easy-tls.c

Openssl 0.9.8e 最新版OpenSSL

	int w = n >= 2;
	/* loop over all (i, w) in {0,1}x{0,1} */
	int fd;
	
	if (i == 0 && w == 0)
	    fd = read_select_1;
	else if (i == 1 && w == 0)
	    fd = read_select_2;
	else if (i == 0 && w == 1)
	    fd = write_select_1;
	else {
	    assert(i == 1 && w == 1);
	    fd = write_select_2;
	}
	
	if (fd >= 0) {
	    if (w == 0)
		FD_SET(fd, &reads);
	    else /* w == 1 */
		FD_SET(fd, &writes);
	}
    }

    if (seconds >= 0) {
	timeout.tv_sec = seconds;
	timeout.tv_usec = 0;
	timeout_p = &timeout;
    } else 
	timeout_p = NULL;

    DEBUG_MSG2("select no.", ++tls_select_count);
    select(maxfd + 1, &reads, &writes, (fd_set *) NULL, timeout_p);
    DEBUG_MSG("cont.");
}

/*****************************************************************************/

#define TUNNELBUFSIZE (16*1024)
struct tunnelbuf {
    char buf[TUNNELBUFSIZE];
    size_t len;
    size_t offset;
};

static int tls_connect_attempt(SSL *, int *write_select, int *read_select, int *closed, int *progress, const char **err_pref);

static int tls_accept_attempt(SSL *, int *write_select, int *read_select, int *closed, int *progress, const char **err_pref);

static int tls_write_attempt(SSL *, struct tunnelbuf *, int *write_select, int *read_select, int *closed, int *progress, const char **err_pref);

static int tls_read_attempt(SSL *, struct tunnelbuf *, int *write_select, int *read_select, int *closed, int *progress, const char **err_pref);

static int write_attempt(int fd, struct tunnelbuf *, int *select, int *closed, int *progress);

static int read_attempt(int fd, struct tunnelbuf *, int *select, int *closed, int *progress);

static void write_info(SSL *ssl, int *info_fd)
{
    if (*info_fd != -1) {
	long v;
	int v_ok;
	struct tls_x509_name_string peer;
	char infobuf[TLS_INFO_SIZE];
	int r;

	DEBUG_MSG("write_info");
	v = SSL_get_verify_result(ssl);
	v_ok = (v == X509_V_OK) ? 'A' : 'E'; /* Auth./Error */
	{
	    X509 *peercert;

	    peercert = SSL_get_peer_certificate(ssl);
	    tls_get_x509_subject_name_oneline(peercert, &peer);
	    if (peercert != NULL)
		X509_free(peercert);
	}
	if (peer.str[0] == '\0')
	    v_ok = '0'; /* no cert at all */
	else
	    if (strchr(peer.str, '\n')) {
		/* should not happen, but make sure */
		*strchr(peer.str, '\n') = '\0';
	    }
	r = snprintf(infobuf, sizeof infobuf, "%c:%s\n%s\n", v_ok, X509_verify_cert_error_string(v), peer.str);
	DEBUG_MSG2("snprintf", r);
	if (r == -1 || r >= sizeof infobuf)
	    r = sizeof infobuf - 1;
	write(*info_fd, infobuf, r);
	close (*info_fd);
	*info_fd = -1;
    }
}


/* tls_proxy expects that all fds are closed after return */
static void
tls_proxy(int clear_fd, int tls_fd, int info_fd, SSL_CTX *ctx, int client_p)
{
    struct tunnelbuf clear_to_tls, tls_to_clear;
    SSL *ssl;
    BIO *rbio, *wbio;
    int closed, in_handshake;
    const char *err_pref_1 = "", *err_pref_2 = "";
    const char *err_def = NULL;

    assert(clear_fd != -1);
    assert(tls_fd != -1);
    assert(clear_fd < FD_SETSIZE);
    assert(tls_fd < FD_SETSIZE);
    /* info_fd may be -1 */
    assert(ctx != NULL);

    tls_rand_seed_uniquely();

    tls_socket_nonblocking(clear_fd);
    DEBUG_MSG2("clear_fd", clear_fd);
    tls_socket_nonblocking(tls_fd);
    DEBUG_MSG2("tls_fd", tls_fd);

    ssl = SSL_new(ctx);
    if (ssl == NULL)
	goto err;
    DEBUG_MSG("SSL_new");
    if (!SSL_set_fd(ssl, tls_fd))
	goto err;
    rbio = SSL_get_rbio(ssl);
    wbio = SSL_get_wbio(ssl); /* should be the same, but who cares */
    assert(rbio != NULL);
    assert(wbio != NULL);
    if (client_p)
	SSL_set_connect_state(ssl);
    else
	SSL_set_accept_state(ssl);
    
    closed = 0;
    in_handshake = 1;
    tls_to_clear.len = 0;
    tls_to_clear.offset = 0;
    clear_to_tls.len = 0;
    clear_to_tls.offset = 0;

    err_def = "I/O error";
    
    /* loop finishes as soon as we detect that one side closed;
     * when all (program and OS) buffers have enough space,
     * the data from the last succesful read in each direction is transferred
     * before close */
    do {
	int clear_read_select = 0, clear_write_select = 0,
	    tls_read_select = 0, tls_write_select = 0,
	    progress = 0;
	int r;
	unsigned long num_read = BIO_number_read(rbio),
	    num_written = BIO_number_written(wbio);

	DEBUG_MSG2("loop iteration", ++tls_loop_count);

	if (in_handshake) {
	    DEBUG_MSG("in_handshake");
	    if (client_p)
		r = tls_connect_attempt(ssl, &tls_write_select, &tls_read_select, &closed, &progress, &err_pref_1);
	    else
		r = tls_accept_attempt(ssl, &tls_write_select, &tls_read_select, &closed, &progress, &err_pref_1);
	    if (r != 0) {
		write_info(ssl, &info_fd);
		goto err;
	    }
	    if (closed)
		goto err_return;
	    if (!SSL_in_init(ssl)) {
		in_handshake = 0;
		write_info(ssl, &info_fd);
	    }
	}
	
	if (clear_to_tls.len != 0 && !in_handshake) {
	    assert(!closed);
	    
	    r = tls_write_attempt(ssl, &clear_to_tls, &tls_write_select, &tls_read_select, &closed, &progress, &err_pref_1);
	    if (r != 0)
		goto err;
	    if (closed) {
		assert(progress);
		tls_to_clear.offset = 0;
		tls_to_clear.len = 0;
	    }
	}
	
	if (tls_to_clear.len != 0) {
	    assert(!closed);

	    r = write_attempt(clear_fd, &tls_to_clear, &clear_write_select, &closed, &progress);
	    if (r != 0)
		goto err_return;
	    if (closed) {
		assert(progress);
		clear_to_tls.offset = 0;
		clear_to_tls.len = 0;
	    }
	}
	
	if (!closed) {
	    if (clear_to_tls.offset + clear_to_tls.len < sizeof clear_to_tls.buf) {
		r = read_attempt(clear_fd, &clear_to_tls, &clear_read_select, &closed, &progress);
		if (r != 0)
		    goto err_return;
		if (closed) {
		    r = SSL_shutdown(ssl);
		    DEBUG_MSG2("SSL_shutdown", r);
		}
	    }
	}
	
	if (!closed && !in_handshake) {
	    if (tls_to_clear.offset + tls_to_clear.len < sizeof tls_to_clear.buf) {
		r = tls_read_attempt(ssl, &tls_to_clear, &tls_write_select, &tls_read_select, &closed, &progress, &err_pref_1);
		if (r != 0)
		    goto err;
		if (closed) {
		    r = SSL_shutdown(ssl);
		    DEBUG_MSG2("SSL_shutdown", r);
		}
	    }
	}

	if (!progress) {
	    DEBUG_MSG("!progress?");
	    if (num_read != BIO_number_read(rbio) || num_written != BIO_number_written(wbio))
		progress = 1;

	    if (!progress) {
		DEBUG_MSG("!progress");
		assert(clear_read_select || tls_read_select || clear_write_select || tls_write_select);
		tls_sockets_select(clear_read_select ? clear_fd : -1, tls_read_select ? tls_fd : -1, clear_write_select ? clear_fd : -1, tls_write_select ? tls_fd : -1, -1);
	    }
	}
    } while (!closed);
    return;

 err:
    tls_openssl_errors(err_pref_1, err_pref_2, err_def, tls_child_apparg);
 err_return:
    return;
}


static int
tls_get_error(SSL *ssl, int r, int *write_select, int *read_select, int *closed, int *progress)
{
    int err = SSL_get_error(ssl, r);

    if (err == SSL_ERROR_NONE) {
	assert(r > 0);
	*progress = 1;
	return 0;
    }

    assert(r <= 0);

    switch (err) {
    case SSL_ERROR_ZERO_RETURN:
	assert(r == 0);
	*closed = 1;
	*progress = 1;
	return 0;

    case SSL_ERROR_WANT_WRITE:
	*write_select = 1;
	return 0;
	
    case SSL_ERROR_WANT_READ:
	*read_select = 1;
	return 0;
    }

    return -1;
}

static int
tls_connect_attempt(SSL *ssl, int *write_select, int *read_select, int *closed, int *progress, const char **err_pref)
{
    int n, r;

    DEBUG_MSG("tls_connect_attempt");
    n = SSL_connect(ssl);
    DEBUG_MSG2("SSL_connect",n);
    r = tls_get_error(ssl, n, write_select, read_select, closed, progress);
    if (r == -1)
	*err_pref = " during SSL_connect";
    return r;
}

static int
tls_accept_attempt(SSL *ssl, int *write_select, int *read_select, int *closed, int *progress, const char **err_pref)
{
    int n, r;

    DEBUG_MSG("tls_accept_attempt");
    n = SSL_accept(ssl);
    DEBUG_MSG2("SSL_accept",n);
    r = tls_get_error(ssl, n, write_select, read_select, closed, progress);
    if (r == -1)
	*err_pref = " during SSL_accept";
    return r;
}

static int
tls_write_attempt(SSL *ssl, struct tunnelbuf *buf, int *write_select, int *read_select, int *closed, int *progress, const char **err_pref)
{
    int n, r;

    DEBUG_MSG("tls_write_attempt");
    n = SSL_write(ssl, buf->buf + buf->offset, buf->len);
    DEBUG_MSG2("SSL_write",n);
    r = tls_get_error(ssl, n, write_select, read_select, closed, progress);
    if (n > 0) {
	buf->len -= n;
	assert(buf->len >= 0);
	if (buf->len == 0)
	    buf->offset = 0;
	else
	    buf->offset += n;
    }
    if (r == -1)
	*err_pref = " during SSL_write";
    return r;
}

static int
tls_read_attempt(SSL *ssl, struct tunnelbuf *buf, int *write_select, int *read_select, int *closed, int *progress, const char **err_pref)
{
    int n, r;
    size_t total;

    DEBUG_MSG("tls_read_attempt");
    total = buf->offset + buf->len;
    assert(total < sizeof buf->buf);
    n = SSL_read(ssl, buf->buf + total, (sizeof buf->buf) - total);
    DEBUG_MSG2("SSL_read",n);
    r = tls_get_error(ssl, n, write_select, read_select, closed, progress);
    if (n > 0) {
	buf->len += n;
	assert(buf->offset + buf->len <= sizeof buf->buf);
    }
    if (r == -1)
	*err_pref = " during SSL_read";
    return r;
}

static int
get_error(int r, int *select, int *closed, int *progress)
{
    if (r >= 0) {
	*progress = 1;
	if (r == 0)
	    *closed = 1;
	return 0;
    } else {
	assert(r == -1);
	if (errno == EAGAIN || errno == EWOULDBLOCK) {
	    *select = 1;
	    return 0;
	} else if (errno == EPIPE) {
	    *progress = 1;
	    *closed = 1;
	    return 0;
	} else
	    return -1;
    }
}

static int write_attempt(int fd, struct tunnelbuf *buf, int *select, int *closed, int *progress)
{
    int n, r;

    DEBUG_MSG("write_attempt");
    n = write(fd, buf->buf + buf->offset, buf->len);
    DEBUG_MSG2("write",n);
    r = get_error(n, select, closed, progress);
    if (n > 0) {
	buf->len -= n;
	assert(buf->len >= 0);
	if (buf->len == 0)
	    buf->offset = 0;
	else
	    buf->offset += n;
    }
    if (r == -1)
	tls_errprintf(1, tls_child_apparg, "write error: %s\n", strerror(errno));
    return r;
}
    
static int
read_attempt(int fd, struct tunnelbuf *buf, int *select, int *closed, int *progress)
{
    int n, r;
    size_t total;

    DEBUG_MSG("read_attempt");
    total = buf->offset + buf->len;
    assert(total < sizeof buf->buf);
    n = read(fd, buf->buf + total, (sizeof buf->buf) - total);
    DEBUG_MSG2("read",n);
    r = get_error(n, select, closed, progress);
    if (n > 0) {
	buf->len += n;
	assert(buf->offset + buf->len <= sizeof buf->buf);
    }
    if (r == -1)
	tls_errprintf(1, tls_child_apparg, "read error: %s\n", strerror(errno));
    return r;
}