+/* $Id$ */
+
+#include <unistd.h>
+#include <sys/types.h>
+#include "sysdep.h"
+#ifdef HAVE_OPENSSL
+#include <openssl/ssl.h>
+#include <openssl/err.h>
+#include <openssl/rand.h>
+#endif
+#ifdef HAVE_PTHREAD_H
+#include <pthread.h>
+#endif
+#include "server.h"
+#include "serv_crypto.h"
+#include "sysdep_decls.h"
+#include "dynloader.h"
+
+
+#ifdef HAVE_OPENSSL
+SSL_CTX *ssl_ctx; /* SSL context */
+pthread_mutex_t **SSLCritters; /* Things needing locking */
+
+
+void init_ssl(void)
+{
+ SSL_METHOD *ssl_method;
+ DH *dh;
+
+ if (!RAND_status()) {
+ lprintf(2, "PRNG not adequately seeded, won't do SSL/TLS\n");
+ return;
+ }
+ SSLCritters = mallok(CRYPTO_num_locks() * sizeof (pthread_mutex_t *));
+ if (!SSLCritters) {
+ lprintf(1, "citserver: can't allocate memory!!\n");
+ /* Nothing's been initialized, just die */
+ exit(1);
+ } else {
+ int a;
+
+ for (a=0; a<CRYPTO_num_locks(); a++) {
+ SSLCritters[a] = mallok(sizeof (pthread_mutex_t));
+ if (!SSLCritters[a]) {
+ lprintf(1, "citserver: can't allocate memory!!\n");
+ /* Nothing's been initialized, just die */
+ exit(1);
+ }
+ pthread_mutex_init(SSLCritters[a], NULL);
+ }
+ }
+
+ /*
+ * Initialize SSL transport layer
+ */
+ SSL_library_init();
+ SSL_load_error_strings();
+ ssl_method = SSLv23_server_method();
+ if (!(ssl_ctx = SSL_CTX_new(ssl_method))) {
+ lprintf(2, "SSL_CTX_new failed: %s\n",
+ ERR_reason_error_string(ERR_get_error()));
+ return;
+ }
+ if (!(SSL_CTX_set_cipher_list(ssl_ctx, CIT_CIPHERS))) {
+ lprintf(2, "SSL: No ciphers available\n");
+ SSL_CTX_free(ssl_ctx);
+ ssl_ctx = NULL;
+ return;
+ }
+#if 0
+#if SSLEAY_VERSION_NUMBER >= 0x00906000L
+ SSL_CTX_set_mode(ssl_ctx, SSL_CTX_get_mode(ssl_ctx) |
+ SSL_MODE_AUTO_RETRY);
+#endif
+#endif
+ CRYPTO_set_locking_callback(ssl_lock);
+ CRYPTO_set_id_callback(pthread_self);
+
+ /* Load DH parameters into the context */
+ dh = DH_new();
+ if (!dh) {
+ lprintf(2, "init_ssl() can't allocate a DH object: %s\n",
+ ERR_reason_error_string(ERR_get_error()));
+ SSL_CTX_free(ssl_ctx);
+ ssl_ctx = NULL;
+ return;
+ }
+ if (!(BN_hex2bn(&(dh->p), DH_P))) {
+ lprintf(2, "init_ssl() can't assign DH_P: %s\n",
+ ERR_reason_error_string(ERR_get_error()));
+ SSL_CTX_free(ssl_ctx);
+ ssl_ctx = NULL;
+ return;
+ }
+ if (!(BN_hex2bn(&(dh->g), DH_G))) {
+ lprintf(2, "init_ssl() can't assign DH_G: %s\n",
+ ERR_reason_error_string(ERR_get_error()));
+ SSL_CTX_free(ssl_ctx);
+ ssl_ctx = NULL;
+ return;
+ }
+ dh->length = DH_L;
+ SSL_CTX_set_tmp_dh(ssl_ctx, dh);
+ DH_free(dh);
+
+ /* Finally let the server know we're here */
+ CtdlRegisterProtoHook(cmd_stls, "STLS", "Start SSL/TLS session");
+ CtdlRegisterProtoHook(cmd_gtls, "GTLS", "Get SSL/TLS session status");
+ CtdlRegisterProtoHook(cmd_etls, "ETLS", "End SSL/TLS session");
+ CtdlRegisterSessionHook(endtls_atlogout, EVT_STOP);
+}
+
+
+/*
+ * client_write_ssl() Send binary data to the client encrypted.
+ */
+void client_write_ssl(char *buf, int nbytes)
+{
+ int retval;
+ int nremain;
+ char junk[1];
+
+ nremain = nbytes;
+
+ while (nremain > 0) {
+ if (SSL_want_write(CC->ssl)) {
+ if ((SSL_read(CC->ssl, junk, 0)) < 1) {
+ lprintf(9, "SSL_read in client_write:\n");
+ ERR_print_errors_fp(stderr);
+ }
+ }
+ retval = SSL_write(CC->ssl, &buf[nbytes - nremain], nremain);
+ if (retval < 1) {
+ long errval;
+
+ errval = SSL_get_error(CC->ssl, retval);
+ if (errval == SSL_ERROR_WANT_READ ||
+ errval == SSL_ERROR_WANT_WRITE) {
+ sleep(1);
+ continue;
+ }
+ lprintf(9, "SSL_write got error %ld\n", errval);
+ endtls(1);
+ client_write(&buf[nbytes - nremain], nremain);
+ return;
+ }
+ nremain -= retval;
+ }
+}
+
+
+/*
+ * client_read_ssl() - read data from the encrypted layer.
+ */
+int client_read_ssl(char *buf, int bytes, int timeout)
+{
+ int len,rlen;
+ fd_set rfds;
+ struct timeval tv;
+ int retval;
+ int s;
+ char junk[1];
+
+ len = 0;
+ while(len<bytes) {
+ FD_ZERO(&rfds);
+ s = BIO_get_fd(CC->ssl->rbio, NULL);
+ FD_SET(s, &rfds);
+ tv.tv_sec = timeout;
+ tv.tv_usec = 0;
+
+ retval = select(s+1, &rfds, NULL, NULL, &tv);
+
+ if (FD_ISSET(s, &rfds) == 0) {
+ return(0);
+ }
+
+ if (SSL_want_read(CC->ssl)) {
+ if ((SSL_write(CC->ssl, junk, 0)) < 1) {
+ lprintf(9, "SSL_write in client_read:\n");
+ ERR_print_errors_fp(stderr);
+ }
+ }
+ rlen = SSL_read(CC->ssl, &buf[len], bytes-len);
+ if (rlen<1) {
+ long errval;
+
+ errval = SSL_get_error(CC->ssl, rlen);
+ if (errval == SSL_ERROR_WANT_READ ||
+ errval == SSL_ERROR_WANT_WRITE) {
+ sleep(1);
+ continue;
+ }
+ lprintf(9, "SSL_read got error %ld\n", errval);
+ endtls(1);
+ return (client_read_to(&buf[len], bytes - len, timeout));
+ }
+ len += rlen;
+ }
+ return(1);
+}
+
+
+/*
+ * cmd_stls() starts SSL/TLS encryption for the current session
+ */
+void cmd_stls(char *params)
+{
+ int retval, bits, alg_bits;
+
+ if (!ssl_ctx) {
+ cprintf("%d No SSL_CTX available\n", ERROR);
+ return;
+ }
+ if (!(CC->ssl = SSL_new(ssl_ctx))) {
+ lprintf(2, "SSL_new failed: %s\n",
+ ERR_reason_error_string(ERR_peek_error()));
+ cprintf("%d SSL_new: %s\n", ERROR,
+ ERR_reason_error_string(ERR_get_error()));
+ return;
+ }
+ if (!(SSL_set_fd(CC->ssl, CC->client_socket))) {
+ lprintf(2, "SSL_set_fd failed: %s\n",
+ ERR_reason_error_string(ERR_peek_error()));
+ SSL_free(CC->ssl);
+ CC->ssl = NULL;
+ cprintf("%d SSL_set_fd: %s\n", ERROR,
+ ERR_reason_error_string(ERR_get_error()));
+ return;
+ }
+ cprintf("%d \n", OK);
+ retval = SSL_accept(CC->ssl);
+ if (retval < 1) {
+ /*
+ * Can't notify the client of an error here; they will
+ * discover the problem at the SSL layer and should
+ * revert to unencrypted communications.
+ */
+ long errval;
+
+ errval = SSL_get_error(CC->ssl, retval);
+ lprintf(2, "SSL_accept failed: %s\n",
+ ERR_reason_error_string(ERR_get_error()));
+ SSL_free(CC->ssl);
+ CC->ssl = NULL;
+ return;
+ }
+ BIO_set_close(CC->ssl->rbio, BIO_NOCLOSE);
+ bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl), &alg_bits);
+ lprintf(3, "Session %d using %s on %s (%d of %d bits)\n", CC->cs_pid,
+ SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
+ SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
+ bits, alg_bits);
+ CC->redirect_ssl = 1;
+}
+
+
+/*
+ * cmd_gtls() returns status info about the TLS connection
+ */
+void cmd_gtls(char *params)
+{
+ int bits, alg_bits;
+
+ if (!CC->ssl || !CC->redirect_ssl) {
+ cprintf("%d Session is not encrypted.\n", ERROR);
+ return;
+ }
+ bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl), &alg_bits);
+ cprintf("%d %s|%s|%d|%d\n", OK,
+ SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
+ SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
+ alg_bits, bits);
+}
+
+
+/* Logout function hook */
+void endtls_atlogout(void)
+{
+ endtls(1);
+}
+
+
+/* Command function hook */
+void cmd_etls(char *params)
+{
+ endtls(0);
+}
+
+
+/*
+ * endtls() shuts down the TLS connection
+ * Parameter is NULL for client request, CitContext * for server request
+ *
+ * WARNING: This may make your session vulnerable to a known plaintext
+ * attack in the current implmentation.
+ */
+void endtls(int who)
+{
+ lprintf(7, "Session %d ending SSL/TLS%s\n", CC->cs_pid,
+ (who) ? "" : " at client request");
+
+ if (!who) {
+ if (!CC->ssl) {
+ cprintf("%d Connection is not encrypted.\n", ERROR);
+ return;
+ }
+ cprintf("%d Now stop encryption.\n", OK);
+ } else if (!CC->ssl) {
+ return;
+ }
+
+ SSL_shutdown(CC->ssl);
+ SSL_free(CC->ssl);
+ CC->ssl = NULL;
+ CC->redirect_ssl = 0;
+}
+
+
+/*
+ * ssl_lock() callback for OpenSSL mutex locks
+ */
+void ssl_lock(int mode, int n, const char *file, int line)
+{
+ if (mode & CRYPTO_LOCK)
+ pthread_mutex_lock(SSLCritters[n]);
+ else
+ pthread_mutex_unlock(SSLCritters[n]);
+}
+#endif /* HAVE_OPENSSL */
projects / citadel.git / commitdiff