sslutils.c - platform/external/libpcap - Git at Google

 /*
  * Copyright (c) 2002 - 2003
  * NetGroup, Politecnico di Torino (Italy)
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  * notice, this list of conditions and the following disclaimer in the
  * documentation and/or other materials provided with the distribution.
  * 3. Neither the name of the Politecnico di Torino nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  */

 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif

 #ifdef HAVE_OPENSSL
 #include <stdlib.h>

 #include "portability.h"

 #include "sslutils.h"

 static const char *ssl_keyfile = "";   //!< file containing the private key in PEM format
 static const char *ssl_certfile = "";  //!< file containing the server's certificate in PEM format
 static const char *ssl_rootfile = "";  //!< file containing the list of CAs trusted by the client
 // TODO: a way to set ssl_rootfile from the command line, or an envvar?

 // TODO: lock?
 static SSL_CTX *ctx;

 void ssl_set_certfile(const char *certfile)
 {
 	ssl_certfile = certfile;
 }

 void ssl_set_keyfile(const char *keyfile)
 {
 	ssl_keyfile = keyfile;
 }

 int ssl_init_once(int is_server, int enable_compression, char *errbuf, size_t errbuflen)
 {
 	static int inited = 0;
 	if (inited) return 0;

 	SSL_library_init();
 	SSL_load_error_strings();
 	OpenSSL_add_ssl_algorithms();
 	if (enable_compression)
 		SSL_COMP_get_compression_methods();

 	SSL_METHOD const *meth =
 	    is_server ? SSLv23_server_method() : SSLv23_client_method();
 	ctx = SSL_CTX_new(meth);
 	if (! ctx)
 	{
 		snprintf(errbuf, errbuflen, "Cannot get a new SSL context: %s", ERR_error_string(ERR_get_error(), NULL));
 		goto die;
 	}

 	SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY);

 	if (is_server)
 	{
 		char const *certfile = ssl_certfile[0] ? ssl_certfile : "cert.pem";
 		if (1 != SSL_CTX_use_certificate_file(ctx, certfile, SSL_FILETYPE_PEM))
 		{
 			snprintf(errbuf, errbuflen, "Cannot read certificate file %s: %s", certfile, ERR_error_string(ERR_get_error(), NULL));
 			goto die;
 		}

 		char const *keyfile = ssl_keyfile[0] ? ssl_keyfile : "key.pem";
 		if (1 != SSL_CTX_use_PrivateKey_file(ctx, keyfile, SSL_FILETYPE_PEM))
 		{
 			snprintf(errbuf, errbuflen, "Cannot read private key file %s: %s", keyfile, ERR_error_string(ERR_get_error(), NULL));
 			goto die;
 		}
 	}
 	else
 	{
 		if (ssl_rootfile[0])
 		{
 			if (! SSL_CTX_load_verify_locations(ctx, ssl_rootfile, 0))
 			{
 				snprintf(errbuf, errbuflen, "Cannot read CA list from %s", ssl_rootfile);
 				goto die;
 			}
 		}
 		else
 		{
 			SSL_CTX_set_verify(ctx, SSL_VERIFY_NONE, NULL);
 		}
 	}

 #if 0
 	if (! RAND_load_file(RANDOM, 1024*1024))
 	{
 		snprintf(errbuf, errbuflen, "Cannot init random");
 		goto die;
 	}

 	if (is_server)
 	{
 		SSL_CTX_set_session_id_context(ctx, (void *)&s_server_session_id_context, sizeof(s_server_session_id_context));
 	}
 #endif

 	inited = 1;
 	return 0;

 die:
 	return -1;
 }

 SSL *ssl_promotion(int is_server, PCAP_SOCKET s, char *errbuf, size_t errbuflen)
 {
 	if (ssl_init_once(is_server, 1, errbuf, errbuflen) < 0) {
 		return NULL;
 	}

 	SSL *ssl = SSL_new(ctx); // TODO: also a DTLS context
 	SSL_set_fd(ssl, (int)s);

 	if (is_server) {
 		if (SSL_accept(ssl) <= 0) {
 			snprintf(errbuf, errbuflen, "SSL_accept(): %s",
 					ERR_error_string(ERR_get_error(), NULL));
 			return NULL;
 		}
 	} else {
 		if (SSL_connect(ssl) <= 0) {
 			snprintf(errbuf, errbuflen, "SSL_connect(): %s",
 					ERR_error_string(ERR_get_error(), NULL));
 			return NULL;
 		}
 	}

 	return ssl;
 }

 // Finish using an SSL handle; shut down the connection and free the
 // handle.
 void ssl_finish(SSL *ssl)
 {
 	//
 	// We won't be using this again, so we can just send the
 	// shutdown alert and free up the handle, and have our
 	// caller close the socket.
 	//
 	// XXX - presumably, if the connection is shut down on
 	// our side, either our peer won't have a problem sending
 	// their shutdown alert or will not treat such a problem
 	// as an error.  If this causes errors to be reported,
 	// fix that as appropriate.
 	//
 	SSL_shutdown(ssl);
 	SSL_free(ssl);
 }

 // Same return value as sock_send:
 // 0 on OK, -1 on error but closed connection (-2).
 int ssl_send(SSL *ssl, char const *buffer, int size, char *errbuf, size_t errbuflen)
 {
 	int status = SSL_write(ssl, buffer, size);
 	if (status > 0)
 	{
 		// "SSL_write() will only return with success, when the complete contents (...) has been written."
 		return 0;
 	}
 	else
 	{
 		int ssl_err = SSL_get_error(ssl, status); // TODO: does it pop the error?
 		if (ssl_err == SSL_ERROR_ZERO_RETURN)
 		{
 			return -2;
 		}
 		else if (ssl_err == SSL_ERROR_SYSCALL)
 		{
 #ifndef _WIN32
 			if (errno == ECONNRESET || errno == EPIPE) return -2;
 #endif
 		}
 		snprintf(errbuf, errbuflen, "SSL_write(): %s",
 		    ERR_error_string(ERR_get_error(), NULL));
 		return -1;
 	}
 }

 // Returns the number of bytes read, or -1 on syserror, or -2 on SSL error.
 int ssl_recv(SSL *ssl, char *buffer, int size, char *errbuf, size_t errbuflen)
 {
 	int status = SSL_read(ssl, buffer, size);
 	if (status <= 0)
 	{
 		int ssl_err = SSL_get_error(ssl, status);
 		if (ssl_err == SSL_ERROR_ZERO_RETURN)
 		{
 			return 0;
 		}
 		else if (ssl_err == SSL_ERROR_SYSCALL)
 		{
 			return -1;
 		}
 		else
 		{
 			// Should not happen
 			snprintf(errbuf, errbuflen, "SSL_read(): %s",
 			    ERR_error_string(ERR_get_error(), NULL));
 			return -2;
 		}
 	}
 	else
 	{
 		return status;
 	}
 }

 #endif // HAVE_OPENSSL
	/*
	* Copyright (c) 2002 - 2003
	* NetGroup, Politecnico di Torino (Italy)
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	* 3. Neither the name of the Politecnico di Torino nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*
	*/

	#ifdef HAVE_CONFIG_H
	#include <config.h>
	#endif

	#ifdef HAVE_OPENSSL
	#include <stdlib.h>

	#include "portability.h"

	#include "sslutils.h"

	static const char *ssl_keyfile = ""; //!< file containing the private key in PEM format
	static const char *ssl_certfile = ""; //!< file containing the server's certificate in PEM format
	static const char *ssl_rootfile = ""; //!< file containing the list of CAs trusted by the client
	// TODO: a way to set ssl_rootfile from the command line, or an envvar?

	// TODO: lock?
	static SSL_CTX *ctx;

	void ssl_set_certfile(const char *certfile)
	{
	ssl_certfile = certfile;
	}

	void ssl_set_keyfile(const char *keyfile)
	{
	ssl_keyfile = keyfile;
	}

	int ssl_init_once(int is_server, int enable_compression, char *errbuf, size_t errbuflen)
	{
	static int inited = 0;
	if (inited) return 0;

	SSL_library_init();
	SSL_load_error_strings();
	OpenSSL_add_ssl_algorithms();
	if (enable_compression)
	SSL_COMP_get_compression_methods();

	SSL_METHOD const *meth =
	is_server ? SSLv23_server_method() : SSLv23_client_method();
	ctx = SSL_CTX_new(meth);
	if (! ctx)
	{
	snprintf(errbuf, errbuflen, "Cannot get a new SSL context: %s", ERR_error_string(ERR_get_error(), NULL));
	goto die;
	}

	SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY);

	if (is_server)
	{
	char const *certfile = ssl_certfile[0] ? ssl_certfile : "cert.pem";
	if (1 != SSL_CTX_use_certificate_file(ctx, certfile, SSL_FILETYPE_PEM))
	{
	snprintf(errbuf, errbuflen, "Cannot read certificate file %s: %s", certfile, ERR_error_string(ERR_get_error(), NULL));
	goto die;
	}

	char const *keyfile = ssl_keyfile[0] ? ssl_keyfile : "key.pem";
	if (1 != SSL_CTX_use_PrivateKey_file(ctx, keyfile, SSL_FILETYPE_PEM))
	{
	snprintf(errbuf, errbuflen, "Cannot read private key file %s: %s", keyfile, ERR_error_string(ERR_get_error(), NULL));
	goto die;
	}
	}
	else
	{
	if (ssl_rootfile[0])
	{
	if (! SSL_CTX_load_verify_locations(ctx, ssl_rootfile, 0))
	{
	snprintf(errbuf, errbuflen, "Cannot read CA list from %s", ssl_rootfile);
	goto die;
	}
	}
	else
	{
	SSL_CTX_set_verify(ctx, SSL_VERIFY_NONE, NULL);
	}
	}

	#if 0
	if (! RAND_load_file(RANDOM, 1024*1024))
	{
	snprintf(errbuf, errbuflen, "Cannot init random");
	goto die;
	}

	if (is_server)
	{
	SSL_CTX_set_session_id_context(ctx, (void *)&s_server_session_id_context, sizeof(s_server_session_id_context));
	}
	#endif

	inited = 1;
	return 0;

	die:
	return -1;
	}

	SSL ssl_promotion(int is_server, PCAP_SOCKET s, char errbuf, size_t errbuflen)
	{
	if (ssl_init_once(is_server, 1, errbuf, errbuflen) < 0) {
	return NULL;
	}

	SSL *ssl = SSL_new(ctx); // TODO: also a DTLS context
	SSL_set_fd(ssl, (int)s);

	if (is_server) {
	if (SSL_accept(ssl) <= 0) {
	snprintf(errbuf, errbuflen, "SSL_accept(): %s",
	ERR_error_string(ERR_get_error(), NULL));
	return NULL;
	}
	} else {
	if (SSL_connect(ssl) <= 0) {
	snprintf(errbuf, errbuflen, "SSL_connect(): %s",
	ERR_error_string(ERR_get_error(), NULL));
	return NULL;
	}
	}

	return ssl;
	}

	// Finish using an SSL handle; shut down the connection and free the
	// handle.
	void ssl_finish(SSL *ssl)
	{
	//
	// We won't be using this again, so we can just send the
	// shutdown alert and free up the handle, and have our
	// caller close the socket.
	//
	// XXX - presumably, if the connection is shut down on
	// our side, either our peer won't have a problem sending
	// their shutdown alert or will not treat such a problem
	// as an error. If this causes errors to be reported,
	// fix that as appropriate.
	//
	SSL_shutdown(ssl);
	SSL_free(ssl);
	}

	// Same return value as sock_send:
	// 0 on OK, -1 on error but closed connection (-2).
	int ssl_send(SSL ssl, char const buffer, int size, char *errbuf, size_t errbuflen)
	{
	int status = SSL_write(ssl, buffer, size);
	if (status > 0)
	{
	// "SSL_write() will only return with success, when the complete contents (...) has been written."
	return 0;
	}
	else
	{
	int ssl_err = SSL_get_error(ssl, status); // TODO: does it pop the error?
	if (ssl_err == SSL_ERROR_ZERO_RETURN)
	{
	return -2;
	}
	else if (ssl_err == SSL_ERROR_SYSCALL)
	{
	#ifndef _WIN32
	if (errno == ECONNRESET \|\| errno == EPIPE) return -2;
	#endif
	}
	snprintf(errbuf, errbuflen, "SSL_write(): %s",
	ERR_error_string(ERR_get_error(), NULL));
	return -1;
	}
	}

	// Returns the number of bytes read, or -1 on syserror, or -2 on SSL error.
	int ssl_recv(SSL ssl, char buffer, int size, char *errbuf, size_t errbuflen)
	{
	int status = SSL_read(ssl, buffer, size);
	if (status <= 0)
	{
	int ssl_err = SSL_get_error(ssl, status);
	if (ssl_err == SSL_ERROR_ZERO_RETURN)
	{
	return 0;
	}
	else if (ssl_err == SSL_ERROR_SYSCALL)
	{
	return -1;
	}
	else
	{
	// Should not happen
	snprintf(errbuf, errbuflen, "SSL_read(): %s",
	ERR_error_string(ERR_get_error(), NULL));
	return -2;
	}
	}
	else
	{
	return status;
	}
	}

	#endif // HAVE_OPENSSL