X-Git-Url: https://ruderich.org/simon/gitweb/?a=blobdiff_plain;f=src%2Fconnection.c;h=2732f30caa9b700e3d6664262312c14a46afd8d5;hb=8bc073500cb894b9fd974b53801f7daa86e96d12;hp=7ea6eb24a7573dd14d5d21facf89a06dc2546c9d;hpb=8db64b0eebeaa80e46b2df40b91af741e533e7bc;p=tlsproxy%2Ftlsproxy.git diff --git a/src/connection.c b/src/connection.c index 7ea6eb2..2732f30 100644 --- a/src/connection.c +++ b/src/connection.c @@ -19,6 +19,7 @@ #include "tlsproxy.h" #include "connection.h" +#include "verify.h" /* close() */ #include @@ -35,10 +36,6 @@ * should be a good limit to make processing simpler. */ #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" - static int initialize_tls_session_client(int peer_socket, const char *hostname, @@ -51,6 +48,7 @@ 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); @@ -88,6 +86,9 @@ 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 +99,7 @@ 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 +179,44 @@ 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); + 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); + 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. */ + 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 special host if the server + * certificate was invalid */ + (validation_failed) ? "invalid" + : host, &client_session, &client_x509_cred); if (0 != result) { @@ -193,6 +226,11 @@ 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. */ @@ -207,31 +245,15 @@ 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 data"); /* Proxy data between client and server until one suite is done (EOF or * error). */ @@ -241,12 +263,13 @@ void handle_connection(int client_socket) { LOG(LOG_DEBUG, "finished transferring 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); @@ -283,13 +306,15 @@ 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" + + /* 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"); /* Hostname too long. */ - if (sizeof(path) - strlen(PATH_FORMAT) <= strlen(hostname)) { + if (sizeof(path) - strlen(PROXY_SERVER_CERT_FORMAT) <= strlen(hostname)) { LOG(LOG_WARNING, "initialize_tls_session_client(): hostname too long: '%s'", hostname); @@ -302,8 +327,7 @@ static int initialize_tls_session_client(int peer_socket, hostname); return -1; } - snprintf(path, sizeof(path), PATH_FORMAT, hostname); -#undef PATH_FORMAT + snprintf(path, sizeof(path), PROXY_SERVER_CERT_FORMAT, hostname); result = gnutls_certificate_allocate_credentials(x509_cred); if (GNUTLS_E_SUCCESS != result) { @@ -315,9 +339,15 @@ 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 (!use_invalid_cert) { + result = gnutls_certificate_set_x509_trust_file(*x509_cred, + PROXY_CA_FILE, + GNUTLS_X509_FMT_PEM); + /* If the invalid hostname was specified do nothing, we use a self-signed + * certificate in this case. */ + } else { + result = 1; + } if (0 >= result) { LOG(LOG_ERROR, "initialize_tls_session_client(): can't read CA file: '%s'", @@ -325,9 +355,18 @@ gnutls_certificate_allocate_credentials(): %s", return -1; } /* 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(): \ @@ -447,6 +486,10 @@ static void send_forwarding_failure(FILE *client_fd) { fprintf(client_fd, "HTTP/1.0 503 Forwarding failure\r\n"); fprintf(client_fd, "\r\n"); } +static void tls_send_invalid_cert_message(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); +} #if 0