summaryrefslogtreecommitdiff
path: root/sample/sample-plugins/keying-material-exporter-demo/keyingmaterialexporter.c
blob: 5d3ca14ded73b93908b89d5b4eefb3eb50f95249 (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
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
/*
 *  OpenVPN -- An application to securely tunnel IP networks
 *             over a single TCP/UDP port, with support for SSL/TLS-based
 *             session authentication and key exchange,
 *             packet encryption, packet authentication, and
 *             packet compression.
 *
 *  Copyright (C) 2002-2018 OpenVPN Inc <sales@openvpn.net>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

/*
 * This file implements a Sample (HTTP) SSO OpenVPN plugin module
 *
 * See the README file for build instructions.
 */

#define ENABLE_CRYPTO

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "openvpn-plugin.h"

#ifndef MAXPATH
#define MAXPATH 1024
#endif

#define ovpn_err(fmt, ...) \
    plugin->log(PLOG_ERR,   "SSO", fmt, ## __VA_ARGS__)
#define ovpn_dbg(fmt, ...) \
    plugin->log(PLOG_DEBUG, "SSO", fmt, ## __VA_ARGS__)
#define ovpn_note(fmt, ...) \
    plugin->log(PLOG_NOTE,  "SSO", fmt, ## __VA_ARGS__)

enum endpoint { CLIENT = 1, SERVER = 2 };

struct plugin {
    plugin_log_t log;
    enum endpoint type;
    int mask;
};

struct session {
    char user[48];
    char key [48];
};

/*
 * Given an environmental variable name, search
 * the envp array for its value, returning it
 * if found or NULL otherwise.
 */

static const char *
get_env(const char *name, const char *envp[])
{
    if (envp)
    {
        int i;
        const int namelen = strlen(name);
        for (i = 0; envp[i]; ++i)
        {
            if (!strncmp(envp[i], name, namelen))
            {
                const char *cp = envp[i] + namelen;
                if (*cp == '=')
                {
                    return cp + 1;
                }
            }
        }
    }
    return NULL;
}

OPENVPN_EXPORT int
openvpn_plugin_open_v3(const int version,
                       struct openvpn_plugin_args_open_in const *args,
                       struct openvpn_plugin_args_open_return *rv)
{
    struct plugin *plugin = calloc(1, sizeof(*plugin));

    plugin->type = get_env("remote_1", args->envp) ? CLIENT : SERVER;
    plugin->log  = args->callbacks->plugin_log;

    plugin->mask  = OPENVPN_PLUGIN_MASK(OPENVPN_PLUGIN_TLS_FINAL);
    plugin->mask |= OPENVPN_PLUGIN_MASK(OPENVPN_PLUGIN_TLS_VERIFY);

    ovpn_note("vpn endpoint type=%s",plugin->type == CLIENT ? "client" : "server");

    rv->type_mask = plugin->mask;
    rv->handle = (void *)plugin;

    return OPENVPN_PLUGIN_FUNC_SUCCESS;
}

static void
session_user_set(struct session *sess, X509 *x509)
{
    int fn_nid;
    ASN1_OBJECT *fn;
    ASN1_STRING *val;
    X509_NAME *x509_name;
    X509_NAME_ENTRY *ent;
    const char *objbuf;

    x509_name = X509_get_subject_name(x509);
    int i, n = X509_NAME_entry_count(x509_name);
    for (i = 0; i < n; ++i)
    {
        if (!(ent = X509_NAME_get_entry(x509_name, i)))
        {
            continue;
        }
        if (!(fn = X509_NAME_ENTRY_get_object(ent)))
        {
            continue;
        }
        if (!(val = X509_NAME_ENTRY_get_data(ent)))
        {
            continue;
        }
        if ((fn_nid = OBJ_obj2nid(fn)) == NID_undef)
        {
            continue;
        }
        if (!(objbuf = OBJ_nid2sn(fn_nid)))
        {
            continue;
        }
        unsigned char *buf = NULL;
        if (ASN1_STRING_to_UTF8(&buf, val) < 0)
        {
            continue;
        }

        if (!strncasecmp(objbuf, "CN", 2))
        {
            snprintf(sess->user, sizeof(sess->user) - 1, (char *)buf);
        }

        OPENSSL_free(buf);
    }
}

static int
tls_verify(struct openvpn_plugin_args_func_in const *args)
{
    struct plugin *plugin = (struct plugin  *)args->handle;
    struct session *sess  = (struct session *)args->per_client_context;

    /* we store cert subject for the server end point only */
    if (plugin->type != SERVER)
    {
        return OPENVPN_PLUGIN_FUNC_SUCCESS;
    }

    if (!args->current_cert)
    {
        ovpn_err("this example plugin requires client certificate");
        return OPENVPN_PLUGIN_FUNC_ERROR;
    }

    session_user_set(sess, args->current_cert);

    return OPENVPN_PLUGIN_FUNC_SUCCESS;
}

static void
file_store(char *file, char *content)
{
    FILE *f;
    if (!(f = fopen(file, "w+")))
    {
        return;
    }

    fprintf(f, "%s", content);
    fclose(f);
}

static void
server_store(struct openvpn_plugin_args_func_in const *args)
{
    struct plugin *plugin = (struct plugin  *)args->handle;
    struct session *sess  = (struct session *)args->per_client_context;

    char file[MAXPATH];
    snprintf(file, sizeof(file) - 1, "/tmp/openvpn_sso_%s", sess->key);
    ovpn_note("app session file: %s", file);
    file_store(file, sess->user);
}

static void
client_store(struct openvpn_plugin_args_func_in const *args)
{
    struct plugin *plugin = (struct plugin  *)args->handle;
    struct session *sess  = (struct session *)args->per_client_context;

    char *file = "/tmp/openvpn_sso_user";
    ovpn_note("app session file: %s", file);
    file_store(file, sess->key);
}

static int
tls_final(struct openvpn_plugin_args_func_in const *args,
          struct openvpn_plugin_args_func_return *rv)
{
    struct plugin *plugin = (struct plugin  *)args->handle;
    struct session *sess  = (struct session *)args->per_client_context;

    const char *key;
    if (!(key = get_env("exported_keying_material", args->envp)))
    {
        return OPENVPN_PLUGIN_FUNC_ERROR;
    }

    snprintf(sess->key, sizeof(sess->key) - 1, "%s", key);
    ovpn_note("app session key:  %s", sess->key);

    switch (plugin->type) {
        case SERVER:
            server_store(args);
            break;

        case CLIENT:
            client_store(args);
            return OPENVPN_PLUGIN_FUNC_SUCCESS;
    }

    ovpn_note("app session user: %s", sess->user);
    return OPENVPN_PLUGIN_FUNC_SUCCESS;
}

OPENVPN_EXPORT int
openvpn_plugin_func_v3(const int version,
                       struct openvpn_plugin_args_func_in const *args,
                       struct openvpn_plugin_args_func_return *rv)
{
    switch (args->type) {
        case OPENVPN_PLUGIN_TLS_VERIFY:
            return tls_verify(args);

        case OPENVPN_PLUGIN_TLS_FINAL:
            return tls_final(args, rv);
    }
    return OPENVPN_PLUGIN_FUNC_SUCCESS;
}

OPENVPN_EXPORT void *
openvpn_plugin_client_constructor_v1(openvpn_plugin_handle_t handle)
{
    struct plugin *plugin = (struct plugin *)handle;
    struct session *sess  = calloc(1, sizeof(*sess));

    ovpn_note("app session created");

    return (void *)sess;
}

OPENVPN_EXPORT void
openvpn_plugin_client_destructor_v1(openvpn_plugin_handle_t handle, void *ctx)
{
    struct plugin *plugin = (struct plugin *)handle;
    struct session *sess  = (struct session *)ctx;

    ovpn_note("app session key: %s", sess->key);
    ovpn_note("app session destroyed");

    free(sess);
}

OPENVPN_EXPORT void
openvpn_plugin_close_v1(openvpn_plugin_handle_t handle)
{
    struct plugin *plugin = (struct plugin *)handle;
    free(plugin);
}