X-Git-Url: https://code.citadel.org/?p=citadel.git;a=blobdiff_plain;f=webcit%2Fcrypto.c;fp=webcit%2Fcrypto.c;h=0a91289571e62850dca1d520d02233af6416a3d5;hp=0000000000000000000000000000000000000000;hb=8611acef7ff4213c28ad20ff755d34509870bc96;hpb=76a0f8571de023fe6bd20390174a2302e0a0b982 diff --git a/webcit/crypto.c b/webcit/crypto.c new file mode 100644 index 000000000..0a9128957 --- /dev/null +++ b/webcit/crypto.c @@ -0,0 +1,251 @@ +// Copyright (c) 1996-2022 by the citadel.org team +// +// This program is open source software. You can redistribute it and/or +// modify it under the terms of the GNU General Public License, version 3. +// +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +#include "sysdep.h" +#ifdef HAVE_OPENSSL + +#include "webcit.h" +#include "webserver.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; + +pthread_key_t ThreadSSL; // Per-thread SSL context + + +// 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 (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); + } + + 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; + } + + 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 either one 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. +int starttls(int sock) { + SSL *newssl; + int retval, bits, alg_bits; + + // Check the modification time of the key and certificate -- reload if they changed + update_key_and_cert_if_needed(); + + // SSL is a thread-specific thing, I think. + pthread_setspecific(ThreadSSL, NULL); + + if (!ssl_ctx) { + return(1); + } + if (!(newssl = SSL_new(ssl_ctx))) { + syslog(LOG_WARNING, "SSL_new failed: %s", ERR_reason_error_string(ERR_get_error())); + return(2); + } + if (!(SSL_set_fd(newssl, sock))) { + syslog(LOG_WARNING, "SSL_set_fd failed: %s", ERR_reason_error_string(ERR_get_error())); + SSL_free(newssl); + return(3); + } + retval = SSL_accept(newssl); + 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; + const char *ssl_error_reason = NULL; + + errval = SSL_get_error(newssl, retval); + ssl_error_reason = ERR_reason_error_string(ERR_get_error()); + if (ssl_error_reason == NULL) { + syslog(LOG_WARNING, "first SSL_accept failed: errval=%ld, retval=%d %s", errval, retval, strerror(errval)); + } + else { + syslog(LOG_WARNING, "first SSL_accept failed: %s", ssl_error_reason); + } + } + else { + syslog(LOG_INFO, "SSL_accept success"); + } + BIO_set_close(SSL_get_rbio(newssl), BIO_NOCLOSE); + bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(newssl), &alg_bits); + syslog(LOG_INFO, "SSL/TLS using %s on %s (%d of %d bits)", + SSL_CIPHER_get_name(SSL_get_current_cipher(newssl)), + SSL_CIPHER_get_version(SSL_get_current_cipher(newssl)), + bits, alg_bits); + + pthread_setspecific(ThreadSSL, newssl); + syslog(LOG_INFO, "SSL started"); + return(0); +} + + +// shuts down the TLS connection +// +// WARNING: This may make your session vulnerable to a known plaintext +// attack in the current implmentation. +void endtls(void) { + + if (THREADSSL == NULL) { + return; + } + + syslog(LOG_INFO, "Ending SSL/TLS"); + SSL_shutdown(THREADSSL); + SSL_get_SSL_CTX(THREADSSL); + SSL_free(THREADSSL); + pthread_setspecific(ThreadSSL, NULL); +} + + +// Send binary data to the client encrypted. +int client_write_ssl(const StrBuf *Buf) { + const char *buf; + int retval; + int nremain; + long nbytes; + char junk[1]; + + if (THREADSSL == NULL) return -1; + + nbytes = nremain = StrLength(Buf); + buf = ChrPtr(Buf); + + while (nremain > 0) { + if (SSL_want_write(THREADSSL)) { + if ((SSL_read(THREADSSL, junk, 0)) < 1) { + syslog(LOG_WARNING, "SSL_read in client_write: %s", ERR_reason_error_string(ERR_get_error())); + } + } + retval = SSL_write(THREADSSL, &buf[nbytes - nremain], nremain); + if (retval < 1) { + long errval; + + errval = SSL_get_error(THREADSSL, retval); + if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) { + sleeeeeeeeeep(1); + continue; + } + syslog(LOG_WARNING, "SSL_write: %s", ERR_reason_error_string(ERR_get_error())); + if (retval == -1) { + syslog(LOG_WARNING, "errno is %d\n", errno); + } + endtls(); + return -1; + } + nremain -= retval; + } + return 0; +} + + +// read data from the encrypted layer. +int client_read_sslbuffer(StrBuf *buf, int timeout) { + char sbuf[16384]; // OpenSSL communicates in 16k blocks, so let's speak its native tongue. + int rlen; + char junk[1]; + SSL *pssl = THREADSSL; + + if (pssl == NULL) return(-1); + + while (1) { + if (SSL_want_read(pssl)) { + if ((SSL_write(pssl, junk, 0)) < 1) { + syslog(LOG_WARNING, "SSL_write in client_read"); + } + } + rlen = SSL_read(pssl, sbuf, sizeof(sbuf)); + if (rlen < 1) { + long errval; + + errval = SSL_get_error(pssl, rlen); + if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) { + sleeeeeeeeeep(1); + continue; + } + syslog(LOG_WARNING, "SSL_read in client_read: %s", ERR_reason_error_string(ERR_get_error())); + endtls(); + return (-1); + } + StrBufAppendBufPlain(buf, sbuf, rlen, 0); + return rlen; + } + return (0); +} + +#endif /* HAVE_OPENSSL */