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 /* Print errors in the OpenSSL error stack. */
140 unsigned long curerr = 0;
141 while ((curerr = ERR_get_error ()) != 0)
142 logprintf (LOG_NOTQUIET, "OpenSSL: %s\n", ERR_error_string (curerr, NULL));
145 /* Convert keyfile type as used by options.h to a type as accepted by
146 SSL_CTX_use_certificate_file and SSL_CTX_use_PrivateKey_file.
148 (options.h intentionally doesn't use values from openssl/ssl.h so
149 it doesn't depend specifically on OpenSSL for SSL functionality.) */
152 key_type_to_ssl_type (enum keyfile_type type)
157 return SSL_FILETYPE_PEM;
159 return SSL_FILETYPE_ASN1;
165 /* Create an SSL Context and set default paths etc. Called the first
166 time an HTTP download is attempted.
168 Returns 1 on success, 0 otherwise. */
176 /* The SSL has already been initialized. */
179 /* Init the PRNG. If that fails, bail out. */
181 if (RAND_status () != 1)
183 logprintf (LOG_NOTQUIET,
184 _("Could not seed PRNG; consider using --random-file.\n"));
189 SSL_load_error_strings ();
190 SSLeay_add_all_algorithms ();
191 SSLeay_add_ssl_algorithms ();
193 switch (opt.secure_protocol)
195 case secure_protocol_auto:
196 meth = SSLv23_client_method ();
198 case secure_protocol_sslv2:
199 meth = SSLv2_client_method ();
201 case secure_protocol_sslv3:
202 meth = SSLv3_client_method ();
204 case secure_protocol_tlsv1:
205 meth = TLSv1_client_method ();
211 ssl_ctx = SSL_CTX_new (meth);
215 SSL_CTX_set_default_verify_paths (ssl_ctx);
216 SSL_CTX_load_verify_locations (ssl_ctx, opt.ca_cert, opt.ca_directory);
218 /* Specify whether the connect should fail if the verification of
219 the peer fails or if it should go ahead. */
220 SSL_CTX_set_verify (ssl_ctx,
221 opt.check_cert ? SSL_VERIFY_PEER : SSL_VERIFY_NONE, NULL);
224 if (SSL_CTX_use_certificate_file (ssl_ctx, opt.cert_file,
225 key_type_to_ssl_type (opt.cert_type))
229 if (SSL_CTX_use_PrivateKey_file (ssl_ctx, opt.private_key,
230 key_type_to_ssl_type (opt.private_key_type))
234 /* Since fd_write unconditionally assumes partial writes (and
235 handles them correctly), allow them in OpenSSL. */
236 SSL_CTX_set_mode (ssl_ctx, SSL_MODE_ENABLE_PARTIAL_WRITE);
242 SSL_CTX_free (ssl_ctx);
248 openssl_read (int fd, char *buf, int bufsize, void *ctx)
251 SSL *ssl = (SSL *) ctx;
253 ret = SSL_read (ssl, buf, bufsize);
255 && SSL_get_error (ssl, ret) == SSL_ERROR_SYSCALL
261 openssl_write (int fd, char *buf, int bufsize, void *ctx)
264 SSL *ssl = (SSL *) ctx;
266 ret = SSL_write (ssl, buf, bufsize);
268 && SSL_get_error (ssl, ret) == SSL_ERROR_SYSCALL
274 openssl_poll (int fd, double timeout, int wait_for, void *ctx)
276 SSL *ssl = (SSL *) ctx;
279 if (SSL_pending (ssl))
281 return select_fd (fd, timeout, wait_for);
285 openssl_peek (int fd, char *buf, int bufsize, void *ctx)
288 SSL *ssl = (SSL *) ctx;
290 ret = SSL_peek (ssl, buf, bufsize);
292 && SSL_get_error (ssl, ret) == SSL_ERROR_SYSCALL
298 openssl_close (int fd, void *ctx)
300 SSL *ssl = (SSL *) ctx;
310 DEBUGP (("Closed %d/SSL 0x%0lx\n", fd, (unsigned long) ssl));
313 /* Sets up a SSL structure and performs the handshake on fd. The
314 resulting SSL structure is registered with the file descriptor FD
315 using fd_register_transport. That way subsequent calls to xread,
316 xwrite, etc., will use the appropriate SSL functions.
318 Returns 1 on success, 0 on failure. */
325 assert (ssl_ctx != NULL);
326 ssl = SSL_new (ssl_ctx);
329 if (!SSL_set_fd (ssl, fd))
331 SSL_set_connect_state (ssl);
332 if (SSL_connect (ssl) <= 0 || ssl->state != SSL_ST_OK)
335 /* Register FD with Wget's transport layer, i.e. arrange that
336 SSL-enabled functions are used for reading, writing, and polling.
337 That way the rest of Wget can keep using fd_read, fd_write, and
338 friends and not care what happens underneath. */
339 fd_register_transport (fd, openssl_read, openssl_write, openssl_poll,
340 openssl_peek, openssl_close, ssl);
341 DEBUGP (("Connected %d to SSL 0x%0*lx\n", fd, 2 * sizeof (void *),
342 (unsigned long) ssl));
352 /* Check that the identity of the remote host, as presented by its
353 server certificate, corresponds to HOST, which is the host name the
354 user thinks he's connecting to. This assumes that FD has been
355 connected to an SSL context using ssl_connect. Return 1 if the
356 identity checks out, 0 otherwise.
358 If opt.check_cert is 0, this always returns 1, but still warns the
359 user about the mismatches, if any. */
362 ssl_check_server_identity (int fd, const char *host)
369 /* If the user has specified --no-check-cert, we still want to warn
370 him about problems with the server's certificate. */
371 const char *severity = opt.check_cert ? _("ERROR") : _("WARNING");
373 SSL *ssl = (SSL *) fd_transport_context (fd);
374 assert (ssl != NULL);
376 peer = SSL_get_peer_certificate (ssl);
379 logprintf (LOG_NOTQUIET, _("%s: No certificate presented by %s.\n"),
380 severity, escnonprint (host));
385 vresult = SSL_get_verify_result (ssl);
386 if (vresult != X509_V_OK)
388 logprintf (LOG_NOTQUIET,
389 _("%s: Certificate verification error for %s: %s\n"),
390 severity, escnonprint (host),
391 X509_verify_cert_error_string (vresult));
396 /* Check that the common name matches HOST.
398 #### This should use dNSName if available; according to rfc2818:
399 "If a subjectAltName extension of type dNSName is present, that
400 MUST be used as the identity." */
403 X509_NAME_get_text_by_NID (X509_get_subject_name (peer),
404 NID_commonName, peer_CN, sizeof (peer_CN));
405 if (0 != strcasecmp (peer_CN, host))
407 logprintf (LOG_NOTQUIET, _("\
408 %s: certificate common name `%s' doesn't match requested host name `%s'.\n"),
409 severity, escnonprint (peer_CN), escnonprint (host));
414 /* The certificate was found, verified, and matched HOST. */
421 /* Allow --no-check-cert to disable certificate checking. */
422 return opt.check_cert ? retval : 1;