Check-in [77e904c4e2]
Bounty program for improvements to Tcl and certain Tcl packages.
Overview
Comment:Rewrote state engine for OpenSSL connection establishment to be more easily reasoned about
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | wip-fix-io-layer
Files: files | file ages | folders
SHA1: 77e904c4e2aa6f61cdf0a1e64124b290851f88bc
User & Date: rkeene on 2016-12-11 21:22:09
Other Links: branch diff | manifest | tags
Context
2016-12-11
23:57
Added a flag for fastpath so that errors can be found while using it check-in: 8b2b046ff5 user: rkeene tags: wip-fix-io-layer
21:22
Rewrote state engine for OpenSSL connection establishment to be more easily reasoned about check-in: 77e904c4e2 user: rkeene tags: wip-fix-io-layer
20:05
Fixed pass-through to fetch file descriptor using a pointer check-in: b5ba86f2be user: rkeene tags: wip-fix-io-layer
Changes

Modified tlsIO.c from [0aabed0fd6] to [320c969bcc].

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     * 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);
    dprintBuffer(buf, bytesRead);

    if (bytesRead <= 0) {
	int err = SSL_get_error(statePtr->ssl, bytesRead);

	if (err == SSL_ERROR_SSL) {
	    Tls_Error(statePtr, TCLTLS_SSL_ERROR(statePtr->ssl, bytesRead));
	    *errorCodePtr = ECONNABORTED;
	} else if (BIO_should_retry(statePtr->bio)) {
	    dprintf("retry based on EAGAIN");
	    *errorCodePtr = EAGAIN;
	} else {
	    *errorCodePtr = Tcl_GetErrno();
	    if (*errorCodePtr == ECONNRESET) {
	    if (*errorCodePtr == ECONNRESET || bytesRead < 0) {
		/* Soft EOF */
		*errorCodePtr = 0;
		bytesRead = 0;
	    } else {
                dprintf("Got an unexpected error: %i", *errorCodePtr);
            }
	}
    } else {
        dprintBuffer(buf, bytesRead);
    }
    input:
    dprintf("Input(%d) -> %d [%d]", bufSize, bytesRead, *errorCodePtr);
    return bytesRead;
}

/*
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 *
 *	Result:
 *		None.
 *
 *------------------------------------------------------*
 */
int Tls_WaitForConnect(State *statePtr, int *errorCodePtr) {
	unsigned long backingError;
    int err;
	int err, rc;
	int bioShouldRetry;

    dprintf("WaitForConnect(%p)", (void *) statePtr);
	dprintf("WaitForConnect(%p)", (void *) statePtr);
	dprintFlags(statePtr);

	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) {
				bioShouldRetry = 1;
			} else if (BIO_should_retry(statePtr->bio)) {
				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_WANT_READ:
		case SSL_ERROR_WANT_WRITE:
			dprintf("SSL_ERROR_WANT read/write -- not sure what to do here");

			return(-1);
		case SSL_ERROR_SYSCALL:
			backingError = ERR_get_error();
			dprintf("I/O error occured");

    if (statePtr->flags & TLS_TCL_HANDSHAKE_FAILED) {
			if (backingError == 0 && err == 0) {
        /*
         * 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;
				dprintf("EOF reached")
			}

			statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED;
			*errorCodePtr = ECONNRESET;
			return(-1);
    }

		case SSL_ERROR_SSL:
    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);
			dprintf("Got permenant 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);
	}

	/*SSL_write(statePtr->ssl, (char*)&err, 0);	HACK!!! */
	if (err > 0) {
            dprintf("That seems to have gone okay");
	    BIO_flush(statePtr->bio);
	} else {
	    int rc = SSL_get_error(statePtr->ssl, err);

	if (statePtr->flags & TLS_TCL_SERVER) {
            dprintf("Got error: %i (rc = %i)", err, rc);
		dprintf("This is an TLS server, checking the certificate for the peer");

	    if (rc == SSL_ERROR_SSL) {
		Tls_Error(statePtr,
			(char *)ERR_reason_error_string(ERR_get_error()));
                statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED;
		*errorCodePtr = ECONNABORTED;
		return -1;
	    } else if (BIO_should_retry(statePtr->bio)) {
		if (statePtr->flags & TLS_TCL_ASYNC) {
		    dprintf("E! ");
		    *errorCodePtr = EAGAIN;
		    return -1;
		} else {
		    continue;
		}
	    } else if (err <= 0) {
                if (SSL_in_init(statePtr->ssl)) {
                    dprintf("SSL_in_init() is true");
                }

                if (Tcl_Eof(statePtr->self)) {
                    dprintf("Error = 0 and EOF is set");

                    if (rc != SSL_ERROR_SYSCALL) {
                        dprintf("Error from some reason other than our BIO, returning 0");
                        return 0;
                    }
                }
		dprintf("CR! ");
                statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED;
		*errorCodePtr = ECONNRESET;
		return -1;
	    }
	    if (statePtr->flags & TLS_TCL_SERVER) {
		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;

			Tls_Error(statePtr, (char *)X509_verify_cert_error_string(err));
			statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED;
			*errorCodePtr = ECONNABORTED;
			return(-1);
		}
	    }
	}
	    *errorCodePtr = Tcl_GetErrno();
	    dprintf("ERR(%d, %d) ", rc, *errorCodePtr);
	    return -1;
	}

	dprintf("R0! ");
	return 1;
	*errorCodePtr = 0;
	return(0);
    }
}

Tcl_Channel Tls_GetParent(State *statePtr) {
	dprintf("Requested to get parent of channel %p", statePtr->self);

	return(Tcl_GetStackedChannel(statePtr->self));
}