2 * Functions in this module handle SSL encryption when WebCit is running
5 * Copyright (c) 1996-2018 by the citadel.org team
7 * This program is open source software. You can redistribute it and/or
8 * modify it under the terms of the GNU General Public License, version 3.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
18 SSL_CTX *ssl_ctx; /* SSL context */
19 pthread_mutex_t **SSLCritters; /* Things needing locking */
20 char *ssl_cipher_list = DEFAULT_SSL_CIPHER_LIST;
21 void ssl_lock(int mode, int n, const char *file, int line);
25 * OpenSSL wants a callback function to identify the currently running thread.
26 * Since we are a pthreads program, we convert the output of pthread_self() to a long.
28 static unsigned long id_callback(void)
30 return (unsigned long) pthread_self();
35 * OpenSSL wants a callback function to set and clear various types of locks.
36 * Since we are a pthreads program, we use mutexes.
38 void ssl_lock(int mode, int n, const char *file, int line)
40 if (mode & CRYPTO_LOCK) {
41 pthread_mutex_lock(SSLCritters[n]);
44 pthread_mutex_unlock(SSLCritters[n]);
50 * Generate a private key for SSL
52 void generate_key(char *keyfilename)
58 unsigned long e = RSA_F4;
61 if (access(keyfilename, R_OK) == 0) {
65 syslog(LOG_INFO, "crypto: generating RSA key pair");
69 ret = BN_set_word(bne,e);
75 ret = RSA_generate_key_ex(rsa, bits, bne, NULL);
81 fp = fopen(keyfilename, "w");
83 chmod(keyfilename, 0600);
84 if (PEM_write_RSAPrivateKey(fp, /* the file */
87 NULL, /* no passphr */
92 syslog(LOG_ERR, "crypto: cannot write key: %s", ERR_reason_error_string(ERR_get_error()));
106 * Initialize ssl engine, load certs and initialize openssl internals
110 const SSL_METHOD *ssl_method;
112 X509_REQ *req = NULL;
115 EVP_PKEY *req_pkey = NULL;
116 X509_NAME *name = NULL;
121 SSLCritters = malloc(CRYPTO_num_locks() * sizeof(pthread_mutex_t *));
123 syslog(LOG_ERR, "citserver: can't allocate memory!!");
128 for (a = 0; a < CRYPTO_num_locks(); a++) {
129 SSLCritters[a] = malloc(sizeof(pthread_mutex_t));
130 if (!SSLCritters[a]) {
131 syslog(LOG_INFO, "citserver: can't allocate memory!!");
134 pthread_mutex_init(SSLCritters[a], NULL);
139 * Initialize SSL transport layer
142 SSL_load_error_strings();
143 ssl_method = SSLv23_server_method();
144 if (!(ssl_ctx = SSL_CTX_new(ssl_method))) {
145 syslog(LOG_WARNING, "SSL_CTX_new failed: %s", ERR_reason_error_string(ERR_get_error()));
149 syslog(LOG_INFO, "Requesting cipher list: %s", ssl_cipher_list);
150 if (!(SSL_CTX_set_cipher_list(ssl_ctx, ssl_cipher_list))) {
151 syslog(LOG_WARNING, "SSL_CTX_set_cipher_list failed: %s", ERR_reason_error_string(ERR_get_error()));
155 CRYPTO_set_locking_callback(ssl_lock);
156 CRYPTO_set_id_callback(id_callback);
159 * Get our certificates in order.
160 * First, create the key/cert directory if it's not there already...
162 mkdir(CTDL_CRYPTO_DIR, 0700);
165 * If we still don't have a private key, generate one.
167 generate_key(CTDL_KEY_PATH);
170 * If there is no certificate file on disk, we will be generating a self-signed certificate
171 * in the next step. Therefore, if we have neither a CSR nor a certificate, generate
172 * the CSR in this step so that the next step may commence.
174 if ( (access(CTDL_CER_PATH, R_OK) != 0) && (access(CTDL_CSR_PATH, R_OK) != 0) ) {
175 syslog(LOG_INFO, "Generating a certificate signing request.");
178 * Read our key from the file. No, we don't just keep this
179 * in memory from the above key-generation function, because
180 * there is the possibility that the key was already on disk
181 * and we didn't just generate it now.
183 fp = fopen(CTDL_KEY_PATH, "r");
185 rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
191 /* Create a public key from the private key */
192 if (pk=EVP_PKEY_new(), pk != NULL) {
193 EVP_PKEY_assign_RSA(pk, rsa);
194 if (req = X509_REQ_new(), req != NULL) {
196 /* Set the public key */
197 X509_REQ_set_pubkey(req, pk);
198 X509_REQ_set_version(req, 0L);
199 name = X509_REQ_get_subject_name(req);
200 X509_NAME_add_entry_by_txt(
201 name, "O", MBSTRING_ASC,
202 (unsigned char*)"Citadel Server",
205 X509_NAME_add_entry_by_txt(
206 name, "OU", MBSTRING_ASC,
207 (unsigned char*)"Default Certificate PLEASE CHANGE",
210 X509_NAME_add_entry_by_txt(
217 X509_REQ_set_subject_name(req, name);
220 if (!X509_REQ_sign(req, pk, EVP_md5())) {
221 syslog(LOG_WARNING, "X509_REQ_sign(): error");
224 /* Write it to disk. */
225 fp = fopen(CTDL_CSR_PATH, "w");
227 chmod(CTDL_CSR_PATH, 0600);
228 PEM_write_X509_REQ(fp, req);
232 syslog(LOG_WARNING, "Cannot write key: %s", CTDL_CSR_PATH);
245 syslog(LOG_WARNING, "Unable to read private key.");
251 * Generate a self-signed certificate if we don't have one.
253 if (access(CTDL_CER_PATH, R_OK) != 0) {
254 syslog(LOG_INFO, "Generating a self-signed certificate.");
256 /* Same deal as before: always read the key from disk because
257 * it may or may not have just been generated.
259 fp = fopen(CTDL_KEY_PATH, "r");
261 rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
265 /* This also holds true for the CSR. */
270 if (pk=EVP_PKEY_new(), pk != NULL) {
271 EVP_PKEY_assign_RSA(pk, rsa);
274 fp = fopen(CTDL_CSR_PATH, "r");
276 req = PEM_read_X509_REQ(fp, NULL, NULL, NULL);
281 if (cer = X509_new(), cer != NULL) {
283 ASN1_INTEGER_set(X509_get_serialNumber(cer), 0);
284 X509_set_issuer_name(cer, X509_REQ_get_subject_name(req));
285 X509_set_subject_name(cer, X509_REQ_get_subject_name(req));
286 X509_gmtime_adj(X509_get_notBefore(cer), 0);
287 X509_gmtime_adj(X509_get_notAfter(cer),(long)60*60*24*SIGN_DAYS);
289 req_pkey = X509_REQ_get_pubkey(req);
290 X509_set_pubkey(cer, req_pkey);
291 EVP_PKEY_free(req_pkey);
294 if (!X509_sign(cer, pk, EVP_md5())) {
295 syslog(LOG_WARNING, "X509_sign(): error");
298 /* Write it to disk. */
299 fp = fopen(CTDL_CER_PATH, "w");
301 chmod(CTDL_CER_PATH, 0600);
302 PEM_write_X509(fp, cer);
306 syslog(LOG_WARNING, "Cannot write key: %s", CTDL_CER_PATH);
319 * Now try to bind to the key and certificate.
320 * Note that we use SSL_CTX_use_certificate_chain_file() which allows
321 * the certificate file to contain intermediate certificates.
323 SSL_CTX_use_certificate_chain_file(ssl_ctx, CTDL_CER_PATH);
324 SSL_CTX_use_PrivateKey_file(ssl_ctx, CTDL_KEY_PATH, SSL_FILETYPE_PEM);
325 if ( !SSL_CTX_check_private_key(ssl_ctx) ) {
326 syslog(LOG_WARNING, "Cannot install certificate: %s", ERR_reason_error_string(ERR_get_error()));
333 * starts SSL/TLS encryption for the current session.
335 void starttls(struct client_handle *ch) {
336 int retval, bits, alg_bits;
341 if (!(ch->ssl_handle = SSL_new(ssl_ctx))) {
342 syslog(LOG_WARNING, "SSL_new failed: %s", ERR_reason_error_string(ERR_get_error()));
345 if (!(SSL_set_fd(ch->ssl_handle, ch->sock))) {
346 syslog(LOG_WARNING, "SSL_set_fd failed: %s", ERR_reason_error_string(ERR_get_error()));
347 SSL_free(ch->ssl_handle);
350 retval = SSL_accept(ch->ssl_handle);
353 const char *ssl_error_reason = NULL;
355 errval = SSL_get_error(ch->ssl_handle, retval);
356 ssl_error_reason = ERR_reason_error_string(ERR_get_error());
357 if (ssl_error_reason == NULL) {
358 syslog(LOG_WARNING, "SSL_accept failed: errval=%ld, retval=%d %s", errval, retval, strerror(errval));
361 syslog(LOG_WARNING, "SSL_accept failed: %s\n", ssl_error_reason);
364 retval = SSL_accept(ch->ssl_handle);
368 const char *ssl_error_reason = NULL;
370 errval = SSL_get_error(ch->ssl_handle, retval);
371 ssl_error_reason = ERR_reason_error_string(ERR_get_error());
372 if (ssl_error_reason == NULL) {
373 syslog(LOG_WARNING, "SSL_accept failed: errval=%ld, retval=%d (%s)", errval, retval, strerror(errval));
376 syslog(LOG_WARNING, "SSL_accept failed: %s", ssl_error_reason);
378 SSL_free(ch->ssl_handle);
379 ch->ssl_handle = NULL;
383 syslog(LOG_INFO, "SSL_accept success");
385 bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(ch->ssl_handle), &alg_bits);
386 syslog(LOG_INFO, "SSL/TLS using %s on %s (%d of %d bits)",
387 SSL_CIPHER_get_name(SSL_get_current_cipher(ch->ssl_handle)),
388 SSL_CIPHER_get_version(SSL_get_current_cipher(ch->ssl_handle)),
391 syslog(LOG_INFO, "SSL started");
396 * shuts down the TLS connection
398 void endtls(struct client_handle *ch)
400 syslog(LOG_INFO, "Ending SSL/TLS");
401 if (ch->ssl_handle != NULL) {
402 SSL_shutdown(ch->ssl_handle);
403 SSL_get_SSL_CTX(ch->ssl_handle);
404 SSL_free(ch->ssl_handle);
406 ch->ssl_handle = NULL;
411 * Send binary data to the client encrypted.
413 int client_write_ssl(struct client_handle *ch, char *buf, int nbytes)
419 if (ch->ssl_handle == NULL) return(-1);
422 while (nremain > 0) {
423 if (SSL_want_write(ch->ssl_handle)) {
424 if ((SSL_read(ch->ssl_handle, junk, 0)) < 1) {
425 syslog(LOG_WARNING, "SSL_read in client_write: %s", ERR_reason_error_string(ERR_get_error()));
428 retval = SSL_write(ch->ssl_handle, &buf[nbytes - nremain], nremain);
432 errval = SSL_get_error(ch->ssl_handle, retval);
433 if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
437 syslog(LOG_WARNING, "SSL_write got error %ld, ret %d", errval, retval);
439 syslog(LOG_WARNING, "errno is %d", errno);
451 * read data from the encrypted layer.
453 int client_read_ssl(struct client_handle *ch, char *buf, int nbytes)
459 if (ch->ssl_handle == NULL) return(-1);
461 while (bytes_read < nbytes) {
462 if (SSL_want_read(ch->ssl_handle)) {
463 if ((SSL_write(ch->ssl_handle, junk, 0)) < 1) {
464 syslog(LOG_WARNING, "SSL_write in client_read");
467 rlen = SSL_read(ch->ssl_handle, &buf[bytes_read], nbytes-bytes_read);
471 errval = SSL_get_error(ch->ssl_handle, rlen);
472 if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
476 syslog(LOG_WARNING, "SSL_read error %ld", errval);