From 8c4e41d4ed8b3d8c3a39d3bef01feec98dc82161 Mon Sep 17 00:00:00 2001 From: Simon Ruderich Date: Sun, 28 Jul 2013 13:52:11 +0200 Subject: [PATCH] Don't use fdopen(socket, "a+"). Using it with sockets is undefined behaviour as correct usage of a+ requires seeking which is not possible on sockets. Instead use separate read and write FILE *. --- src/connection.c | 95 ++++++++++++++++++++++++++++++------------------ 1 file changed, 60 insertions(+), 35 deletions(-) diff --git a/src/connection.c b/src/connection.c index 82b13bf..f7e9a97 100644 --- a/src/connection.c +++ b/src/connection.c @@ -58,6 +58,7 @@ static int initialize_tls_session_server(int peer_socket, gnutls_session_t *session, gnutls_certificate_credentials_t *x509_cred); +static int fdopen_read_write(int socket, FILE **read_fd, FILE **write_fd); 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); @@ -79,7 +80,7 @@ static int parse_request(const char *buffer, char *host, char *port, void handle_connection(int client_socket) { int server_socket; - FILE *client_fd, *server_fd; + FILE *client_fd_read, *client_fd_write, *server_fd_read, *server_fd_write; char buffer[MAX_REQUEST_LINE]; char host[MAX_REQUEST_LINE]; @@ -105,34 +106,35 @@ void handle_connection(int client_socket) { LOG(LOG_DEBUG, "new connection"); server_socket = -1; - client_fd = NULL; - server_fd = NULL; + client_fd_read = NULL; + client_fd_write = NULL; + server_fd_read = NULL; + server_fd_write = 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 (client_fd == NULL) { - LOG_PERROR(LOG_WARNING, "fdopen(): client failed"); + if (fdopen_read_write(client_socket, &client_fd_read, + &client_fd_write) != 0) { goto out; } /* Read request line (CONNECT ..) and headers (they are discarded). */ - result = read_http_request(client_fd, buffer, sizeof(buffer)); + result = read_http_request(client_fd_read, buffer, sizeof(buffer)); if (result == -1) { LOG(LOG_WARNING, "read_http_request(): client read error"); goto out; } else if (result == -2) { LOG(LOG_WARNING, "read_http_request(): client EOF"); - send_bad_request(client_fd); + send_bad_request(client_fd_write); goto out; } if (parse_request(buffer, host, port, &version_minor) != 0) { LOG(LOG_WARNING, "bad request: %s", buffer); - send_bad_request(client_fd); + send_bad_request(client_fd_write); goto out; } @@ -150,38 +152,37 @@ void handle_connection(int client_socket) { if (server_socket == -1) { LOG(LOG_WARNING, "failed to connect to server"); - send_forwarding_failure(client_fd); + send_forwarding_failure(client_fd_write); goto out; } - server_fd = fdopen(server_socket, "a+"); - if (server_fd == NULL) { - LOG_PERROR(LOG_WARNING, "fdopen(): server failed"); - send_forwarding_failure(client_fd); + if (fdopen_read_write(server_socket, &server_fd_read, + &server_fd_write) != 0) { + send_forwarding_failure(client_fd_write); goto out; } /* Connect to proxy if requested (command line option). */ if (global_proxy_host != NULL && global_proxy_port != NULL) { - fprintf(server_fd, "CONNECT %s:%s HTTP/1.0\r\n", host, port); - fprintf(server_fd, "\r\n"); - fflush(server_fd); + fprintf(server_fd_write, "CONNECT %s:%s HTTP/1.0\r\n", host, port); + fprintf(server_fd_write, "\r\n"); + fflush(server_fd_write); /* Read response line from proxy server. */ - result = read_http_request(server_fd, buffer, sizeof(buffer)); + result = read_http_request(server_fd_read, buffer, sizeof(buffer)); if (result == -1) { LOG(LOG_WARNING, "read_http_request(): proxy read error"); - send_forwarding_failure(client_fd); + send_forwarding_failure(client_fd_write); goto out; } else if (result == -2) { LOG(LOG_WARNING, "read_http_request(): proxy EOF"); - send_forwarding_failure(client_fd); + send_forwarding_failure(client_fd_write); goto out; } /* Check response of proxy server. */ if (strncmp(buffer, "HTTP/1.0 200", 12)) { LOG(LOG_WARNING, "bad proxy response: %s", buffer); - send_forwarding_failure(client_fd); + send_forwarding_failure(client_fd_write); goto out; } } @@ -197,9 +198,9 @@ void handle_connection(int client_socket) { if (server_certificate_file(&file, host, path, sizeof(path)) == -2) { /* 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); + fprintf(client_fd_write, "HTTP/1.0 200 Connection established\r\n"); + fprintf(client_fd_write, "\r\n"); + fflush(client_fd_write); LOG(LOG_DEBUG, "transferring data"); @@ -222,7 +223,7 @@ void handle_connection(int client_socket) { &server_x509_cred); if (result != 0) { LOG(LOG_WARNING, "initialize_tls_session_server() failed"); - send_forwarding_failure(client_fd); + send_forwarding_failure(client_fd_write); goto out; } server_session_init = 1; @@ -234,7 +235,7 @@ void handle_connection(int client_socket) { if (result != GNUTLS_E_SUCCESS) { LOG(LOG_WARNING, "server TLS handshake failed: %s", gnutls_strerror(result)); - send_forwarding_failure(client_fd); + send_forwarding_failure(client_fd_write); goto out; } server_session_started = 1; @@ -260,15 +261,15 @@ void handle_connection(int client_socket) { &client_x509_cred); if (result != 0) { LOG(LOG_WARNING, "initialize_tls_session_client() failed"); - send_forwarding_failure(client_fd); + send_forwarding_failure(client_fd_write); 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); + fprintf(client_fd_write, "HTTP/1.0 200 Connection established\r\n"); + fprintf(client_fd_write, "\r\n"); + fflush(client_fd_write); LOG(LOG_DEBUG, "starting client TLS handshake"); @@ -277,7 +278,7 @@ void handle_connection(int client_socket) { if (result != GNUTLS_E_SUCCESS) { LOG(LOG_WARNING, "client TLS handshake failed: %s", gnutls_strerror(result)); - send_forwarding_failure(client_fd); + send_forwarding_failure(client_fd_write); goto out; } client_session_started = 1; @@ -322,15 +323,21 @@ out: } /* Close connection to server/proxy. */ - if (server_fd != NULL) { - fclose(server_fd); + if (server_fd_read != NULL) { + if (server_fd_write != NULL) { + fclose(server_fd_write); + } + fclose(server_fd_read); } else if (server_socket != -1) { close(server_socket); } LOG(LOG_DEBUG, "connection to server closed"); /* Close connection to client. */ - if (client_fd != NULL) { - fclose(client_fd); + if (client_fd_read != NULL) { + if (client_fd_write != NULL) { + fclose(client_fd_write); + } + fclose(client_fd_read); } else { close(client_socket); } @@ -489,6 +496,24 @@ gnutls_certificate_allocate_credentials(): %s", } +static int fdopen_read_write(int socket, FILE **read_fd, FILE **write_fd) { + *read_fd = fdopen(socket, "r"); + if (*read_fd == NULL) { + LOG_PERROR(LOG_WARNING, "fdopen_read_write(): fdopen(\"r\") failed"); + return -1; + } + + *write_fd = fdopen(dup(socket), "w"); + if (*write_fd == NULL) { + LOG_PERROR(LOG_WARNING, "fdopen_read_write(): fdopen(\"w\") failed"); + fclose(*read_fd); + *read_fd = NULL; /* "tell" caller read_fd is already closed */ + return -1; + } + + return 0; +} + /* Read HTTP request line and headers (ignored). * * On success 0 is returned, -1 on client error, -2 on unexpected EOF. -- 2.45.2