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

#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_KEYFILE[] = "../conf/ssh_host_rsa_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_log_level = SSH_LOG_PROTOCOL;

        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_RSA_KEYFILE) < 0 ||
                ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY_ALGORITHMS, "ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256") < 0 ||
                ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_PUBKEY_ACCEPTED_KEY_TYPES, "ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256") < 0 ||
                ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_KEY_EXCHANGE, "curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1") < 0 ||
                ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HMAC_C_S, "umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1") < 0 ||
                ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HMAC_S_C, "umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1") < 0 ||
                ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_CIPHERS_C_S, "chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com") < 0 ||
                ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_CIPHERS_S_C, "chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com") < 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	#include "log.h"
12	#include <stdio.h>
13	#include <libssh/callbacks.h>
14	#include <libssh/libssh.h>
15	#include <libssh/server.h>
16
17	enum test_ssh_server_constant_t
18	{
19	BUF_SIZE = 2048,
20	};
21
22	static const char SSH_HOST_RSA_KEYFILE[] = "../conf/ssh_host_rsa_key";
23
24	static const char USER[] = "test";
25	static const char PASSWORD[] = "123456";
26
27	static ssh_channel SSH_channel;
28	static int authenticated = 0;
29	static int tries = 0;
30	static int error = 0;
31
32	static int auth_password(ssh_session session, const char *user,
33	const char password, void userdata)
34	{
35	(void)userdata;
36
37	log_common("Authenticating user %s pwd %s\n", user, password);
38	if (strcmp(user, USER) == 0 && strcmp(password, PASSWORD) == 0)
39	{
40	authenticated = 1;
41	log_common("Authenticated\n");
42	return SSH_AUTH_SUCCESS;
43	}
44	if (tries >= 3)
45	{
46	log_error("Too many authentication tries\n");
47	ssh_disconnect(session);
48	error = 1;
49	return SSH_AUTH_DENIED;
50	}
51	tries++;
52	return SSH_AUTH_DENIED;
53	}
54
55	static int pty_request(ssh_session session, ssh_channel channel, const char *term,
56	int x, int y, int px, int py, void *userdata)
57	{
58	(void)session;
59	(void)channel;
60	(void)term;
61	(void)x;
62	(void)y;
63	(void)px;
64	(void)py;
65	(void)userdata;
66	log_common("Allocated terminal\n");
67	return 0;
68	}
69
70	static int shell_request(ssh_session session, ssh_channel channel, void *userdata)
71	{
72	(void)session;
73	(void)channel;
74	(void)userdata;
75	log_common("Allocated shell\n");
76	return 0;
77	}
78
79	struct ssh_channel_callbacks_struct channel_cb = {
80	.channel_pty_request_function = pty_request,
81	.channel_shell_request_function = shell_request};
82
83	static ssh_channel channel_open(ssh_session session, void *userdata)
84	{
85	(void)session;
86	(void)userdata;
87
88	if (SSH_channel != NULL)
89	return NULL;
90
91	log_common("Allocated session channel\n");
92	SSH_channel = ssh_channel_new(session);
93	ssh_callbacks_init(&channel_cb);
94	ssh_set_channel_callbacks(SSH_channel, &channel_cb);
95
96	return SSH_channel;
97	}
98
99	int ssh_server(const char *hostaddr, unsigned int port)
100	{
101	ssh_bind sshbind;
102	ssh_session session;
103	ssh_event event;
104
105	struct ssh_server_callbacks_struct cb = {
106	.userdata = NULL,
107	.auth_password_function = auth_password,
108	.channel_open_request_session_function = channel_open};
109
110	long int ssh_timeout = 0;
111
112	char buf[BUF_SIZE];
113	char host[128] = "";
114	int i, r;
115
116	int ssh_log_level = SSH_LOG_PROTOCOL;
117
118	ssh_init();
119
120	sshbind = ssh_bind_new();
121
122	if (ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDADDR, hostaddr) < 0 \|\|
123	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDPORT, &port) < 0 \|\|
124	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY, SSH_HOST_RSA_KEYFILE) < 0 \|\|
125	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY_ALGORITHMS, "ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256") < 0 \|\|
126	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_PUBKEY_ACCEPTED_KEY_TYPES, "ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256") < 0 \|\|
127	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_KEY_EXCHANGE, "curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1") < 0 \|\|
128	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HMAC_C_S, "umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1") < 0 \|\|
129	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HMAC_S_C, "umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1") < 0 \|\|
130	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_CIPHERS_C_S, "chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com") < 0 \|\|
131	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_CIPHERS_S_C, "chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com") < 0 \|\|
132	ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_LOG_VERBOSITY, &ssh_log_level) < 0)
133	{
134	log_error("Error setting SSH bind options: %s\n", ssh_get_error(sshbind));
135	ssh_bind_free(sshbind);
136	return -1;
137	}
138
139	if (ssh_bind_listen(sshbind) < 0)
140	{
141	log_error("Error listening at SSH server port: %s\n", ssh_get_error(sshbind));
142	ssh_bind_free(sshbind);
143	return -1;
144	}
145
146	while (1)
147	{
148	session = ssh_new();
149
150	if (ssh_bind_accept(sshbind, session) == SSH_OK)
151	{
152	pid_t pid = fork();
153	switch (pid)
154	{
155	case 0:
156	ssh_bind_free(sshbind);
157
158	ssh_callbacks_init(&cb);
159	ssh_set_server_callbacks(session, &cb);
160
161	ssh_timeout = 60; // second
162	if (ssh_options_set(session, SSH_OPTIONS_TIMEOUT, &ssh_timeout) < 0)
163	{
164	log_error("Error setting SSH options: %s\n", ssh_get_error(session));
165	ssh_disconnect(session);
166	_exit(1);
167	}
168
169	if (ssh_handle_key_exchange(session))
170	{
171	log_error("ssh_handle_key_exchange: %s\n", ssh_get_error(session));
172	ssh_disconnect(session);
173	_exit(1);
174	}
175	ssh_set_auth_methods(session, SSH_AUTH_METHOD_PASSWORD \| SSH_AUTH_METHOD_GSSAPI_MIC);
176
177	event = ssh_event_new();
178	ssh_event_add_session(event, session);
179
180	while (!(authenticated && SSH_channel != NULL))
181	{
182	if (error)
183	break;
184	r = ssh_event_dopoll(event, -1);
185	if (r == SSH_ERROR)
186	{
187	log_error("Error : %s\n", ssh_get_error(session));
188	ssh_disconnect(session);
189	_exit(1);
190	}
191	}
192
193	if (error)
194	{
195	log_error("Error, exiting loop\n");
196	_exit(1);
197	}
198	else
199	{
200	log_common("Authenticated and got a channel\n");
201	}
202
203	ssh_timeout = 0;
204	if (ssh_options_set(session, SSH_OPTIONS_TIMEOUT, &ssh_timeout) < 0)
205	{
206	log_error("Error setting SSH options: %s\n", ssh_get_error(session));
207	ssh_disconnect(session);
208	_exit(1);
209	}
210
211	snprintf(buf, sizeof(buf), "Hello, welcome to the Sample SSH proxy.\r\nPlease select your destination: ");
212	ssh_channel_write(SSH_channel, buf, (uint32_t)strlen(buf));
213	do
214	{
215	i = ssh_channel_read(SSH_channel, buf, sizeof(buf), 0);
216	if (i > 0)
217	{
218	ssh_channel_write(SSH_channel, buf, (uint32_t)i);
219	if (strlen(host) + (size_t)i < sizeof(host))
220	{
221	strncat(host, buf, (size_t)i);
222	}
223	if (strchr(host, '\x0d'))
224	{
225	*strchr(host, '\x0d') = '\0';
226	ssh_channel_write(SSH_channel, "\n", 1);
227	break;
228	}
229	}
230	else
231	{
232	log_error("Error: %s\n", ssh_get_error(session));
233	_exit(1);
234	}
235	} while (i > 0);
236	snprintf(buf, sizeof(buf), "Trying to connect to \"%s\"\r\n", host);
237	ssh_channel_write(SSH_channel, buf, (uint32_t)strlen(buf));
238	log_common("%s", buf);
239
240	ssh_disconnect(session);
241	ssh_free(session);
242
243	_exit(0);
244	case -1:
245	log_error("Failed to fork\n");
246	break;
247	}
248	}
249	else
250	{
251	log_error("%s\n", ssh_get_error(sshbind));
252	}
253
254	/* Since the session has been passed to a child fork, do some cleaning
255	* up at the parent process. */
256	ssh_disconnect(session);
257	ssh_free(session);
258	}
259
260	ssh_bind_free(sshbind);
261	ssh_finalize();
262
263	return 0;
264	}
265
266	int main(int argc, char *argv[])
267	{
268	if (log_begin("../log/bbsd.log", "../log/error.log") < 0)
269	{
270	printf("Open log error\n");
271	return -1;
272	}
273
274	log_common_redir(STDOUT_FILENO);
275	log_error_redir(STDERR_FILENO);
276
277	ssh_server("0.0.0.0", 2322);
278
279	log_end();
280
281	return 0;
282	}
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