--- /dev/null
+// Functions in this module handle SSL encryption when WebCit is running
+// as an HTTPS server.
+//
+// Copyright (c) 1996-2022 by the citadel.org team
+//
+// This program is open source software. Use, duplication, or
+// disclosure are subject to the GNU General Public License v3.
+
+#include "webcit.h"
+
+SSL_CTX *ssl_ctx; // global SSL context
+char key_file[PATH_MAX] = "";
+char cert_file[PATH_MAX] = "";
+char *ssl_cipher_list = DEFAULT_SSL_CIPHER_LIST;
+
+
+// Set the private key and certificate chain for the global SSL Context.
+// This is called during initialization, and can be called again later if the certificate changes.
+void bind_to_key_and_certificate(void) {
+ SSL_CTX *old_ctx, *new_ctx;
+
+ if (!(new_ctx = SSL_CTX_new(SSLv23_server_method()))) {
+ syslog(LOG_WARNING, "SSL_CTX_new failed: %s", ERR_reason_error_string(ERR_get_error()));
+ return;
+ }
+
+ syslog(LOG_INFO, "Requesting cipher list: %s", ssl_cipher_list);
+ if (!(SSL_CTX_set_cipher_list(new_ctx, ssl_cipher_list))) {
+ syslog(LOG_WARNING, "SSL_CTX_set_cipher_list failed: %s", ERR_reason_error_string(ERR_get_error()));
+ return;
+ }
+
+ if (IsEmptyStr(key_file)) {
+ snprintf(key_file, sizeof key_file, "%s/keys/citadel.key", ctdl_dir);
+ }
+ if (IsEmptyStr(cert_file)) {
+ snprintf(cert_file, sizeof key_file, "%s/keys/citadel.cer", ctdl_dir);
+ }
+
+ syslog(LOG_DEBUG, "crypto: [re]installing key \"%s\" and certificate \"%s\"", key_file, cert_file);
+
+ SSL_CTX_use_certificate_chain_file(new_ctx, cert_file);
+ SSL_CTX_use_PrivateKey_file(new_ctx, key_file, SSL_FILETYPE_PEM);
+
+ if ( !SSL_CTX_check_private_key(new_ctx) ) {
+ syslog(LOG_WARNING, "crypto: cannot install certificate: %s", ERR_reason_error_string(ERR_get_error()));
+ }
+
+ old_ctx = ssl_ctx;
+ ssl_ctx = new_ctx;
+ sleep(1);
+ SSL_CTX_free(old_ctx);
+}
+
+
+// Initialize ssl engine, load certs and initialize openssl internals
+void init_ssl(void) {
+
+ // Initialize the OpenSSL library
+ SSL_load_error_strings();
+ ERR_load_crypto_strings();
+ OpenSSL_add_all_algorithms();
+ SSL_library_init();
+
+ // Now try to bind to the key and certificate.
+ bind_to_key_and_certificate();
+}
+
+
+// Check the modification time of the key and certificate -- reload if they changed
+void update_key_and_cert_if_needed(void) {
+ static time_t previous_mtime = 0;
+ struct stat keystat;
+ struct stat certstat;
+
+ if (stat(key_file, &keystat) != 0) {
+ syslog(LOG_ERR, "%s: %s", key_file, strerror(errno));
+ return;
+ }
+ if (stat(cert_file, &certstat) != 0) {
+ syslog(LOG_ERR, "%s: %s", cert_file, strerror(errno));
+ return;
+ }
+
+ if ((keystat.st_mtime + certstat.st_mtime) != previous_mtime) {
+ bind_to_key_and_certificate();
+ previous_mtime = keystat.st_mtime + certstat.st_mtime;
+ }
+}
+
+
+// starts SSL/TLS encryption for the current session.
+void starttls(struct client_handle *ch) {
+ int retval, bits, alg_bits;
+
+ if (!ssl_ctx) {
+ return;
+ }
+
+ // Check the modification time of the key and certificate -- reload if they changed
+ update_key_and_cert_if_needed();
+
+ if (!(ch->ssl_handle = SSL_new(ssl_ctx))) {
+ syslog(LOG_WARNING, "SSL_new failed: %s", ERR_reason_error_string(ERR_get_error()));
+ return;
+ }
+ if (!(SSL_set_fd(ch->ssl_handle, ch->sock))) {
+ syslog(LOG_WARNING, "SSL_set_fd failed: %s", ERR_reason_error_string(ERR_get_error()));
+ SSL_free(ch->ssl_handle);
+ return;
+ }
+ retval = SSL_accept(ch->ssl_handle);
+ if (retval < 1) {
+ syslog(LOG_WARNING, "SSL_accept failed: %s", ERR_reason_error_string(ERR_get_error()));
+ }
+ else {
+ syslog(LOG_INFO, "SSL_accept success");
+ }
+ bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(ch->ssl_handle), &alg_bits);
+ syslog(LOG_INFO, "SSL/TLS using %s on %s (%d of %d bits)",
+ SSL_CIPHER_get_name(SSL_get_current_cipher(ch->ssl_handle)),
+ SSL_CIPHER_get_version(SSL_get_current_cipher(ch->ssl_handle)), bits, alg_bits);
+ syslog(LOG_INFO, "SSL started");
+}
+
+
+// shuts down the TLS connection
+void endtls(struct client_handle *ch) {
+ syslog(LOG_INFO, "Ending SSL/TLS");
+ if (ch->ssl_handle != NULL) {
+ SSL_shutdown(ch->ssl_handle);
+ SSL_get_SSL_CTX(ch->ssl_handle);
+ SSL_free(ch->ssl_handle);
+ }
+ ch->ssl_handle = NULL;
+}
+
+
+// Send binary data to the client encrypted.
+int client_write_ssl(struct client_handle *ch, char *buf, int nbytes) {
+ int retval;
+ int nremain;
+ char junk[1];
+
+ if (ch->ssl_handle == NULL)
+ return (-1);
+
+ nremain = nbytes;
+ while (nremain > 0) {
+ if (SSL_want_write(ch->ssl_handle)) {
+ if ((SSL_read(ch->ssl_handle, junk, 0)) < 1) {
+ syslog(LOG_WARNING, "SSL_read in client_write: %s", ERR_reason_error_string(ERR_get_error()));
+ }
+ }
+ retval = SSL_write(ch->ssl_handle, &buf[nbytes - nremain], nremain);
+ if (retval < 1) {
+ long errval;
+
+ errval = SSL_get_error(ch->ssl_handle, retval);
+ if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
+ sleep(1);
+ continue;
+ }
+ syslog(LOG_WARNING, "SSL_write: %s", ERR_reason_error_string(ERR_get_error()));
+ if (retval == -1) {
+ syslog(LOG_WARNING, "errno is %d", errno);
+ endtls(ch);
+ }
+ return -1;
+ }
+ nremain -= retval;
+ }
+ return 0;
+}
+
+
+// read data from the encrypted layer
+int client_read_ssl(struct client_handle *ch, char *buf, int nbytes) {
+ int bytes_read = 0;
+ int rlen = 0;
+ char junk[1];
+
+ if (ch->ssl_handle == NULL)
+ return (-1);
+
+ while (bytes_read < nbytes) {
+ if (SSL_want_read(ch->ssl_handle)) {
+ if ((SSL_write(ch->ssl_handle, junk, 0)) < 1) {
+ syslog(LOG_WARNING, "SSL_write in client_read");
+ }
+ }
+ rlen = SSL_read(ch->ssl_handle, &buf[bytes_read], nbytes - bytes_read);
+ if (rlen < 1) {
+ long errval;
+ errval = SSL_get_error(ch->ssl_handle, rlen);
+ if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
+ sleep(1);
+ continue;
+ }
+ syslog(LOG_WARNING, "SSL_read error %ld", errval);
+ endtls(ch);
+ return (-1);
+ }
+ bytes_read += rlen;
+ }
+ return (bytes_read);
+}
projects / citadel.git / blobdiff