X-Git-Url: https://ruderich.org/simon/gitweb/?a=blobdiff_plain;f=src%2Fconnection.c;h=e4b0b29f1b1575dcefb32518c58eb9ef43f3357e;hb=118d7d263672c587a1e4268dbf35df3f913f4aeb;hp=7ea6eb24a7573dd14d5d21facf89a06dc2546c9d;hpb=8db64b0eebeaa80e46b2df40b91af741e533e7bc;p=tlsproxy%2Ftlsproxy.git diff --git a/src/connection.c b/src/connection.c index 7ea6eb2..e4b0b29 100644 --- a/src/connection.c +++ b/src/connection.c @@ -1,7 +1,7 @@ /* * Handle connections. * - * Copyright (C) 2011 Simon Ruderich + * Copyright (C) 2011-2012 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 @@ -30,14 +31,27 @@ #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 -/* Paths to necessary TLS files: the CA and the server key. */ -#define PROXY_CA_FILE "proxy-ca.pem" -#define PROXY_KEY_FILE "proxy-key.pem" +/* 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, @@ -51,15 +65,15 @@ static int initialize_tls_session_server(int peer_socket, 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); -#if 0 static void transfer_data(int client, int server); static int read_from_write_to(int from, int to); -#endif 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); +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); @@ -75,7 +89,7 @@ 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 @@ -88,6 +102,9 @@ void handle_connection(int client_socket) { 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"); @@ -98,6 +115,7 @@ void handle_connection(int client_socket) { 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) { @@ -177,13 +195,74 @@ void handle_connection(int client_socket) { LOG(LOG_DEBUG, "connection to server established"); - /* 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); + /* 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[1024]; + 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, host, + 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) { @@ -193,6 +272,11 @@ void handle_connection(int client_socket) { } 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); + LOG(LOG_DEBUG, "starting client TLS handshake"); /* Try to establish TLS handshake between client and us. */ @@ -207,46 +291,31 @@ void handle_connection(int client_socket) { LOG(LOG_DEBUG, "client TLS handshake finished"); - result = initialize_tls_session_server(server_socket, &server_session, - &server_x509_cred); - /* Initialize TLS client credentials to talk to the server. */ - 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); + /* 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; } - server_session_started = 1; - - LOG(LOG_DEBUG, "server TLS handshake finished, transferring data"); - /* FIXME: verify server's fingerprint */ + LOG(LOG_DEBUG, "transferring TLS data"); - /* Proxy data between client and server until one suite is done (EOF or + /* 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 data"); + LOG(LOG_DEBUG, "finished transferring TLS data"); out: - /* Close TLS sessions if necessary. */ + /* 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_WR); + gnutls_bye(server_session, GNUTLS_SHUT_RDWR); } if (0 != client_session_started) { - gnutls_bye(client_session, GNUTLS_SHUT_WR); + gnutls_bye(client_session, GNUTLS_SHUT_RDWR); } if (0 != server_session_init) { gnutls_deinit(server_session); @@ -283,27 +352,19 @@ static int initialize_tls_session_client(int peer_socket, gnutls_session_t *session, gnutls_certificate_credentials_t *x509_cred) { int result; + int use_invalid_cert; char path[1024]; - /* The server certificate for the given hostname is stored in - * "./certificate-hostname-proxy.pem". */ -#define PATH_FORMAT "./certificate-%s-proxy.pem" - - /* Hostname too long. */ - if (sizeof(path) - strlen(PATH_FORMAT) <= strlen(hostname)) { - LOG(LOG_WARNING, - "initialize_tls_session_client(): hostname too long: '%s'", - hostname); - return -1; - } - /* Try to prevent path traversals in hostnames. */ - if (NULL != strstr(hostname, "..")) { - LOG(LOG_WARNING, - "initialize_tls_session_client(): possible path traversal: '%s'", - hostname); + + /* 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; } - snprintf(path, sizeof(path), PATH_FORMAT, hostname); -#undef PATH_FORMAT result = gnutls_certificate_allocate_credentials(x509_cred); if (GNUTLS_E_SUCCESS != result) { @@ -315,42 +376,61 @@ gnutls_certificate_allocate_credentials(): %s", } /* Load proxy CA file, this CA "list" is send to the client. */ - 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); - return -1; + 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. */ - result = gnutls_certificate_set_x509_key_file(*x509_cred, - path, PROXY_KEY_FILE, - GNUTLS_X509_FMT_PEM); + 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, tls_dh_params); + 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, tls_priority_cache); + 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, @@ -359,6 +439,8 @@ can't read server certificate ('%s') or key file ('%s'): %s", 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; } @@ -385,13 +467,16 @@ gnutls_certificate_allocate_credentials(): %s", LOG(LOG_ERROR, "initialize_tls_session_server(): gnutls_init(): %s", gnutls_strerror(result)); + gnutls_certificate_free_credentials(*x509_cred); return -1; } - gnutls_priority_set(*session, tls_priority_cache); + 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, @@ -400,6 +485,8 @@ gnutls_certificate_allocate_credentials(): %s", 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; } @@ -425,7 +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; @@ -440,16 +527,55 @@ 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 } -#if 0 /* Transfer data between client and server sockets until one closes the * connection. */ static void transfer_data(int client, int server) { @@ -501,6 +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()"); @@ -524,13 +652,14 @@ static int read_from_write_to(int from, int to) { return 0; } -#endif /* 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; @@ -539,6 +668,14 @@ static void transfer_data_tls(int client, int 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) { @@ -548,14 +685,16 @@ static void transfer_data_tls(int client, int server, /* Data available from client. */ if (fds[0].revents & POLLIN || fds[0].revents & POLLPRI) { - if (0 != read_from_write_to_tls(client_session, server_session)) { + 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)) { + if (0 != read_from_write_to_tls(server_session, client_session, + buffer_size)) { /* EOF (or other error) */ break; } @@ -574,26 +713,19 @@ static void transfer_data_tls(int client, int server, /* 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 size; + gnutls_session_t to, + size_t buffer_size) { ssize_t size_read; ssize_t size_written; char buffer[16384]; - /* Get maximum possible buffer size. */ - size = gnutls_record_get_max_size(from); - LOG(LOG_DEBUG, "read_from_write_to_tls(): suggested buffer size: %ld", - (long int)size); - if (size > gnutls_record_get_max_size(to)) { - size = gnutls_record_get_max_size(to); - } - if (size > sizeof(buffer)) { - size = sizeof(buffer); + if (buffer_size > sizeof(buffer)) { + buffer_size = sizeof(buffer); } LOG(LOG_DEBUG, "read_from_write_to_tls(): used buffer size: %ld", - (long int)size); + (long int)buffer_size); - size_read = gnutls_record_recv(from, 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));