2 // Functions in this module handle SSL encryption when WebCit is running
5 // Copyright (c) 1996-2022 by the citadel.org team
7 // This program is open source software. It runs great on the
8 // Linux operating system (and probably elsewhere). You can use,
9 // copy, and run it under the terms of the GNU General Public
12 // This program 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.
19 SSL_CTX *ssl_ctx; // global SSL context
20 char key_file[PATH_MAX] = "";
21 char cert_file[PATH_MAX] = "";
22 char *ssl_cipher_list = DEFAULT_SSL_CIPHER_LIST;
25 // Set the private key and certificate chain for the global SSL Context.
26 // This is called during initialization, and can be called again later if the certificate changes.
27 void bind_to_key_and_certificate(void) {
28 if (IsEmptyStr(key_file)) {
29 snprintf(key_file, sizeof key_file, "%s/keys/citadel.key", ctdl_dir);
31 if (IsEmptyStr(cert_file)) {
32 snprintf(cert_file, sizeof key_file, "%s/keys/citadel.cer", ctdl_dir);
35 syslog(LOG_DEBUG, "crypto: [re]installing key \"%s\" and certificate \"%s\"", key_file, cert_file);
37 SSL_CTX_use_certificate_chain_file(ssl_ctx, cert_file);
38 SSL_CTX_use_PrivateKey_file(ssl_ctx, key_file, SSL_FILETYPE_PEM);
40 if ( !SSL_CTX_check_private_key(ssl_ctx) ) {
41 syslog(LOG_WARNING, "crypto: cannot install certificate: %s", ERR_reason_error_string(ERR_get_error()));
46 // Initialize ssl engine, load certs and initialize openssl internals
48 const SSL_METHOD *ssl_method;
53 EVP_PKEY *req_pkey = NULL;
54 X509_NAME *name = NULL;
59 // Initialize SSL transport layer
61 SSL_load_error_strings();
62 ssl_method = SSLv23_server_method();
63 if (!(ssl_ctx = SSL_CTX_new(ssl_method))) {
64 syslog(LOG_WARNING, "SSL_CTX_new failed: %s", ERR_reason_error_string(ERR_get_error()));
68 syslog(LOG_INFO, "Requesting cipher list: %s", ssl_cipher_list);
69 if (!(SSL_CTX_set_cipher_list(ssl_ctx, ssl_cipher_list))) {
70 syslog(LOG_WARNING, "SSL_CTX_set_cipher_list failed: %s", ERR_reason_error_string(ERR_get_error()));
74 // Now try to bind to the key and certificate.
75 bind_to_key_and_certificate();
79 // Check the modification time of the key and certificate -- reload if they changed
80 void update_key_and_cert_if_needed(void) {
81 static time_t cert_mtime = 0;
85 if (stat(key_file, &keystat) != 0) {
86 syslog(LOG_ERR, "%s: %s", key_file, strerror(errno));
89 if (stat(cert_file, &certstat) != 0) {
90 syslog(LOG_ERR, "%s: %s", cert_file, strerror(errno));
94 if ((keystat.st_mtime > cert_mtime) || (certstat.st_mtime > cert_mtime)) {
95 bind_to_key_and_certificate();
96 cert_mtime = certstat.st_mtime;
101 // starts SSL/TLS encryption for the current session.
102 void starttls(struct client_handle *ch) {
103 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 if (!(ch->ssl_handle = SSL_new(ssl_ctx))) {
113 syslog(LOG_WARNING, "SSL_new failed: %s", ERR_reason_error_string(ERR_get_error()));
116 if (!(SSL_set_fd(ch->ssl_handle, ch->sock))) {
117 syslog(LOG_WARNING, "SSL_set_fd failed: %s", ERR_reason_error_string(ERR_get_error()));
118 SSL_free(ch->ssl_handle);
121 retval = SSL_accept(ch->ssl_handle);
123 syslog(LOG_WARNING, "SSL_accept failed: %s", ERR_reason_error_string(ERR_get_error()));
126 syslog(LOG_INFO, "SSL_accept success");
128 bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(ch->ssl_handle), &alg_bits);
129 syslog(LOG_INFO, "SSL/TLS using %s on %s (%d of %d bits)",
130 SSL_CIPHER_get_name(SSL_get_current_cipher(ch->ssl_handle)),
131 SSL_CIPHER_get_version(SSL_get_current_cipher(ch->ssl_handle)), bits, alg_bits);
132 syslog(LOG_INFO, "SSL started");
136 // shuts down the TLS connection
137 void endtls(struct client_handle *ch) {
138 syslog(LOG_INFO, "Ending SSL/TLS");
139 if (ch->ssl_handle != NULL) {
140 SSL_shutdown(ch->ssl_handle);
141 SSL_get_SSL_CTX(ch->ssl_handle);
142 SSL_free(ch->ssl_handle);
144 ch->ssl_handle = NULL;
148 // Send binary data to the client encrypted.
149 int client_write_ssl(struct client_handle *ch, char *buf, int nbytes) {
154 if (ch->ssl_handle == NULL)
158 while (nremain > 0) {
159 if (SSL_want_write(ch->ssl_handle)) {
160 if ((SSL_read(ch->ssl_handle, junk, 0)) < 1) {
161 syslog(LOG_WARNING, "SSL_read in client_write: %s", ERR_reason_error_string(ERR_get_error()));
164 retval = SSL_write(ch->ssl_handle, &buf[nbytes - nremain], nremain);
168 errval = SSL_get_error(ch->ssl_handle, retval);
169 if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
173 syslog(LOG_WARNING, "SSL_write: %s", ERR_reason_error_string(ERR_get_error()));
175 syslog(LOG_WARNING, "errno is %d", errno);
186 // read data from the encrypted layer
187 int client_read_ssl(struct client_handle *ch, char *buf, int nbytes) {
192 if (ch->ssl_handle == NULL)
195 while (bytes_read < nbytes) {
196 if (SSL_want_read(ch->ssl_handle)) {
197 if ((SSL_write(ch->ssl_handle, junk, 0)) < 1) {
198 syslog(LOG_WARNING, "SSL_write in client_read");
201 rlen = SSL_read(ch->ssl_handle, &buf[bytes_read], nbytes - bytes_read);
204 errval = SSL_get_error(ch->ssl_handle, rlen);
205 if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
209 syslog(LOG_WARNING, "SSL_read error %ld", errval);