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
44 static const char *ssl_keyfile = ""; //!< file containing the private key in PEM format
45 static const char *ssl_certfile = ""; //!< file containing the server's certificate in PEM format
46 static 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?
50 static SSL_CTX *ctx;
51
ssl_set_certfile(const char * certfile)52 void ssl_set_certfile(const char *certfile)
53 {
54 ssl_certfile = certfile;
55 }
56
ssl_set_keyfile(const char * keyfile)57 void ssl_set_keyfile(const char *keyfile)
58 {
59 ssl_keyfile = keyfile;
60 }
61
ssl_init_once(int is_server,int enable_compression,char * errbuf,size_t errbuflen)62 int 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
132 die:
133 return -1;
134 }
135
ssl_promotion(int is_server,SOCKET s,char * errbuf,size_t errbuflen)136 SSL *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.
ssl_finish(SSL * ssl)164 void 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).
ssl_send(SSL * ssl,char const * buffer,int size,char * errbuf,size_t errbuflen)183 int 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.
ssl_recv(SSL * ssl,char * buffer,int size,char * errbuf,size_t errbuflen)211 int 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