1/*
2 * Copyright (c) 2002 - 2003
3 * NetGroup, Politecnico di Torino (Italy)
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the Politecnico di Torino nor the names of its
16 * contributors may be used to endorse or promote products derived from
17 * this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 *
31 */
32
33#ifdef HAVE_CONFIG_H
34#include <config.h>
35#endif
36
37#ifdef HAVE_OPENSSL
38#include <stdlib.h>
39
40#include "portability.h"
41
42#include "sslutils.h"
43
44static const char *ssl_keyfile = "";   //!< file containing the private key in PEM format
45static const char *ssl_certfile = "";  //!< file containing the server's certificate in PEM format
46static const char *ssl_rootfile = "";  //!< file containing the list of CAs trusted by the client
47// TODO: a way to set ssl_rootfile from the command line, or an envvar?
48
49// TODO: lock?
50static SSL_CTX *ctx;
51
52void ssl_set_certfile(const char *certfile)
53{
54	ssl_certfile = certfile;
55}
56
57void ssl_set_keyfile(const char *keyfile)
58{
59	ssl_keyfile = keyfile;
60}
61
62int ssl_init_once(int is_server, int enable_compression, char *errbuf, size_t errbuflen)
63{
64	static int inited = 0;
65	if (inited) return 0;
66
67	SSL_library_init();
68	SSL_load_error_strings();
69	OpenSSL_add_ssl_algorithms();
70	if (enable_compression)
71		SSL_COMP_get_compression_methods();
72
73	SSL_METHOD const *meth =
74	    is_server ? SSLv23_server_method() : SSLv23_client_method();
75	ctx = SSL_CTX_new(meth);
76	if (! ctx)
77	{
78		snprintf(errbuf, errbuflen, "Cannot get a new SSL context: %s", ERR_error_string(ERR_get_error(), NULL));
79		goto die;
80	}
81
82	SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY);
83
84	if (is_server)
85	{
86		char const *certfile = ssl_certfile[0] ? ssl_certfile : "cert.pem";
87		if (1 != SSL_CTX_use_certificate_file(ctx, certfile, SSL_FILETYPE_PEM))
88		{
89			snprintf(errbuf, errbuflen, "Cannot read certificate file %s: %s", certfile, ERR_error_string(ERR_get_error(), NULL));
90			goto die;
91		}
92
93		char const *keyfile = ssl_keyfile[0] ? ssl_keyfile : "key.pem";
94		if (1 != SSL_CTX_use_PrivateKey_file(ctx, keyfile, SSL_FILETYPE_PEM))
95		{
96			snprintf(errbuf, errbuflen, "Cannot read private key file %s: %s", keyfile, ERR_error_string(ERR_get_error(), NULL));
97			goto die;
98		}
99	}
100	else
101	{
102		if (ssl_rootfile[0])
103		{
104			if (! SSL_CTX_load_verify_locations(ctx, ssl_rootfile, 0))
105			{
106				snprintf(errbuf, errbuflen, "Cannot read CA list from %s", ssl_rootfile);
107				goto die;
108			}
109		}
110		else
111		{
112			SSL_CTX_set_verify(ctx, SSL_VERIFY_NONE, NULL);
113		}
114	}
115
116#if 0
117	if (! RAND_load_file(RANDOM, 1024*1024))
118	{
119		snprintf(errbuf, errbuflen, "Cannot init random");
120		goto die;
121	}
122
123	if (is_server)
124	{
125		SSL_CTX_set_session_id_context(ctx, (void *)&s_server_session_id_context, sizeof(s_server_session_id_context));
126	}
127#endif
128
129	inited = 1;
130	return 0;
131
132die:
133	return -1;
134}
135
136SSL *ssl_promotion(int is_server, SOCKET s, char *errbuf, size_t errbuflen)
137{
138	if (ssl_init_once(is_server, 1, errbuf, errbuflen) < 0) {
139		return NULL;
140	}
141
142	SSL *ssl = SSL_new(ctx); // TODO: also a DTLS context
143	SSL_set_fd(ssl, (int)s);
144
145	if (is_server) {
146		if (SSL_accept(ssl) <= 0) {
147			snprintf(errbuf, errbuflen, "SSL_accept(): %s",
148					ERR_error_string(ERR_get_error(), NULL));
149			return NULL;
150		}
151	} else {
152		if (SSL_connect(ssl) <= 0) {
153			snprintf(errbuf, errbuflen, "SSL_connect(): %s",
154					ERR_error_string(ERR_get_error(), NULL));
155			return NULL;
156		}
157	}
158
159	return ssl;
160}
161
162// Finish using an SSL handle; shut down the connection and free the
163// handle.
164void ssl_finish(SSL *ssl)
165{
166	//
167	// We won't be using this again, so we can just send the
168	// shutdown alert and free up the handle, and have our
169	// caller close the socket.
170	//
171	// XXX - presumably, if the connection is shut down on
172	// our side, either our peer won't have a problem sending
173	// their shutdown alert or will not treat such a problem
174	// as an error.  If this causes errors to be reported,
175	// fix that as appropriate.
176	//
177	SSL_shutdown(ssl);
178	SSL_free(ssl);
179}
180
181// Same return value as sock_send:
182// 0 on OK, -1 on error but closed connection (-2).
183int ssl_send(SSL *ssl, char const *buffer, int size, char *errbuf, size_t errbuflen)
184{
185	int status = SSL_write(ssl, buffer, size);
186	if (status > 0)
187	{
188		// "SSL_write() will only return with success, when the complete contents (...) has been written."
189		return 0;
190	}
191	else
192	{
193		int ssl_err = SSL_get_error(ssl, status); // TODO: does it pop the error?
194		if (ssl_err == SSL_ERROR_ZERO_RETURN)
195		{
196			return -2;
197		}
198		else if (ssl_err == SSL_ERROR_SYSCALL)
199		{
200#ifndef _WIN32
201			if (errno == ECONNRESET || errno == EPIPE) return -2;
202#endif
203		}
204		snprintf(errbuf, errbuflen, "SSL_write(): %s",
205		    ERR_error_string(ERR_get_error(), NULL));
206		return -1;
207	}
208}
209
210// Returns the number of bytes read, or -1 on syserror, or -2 on SSL error.
211int ssl_recv(SSL *ssl, char *buffer, int size, char *errbuf, size_t errbuflen)
212{
213	int status = SSL_read(ssl, buffer, size);
214	if (status <= 0)
215	{
216		int ssl_err = SSL_get_error(ssl, status);
217		if (ssl_err == SSL_ERROR_ZERO_RETURN)
218		{
219			return 0;
220		}
221		else if (ssl_err == SSL_ERROR_SYSCALL)
222		{
223			return -1;
224		}
225		else
226		{
227			// Should not happen
228			snprintf(errbuf, errbuflen, "SSL_read(): %s",
229			    ERR_error_string(ERR_get_error(), NULL));
230			return -2;
231		}
232	}
233	else
234	{
235		return status;
236	}
237}
238
239#endif // HAVE_OPENSSL
240