2019-05-20 15:45:18 +03:00

598 lines
16 KiB
C++

/*
* Copyright (c) 2016 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
*
* Change Date: 2022-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
/**
* @file ssl.c - SSL generic functions
*
* SSL is intended to be available in conjunction with a variety of protocols
* on either the client or server side.
*
* @verbatim
* Revision History
*
* Date Who Description
* 02/02/16 Martin Brampton Initial implementation
*
* @endverbatim
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <sys/ioctl.h>
#include <maxscale/dcb.hh>
#include <maxscale/poll.hh>
#include <maxscale/service.hh>
static RSA* rsa_512 = NULL;
static RSA* rsa_1024 = NULL;
static RSA* tmp_rsa_callback(SSL* s, int is_export, int keylength);
/**
* @brief Check client's SSL capability and start SSL if appropriate.
*
* The protocol should determine whether the client is SSL capable and pass
* the result as the second parameter. If the listener requires SSL but the
* client is not SSL capable, an error message is recorded and failure return
* given. If both sides want SSL, and SSL is not already established, the
* process is triggered by calling dcb_accept_SSL.
*
* @param dcb Request handler DCB connected to the client
* @param is_capable Indicates if the client can handle SSL
* @return 0 if ok, >0 if a problem - see return codes defined in ssl.h
*/
int ssl_authenticate_client(DCB* dcb, bool is_capable)
{
const char* user = dcb->user ? dcb->user : "";
const char* remote = dcb->remote ? dcb->remote : "";
const char* service = (dcb->service && dcb->service->name()) ? dcb->service->name() : "";
if (NULL == dcb->session->listener || NULL == dcb->session->listener->ssl())
{
/* Not an SSL connection on account of listener configuration */
return SSL_AUTH_CHECKS_OK;
}
/* Now we require an SSL connection */
if (!is_capable)
{
/* Should be SSL, but client is not SSL capable */
MXS_INFO("User %s@%s connected to service '%s' without SSL when SSL was required.",
user,
remote,
service);
return SSL_ERROR_CLIENT_NOT_SSL;
}
/* Now we know SSL is required and client is capable */
if (dcb->ssl_state != SSL_HANDSHAKE_DONE && dcb->ssl_state != SSL_ESTABLISHED)
{
int return_code;
/** Do the SSL Handshake */
if (SSL_HANDSHAKE_UNKNOWN == dcb->ssl_state)
{
dcb->ssl_state = SSL_HANDSHAKE_REQUIRED;
}
/**
* Note that this will often fail to achieve its result, because further
* reading (or possibly writing) of SSL related information is needed.
* When that happens, there is a call in poll.c so that an EPOLLIN
* event that arrives while the SSL state is SSL_HANDSHAKE_REQUIRED
* will trigger dcb_accept_SSL. This situation does not result in a
* negative return code - that indicates a real failure.
*/
return_code = dcb_accept_SSL(dcb);
if (return_code < 0)
{
MXS_INFO("User %s@%s failed to connect to service '%s' with SSL.",
user,
remote,
service);
return SSL_ERROR_ACCEPT_FAILED;
}
else if (mxs_log_is_priority_enabled(LOG_INFO))
{
if (1 == return_code)
{
MXS_INFO("User %s@%s connected to service '%s' with SSL.",
user,
remote,
service);
}
else
{
MXS_INFO("User %s@%s connect to service '%s' with SSL in progress.",
user,
remote,
service);
}
}
}
return SSL_AUTH_CHECKS_OK;
}
/**
* @brief If an SSL connection is required, check that it has been established.
*
* This is called at the end of the authentication of a new connection.
* If the result is not true, the data packet is abandoned with further
* data expected from the client.
*
* @param dcb Request handler DCB connected to the client
* @return Boolean to indicate whether connection is healthy
*/
bool ssl_is_connection_healthy(DCB* dcb)
{
/**
* If SSL was never expected, or if the connection has state SSL_ESTABLISHED
* then everything is as we wish. Otherwise, either there is a problem or
* more to be done.
*/
return NULL == dcb->session->listener
|| NULL == dcb->session->listener->ssl()
|| dcb->ssl_state == SSL_ESTABLISHED;
}
/* Looks to be redundant - can remove include for ioctl too */
bool ssl_check_data_to_process(DCB* dcb)
{
/** SSL authentication is still going on, we need to call dcb_accept_SSL
* until it return 1 for success or -1 for error */
if (dcb->ssl_state == SSL_HANDSHAKE_REQUIRED && 1 == dcb_accept_SSL(dcb))
{
int b = 0;
ioctl(dcb->fd, FIONREAD, &b);
if (b != 0)
{
return true;
}
else
{
MXS_DEBUG("[gw_read_client_event] No data in socket after SSL auth");
}
}
return false;
}
/**
* @brief Check whether a DCB requires SSL.
*
* This is a very simple test, but is placed in an SSL function so that
* the knowledge of the SSL process is removed from the more general
* handling of a connection in the protocols.
*
* @param dcb Request handler DCB connected to the client
* @return Boolean indicating whether SSL is required.
*/
bool ssl_required_by_dcb(DCB* dcb)
{
return NULL != dcb->session->listener && NULL != dcb->session->listener->ssl();
}
/**
* @brief Check whether a DCB requires SSL, but SSL is not yet negotiated.
*
* This is a very simple test, but is placed in an SSL function so that
* the knowledge of the SSL process is removed from the more general
* handling of a connection in the protocols.
*
* @param dcb Request handler DCB connected to the client
* @return Boolean indicating whether SSL is required and not negotiated.
*/
bool ssl_required_but_not_negotiated(DCB* dcb)
{
return NULL != dcb->session->listener
&& NULL != dcb->session->listener->ssl()
&& SSL_HANDSHAKE_UNKNOWN == dcb->ssl_state;
}
/**
* Returns an enum ssl_method_type value as string.
*
* @param method A method type.
* @return The method type expressed as a string.
*/
const char* ssl_method_type_to_string(ssl_method_type_t method_type)
{
switch (method_type)
{
#ifndef OPENSSL_1_1
case SERVICE_TLS10:
return "TLSV10";
#endif
#ifdef OPENSSL_1_0
case SERVICE_TLS11:
return "TLSV11";
case SERVICE_TLS12:
return "TLSV12";
#endif
case SERVICE_SSL_MAX:
case SERVICE_TLS_MAX:
case SERVICE_SSL_TLS_MAX:
return "MAX";
default:
return "Unknown";
}
}
ssl_method_type_t string_to_ssl_method_type(const char* str)
{
if (strcasecmp("MAX", str) == 0)
{
return SERVICE_SSL_TLS_MAX;
}
#ifndef OPENSSL_1_1
else if (strcasecmp("TLSV10", str) == 0)
{
return SERVICE_TLS10;
}
#endif
#ifdef OPENSSL_1_0
else if (strcasecmp("TLSV11", str) == 0)
{
return SERVICE_TLS11;
}
else if (strcasecmp("TLSV12", str) == 0)
{
return SERVICE_TLS12;
}
#endif
return SERVICE_SSL_UNKNOWN;
}
void write_ssl_config(int fd, mxs::SSLContext* ssl)
{
if (ssl)
{
dprintf(fd, "ssl=required\n");
if (ssl->ssl_cert)
{
dprintf(fd, "ssl_cert=%s\n", ssl->ssl_cert);
}
if (ssl->ssl_key)
{
dprintf(fd, "ssl_key=%s\n", ssl->ssl_key);
}
if (ssl->ssl_ca_cert)
{
dprintf(fd, "ssl_ca_cert=%s\n", ssl->ssl_ca_cert);
}
if (ssl->ssl_cert_verify_depth)
{
dprintf(fd, "ssl_cert_verify_depth=%d\n", ssl->ssl_cert_verify_depth);
}
dprintf(fd,
"ssl_verify_peer_certificate=%s\n",
ssl->ssl_verify_peer_certificate ? "true" : "false");
const char* version = ssl_method_type_to_string(ssl->ssl_method_type);
dprintf(fd, "ssl_version=%s\n", version);
}
}
int ssl_authenticate_check_status(DCB* dcb)
{
int rval = MXS_AUTH_FAILED;
/**
* We record the SSL status before and after ssl authentication. This allows
* us to detect if the SSL handshake is immediately completed, which means more
* data needs to be read from the socket.
*/
bool health_before = ssl_is_connection_healthy(dcb);
int ssl_ret = ssl_authenticate_client(dcb, dcb->authfunc.connectssl(dcb));
bool health_after = ssl_is_connection_healthy(dcb);
if (ssl_ret != 0)
{
rval = (ssl_ret == SSL_ERROR_CLIENT_NOT_SSL) ? MXS_AUTH_FAILED_SSL : MXS_AUTH_FAILED;
}
else if (!health_after)
{
rval = MXS_AUTH_SSL_INCOMPLETE;
}
else if (!health_before && health_after)
{
rval = MXS_AUTH_SSL_INCOMPLETE;
poll_add_epollin_event_to_dcb(dcb, NULL);
}
else if (health_before && health_after)
{
rval = MXS_AUTH_SSL_COMPLETE;
}
return rval;
}
int listener_set_ssl_version(mxs::SSLContext* ssl_listener, const char* version)
{
if (strcasecmp(version, "MAX") == 0)
{
ssl_listener->ssl_method_type = SERVICE_SSL_TLS_MAX;
}
#ifndef OPENSSL_1_1
else if (strcasecmp(version, "TLSV10") == 0)
{
ssl_listener->ssl_method_type = SERVICE_TLS10;
}
#else
#endif
#ifdef OPENSSL_1_0
else if (strcasecmp(version, "TLSV11") == 0)
{
ssl_listener->ssl_method_type = SERVICE_TLS11;
}
else if (strcasecmp(version, "TLSV12") == 0)
{
ssl_listener->ssl_method_type = SERVICE_TLS12;
}
#endif
else
{
return -1;
}
return 0;
}
void listener_set_certificates(mxs::SSLContext* ssl_listener, const std::string& cert,
const std::string& key, const std::string& ca_cert)
{
MXS_FREE(ssl_listener->ssl_cert);
ssl_listener->ssl_cert = !cert.empty() ? MXS_STRDUP_A(cert.c_str()) : nullptr;
MXS_FREE(ssl_listener->ssl_key);
ssl_listener->ssl_key = !key.empty() ? MXS_STRDUP_A(key.c_str()) : nullptr;
MXS_FREE(ssl_listener->ssl_ca_cert);
ssl_listener->ssl_ca_cert = !ca_cert.empty() ? MXS_STRDUP_A(ca_cert.c_str()) : nullptr;
}
RSA* create_rsa(int bits)
{
#ifdef OPENSSL_1_1
BIGNUM* bn = BN_new();
BN_set_word(bn, RSA_F4);
RSA* rsa = RSA_new();
RSA_generate_key_ex(rsa, bits, bn, NULL);
BN_free(bn);
return rsa;
#else
return RSA_generate_key(bits, RSA_F4, NULL, NULL);
#endif
}
// thread-local non-POD types are not supported with older versions of GCC
static thread_local std::string* ssl_errbuf;
static const char* get_ssl_errors()
{
if (ssl_errbuf == NULL)
{
ssl_errbuf = new std::string;
}
char errbuf[200]; // Enough space according to OpenSSL documentation
ssl_errbuf->clear();
for (int err = ERR_get_error(); err; err = ERR_get_error())
{
if (!ssl_errbuf->empty())
{
ssl_errbuf->append(", ");
}
ssl_errbuf->append(ERR_error_string(err, errbuf));
}
return ssl_errbuf->c_str();
}
/**
* The RSA key generation callback function for OpenSSL.
* @param s SSL structure
* @param is_export Not used
* @param keylength Length of the key
* @return Pointer to RSA structure
*/
static RSA* tmp_rsa_callback(SSL* s, int is_export, int keylength)
{
RSA* rsa_tmp = NULL;
switch (keylength)
{
case 512:
if (rsa_512)
{
rsa_tmp = rsa_512;
}
else
{
/* generate on the fly, should not happen in this example */
rsa_tmp = create_rsa(keylength);
rsa_512 = rsa_tmp; /* Remember for later reuse */
}
break;
case 1024:
if (rsa_1024)
{
rsa_tmp = rsa_1024;
}
break;
default:
/* Generating a key on the fly is very costly, so use what is there */
if (rsa_1024)
{
rsa_tmp = rsa_1024;
}
else
{
rsa_tmp = rsa_512; /* Use at least a shorter key */
}
}
return rsa_tmp;
}
bool SSL_LISTENER_init(mxs::SSLContext* ssl)
{
mxb_assert(!ssl->ssl_init_done);
bool rval = true;
switch (ssl->ssl_method_type)
{
#ifndef OPENSSL_1_1
case SERVICE_TLS10:
ssl->method = (SSL_METHOD*)TLSv1_method();
break;
#endif
#ifdef OPENSSL_1_0
case SERVICE_TLS11:
ssl->method = (SSL_METHOD*)TLSv1_1_method();
break;
case SERVICE_TLS12:
ssl->method = (SSL_METHOD*)TLSv1_2_method();
break;
#endif
/** Rest of these use the maximum available SSL/TLS methods */
case SERVICE_SSL_MAX:
ssl->method = (SSL_METHOD*)SSLv23_method();
break;
case SERVICE_TLS_MAX:
ssl->method = (SSL_METHOD*)SSLv23_method();
break;
case SERVICE_SSL_TLS_MAX:
ssl->method = (SSL_METHOD*)SSLv23_method();
break;
default:
ssl->method = (SSL_METHOD*)SSLv23_method();
break;
}
SSL_CTX* ctx = SSL_CTX_new(ssl->method);
if (ctx == NULL)
{
MXS_ERROR("SSL context initialization failed: %s", get_ssl_errors());
return false;
}
SSL_CTX_set_default_read_ahead(ctx, 0);
/** Enable all OpenSSL bug fixes */
SSL_CTX_set_options(ctx, SSL_OP_ALL);
/** Disable SSLv3 */
SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv3);
// Disable session cache
SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_OFF);
//
// Note: This is not safe if SSL initialization is done concurrently
//
/** Generate the 512-bit and 1024-bit RSA keys */
if (rsa_512 == NULL && (rsa_512 = create_rsa(512)) == NULL)
{
MXS_ERROR("512-bit RSA key generation failed.");
rval = false;
}
else if (rsa_1024 == NULL && (rsa_1024 = create_rsa(1024)) == NULL)
{
MXS_ERROR("1024-bit RSA key generation failed.");
rval = false;
}
else
{
mxb_assert(rsa_512 && rsa_1024);
SSL_CTX_set_tmp_rsa_callback(ctx, tmp_rsa_callback);
}
mxb_assert(ssl->ssl_ca_cert);
/* Load the CA certificate into the SSL_CTX structure */
if (!SSL_CTX_load_verify_locations(ctx, ssl->ssl_ca_cert, NULL))
{
MXS_ERROR("Failed to set Certificate Authority file");
rval = false;
}
if (ssl->ssl_cert && ssl->ssl_key)
{
/** Load the server certificate */
if (SSL_CTX_use_certificate_chain_file(ctx, ssl->ssl_cert) <= 0)
{
MXS_ERROR("Failed to set server SSL certificate: %s", get_ssl_errors());
rval = false;
}
/* Load the private-key corresponding to the server certificate */
if (SSL_CTX_use_PrivateKey_file(ctx, ssl->ssl_key, SSL_FILETYPE_PEM) <= 0)
{
MXS_ERROR("Failed to set server SSL key: %s", get_ssl_errors());
rval = false;
}
/* Check if the server certificate and private-key matches */
if (!SSL_CTX_check_private_key(ctx))
{
MXS_ERROR("Server SSL certificate and key do not match: %s", get_ssl_errors());
rval = false;
}
}
/* Set to require peer (client) certificate verification */
if (ssl->ssl_verify_peer_certificate)
{
SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, NULL);
}
/* Set the verification depth */
SSL_CTX_set_verify_depth(ctx, ssl->ssl_cert_verify_depth);
if (rval)
{
ssl->ssl_init_done = true;
ssl->ctx = ctx;
}
else
{
SSL_CTX_free(ctx);
}
return rval;
}
void SSL_LISTENER_free(mxs::SSLContext* ssl)
{
if (ssl)
{
SSL_CTX_free(ssl->ctx);
MXS_FREE(ssl->ssl_ca_cert);
MXS_FREE(ssl->ssl_cert);
MXS_FREE(ssl->ssl_key);
MXS_FREE(ssl);
}
}