/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) 1998 - 2021, Daniel Stenberg, , et al. * * This software is licensed as described in the file COPYING, which * you should have received as part of this distribution. The terms * are also available at https://curl.se/docs/copyright.html. * * You may opt to use, copy, modify, merge, publish, distribute and/or sell * copies of the Software, and permit persons to whom the Software is * furnished to do so, under the terms of the COPYING file. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ***************************************************************************/ #include "server_setup.h" /* Purpose * * 1. Accept a TCP connection on a custom port (IPv4 or IPv6), or connect * to a given (localhost) port. * * 2. Get commands on STDIN. Pass data on to the TCP stream. * Get data from TCP stream and pass on to STDOUT. * * This program is made to perform all the socket/stream/connection stuff for * the test suite's (perl) FTP server. Previously the perl code did all of * this by its own, but I decided to let this program do the socket layer * because of several things: * * o We want the perl code to work with rather old perl installations, thus * we cannot use recent perl modules or features. * * o We want IPv6 support for systems that provide it, and doing optional IPv6 * support in perl seems if not impossible so at least awkward. * * o We want FTP-SSL support, which means that a connection that starts with * plain sockets needs to be able to "go SSL" in the midst. This would also * require some nasty perl stuff I'd rather avoid. * * (Source originally based on sws.c) */ /* * Signal handling notes for sockfilt * ---------------------------------- * * This program is a single-threaded process. * * This program is intended to be highly portable and as such it must be kept * as simple as possible, due to this the only signal handling mechanisms used * will be those of ANSI C, and used only in the most basic form which is good * enough for the purpose of this program. * * For the above reason and the specific needs of this program signals SIGHUP, * SIGPIPE and SIGALRM will be simply ignored on systems where this can be * done. If possible, signals SIGINT and SIGTERM will be handled by this * program as an indication to cleanup and finish execution as soon as * possible. This will be achieved with a single signal handler * 'exit_signal_handler' for both signals. * * The 'exit_signal_handler' upon the first SIGINT or SIGTERM received signal * will just set to one the global var 'got_exit_signal' storing in global var * 'exit_signal' the signal that triggered this change. * * Nothing fancy that could introduce problems is used, the program at certain * points in its normal flow checks if var 'got_exit_signal' is set and in * case this is true it just makes its way out of loops and functions in * structured and well behaved manner to achieve proper program cleanup and * termination. * * Even with the above mechanism implemented it is worthwhile to note that * other signals might still be received, or that there might be systems on * which it is not possible to trap and ignore some of the above signals. * This implies that for increased portability and reliability the program * must be coded as if no signal was being ignored or handled at all. Enjoy * it! */ #ifdef HAVE_SIGNAL_H #include #endif #ifdef HAVE_NETINET_IN_H #include #endif #ifdef HAVE_NETINET_IN6_H #include #endif #ifdef HAVE_ARPA_INET_H #include #endif #ifdef HAVE_NETDB_H #include #endif #define ENABLE_CURLX_PRINTF /* make the curlx header define all printf() functions to use the curlx_* versions instead */ #include "curlx.h" /* from the private lib dir */ #include "getpart.h" #include "inet_pton.h" #include "util.h" #include "server_sockaddr.h" #include "warnless.h" /* include memdebug.h last */ #include "memdebug.h" #ifdef USE_WINSOCK #undef EINTR #define EINTR 4 /* errno.h value */ #undef EAGAIN #define EAGAIN 11 /* errno.h value */ #undef ENOMEM #define ENOMEM 12 /* errno.h value */ #undef EINVAL #define EINVAL 22 /* errno.h value */ #endif #define DEFAULT_PORT 8999 #ifndef DEFAULT_LOGFILE #define DEFAULT_LOGFILE "log/sockfilt.log" #endif const char *serverlogfile = DEFAULT_LOGFILE; static bool verbose = FALSE; static bool bind_only = FALSE; #ifdef ENABLE_IPV6 static bool use_ipv6 = FALSE; #endif static const char *ipv_inuse = "IPv4"; static unsigned short port = DEFAULT_PORT; static unsigned short connectport = 0; /* if non-zero, we activate this mode */ enum sockmode { PASSIVE_LISTEN, /* as a server waiting for connections */ PASSIVE_CONNECT, /* as a server, connected to a client */ ACTIVE, /* as a client, connected to a server */ ACTIVE_DISCONNECT /* as a client, disconnected from server */ }; #ifdef WIN32 /* * read-wrapper to support reading from stdin on Windows. */ static ssize_t read_wincon(int fd, void *buf, size_t count) { HANDLE handle = NULL; DWORD mode, rcount = 0; BOOL success; if(fd == fileno(stdin)) { handle = GetStdHandle(STD_INPUT_HANDLE); } else { return read(fd, buf, count); } if(GetConsoleMode(handle, &mode)) { success = ReadConsole(handle, buf, curlx_uztoul(count), &rcount, NULL); } else { success = ReadFile(handle, buf, curlx_uztoul(count), &rcount, NULL); } if(success) { return rcount; } errno = GetLastError(); return -1; } #undef read #define read(a,b,c) read_wincon(a,b,c) /* * write-wrapper to support writing to stdout and stderr on Windows. */ static ssize_t write_wincon(int fd, const void *buf, size_t count) { HANDLE handle = NULL; DWORD mode, wcount = 0; BOOL success; if(fd == fileno(stdout)) { handle = GetStdHandle(STD_OUTPUT_HANDLE); } else if(fd == fileno(stderr)) { handle = GetStdHandle(STD_ERROR_HANDLE); } else { return write(fd, buf, count); } if(GetConsoleMode(handle, &mode)) { success = WriteConsole(handle, buf, curlx_uztoul(count), &wcount, NULL); } else { success = WriteFile(handle, buf, curlx_uztoul(count), &wcount, NULL); } if(success) { return wcount; } errno = GetLastError(); return -1; } #undef write #define write(a,b,c) write_wincon(a,b,c) #endif /* * fullread is a wrapper around the read() function. This will repeat the call * to read() until it actually has read the complete number of bytes indicated * in nbytes or it fails with a condition that cannot be handled with a simple * retry of the read call. */ static ssize_t fullread(int filedes, void *buffer, size_t nbytes) { int error; ssize_t nread = 0; do { ssize_t rc = read(filedes, (unsigned char *)buffer + nread, nbytes - nread); if(got_exit_signal) { logmsg("signalled to die"); return -1; } if(rc < 0) { error = errno; if((error == EINTR) || (error == EAGAIN)) continue; logmsg("reading from file descriptor: %d,", filedes); logmsg("unrecoverable read() failure: (%d) %s", error, strerror(error)); return -1; } if(rc == 0) { logmsg("got 0 reading from stdin"); return 0; } nread += rc; } while((size_t)nread < nbytes); if(verbose) logmsg("read %zd bytes", nread); return nread; } /* * fullwrite is a wrapper around the write() function. This will repeat the * call to write() until it actually has written the complete number of bytes * indicated in nbytes or it fails with a condition that cannot be handled * with a simple retry of the write call. */ static ssize_t fullwrite(int filedes, const void *buffer, size_t nbytes) { int error; ssize_t nwrite = 0; do { ssize_t wc = write(filedes, (const unsigned char *)buffer + nwrite, nbytes - nwrite); if(got_exit_signal) { logmsg("signalled to die"); return -1; } if(wc < 0) { error = errno; if((error == EINTR) || (error == EAGAIN)) continue; logmsg("writing to file descriptor: %d,", filedes); logmsg("unrecoverable write() failure: (%d) %s", error, strerror(error)); return -1; } if(wc == 0) { logmsg("put 0 writing to stdout"); return 0; } nwrite += wc; } while((size_t)nwrite < nbytes); if(verbose) logmsg("wrote %zd bytes", nwrite); return nwrite; } /* * read_stdin tries to read from stdin nbytes into the given buffer. This is a * blocking function that will only return TRUE when nbytes have actually been * read or FALSE when an unrecoverable error has been detected. Failure of this * function is an indication that the sockfilt process should terminate. */ static bool read_stdin(void *buffer, size_t nbytes) { ssize_t nread = fullread(fileno(stdin), buffer, nbytes); if(nread != (ssize_t)nbytes) { logmsg("exiting..."); return FALSE; } return TRUE; } /* * write_stdout tries to write to stdio nbytes from the given buffer. This is a * blocking function that will only return TRUE when nbytes have actually been * written or FALSE when an unrecoverable error has been detected. Failure of * this function is an indication that the sockfilt process should terminate. */ static bool write_stdout(const void *buffer, size_t nbytes) { ssize_t nwrite = fullwrite(fileno(stdout), buffer, nbytes); if(nwrite != (ssize_t)nbytes) { logmsg("exiting..."); return FALSE; } return TRUE; } static void lograw(unsigned char *buffer, ssize_t len) { char data[120]; ssize_t i; unsigned char *ptr = buffer; char *optr = data; ssize_t width = 0; int left = sizeof(data); for(i = 0; i60) { logmsg("'%s'", data); width = 0; optr = data; left = sizeof(data); } } if(width) logmsg("'%s'", data); } #ifdef USE_WINSOCK /* * WinSock select() does not support standard file descriptors, * it can only check SOCKETs. The following function is an attempt * to re-create a select() function with support for other handle types. * * select() function with support for WINSOCK2 sockets and all * other handle types supported by WaitForMultipleObjectsEx() as * well as disk files, anonymous and names pipes, and character input. * * https://msdn.microsoft.com/en-us/library/windows/desktop/ms687028.aspx * https://msdn.microsoft.com/en-us/library/windows/desktop/ms741572.aspx */ struct select_ws_wait_data { HANDLE handle; /* actual handle to wait for during select */ HANDLE signal; /* internal event to signal handle trigger */ HANDLE abort; /* internal event to abort waiting thread */ HANDLE mutex; /* mutex to prevent event race-condition */ }; static DWORD WINAPI select_ws_wait_thread(LPVOID lpParameter) { struct select_ws_wait_data *data; HANDLE mutex, signal, handle, handles[2]; INPUT_RECORD inputrecord; LARGE_INTEGER size, pos; DWORD type, length, ret; /* retrieve handles from internal structure */ data = (struct select_ws_wait_data *) lpParameter; if(data) { handle = data->handle; handles[0] = data->abort; handles[1] = handle; signal = data->signal; mutex = data->mutex; free(data); } else return (DWORD)-1; /* retrieve the type of file to wait on */ type = GetFileType(handle); switch(type) { case FILE_TYPE_DISK: /* The handle represents a file on disk, this means: * - WaitForMultipleObjectsEx will always be signalled for it. * - comparison of current position in file and total size of * the file can be used to check if we reached the end yet. * * Approach: Loop till either the internal event is signalled * or if the end of the file has already been reached. */ while(WaitForMultipleObjectsEx(1, handles, FALSE, 0, FALSE) == WAIT_TIMEOUT) { ret = WaitForSingleObjectEx(mutex, 0, FALSE); if(ret == WAIT_OBJECT_0) { /* get total size of file */ length = 0; size.QuadPart = 0; size.LowPart = GetFileSize(handle, &length); if((size.LowPart != INVALID_FILE_SIZE) || (GetLastError() == NO_ERROR)) { size.HighPart = length; /* get the current position within the file */ pos.QuadPart = 0; pos.LowPart = SetFilePointer(handle, 0, &pos.HighPart, FILE_CURRENT); if((pos.LowPart != INVALID_SET_FILE_POINTER) || (GetLastError() == NO_ERROR)) { /* compare position with size, abort if not equal */ if(size.QuadPart == pos.QuadPart) { /* sleep and continue waiting */ SleepEx(0, FALSE); ReleaseMutex(mutex); continue; } } } /* there is some data available, stop waiting */ logmsg("[select_ws_wait_thread] data available, DISK: %p", handle); SetEvent(signal); ReleaseMutex(mutex); break; } else if(ret == WAIT_ABANDONED) { /* we are not allowed to process this event, because select_ws is post-processing the signalled events and we must exit. */ break; } } break; case FILE_TYPE_CHAR: /* The handle represents a character input, this means: * - WaitForMultipleObjectsEx will be signalled on any kind of input, * including mouse and window size events we do not care about. * * Approach: Loop till either the internal event is signalled * or we get signalled for an actual key-event. */ while(WaitForMultipleObjectsEx(2, handles, FALSE, INFINITE, FALSE) == WAIT_OBJECT_0 + 1) { ret = WaitForSingleObjectEx(mutex, 0, FALSE); if(ret == WAIT_OBJECT_0) { /* check if this is an actual console handle */ if(GetConsoleMode(handle, &ret)) { /* retrieve an event from the console buffer */ length = 0; if(PeekConsoleInput(handle, &inputrecord, 1, &length)) { /* check if the event is not an actual key-event */ if(length == 1 && inputrecord.EventType != KEY_EVENT) { /* purge the non-key-event and continue waiting */ ReadConsoleInput(handle, &inputrecord, 1, &length); ReleaseMutex(mutex); continue; } } } /* there is some data available, stop waiting */ logmsg("[select_ws_wait_thread] data available, CHAR: %p", handle); SetEvent(signal); ReleaseMutex(mutex); break; } else if(ret == WAIT_ABANDONED) { /* we are not allowed to process this event, because select_ws is post-processing the signalled events and we must exit. */ break; } } break; case FILE_TYPE_PIPE: /* The handle represents an anonymous or named pipe, this means: * - WaitForMultipleObjectsEx will always be signalled for it. * - peek into the pipe and retrieve the amount of data available. * * Approach: Loop till either the internal event is signalled * or there is data in the pipe available for reading. */ while(WaitForMultipleObjectsEx(1, handles, FALSE, 0, FALSE) == WAIT_TIMEOUT) { ret = WaitForSingleObjectEx(mutex, 0, FALSE); if(ret == WAIT_OBJECT_0) { /* peek into the pipe and retrieve the amount of data available */ length = 0; if(PeekNamedPipe(handle, NULL, 0, NULL, &length, NULL)) { /* if there is no data available, sleep and continue waiting */ if(length == 0) { SleepEx(0, FALSE); ReleaseMutex(mutex); continue; } else { logmsg("[select_ws_wait_thread] PeekNamedPipe len: %d", length); } } else { /* if the pipe has NOT been closed, sleep and continue waiting */ ret = GetLastError(); if(ret != ERROR_BROKEN_PIPE) { logmsg("[select_ws_wait_thread] PeekNamedPipe error: %d", ret); SleepEx(0, FALSE); ReleaseMutex(mutex); continue; } else { logmsg("[select_ws_wait_thread] pipe closed, PIPE: %p", handle); } } /* there is some data available, stop waiting */ logmsg("[select_ws_wait_thread] data available, PIPE: %p", handle); SetEvent(signal); ReleaseMutex(mutex); break; } else if(ret == WAIT_ABANDONED) { /* we are not allowed to process this event, because select_ws is post-processing the signalled events and we must exit. */ break; } } break; default: /* The handle has an unknown type, try to wait on it */ if(WaitForMultipleObjectsEx(2, handles, FALSE, INFINITE, FALSE) == WAIT_OBJECT_0 + 1) { if(WaitForSingleObjectEx(mutex, 0, FALSE) == WAIT_OBJECT_0) { logmsg("[select_ws_wait_thread] data available, HANDLE: %p", handle); SetEvent(signal); ReleaseMutex(mutex); } } break; } return 0; } static HANDLE select_ws_wait(HANDLE handle, HANDLE signal, HANDLE abort, HANDLE mutex) { struct select_ws_wait_data *data; HANDLE thread = NULL; /* allocate internal waiting data structure */ data = malloc(sizeof(struct select_ws_wait_data)); if(data) { data->handle = handle; data->signal = signal; data->abort = abort; data->mutex = mutex; /* launch waiting thread */ thread = CreateThread(NULL, 0, &select_ws_wait_thread, data, 0, NULL); /* free data if thread failed to launch */ if(!thread) { free(data); } } return thread; } struct select_ws_data { int fd; /* provided file descriptor (indexed by nfd) */ long wsastate; /* internal pre-select state (indexed by nfd) */ curl_socket_t wsasock; /* internal socket handle (indexed by nws) */ WSAEVENT wsaevent; /* internal select event (indexed by nws) */ HANDLE signal; /* internal thread signal (indexed by nth) */ HANDLE thread; /* internal thread handle (indexed by nth) */ }; static int select_ws(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *tv) { HANDLE abort, mutex, signal, handle, *handles; DWORD timeout_ms, wait, nfd, nth, nws, i; fd_set readsock, writesock, exceptsock; struct select_ws_data *data; WSANETWORKEVENTS wsaevents; curl_socket_t wsasock; int error, ret, fd; WSAEVENT wsaevent; /* check if the input value is valid */ if(nfds < 0) { errno = EINVAL; return -1; } /* convert struct timeval to milliseconds */ if(tv) { timeout_ms = (tv->tv_sec*1000) + (DWORD)(((double)tv->tv_usec)/1000.0); } else { timeout_ms = INFINITE; } /* check if we got descriptors, sleep in case we got none */ if(!nfds) { SleepEx(timeout_ms, FALSE); return 0; } /* create internal event to abort waiting threads */ abort = CreateEvent(NULL, TRUE, FALSE, NULL); if(!abort) { errno = ENOMEM; return -1; } /* create internal mutex to lock event handling in threads */ mutex = CreateMutex(NULL, FALSE, NULL); if(!mutex) { CloseHandle(abort); errno = ENOMEM; return -1; } /* allocate internal array for the internal data */ data = calloc(nfds, sizeof(struct select_ws_data)); if(!data) { CloseHandle(abort); CloseHandle(mutex); errno = ENOMEM; return -1; } /* allocate internal array for the internal event handles */ handles = calloc(nfds + 1, sizeof(HANDLE)); if(!handles) { CloseHandle(abort); CloseHandle(mutex); free(data); errno = ENOMEM; return -1; } /* loop over the handles in the input descriptor sets */ nfd = 0; /* number of handled file descriptors */ nth = 0; /* number of internal waiting threads */ nws = 0; /* number of handled WINSOCK sockets */ for(fd = 0; fd < nfds; fd++) { wsasock = curlx_sitosk(fd); wsaevents.lNetworkEvents = 0; handles[nfd] = 0; FD_ZERO(&readsock); FD_ZERO(&writesock); FD_ZERO(&exceptsock); if(FD_ISSET(wsasock, readfds)) { FD_SET(wsasock, &readsock); wsaevents.lNetworkEvents |= FD_READ|FD_ACCEPT|FD_CLOSE; } if(FD_ISSET(wsasock, writefds)) { FD_SET(wsasock, &writesock); wsaevents.lNetworkEvents |= FD_WRITE|FD_CONNECT|FD_CLOSE; } if(FD_ISSET(wsasock, exceptfds)) { FD_SET(wsasock, &exceptsock); wsaevents.lNetworkEvents |= FD_OOB; } /* only wait for events for which we actually care */ if(wsaevents.lNetworkEvents) { data[nfd].fd = fd; if(fd == fileno(stdin)) { signal = CreateEvent(NULL, TRUE, FALSE, NULL); if(signal) { handle = GetStdHandle(STD_INPUT_HANDLE); handle = select_ws_wait(handle, signal, abort, mutex); if(handle) { handles[nfd] = signal; data[nth].signal = signal; data[nth].thread = handle; nth++; } else { CloseHandle(signal); } } } else if(fd == fileno(stdout)) { handles[nfd] = GetStdHandle(STD_OUTPUT_HANDLE); } else if(fd == fileno(stderr)) { handles[nfd] = GetStdHandle(STD_ERROR_HANDLE); } else { wsaevent = WSACreateEvent(); if(wsaevent != WSA_INVALID_EVENT) { error = WSAEventSelect(wsasock, wsaevent, wsaevents.lNetworkEvents); if(error != SOCKET_ERROR) { handles[nfd] = (HANDLE)wsaevent; data[nws].wsasock = wsasock; data[nws].wsaevent = wsaevent; data[nfd].wsastate = 0; tv->tv_sec = 0; tv->tv_usec = 0; /* check if the socket is already ready */ if(select(fd + 1, &readsock, &writesock, &exceptsock, tv) == 1) { logmsg("[select_ws] socket %d is ready", fd); WSASetEvent(wsaevent); if(FD_ISSET(wsasock, &readsock)) data[nfd].wsastate |= FD_READ; if(FD_ISSET(wsasock, &writesock)) data[nfd].wsastate |= FD_WRITE; if(FD_ISSET(wsasock, &exceptsock)) data[nfd].wsastate |= FD_OOB; } nws++; } else { WSACloseEvent(wsaevent); signal = CreateEvent(NULL, TRUE, FALSE, NULL); if(signal) { handle = (HANDLE)wsasock; handle = select_ws_wait(handle, signal, abort, mutex); if(handle) { handles[nfd] = signal; data[nth].signal = signal; data[nth].thread = handle; nth++; } else { CloseHandle(signal); } } } } } nfd++; } } /* wait on the number of handles */ wait = nfd; /* make sure we stop waiting on exit signal event */ if(exit_event) { /* we allocated handles nfds + 1 for this */ handles[nfd] = exit_event; wait += 1; } /* wait for one of the internal handles to trigger */ wait = WaitForMultipleObjectsEx(wait, handles, FALSE, timeout_ms, FALSE); /* wait for internal mutex to lock event handling in threads */ WaitForSingleObjectEx(mutex, INFINITE, FALSE); /* loop over the internal handles returned in the descriptors */ ret = 0; /* number of ready file descriptors */ for(i = 0; i < nfd; i++) { fd = data[i].fd; handle = handles[i]; wsasock = curlx_sitosk(fd); /* check if the current internal handle was triggered */ if(wait != WAIT_FAILED && (wait - WAIT_OBJECT_0) <= i && WaitForSingleObjectEx(handle, 0, FALSE) == WAIT_OBJECT_0) { /* first handle stdin, stdout and stderr */ if(fd == fileno(stdin)) { /* stdin is never ready for write or exceptional */ FD_CLR(wsasock, writefds); FD_CLR(wsasock, exceptfds); } else if(fd == fileno(stdout) || fd == fileno(stderr)) { /* stdout and stderr are never ready for read or exceptional */ FD_CLR(wsasock, readfds); FD_CLR(wsasock, exceptfds); } else { /* try to handle the event with the WINSOCK2 functions */ wsaevents.lNetworkEvents = 0; error = WSAEnumNetworkEvents(wsasock, handle, &wsaevents); if(error != SOCKET_ERROR) { /* merge result from pre-check using select */ wsaevents.lNetworkEvents |= data[i].wsastate; /* remove from descriptor set if not ready for read/accept/close */ if(!(wsaevents.lNetworkEvents & (FD_READ|FD_ACCEPT|FD_CLOSE))) FD_CLR(wsasock, readfds); /* remove from descriptor set if not ready for write/connect */ if(!(wsaevents.lNetworkEvents & (FD_WRITE|FD_CONNECT|FD_CLOSE))) FD_CLR(wsasock, writefds); /* remove from descriptor set if not exceptional */ if(!(wsaevents.lNetworkEvents & FD_OOB)) FD_CLR(wsasock, exceptfds); } } /* check if the event has not been filtered using specific tests */ if(FD_ISSET(wsasock, readfds) || FD_ISSET(wsasock, writefds) || FD_ISSET(wsasock, exceptfds)) { ret++; } } else { /* remove from all descriptor sets since this handle did not trigger */ FD_CLR(wsasock, readfds); FD_CLR(wsasock, writefds); FD_CLR(wsasock, exceptfds); } } /* signal the event handle for the other waiting threads */ SetEvent(abort); for(fd = 0; fd < nfds; fd++) { if(FD_ISSET(fd, readfds)) logmsg("[select_ws] %d is readable", fd); if(FD_ISSET(fd, writefds)) logmsg("[select_ws] %d is writable", fd); if(FD_ISSET(fd, exceptfds)) logmsg("[select_ws] %d is exceptional", fd); } for(i = 0; i < nws; i++) { WSAEventSelect(data[i].wsasock, NULL, 0); WSACloseEvent(data[i].wsaevent); } for(i = 0; i < nth; i++) { WaitForSingleObjectEx(data[i].thread, INFINITE, FALSE); CloseHandle(data[i].thread); CloseHandle(data[i].signal); } CloseHandle(abort); CloseHandle(mutex); free(handles); free(data); return ret; } #define select(a,b,c,d,e) select_ws(a,b,c,d,e) #endif /* USE_WINSOCK */ /* sockfdp is a pointer to an established stream or CURL_SOCKET_BAD if sockfd is CURL_SOCKET_BAD, listendfd is a listening socket we must accept() */ static bool juggle(curl_socket_t *sockfdp, curl_socket_t listenfd, enum sockmode *mode) { struct timeval timeout; fd_set fds_read; fd_set fds_write; fd_set fds_err; curl_socket_t sockfd = CURL_SOCKET_BAD; int maxfd = -99; ssize_t rc; int error = 0; /* 'buffer' is this excessively large only to be able to support things like test 1003 which tests exceedingly large server response lines */ unsigned char buffer[17010]; char data[16]; if(got_exit_signal) { logmsg("signalled to die, exiting..."); return FALSE; } #ifdef HAVE_GETPPID /* As a last resort, quit if sockfilt process becomes orphan. Just in case parent ftpserver process has died without killing its sockfilt children */ if(getppid() <= 1) { logmsg("process becomes orphan, exiting"); return FALSE; } #endif timeout.tv_sec = 120; timeout.tv_usec = 0; FD_ZERO(&fds_read); FD_ZERO(&fds_write); FD_ZERO(&fds_err); FD_SET((curl_socket_t)fileno(stdin), &fds_read); switch(*mode) { case PASSIVE_LISTEN: /* server mode */ sockfd = listenfd; /* there's always a socket to wait for */ FD_SET(sockfd, &fds_read); maxfd = (int)sockfd; break; case PASSIVE_CONNECT: sockfd = *sockfdp; if(CURL_SOCKET_BAD == sockfd) { /* eeek, we are supposedly connected and then this cannot be -1 ! */ logmsg("socket is -1! on %s:%d", __FILE__, __LINE__); maxfd = 0; /* stdin */ } else { /* there's always a socket to wait for */ FD_SET(sockfd, &fds_read); maxfd = (int)sockfd; } break; case ACTIVE: sockfd = *sockfdp; /* sockfd turns CURL_SOCKET_BAD when our connection has been closed */ if(CURL_SOCKET_BAD != sockfd) { FD_SET(sockfd, &fds_read); maxfd = (int)sockfd; } else { logmsg("No socket to read on"); maxfd = 0; } break; case ACTIVE_DISCONNECT: logmsg("disconnected, no socket to read on"); maxfd = 0; sockfd = CURL_SOCKET_BAD; break; } /* switch(*mode) */ do { /* select() blocking behavior call on blocking descriptors please */ rc = select(maxfd + 1, &fds_read, &fds_write, &fds_err, &timeout); if(got_exit_signal) { logmsg("signalled to die, exiting..."); return FALSE; } } while((rc == -1) && ((error = errno) == EINTR)); if(rc < 0) { logmsg("select() failed with error: (%d) %s", error, strerror(error)); return FALSE; } if(rc == 0) /* timeout */ return TRUE; if(FD_ISSET(fileno(stdin), &fds_read)) { ssize_t buffer_len; /* read from stdin, commands/data to be dealt with and possibly passed on to the socket protocol: 4 letter command + LF [mandatory] 4-digit hexadecimal data length + LF [if the command takes data] data [the data being as long as set above] Commands: DATA - plain pass-through data */ if(!read_stdin(buffer, 5)) return FALSE; logmsg("Received %c%c%c%c (on stdin)", buffer[0], buffer[1], buffer[2], buffer[3]); if(!memcmp("PING", buffer, 4)) { /* send reply on stdout, just proving we are alive */ if(!write_stdout("PONG\n", 5)) return FALSE; } else if(!memcmp("PORT", buffer, 4)) { /* Question asking us what PORT number we are listening to. Replies to PORT with "IPv[num]/[port]" */ msnprintf((char *)buffer, sizeof(buffer), "%s/%hu\n", ipv_inuse, port); buffer_len = (ssize_t)strlen((char *)buffer); msnprintf(data, sizeof(data), "PORT\n%04zx\n", buffer_len); if(!write_stdout(data, 10)) return FALSE; if(!write_stdout(buffer, buffer_len)) return FALSE; } else if(!memcmp("QUIT", buffer, 4)) { /* just die */ logmsg("quits"); return FALSE; } else if(!memcmp("DATA", buffer, 4)) { /* data IN => data OUT */ if(!read_stdin(buffer, 5)) return FALSE; buffer[5] = '\0'; buffer_len = (ssize_t)strtol((char *)buffer, NULL, 16); if(buffer_len > (ssize_t)sizeof(buffer)) { logmsg("ERROR: Buffer size (%zu bytes) too small for data size " "(%zd bytes)", sizeof(buffer), buffer_len); return FALSE; } logmsg("> %zd bytes data, server => client", buffer_len); if(!read_stdin(buffer, buffer_len)) return FALSE; lograw(buffer, buffer_len); if(*mode == PASSIVE_LISTEN) { logmsg("*** We are disconnected!"); if(!write_stdout("DISC\n", 5)) return FALSE; } else { /* send away on the socket */ ssize_t bytes_written = swrite(sockfd, buffer, buffer_len); if(bytes_written != buffer_len) { logmsg("Not all data was sent. Bytes to send: %zd sent: %zd", buffer_len, bytes_written); } } } else if(!memcmp("DISC", buffer, 4)) { /* disconnect! */ if(!write_stdout("DISC\n", 5)) return FALSE; if(sockfd != CURL_SOCKET_BAD) { logmsg("====> Client forcibly disconnected"); sclose(sockfd); *sockfdp = CURL_SOCKET_BAD; if(*mode == PASSIVE_CONNECT) *mode = PASSIVE_LISTEN; else *mode = ACTIVE_DISCONNECT; } else logmsg("attempt to close already dead connection"); return TRUE; } } if((sockfd != CURL_SOCKET_BAD) && (FD_ISSET(sockfd, &fds_read)) ) { ssize_t nread_socket; if(*mode == PASSIVE_LISTEN) { /* there's no stream set up yet, this is an indication that there's a client connecting. */ curl_socket_t newfd = accept(sockfd, NULL, NULL); if(CURL_SOCKET_BAD == newfd) { error = SOCKERRNO; logmsg("accept(%d, NULL, NULL) failed with error: (%d) %s", sockfd, error, strerror(error)); } else { logmsg("====> Client connect"); if(!write_stdout("CNCT\n", 5)) return FALSE; *sockfdp = newfd; /* store the new socket */ *mode = PASSIVE_CONNECT; /* we have connected */ } return TRUE; } /* read from socket, pass on data to stdout */ nread_socket = sread(sockfd, buffer, sizeof(buffer)); if(nread_socket > 0) { msnprintf(data, sizeof(data), "DATA\n%04zx\n", nread_socket); if(!write_stdout(data, 10)) return FALSE; if(!write_stdout(buffer, nread_socket)) return FALSE; logmsg("< %zd bytes data, client => server", nread_socket); lograw(buffer, nread_socket); } if(nread_socket <= 0) { logmsg("====> Client disconnect"); if(!write_stdout("DISC\n", 5)) return FALSE; sclose(sockfd); *sockfdp = CURL_SOCKET_BAD; if(*mode == PASSIVE_CONNECT) *mode = PASSIVE_LISTEN; else *mode = ACTIVE_DISCONNECT; return TRUE; } } return TRUE; } static curl_socket_t sockdaemon(curl_socket_t sock, unsigned short *listenport) { /* passive daemon style */ srvr_sockaddr_union_t listener; int flag; int rc; int totdelay = 0; int maxretr = 10; int delay = 20; int attempt = 0; int error = 0; do { attempt++; flag = 1; rc = setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&flag, sizeof(flag)); if(rc) { error = SOCKERRNO; logmsg("setsockopt(SO_REUSEADDR) failed with error: (%d) %s", error, strerror(error)); if(maxretr) { rc = wait_ms(delay); if(rc) { /* should not happen */ error = errno; logmsg("wait_ms() failed with error: (%d) %s", error, strerror(error)); sclose(sock); return CURL_SOCKET_BAD; } if(got_exit_signal) { logmsg("signalled to die, exiting..."); sclose(sock); return CURL_SOCKET_BAD; } totdelay += delay; delay *= 2; /* double the sleep for next attempt */ } } } while(rc && maxretr--); if(rc) { logmsg("setsockopt(SO_REUSEADDR) failed %d times in %d ms. Error: (%d) %s", attempt, totdelay, error, strerror(error)); logmsg("Continuing anyway..."); } /* When the specified listener port is zero, it is actually a request to let the system choose a non-zero available port. */ #ifdef ENABLE_IPV6 if(!use_ipv6) { #endif memset(&listener.sa4, 0, sizeof(listener.sa4)); listener.sa4.sin_family = AF_INET; listener.sa4.sin_addr.s_addr = INADDR_ANY; listener.sa4.sin_port = htons(*listenport); rc = bind(sock, &listener.sa, sizeof(listener.sa4)); #ifdef ENABLE_IPV6 } else { memset(&listener.sa6, 0, sizeof(listener.sa6)); listener.sa6.sin6_family = AF_INET6; listener.sa6.sin6_addr = in6addr_any; listener.sa6.sin6_port = htons(*listenport); rc = bind(sock, &listener.sa, sizeof(listener.sa6)); } #endif /* ENABLE_IPV6 */ if(rc) { error = SOCKERRNO; logmsg("Error binding socket on port %hu: (%d) %s", *listenport, error, strerror(error)); sclose(sock); return CURL_SOCKET_BAD; } if(!*listenport) { /* The system was supposed to choose a port number, figure out which port we actually got and update the listener port value with it. */ curl_socklen_t la_size; srvr_sockaddr_union_t localaddr; #ifdef ENABLE_IPV6 if(!use_ipv6) #endif la_size = sizeof(localaddr.sa4); #ifdef ENABLE_IPV6 else la_size = sizeof(localaddr.sa6); #endif memset(&localaddr.sa, 0, (size_t)la_size); if(getsockname(sock, &localaddr.sa, &la_size) < 0) { error = SOCKERRNO; logmsg("getsockname() failed with error: (%d) %s", error, strerror(error)); sclose(sock); return CURL_SOCKET_BAD; } switch(localaddr.sa.sa_family) { case AF_INET: *listenport = ntohs(localaddr.sa4.sin_port); break; #ifdef ENABLE_IPV6 case AF_INET6: *listenport = ntohs(localaddr.sa6.sin6_port); break; #endif default: break; } if(!*listenport) { /* Real failure, listener port shall not be zero beyond this point. */ logmsg("Apparently getsockname() succeeded, with listener port zero."); logmsg("A valid reason for this failure is a binary built without"); logmsg("proper network library linkage. This might not be the only"); logmsg("reason, but double check it before anything else."); sclose(sock); return CURL_SOCKET_BAD; } } /* bindonly option forces no listening */ if(bind_only) { logmsg("instructed to bind port without listening"); return sock; } /* start accepting connections */ rc = listen(sock, 5); if(0 != rc) { error = SOCKERRNO; logmsg("listen(%d, 5) failed with error: (%d) %s", sock, error, strerror(error)); sclose(sock); return CURL_SOCKET_BAD; } return sock; } int main(int argc, char *argv[]) { srvr_sockaddr_union_t me; curl_socket_t sock = CURL_SOCKET_BAD; curl_socket_t msgsock = CURL_SOCKET_BAD; int wrotepidfile = 0; const char *pidname = ".sockfilt.pid"; const char *portfile = NULL; /* none by default */ bool juggle_again; int rc; int error; int arg = 1; enum sockmode mode = PASSIVE_LISTEN; /* default */ const char *addr = NULL; while(argc>arg) { if(!strcmp("--version", argv[arg])) { printf("sockfilt IPv4%s\n", #ifdef ENABLE_IPV6 "/IPv6" #else "" #endif ); return 0; } else if(!strcmp("--verbose", argv[arg])) { verbose = TRUE; arg++; } else if(!strcmp("--pidfile", argv[arg])) { arg++; if(argc>arg) pidname = argv[arg++]; } else if(!strcmp("--portfile", argv[arg])) { arg++; if(argc > arg) portfile = argv[arg++]; } else if(!strcmp("--logfile", argv[arg])) { arg++; if(argc>arg) serverlogfile = argv[arg++]; } else if(!strcmp("--ipv6", argv[arg])) { #ifdef ENABLE_IPV6 ipv_inuse = "IPv6"; use_ipv6 = TRUE; #endif arg++; } else if(!strcmp("--ipv4", argv[arg])) { /* for completeness, we support this option as well */ #ifdef ENABLE_IPV6 ipv_inuse = "IPv4"; use_ipv6 = FALSE; #endif arg++; } else if(!strcmp("--bindonly", argv[arg])) { bind_only = TRUE; arg++; } else if(!strcmp("--port", argv[arg])) { arg++; if(argc>arg) { char *endptr; unsigned long ulnum = strtoul(argv[arg], &endptr, 10); port = curlx_ultous(ulnum); arg++; } } else if(!strcmp("--connect", argv[arg])) { /* Asked to actively connect to the specified local port instead of doing a passive server-style listening. */ arg++; if(argc>arg) { char *endptr; unsigned long ulnum = strtoul(argv[arg], &endptr, 10); if((endptr != argv[arg] + strlen(argv[arg])) || (ulnum < 1025UL) || (ulnum > 65535UL)) { fprintf(stderr, "sockfilt: invalid --connect argument (%s)\n", argv[arg]); return 0; } connectport = curlx_ultous(ulnum); arg++; } } else if(!strcmp("--addr", argv[arg])) { /* Set an IP address to use with --connect; otherwise use localhost */ arg++; if(argc>arg) { addr = argv[arg]; arg++; } } else { puts("Usage: sockfilt [option]\n" " --version\n" " --verbose\n" " --logfile [file]\n" " --pidfile [file]\n" " --ipv4\n" " --ipv6\n" " --bindonly\n" " --port [port]\n" " --connect [port]\n" " --addr [address]"); return 0; } } #ifdef WIN32 win32_init(); atexit(win32_cleanup); setmode(fileno(stdin), O_BINARY); setmode(fileno(stdout), O_BINARY); setmode(fileno(stderr), O_BINARY); #endif install_signal_handlers(false); #ifdef ENABLE_IPV6 if(!use_ipv6) #endif sock = socket(AF_INET, SOCK_STREAM, 0); #ifdef ENABLE_IPV6 else sock = socket(AF_INET6, SOCK_STREAM, 0); #endif if(CURL_SOCKET_BAD == sock) { error = SOCKERRNO; logmsg("Error creating socket: (%d) %s", error, strerror(error)); write_stdout("FAIL\n", 5); goto sockfilt_cleanup; } if(connectport) { /* Active mode, we should connect to the given port number */ mode = ACTIVE; #ifdef ENABLE_IPV6 if(!use_ipv6) { #endif memset(&me.sa4, 0, sizeof(me.sa4)); me.sa4.sin_family = AF_INET; me.sa4.sin_port = htons(connectport); me.sa4.sin_addr.s_addr = INADDR_ANY; if(!addr) addr = "127.0.0.1"; Curl_inet_pton(AF_INET, addr, &me.sa4.sin_addr); rc = connect(sock, &me.sa, sizeof(me.sa4)); #ifdef ENABLE_IPV6 } else { memset(&me.sa6, 0, sizeof(me.sa6)); me.sa6.sin6_family = AF_INET6; me.sa6.sin6_port = htons(connectport); if(!addr) addr = "::1"; Curl_inet_pton(AF_INET6, addr, &me.sa6.sin6_addr); rc = connect(sock, &me.sa, sizeof(me.sa6)); } #endif /* ENABLE_IPV6 */ if(rc) { error = SOCKERRNO; logmsg("Error connecting to port %hu: (%d) %s", connectport, error, strerror(error)); write_stdout("FAIL\n", 5); goto sockfilt_cleanup; } logmsg("====> Client connect"); msgsock = sock; /* use this as stream */ } else { /* passive daemon style */ sock = sockdaemon(sock, &port); if(CURL_SOCKET_BAD == sock) { write_stdout("FAIL\n", 5); goto sockfilt_cleanup; } msgsock = CURL_SOCKET_BAD; /* no stream socket yet */ } logmsg("Running %s version", ipv_inuse); if(connectport) logmsg("Connected to port %hu", connectport); else if(bind_only) logmsg("Bound without listening on port %hu", port); else logmsg("Listening on port %hu", port); wrotepidfile = write_pidfile(pidname); if(!wrotepidfile) { write_stdout("FAIL\n", 5); goto sockfilt_cleanup; } if(portfile) { wrotepidfile = write_portfile(portfile, port); if(!wrotepidfile) { write_stdout("FAIL\n", 5); goto sockfilt_cleanup; } } do { juggle_again = juggle(&msgsock, sock, &mode); } while(juggle_again); sockfilt_cleanup: if((msgsock != sock) && (msgsock != CURL_SOCKET_BAD)) sclose(msgsock); if(sock != CURL_SOCKET_BAD) sclose(sock); if(wrotepidfile) unlink(pidname); restore_signal_handlers(false); if(got_exit_signal) { logmsg("============> sockfilt exits with signal (%d)", exit_signal); /* * To properly set the return status of the process we * must raise the same signal SIGINT or SIGTERM that we * caught and let the old handler take care of it. */ raise(exit_signal); } logmsg("============> sockfilt quits"); return 0; }