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	sysadm	1.12	/* SPDX-License-Identifier: GPL-3.0-or-later */
2			/*
3			* test_ssh_server
4			* - tester for network server with SSH support
5			*
6	sysadm	1.13	* Copyright (C) 2004-2025 Leaflet <leaflet@leafok.com>
7	sysadm	1.12	*/
8	sysadm	1.8
9			// This test was written based on libssh example/proxy.c
10	sysadm	1.7
11	sysadm	1.15	#ifdef HAVE_CONFIG_H
12			#include "config.h"
13			#endif
14
15	sysadm	1.1	#include "log.h"
16			#include <stdio.h>
17	sysadm	1.9	#include <libssh/callbacks.h>
18	sysadm	1.1	#include <libssh/libssh.h>
19			#include <libssh/server.h>
20
21	sysadm	1.14	enum test_ssh_server_constant_t
22			{
23			BUF_SIZE = 2048,
24			};
25	sysadm	1.2
26	sysadm	1.16	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	sysadm	1.2
29	sysadm	1.14	static const char USER[] = "test";
30			static const char PASSWORD[] = "123456";
31	sysadm	1.2
32	sysadm	1.4	static ssh_channel SSH_channel;
33	sysadm	1.2	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	sysadm	1.1	{
40	sysadm	1.2	(void)userdata;
41
42	sysadm	1.3	log_common("Authenticating user %s pwd %s\n", user, password);
43	sysadm	1.2	if (strcmp(user, USER) == 0 && strcmp(password, PASSWORD) == 0)
44	sysadm	1.1	{
45	sysadm	1.2	authenticated = 1;
46	sysadm	1.3	log_common("Authenticated\n");
47	sysadm	1.1	return SSH_AUTH_SUCCESS;
48			}
49	sysadm	1.2	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	sysadm	1.3	log_common("Allocated terminal\n");
72	sysadm	1.2	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	sysadm	1.3	log_common("Allocated shell\n");
81	sysadm	1.2	return 0;
82			}
83	sysadm	1.4
84	sysadm	1.2	struct ssh_channel_callbacks_struct channel_cb = {
85			.channel_pty_request_function = pty_request,
86			.channel_shell_request_function = shell_request};
87
88	sysadm	1.11	static ssh_channel channel_open(ssh_session session, void *userdata)
89	sysadm	1.2	{
90			(void)session;
91			(void)userdata;
92	sysadm	1.1
93	sysadm	1.4	if (SSH_channel != NULL)
94	sysadm	1.2	return NULL;
95
96	sysadm	1.3	log_common("Allocated session channel\n");
97	sysadm	1.4	SSH_channel = ssh_channel_new(session);
98	sysadm	1.2	ssh_callbacks_init(&channel_cb);
99	sysadm	1.4	ssh_set_channel_callbacks(SSH_channel, &channel_cb);
100	sysadm	1.2
101	sysadm	1.4	return SSH_channel;
102	sysadm	1.1	}
103
104			int ssh_server(const char *hostaddr, unsigned int port)
105			{
106	sysadm	1.4	ssh_bind sshbind;
107	sysadm	1.2	ssh_session session;
108			ssh_event event;
109
110	sysadm	1.1	struct ssh_server_callbacks_struct cb = {
111			.userdata = NULL,
112	sysadm	1.2	.auth_password_function = auth_password,
113	sysadm	1.11	.channel_open_request_session_function = channel_open};
114	sysadm	1.2
115	sysadm	1.10	long int ssh_timeout = 0;
116
117	sysadm	1.2	char buf[BUF_SIZE];
118			char host[128] = "";
119			int i, r;
120
121	sysadm	1.16	int ssh_key_valid = 0;
122	sysadm	1.6	int ssh_log_level = SSH_LOG_PROTOCOL;
123	sysadm	1.1
124			ssh_init();
125
126			sshbind = ssh_bind_new();
127
128	sysadm	1.16	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	sysadm	1.1	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	sysadm	1.16	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY_ALGORITHMS, "ssh-rsa,rsa-sha2-512,rsa-sha2-256,ssh-ed25519") < 0 \|\|
155	sysadm	1.1	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	sysadm	1.2	ssh_bind_free(sshbind);
159	sysadm	1.1	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	sysadm	1.2	ssh_bind_free(sshbind);
166	sysadm	1.1	return -1;
167			}
168
169			while (1)
170			{
171			session = ssh_new();
172
173	sysadm	1.2	if (ssh_bind_accept(sshbind, session) == SSH_OK)
174	sysadm	1.1	{
175	sysadm	1.2	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	sysadm	1.10	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	sysadm	1.2	if (ssh_handle_key_exchange(session))
193			{
194			log_error("ssh_handle_key_exchange: %s\n", ssh_get_error(session));
195	sysadm	1.10	ssh_disconnect(session);
196			_exit(1);
197	sysadm	1.2	}
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	sysadm	1.4	while (!(authenticated && SSH_channel != NULL))
204	sysadm	1.2	{
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	sysadm	1.3	log_common("Authenticated and got a channel\n");
224	sysadm	1.2	}
225
226	sysadm	1.10	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	sysadm	1.2	snprintf(buf, sizeof(buf), "Hello, welcome to the Sample SSH proxy.\r\nPlease select your destination: ");
235	sysadm	1.4	ssh_channel_write(SSH_channel, buf, (uint32_t)strlen(buf));
236	sysadm	1.2	do
237			{
238	sysadm	1.4	i = ssh_channel_read(SSH_channel, buf, sizeof(buf), 0);
239	sysadm	1.2	if (i > 0)
240			{
241	sysadm	1.4	ssh_channel_write(SSH_channel, buf, (uint32_t)i);
242	sysadm	1.2	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	sysadm	1.4	ssh_channel_write(SSH_channel, "\n", 1);
250	sysadm	1.2	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	sysadm	1.4	ssh_channel_write(SSH_channel, buf, (uint32_t)strlen(buf));
261	sysadm	1.3	log_common("%s", buf);
262	sysadm	1.2
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	sysadm	1.1	}
272	sysadm	1.2	else
273	sysadm	1.1	{
274	sysadm	1.2	log_error("%s\n", ssh_get_error(sshbind));
275	sysadm	1.1	}
276
277	sysadm	1.2	/* Since the session has been passed to a child fork, do some cleaning
278			* up at the parent process. */
279	sysadm	1.1	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	sysadm	1.3	log_common_redir(STDOUT_FILENO);
298			log_error_redir(STDERR_FILENO);
299	sysadm	1.1
300			ssh_server("0.0.0.0", 2322);
301
302			log_end();
303
304			return 0;
305			}
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