1 /* SSL support via OpenSSL library.
2 Copyright (C) 2000-2005 Free Software Foundation, Inc.
3 Originally contributed by Christian Fraenkel.
5 This file is part of GNU Wget.
7 GNU Wget is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 GNU Wget is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with Wget; if not, write to the Free Software
19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 In addition, as a special exception, the Free Software Foundation
22 gives permission to link the code of its release of Wget with the
23 OpenSSL project's "OpenSSL" library (or with modified versions of it
24 that use the same license as the "OpenSSL" library), and distribute
25 the linked executables. You must obey the GNU General Public License
26 in all respects for all of the code used other than "OpenSSL". If you
27 modify this file, you may extend this exception to your version of the
28 file, but you are not obligated to do so. If you do not wish to do
29 so, delete this exception statement from your version. */
44 #include <openssl/bio.h>
45 #include <openssl/crypto.h>
46 #include <openssl/x509.h>
47 #include <openssl/ssl.h>
48 #include <openssl/err.h>
49 #include <openssl/pem.h>
50 #include <openssl/rand.h>
62 /* Application-wide SSL context. This is common to all SSL
66 /* Initialize the SSL's PRNG using various methods. */
72 const char *random_file;
75 /* The PRNG has been seeded; no further action is necessary. */
78 /* Seed from a file specified by the user. This will be the file
79 specified with --random-file, $RANDFILE, if set, or ~/.rnd, if it
82 random_file = opt.random_file;
85 /* Get the random file name using RAND_file_name. */
87 random_file = RAND_file_name (namebuf, sizeof (namebuf));
90 if (random_file && *random_file)
91 /* Seed at most 16k (apparently arbitrary value borrowed from
92 curl) from random file. */
93 RAND_load_file (random_file, 16384);
98 /* Get random data from EGD if opt.egd_file was used. */
99 if (opt.egd_file && *opt.egd_file)
100 RAND_egd (opt.egd_file);
106 /* Under Windows, we can try to seed the PRNG using screen content.
107 This may or may not work, depending on whether we'll calling Wget
115 #if 0 /* don't do this by default */
119 /* Still not random enough, presumably because neither /dev/random
120 nor EGD were available. Try to seed OpenSSL's PRNG with libc
121 PRNG. This is cryptographically weak and defeats the purpose
122 of using OpenSSL, which is why it is highly discouraged. */
124 logprintf (LOG_NOTQUIET, _("WARNING: using a weak random seed.\n"));
126 while (RAND_status () == 0 && maxrand-- > 0)
128 unsigned char rnd = random_number (256);
129 RAND_seed (&rnd, sizeof (rnd));
135 /* This function is called for additional (app-specific) verification
136 of the server certificate. We basically confirm the validity as
137 determined by OpenSSL.
139 #### Someone should audit this for correctness and document it
143 verify_cert_callback (int ok, X509_STORE_CTX *ctx)
146 X509 *cert = X509_STORE_CTX_get_current_cert (ctx);
147 X509_NAME_oneline (X509_get_subject_name (cert), buf, sizeof (buf));
148 /* #### Why are we not using the result of the above call? Are we
149 supposed to print it? */
150 DEBUGP (("verify_cert_callback: %s\n", buf));
154 /* Print errors in the OpenSSL error stack. */
159 unsigned long curerr = 0;
160 while ((curerr = ERR_get_error ()) != 0)
161 logprintf (LOG_NOTQUIET, "OpenSSL: %s\n", ERR_error_string (curerr, NULL));
164 /* Convert keyfile type as used by options.h to a type as accepted by
165 SSL_CTX_use_certificate_file and SSL_CTX_use_PrivateKey_file.
167 (options.h intentionally doesn't use values from openssl/ssl.h so
168 it doesn't depend specifically on OpenSSL for SSL functionality.) */
171 key_type_to_ssl_type (enum keyfile_type type)
176 return SSL_FILETYPE_PEM;
178 return SSL_FILETYPE_ASN1;
184 /* Create an SSL Context and set default paths etc. Called the first
185 time an HTTP download is attempted.
187 Returns 0 on success, non-zero otherwise. */
195 /* The SSL has already been initialized. */
198 /* Init the PRNG. If that fails, bail out. */
200 if (RAND_status () != 1)
202 logprintf (LOG_NOTQUIET,
203 _("Could not seed PRNG; consider using --random-file.\n"));
208 SSL_load_error_strings ();
209 SSLeay_add_all_algorithms ();
210 SSLeay_add_ssl_algorithms ();
212 switch (opt.secure_protocol)
214 case secure_protocol_auto:
215 meth = SSLv23_client_method ();
217 case secure_protocol_sslv2:
218 meth = SSLv2_client_method ();
220 case secure_protocol_sslv3:
221 meth = SSLv3_client_method ();
223 case secure_protocol_tlsv1:
224 meth = TLSv1_client_method ();
230 ssl_ctx = SSL_CTX_new (meth);
234 SSL_CTX_set_default_verify_paths (ssl_ctx);
235 SSL_CTX_load_verify_locations (ssl_ctx, opt.ca_cert, opt.ca_directory);
237 /* Specify whether the connect should fail if the verification of
238 the peer fails or if it should go ahead. */
239 SSL_CTX_set_verify (ssl_ctx,
240 opt.check_cert ? SSL_VERIFY_PEER : SSL_VERIFY_NONE,
241 verify_cert_callback);
244 if (SSL_CTX_use_certificate_file (ssl_ctx, opt.cert_file,
245 key_type_to_ssl_type (opt.cert_type))
249 if (SSL_CTX_use_PrivateKey_file (ssl_ctx, opt.private_key,
250 key_type_to_ssl_type (opt.private_key_type))
254 /* Since fd_write unconditionally assumes partial writes (and
255 handles them correctly), allow them in OpenSSL. */
256 SSL_CTX_set_mode (ssl_ctx, SSL_MODE_ENABLE_PARTIAL_WRITE);
262 SSL_CTX_free (ssl_ctx);
268 openssl_read (int fd, char *buf, int bufsize, void *ctx)
271 SSL *ssl = (SSL *) ctx;
273 ret = SSL_read (ssl, buf, bufsize);
275 && SSL_get_error (ssl, ret) == SSL_ERROR_SYSCALL
281 openssl_write (int fd, char *buf, int bufsize, void *ctx)
284 SSL *ssl = (SSL *) ctx;
286 ret = SSL_write (ssl, buf, bufsize);
288 && SSL_get_error (ssl, ret) == SSL_ERROR_SYSCALL
294 openssl_poll (int fd, double timeout, int wait_for, void *ctx)
296 SSL *ssl = (SSL *) ctx;
299 if (SSL_pending (ssl))
301 return select_fd (fd, timeout, wait_for);
305 openssl_peek (int fd, char *buf, int bufsize, void *ctx)
308 SSL *ssl = (SSL *) ctx;
310 ret = SSL_peek (ssl, buf, bufsize);
312 && SSL_get_error (ssl, ret) == SSL_ERROR_SYSCALL
318 openssl_close (int fd, void *ctx)
320 SSL *ssl = (SSL *) ctx;
330 DEBUGP (("Closed %d/SSL 0x%0lx\n", fd, (unsigned long) ssl));
333 /* Sets up a SSL structure and performs the handshake on fd. The
334 resulting SSL structure is registered with the file descriptor FD
335 using fd_register_transport. That way subsequent calls to xread,
336 xwrite, etc., will use the appropriate SSL functions.
338 Returns 1 on success, 0 on failure. */
345 assert (ssl_ctx != NULL);
346 ssl = SSL_new (ssl_ctx);
349 if (!SSL_set_fd (ssl, fd))
351 SSL_set_connect_state (ssl);
352 if (SSL_connect (ssl) <= 0 || ssl->state != SSL_ST_OK)
355 /* Register FD with Wget's transport layer, i.e. arrange that
356 SSL-enabled functions are used for reading, writing, and polling.
357 That way the rest of Wget can keep using fd_read, fd_write, and
358 friends and not care what happens underneath. */
359 fd_register_transport (fd, openssl_read, openssl_write, openssl_poll,
360 openssl_peek, openssl_close, ssl);
361 DEBUGP (("Connected %d to SSL 0x%0*lx\n", fd, 2 * sizeof (void *),
362 (unsigned long) ssl));