aboutsummaryrefslogtreecommitdiffstats
path: root/extcap/ssh-base.c
blob: 1799887d90c719af84d03d1256daf0554861577c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
/* ssh-base.c
 * ssh-base has base utility functions to connect to hosts via ssh
 *
 * Copyright 2016, Dario Lombardo
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0+
 */

#include "config.h"

#include "ssh-base.h"

#include <extcap/extcap-base.h>
#include <log.h>
#include <string.h>

ssh_session create_ssh_connection(const char* hostname, const guint16 port, const char* username,
	const char* password, const char* sshkey_path, const char* sshkey_passphrase, char** err_info)
{
	ssh_session sshs;

	/* Open session and set options */
	sshs = ssh_new();
	if (sshs == NULL) {
		*err_info = g_strdup("Can't create ssh session");
		return NULL;
	}

	if (!hostname) {
		*err_info = g_strdup("Hostname needed");
		goto failure;
	}

	if (ssh_options_set(sshs, SSH_OPTIONS_HOST, hostname)) {
		*err_info = g_strdup_printf("Can't set the hostname: %s", hostname);
		goto failure;
	}

	if (port != 0) {
		if (ssh_options_set(sshs, SSH_OPTIONS_PORT, &port)) {
			*err_info = g_strdup_printf("Can't set the port: %d", port);
			goto failure;
		}
	}

	if (!username)
		username = g_get_user_name();

	if (ssh_options_set(sshs, SSH_OPTIONS_USER, username)) {
		*err_info = g_strdup_printf("Can't set the username: %s", username);
		goto failure;
	}

	g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_INFO, "Opening ssh connection to %s@%s:%u", username, hostname, port);

	/* Connect to server */
	if (ssh_connect(sshs) != SSH_OK) {
		*err_info = g_strdup_printf("Error connecting to %s@%s:%u (%s)", username, hostname, port,
			ssh_get_error(sshs));
		goto failure;
	}

#ifdef HAVE_LIBSSH_USERAUTH_AGENT
	g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_INFO, "Connecting using ssh-agent...");
	/* Try to authenticate using ssh agent */
	if (ssh_userauth_agent(sshs, NULL) == SSH_AUTH_SUCCESS) {
		g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_INFO, "done");
		return sshs;
	}
	g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_INFO, "failed");
#endif

	/* If a public key path has been provided, try to authenticate using it */
	if (sshkey_path) {
		ssh_key pkey = ssh_key_new();
		int ret;

		g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_INFO, "Connecting using public key in %s...", sshkey_path);
		ret = ssh_pki_import_privkey_file(sshkey_path, sshkey_passphrase, NULL, NULL, &pkey);

		if (ret == SSH_OK) {
			if (ssh_userauth_publickey(sshs, NULL, pkey) == SSH_AUTH_SUCCESS) {
				g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_INFO, "done");
				ssh_key_free(pkey);
				return sshs;
			}
		}
		ssh_key_free(pkey);
		g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_INFO, "failed (%s)", ssh_get_error(sshs));
	}

	/* Try to authenticate using standard public key */
	g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_INFO, "Connecting using standard public key...");
	if (ssh_userauth_publickey_auto(sshs, NULL, NULL) == SSH_AUTH_SUCCESS) {
		g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_INFO, "done");
		return sshs;
	}
	g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_INFO, "failed");

	/* If a password has been provided and all previous attempts failed, try to use it */
	if (password) {
		g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_INFO, "Connecting using password...");
		if (ssh_userauth_password(sshs, username, password) == SSH_AUTH_SUCCESS) {
			g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_INFO, "done");
			return sshs;
		}
		g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_INFO, "failed");
	}

	*err_info = g_strdup_printf("Can't find a valid authentication. Disconnecting.");

	/* All authentication failed. Disconnect and return */
	ssh_disconnect(sshs);

failure:
	ssh_free(sshs);
	return NULL;
}

int ssh_channel_printf(ssh_channel channel, const char* fmt, ...)
{
	gchar* buf;
	va_list arg;
	int ret = EXIT_SUCCESS;

	va_start(arg, fmt);
	buf = g_strdup_vprintf(fmt, arg);
	if (ssh_channel_write(channel, buf, (guint32)strlen(buf)) == SSH_ERROR)
		ret = EXIT_FAILURE;
	va_end(arg);
	g_free(buf);

	return ret;
}

void ssh_cleanup(ssh_session* sshs, ssh_channel* channel)
{
	if (*channel) {
		ssh_channel_send_eof(*channel);
		ssh_channel_close(*channel);
		ssh_channel_free(*channel);
		*channel = NULL;
	}

	if (*sshs) {
		ssh_disconnect(*sshs);
		ssh_free(*sshs);
		*sshs = NULL;
	}
}

/*
 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 8
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 * :indentSize=8:tabSize=8:noTabs=false:
 */