+/*********************************************************************
+*
+* File : $Source: /cvsroot/ijbswa/current/ssl.c,v $
+*
+* Purpose : File with TLS/SSL extension. Contains methods for
+* creating, using and closing TLS/SSL connections.
+*
+* Copyright : Written by and Copyright (c) 2017 Vaclav Svec. FIT CVUT.
+* Copyright (C) 2018-2019 by Fabian Keil <fk@fabiankeil.de>
+*
+* This program is free software; you can redistribute it
+* and/or modify it under the terms of the GNU General
+* Public License as published by the Free Software
+* Foundation; either version 2 of the License, or (at
+* your option) any later version.
+*
+* 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.
+*
+* The GNU General Public License should be included with
+* this file. If not, you can view it at
+* http://www.gnu.org/copyleft/gpl.html
+* or write to the Free Software Foundation, Inc., 59
+* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+*
+*********************************************************************/
+
+#include <string.h>
+#include <unistd.h>
+
+#if !defined(MBEDTLS_CONFIG_FILE)
+# include "mbedtls/config.h"
+#else
+# include MBEDTLS_CONFIG_FILE
+#endif
+
+#include "mbedtls/md5.h"
+#include "mbedtls/pem.h"
+#include "mbedtls/base64.h"
+#include "mbedtls/error.h"
+
+#include "project.h"
+#include "miscutil.h"
+#include "errlog.h"
+#include "jcc.h"
+#include "config.h"
+#include "ssl.h"
+
+
+/*
+ * Macros for searching begin and end of certificates.
+ * Necessary to convert structure mbedtls_x509_crt to crt file.
+ */
+#define PEM_BEGIN_CRT "-----BEGIN CERTIFICATE-----\n"
+#define PEM_END_CRT "-----END CERTIFICATE-----\n"
+
+/*
+ * Macros for ssl.c
+ */
+#define ERROR_BUF_SIZE 1024 /* Size of buffer for error messages */
+#define CERTIFICATE_BUF_SIZE 16384 /* Size of buffer to save certificate. Value 4096 is mbedtls library buffer size for certificate in DER form */
+#define PRIVATE_KEY_BUF_SIZE 16000 /* Size of buffer to save private key. Value 16000 is taken from mbed TLS library examples. */
+#define RSA_KEY_PUBLIC_EXPONENT 65537 /* Public exponent for RSA private key generating */
+#define RSA_KEYSIZE 2048 /* Size of generated RSA keys */
+#define GENERATED_CERT_VALID_FROM "20100101000000" /* Date and time, which will be set in generated certificates as parameter valid from */
+#define GENERATED_CERT_VALID_TO "20401231235959" /* Date and time, which will be setted in generated certificates as parameter valid to */
+#define CERT_SIGNATURE_ALGORITHM MBEDTLS_MD_SHA256 /* The MD algorithm to use for the signature */
+#define CERT_SERIAL_NUM_LENGTH 4 /* Bytes of hash to be used for creating serial number of certificate. Min=2 and max=16 */
+#define LIMIT_MUTEX_NUMBER /* If this macro is defined, mutexes count for generating private keys is changed from 65536 to 32 */
+#define INVALID_CERT_INFO_BUF_SIZE 2048 /* Size of buffer for message with information about reason of certificate invalidity. Data after the end of buffer will not be saved */
+#define CERT_PARAM_COMMON_NAME "CN="
+#define CERT_PARAM_ORGANIZATION ",O="
+#define CERT_PARAM_ORG_UNIT ",OU="
+#define CERT_PARAM_COUNTRY ",C=CZ"
+#define KEY_FILE_TYPE ".pem"
+#define CERT_FILE_TYPE ".crt"
+#define CERT_SUBJECT_PASSWORD ""
+#define CERT_INFO_PREFIX ""
+
+
+extern int generate_webpage_certificate(struct client_state * csp);
+static char * make_certs_path(const char * conf_dir, const char * file_name, const char * suffix);
+static int file_exists(const char * path);
+static int host_to_hash(struct client_state *csp);
+static int ssl_verify_callback(void *data, mbedtls_x509_crt *crt, int depth, uint32_t *flags);
+static void free_certificate_chain(struct client_state *csp);
+static unsigned int get_certificate_mutex_id(struct client_state *csp);
+static unsigned long get_certificate_serial(struct client_state *csp);
+static void free_client_ssl_structures(struct client_state *csp);
+static void free_server_ssl_structures(struct client_state *csp);
+static int seed_rng(struct client_state *csp);
+
+/*********************************************************************
+ *
+ * Function : client_use_ssl
+ *
+ * Description : Tests if client in current client state structure
+ * should use SSL connection or standard connection.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : If client should use TLS/SSL connection, 1 is returned.
+ * Otherwise 0 is returned.
+ *
+ *********************************************************************/
+extern int client_use_ssl(const struct client_state *csp)
+{
+ return csp->http->client_ssl;
+}
+
+
+/*********************************************************************
+ *
+ * Function : server_use_ssl
+ *
+ * Description : Tests if server in current client state structure
+ * should use SSL connection or standard connection.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : If server should use TLS/SSL connection, 1 is returned.
+ * Otherwise 0 is returned.
+ *
+ *********************************************************************/
+extern int server_use_ssl(const struct client_state *csp)
+{
+ return csp->http->server_ssl;
+}
+
+
+/*********************************************************************
+*
+* Function : is_ssl_pending
+*
+* Description : Tests if there are some waitting data on ssl connection
+*
+* Parameters :
+* 1 : ssl = SSL context to test
+*
+* Returns : 0 => No data are pending
+* >0 => Pending data length
+*
+*********************************************************************/
+extern size_t is_ssl_pending(mbedtls_ssl_context *ssl)
+{
+ if (ssl == NULL)
+ {
+ return 0;
+ }
+
+ return mbedtls_ssl_get_bytes_avail(ssl);
+}
+
+
+/*********************************************************************
+ *
+ * Function : ssl_send_data
+ *
+ * Description : Sends the content of buf (for n bytes) to given SSL
+ * connection context.
+ *
+ * Parameters :
+ * 1 : ssl = SSL context to send data to
+ * 2 : buf = Pointer to data to be sent
+ * 3 : len = Length of data to be sent to the SSL context
+ *
+ * Returns : Length of sent data or negative value on error.
+ *
+ *********************************************************************/
+extern int ssl_send_data(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len)
+{
+ int ret = 0;
+ size_t max_fragment_size = 0; /* Maximal length of data in one SSL fragment*/
+ int send_len = 0; /* length of one data part to send */
+ int pos = 0; /* Position of unsent part in buffer */
+
+ if (len == 0)
+ {
+ return 0;
+ }
+
+ /* Getting maximal length of data sent in one fragment */
+ max_fragment_size = mbedtls_ssl_get_max_frag_len(ssl);
+
+ /*
+ * Whole buffer must be sent in many fragments, because each fragment
+ * has its maximal length.
+ */
+ while (pos < len)
+ {
+ /* Compute length of data, that can be send in next fragment */
+ if ((pos + (int)max_fragment_size) > len)
+ {
+ send_len = (int)len - pos;
+ }
+ else
+ {
+ send_len = (int)max_fragment_size;
+ }
+
+ /*
+ * Sending one part of the buffer
+ */
+ while ((ret = mbedtls_ssl_write(ssl,
+ (const unsigned char *)(buf + pos),
+ (size_t)send_len)) < 0)
+ {
+ if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
+ ret != MBEDTLS_ERR_SSL_WANT_WRITE)
+ {
+ char err_buf[ERROR_BUF_SIZE];
+
+ memset(err_buf, 0, sizeof(err_buf));
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "Sending data over TLS/SSL failed: %s", err_buf);
+ return -1;
+ }
+ }
+ /* Adding count of sent bytes to position in buffer */
+ pos = pos + send_len;
+ }
+
+ return (int)len;
+}
+
+
+/*********************************************************************
+ *
+ * Function : ssl_recv_data
+ *
+ * Description : Receives data from given SSL context and puts
+ * it into buffer.
+ *
+ * Parameters :
+ * 1 : ssl = SSL context to receive data from
+ * 2 : buf = Pointer to buffer where data will be written
+ * 3 : max_length = Maximum number of bytes to read
+ *
+ * Returns : Number of bytes read, 0 for EOF, or negative
+ * value on error.
+ *
+ *********************************************************************/
+extern int ssl_recv_data(mbedtls_ssl_context *ssl, unsigned char *buf, size_t max_length)
+{
+ int ret = 0;
+ memset(buf, 0, max_length);
+
+ /*
+ * Receiving data from SSL context into buffer
+ */
+ do
+ {
+ ret = mbedtls_ssl_read(ssl, buf, max_length);
+ } while (ret == MBEDTLS_ERR_SSL_WANT_READ
+ || ret == MBEDTLS_ERR_SSL_WANT_WRITE);
+
+ if (ret < 0)
+ {
+ char err_buf[ERROR_BUF_SIZE];
+
+ memset(err_buf, 0, sizeof(err_buf));
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "Receiving data over TLS/SSL failed: %s", err_buf);
+ }
+
+ return ret;
+}
+
+
+/*********************************************************************
+ *
+ * Function : ssl_flush_socket
+ *
+ * Description : Send any pending "buffered" content with given
+ * SSL connection. Alternative to function flush_socket.
+ *
+ * Parameters :
+ * 1 : ssl = SSL context to send buffer to
+ * 2 : iob = The I/O buffer to flush, usually csp->iob.
+ *
+ * Returns : On success, the number of bytes send are returned (zero
+ * indicates nothing was sent). On error, -1 is returned.
+ *
+ *********************************************************************/
+extern long ssl_flush_socket(mbedtls_ssl_context *ssl, struct iob *iob)
+{
+ /* Computing length of buffer part to send */
+ long len = iob->eod - iob->cur;
+
+ if (len <= 0)
+ {
+ return(0);
+ }
+
+ /* Sending data to given SSl context */
+ if (ssl_send_data(ssl, (const unsigned char *)iob->cur, (size_t)len) < 0)
+ {
+ return -1;
+ }
+ iob->eod = iob->cur = iob->buf;
+ return(len);
+}
+
+
+/*********************************************************************
+ *
+ * Function : ssl_debug_callback
+ *
+ * Description : Debug callback function for mbedtls library.
+ * Prints info into log file.
+ *
+ * Parameters :
+ * 1 : ctx = File to save log in
+ * 2 : level = Debug level
+ * 3 : file = File calling debug message
+ * 4 : line = Line calling debug message
+ * 5 : str = Debug message
+ *
+ * Returns : N/A
+ *
+ *********************************************************************/
+static void ssl_debug_callback(void *ctx, int level, const char *file, int line, const char *str)
+{
+ /*
+ ((void)level);
+ fprintf((FILE *)ctx, "%s:%04d: %s", file, line, str);
+ fflush((FILE *)ctx);
+ log_error(LOG_LEVEL_INFO, "SSL debug message: %s:%04d: %s", file, line, str);
+ */
+}
+
+
+/*********************************************************************
+ *
+ * Function : create_client_ssl_connection
+ *
+ * Description : Creates TLS/SSL secured connection with client
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : 0 on success, negative value if connection wasn't created
+ * successfully.
+ *
+ *********************************************************************/
+extern int create_client_ssl_connection(struct client_state *csp)
+{
+ /* Paths to certificates file and key file */
+ char *key_file = NULL;
+ char *ca_file = NULL;
+ char *cert_file = NULL;
+ int ret = 0;
+ char err_buf[ERROR_BUF_SIZE];
+
+ memset(err_buf, 0, sizeof(err_buf));
+
+ /*
+ * Initializing mbedtls structures for TLS/SSL connection
+ */
+ mbedtls_net_init(&(csp->mbedtls_client_attr.socket_fd));
+ mbedtls_ssl_init(&(csp->mbedtls_client_attr.ssl));
+ mbedtls_ssl_config_init(&(csp->mbedtls_client_attr.conf));
+ mbedtls_x509_crt_init(&(csp->mbedtls_client_attr.server_cert));
+ mbedtls_pk_init(&(csp->mbedtls_client_attr.prim_key));
+#if defined(MBEDTLS_SSL_CACHE_C)
+ mbedtls_ssl_cache_init(&(csp->mbedtls_client_attr.cache));
+#endif
+
+ /*
+ * Preparing hash of host for creating certificates
+ */
+ ret = host_to_hash(csp);
+ if (ret != 0)
+ {
+ log_error(LOG_LEVEL_ERROR, "Generating hash of host failed: %d", ret);
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Preparing paths to certificates files and key file
+ */
+ ca_file = csp->config->ca_cert_file;
+ cert_file = make_certs_path(csp->config->certificate_directory,
+ (const char *)csp->http->hash_of_host_hex, CERT_FILE_TYPE);
+ key_file = make_certs_path(csp->config->certificate_directory,
+ (const char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE);
+
+ if (cert_file == NULL || key_file == NULL)
+ {
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Generating certificate for requested host. Mutex to prevent
+ * certificate and key inconsistence must be locked.
+ */
+ unsigned int cert_mutex_id = get_certificate_mutex_id(csp);
+ privoxy_mutex_lock(&(certificates_mutexes[cert_mutex_id]));
+
+ ret = generate_webpage_certificate(csp);
+ if (ret < 0)
+ {
+ log_error(LOG_LEVEL_ERROR,
+ "Generate_webpage_certificate failed: %d", ret);
+ privoxy_mutex_unlock(&(certificates_mutexes[cert_mutex_id]));
+ ret = -1;
+ goto exit;
+ }
+ privoxy_mutex_unlock(&(certificates_mutexes[cert_mutex_id]));
+
+ /*
+ * Seed the RNG
+ */
+ ret = seed_rng(csp);
+ if (ret != 0)
+ {
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Loading CA file, webpage certificate and key files
+ */
+ ret = mbedtls_x509_crt_parse_file(&(csp->mbedtls_client_attr.server_cert),
+ cert_file);
+ if (ret != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "Loading webpage certificate %s failed: %s", cert_file, err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ ret = mbedtls_x509_crt_parse_file(&(csp->mbedtls_client_attr.server_cert),
+ ca_file);
+ if (ret != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "Loading CA certificate %s failed: %s", ca_file, err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ ret = mbedtls_pk_parse_keyfile(&(csp->mbedtls_client_attr.prim_key),
+ key_file, NULL);
+ if (ret != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "Loading and parsing webpage certificate private key %s failed: %s",
+ key_file, err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Setting SSL parameters
+ */
+ ret = mbedtls_ssl_config_defaults(&(csp->mbedtls_client_attr.conf),
+ MBEDTLS_SSL_IS_SERVER, MBEDTLS_SSL_TRANSPORT_STREAM,
+ MBEDTLS_SSL_PRESET_DEFAULT);
+ if (ret != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "mbedtls_ssl_config_defaults failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ mbedtls_ssl_conf_rng(&(csp->mbedtls_client_attr.conf),
+ mbedtls_ctr_drbg_random, &ctr_drbg);
+ mbedtls_ssl_conf_dbg(&(csp->mbedtls_client_attr.conf),
+ ssl_debug_callback, stdout);
+
+#if defined(MBEDTLS_SSL_CACHE_C)
+ mbedtls_ssl_conf_session_cache(&(csp->mbedtls_client_attr.conf),
+ &(csp->mbedtls_client_attr.cache), mbedtls_ssl_cache_get,
+ mbedtls_ssl_cache_set);
+#endif
+
+ /*
+ * Setting certificates
+ */
+ ret = mbedtls_ssl_conf_own_cert(&(csp->mbedtls_client_attr.conf),
+ &(csp->mbedtls_client_attr.server_cert),
+ &(csp->mbedtls_client_attr.prim_key));
+ if (ret != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "mbedtls_ssl_conf_own_cert failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ ret = mbedtls_ssl_setup(&(csp->mbedtls_client_attr.ssl),
+ &(csp->mbedtls_client_attr.conf));
+ if (ret != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_setup failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ mbedtls_ssl_set_bio(&(csp->mbedtls_client_attr.ssl),
+ &(csp->mbedtls_client_attr.socket_fd), mbedtls_net_send,
+ mbedtls_net_recv, NULL);
+ mbedtls_ssl_session_reset(&(csp->mbedtls_client_attr.ssl));
+
+ /*
+ * Setting socket fd in mbedtls_net_context structure. This structure
+ * can't be set by mbedtls functions, because we already have created
+ * a TCP connection when this function is called.
+ */
+ csp->mbedtls_client_attr.socket_fd.fd = csp->cfd;
+
+ /*
+ * Handshake with client
+ */
+ log_error(LOG_LEVEL_CONNECT,
+ "Performing the TLS/SSL handshake with client. Hash of host: %s",
+ csp->http->hash_of_host_hex);
+ while ((ret = mbedtls_ssl_handshake(&(csp->mbedtls_client_attr.ssl))) != 0)
+ {
+ if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
+ ret != MBEDTLS_ERR_SSL_WANT_WRITE)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "medtls_ssl_handshake with client failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+ }
+
+ log_error(LOG_LEVEL_CONNECT, "Client successfully connected over TLS/SSL");
+ csp->ssl_with_client_is_opened = 1;
+
+exit:
+ /*
+ * Freeing allocated paths to files
+ */
+ freez(cert_file);
+ freez(key_file);
+
+ /* Freeing structures if connection wasn't created successfully */
+ if (ret < 0)
+ {
+ free_client_ssl_structures(csp);
+ }
+ return ret;
+}
+
+
+/*********************************************************************
+ *
+ * Function : close_client_ssl_connection
+ *
+ * Description : Closes TLS/SSL connection with client. This function
+ * checks if this connection is already created.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : N/A
+ *
+ *********************************************************************/
+static void close_client_ssl_connection(struct client_state *csp)
+{
+ int ret = 0;
+
+ if (csp->ssl_with_client_is_opened == 0)
+ {
+ return;
+ }
+
+ /*
+ * Notifying the peer that the connection is being closed.
+ */
+ do {
+ ret = mbedtls_ssl_close_notify(&(csp->mbedtls_client_attr.ssl));
+ } while (ret == MBEDTLS_ERR_SSL_WANT_WRITE);
+
+ free_client_ssl_structures(csp);
+ csp->ssl_with_client_is_opened = 0;
+}
+
+
+/*********************************************************************
+ *
+ * Function : free_client_ssl_structures
+ *
+ * Description : Frees structures used for SSL communication with
+ * client.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : N/A
+ *
+ *********************************************************************/
+static void free_client_ssl_structures(struct client_state *csp)
+{
+ /*
+ * We can't use function mbedtls_net_free, because this function
+ * inter alia close TCP connection on setted fd. Instead of this
+ * function, we change fd to -1, which is the same what does
+ * rest of mbedtls_net_free function.
+ */
+ csp->mbedtls_client_attr.socket_fd.fd = -1;
+
+ /* Freeing mbedtls structures */
+ mbedtls_x509_crt_free(&(csp->mbedtls_client_attr.server_cert));
+ mbedtls_pk_free(&(csp->mbedtls_client_attr.prim_key));
+ mbedtls_ssl_free(&(csp->mbedtls_client_attr.ssl));
+ mbedtls_ssl_config_free(&(csp->mbedtls_client_attr.conf));
+#if defined(MBEDTLS_SSL_CACHE_C)
+ mbedtls_ssl_cache_free(&(csp->mbedtls_client_attr.cache));
+#endif
+}
+
+
+/*********************************************************************
+ *
+ * Function : create_server_ssl_connection
+ *
+ * Description : Creates TLS/SSL secured connection with server.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : 0 on success, negative value if connection wasn't created
+ * successfully.
+ *
+ *********************************************************************/
+extern int create_server_ssl_connection(struct client_state *csp)
+{
+ int ret = 0;
+ char err_buf[ERROR_BUF_SIZE];
+ char *trusted_cas_file = NULL;
+ int auth_mode = MBEDTLS_SSL_VERIFY_REQUIRED;
+
+ memset(err_buf, 0, sizeof(err_buf));
+
+ csp->server_cert_verification_result = SSL_CERT_NOT_VERIFIED;
+ csp->server_certs_chain.next = NULL;
+
+ /* Setting path to file with trusted CAs */
+ trusted_cas_file = csp->config->trusted_cas_file;
+
+ /*
+ * Initializing mbedtls structures for TLS/SSL connection
+ */
+ mbedtls_net_init(&(csp->mbedtls_server_attr.socket_fd));
+ mbedtls_ssl_init(&(csp->mbedtls_server_attr.ssl));
+ mbedtls_ssl_config_init(&(csp->mbedtls_server_attr.conf));
+ mbedtls_x509_crt_init( &(csp->mbedtls_server_attr.ca_cert));
+
+ /*
+ * Setting socket fd in mbedtls_net_context structure. This structure
+ * can't be set by mbedtls functions, because we already have created
+ * TCP connection when calling this function.
+ */
+ csp->mbedtls_server_attr.socket_fd.fd = csp->server_connection.sfd;
+
+ /*
+ * Seed the RNG
+ */
+ ret = seed_rng(csp);
+ if (ret != 0)
+ {
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Loading file with trusted CAs
+ */
+ ret = mbedtls_x509_crt_parse_file(&(csp->mbedtls_server_attr.ca_cert),
+ trusted_cas_file);
+ if (ret < 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR, "Loading trusted CAs file %s failed: %s",
+ trusted_cas_file, err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Set TLS/SSL options
+ */
+ ret = mbedtls_ssl_config_defaults(&(csp->mbedtls_server_attr.conf),
+ MBEDTLS_SSL_IS_CLIENT,
+ MBEDTLS_SSL_TRANSPORT_STREAM,
+ MBEDTLS_SSL_PRESET_DEFAULT);
+ if (ret != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_config_defaults failed: %s",
+ err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Setting how strict should certificate verification be and other
+ * parameters for certificate verification
+ */
+ if (csp->dont_verify_certificate)
+ {
+ auth_mode = MBEDTLS_SSL_VERIFY_NONE;
+ }
+
+ mbedtls_ssl_conf_authmode(&(csp->mbedtls_server_attr.conf), auth_mode);
+ mbedtls_ssl_conf_ca_chain(&(csp->mbedtls_server_attr.conf),
+ &(csp->mbedtls_server_attr.ca_cert), NULL);
+
+ /* Setting callback function for certificates verification */
+ mbedtls_ssl_conf_verify(&(csp->mbedtls_server_attr.conf),
+ ssl_verify_callback, (void *)csp);
+
+ mbedtls_ssl_conf_rng(&(csp->mbedtls_server_attr.conf),
+ mbedtls_ctr_drbg_random, &ctr_drbg);
+ mbedtls_ssl_conf_dbg(&(csp->mbedtls_server_attr.conf),
+ ssl_debug_callback, stdout);
+
+ ret = mbedtls_ssl_setup(&(csp->mbedtls_server_attr.ssl),
+ &(csp->mbedtls_server_attr.conf));
+ if (ret != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_setup failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Set the hostname to check against the received server certificate
+ */
+ ret = mbedtls_ssl_set_hostname(&(csp->mbedtls_server_attr.ssl),
+ csp->http->host);
+ if (ret != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_set_hostname failed: %s",
+ err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ mbedtls_ssl_set_bio(&(csp->mbedtls_server_attr.ssl),
+ &(csp->mbedtls_server_attr.socket_fd), mbedtls_net_send,
+ mbedtls_net_recv, NULL);
+
+ /*
+ * Handshake with server
+ */
+ log_error(LOG_LEVEL_CONNECT,
+ "Performing the TLS/SSL handshake with server");
+
+ while ((ret = mbedtls_ssl_handshake(&(csp->mbedtls_server_attr.ssl))) != 0)
+ {
+ if (ret != MBEDTLS_ERR_SSL_WANT_READ
+ && ret != MBEDTLS_ERR_SSL_WANT_WRITE)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+
+ if (ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED)
+ {
+ log_error(LOG_LEVEL_ERROR,
+ "Server certificate verification failed: %s", err_buf);
+ csp->server_cert_verification_result =
+ mbedtls_ssl_get_verify_result(&(csp->mbedtls_server_attr.ssl));
+
+ ret = -1;
+ }
+ else
+ {
+ log_error(LOG_LEVEL_ERROR,
+ "mbedtls_ssl_handshake with server failed: %s", err_buf);
+ ret = -1;
+ }
+ goto exit;
+ }
+ }
+
+ log_error(LOG_LEVEL_CONNECT, "Server successfully connected over TLS/SSL");
+
+ /*
+ * Server certificate chain is valid, so we can clean
+ * chain, because we will not send it to client.
+ */
+ free_certificate_chain(csp);
+
+ csp->ssl_with_server_is_opened = 1;
+ csp->server_cert_verification_result =
+ mbedtls_ssl_get_verify_result(&(csp->mbedtls_server_attr.ssl));
+
+exit:
+ /* Freeing structures if connection wasn't created successfully */
+ if (ret < 0)
+ {
+ free_server_ssl_structures(csp);
+ }
+
+ return ret;
+}
+
+
+/*********************************************************************
+ *
+ * Function : close_server_ssl_connection
+ *
+ * Description : Closes TLS/SSL connection with server. This function
+ * checks if this connection is already opened.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : N/A
+ *
+ *********************************************************************/
+static void close_server_ssl_connection(struct client_state *csp)
+{
+ int ret = 0;
+
+ if (csp->ssl_with_server_is_opened == 0)
+ {
+ return;
+ }
+
+ /*
+ * Notifying the peer that the connection is being closed.
+ */
+ do {
+ ret = mbedtls_ssl_close_notify(&(csp->mbedtls_server_attr.ssl));
+ } while (ret == MBEDTLS_ERR_SSL_WANT_WRITE);
+
+ free_server_ssl_structures(csp);
+ csp->ssl_with_server_is_opened = 0;
+}
+
+
+/*********************************************************************
+ *
+ * Function : free_server_ssl_structures
+ *
+ * Description : Frees structures used for SSL communication with server
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : N/A
+ *
+ *********************************************************************/
+static void free_server_ssl_structures(struct client_state *csp)
+{
+ /*
+ * We can't use function mbedtls_net_free, because this function
+ * inter alia close TCP connection on setted fd. Instead of this
+ * function, we change fd to -1, which is the same what does
+ * rest of mbedtls_net_free function.
+ */
+ csp->mbedtls_client_attr.socket_fd.fd = -1;
+
+ mbedtls_x509_crt_free(&(csp->mbedtls_server_attr.ca_cert));
+ mbedtls_ssl_free(&(csp->mbedtls_server_attr.ssl));
+ mbedtls_ssl_config_free(&(csp->mbedtls_server_attr.conf));
+}
+
+
+/*********************************************************************
+ * Function : close_client_and_server_ssl_connections
+ *
+ * Description : Checks if client or server should use secured
+ * connection over SSL and if so, closes all of them.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : N/A
+ *
+ *********************************************************************/
+extern void close_client_and_server_ssl_connections(struct client_state *csp)
+{
+ if (client_use_ssl(csp) == 1)
+ {
+ close_client_ssl_connection(csp);
+ }
+ if (server_use_ssl(csp) == 1)
+ {
+ close_server_ssl_connection(csp);
+ }
+}
+
+/*====================== Certificates ======================*/
+
+/*********************************************************************
+ * Function : write_certificate
+ *
+ * Description : Writes certificate into file.
+ *
+ * Parameters :
+ * 1 : crt = certificate to write into file
+ * 2 : output_file = path to save certificate file
+ * 3 : f_rng = mbedtls_ctr_drbg_random
+ * 4 : p_rng = mbedtls_ctr_drbg_context
+ *
+ * Returns : Length of written certificate on success or negative value
+ * on error
+ *
+ *********************************************************************/
+static int write_certificate(mbedtls_x509write_cert *crt, const char *output_file,
+ int(*f_rng)(void *, unsigned char *, size_t), void *p_rng)
+{
+ FILE *f = NULL;
+ size_t len = 0;
+ unsigned char cert_buf[CERTIFICATE_BUF_SIZE + 1]; /* Buffer for certificate in PEM format + terminating NULL */
+ int ret = 0;
+ char err_buf[ERROR_BUF_SIZE];
+
+ memset(err_buf, 0, sizeof(err_buf));
+ memset(cert_buf, 0, sizeof(cert_buf));
+
+ /*
+ * Writing certificate into PEM string. If buffer is too small, fuction
+ * returns specific error and no buffer overflow can happen.
+ */
+ if ((ret = mbedtls_x509write_crt_pem(crt, cert_buf,
+ sizeof(cert_buf) - 1, f_rng, p_rng)) != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "Writing certificate into buffer failed: %s", err_buf);
+ return -1;
+ }
+
+ len = strlen((char *)cert_buf);
+
+ /*
+ * Saving certificate into file
+ */
+ if ((f = fopen(output_file, "w")) == NULL)
+ {
+ log_error(LOG_LEVEL_ERROR, "Opening file %s to save certificate failed",
+ output_file);
+ return -1;
+ }
+
+ if (fwrite(cert_buf, 1, len, f) != len)
+ {
+ log_error(LOG_LEVEL_ERROR,
+ "Writing certificate into file %s failed", output_file);
+ fclose(f);
+ return -1;
+ }
+
+ fclose(f);
+
+ return (int)len;
+}
+
+
+/*********************************************************************
+ * Function : write_private_key
+ *
+ * Description : Writes private key into file and copies saved
+ * content into given pointer to string. If function
+ * returns 0 for success, this copy must be freed by
+ * caller.
+ *
+ * Parameters :
+ * 1 : key = key to write into file
+ * 2 : ret_buf = pointer to string with created key file content
+ * 3 : key_file_path = path where to save key file
+ *
+ * Returns : Length of written private key on success or negative value
+ * on error
+ *
+ *********************************************************************/
+static int write_private_key(mbedtls_pk_context *key, unsigned char **ret_buf,
+ const char *key_file_path)
+{
+ size_t len = 0; /* Length of created key */
+ FILE *f = NULL; /* File to save certificate */
+ int ret = 0;
+ char err_buf[ERROR_BUF_SIZE];
+
+ memset(err_buf, 0, sizeof(err_buf));
+
+ /* Initializing buffer for key file content */
+ *ret_buf = (unsigned char *)malloc(PRIVATE_KEY_BUF_SIZE + 1);
+ if (*ret_buf == NULL)
+ {
+ log_error(LOG_LEVEL_ERROR,
+ "Creating buffer for private key failed: malloc fail");
+ ret = -1;
+ goto exit;
+ }
+ memset(*ret_buf, 0, PRIVATE_KEY_BUF_SIZE + 1);
+
+ /*
+ * Writing private key into PEM string
+ */
+ if ((ret = mbedtls_pk_write_key_pem(key, *ret_buf, PRIVATE_KEY_BUF_SIZE)) != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "Writing private key into PEM string failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+ len = strlen((char *)*ret_buf);
+
+ /*
+ * Saving key into file
+ */
+ if ((f = fopen(key_file_path, "wb")) == NULL)
+ {
+ log_error(LOG_LEVEL_ERROR,
+ "Opening file %s to save private key failed: %E",
+ key_file_path);
+ ret = -1;
+ goto exit;
+ }
+
+ if (fwrite(*ret_buf, 1, len, f) != len)
+ {
+ fclose(f);
+ log_error(LOG_LEVEL_ERROR,
+ "Writing private key into file %s failed",
+ key_file_path);
+ ret = -1;
+ goto exit;
+ }
+
+ fclose(f);
+
+exit:
+ if (ret < 0)
+ {
+ freez(*ret_buf);
+ *ret_buf = NULL;
+ return ret;
+ }
+ return (int)len;
+}
+
+
+/*********************************************************************
+ * Function : generate_key
+ *
+ * Description : Tests if private key for host saved in csp already
+ * exists. If this file doesn't exists, a new key is
+ * generated and saved in a file. The generated key is also
+ * copied into given parameter key_buf, which must be then
+ * freed by caller. If file with key exists, key_buf
+ * contain NULL and no private key is generated.
+ *
+ * Parameters :
+ * 1 : key_buf = buffer to save new generated key
+ * 2 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : -1 => Error while generating private key
+ * 0 => Key already exists
+ * >0 => Length of generated private key
+ *
+ *********************************************************************/
+static int generate_key(unsigned char **key_buf, struct client_state *csp)
+{
+ mbedtls_pk_context key;
+ key_options key_opt;
+ int ret = 0;
+ char err_buf[ERROR_BUF_SIZE];
+
+ key_opt.key_file_path = NULL;
+ memset(err_buf, 0, sizeof(err_buf));
+
+ /*
+ * Initializing structures for key generating
+ */
+ mbedtls_pk_init(&key);
+
+ /*
+ * Preparing path for key file and other properties for generating key
+ */
+ key_opt.type = MBEDTLS_PK_RSA;
+ key_opt.rsa_keysize = RSA_KEYSIZE;
+
+ key_opt.key_file_path = make_certs_path(csp->config->certificate_directory,
+ (char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE);
+ if (key_opt.key_file_path == NULL)
+ {
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Test if key already exists. If so, we don't have to create it again.
+ */
+ if (file_exists(key_opt.key_file_path) == 1)
+ {
+ ret = 0;
+ goto exit;
+ }
+
+ /*
+ * Seed the RNG
+ */
+ ret = seed_rng(csp);
+ if (ret != 0)
+ {
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Setting attributes of private key and generating it
+ */
+ if ((ret = mbedtls_pk_setup(&key,
+ mbedtls_pk_info_from_type(key_opt.type))) != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR, "mbedtls_pk_setup failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ ret = mbedtls_rsa_gen_key(mbedtls_pk_rsa(key), mbedtls_ctr_drbg_random,
+ &ctr_drbg, (unsigned)key_opt.rsa_keysize, RSA_KEY_PUBLIC_EXPONENT);
+ if (ret != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR, "Key generating failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Exporting private key into file
+ */
+ if ((ret = write_private_key(&key, key_buf, key_opt.key_file_path)) < 0)
+ {
+ log_error(LOG_LEVEL_ERROR,
+ "Writing private key into file %s failed", key_opt.key_file_path);
+ ret = -1;
+ goto exit;
+ }
+
+exit:
+ /*
+ * Freeing used variables
+ */
+ freez(key_opt.key_file_path);
+
+ mbedtls_pk_free(&key);
+
+ return ret;
+}
+
+
+/*********************************************************************
+ *
+ * Function : generate_webpage_certificate
+ *
+ * Description : Creates certificate file in presetted directory.
+ * If certificate already exists, no other certificate
+ * will be created. Subject of certificate is named
+ * by csp->http->host from parameter. This function also
+ * triggers generating of private key for new certificate.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : -1 => Error while creating certificate.
+ * 0 => Certificate alreaday exist.
+ * >0 => Length of created certificate.
+ *
+ *********************************************************************/
+extern int generate_webpage_certificate(struct client_state * csp)
+{
+ mbedtls_x509_crt issuer_cert;
+ mbedtls_pk_context loaded_issuer_key, loaded_subject_key;
+ mbedtls_pk_context *issuer_key = &loaded_issuer_key;
+ mbedtls_pk_context *subject_key = &loaded_subject_key;
+ mbedtls_x509write_cert cert;
+ mbedtls_mpi serial;
+
+ unsigned char *key_buf = NULL; /* Buffer for created key */
+
+ int ret = 0;
+ char err_buf[ERROR_BUF_SIZE];
+ cert_options cert_opt;
+
+ memset(err_buf, 0, sizeof(err_buf));
+
+ /* Paths to keys and certificates needed to create certificate */
+ cert_opt.issuer_key = NULL;
+ cert_opt.subject_key = NULL;
+ cert_opt.issuer_crt = NULL;
+ cert_opt.output_file = NULL;
+
+ /*
+ * Create key for requested host
+ */
+ int subject_key_len = generate_key(&key_buf, csp);
+ if (subject_key_len < 0)
+ {
+ log_error(LOG_LEVEL_ERROR, "Key generating failed");
+ return -1;
+ }
+
+ /*
+ * Initializing structures for certificate generating
+ */
+ mbedtls_x509write_crt_init(&cert);
+ mbedtls_x509write_crt_set_md_alg( &cert, CERT_SIGNATURE_ALGORITHM);
+ mbedtls_pk_init(&loaded_issuer_key);
+ mbedtls_pk_init(&loaded_subject_key);
+ mbedtls_mpi_init(&serial);
+ mbedtls_x509_crt_init(&issuer_cert);
+
+ /*
+ * Presetting parameters for certificate. We must compute total length
+ * of parameters.
+ */
+ size_t cert_params_len = strlen(CERT_PARAM_COMMON_NAME) +
+ strlen(CERT_PARAM_ORGANIZATION) + strlen(CERT_PARAM_COUNTRY) +
+ strlen(CERT_PARAM_ORG_UNIT) +
+ 3 * strlen(csp->http->host) + 1;
+ char cert_params[cert_params_len];
+ memset(cert_params, 0, cert_params_len);
+
+ /*
+ * Converting unsigned long serial number to char * serial number.
+ * We must compute length of serial number in string + terminating null.
+ */
+ unsigned long certificate_serial = get_certificate_serial(csp);
+ int serial_num_size = snprintf(NULL, 0, "%lu", certificate_serial) + 1;
+ if (serial_num_size <= 0)
+ {
+ serial_num_size = 1;
+ }
+
+ char serial_num_text[serial_num_size]; /* Buffer for serial number */
+ ret = snprintf(serial_num_text, (size_t)serial_num_size, "%lu", certificate_serial);
+ if (ret < 0 || ret >= serial_num_size)
+ {
+ log_error(LOG_LEVEL_ERROR,
+ "Converting certificate serial number into string failed");
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Preparing parameters for certificate
+ */
+ strlcpy(cert_params, CERT_PARAM_COMMON_NAME, cert_params_len);
+ strlcat(cert_params, csp->http->host, cert_params_len);
+ strlcat(cert_params, CERT_PARAM_ORGANIZATION, cert_params_len);
+ strlcat(cert_params, csp->http->host, cert_params_len);
+ strlcat(cert_params, CERT_PARAM_ORG_UNIT, cert_params_len);
+ strlcat(cert_params, csp->http->host, cert_params_len);
+ strlcat(cert_params, CERT_PARAM_COUNTRY, cert_params_len);
+
+ cert_opt.issuer_crt = csp->config->ca_cert_file;
+ cert_opt.issuer_key = csp->config->ca_key_file;
+ cert_opt.subject_key = make_certs_path(csp->config->certificate_directory,
+ (const char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE);
+ cert_opt.output_file = make_certs_path(csp->config->certificate_directory,
+ (const char *)csp->http->hash_of_host_hex, CERT_FILE_TYPE);
+
+ if (cert_opt.subject_key == NULL || cert_opt.output_file == NULL)
+ {
+ ret = -1;
+ goto exit;
+ }
+
+ cert_opt.subject_pwd = CERT_SUBJECT_PASSWORD;
+ cert_opt.issuer_pwd = csp->config->ca_password;
+ cert_opt.subject_name = cert_params;
+ cert_opt.not_before = GENERATED_CERT_VALID_FROM;
+ cert_opt.not_after = GENERATED_CERT_VALID_TO;
+ cert_opt.serial = serial_num_text;
+ cert_opt.is_ca = 0;
+ cert_opt.max_pathlen = -1;
+
+ /*
+ * Test if certificate exists and private key was already created
+ */
+ if (file_exists(cert_opt.output_file) == 1 && subject_key_len == 0)
+ {
+ ret = 0;
+ goto exit;
+ }
+
+ /*
+ * Seed the PRNG
+ */
+ ret = seed_rng(csp);
+ if (ret != 0)
+ {
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Parse serial to MPI
+ */
+ ret = mbedtls_mpi_read_string(&serial, 10, cert_opt.serial);
+ if (ret != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "mbedtls_mpi_read_string failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Loading certificates
+ */
+ ret = mbedtls_x509_crt_parse_file(&issuer_cert, cert_opt.issuer_crt);
+ if (ret != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR, "Loading issuer certificate %s failed: %s",
+ cert_opt.issuer_crt, err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ ret = mbedtls_x509_dn_gets(cert_opt.issuer_name,
+ sizeof(cert_opt.issuer_name), &issuer_cert.subject);
+ if (ret < 0)
+ {
+ mbedtls_strerror( ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR, "mbedtls_x509_dn_gets failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Loading keys from file or from buffer
+ */
+ if (key_buf != NULL && subject_key_len > 0)
+ {
+ /* Key was created in this function and is stored in buffer */
+ ret = mbedtls_pk_parse_key(&loaded_subject_key, key_buf,
+ (size_t)(subject_key_len + 1), (unsigned const char *)
+ cert_opt.subject_pwd, strlen(cert_opt.subject_pwd));
+ }
+ else
+ {
+ /* Key wasn't created in this function, because it already existed */
+ ret = mbedtls_pk_parse_keyfile(&loaded_subject_key,
+ cert_opt.subject_key, cert_opt.subject_pwd);
+ }
+
+ if (ret != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR, "Parsing subject key %s failed: %s",
+ cert_opt.subject_key, err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ ret = mbedtls_pk_parse_keyfile(&loaded_issuer_key, cert_opt.issuer_key,
+ cert_opt.issuer_pwd);
+ if (ret != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "Parsing issuer key %s failed: %s", cert_opt.issuer_key, err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Check if key and issuer certificate match
+ */
+ if (!mbedtls_pk_can_do(&issuer_cert.pk, MBEDTLS_PK_RSA) ||
+ mbedtls_mpi_cmp_mpi(&mbedtls_pk_rsa(issuer_cert.pk)->N,
+ &mbedtls_pk_rsa(*issuer_key)->N) != 0 ||
+ mbedtls_mpi_cmp_mpi( &mbedtls_pk_rsa(issuer_cert.pk)->E,
+ &mbedtls_pk_rsa(*issuer_key )->E) != 0)
+ {
+ log_error(LOG_LEVEL_ERROR,
+ "Issuer key doesn't match issuer certificate");
+ ret = -1;
+ goto exit;
+ }
+
+ mbedtls_x509write_crt_set_subject_key(&cert, subject_key);
+ mbedtls_x509write_crt_set_issuer_key(&cert, issuer_key);
+
+ /*
+ * Setting parameters of signed certificate
+ */
+ ret = mbedtls_x509write_crt_set_subject_name(&cert, cert_opt.subject_name);
+ if (ret != 0)
+ {
+ mbedtls_strerror( ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "Setting subject name in signed certificate failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ ret = mbedtls_x509write_crt_set_issuer_name(&cert, cert_opt.issuer_name);
+ if (ret != 0)
+ {
+ mbedtls_strerror( ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "Setting issuer name in signed certificate failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ ret = mbedtls_x509write_crt_set_serial(&cert, &serial);
+ if (ret != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "Setting serial number in signed certificate failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ ret = mbedtls_x509write_crt_set_validity(&cert, cert_opt.not_before,
+ cert_opt.not_after);
+ if (ret != 0)
+ {
+ mbedtls_strerror( ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "Setting validity in signed certificate failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Setting the basicConstraints extension for certificate
+ */
+ ret = mbedtls_x509write_crt_set_basic_constraints(&cert, cert_opt.is_ca,
+ cert_opt.max_pathlen);
+ if (ret != 0)
+ {
+ mbedtls_strerror( ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR, "Setting the basicConstraints extension "
+ "in signed certificate failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+#if defined(MBEDTLS_SHA1_C)
+ /* Setting the subjectKeyIdentifier extension for certificate */
+ ret = mbedtls_x509write_crt_set_subject_key_identifier(&cert);
+ if (ret != 0)
+ {
+ mbedtls_strerror( ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR, "mbedtls_x509write_crt_set_subject_key_"
+ "identifier failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+
+ /* Setting the authorityKeyIdentifier extension for certificate */
+ ret = mbedtls_x509write_crt_set_authority_key_identifier(&cert);
+ if (ret != 0)
+ {
+ mbedtls_strerror( ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR, "mbedtls_x509write_crt_set_authority_key_"
+ "identifier failed: %s", err_buf);
+ ret = -1;
+ goto exit;
+ }
+#endif /* MBEDTLS_SHA1_C */
+
+ /*
+ * Writing certificate into file
+ */
+ ret = write_certificate(&cert, cert_opt.output_file,
+ mbedtls_ctr_drbg_random, &ctr_drbg);
+ if (ret < 0)
+ {
+ log_error(LOG_LEVEL_ERROR, "Writing certificate into file failed");
+ goto exit;
+ }
+
+exit:
+ /*
+ * Freeing used structures
+ */
+ mbedtls_x509write_crt_free(&cert);
+ mbedtls_pk_free(&loaded_subject_key);
+ mbedtls_pk_free(&loaded_issuer_key);
+ mbedtls_mpi_free(&serial);
+ mbedtls_x509_crt_free(&issuer_cert);
+
+ freez(cert_opt.subject_key);
+ freez(cert_opt.output_file);
+ freez(key_buf);
+
+ return ret;
+}
+
+
+/*********************************************************************
+ *
+ * Function : make_certs_path
+ *
+ * Description : Creates path to file from three pieces. This fuction
+ * takes parameters and puts them in one new mallocated
+ * char * in correct order. Returned variable must be freed
+ * by caller. This function is mainly used for creating
+ * paths of certificates and keys files.
+ *
+ * Parameters :
+ * 1 : conf_dir = Name/path of directory where is the file.
+ * '.' can be used for current directory.
+ * 2 : file_name = Name of file in conf_dir without suffix.
+ * 3 : suffix = Suffix of given file_name.
+ *
+ * Returns : path => Path was built up successfully
+ * NULL => Path can't be built up
+ *
+ *********************************************************************/
+static char *make_certs_path(const char *conf_dir, const char *file_name,
+ const char *suffix)
+{
+ /* Test if all given parameters are valid */
+ if (conf_dir == NULL || *conf_dir == '\0' || file_name == NULL ||
+ *file_name == '\0' || suffix == NULL || *suffix == '\0')
+ {
+ log_error(LOG_LEVEL_ERROR,
+ "make_certs_path failed: bad input parameters");
+ return NULL;
+ }
+
+ char *path = NULL;
+ size_t path_size = strlen(conf_dir)
+ + strlen(file_name) + strlen(suffix) + 2;
+
+ /* Setting delimiter and editing path length */
+#if defined(_WIN32) || defined(__OS2__)
+ char delim[] = "\\";
+ path_size += 1;
+#else /* ifndef _WIN32 || __OS2__ */
+ char delim[] = "/";
+#endif /* ifndef _WIN32 || __OS2__ */
+
+ /*
+ * Building up path from many parts
+ */
+#if defined(unix)
+ if (*conf_dir != '/' && basedir && *basedir)
+ {
+ /*
+ * Replacing conf_dir with basedir. This new variable contains
+ * absolute path to cwd.
+ */
+ path_size += strlen(basedir) + 2;
+ path = (char *)malloc(path_size);
+ if (path == NULL)
+ {
+ log_error(LOG_LEVEL_ERROR, "make_certs_path failed: malloc fail");
+ return NULL;
+ }
+ memset(path, 0, path_size);
+
+ strlcpy(path, basedir, path_size);
+ strlcat(path, delim, path_size);
+ strlcat(path, conf_dir, path_size);
+ strlcat(path, delim, path_size);
+ strlcat(path, file_name, path_size);
+ strlcat(path, suffix, path_size);
+ }
+ else
+#endif /* defined unix */
+ {
+ path = (char *)malloc(path_size);
+ if (path == NULL)
+ {
+ log_error(LOG_LEVEL_ERROR, "make_certs_path failed: malloc fail");
+ return NULL;
+ }
+ memset(path, 0, path_size);
+
+ strlcpy(path, conf_dir, path_size);
+ strlcat(path, delim, path_size);
+ strlcat(path, file_name, path_size);
+ strlcat(path, suffix, path_size);
+ }
+
+ return path;
+}
+
+
+/*********************************************************************
+ *
+ * Function : get_certificate_mutex_id
+ *
+ * Description : Computes mutex id from host name hash. This hash must
+ * be already saved in csp structure
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : Mutex id for given host name
+ *
+ *********************************************************************/
+static unsigned int get_certificate_mutex_id(struct client_state *csp) {
+#ifdef LIMIT_MUTEX_NUMBER
+ return (unsigned int)(csp->http->hash_of_host[0] % 32);
+#else
+ return (unsigned int)(csp->http->hash_of_host[1]
+ + 256 * (int)csp->http->hash_of_host[0]);
+#endif /* LIMIT_MUTEX_NUMBER */
+}
+
+
+/*********************************************************************
+ *
+ * Function : get_certificate_serial
+ *
+ * Description : Computes serial number for new certificate from host
+ * name hash. This hash must be already saved in csp
+ * structure.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : Serial number for new certificate
+ *
+ *********************************************************************/
+static unsigned long get_certificate_serial(struct client_state *csp) {
+ unsigned long exp = 1;
+ unsigned long serial = 0;
+
+ int i = CERT_SERIAL_NUM_LENGTH;
+ /* Length of hash is 16 bytes, we must avoid to read next chars */
+ if (i > 16)
+ {
+ i = 16;
+ }
+ if (i < 2)
+ {
+ i = 2;
+ }
+
+ for (; i >= 0; i--)
+ {
+ serial += exp * (unsigned)csp->http->hash_of_host[i];
+ exp *= 256;
+ }
+ return serial;
+}
+
+
+/*********************************************************************
+ *
+ * Function : ssl_send_certificate_error
+ *
+ * Description : Sends info about invalid server certificate to client.
+ * Sent message is including all trusted chain certificates,
+ * that can be downloaded in web browser.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : N/A
+ *
+ *********************************************************************/
+extern void ssl_send_certificate_error(struct client_state *csp)
+{
+ size_t message_len = 0;
+ int ret = 0;
+ struct certs_chain *cert = NULL;
+
+ /* Header of message with certificate informations */
+ const char message_begin[] =
+ "HTTP/1.1 200 OK\r\n"
+ "Content-Type: text/html\r\n"
+ "Connection: close\r\n\r\n"
+ "<html><body><h1>Invalid server certificate</h1><p>Reason: ";
+ const char message_end[] = "</body></html>\r\n\r\n";
+ char reason[INVALID_CERT_INFO_BUF_SIZE];
+ memset(reason, 0, sizeof(reason));
+
+ /* Get verification message from verification return code */
+ mbedtls_x509_crt_verify_info(reason, sizeof(reason), " ",
+ csp->server_cert_verification_result);
+
+ /*
+ * Computing total length of message with all certificates inside
+ */
+ message_len = strlen(message_begin) + strlen(message_end)
+ + strlen(reason) + strlen("</p>") + 1;
+
+ cert = &(csp->server_certs_chain);
+ while (cert->next != NULL)
+ {
+ size_t base64_len = 4 * ((strlen(cert->file_buf) + 2) / 3) + 1;
+
+ message_len += strlen(cert->text_buf) + strlen("<pre></pre>\n")
+ + base64_len + strlen("<a href=\"data:application"
+ "/x-x509-ca-cert;base64,\">Download certificate</a>");
+ cert = cert->next;
+ }
+
+ /*
+ * Joining all blocks in one long message
+ */
+ char message[message_len];
+ memset(message, 0, message_len);
+
+ strlcpy(message, message_begin, message_len);
+ strlcat(message, reason , message_len);
+ strlcat(message, "</p>" , message_len);
+
+ cert = &(csp->server_certs_chain);
+ while (cert->next != NULL)
+ {
+ size_t olen = 0;
+ size_t base64_len = 4 * ((strlen(cert->file_buf) + 2) / 3) + 1; /* +1 for terminating null*/
+ char base64_buf[base64_len];
+ memset(base64_buf, 0, base64_len);
+
+ /* Encoding certificate into base64 code */
+ ret = mbedtls_base64_encode((unsigned char*)base64_buf,
+ base64_len, &olen, (const unsigned char*)cert->file_buf,
+ strlen(cert->file_buf));
+ if (ret != 0)
+ {
+ log_error(LOG_LEVEL_ERROR,
+ "Encoding to base64 failed, buffer is to small");
+ }
+
+ strlcat(message, "<pre>", message_len);
+ strlcat(message, cert->text_buf, message_len);
+ strlcat(message, "</pre>\n", message_len);
+
+ if (ret == 0)
+ {
+ strlcat(message, "<a href=\"data:application/x-x509-ca-cert;base64,",
+ message_len);
+ strlcat(message, base64_buf, message_len);
+ strlcat(message, "\">Download certificate</a>", message_len);
+ }
+
+ cert = cert->next;
+ }
+ strlcat(message, message_end, message_len);
+
+ /*
+ * Sending final message to client
+ */
+ ssl_send_data(&(csp->mbedtls_client_attr.ssl),
+ (const unsigned char *)message, strlen(message));
+ /*
+ * Waiting before closing connection. Some browsers doesn't show received
+ * message if there isn't this delay.
+ */
+ sleep(1);
+
+ free_certificate_chain(csp);
+}
+
+
+/*********************************************************************
+ *
+ * Function : ssl_verify_callback
+ *
+ * Description : This is a callback function for certificate verification.
+ * It's called for all certificates in server certificate
+ * trusted chain and it's preparing information about this
+ * certificates. Prepared informations can be used to inform
+ * user about invalid certificates.
+ *
+ * Parameters :
+ * 1 : csp_void = Current client state (buffers, headers, etc...)
+ * 2 : crt = certificate from trusted chain
+ * 3 : depth = depth in trusted chain
+ * 4 : flags = certificate flags
+ *
+ * Returns : 0 on success and negative value on error
+ *
+ *********************************************************************/
+static int ssl_verify_callback(void *csp_void, mbedtls_x509_crt *crt,
+ int depth, uint32_t *flags)
+{
+ struct client_state *csp = (struct client_state *)csp_void;
+ struct certs_chain *last = &(csp->server_certs_chain);
+ size_t olen = 0;
+ int ret = 0;
+
+ /*
+ * Searching for last item in certificates linked list
+ */
+ while (last->next != NULL)
+ {
+ last = last->next;
+ }
+
+ /*
+ * Preparing next item in linked list for next certificate
+ * If malloc fails, we are continuing without this certificate
+ */
+ last->next = (struct certs_chain *)malloc(sizeof(struct certs_chain));
+ if (last->next != NULL)
+ {
+ last->next->next = NULL;
+ memset(last->next->text_buf, 0, sizeof(last->next->text_buf));
+ memset(last->next->file_buf, 0, sizeof(last->next->file_buf));
+
+ /*
+ * Saving certificate file into buffer
+ */
+ if ((ret = mbedtls_pem_write_buffer(PEM_BEGIN_CRT, PEM_END_CRT,
+ crt->raw.p, crt->raw.len, (unsigned char *)last->file_buf,
+ sizeof(last->file_buf)-1, &olen)) != 0)
+ {
+ return(ret);
+ }
+
+ /*
+ * Saving certificate information into buffer
+ */
+ mbedtls_x509_crt_info(last->text_buf, sizeof(last->text_buf) - 1,
+ CERT_INFO_PREFIX, crt);
+ }
+ else
+ {
+ log_error(LOG_LEVEL_ERROR,
+ "Malloc memory for server certificate informations failed");
+ return -1;
+ }
+
+ return 0;
+}
+
+
+/*********************************************************************
+ *
+ * Function : free_certificate_chain
+ *
+ * Description : Frees certificates linked list. This linked list is
+ * used to save informations about certificates in
+ * trusted chain.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : N/A
+ *
+ *********************************************************************/
+static void free_certificate_chain(struct client_state *csp)
+{
+ struct certs_chain *cert = csp->server_certs_chain.next;
+
+ /* Cleaning buffers */
+ memset(csp->server_certs_chain.text_buf, 0,
+ sizeof(csp->server_certs_chain.text_buf));
+ memset(csp->server_certs_chain.text_buf, 0,
+ sizeof(csp->server_certs_chain.file_buf));
+ csp->server_certs_chain.next = NULL;
+
+ /* Freeing memory in whole linked list */
+ if (cert != NULL)
+ {
+ do
+ {
+ struct certs_chain *cert_for_free = cert;
+ cert = cert->next;
+ freez(cert_for_free);
+ } while (cert != NULL);
+ }
+}
+
+
+/*********************************************************************
+*
+* Function : file_exists
+*
+* Description : Tests if file exists and is readable.
+*
+* Parameters :
+* 1 : path = Path to tested file.
+*
+* Returns : 1 => File exists and is readable.
+* 0 => File doesn't exist or is not readable.
+*
+*********************************************************************/
+static int file_exists(const char *path)
+{
+ FILE *f;
+ if ((f = fopen(path, "r")) != NULL)
+ {
+ fclose(f);
+ return 1;
+ }
+
+ return 0;
+}
+
+
+/*********************************************************************
+*
+* Function : host_to_hash
+*
+* Description : Creates MD5 hash from host name. Host name is loaded
+* from structure csp and saved again into it.
+*
+* Parameters :
+* 1 : csp = Current client state (buffers, headers, etc...)
+*
+* Returns : 1 => Error while creating hash
+* 0 => Hash created successfully
+*
+*********************************************************************/
+static int host_to_hash(struct client_state * csp)
+{
+ int ret = 0;
+
+#if !defined(MBEDTLS_MD5_C)
+ log_error(LOG_LEVEL_ERROR, "MBEDTLS_MD5_C is not defined. Can't create"
+ "MD5 hash for certificate and key name.");
+ return -1;
+#else
+ memset(csp->http->hash_of_host, 0, sizeof(csp->http->hash_of_host));
+ mbedtls_md5((unsigned char *)csp->http->host, strlen(csp->http->host),
+ csp->http->hash_of_host);
+
+ /* Converting hash into string with hex */
+ size_t i = 0;
+ for (; i < 16; i++)
+ {
+ if ((ret = sprintf((char *)csp->http->hash_of_host_hex + 2 * i, "%02x",
+ csp->http->hash_of_host[i])) < 0)
+ {
+ log_error(LOG_LEVEL_ERROR, "Sprintf return value: %d", ret);
+ return -1;
+ }
+ }
+
+ return 0;
+#endif /* MBEDTLS_MD5_C */
+}
+
+
+/*********************************************************************
+ *
+ * Function : tunnel_established_successfully
+ *
+ * Description : Check if parent proxy server response contains
+ * informations about successfully created connection with
+ * destination server. (HTTP/... 2xx ...)
+ *
+ * Parameters :
+ * 1 : server_response = Buffer with parent proxy server response
+ * 2 : response_len = Length of server_response
+ *
+ * Returns : 1 => Connection created successfully
+ * 0 => Connection wasn't created successfully
+ *
+ *********************************************************************/
+extern int tunnel_established_successfully(const char *server_response,
+ unsigned int response_len)
+{
+ unsigned int pos = 0;
+
+ if (server_response == NULL)
+ {
+ return 0;
+ }
+
+ /* Tests if "HTTP/" string is at the begin of received response */
+ if (strncmp(server_response, "HTTP/", 5) != 0)
+ {
+ return 0;
+ }
+
+ for (pos = 0; pos < response_len; pos++)
+ {
+ if (server_response[pos] == ' ')
+ {
+ break;
+ }
+ }
+
+ /*
+ * response_len -3 because of buffer end, response structure and 200 code.
+ * There must be at least 3 chars after space.
+ * End of buffer: ... 2xx'\0'
+ * pos = |
+ */
+ if (pos >= (response_len - 3))
+ {
+ return 0;
+ }
+
+ /* Test HTTP status code */
+ if (server_response[pos + 1] != '2')
+ {
+ return 0;
+ }
+
+ return 1;
+}
+
+
+/*********************************************************************
+ *
+ * Function : seed_rng
+ *
+ * Description : Seeding the RNG for all SSL uses
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : -1 => RNG wasn't seed successfully
+ * 0 => RNG is seeded successfully
+ *
+ *********************************************************************/
+static int seed_rng(struct client_state *csp)
+{
+ int ret = 0;
+ char err_buf[ERROR_BUF_SIZE];
+
+ memset(err_buf, 0, sizeof(err_buf));
+
+ if (rng_seeded == 0)
+ {
+ privoxy_mutex_lock(&rng_mutex);
+ if (rng_seeded == 0)
+ {
+ mbedtls_ctr_drbg_init(&ctr_drbg);
+ mbedtls_entropy_init(&entropy);
+ ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func,
+ &entropy, NULL, 0);
+ if (ret != 0)
+ {
+ mbedtls_strerror(ret, err_buf, sizeof(err_buf));
+ log_error(LOG_LEVEL_ERROR,
+ "mbedtls_ctr_drbg_seed failed: %s", err_buf);
+ privoxy_mutex_unlock(&rng_mutex);
+ return -1;
+ }
+ rng_seeded = 1;
+ }
+ privoxy_mutex_unlock(&rng_mutex);
+ }
+ return 0;
+}