/*
* 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
#include <errno.h>
-/* 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
+/* 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\
+<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">\n\
+<html>\n\
+<head><title>%s</title></head>\n\
+<body>\n\
+<h1>%s</h1>\n\
+<p>%s</p>\n\
+</body>\n\
+</html>\n"
+
static int initialize_tls_session_client(int peer_socket,
const char *hostname,
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_server_error(gnutls_session_t session);
+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);
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
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_session_init = 0;
client_session_started = 0;
server_session_started = 0;
+ validation_failed = 0;
client_fd = fdopen(client_socket, "a+");
if (NULL == client_fd) {
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;
- /* Initialize TLS server credentials to talk to the client. */
- result = initialize_tls_session_client(client_socket, 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;
+ 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, "starting client TLS handshake");
+ LOG(LOG_DEBUG, "transferring data");
- /* 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;
+ /* Proxy data between client and server until one side is done
+ * (EOF or error). */
+ transfer_data(client_socket, server_socket);
- LOG(LOG_DEBUG, "client TLS handshake finished");
+ 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);
- /* 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);
}
server_session_started = 1;
- LOG(LOG_DEBUG, "server TLS handshake finished, transferring data");
+ 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!");
- tls_send_server_error(client_session);
+ /* 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;
- /* Proxy data between client and server until one suite is done (EOF or
+ /* 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. */
+ 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 data");
+ LOG(LOG_DEBUG, "finished transferring TLS data");
out:
/* Close TLS sessions if necessary. Use GNUTLS_SHUT_RDWR so the data is
gnutls_session_t *session,
gnutls_certificate_credentials_t *x509_cred) {
int result;
+ int use_invalid_cert;
char path[1024];
- /* Hostname too long. */
- if (sizeof(path) - strlen(PROXY_SERVER_CERT_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), PROXY_SERVER_CERT_FORMAT, hostname);
result = gnutls_certificate_allocate_credentials(x509_cred);
if (GNUTLS_E_SUCCESS != result) {
}
/* 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,
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;
}
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,
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;
}
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;
}
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_server_error(gnutls_session_t session) {
- gnutls_record_send(session, "HTTP/1.0 500 Internal Server Error\r\n", 36);
- gnutls_record_send(session, "\r\n", 2);
+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) {
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()");
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;
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) {
/* 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;
}
/* 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));
ruderich.org/simon / tlsproxy / tlsproxy.git / blobdiff