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.
15 #include "webserver.h"
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
25 void shutdown_ssl(void) {
30 // Set the private key and certificate chain for the global SSL Context.
31 // This is called during initialization, and can be called again later if the certificate changes.
32 void bind_to_key_and_certificate(void) {
34 SSL_CTX *old_ctx, *new_ctx;
36 if (IsEmptyStr(key_file)) {
37 snprintf(key_file, sizeof key_file, "%s/keys/citadel.key", ctdl_dir);
39 if (IsEmptyStr(cert_file)) {
40 snprintf(cert_file, sizeof key_file, "%s/keys/citadel.cer", ctdl_dir);
43 if (!(new_ctx = SSL_CTX_new(SSLv23_server_method()))) {
44 syslog(LOG_WARNING, "SSL_CTX_new failed: %s", ERR_reason_error_string(ERR_get_error()));
48 syslog(LOG_INFO, "Requesting cipher list: %s", ssl_cipher_list);
49 if (!(SSL_CTX_set_cipher_list(new_ctx, ssl_cipher_list))) {
50 syslog(LOG_WARNING, "SSL_CTX_set_cipher_list failed: %s", ERR_reason_error_string(ERR_get_error()));
54 syslog(LOG_DEBUG, "crypto: [re]installing key \"%s\" and certificate \"%s\"", key_file, cert_file);
56 SSL_CTX_use_certificate_chain_file(new_ctx, cert_file);
57 SSL_CTX_use_PrivateKey_file(new_ctx, key_file, SSL_FILETYPE_PEM);
59 if ( !SSL_CTX_check_private_key(new_ctx) ) {
60 syslog(LOG_WARNING, "crypto: cannot install certificate: %s", ERR_reason_error_string(ERR_get_error()));
66 SSL_CTX_free(old_ctx);
70 // initialize ssl engine, load certs and initialize openssl internals
73 // Initialize SSL transport layer
75 SSL_load_error_strings();
77 // Now try to bind to the key and certificate.
78 bind_to_key_and_certificate();
82 // Check the modification time of the key and certificate -- reload if either one changed
83 void update_key_and_cert_if_needed(void) {
84 static time_t previous_mtime = 0;
88 if (stat(key_file, &keystat) != 0) {
89 syslog(LOG_ERR, "%s: %s", key_file, strerror(errno));
92 if (stat(cert_file, &certstat) != 0) {
93 syslog(LOG_ERR, "%s: %s", cert_file, strerror(errno));
97 if ((keystat.st_mtime + certstat.st_mtime) != previous_mtime) {
98 bind_to_key_and_certificate();
99 previous_mtime = keystat.st_mtime + certstat.st_mtime;
104 // starts SSL/TLS encryption for the current session.
105 int starttls(int sock) {
107 int retval, bits, alg_bits;
109 // Check the modification time of the key and certificate -- reload if they changed
110 update_key_and_cert_if_needed();
112 // SSL is a thread-specific thing, I think.
113 pthread_setspecific(ThreadSSL, NULL);
118 if (!(newssl = SSL_new(ssl_ctx))) {
119 syslog(LOG_WARNING, "SSL_new failed: %s", ERR_reason_error_string(ERR_get_error()));
122 if (!(SSL_set_fd(newssl, sock))) {
123 syslog(LOG_WARNING, "SSL_set_fd failed: %s", ERR_reason_error_string(ERR_get_error()));
127 retval = SSL_accept(newssl);
129 // Can't notify the client of an error here; they will
130 // discover the problem at the SSL layer and should
131 // revert to unencrypted communications.
133 const char *ssl_error_reason = NULL;
135 errval = SSL_get_error(newssl, retval);
136 ssl_error_reason = ERR_reason_error_string(ERR_get_error());
137 if (ssl_error_reason == NULL) {
138 syslog(LOG_WARNING, "first SSL_accept failed: errval=%ld, retval=%d %s", errval, retval, strerror(errval));
141 syslog(LOG_WARNING, "first SSL_accept failed: %s", ssl_error_reason);
145 syslog(LOG_INFO, "SSL_accept success");
147 BIO_set_close(SSL_get_rbio(newssl), BIO_NOCLOSE);
148 bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(newssl), &alg_bits);
149 syslog(LOG_INFO, "SSL/TLS using %s on %s (%d of %d bits)",
150 SSL_CIPHER_get_name(SSL_get_current_cipher(newssl)),
151 SSL_CIPHER_get_version(SSL_get_current_cipher(newssl)),
154 pthread_setspecific(ThreadSSL, newssl);
155 syslog(LOG_INFO, "SSL started");
160 // shuts down the TLS connection
162 // WARNING: This may make your session vulnerable to a known plaintext
163 // attack in the current implmentation.
166 if (THREADSSL == NULL) {
170 syslog(LOG_INFO, "Ending SSL/TLS");
171 SSL_shutdown(THREADSSL);
172 SSL_get_SSL_CTX(THREADSSL);
174 pthread_setspecific(ThreadSSL, NULL);
178 // Send binary data to the client encrypted.
179 int client_write_ssl(const StrBuf *Buf) {
186 if (THREADSSL == NULL) return -1;
188 nbytes = nremain = StrLength(Buf);
191 while (nremain > 0) {
192 if (SSL_want_write(THREADSSL)) {
193 if ((SSL_read(THREADSSL, junk, 0)) < 1) {
194 syslog(LOG_WARNING, "SSL_read in client_write: %s", ERR_reason_error_string(ERR_get_error()));
197 retval = SSL_write(THREADSSL, &buf[nbytes - nremain], nremain);
201 errval = SSL_get_error(THREADSSL, retval);
202 if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
206 syslog(LOG_WARNING, "SSL_write: %s", ERR_reason_error_string(ERR_get_error()));
208 syslog(LOG_WARNING, "errno is %d\n", errno);
219 // read data from the encrypted layer.
220 int client_read_sslbuffer(StrBuf *buf, int timeout) {
221 char sbuf[16384]; // OpenSSL communicates in 16k blocks, so let's speak its native tongue.
224 SSL *pssl = THREADSSL;
226 if (pssl == NULL) return(-1);
229 if (SSL_want_read(pssl)) {
230 if ((SSL_write(pssl, junk, 0)) < 1) {
231 syslog(LOG_WARNING, "SSL_write in client_read");
234 rlen = SSL_read(pssl, sbuf, sizeof(sbuf));
238 errval = SSL_get_error(pssl, rlen);
239 if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
243 syslog(LOG_WARNING, "SSL_read in client_read: %s", ERR_reason_error_string(ERR_get_error()));
247 StrBufAppendBufPlain(buf, sbuf, rlen, 0);
253 #endif /* HAVE_OPENSSL */