1 // Copyright (c) 1996-2021 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) {
33 if (IsEmptyStr(key_file)) {
34 snprintf(key_file, sizeof key_file, "%s/keys/citadel.key", ctdl_dir);
36 if (IsEmptyStr(cert_file)) {
37 snprintf(cert_file, sizeof key_file, "%s/keys/citadel.cer", ctdl_dir);
40 syslog(LOG_DEBUG, "crypto: [re]installing key \"%s\" and certificate \"%s\"", key_file, cert_file);
42 SSL_CTX_use_certificate_chain_file(ssl_ctx, cert_file);
43 SSL_CTX_use_PrivateKey_file(ssl_ctx, key_file, SSL_FILETYPE_PEM);
45 if ( !SSL_CTX_check_private_key(ssl_ctx) ) {
46 syslog(LOG_WARNING, "crypto: cannot install certificate: %s", ERR_reason_error_string(ERR_get_error()));
51 // initialize ssl engine, load certs and initialize openssl internals
53 const SSL_METHOD *ssl_method;
55 #ifndef OPENSSL_NO_EGD
56 if (!access("/var/run/egd-pool", F_OK)) {
57 RAND_egd("/var/run/egd-pool");
62 syslog(LOG_WARNING, "PRNG not adequately seeded, won't do SSL/TLS");
66 // Initialize SSL transport layer
68 SSL_load_error_strings();
69 ssl_method = SSLv23_server_method();
70 if (!(ssl_ctx = SSL_CTX_new(ssl_method))) {
71 syslog(LOG_WARNING, "SSL_CTX_new failed: %s", ERR_reason_error_string(ERR_get_error()));
75 syslog(LOG_INFO, "Requesting cipher list: %s", ssl_cipher_list);
76 if (!(SSL_CTX_set_cipher_list(ssl_ctx, ssl_cipher_list))) {
77 syslog(LOG_WARNING, "SSL_CTX_set_cipher_list failed: %s", ERR_reason_error_string(ERR_get_error()));
82 // Now try to bind to the key and certificate.
83 bind_to_key_and_certificate();
87 // Check the modification time of the key and certificate -- reload if either one changed
88 void update_key_and_cert_if_needed(void) {
89 static time_t previous_mtime = 0;
93 if (stat(key_file, &keystat) != 0) {
94 syslog(LOG_ERR, "%s: %s", key_file, strerror(errno));
97 if (stat(cert_file, &certstat) != 0) {
98 syslog(LOG_ERR, "%s: %s", cert_file, strerror(errno));
102 if ((keystat.st_mtime + certstat.st_mtime) != previous_mtime) {
103 bind_to_key_and_certificate();
104 previous_mtime = keystat.st_mtime + certstat.st_mtime;
109 // starts SSL/TLS encryption for the current session.
110 int starttls(int sock) {
112 int retval, bits, alg_bits;
114 // Check the modification time of the key and certificate -- reload if they changed
115 update_key_and_cert_if_needed();
117 // SSL is a thread-specific thing, I think.
118 pthread_setspecific(ThreadSSL, NULL);
123 if (!(newssl = SSL_new(ssl_ctx))) {
124 syslog(LOG_WARNING, "SSL_new failed: %s", ERR_reason_error_string(ERR_get_error()));
127 if (!(SSL_set_fd(newssl, sock))) {
128 syslog(LOG_WARNING, "SSL_set_fd failed: %s", ERR_reason_error_string(ERR_get_error()));
132 retval = SSL_accept(newssl);
134 // Can't notify the client of an error here; they will
135 // discover the problem at the SSL layer and should
136 // revert to unencrypted communications.
138 const char *ssl_error_reason = NULL;
140 errval = SSL_get_error(newssl, retval);
141 ssl_error_reason = ERR_reason_error_string(ERR_get_error());
142 if (ssl_error_reason == NULL) {
143 syslog(LOG_WARNING, "first SSL_accept failed: errval=%ld, retval=%d %s", errval, retval, strerror(errval));
146 syslog(LOG_WARNING, "first SSL_accept failed: %s", ssl_error_reason);
149 // retval = SSL_accept(newssl);
153 // const char *ssl_error_reason = NULL;
155 // errval = SSL_get_error(newssl, retval);
156 // ssl_error_reason = ERR_reason_error_string(ERR_get_error());
157 // if (ssl_error_reason == NULL) {
158 // syslog(LOG_WARNING, "second SSL_accept failed: errval=%ld, retval=%d (%s)", errval, retval, strerror(errval));
161 // syslog(LOG_WARNING, "second SSL_accept failed: %s", ssl_error_reason);
168 syslog(LOG_INFO, "SSL_accept success");
170 /*r = */BIO_set_close(SSL_get_rbio(newssl), BIO_NOCLOSE);
171 bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(newssl), &alg_bits);
172 syslog(LOG_INFO, "SSL/TLS using %s on %s (%d of %d bits)",
173 SSL_CIPHER_get_name(SSL_get_current_cipher(newssl)),
174 SSL_CIPHER_get_version(SSL_get_current_cipher(newssl)),
177 pthread_setspecific(ThreadSSL, newssl);
178 syslog(LOG_INFO, "SSL started");
183 // shuts down the TLS connection
185 // WARNING: This may make your session vulnerable to a known plaintext
186 // attack in the current implmentation.
189 if (THREADSSL == NULL) {
193 syslog(LOG_INFO, "Ending SSL/TLS");
194 SSL_shutdown(THREADSSL);
195 SSL_get_SSL_CTX(THREADSSL);
197 pthread_setspecific(ThreadSSL, NULL);
201 // Send binary data to the client encrypted.
202 int client_write_ssl(const StrBuf *Buf) {
209 if (THREADSSL == NULL) return -1;
211 nbytes = nremain = StrLength(Buf);
214 while (nremain > 0) {
215 if (SSL_want_write(THREADSSL)) {
216 if ((SSL_read(THREADSSL, junk, 0)) < 1) {
217 syslog(LOG_WARNING, "SSL_read in client_write: %s", ERR_reason_error_string(ERR_get_error()));
220 retval = SSL_write(THREADSSL, &buf[nbytes - nremain], nremain);
224 errval = SSL_get_error(THREADSSL, retval);
225 if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
229 syslog(LOG_WARNING, "SSL_write: %s", ERR_reason_error_string(ERR_get_error()));
231 syslog(LOG_WARNING, "errno is %d\n", errno);
242 // read data from the encrypted layer.
243 int client_read_sslbuffer(StrBuf *buf, int timeout) {
244 char sbuf[16384]; // OpenSSL communicates in 16k blocks, so let's speak its native tongue.
247 SSL *pssl = THREADSSL;
249 if (pssl == NULL) return(-1);
252 if (SSL_want_read(pssl)) {
253 if ((SSL_write(pssl, junk, 0)) < 1) {
254 syslog(LOG_WARNING, "SSL_write in client_read");
257 rlen = SSL_read(pssl, sbuf, sizeof(sbuf));
261 errval = SSL_get_error(pssl, rlen);
262 if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
266 syslog(LOG_WARNING, "SSL_read in client_read: %s", ERR_reason_error_string(ERR_get_error()));
270 StrBufAppendBufPlain(buf, sbuf, rlen, 0);
276 #endif /* HAVE_OPENSSL */