X-Git-Url: https://ruderich.org/simon/gitweb/?a=blobdiff_plain;f=src%2Fconnection.c;h=ac3bc21cb5db457f0553566e23cda32a690d4750;hb=506cbe74344581542c5673b69b84363e72d0a3a0;hp=37f255013201a7bcc120da1453d71b6a5e3bb866;hpb=00c3bd4d3ce76d47440473aac3a850c2f837ebb8;p=tlsproxy%2Ftlsproxy.git diff --git a/src/connection.c b/src/connection.c index 37f2550..ac3bc21 100644 --- a/src/connection.c +++ b/src/connection.c @@ -1,7 +1,7 @@ /* * Handle connections. * - * Copyright (C) 2011 Simon Ruderich + * Copyright (C) 2011-2013 Simon Ruderich * * 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 @@ -19,6 +19,7 @@ #include "tlsproxy.h" #include "connection.h" +#include "verify.h" /* close() */ #include @@ -28,48 +29,57 @@ #include /* errno */ #include -/* va_*() */ -#include -/* pthread_*() */ -#include -/* Maximum line of a HTTP request line. Longer request lines are aborted with - * an error. The standard doesn't specify a maximum line length but this - * should be a good limit to make processing simpler. */ +/* Maximum length of a HTTP request line. Longer request lines are aborted + * with an error. The standard doesn't specify a maximum line length but this + * should be a good limit to make processing simpler. As HTTPS is used this + * doesn't limit long GET requests. */ #define MAX_REQUEST_LINE 4096 -/* Helper macro for LOG/LOG_PERROR. Print file/line number if compiled with - * debug output. */ -#ifdef DEBUG -#define LOG_PRINT_LOCATION fprintf(stdout, "%s:%-3d ", __FILE__, __LINE__); -#else -#define LOG_PRINT_LOCATION -#endif -/* Call log_message() and print current file and line number. */ -#define LOG \ - LOG_PRINT_LOCATION \ - log_message -/* perror() replacement with debug level support. */ -#define LOG_PERROR(level, message) \ - LOG_PRINT_LOCATION \ - log_message(level, "%s: %s", message, strerror(errno)) - +/* Format string used to send HTTP/1.0 error responses to the client. + * + * %s is used 4 times, first three are the error code (no %n$s!), the last is + * the message. */ +#define HTTP_RESPONSE_FORMAT "HTTP/1.0 %s\r\n\ +Content-Type: text/html; charset=US-ASCII\r\n\ +\r\n\ +\n\ +\n\ +%s\n\ +\n\ +

%s

\n\ +

\n\ +\n\ +\n" + + +static int initialize_tls_session_client(int peer_socket, + const char *hostname, + gnutls_session_t *session, + gnutls_certificate_credentials_t *x509_cred); +static int initialize_tls_session_server(int peer_socket, + gnutls_session_t *session, + gnutls_certificate_credentials_t *x509_cred); static int read_http_request(FILE *client_fd, char *request, size_t length); static void send_bad_request(FILE *client_fd); static void send_forwarding_failure(FILE *client_fd); +static void tls_send_invalid_cert_message(gnutls_session_t session); static void transfer_data(int client, int server); static int read_from_write_to(int from, int to); +static void transfer_data_tls(int client, int server, + gnutls_session_t client_session, + gnutls_session_t server_session); +static int read_from_write_to_tls(gnutls_session_t from, gnutls_session_t to, + size_t buffer_size); static int connect_to_host(const char *hostname, const char *port); static int parse_request(const char *buffer, char *host, char *port, int *version_minor); -static void log_message(int level, const char *format, ...); - void handle_connection(int client_socket) { int server_socket; @@ -79,14 +89,33 @@ void handle_connection(int client_socket) { char host[MAX_REQUEST_LINE]; char port[5 + 1]; - int version_minor; + int version_minor; /* HTTP/1.x */ int result; + /* client_x509_cred is used when talking to the client (acting as a TSL + * server), server_x509_cred is used when talking to the server (acting as + * a TSL client). */ + gnutls_certificate_credentials_t client_x509_cred, server_x509_cred; + + gnutls_session_t client_session, server_session; + /* initialize_tls_session_*() called? - used for goto out */ + int client_session_init, server_session_init; + /* gnutls_handshake() called? - used for goto out */ + int client_session_started, server_session_started; + /* Validation failed? If yes we need to send the special "invalid" + * certificate. */ + int validation_failed; + LOG(LOG_DEBUG, "new connection"); server_socket = -1; client_fd = NULL; server_fd = NULL; + client_session_init = 0; + server_session_init = 0; + client_session_started = 0; + server_session_started = 0; + validation_failed = 0; client_fd = fdopen(client_socket, "a+"); if (NULL == client_fd) { @@ -166,15 +195,139 @@ void handle_connection(int client_socket) { LOG(LOG_DEBUG, "connection to server established"); + /* If the -u option is used and we don't know this hostname's server + * certificate then just pass through the connection and let the client + * verify the server certificate. */ + if (global_passthrough_unknown) { + char path[TLSPROXY_MAX_PATH_LENGTH]; + FILE *file = NULL; + + if (-2 == server_certificate_file(&file, host, path, sizeof(path))) { + /* We've established a connection, tell the client. */ + fprintf(client_fd, "HTTP/1.0 200 Connection established\r\n"); + fprintf(client_fd, "\r\n"); + fflush(client_fd); + + LOG(LOG_DEBUG, "transferring data"); + + /* Proxy data between client and server until one side is done + * (EOF or error). */ + transfer_data(client_socket, server_socket); + + LOG(LOG_DEBUG, "finished transferring data"); + + goto out; + } + /* server_certificate_file() may have opened the file, close it. */ + if (NULL != file) { + fclose(file); + } + } + + /* Initialize TLS client credentials to talk to the server. */ + result = initialize_tls_session_server(server_socket, &server_session, + &server_x509_cred); + if (0 != result) { + LOG(LOG_WARNING, "initialize_tls_session_server() failed"); + send_forwarding_failure(client_fd); + goto out; + } + server_session_init = 1; + + LOG(LOG_DEBUG, "starting server TLS handshake"); + + /* Try to establish TLS handshake between us and server. */ + result = gnutls_handshake(server_session); + if (GNUTLS_E_SUCCESS != result) { + LOG(LOG_WARNING, "server TLS handshake failed: %s", + gnutls_strerror(result)); + send_forwarding_failure(client_fd); + goto out; + } + server_session_started = 1; + + LOG(LOG_DEBUG, "server TLS handshake finished"); + + /* Make sure the server certificate is valid and known. */ + if (0 != verify_tls_connection(server_session, host)) { + LOG(LOG_ERROR, "server certificate validation failed!"); + /* We send the error message over our TLS connection to the client, + * but with an invalid certificate. No data is transfered from/to the + * target server. */ + validation_failed = 1; + } + + /* Initialize TLS server credentials to talk to the client. */ + result = initialize_tls_session_client(client_socket, + /* use a special host if the server + * certificate was invalid */ + (validation_failed) ? "invalid" + : host, + &client_session, + &client_x509_cred); + if (0 != result) { + LOG(LOG_WARNING, "initialize_tls_session_client() failed"); + send_forwarding_failure(client_fd); + goto out; + } + client_session_init = 1; + /* We've established a connection, tell the client. */ fprintf(client_fd, "HTTP/1.0 200 Connection established\r\n"); fprintf(client_fd, "\r\n"); fflush(client_fd); - /* And transfer all data between client and server transparently. */ - transfer_data(client_socket, server_socket); + LOG(LOG_DEBUG, "starting client TLS handshake"); + + /* Try to establish TLS handshake between client and us. */ + result = gnutls_handshake(client_session); + if (GNUTLS_E_SUCCESS != result) { + LOG(LOG_WARNING, "client TLS handshake failed: %s", + gnutls_strerror(result)); + send_forwarding_failure(client_fd); + goto out; + } + client_session_started = 1; + + LOG(LOG_DEBUG, "client TLS handshake finished"); + + /* Tell the client that the verification failed. Shouldn't be necessary as + * the client should terminate the connection because he received the + * invalid certificate but better be sure. */ + if (validation_failed) { + tls_send_invalid_cert_message(client_session); + goto out; + } + + LOG(LOG_DEBUG, "transferring TLS data"); + + /* Proxy data between client and server until one side is done (EOF or + * error). */ + transfer_data_tls(client_socket, server_socket, + client_session, server_session); + + LOG(LOG_DEBUG, "finished transferring TLS data"); out: + /* Close TLS sessions if necessary. Use GNUTLS_SHUT_RDWR so the data is + * reliable transmitted. */ + if (0 != server_session_started) { + gnutls_bye(server_session, GNUTLS_SHUT_RDWR); + } + if (0 != client_session_started) { + gnutls_bye(client_session, GNUTLS_SHUT_RDWR); + } + if (0 != server_session_init) { + gnutls_deinit(server_session); + gnutls_certificate_free_credentials(server_x509_cred); + } + if (0 != client_session_init) { + gnutls_deinit(client_session); + gnutls_certificate_free_cas(client_x509_cred); + gnutls_certificate_free_keys(client_x509_cred); + gnutls_certificate_free_credentials(client_x509_cred); + } + /* Close connection to server/proxy. */ if (NULL != server_fd) { fclose(server_fd); @@ -193,6 +346,156 @@ out: LOG(LOG_DEBUG, "connection finished"); } + +static int initialize_tls_session_client(int peer_socket, + const char *hostname, + gnutls_session_t *session, + gnutls_certificate_credentials_t *x509_cred) { + int result; + int use_invalid_cert; + char path[TLSPROXY_MAX_PATH_LENGTH]; + + /* The "invalid" hostname is special. If it's used we send an invalid + * certificate to let the client know something is wrong. */ + use_invalid_cert = (0 == strcmp(hostname, "invalid")); + + if (0 != proxy_certificate_path(hostname, path, sizeof(path))) { + LOG(LOG_ERROR, + "initialize_tls_session_client(): \ +failed to get proxy certificate path"); + return -1; + } + + result = gnutls_certificate_allocate_credentials(x509_cred); + if (GNUTLS_E_SUCCESS != result) { + LOG(LOG_ERROR, + "initialize_tls_session_client(): \ +gnutls_certificate_allocate_credentials(): %s", + gnutls_strerror(result)); + return -1; + } + + /* Load proxy CA file, this CA "list" is send to the client. */ + if (!use_invalid_cert) { + result = gnutls_certificate_set_x509_trust_file(*x509_cred, + PROXY_CA_FILE, + GNUTLS_X509_FMT_PEM); + if (0 >= result) { + LOG(LOG_ERROR, + "initialize_tls_session_client(): can't read CA file: '%s'", + PROXY_CA_FILE); + gnutls_certificate_free_credentials(*x509_cred); + return -1; + } + } + /* If the invalid hostname was specified do nothing, we use a self-signed + * certificate in this case. */ + + /* And certificate for this website and proxy's private key. */ + if (!use_invalid_cert) { + result = gnutls_certificate_set_x509_key_file(*x509_cred, + path, PROXY_KEY_FILE, + GNUTLS_X509_FMT_PEM); + /* If the invalid hostname was specified load our special "invalid" + * certificate. */ + } else { + result = gnutls_certificate_set_x509_key_file(*x509_cred, + PROXY_INVALID_CERT_FILE, + PROXY_KEY_FILE, + GNUTLS_X509_FMT_PEM); + } + if (GNUTLS_E_SUCCESS != result) { + LOG(LOG_ERROR, + "initialize_tls_session_client(): \ +can't read server certificate ('%s') or key file ('%s'): %s", + path, PROXY_KEY_FILE, gnutls_strerror(result)); + gnutls_certificate_free_credentials(*x509_cred); + /* Could be a missing certificate. */ + return -2; + } + + gnutls_certificate_set_dh_params(*x509_cred, global_tls_dh_params); + + result = gnutls_init(session, GNUTLS_SERVER); + if (GNUTLS_E_SUCCESS != result) { + LOG(LOG_ERROR, + "initialize_tls_session_client(): gnutls_init(): %s", + gnutls_strerror(result)); + gnutls_certificate_free_credentials(*x509_cred); + return -1; + } + result = gnutls_priority_set(*session, global_tls_priority_cache); + if (GNUTLS_E_SUCCESS != result) { + LOG(LOG_ERROR, + "initialize_tls_session_client(): gnutls_priority_set(): %s", + gnutls_strerror(result)); + gnutls_deinit(*session); + gnutls_certificate_free_credentials(*x509_cred); + return -1; + } + result = gnutls_credentials_set(*session, + GNUTLS_CRD_CERTIFICATE, *x509_cred); + if (GNUTLS_E_SUCCESS != result) { + LOG(LOG_ERROR, + "initialize_tls_session_client(): gnutls_credentials_set(): %s", + gnutls_strerror(result)); + gnutls_deinit(*session); + gnutls_certificate_free_credentials(*x509_cred); + return -1; + } + + gnutls_transport_set_ptr(*session, (gnutls_transport_ptr_t)peer_socket); + + return 0; +} +static int initialize_tls_session_server(int peer_socket, + gnutls_session_t *session, + gnutls_certificate_credentials_t *x509_cred) { + int result; + + result = gnutls_certificate_allocate_credentials(x509_cred); + if (GNUTLS_E_SUCCESS != result) { + LOG(LOG_ERROR, + "initialize_tls_session_server(): \ +gnutls_certificate_allocate_credentials(): %s", + gnutls_strerror(result)); + return -1; + } + + result = gnutls_init(session, GNUTLS_CLIENT); + if (GNUTLS_E_SUCCESS != result) { + LOG(LOG_ERROR, + "initialize_tls_session_server(): gnutls_init(): %s", + gnutls_strerror(result)); + gnutls_certificate_free_credentials(*x509_cred); + return -1; + } + result = gnutls_priority_set(*session, global_tls_priority_cache); + if (GNUTLS_E_SUCCESS != result) { + LOG(LOG_ERROR, + "initialize_tls_session_server(): gnutls_priority_set(): %s", + gnutls_strerror(result)); + gnutls_deinit(*session); + gnutls_certificate_free_credentials(*x509_cred); + return -1; + } + result = gnutls_credentials_set(*session, + GNUTLS_CRD_CERTIFICATE, *x509_cred); + if (GNUTLS_E_SUCCESS != result) { + LOG(LOG_ERROR, + "initialize_tls_session_server(): gnutls_credentials_set(): %s", + gnutls_strerror(result)); + gnutls_deinit(*session); + gnutls_certificate_free_credentials(*x509_cred); + return -1; + } + + gnutls_transport_set_ptr(*session, (gnutls_transport_ptr_t)peer_socket); + + return 0; +} + + /* Read HTTP request line and headers (ignored). * * On success 0 is returned, -1 on client error, -2 on unexpected EOF. @@ -209,7 +512,7 @@ static int read_http_request(FILE *client_fd, char *request, size_t length) { return -2; } - while (NULL != fgets(buffer, MAX_REQUEST_LINE, client_fd)) { + while (NULL != fgets(buffer, sizeof(buffer), client_fd)) { /* End of header. */ if (0 == strcmp(buffer, "\n") || 0 == strcmp(buffer, "\r\n")) { break; @@ -224,12 +527,52 @@ static int read_http_request(FILE *client_fd, char *request, size_t length) { } static void send_bad_request(FILE *client_fd) { - fprintf(client_fd, "HTTP/1.0 400 Bad Request\r\n"); - fprintf(client_fd, "\r\n"); +#define RESPONSE_ERROR "400 Bad Request" +#define RESPONSE_MSG "Your browser sent an invalid request." + fprintf(client_fd, HTTP_RESPONSE_FORMAT, + RESPONSE_ERROR, RESPONSE_ERROR, RESPONSE_ERROR, + RESPONSE_MSG); +#undef RESPONSE_ERROR +#undef RESPONSE_MSG } static void send_forwarding_failure(FILE *client_fd) { - fprintf(client_fd, "HTTP/1.0 503 Forwarding failure\r\n"); - fprintf(client_fd, "\r\n"); +#define RESPONSE_ERROR "503 Forwarding failure" +#define RESPONSE_MSG "Failed to connect to server, check logs." + fprintf(client_fd, HTTP_RESPONSE_FORMAT, + RESPONSE_ERROR, RESPONSE_ERROR, RESPONSE_ERROR, + RESPONSE_MSG); +#undef RESPONSE_ERROR +#undef RESPONSE_MSG +} +static void tls_send_invalid_cert_message(gnutls_session_t session) { +#define RESPONSE_ERROR "500 Internal Server Error" +#define RESPONSE_MSG "Server certificate validation failed, check logs." + + int result; + char buffer[sizeof(HTTP_RESPONSE_FORMAT) - 1 /* '\0' */ + - 4 * 2 /* four %s */ + + (sizeof(RESPONSE_ERROR) - 1 /* '\0' */) * 3 + + sizeof(RESPONSE_MSG) - 1 /* '\0' */ + + 1 /* '\0' */]; + + result = snprintf(buffer, sizeof(buffer), + HTTP_RESPONSE_FORMAT, + RESPONSE_ERROR, RESPONSE_ERROR, RESPONSE_ERROR, + RESPONSE_MSG); + if (result < 0) { + LOG_PERROR(LOG_ERROR, + "tls_send_invalid_cert_message(): snprintf failed"); + return; + } else if ((size_t)result >= sizeof(buffer)) { + LOG(LOG_ERROR, + "tls_send_invalid_cert_message(): snprintf buffer too short"); + return; + } + + gnutls_record_send(session, buffer, sizeof(buffer) - 1); + /* don't send trailing '\0' */ +#undef RESPONSE_ERROR +#undef RESPONSE_MSG } @@ -284,6 +627,8 @@ static int read_from_write_to(int from, int to) { ssize_t size_written; char buffer[4096]; + LOG(LOG_DEBUG, "read_from_write_to(): %d -> %d", from, to); + size_read = read(from, buffer, sizeof(buffer)); if (0 > size_read) { LOG_PERROR(LOG_WARNING, "read_from_write_to(): read()"); @@ -308,6 +653,104 @@ static int read_from_write_to(int from, int to) { return 0; } +/* Transfer data between client and server TLS connection until one closes the + * connection. */ +static void transfer_data_tls(int client, int server, + gnutls_session_t client_session, + gnutls_session_t server_session) { + size_t buffer_size; + + struct pollfd fds[2]; + fds[0].fd = client; + fds[0].events = POLLIN | POLLPRI | POLLHUP | POLLERR; + fds[0].revents = 0; + fds[1].fd = server; + fds[1].events = POLLIN | POLLPRI | POLLHUP | POLLERR; + fds[1].revents = 0; + + /* Get maximum possible buffer size. */ + buffer_size = gnutls_record_get_max_size(client_session); + if (buffer_size > gnutls_record_get_max_size(server_session)) { + buffer_size = gnutls_record_get_max_size(server_session); + } + LOG(LOG_DEBUG, "transfer_data_tls(): suggested buffer size: %ld", + (long int)buffer_size); + + for (;;) { + int result = poll(fds, 2, -1 /* no timeout */); + if (result < 0) { + LOG_PERROR(LOG_ERROR, "transfer_data(): poll()"); + return; + } + + /* Data available from client. */ + if (fds[0].revents & POLLIN || fds[0].revents & POLLPRI) { + if (0 != read_from_write_to_tls(client_session, server_session, + buffer_size)) { + /* EOF (or other error) */ + break; + } + } + /* Data available from server. */ + if (fds[1].revents & POLLIN || fds[1].revents & POLLPRI) { + if (0 != read_from_write_to_tls(server_session, client_session, + buffer_size)) { + /* EOF (or other error) */ + break; + } + } + + /* Client closed connection. */ + if (fds[0].revents & POLLERR || fds[0].revents & POLLHUP) { + break; + } + /* Server closed connection. */ + if (fds[1].revents & POLLERR || fds[1].revents & POLLHUP) { + break; + } + } +} + +/* Read available data from session from and write to session to. */ +static int read_from_write_to_tls(gnutls_session_t from, + gnutls_session_t to, + size_t buffer_size) { + ssize_t size_read; + ssize_t size_written; + char buffer[16384]; + + if (buffer_size > sizeof(buffer)) { + buffer_size = sizeof(buffer); + } + LOG(LOG_DEBUG, "read_from_write_to_tls(): used buffer size: %ld", + (long int)buffer_size); + + size_read = gnutls_record_recv(from, buffer, buffer_size); + if (0 > size_read) { + LOG(LOG_WARNING, "read_from_write_to_tls(): gnutls_record_recv(): %s", + gnutls_strerror((int)size_read)); + return -1; + } + /* EOF */ + if (0 == size_read) { + return -1; + } + + size_written = gnutls_record_send(to, buffer, (size_t)size_read); + if (0 > size_written) { + LOG(LOG_WARNING, "read_from_write_to_tls(): gnutls_record_send(): %s", + gnutls_strerror((int)size_written)); + return -1; + } + if (size_read != size_written) { + LOG(LOG_ERROR, "read_from_write_to_tls(): only written %ld of %ld bytes!", + (long int)size_written, (long int)size_read); + return -1; + } + + return 0; +} + static int connect_to_host(const char *hostname, const char *port) { struct addrinfo gai_hints; @@ -403,26 +846,3 @@ static int parse_request(const char *request, char *host, char *port, return 0; } - - -static void log_message(int level, const char *format, ...) { - va_list ap; - const char *level_string; - - if (global_log_level < level) { - return; - } - - switch (level) { - case LOG_ERROR: level_string = "ERROR"; break; - case LOG_WARNING: level_string = "WARN "; break; - case LOG_DEBUG: level_string = "DEBUG"; break; - default: level_string = "UNKNOWN"; - } - - va_start(ap, format); - fprintf(stdout, "[%s] [%d] ", level_string, (int)pthread_self()); - vfprintf(stdout, format, ap); - fprintf(stdout, "\n"); - va_end(ap); -}