX-License-Identifier: GPL-3.0-or-later */
2	/*
3	* test_ssh_server
4	* - tester for network server with SSH support
5	*
6	* Copyright (C) 2004-2026 Leaflet <leaflet@leafok.com>
7	*/
8
9	// This test was written based on libssh example/proxy.c
10
11	#ifdef HAVE_CONFIG_H
12	#include "config.h"
13	#endif
14
15	#include "log.h"
16	#include <stdio.h>
17	#include <libssh/callbacks.h>
18	#include <libssh/libssh.h>
19	#include <libssh/server.h>
20
21	enum test_ssh_server_constant_t
22	{
23	BUF_SIZE = 2048,
24	};
25
26	static const char SSH_HOST_RSA_KEY_FILE[] = "../conf/ssh_host_rsa_key";
27	static const char SSH_HOST_ED25519_KEY_FILE[] = "../conf/ssh_host_ed25519_key";
28	static const char SSH_HOST_ECDSA_KEY_FILE[] = "../conf/ssh_host_ecdsa_key";
29
30	static const char USER[] = "test";
31	static const char PASSWORD[] = "123456";
32
33	static ssh_channel SSH_channel;
34	static int authenticated = 0;
35	static int tries = 0;
36	static int error = 0;
37
38	static int auth_password(ssh_session session, const char *user,
39	const char password, void userdata)
40	{
41	(void)userdata;
42
43	log_common("Authenticating user %s pwd %s", user, password);
44	if (strcmp(user, USER) == 0 && strcmp(password, PASSWORD) == 0)
45	{
46	authenticated = 1;
47	log_common("Authenticated");
48	return SSH_AUTH_SUCCESS;
49	}
50	if (tries >= 3)
51	{
52	log_error("Too many authentication tries");
53	ssh_disconnect(session);
54	error = 1;
55	return SSH_AUTH_DENIED;
56	}
57	tries++;
58	return SSH_AUTH_DENIED;
59	}
60
61	static int pty_request(ssh_session session, ssh_channel channel, const char *term,
62	int x, int y, int px, int py, void *userdata)
63	{
64	(void)session;
65	(void)channel;
66	(void)term;
67	(void)x;
68	(void)y;
69	(void)px;
70	(void)py;
71	(void)userdata;
72	log_common("Allocated terminal");
73	return 0;
74	}
75
76	static int shell_request(ssh_session session, ssh_channel channel, void *userdata)
77	{
78	(void)session;
79	(void)channel;
80	(void)userdata;
81	log_common("Allocated shell");
82	return 0;
83	}
84
85	struct ssh_channel_callbacks_struct channel_cb = {
86	.channel_pty_request_function = pty_request,
87	.channel_shell_request_function = shell_request};
88
89	static ssh_channel channel_open(ssh_session session, void *userdata)
90	{
91	(void)session;
92	(void)userdata;
93
94	if (SSH_channel != NULL)
95	return NULL;
96
97	log_common("Allocated session channel");
98	SSH_channel = ssh_channel_new(session);
99	ssh_callbacks_init(&channel_cb);
100	ssh_set_channel_callbacks(SSH_channel, &channel_cb);
101
102	return SSH_channel;
103	}
104
105	int ssh_server(const char *hostaddr, unsigned int port)
106	{
107	ssh_bind sshbind;
108	ssh_session session;
109	ssh_event event;
110
111	struct ssh_server_callbacks_struct cb = {
112	.userdata = NULL,
113	.auth_password_function = auth_password,
114	.channel_open_request_session_function = channel_open};
115
116	long int ssh_timeout = 0;
117
118	char buf[BUF_SIZE];
119	char host[128] = "";
120	int i, r;
121
122	int ssh_key_valid = 0;
123	int ssh_log_level = SSH_LOG_PROTOCOL;
124
125	ssh_init();
126
127	sshbind = ssh_bind_new();
128
129	if (ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY, SSH_HOST_RSA_KEY_FILE) < 0)
130	{
131	log_error("Error loading SSH RSA key: %s", SSH_HOST_RSA_KEY_FILE);
132	}
133	else
134	{
135	ssh_key_valid = 1;
136	}
137	if (ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY, SSH_HOST_ED25519_KEY_FILE) < 0)
138	{
139	log_error("Error loading SSH ED25519 key: %s", SSH_HOST_ED25519_KEY_FILE);
140	}
141	else
142	{
143	ssh_key_valid = 1;
144	}
145	if (ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY, SSH_HOST_ECDSA_KEY_FILE) < 0)
146	{
147	log_error("Error loading SSH ECDSA key: %s", SSH_HOST_ECDSA_KEY_FILE);
148	}
149	else
150	{
151	ssh_key_valid = 1;
152	}
153
154	if (!ssh_key_valid)
155	{
156	log_error("Error: no valid SSH host key");
157	ssh_bind_free(sshbind);
158	return -1;
159	}
160
161	if (ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDADDR, hostaddr) < 0 \|\|
162	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDPORT, &port) < 0 \|\|
163	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY_ALGORITHMS, "+ssh-ed25519,ecdsa-sha2-nistp256,ssh-rsa") < 0 \|\|
164	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_LOG_VERBOSITY, &ssh_log_level) < 0)
165	{
166	log_error("Error setting SSH bind options: %s", ssh_get_error(sshbind));
167	ssh_bind_free(sshbind);
168	return -1;
169	}
170
171	if (ssh_bind_listen(sshbind) < 0)
172	{
173	log_error("Error listening at SSH server port: %s", ssh_get_error(sshbind));
174	ssh_bind_free(sshbind);
175	return -1;
176	}
177
178	while (1)
179	{
180	session = ssh_new();
181
182	if (ssh_bind_accept(sshbind, session) == SSH_OK)
183	{
184	pid_t pid = fork();
185	switch (pid)
186	{
187	case 0:
188	ssh_bind_free(sshbind);
189
190	ssh_callbacks_init(&cb);
191	ssh_set_server_callbacks(session, &cb);
192
193	ssh_timeout = 60; // second
194	if (ssh_options_set(session, SSH_OPTIONS_TIMEOUT, &ssh_timeout) < 0)
195	{
196	log_error("Error setting SSH options: %s", ssh_get_error(session));
197	ssh_disconnect(session);
198	_exit(1);
199	}
200
201	if (ssh_handle_key_exchange(session))
202	{
203	log_error("ssh_handle_key_exchange: %s", ssh_get_error(session));
204	ssh_disconnect(session);
205	_exit(1);
206	}
207	ssh_set_auth_methods(session, SSH_AUTH_METHOD_PASSWORD \| SSH_AUTH_METHOD_GSSAPI_MIC);
208
209	event = ssh_event_new();
210	ssh_event_add_session(event, session);
211
212	while (!(authenticated && SSH_channel != NULL))
213	{
214	if (error)
215	break;
216	r = ssh_event_dopoll(event, -1);
217	if (r == SSH_ERROR)
218	{
219	log_error("Error : %s", ssh_get_error(session));
220	ssh_disconnect(session);
221	_exit(1);
222	}
223	}
224
225	if (error)
226	{
227	log_error("Error, exiting loop");
228	_exit(1);
229	}
230	else
231	{
232	log_common("Authenticated and got a channel");
233	}
234
235	ssh_timeout = 0;
236	if (ssh_options_set(session, SSH_OPTIONS_TIMEOUT, &ssh_timeout) < 0)
237	{
238	log_error("Error setting SSH options: %s", ssh_get_error(session));
239	ssh_disconnect(session);
240	_exit(1);
241	}
242
243	snprintf(buf, sizeof(buf), "Hello, welcome to the Sample SSH proxy.\nPlease select your destination: ");
244	ssh_channel_write(SSH_channel, buf, (uint32_t)strlen(buf));
245	do
246	{
247	i = ssh_channel_read(SSH_channel, buf, sizeof(buf), 0);
248	if (i > 0)
249	{
250	ssh_channel_write(SSH_channel, buf, (uint32_t)i);
251	if (strlen(host) + (size_t)i < sizeof(host))
252	{
253	strncat(host, buf, (size_t)i);
254	}
255	if (strchr(host, '\x0d'))
256	{
257	*strchr(host, '\x0d') = '\0';
258	ssh_channel_write(SSH_channel, "\n", 1);
259	break;
260	}
261	}
262	else
263	{
264	log_error("Error: %s", ssh_get_error(session));
265	_exit(1);
266	}
267	} while (i > 0);
268	snprintf(buf, sizeof(buf), "Trying to connect to \"%s\"\n", host);
269	ssh_channel_write(SSH_channel, buf, (uint32_t)strlen(buf));
270	log_common("%s", buf);
271
272	ssh_disconnect(session);
273	ssh_free(session);
274
275	_exit(0);
276	case -1:
277	log_error("Failed to fork");
278	break;
279	}
280	}
281	else
282	{
283	log_error("%s", ssh_get_error(sshbind));
284	}
285
286	/* Since the session has been passed to a child fork, do some cleaning
287	* up at the parent process. */
288	ssh_disconnect(session);
289	ssh_free(session);
290	}
291
292	ssh_bind_free(sshbind);
293	ssh_finalize();
294
295	return 0;
296	}
297
298	int main(int argc, char *argv[])
299	{
300	if (log_begin("../log/bbsd.log", "../log/error.log") < 0)
301	{
302	printf("Open log error\n");
303	return -1;
304	}
305
306	log_common_redir(STDOUT_FILENO);
307	log_error_redir(STDERR_FILENO);
308
309	ssh_server("0.0.0.0", 2322);
310
311	log_end();
312
313	return 0;
314	}
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