/* * Copyright (C) 1997-2000 Matt Newman * Copyright (C) 2000 Ajuba Solutions * * TLS (aka SSL) Channel - can be layered on any bi-directional * Tcl_Channel (Note: Requires Trf Core Patch) * * This was built from scratch based upon observation of OpenSSL 0.9.2B * * Addition credit is due for Andreas Kupries (a.kupries@westend.com), for * providing the Tcl_ReplaceChannel mechanism and working closely with me * to enhance it to support full fileevent semantics. * * Also work done by the follow people provided the impetus to do this "right": * tclSSL (Colin McCormack, Shared Technology) * SSLtcl (Peter Antman) * */ #include "tlsInt.h" /* * Forward declarations */ static int TlsBlockModeProc _ANSI_ARGS_((ClientData instanceData, int mode)); static int TlsCloseProc _ANSI_ARGS_((ClientData instanceData, Tcl_Interp *interp)); static int TlsInputProc _ANSI_ARGS_((ClientData instanceData, char *buf, int bufSize, int *errorCodePtr)); static int TlsOutputProc _ANSI_ARGS_((ClientData instanceData, CONST char *buf, int toWrite, int *errorCodePtr)); static int TlsGetOptionProc _ANSI_ARGS_((ClientData instanceData, Tcl_Interp *interp, CONST84 char *optionName, Tcl_DString *dsPtr)); static void TlsWatchProc _ANSI_ARGS_((ClientData instanceData, int mask)); static int TlsGetHandleProc _ANSI_ARGS_((ClientData instanceData, int direction, ClientData *handlePtr)); static int TlsNotifyProc _ANSI_ARGS_((ClientData instanceData, int mask)); #if 0 static void TlsChannelHandler _ANSI_ARGS_((ClientData clientData, int mask)); #endif static void TlsChannelHandlerTimer _ANSI_ARGS_((ClientData clientData)); /* * TLS Channel Type */ static Tcl_ChannelType *tlsChannelType = NULL; /* *------------------------------------------------------------------- * * Tls_ChannelType -- * * Return the correct TLS channel driver info * * Results: * The correct channel driver for the current version of Tcl. * * Side effects: * None. * *------------------------------------------------------------------- */ Tcl_ChannelType *Tls_ChannelType(void) { unsigned int size; /* * Initialize the channel type if necessary */ if (tlsChannelType == NULL) { /* * Allocation of a new channeltype structure is not easy, because of * the various verson of the core and subsequent changes to the * structure. The main challenge is to allocate enough memory for * modern versions even if this extsension is compiled against one * of the older variant! * * (1) Versions before stubs (8.0.x) are simple, because they are * supported only if the extension is compiled against exactly * that version of the core. * * (2) With stubs we just determine the difference between the older * and modern variant and overallocate accordingly if compiled * against an older variant. */ size = sizeof(Tcl_ChannelType); /* Base size */ tlsChannelType = (Tcl_ChannelType *) ckalloc(size); memset((VOID *) tlsChannelType, 0, size); /* * Common elements of the structure (no changes in location or name) * close2Proc, seekProc, setOptionProc stay NULL. */ tlsChannelType->typeName = "tls"; tlsChannelType->closeProc = TlsCloseProc; tlsChannelType->inputProc = TlsInputProc; tlsChannelType->outputProc = TlsOutputProc; tlsChannelType->getOptionProc = TlsGetOptionProc; tlsChannelType->watchProc = TlsWatchProc; tlsChannelType->getHandleProc = TlsGetHandleProc; /* * Compiled against 8.3.2+. Direct access to all elements possible. Use * channelTypeVersion information to select the values to use. */ /* * For the 8.3.2 core we present ourselves as a version 2 * driver. This means a special value in version (ex * blockModeProc), blockModeProc in a different place and of * course usage of the handlerProc. */ tlsChannelType->version = TCL_CHANNEL_VERSION_2; tlsChannelType->blockModeProc = TlsBlockModeProc; tlsChannelType->handlerProc = TlsNotifyProc; } return(tlsChannelType); } /* *------------------------------------------------------------------- * * TlsBlockModeProc -- * * This procedure is invoked by the generic IO level * to set blocking and nonblocking modes * Results: * 0 if successful, errno when failed. * * Side effects: * Sets the device into blocking or nonblocking mode. * *------------------------------------------------------------------- */ static int TlsBlockModeProc(ClientData instanceData, int mode) { State *statePtr = (State *) instanceData; if (mode == TCL_MODE_NONBLOCKING) { statePtr->flags |= TLS_TCL_ASYNC; } else { statePtr->flags &= ~(TLS_TCL_ASYNC); } return(0); } /* *------------------------------------------------------------------- * * TlsCloseProc -- * * This procedure is invoked by the generic IO level to perform * channel-type-specific cleanup when a SSL socket based channel * is closed. * * Note: we leave the underlying socket alone, is this right? * * Results: * 0 if successful, the value of Tcl_GetErrno() if failed. * * Side effects: * Closes the socket of the channel. * *------------------------------------------------------------------- */ static int TlsCloseProc(ClientData instanceData, /* The socket to close. */ Tcl_Interp *interp) /* For error reporting - unused. */ { State *statePtr = (State *) instanceData; dprintf("TlsCloseProc(%p)", (void *) statePtr); Tls_Clean(statePtr); Tcl_EventuallyFree((ClientData)statePtr, Tls_Free); dprintf("Returning TCL_OK"); return TCL_OK; } /* *------------------------------------------------------------------- * * TlsInputProc -- * * This procedure is invoked by the generic IO level * to read input from a SSL socket based channel. * * Results: * The number of bytes read is returned or -1 on error. An output * argument contains the POSIX error code on error, or zero if no * error occurred. * * Side effects: * Reads input from the input device of the channel. * *------------------------------------------------------------------- */ static int TlsInputProc(ClientData instanceData, char *buf, int bufSize, int *errorCodePtr) { State *statePtr = (State *) instanceData; int bytesRead; int tlsConnect; int err; *errorCodePtr = 0; dprintf("BIO_read(%d)", bufSize); if (statePtr->flags & TLS_TCL_CALLBACK) { /* don't process any bytes while verify callback is running */ dprintf("Callback is running, reading 0 bytes"); bytesRead = 0; return(0); } dprintf("Calling Tls_WaitForConnect"); tlsConnect = Tls_WaitForConnect(statePtr, errorCodePtr); if (tlsConnect < 0) { dprintf("Got an error (bytesRead = %i)", bytesRead); if (*errorCodePtr == ECONNRESET) { dprintf("Got connection reset"); /* Soft EOF */ *errorCodePtr = 0; bytesRead = 0; } return(bytesRead); } if (statePtr->flags & TLS_TCL_INIT) { statePtr->flags &= ~(TLS_TCL_INIT); } /* * We need to clear the SSL error stack now because we sometimes reach * this function with leftover errors in the stack. If BIO_read * returns -1 and intends EAGAIN, there is a leftover error, it will be * misconstrued as an error, not EAGAIN. * * Alternatively, we may want to handle the <0 return codes from * BIO_read specially (as advised in the RSA docs). TLS's lower level BIO * functions play with the retry flags though, and this seems to work * correctly. Similar fix in TlsOutputProc. - hobbs */ ERR_clear_error(); bytesRead = BIO_read(statePtr->bio, buf, bufSize); dprintf("BIO_read -> %d", bytesRead); err = SSL_get_error(statePtr->ssl, bytesRead); if (BIO_should_retry(statePtr->bio)) { dprintf("I/O failed, will retry based on EAGAIN"); *errorCodePtr = EAGAIN; } switch (err) { case SSL_ERROR_NONE: dprintBuffer(buf, bytesRead); break; case SSL_ERROR_SSL: Tls_Error(statePtr, TCLTLS_SSL_ERROR(statePtr->ssl, bytesRead)); *errorCodePtr = ECONNABORTED; break; case SSL_ERROR_SYSCALL: dprintf("I/O error reading, treating it as EOF"); *errorCodePtr = 0; bytesRead = 0; break; } input: dprintf("Input(%d) -> %d [%d]", bufSize, bytesRead, *errorCodePtr); return bytesRead; } /* *------------------------------------------------------------------- * * TlsOutputProc -- * * This procedure is invoked by the generic IO level * to write output to a SSL socket based channel. * * Results: * The number of bytes written is returned. An output argument is * set to a POSIX error code if an error occurred, or zero. * * Side effects: * Writes output on the output device of the channel. * *------------------------------------------------------------------- */ static int TlsOutputProc(ClientData instanceData, CONST char *buf, int toWrite, int *errorCodePtr) { State *statePtr = (State *) instanceData; int written, err; *errorCodePtr = 0; dprintf("BIO_write(%p, %d)", (void *) statePtr, toWrite); dprintBuffer(buf, toWrite); if (statePtr->flags & TLS_TCL_CALLBACK) { dprintf("Don't process output while callbacks are running") written = -1; *errorCodePtr = EAGAIN; return(-1); } dprintf("Calling Tls_WaitForConnect"); written = Tls_WaitForConnect(statePtr, errorCodePtr); if (written < 0) { dprintf("Tls_WaitForConnect returned %i (err = %i)", written, *errorCodePtr); return(-1); } if (toWrite == 0) { dprintf("zero-write"); BIO_flush(statePtr->bio); written = 0; *errorCodePtr = 0; return(0); } /* * We need to clear the SSL error stack now because we sometimes reach * this function with leftover errors in the stack. If BIO_write * returns -1 and intends EAGAIN, there is a leftover error, it will be * misconstrued as an error, not EAGAIN. * * Alternatively, we may want to handle the <0 return codes from * BIO_write specially (as advised in the RSA docs). TLS's lower level * BIO functions play with the retry flags though, and this seems to * work correctly. Similar fix in TlsInputProc. - hobbs */ ERR_clear_error(); written = BIO_write(statePtr->bio, buf, toWrite); dprintf("BIO_write(%p, %d) -> [%d]", (void *) statePtr, toWrite, written); err = SSL_get_error(statePtr->ssl, written); switch (err) { case SSL_ERROR_NONE: if (written < 0) { written = 0; } break; case SSL_ERROR_WANT_WRITE: dprintf(" write W BLOCK"); break; case SSL_ERROR_WANT_READ: dprintf(" write R BLOCK"); break; case SSL_ERROR_WANT_X509_LOOKUP: dprintf(" write X BLOCK"); break; case SSL_ERROR_ZERO_RETURN: dprintf(" closed"); written = 0; break; case SSL_ERROR_SYSCALL: *errorCodePtr = Tcl_GetErrno(); dprintf(" [%d] syscall errr: %d", written, *errorCodePtr); written = -1; break; case SSL_ERROR_SSL: Tls_Error(statePtr, TCLTLS_SSL_ERROR(statePtr->ssl, written)); *errorCodePtr = ECONNABORTED; written = -1; break; default: dprintf(" unknown err: %d", err); break; } output: dprintf("Output(%d) -> %d", toWrite, written); return(written); } /* *------------------------------------------------------------------- * * TlsGetOptionProc -- * * Computes an option value for a SSL socket based channel, or a * list of all options and their values. * * Results: * A standard Tcl result. The value of the specified option or a * list of all options and their values is returned in the * supplied DString. * * Side effects: * None. * *------------------------------------------------------------------- */ static int TlsGetOptionProc(ClientData instanceData, /* Socket state. */ Tcl_Interp *interp, /* For errors - can be NULL. */ CONST84 char *optionName, /* Name of the option to * retrieve the value for, or * NULL to get all options and * their values. */ Tcl_DString *dsPtr) /* Where to store the computed value * initialized by caller. */ { State *statePtr = (State *) instanceData; Tcl_Channel downChan = Tls_GetParent(statePtr, TLS_TCL_FASTPATH); Tcl_DriverGetOptionProc *getOptionProc; getOptionProc = Tcl_ChannelGetOptionProc(Tcl_GetChannelType(downChan)); if (getOptionProc != NULL) { return (*getOptionProc)(Tcl_GetChannelInstanceData(downChan), interp, optionName, dsPtr); } else if (optionName == (char*) NULL) { /* * Request is query for all options, this is ok. */ return TCL_OK; } /* * Request for a specific option has to fail, we don't have any. */ return TCL_ERROR; } /* *------------------------------------------------------------------- * * TlsWatchProc -- * * Initialize the notifier to watch Tcl_Files from this channel. * * Results: * None. * * Side effects: * Sets up the notifier so that a future event on the channel * will be seen by Tcl. * *------------------------------------------------------------------- */ static void TlsWatchProc(ClientData instanceData, /* The socket state. */ int mask) /* Events of interest; an OR-ed * combination of TCL_READABLE, * TCL_WRITABLE and TCL_EXCEPTION. */ { Tcl_Channel downChan; State *statePtr = (State *) instanceData; dprintf("TlsWatchProc(0x%x)", mask); /* Pretend to be dead as long as the verify callback is running. * Otherwise that callback could be invoked recursively. */ if (statePtr->flags & TLS_TCL_CALLBACK) { dprintf("Callback is on-going, doing nothing"); return; } dprintFlags(statePtr); downChan = Tls_GetParent(statePtr, TLS_TCL_FASTPATH); if (statePtr->flags & TLS_TCL_HANDSHAKE_FAILED) { dprintf("Asked to watch a socket with a failed handshake -- nothing can happen here"); dprintf("Unregistering interest in the lower channel"); (Tcl_GetChannelType(downChan))->watchProc(Tcl_GetChannelInstanceData(downChan), 0); statePtr->watchMask = 0; return; } statePtr->watchMask = mask; /* No channel handlers any more. We will be notified automatically * about events on the channel below via a call to our * 'TransformNotifyProc'. But we have to pass the interest down now. * We are allowed to add additional 'interest' to the mask if we want * to. But this transformation has no such interest. It just passes * the request down, unchanged. */ dprintf("Registering our interest in the lower channel (chan=%p)", (void *) downChan); (Tcl_GetChannelType(downChan)) ->watchProc(Tcl_GetChannelInstanceData(downChan), mask); /* * Management of the internal timer. */ if (statePtr->timer != (Tcl_TimerToken) NULL) { dprintf("A timer was found, deleting it"); Tcl_DeleteTimerHandler(statePtr->timer); statePtr->timer = (Tcl_TimerToken) NULL; } if ((mask & TCL_READABLE) && Tcl_InputBuffered(statePtr->self) > 0) { /* * There is interest in readable events and we actually have * data waiting, so generate a timer to flush that. */ dprintf("Creating a new timer since data appears to be waiting"); statePtr->timer = Tcl_CreateTimerHandler(TLS_TCL_DELAY, TlsChannelHandlerTimer, (ClientData) statePtr); } } /* *------------------------------------------------------------------- * * TlsGetHandleProc -- * * Called from Tcl_GetChannelFile to retrieve o/s file handler * from the SSL socket based channel. * * Results: * The appropriate Tcl_File or NULL if not present. * * Side effects: * None. * *------------------------------------------------------------------- */ static int TlsGetHandleProc(ClientData instanceData, int direction, ClientData *handlePtr) { State *statePtr = (State *) instanceData; return(Tcl_GetChannelHandle(Tls_GetParent(statePtr, TLS_TCL_FASTPATH), direction, handlePtr)); } /* *------------------------------------------------------------------- * * TlsNotifyProc -- * * Handler called by Tcl to inform us of activity * on the underlying channel. * * Results: * None. * * Side effects: * May process the incoming event by itself. * *------------------------------------------------------------------- */ static int TlsNotifyProc(ClientData instanceData, int mask) { State *statePtr = (State *) instanceData; int errorCode; /* * An event occured in the underlying channel. This * transformation doesn't process such events thus returns the * incoming mask unchanged. */ if (statePtr->timer != (Tcl_TimerToken) NULL) { /* * Delete an existing timer. It was not fired, yet we are * here, so the channel below generated such an event and we * don't have to. The renewal of the interest after the * execution of channel handlers will eventually cause us to * recreate the timer (in WatchProc). */ Tcl_DeleteTimerHandler(statePtr->timer); statePtr->timer = (Tcl_TimerToken) NULL; } if (statePtr->flags & TLS_TCL_CALLBACK) { dprintf("Returning 0 due to callback"); return 0; } dprintf("Calling Tls_WaitForConnect"); errorCode = 0; if (Tls_WaitForConnect(statePtr, &errorCode) < 0) { if (errorCode == EAGAIN) { dprintf("Async flag could be set (didn't check) and errorCode == EAGAIN: Returning 0"); return 0; } dprintf("Tls_WaitForConnect returned an error"); } dprintf("Returning %i", mask); return(mask); } #if 0 /* *------------------------------------------------------* * * TlsChannelHandler -- * * ------------------------------------------------* * Handler called by Tcl as a result of * Tcl_CreateChannelHandler - to inform us of activity * on the underlying channel. * ------------------------------------------------* * * Sideeffects: * May generate subsequent calls to * Tcl_NotifyChannel. * * Result: * None. * *------------------------------------------------------* */ static void TlsChannelHandler (clientData, mask) ClientData clientData; int mask; { State *statePtr = (State *) clientData; dprintf("HANDLER(0x%x)", mask); Tcl_Preserve( (ClientData)statePtr); if (mask & TCL_READABLE) { BIO_set_flags(statePtr->p_bio, BIO_FLAGS_READ); } else { BIO_clear_flags(statePtr->p_bio, BIO_FLAGS_READ); } if (mask & TCL_WRITABLE) { BIO_set_flags(statePtr->p_bio, BIO_FLAGS_WRITE); } else { BIO_clear_flags(statePtr->p_bio, BIO_FLAGS_WRITE); } mask = 0; if (BIO_wpending(statePtr->bio)) { mask |= TCL_WRITABLE; } if (BIO_pending(statePtr->bio)) { mask |= TCL_READABLE; } /* * The following NotifyChannel calls seems to be important, but * we don't know why. It looks like if the mask is ever non-zero * that it will enter an infinite loop. * * Notify the upper channel of the current BIO state so the event * continues to propagate up the chain. * * stanton: It looks like this could result in an infinite loop if * the upper channel doesn't cause ChannelHandler to be removed * before Tcl_NotifyChannel calls channel handlers on the lower channel. */ Tcl_NotifyChannel(statePtr->self, mask); if (statePtr->timer != (Tcl_TimerToken)NULL) { Tcl_DeleteTimerHandler(statePtr->timer); statePtr->timer = (Tcl_TimerToken)NULL; } if ((mask & TCL_READABLE) && Tcl_InputBuffered(statePtr->self) > 0) { /* * Data is waiting, flush it out in short time */ statePtr->timer = Tcl_CreateTimerHandler(TLS_TCL_DELAY, TlsChannelHandlerTimer, (ClientData) statePtr); } Tcl_Release( (ClientData)statePtr); } #endif /* *------------------------------------------------------* * * TlsChannelHandlerTimer -- * * ------------------------------------------------* * Called by the notifier (-> timer) to flush out * information waiting in channel buffers. * ------------------------------------------------* * * Sideeffects: * As of 'TlsChannelHandler'. * * Result: * None. * *------------------------------------------------------* */ static void TlsChannelHandlerTimer(ClientData clientData) { State *statePtr = (State *) clientData; int mask = 0; dprintf("Called"); statePtr->timer = (Tcl_TimerToken) NULL; if (BIO_wpending(statePtr->bio)) { dprintf("[chan=%p] BIO writable", statePtr->self); mask |= TCL_WRITABLE; } if (BIO_pending(statePtr->bio)) { dprintf("[chan=%p] BIO readable", statePtr->self); mask |= TCL_READABLE; } dprintf("Notifying ourselves"); Tcl_NotifyChannel(statePtr->self, mask); dprintf("Returning"); return; } /* *------------------------------------------------------* * * Tls_WaitForConnect -- * * Sideeffects: * Issues SSL_accept or SSL_connect * * Result: * None. * *------------------------------------------------------* */ int Tls_WaitForConnect(State *statePtr, int *errorCodePtr) { unsigned long backingError; int err, rc; int bioShouldRetry; dprintf("WaitForConnect(%p)", (void *) statePtr); dprintFlags(statePtr); if (!(statePtr->flags & TLS_TCL_INIT)) { dprintf("Tls_WaitForConnect called on already initialized channel -- returning with immediate success"); *errorCodePtr = 0; return(0); } if (statePtr->flags & TLS_TCL_HANDSHAKE_FAILED) { /* * We choose ECONNRESET over ECONNABORTED here because some server * side code, on the wiki for example, sets up a read handler that * does a read and if eof closes the channel. There is no catch/try * around the reads so exceptions will result in potentially many * dangling channels hanging around that should have been closed. * (Backgroun: ECONNABORTED maps to a Tcl exception and * ECONNRESET maps to graceful EOF). */ *errorCodePtr = ECONNRESET; return(-1); } for (;;) { /* Not initialized yet! */ if (statePtr->flags & TLS_TCL_SERVER) { dprintf("Calling SSL_accept()"); err = SSL_accept(statePtr->ssl); } else { dprintf("Calling SSL_connect()"); err = SSL_connect(statePtr->ssl); } if (err > 0) { dprintf("That seems to have gone okay"); BIO_flush(statePtr->bio); } rc = SSL_get_error(statePtr->ssl, err); dprintf("Got error: %i (rc = %i)", err, rc); bioShouldRetry = 0; if (err <= 0) { if (rc == SSL_ERROR_WANT_CONNECT || rc == SSL_ERROR_WANT_ACCEPT || rc == SSL_ERROR_WANT_READ || rc == SSL_ERROR_WANT_WRITE) { bioShouldRetry = 1; } else if (BIO_should_retry(statePtr->bio)) { bioShouldRetry = 1; } } else { if (!SSL_is_init_finished(statePtr->ssl)) { bioShouldRetry = 1; } } if (bioShouldRetry) { dprintf("The I/O did not complete -- but we should try it again"); if (statePtr->flags & TLS_TCL_ASYNC) { dprintf("Returning EAGAIN so that it can be retried later"); *errorCodePtr = EAGAIN; return(-1); } else { dprintf("Doing so now"); continue; } } dprintf("We have either completely established the session or completely failed it -- there is no more need to ever retry it though"); break; } *errorCodePtr = EINVAL; switch (rc) { case SSL_ERROR_NONE: /* The connection is up, we are done here */ dprintf("The connection is up"); break; case SSL_ERROR_ZERO_RETURN: dprintf("SSL_ERROR_ZERO_RETURN: Connect returned an invalid value...") return(-1); case SSL_ERROR_SYSCALL: backingError = ERR_get_error(); dprintf("I/O error occured"); if (backingError == 0 && err == 0) { dprintf("EOF reached") } statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED; *errorCodePtr = ECONNRESET; return(-1); case SSL_ERROR_SSL: dprintf("Got permanent fatal SSL error, aborting immediately"); Tls_Error(statePtr, (char *)ERR_reason_error_string(ERR_get_error())); statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED; *errorCodePtr = ECONNABORTED; return(-1); case SSL_ERROR_WANT_CONNECT: case SSL_ERROR_WANT_ACCEPT: case SSL_ERROR_WANT_X509_LOOKUP: default: dprintf("We got a confusing reply: %i", rc); *errorCodePtr = Tcl_GetErrno(); dprintf("ERR(%d, %d) ", rc, *errorCodePtr); return(-1); } #if 0 if (statePtr->flags & TLS_TCL_SERVER) { dprintf("This is an TLS server, checking the certificate for the peer"); err = SSL_get_verify_result(statePtr->ssl); if (err != X509_V_OK) { dprintf("Invalid certificate, returning in failure"); Tls_Error(statePtr, (char *)X509_verify_cert_error_string(err)); statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED; *errorCodePtr = ECONNABORTED; return(-1); } } #endif dprintf("Removing the \"TLS_TCL_INIT\" flag since we have completed the handshake"); statePtr->flags &= ~TLS_TCL_INIT; dprintf("Returning in success"); *errorCodePtr = 0; return(0); } Tcl_Channel Tls_GetParent(State *statePtr, int maskFlags) { dprintf("Requested to get parent of channel %p", statePtr->self); if ((statePtr->flags & ~maskFlags) & TLS_TCL_FASTPATH) { dprintf("Asked to get the parent channel while we are using FastPath -- returning NULL"); return(NULL); } return(Tcl_GetStackedChannel(statePtr->self)); }