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) 2004-2025  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 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\n", user, password);
        if (strcmp(user, USER) == 0 && strcmp(password, PASSWORD) == 0)
        {
                authenticated = 1;
                log_common("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_common("Allocated terminal\n");
        return 0;
}

static int shell_request(ssh_session session, ssh_channel channel, void *userdata)
{
        (void)session;
        (void)channel;
        (void)userdata;
        log_common("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 channel_open(ssh_session session, void *userdata)
{
        (void)session;
        (void)userdata;

        if (SSH_channel != NULL)
                return NULL;

        log_common("Allocated session channel\n");
        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 setting SSH RSA key: %s\n", 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 setting SSH ED25519 key: %s\n", SSH_HOST_ED25519_KEY_FILE);
        }
        else
        {
                ssh_key_valid = 1;
        }

        if (!ssh_key_valid)
        {
                log_error("Error: no valid SSH host key\n");
                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-rsa,rsa-sha2-512,rsa-sha2-256,ssh-ed25519") < 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);

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

                                if (ssh_handle_key_exchange(session))
                                {
                                        log_error("ssh_handle_key_exchange: %s\n", 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\n", ssh_get_error(session));
                                                ssh_disconnect(session);
                                                _exit(1);
                                        }
                                }

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

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

                                snprintf(buf, sizeof(buf), "Hello, welcome to the Sample SSH proxy.\r\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\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(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\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_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) 2004-2025 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
29	static const char USER[] = "test";
30	static const char PASSWORD[] = "123456";
31
32	static ssh_channel SSH_channel;
33	static int authenticated = 0;
34	static int tries = 0;
35	static int error = 0;
36
37	static int auth_password(ssh_session session, const char *user,
38	const char password, void userdata)
39	{
40	(void)userdata;
41
42	log_common("Authenticating user %s pwd %s\n", user, password);
43	if (strcmp(user, USER) == 0 && strcmp(password, PASSWORD) == 0)
44	{
45	authenticated = 1;
46	log_common("Authenticated\n");
47	return SSH_AUTH_SUCCESS;
48	}
49	if (tries >= 3)
50	{
51	log_error("Too many authentication tries\n");
52	ssh_disconnect(session);
53	error = 1;
54	return SSH_AUTH_DENIED;
55	}
56	tries++;
57	return SSH_AUTH_DENIED;
58	}
59
60	static int pty_request(ssh_session session, ssh_channel channel, const char *term,
61	int x, int y, int px, int py, void *userdata)
62	{
63	(void)session;
64	(void)channel;
65	(void)term;
66	(void)x;
67	(void)y;
68	(void)px;
69	(void)py;
70	(void)userdata;
71	log_common("Allocated terminal\n");
72	return 0;
73	}
74
75	static int shell_request(ssh_session session, ssh_channel channel, void *userdata)
76	{
77	(void)session;
78	(void)channel;
79	(void)userdata;
80	log_common("Allocated shell\n");
81	return 0;
82	}
83
84	struct ssh_channel_callbacks_struct channel_cb = {
85	.channel_pty_request_function = pty_request,
86	.channel_shell_request_function = shell_request};
87
88	static ssh_channel channel_open(ssh_session session, void *userdata)
89	{
90	(void)session;
91	(void)userdata;
92
93	if (SSH_channel != NULL)
94	return NULL;
95
96	log_common("Allocated session channel\n");
97	SSH_channel = ssh_channel_new(session);
98	ssh_callbacks_init(&channel_cb);
99	ssh_set_channel_callbacks(SSH_channel, &channel_cb);
100
101	return SSH_channel;
102	}
103
104	int ssh_server(const char *hostaddr, unsigned int port)
105	{
106	ssh_bind sshbind;
107	ssh_session session;
108	ssh_event event;
109
110	struct ssh_server_callbacks_struct cb = {
111	.userdata = NULL,
112	.auth_password_function = auth_password,
113	.channel_open_request_session_function = channel_open};
114
115	long int ssh_timeout = 0;
116
117	char buf[BUF_SIZE];
118	char host[128] = "";
119	int i, r;
120
121	int ssh_key_valid = 0;
122	int ssh_log_level = SSH_LOG_PROTOCOL;
123
124	ssh_init();
125
126	sshbind = ssh_bind_new();
127
128	if (ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY, SSH_HOST_RSA_KEY_FILE) < 0)
129	{
130	log_error("Error setting SSH RSA key: %s\n", SSH_HOST_RSA_KEY_FILE);
131	}
132	else
133	{
134	ssh_key_valid = 1;
135	}
136	if (ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY, SSH_HOST_ED25519_KEY_FILE) < 0)
137	{
138	log_error("Error setting SSH ED25519 key: %s\n", SSH_HOST_ED25519_KEY_FILE);
139	}
140	else
141	{
142	ssh_key_valid = 1;
143	}
144
145	if (!ssh_key_valid)
146	{
147	log_error("Error: no valid SSH host key\n");
148	ssh_bind_free(sshbind);
149	return -1;
150	}
151
152	if (ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDADDR, hostaddr) < 0 \|\|
153	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDPORT, &port) < 0 \|\|
154	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY_ALGORITHMS, "ssh-rsa,rsa-sha2-512,rsa-sha2-256,ssh-ed25519") < 0 \|\|
155	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_LOG_VERBOSITY, &ssh_log_level) < 0)
156	{
157	log_error("Error setting SSH bind options: %s\n", ssh_get_error(sshbind));
158	ssh_bind_free(sshbind);
159	return -1;
160	}
161
162	if (ssh_bind_listen(sshbind) < 0)
163	{
164	log_error("Error listening at SSH server port: %s\n", ssh_get_error(sshbind));
165	ssh_bind_free(sshbind);
166	return -1;
167	}
168
169	while (1)
170	{
171	session = ssh_new();
172
173	if (ssh_bind_accept(sshbind, session) == SSH_OK)
174	{
175	pid_t pid = fork();
176	switch (pid)
177	{
178	case 0:
179	ssh_bind_free(sshbind);
180
181	ssh_callbacks_init(&cb);
182	ssh_set_server_callbacks(session, &cb);
183
184	ssh_timeout = 60; // second
185	if (ssh_options_set(session, SSH_OPTIONS_TIMEOUT, &ssh_timeout) < 0)
186	{
187	log_error("Error setting SSH options: %s\n", ssh_get_error(session));
188	ssh_disconnect(session);
189	_exit(1);
190	}
191
192	if (ssh_handle_key_exchange(session))
193	{
194	log_error("ssh_handle_key_exchange: %s\n", ssh_get_error(session));
195	ssh_disconnect(session);
196	_exit(1);
197	}
198	ssh_set_auth_methods(session, SSH_AUTH_METHOD_PASSWORD \| SSH_AUTH_METHOD_GSSAPI_MIC);
199
200	event = ssh_event_new();
201	ssh_event_add_session(event, session);
202
203	while (!(authenticated && SSH_channel != NULL))
204	{
205	if (error)
206	break;
207	r = ssh_event_dopoll(event, -1);
208	if (r == SSH_ERROR)
209	{
210	log_error("Error : %s\n", ssh_get_error(session));
211	ssh_disconnect(session);
212	_exit(1);
213	}
214	}
215
216	if (error)
217	{
218	log_error("Error, exiting loop\n");
219	_exit(1);
220	}
221	else
222	{
223	log_common("Authenticated and got a channel\n");
224	}
225
226	ssh_timeout = 0;
227	if (ssh_options_set(session, SSH_OPTIONS_TIMEOUT, &ssh_timeout) < 0)
228	{
229	log_error("Error setting SSH options: %s\n", ssh_get_error(session));
230	ssh_disconnect(session);
231	_exit(1);
232	}
233
234	snprintf(buf, sizeof(buf), "Hello, welcome to the Sample SSH proxy.\r\nPlease select your destination: ");
235	ssh_channel_write(SSH_channel, buf, (uint32_t)strlen(buf));
236	do
237	{
238	i = ssh_channel_read(SSH_channel, buf, sizeof(buf), 0);
239	if (i > 0)
240	{
241	ssh_channel_write(SSH_channel, buf, (uint32_t)i);
242	if (strlen(host) + (size_t)i < sizeof(host))
243	{
244	strncat(host, buf, (size_t)i);
245	}
246	if (strchr(host, '\x0d'))
247	{
248	*strchr(host, '\x0d') = '\0';
249	ssh_channel_write(SSH_channel, "\n", 1);
250	break;
251	}
252	}
253	else
254	{
255	log_error("Error: %s\n", ssh_get_error(session));
256	_exit(1);
257	}
258	} while (i > 0);
259	snprintf(buf, sizeof(buf), "Trying to connect to \"%s\"\r\n", host);
260	ssh_channel_write(SSH_channel, buf, (uint32_t)strlen(buf));
261	log_common("%s", buf);
262
263	ssh_disconnect(session);
264	ssh_free(session);
265
266	_exit(0);
267	case -1:
268	log_error("Failed to fork\n");
269	break;
270	}
271	}
272	else
273	{
274	log_error("%s\n", ssh_get_error(sshbind));
275	}
276
277	/* Since the session has been passed to a child fork, do some cleaning
278	* up at the parent process. */
279	ssh_disconnect(session);
280	ssh_free(session);
281	}
282
283	ssh_bind_free(sshbind);
284	ssh_finalize();
285
286	return 0;
287	}
288
289	int main(int argc, char *argv[])
290	{
291	if (log_begin("../log/bbsd.log", "../log/error.log") < 0)
292	{
293	printf("Open log error\n");
294	return -1;
295	}
296
297	log_common_redir(STDOUT_FILENO);
298	log_error_redir(STDERR_FILENO);
299
300	ssh_server("0.0.0.0", 2322);
301
302	log_end();
303
304	return 0;
305	}
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