1 // Copyright (c) 1996-2022 by the citadel.org team
3 // This program is open source software. You can redistribute it and/or
4 // modify it under the terms of the GNU General Public License, version 3.
6 // This program is distributed in the hope that it will be useful,
7 // but WITHOUT ANY WARRANTY; without even the implied warranty of
8 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
9 // GNU General Public License for more details.
18 SSL_CTX *ssl_ctx; // Global SSL context
19 char key_file[PATH_MAX] = "";
20 char cert_file[PATH_MAX] = "";
21 char *ssl_cipher_list = DEFAULT_SSL_CIPHER_LIST;
23 pthread_key_t ThreadSSL; // Per-thread SSL context
26 // Set the private key and certificate chain for the global SSL Context.
27 // This is called during initialization, and can be called again later if the certificate changes.
28 void bind_to_key_and_certificate(void) {
30 SSL_CTX *old_ctx, *new_ctx;
32 if (IsEmptyStr(key_file)) {
33 snprintf(key_file, sizeof key_file, "%s/keys/citadel.key", ctdl_dir);
35 if (IsEmptyStr(cert_file)) {
36 snprintf(cert_file, sizeof key_file, "%s/keys/citadel.cer", ctdl_dir);
39 if (!(new_ctx = SSL_CTX_new(SSLv23_server_method()))) {
40 syslog(LOG_WARNING, "SSL_CTX_new failed: %s", ERR_reason_error_string(ERR_get_error()));
44 syslog(LOG_INFO, "Requesting cipher list: %s", ssl_cipher_list);
45 if (!(SSL_CTX_set_cipher_list(new_ctx, ssl_cipher_list))) {
46 syslog(LOG_WARNING, "SSL_CTX_set_cipher_list failed: %s", ERR_reason_error_string(ERR_get_error()));
50 syslog(LOG_DEBUG, "crypto: [re]installing key \"%s\" and certificate \"%s\"", key_file, cert_file);
52 SSL_CTX_use_certificate_chain_file(new_ctx, cert_file);
53 SSL_CTX_use_PrivateKey_file(new_ctx, key_file, SSL_FILETYPE_PEM);
55 if ( !SSL_CTX_check_private_key(new_ctx) ) {
56 syslog(LOG_WARNING, "crypto: cannot install certificate: %s", ERR_reason_error_string(ERR_get_error()));
62 SSL_CTX_free(old_ctx);
66 // initialize ssl engine, load certs and initialize openssl internals
69 // Initialize the OpenSSL library
70 SSL_load_error_strings();
71 ERR_load_crypto_strings();
72 OpenSSL_add_all_algorithms();
75 // Now try to bind to the key and certificate.
76 bind_to_key_and_certificate();
80 // Check the modification time of the key and certificate -- reload if either one changed
81 void update_key_and_cert_if_needed(void) {
82 static time_t previous_mtime = 0;
86 if (stat(key_file, &keystat) != 0) {
87 syslog(LOG_ERR, "%s: %s", key_file, strerror(errno));
90 if (stat(cert_file, &certstat) != 0) {
91 syslog(LOG_ERR, "%s: %s", cert_file, strerror(errno));
95 if ((keystat.st_mtime + certstat.st_mtime) != previous_mtime) {
96 bind_to_key_and_certificate();
97 previous_mtime = keystat.st_mtime + certstat.st_mtime;
102 // starts SSL/TLS encryption for the current session.
103 int starttls(int sock) {
105 int retval, bits, alg_bits;
107 // Check the modification time of the key and certificate -- reload if they changed
108 update_key_and_cert_if_needed();
110 // SSL is a thread-specific thing, I think.
111 pthread_setspecific(ThreadSSL, NULL);
116 if (!(newssl = SSL_new(ssl_ctx))) {
117 syslog(LOG_WARNING, "SSL_new failed: %s", ERR_reason_error_string(ERR_get_error()));
120 if (!(SSL_set_fd(newssl, sock))) {
121 syslog(LOG_WARNING, "SSL_set_fd failed: %s", ERR_reason_error_string(ERR_get_error()));
125 retval = SSL_accept(newssl);
127 // Can't notify the client of an error here; they will
128 // discover the problem at the SSL layer and should
129 // revert to unencrypted communications.
131 const char *ssl_error_reason = NULL;
133 errval = SSL_get_error(newssl, retval);
134 ssl_error_reason = ERR_reason_error_string(ERR_get_error());
135 if (ssl_error_reason == NULL) {
136 syslog(LOG_WARNING, "first SSL_accept failed: errval=%ld, retval=%d %s", errval, retval, strerror(errval));
139 syslog(LOG_WARNING, "first SSL_accept failed: %s", ssl_error_reason);
143 syslog(LOG_INFO, "SSL_accept success");
145 BIO_set_close(SSL_get_rbio(newssl), BIO_NOCLOSE);
146 bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(newssl), &alg_bits);
147 syslog(LOG_INFO, "SSL/TLS using %s on %s (%d of %d bits)",
148 SSL_CIPHER_get_name(SSL_get_current_cipher(newssl)),
149 SSL_CIPHER_get_version(SSL_get_current_cipher(newssl)),
152 pthread_setspecific(ThreadSSL, newssl);
153 syslog(LOG_INFO, "SSL started");
158 // shuts down the TLS connection
160 // WARNING: This may make your session vulnerable to a known plaintext
161 // attack in the current implmentation.
164 if (THREADSSL == NULL) {
168 syslog(LOG_INFO, "Ending SSL/TLS");
169 SSL_shutdown(THREADSSL);
170 SSL_get_SSL_CTX(THREADSSL);
172 pthread_setspecific(ThreadSSL, NULL);
176 // Send binary data to the client encrypted.
177 int client_write_ssl(const StrBuf *Buf) {
184 if (THREADSSL == NULL) return -1;
186 nbytes = nremain = StrLength(Buf);
189 while (nremain > 0) {
190 if (SSL_want_write(THREADSSL)) {
191 if ((SSL_read(THREADSSL, junk, 0)) < 1) {
192 syslog(LOG_WARNING, "SSL_read in client_write: %s", ERR_reason_error_string(ERR_get_error()));
195 retval = SSL_write(THREADSSL, &buf[nbytes - nremain], nremain);
199 errval = SSL_get_error(THREADSSL, retval);
200 if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
204 syslog(LOG_WARNING, "SSL_write: %s", ERR_reason_error_string(ERR_get_error()));
206 syslog(LOG_WARNING, "errno is %d\n", errno);
217 // read data from the encrypted layer.
218 int client_read_sslbuffer(StrBuf *buf, int timeout) {
219 char sbuf[16384]; // OpenSSL communicates in 16k blocks, so let's speak its native tongue.
222 SSL *pssl = THREADSSL;
224 if (pssl == NULL) return(-1);
227 if (SSL_want_read(pssl)) {
228 if ((SSL_write(pssl, junk, 0)) < 1) {
229 syslog(LOG_WARNING, "SSL_write in client_read");
232 rlen = SSL_read(pssl, sbuf, sizeof(sbuf));
236 errval = SSL_get_error(pssl, rlen);
237 if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
241 syslog(LOG_WARNING, "SSL_read in client_read: %s", ERR_reason_error_string(ERR_get_error()));
245 StrBufAppendBufPlain(buf, sbuf, rlen, 0);
251 #endif /* HAVE_OPENSSL */