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/*
* Copyright (c) 2008, 2009, 2010, 2011 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <config.h>
#include "stream-ssl.h"
#include "dhparams.h"
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <inttypes.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/tcp.h>
#include <openssl/err.h>
#include <openssl/ssl.h>
#include <openssl/x509v3.h>
#include <poll.h>
#include <sys/fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#include "coverage.h"
#include "dynamic-string.h"
#include "leak-checker.h"
#include "ofpbuf.h"
#include "openflow/openflow.h"
#include "packets.h"
#include "poll-loop.h"
#include "shash.h"
#include "socket-util.h"
#include "util.h"
#include "stream-provider.h"
#include "stream.h"
#include "timeval.h"
#include "vlog.h"
VLOG_DEFINE_THIS_MODULE(stream_ssl);
/* Active SSL. */
enum ssl_state {
STATE_TCP_CONNECTING,
STATE_SSL_CONNECTING
};
enum session_type {
CLIENT,
SERVER
};
struct ssl_stream
{
struct stream stream;
enum ssl_state state;
enum session_type type;
int fd;
SSL *ssl;
struct ofpbuf *txbuf;
unsigned int session_nr;
/* rx_want and tx_want record the result of the last call to SSL_read()
* and SSL_write(), respectively:
*
* - If the call reported that data needed to be read from the file
* descriptor, the corresponding member is set to SSL_READING.
*
* - If the call reported that data needed to be written to the file
* descriptor, the corresponding member is set to SSL_WRITING.
*
* - Otherwise, the member is set to SSL_NOTHING, indicating that the
* call completed successfully (or with an error) and that there is no
* need to block.
*
* These are needed because there is no way to ask OpenSSL what a data read
* or write would require without giving it a buffer to receive into or
* data to send, respectively. (Note that the SSL_want() status is
* overwritten by each SSL_read() or SSL_write() call, so we can't rely on
* its value.)
*
* A single call to SSL_read() or SSL_write() can perform both reading
* and writing and thus invalidate not one of these values but actually
* both. Consider this situation, for example:
*
* - SSL_write() blocks on a read, so tx_want gets SSL_READING.
*
* - SSL_read() laters succeeds reading from 'fd' and clears out the
* whole receive buffer, so rx_want gets SSL_READING.
*
* - Client calls stream_wait(STREAM_RECV) and stream_wait(STREAM_SEND)
* and blocks.
*
* - Now we're stuck blocking until the peer sends us data, even though
* SSL_write() could now succeed, which could easily be a deadlock
* condition.
*
* On the other hand, we can't reset both tx_want and rx_want on every call
* to SSL_read() or SSL_write(), because that would produce livelock,
* e.g. in this situation:
*
* - SSL_write() blocks, so tx_want gets SSL_READING or SSL_WRITING.
*
* - SSL_read() blocks, so rx_want gets SSL_READING or SSL_WRITING,
* but tx_want gets reset to SSL_NOTHING.
*
* - Client calls stream_wait(STREAM_RECV) and stream_wait(STREAM_SEND)
* and blocks.
*
* - Client wakes up immediately since SSL_NOTHING in tx_want indicates
* that no blocking is necessary.
*
* The solution we adopt here is to set tx_want to SSL_NOTHING after
* calling SSL_read() only if the SSL state of the connection changed,
* which indicates that an SSL-level renegotiation made some progress, and
* similarly for rx_want and SSL_write(). This prevents both the
* deadlock and livelock situations above.
*/
int rx_want, tx_want;
/* A few bytes of header data in case SSL negotiation fails. */
uint8_t head[2];
short int n_head;
};
/* SSL context created by ssl_init(). */
static SSL_CTX *ctx;
struct ssl_config_file {
bool read; /* Whether the file was successfully read. */
char *file_name; /* Configured file name, if any. */
struct timespec mtime; /* File mtime as of last time we read it. */
};
/* SSL configuration files. */
static struct ssl_config_file private_key;
static struct ssl_config_file certificate;
static struct ssl_config_file ca_cert;
/* Ordinarily, the SSL client and server verify each other's certificates using
* a CA certificate. Setting this to false disables this behavior. (This is a
* security risk.) */
static bool verify_peer_cert = true;
/* Ordinarily, we require a CA certificate for the peer to be locally
* available. We can, however, bootstrap the CA certificate from the peer at
* the beginning of our first connection then use that certificate on all
* subsequent connections, saving it to a file for use in future runs also. In
* this case, 'bootstrap_ca_cert' is true. */
static bool bootstrap_ca_cert;
/* Session number. Used in debug logging messages to uniquely identify a
* session. */
static unsigned int next_session_nr;
/* Who knows what can trigger various SSL errors, so let's throttle them down
* quite a bit. */
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 25);
static int ssl_init(void);
static int do_ssl_init(void);
static bool ssl_wants_io(int ssl_error);
static void ssl_close(struct stream *);
static void ssl_clear_txbuf(struct ssl_stream *);
static void interpret_queued_ssl_error(const char *function);
static int interpret_ssl_error(const char *function, int ret, int error,
int *want);
static DH *tmp_dh_callback(SSL *ssl, int is_export OVS_UNUSED, int keylength);
static void log_ca_cert(const char *file_name, X509 *cert);
static void stream_ssl_set_ca_cert_file__(const char *file_name,
bool bootstrap, bool force);
static void ssl_protocol_cb(int write_p, int version, int content_type,
const void *, size_t, SSL *, void *sslv_);
static bool update_ssl_config(struct ssl_config_file *, const char *file_name);
static short int
want_to_poll_events(int want)
{
switch (want) {
case SSL_NOTHING:
NOT_REACHED();
case SSL_READING:
return POLLIN;
case SSL_WRITING:
return POLLOUT;
default:
NOT_REACHED();
}
}
static int
new_ssl_stream(const char *name, int fd, enum session_type type,
enum ssl_state state, const struct sockaddr_in *remote,
struct stream **streamp)
{
struct sockaddr_in local;
socklen_t local_len = sizeof local;
struct ssl_stream *sslv;
SSL *ssl = NULL;
int on = 1;
int retval;
/* Check for all the needful configuration. */
retval = 0;
if (!private_key.read) {
VLOG_ERR("Private key must be configured to use SSL");
retval = ENOPROTOOPT;
}
if (!certificate.read) {
VLOG_ERR("Certificate must be configured to use SSL");
retval = ENOPROTOOPT;
}
if (!ca_cert.read && verify_peer_cert && !bootstrap_ca_cert) {
VLOG_ERR("CA certificate must be configured to use SSL");
retval = ENOPROTOOPT;
}
if (!SSL_CTX_check_private_key(ctx)) {
VLOG_ERR("Private key does not match certificate public key: %s",
ERR_error_string(ERR_get_error(), NULL));
retval = ENOPROTOOPT;
}
if (retval) {
goto error;
}
/* Get the local IP and port information */
retval = getsockname(fd, (struct sockaddr *) &local, &local_len);
if (retval) {
memset(&local, 0, sizeof local);
}
/* Disable Nagle. */
retval = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof on);
if (retval) {
VLOG_ERR("%s: setsockopt(TCP_NODELAY): %s", name, strerror(errno));
retval = errno;
goto error;
}
/* Create and configure OpenSSL stream. */
ssl = SSL_new(ctx);
if (ssl == NULL) {
VLOG_ERR("SSL_new: %s", ERR_error_string(ERR_get_error(), NULL));
retval = ENOPROTOOPT;
goto error;
}
if (SSL_set_fd(ssl, fd) == 0) {
VLOG_ERR("SSL_set_fd: %s", ERR_error_string(ERR_get_error(), NULL));
retval = ENOPROTOOPT;
goto error;
}
if (!verify_peer_cert || (bootstrap_ca_cert && type == CLIENT)) {
SSL_set_verify(ssl, SSL_VERIFY_NONE, NULL);
}
/* Create and return the ssl_stream. */
sslv = xmalloc(sizeof *sslv);
stream_init(&sslv->stream, &ssl_stream_class, EAGAIN, name);
stream_set_remote_ip(&sslv->stream, remote->sin_addr.s_addr);
stream_set_remote_port(&sslv->stream, remote->sin_port);
stream_set_local_ip(&sslv->stream, local.sin_addr.s_addr);
stream_set_local_port(&sslv->stream, local.sin_port);
sslv->state = state;
sslv->type = type;
sslv->fd = fd;
sslv->ssl = ssl;
sslv->txbuf = NULL;
sslv->rx_want = sslv->tx_want = SSL_NOTHING;
sslv->session_nr = next_session_nr++;
sslv->n_head = 0;
if (VLOG_IS_DBG_ENABLED()) {
SSL_set_msg_callback(ssl, ssl_protocol_cb);
SSL_set_msg_callback_arg(ssl, sslv);
}
*streamp = &sslv->stream;
return 0;
error:
if (ssl) {
SSL_free(ssl);
}
close(fd);
return retval;
}
static struct ssl_stream *
ssl_stream_cast(struct stream *stream)
{
stream_assert_class(stream, &ssl_stream_class);
return CONTAINER_OF(stream, struct ssl_stream, stream);
}
static int
ssl_open(const char *name, char *suffix, struct stream **streamp, uint8_t dscp)
{
struct sockaddr_in sin;
int error, fd;
error = ssl_init();
if (error) {
return error;
}
error = inet_open_active(SOCK_STREAM, suffix, OFP_SSL_PORT, &sin, &fd,
dscp);
if (fd >= 0) {
int state = error ? STATE_TCP_CONNECTING : STATE_SSL_CONNECTING;
return new_ssl_stream(name, fd, CLIENT, state, &sin, streamp);
} else {
VLOG_ERR("%s: connect: %s", name, strerror(error));
return error;
}
}
static int
do_ca_cert_bootstrap(struct stream *stream)
{
struct ssl_stream *sslv = ssl_stream_cast(stream);
STACK_OF(X509) *chain;
X509 *cert;
FILE *file;
int error;
int fd;
chain = SSL_get_peer_cert_chain(sslv->ssl);
if (!chain || !sk_X509_num(chain)) {
VLOG_ERR("could not bootstrap CA cert: no certificate presented by "
"peer");
return EPROTO;
}
cert = sk_X509_value(chain, sk_X509_num(chain) - 1);
/* Check that 'cert' is self-signed. Otherwise it is not a CA
* certificate and we should not attempt to use it as one. */
error = X509_check_issued(cert, cert);
if (error) {
VLOG_ERR("could not bootstrap CA cert: obtained certificate is "
"not self-signed (%s)",
X509_verify_cert_error_string(error));
if (sk_X509_num(chain) < 2) {
VLOG_ERR("only one certificate was received, so probably the peer "
"is not configured to send its CA certificate");
}
return EPROTO;
}
fd = open(ca_cert.file_name, O_CREAT | O_EXCL | O_WRONLY, 0444);
if (fd < 0) {
if (errno == EEXIST) {
VLOG_INFO_RL(&rl, "reading CA cert %s created by another process",
ca_cert.file_name);
stream_ssl_set_ca_cert_file__(ca_cert.file_name, true, true);
return EPROTO;
} else {
VLOG_ERR("could not bootstrap CA cert: creating %s failed: %s",
ca_cert.file_name, strerror(errno));
return errno;
}
}
file = fdopen(fd, "w");
if (!file) {
error = errno;
VLOG_ERR("could not bootstrap CA cert: fdopen failed: %s",
strerror(error));
unlink(ca_cert.file_name);
return error;
}
if (!PEM_write_X509(file, cert)) {
VLOG_ERR("could not bootstrap CA cert: PEM_write_X509 to %s failed: "
"%s", ca_cert.file_name,
ERR_error_string(ERR_get_error(), NULL));
fclose(file);
unlink(ca_cert.file_name);
return EIO;
}
if (fclose(file)) {
error = errno;
VLOG_ERR("could not bootstrap CA cert: writing %s failed: %s",
ca_cert.file_name, strerror(error));
unlink(ca_cert.file_name);
return error;
}
VLOG_INFO("successfully bootstrapped CA cert to %s", ca_cert.file_name);
log_ca_cert(ca_cert.file_name, cert);
bootstrap_ca_cert = false;
ca_cert.read = true;
/* SSL_CTX_add_client_CA makes a copy of cert's relevant data. */
SSL_CTX_add_client_CA(ctx, cert);
/* SSL_CTX_use_certificate() takes ownership of the certificate passed in.
* 'cert' is owned by sslv->ssl, so we need to duplicate it. */
cert = X509_dup(cert);
if (!cert) {
out_of_memory();
}
SSL_CTX_set_cert_store(ctx, X509_STORE_new());
if (SSL_CTX_load_verify_locations(ctx, ca_cert.file_name, NULL) != 1) {
VLOG_ERR("SSL_CTX_load_verify_locations: %s",
ERR_error_string(ERR_get_error(), NULL));
return EPROTO;
}
VLOG_INFO("killing successful connection to retry using CA cert");
return EPROTO;
}
static int
ssl_connect(struct stream *stream)
{
struct ssl_stream *sslv = ssl_stream_cast(stream);
int retval;
switch (sslv->state) {
case STATE_TCP_CONNECTING:
retval = check_connection_completion(sslv->fd);
if (retval) {
return retval;
}
sslv->state = STATE_SSL_CONNECTING;
/* Fall through. */
case STATE_SSL_CONNECTING:
/* Capture the first few bytes of received data so that we can guess
* what kind of funny data we've been sent if SSL negotation fails. */
if (sslv->n_head <= 0) {
sslv->n_head = recv(sslv->fd, sslv->head, sizeof sslv->head,
MSG_PEEK);
}
retval = (sslv->type == CLIENT
? SSL_connect(sslv->ssl) : SSL_accept(sslv->ssl));
if (retval != 1) {
int error = SSL_get_error(sslv->ssl, retval);
if (retval < 0 && ssl_wants_io(error)) {
return EAGAIN;
} else {
int unused;
interpret_ssl_error((sslv->type == CLIENT ? "SSL_connect"
: "SSL_accept"), retval, error, &unused);
shutdown(sslv->fd, SHUT_RDWR);
stream_report_content(sslv->head, sslv->n_head, STREAM_SSL,
THIS_MODULE, stream_get_name(stream));
return EPROTO;
}
} else if (bootstrap_ca_cert) {
return do_ca_cert_bootstrap(stream);
} else if (verify_peer_cert
&& ((SSL_get_verify_mode(sslv->ssl)
& (SSL_VERIFY_NONE | SSL_VERIFY_PEER))
!= SSL_VERIFY_PEER)) {
/* Two or more SSL connections completed at the same time while we
* were in bootstrap mode. Only one of these can finish the
* bootstrap successfully. The other one(s) must be rejected
* because they were not verified against the bootstrapped CA
* certificate. (Alternatively we could verify them against the CA
* certificate, but that's more trouble than it's worth. These
* connections will succeed the next time they retry, assuming that
* they have a certificate against the correct CA.) */
VLOG_ERR("rejecting SSL connection during bootstrap race window");
return EPROTO;
} else {
return 0;
}
}
NOT_REACHED();
}
static void
ssl_close(struct stream *stream)
{
struct ssl_stream *sslv = ssl_stream_cast(stream);
ssl_clear_txbuf(sslv);
/* Attempt clean shutdown of the SSL connection. This will work most of
* the time, as long as the kernel send buffer has some free space and the
* SSL connection isn't renegotiating, etc. That has to be good enough,
* since we don't have any way to continue the close operation in the
* background. */
SSL_shutdown(sslv->ssl);
/* SSL_shutdown() might have signaled an error, in which case we need to
* flush it out of the OpenSSL error queue or the next OpenSSL operation
* will falsely signal an error. */
ERR_clear_error();
SSL_free(sslv->ssl);
close(sslv->fd);
free(sslv);
}
static void
interpret_queued_ssl_error(const char *function)
{
int queued_error = ERR_get_error();
if (queued_error != 0) {
VLOG_WARN_RL(&rl, "%s: %s",
function, ERR_error_string(queued_error, NULL));
} else {
VLOG_ERR_RL(&rl, "%s: SSL_ERROR_SSL without queued error", function);
}
}
static int
interpret_ssl_error(const char *function, int ret, int error,
int *want)
{
*want = SSL_NOTHING;
switch (error) {
case SSL_ERROR_NONE:
VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_NONE", function);
break;
case SSL_ERROR_ZERO_RETURN:
VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_ZERO_RETURN", function);
break;
case SSL_ERROR_WANT_READ:
*want = SSL_READING;
return EAGAIN;
case SSL_ERROR_WANT_WRITE:
*want = SSL_WRITING;
return EAGAIN;
case SSL_ERROR_WANT_CONNECT:
VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_CONNECT", function);
break;
case SSL_ERROR_WANT_ACCEPT:
VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_ACCEPT", function);
break;
case SSL_ERROR_WANT_X509_LOOKUP:
VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_X509_LOOKUP",
function);
break;
case SSL_ERROR_SYSCALL: {
int queued_error = ERR_get_error();
if (queued_error == 0) {
if (ret < 0) {
int status = errno;
VLOG_WARN_RL(&rl, "%s: system error (%s)",
function, strerror(status));
return status;
} else {
VLOG_WARN_RL(&rl, "%s: unexpected SSL connection close",
function);
return EPROTO;
}
} else {
VLOG_WARN_RL(&rl, "%s: %s",
function, ERR_error_string(queued_error, NULL));
break;
}
}
case SSL_ERROR_SSL:
interpret_queued_ssl_error(function);
break;
default:
VLOG_ERR_RL(&rl, "%s: bad SSL error code %d", function, error);
break;
}
return EIO;
}
static ssize_t
ssl_recv(struct stream *stream, void *buffer, size_t n)
{
struct ssl_stream *sslv = ssl_stream_cast(stream);
int old_state;
ssize_t ret;
/* Behavior of zero-byte SSL_read is poorly defined. */
assert(n > 0);
old_state = SSL_get_state(sslv->ssl);
ret = SSL_read(sslv->ssl, buffer, n);
if (old_state != SSL_get_state(sslv->ssl)) {
sslv->tx_want = SSL_NOTHING;
}
sslv->rx_want = SSL_NOTHING;
if (ret > 0) {
return ret;
} else {
int error = SSL_get_error(sslv->ssl, ret);
if (error == SSL_ERROR_ZERO_RETURN) {
return 0;
} else {
return -interpret_ssl_error("SSL_read", ret, error,
&sslv->rx_want);
}
}
}
static void
ssl_clear_txbuf(struct ssl_stream *sslv)
{
ofpbuf_delete(sslv->txbuf);
sslv->txbuf = NULL;
}
static int
ssl_do_tx(struct stream *stream)
{
struct ssl_stream *sslv = ssl_stream_cast(stream);
for (;;) {
int old_state = SSL_get_state(sslv->ssl);
int ret = SSL_write(sslv->ssl, sslv->txbuf->data, sslv->txbuf->size);
if (old_state != SSL_get_state(sslv->ssl)) {
sslv->rx_want = SSL_NOTHING;
}
sslv->tx_want = SSL_NOTHING;
if (ret > 0) {
ofpbuf_pull(sslv->txbuf, ret);
if (sslv->txbuf->size == 0) {
return 0;
}
} else {
int ssl_error = SSL_get_error(sslv->ssl, ret);
if (ssl_error == SSL_ERROR_ZERO_RETURN) {
VLOG_WARN_RL(&rl, "SSL_write: connection closed");
return EPIPE;
} else {
return interpret_ssl_error("SSL_write", ret, ssl_error,
&sslv->tx_want);
}
}
}
}
static ssize_t
ssl_send(struct stream *stream, const void *buffer, size_t n)
{
struct ssl_stream *sslv = ssl_stream_cast(stream);
if (sslv->txbuf) {
return -EAGAIN;
} else {
int error;
sslv->txbuf = ofpbuf_clone_data(buffer, n);
error = ssl_do_tx(stream);
switch (error) {
case 0:
ssl_clear_txbuf(sslv);
return n;
case EAGAIN:
leak_checker_claim(buffer);
return n;
default:
sslv->txbuf = NULL;
return -error;
}
}
}
static void
ssl_run(struct stream *stream)
{
struct ssl_stream *sslv = ssl_stream_cast(stream);
if (sslv->txbuf && ssl_do_tx(stream) != EAGAIN) {
ssl_clear_txbuf(sslv);
}
}
static void
ssl_run_wait(struct stream *stream)
{
struct ssl_stream *sslv = ssl_stream_cast(stream);
if (sslv->tx_want != SSL_NOTHING) {
poll_fd_wait(sslv->fd, want_to_poll_events(sslv->tx_want));
}
}
static void
ssl_wait(struct stream *stream, enum stream_wait_type wait)
{
struct ssl_stream *sslv = ssl_stream_cast(stream);
switch (wait) {
case STREAM_CONNECT:
if (stream_connect(stream) != EAGAIN) {
poll_immediate_wake();
} else {
switch (sslv->state) {
case STATE_TCP_CONNECTING:
poll_fd_wait(sslv->fd, POLLOUT);
break;
case STATE_SSL_CONNECTING:
/* ssl_connect() called SSL_accept() or SSL_connect(), which
* set up the status that we test here. */
poll_fd_wait(sslv->fd,
want_to_poll_events(SSL_want(sslv->ssl)));
break;
default:
NOT_REACHED();
}
}
break;
case STREAM_RECV:
if (sslv->rx_want != SSL_NOTHING) {
poll_fd_wait(sslv->fd, want_to_poll_events(sslv->rx_want));
} else {
poll_immediate_wake();
}
break;
case STREAM_SEND:
if (!sslv->txbuf) {
/* We have room in our tx queue. */
poll_immediate_wake();
} else {
/* stream_run_wait() will do the right thing; don't bother with
* redundancy. */
}
break;
default:
NOT_REACHED();
}
}
const struct stream_class ssl_stream_class = {
"ssl", /* name */
true, /* needs_probes */
ssl_open, /* open */
ssl_close, /* close */
ssl_connect, /* connect */
ssl_recv, /* recv */
ssl_send, /* send */
ssl_run, /* run */
ssl_run_wait, /* run_wait */
ssl_wait, /* wait */
};
/* Passive SSL. */
struct pssl_pstream
{
struct pstream pstream;
int fd;
};
const struct pstream_class pssl_pstream_class;
static struct pssl_pstream *
pssl_pstream_cast(struct pstream *pstream)
{
pstream_assert_class(pstream, &pssl_pstream_class);
return CONTAINER_OF(pstream, struct pssl_pstream, pstream);
}
static int
pssl_open(const char *name OVS_UNUSED, char *suffix, struct pstream **pstreamp,
uint8_t dscp)
{
struct pssl_pstream *pssl;
struct sockaddr_in sin;
char bound_name[128];
int retval;
int fd;
retval = ssl_init();
if (retval) {
return retval;
}
fd = inet_open_passive(SOCK_STREAM, suffix, OFP_SSL_PORT, &sin, dscp);
if (fd < 0) {
return -fd;
}
sprintf(bound_name, "pssl:%"PRIu16":"IP_FMT,
ntohs(sin.sin_port), IP_ARGS(&sin.sin_addr.s_addr));
pssl = xmalloc(sizeof *pssl);
pstream_init(&pssl->pstream, &pssl_pstream_class, bound_name);
pssl->fd = fd;
*pstreamp = &pssl->pstream;
return 0;
}
static void
pssl_close(struct pstream *pstream)
{
struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
close(pssl->fd);
free(pssl);
}
static int
pssl_accept(struct pstream *pstream, struct stream **new_streamp)
{
struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
struct sockaddr_in sin;
socklen_t sin_len = sizeof sin;
char name[128];
int new_fd;
int error;
new_fd = accept(pssl->fd, (struct sockaddr *) &sin, &sin_len);
if (new_fd < 0) {
error = errno;
if (error != EAGAIN) {
VLOG_DBG_RL(&rl, "accept: %s", strerror(error));
}
return error;
}
error = set_nonblocking(new_fd);
if (error) {
close(new_fd);
return error;
}
sprintf(name, "ssl:"IP_FMT, IP_ARGS(&sin.sin_addr));
if (sin.sin_port != htons(OFP_SSL_PORT)) {
sprintf(strchr(name, '\0'), ":%"PRIu16, ntohs(sin.sin_port));
}
return new_ssl_stream(name, new_fd, SERVER, STATE_SSL_CONNECTING, &sin,
new_streamp);
}
static void
pssl_wait(struct pstream *pstream)
{
struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
poll_fd_wait(pssl->fd, POLLIN);
}
const struct pstream_class pssl_pstream_class = {
"pssl",
true,
pssl_open,
pssl_close,
pssl_accept,
pssl_wait,
};
/*
* Returns true if OpenSSL error is WANT_READ or WANT_WRITE, indicating that
* OpenSSL is requesting that we call it back when the socket is ready for read
* or writing, respectively.
*/
static bool
ssl_wants_io(int ssl_error)
{
return (ssl_error == SSL_ERROR_WANT_WRITE
|| ssl_error == SSL_ERROR_WANT_READ);
}
static int
ssl_init(void)
{
static int init_status = -1;
if (init_status < 0) {
init_status = do_ssl_init();
assert(init_status >= 0);
}
return init_status;
}
static int
do_ssl_init(void)
{
SSL_METHOD *method;
SSL_library_init();
SSL_load_error_strings();
/* New OpenSSL changed TLSv1_method() to return a "const" pointer, so the
* cast is needed to avoid a warning with those newer versions. */
method = (SSL_METHOD *) TLSv1_method();
if (method == NULL) {
VLOG_ERR("TLSv1_method: %s", ERR_error_string(ERR_get_error(), NULL));
return ENOPROTOOPT;
}
ctx = SSL_CTX_new(method);
if (ctx == NULL) {
VLOG_ERR("SSL_CTX_new: %s", ERR_error_string(ERR_get_error(), NULL));
return ENOPROTOOPT;
}
SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
SSL_CTX_set_tmp_dh_callback(ctx, tmp_dh_callback);
SSL_CTX_set_mode(ctx, SSL_MODE_ENABLE_PARTIAL_WRITE);
SSL_CTX_set_mode(ctx, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
NULL);
return 0;
}
static DH *
tmp_dh_callback(SSL *ssl OVS_UNUSED, int is_export OVS_UNUSED, int keylength)
{
struct dh {
int keylength;
DH *dh;
DH *(*constructor)(void);
};
static struct dh dh_table[] = {
{1024, NULL, get_dh1024},
{2048, NULL, get_dh2048},
{4096, NULL, get_dh4096},
};
struct dh *dh;
for (dh = dh_table; dh < &dh_table[ARRAY_SIZE(dh_table)]; dh++) {
if (dh->keylength == keylength) {
if (!dh->dh) {
dh->dh = dh->constructor();
if (!dh->dh) {
out_of_memory();
}
}
return dh->dh;
}
}
VLOG_ERR_RL(&rl, "no Diffie-Hellman parameters for key length %d",
keylength);
return NULL;
}
/* Returns true if SSL is at least partially configured. */
bool
stream_ssl_is_configured(void)
{
return private_key.file_name || certificate.file_name || ca_cert.file_name;
}
static bool
update_ssl_config(struct ssl_config_file *config, const char *file_name)
{
struct timespec mtime;
int error;
if (ssl_init() || !file_name) {
return false;
}
/* If the file name hasn't changed and neither has the file contents, stop
* here. */
error = get_mtime(file_name, &mtime);
if (error && error != ENOENT) {
VLOG_ERR_RL(&rl, "%s: stat failed (%s)", file_name, strerror(error));
}
if (config->file_name
&& !strcmp(config->file_name, file_name)
&& mtime.tv_sec == config->mtime.tv_sec
&& mtime.tv_nsec == config->mtime.tv_nsec) {
return false;
}
/* Update 'config'. */
config->mtime = mtime;
if (file_name != config->file_name) {
free(config->file_name);
config->file_name = xstrdup(file_name);
}
return true;
}
static void
stream_ssl_set_private_key_file__(const char *file_name)
{
if (SSL_CTX_use_PrivateKey_file(ctx, file_name, SSL_FILETYPE_PEM) == 1) {
private_key.read = true;
} else {
VLOG_ERR("SSL_use_PrivateKey_file: %s",
ERR_error_string(ERR_get_error(), NULL));
}
}
void
stream_ssl_set_private_key_file(const char *file_name)
{
if (update_ssl_config(&private_key, file_name)) {
stream_ssl_set_private_key_file__(file_name);
}
}
static void
stream_ssl_set_certificate_file__(const char *file_name)
{
if (SSL_CTX_use_certificate_chain_file(ctx, file_name) == 1) {
certificate.read = true;
} else {
VLOG_ERR("SSL_use_certificate_file: %s",
ERR_error_string(ERR_get_error(), NULL));
}
}
void
stream_ssl_set_certificate_file(const char *file_name)
{
if (update_ssl_config(&certificate, file_name)) {
stream_ssl_set_certificate_file__(file_name);
}
}
/* Sets the private key and certificate files in one operation. Use this
* interface, instead of calling stream_ssl_set_private_key_file() and
* stream_ssl_set_certificate_file() individually, in the main loop of a
* long-running program whose key and certificate might change at runtime.
*
* This is important because of OpenSSL's behavior. If an OpenSSL context
* already has a certificate, and stream_ssl_set_private_key_file() is called
* to install a new private key, OpenSSL will report an error because the new
* private key does not match the old certificate. The other order, of setting
* a new certificate, then setting a new private key, does work.
*
* If this were the only problem, calling stream_ssl_set_certificate_file()
* before stream_ssl_set_private_key_file() would fix it. But, if the private
* key is changed before the certificate (e.g. someone "scp"s or "mv"s the new
* private key in place before the certificate), then OpenSSL would reject that
* change, and then the change of certificate would succeed, but there would be
* no associated private key (because it had only changed once and therefore
* there was no point in re-reading it).
*
* This function avoids both problems by, whenever either the certificate or
* the private key file changes, re-reading both of them, in the correct order.
*/
void
stream_ssl_set_key_and_cert(const char *private_key_file,
const char *certificate_file)
{
if (update_ssl_config(&private_key, private_key_file)
|| update_ssl_config(&certificate, certificate_file)) {
stream_ssl_set_certificate_file__(certificate_file);
stream_ssl_set_private_key_file__(private_key_file);
}
}
/* Reads the X509 certificate or certificates in file 'file_name'. On success,
* stores the address of the first element in an array of pointers to
* certificates in '*certs' and the number of certificates in the array in
* '*n_certs', and returns 0. On failure, stores a null pointer in '*certs', 0
* in '*n_certs', and returns a positive errno value.
*
* The caller is responsible for freeing '*certs'. */
static int
read_cert_file(const char *file_name, X509 ***certs, size_t *n_certs)
{
FILE *file;
size_t allocated_certs = 0;
*certs = NULL;
*n_certs = 0;
file = fopen(file_name, "r");
if (!file) {
VLOG_ERR("failed to open %s for reading: %s",
file_name, strerror(errno));
return errno;
}
for (;;) {
X509 *certificate;
int c;
/* Read certificate from file. */
certificate = PEM_read_X509(file, NULL, NULL, NULL);
if (!certificate) {
size_t i;
VLOG_ERR("PEM_read_X509 failed reading %s: %s",
file_name, ERR_error_string(ERR_get_error(), NULL));
for (i = 0; i < *n_certs; i++) {
X509_free((*certs)[i]);
}
free(*certs);
*certs = NULL;
*n_certs = 0;
return EIO;
}
/* Add certificate to array. */
if (*n_certs >= allocated_certs) {
*certs = x2nrealloc(*certs, &allocated_certs, sizeof **certs);
}
(*certs)[(*n_certs)++] = certificate;
/* Are there additional certificates in the file? */
do {
c = getc(file);
} while (isspace(c));
if (c == EOF) {
break;
}
ungetc(c, file);
}
fclose(file);
return 0;
}
/* Sets 'file_name' as the name of a file containing one or more X509
* certificates to send to the peer. Typical use in OpenFlow is to send the CA
* certificate to the peer, which enables a switch to pick up the controller's
* CA certificate on its first connection. */
void
stream_ssl_set_peer_ca_cert_file(const char *file_name)
{
X509 **certs;
size_t n_certs;
size_t i;
if (ssl_init()) {
return;
}
if (!read_cert_file(file_name, &certs, &n_certs)) {
for (i = 0; i < n_certs; i++) {
if (SSL_CTX_add_extra_chain_cert(ctx, certs[i]) != 1) {
VLOG_ERR("SSL_CTX_add_extra_chain_cert: %s",
ERR_error_string(ERR_get_error(), NULL));
}
}
free(certs);
}
}
/* Logs fingerprint of CA certificate 'cert' obtained from 'file_name'. */
static void
log_ca_cert(const char *file_name, X509 *cert)
{
unsigned char digest[EVP_MAX_MD_SIZE];
unsigned int n_bytes;
struct ds fp;
char *subject;
ds_init(&fp);
if (!X509_digest(cert, EVP_sha1(), digest, &n_bytes)) {
ds_put_cstr(&fp, "<out of memory>");
} else {
unsigned int i;
for (i = 0; i < n_bytes; i++) {
if (i) {
ds_put_char(&fp, ':');
}
ds_put_format(&fp, "%02hhx", digest[i]);
}
}
subject = X509_NAME_oneline(X509_get_subject_name(cert), NULL, 0);
VLOG_INFO("Trusting CA cert from %s (%s) (fingerprint %s)", file_name,
subject ? subject : "<out of memory>", ds_cstr(&fp));
OPENSSL_free(subject);
ds_destroy(&fp);
}
static void
stream_ssl_set_ca_cert_file__(const char *file_name,
bool bootstrap, bool force)
{
X509 **certs;
size_t n_certs;
struct stat s;
if (!update_ssl_config(&ca_cert, file_name) && !force) {
return;
}
if (!strcmp(file_name, "none")) {
verify_peer_cert = false;
VLOG_WARN("Peer certificate validation disabled "
"(this is a security risk)");
} else if (bootstrap && stat(file_name, &s) && errno == ENOENT) {
bootstrap_ca_cert = true;
} else if (!read_cert_file(file_name, &certs, &n_certs)) {
size_t i;
/* Set up list of CAs that the server will accept from the client. */
for (i = 0; i < n_certs; i++) {
/* SSL_CTX_add_client_CA makes a copy of the relevant data. */
if (SSL_CTX_add_client_CA(ctx, certs[i]) != 1) {
VLOG_ERR("failed to add client certificate %zu from %s: %s",
i, file_name,
ERR_error_string(ERR_get_error(), NULL));
} else {
log_ca_cert(file_name, certs[i]);
}
X509_free(certs[i]);
}
free(certs);
/* Set up CAs for OpenSSL to trust in verifying the peer's
* certificate. */
SSL_CTX_set_cert_store(ctx, X509_STORE_new());
if (SSL_CTX_load_verify_locations(ctx, file_name, NULL) != 1) {
VLOG_ERR("SSL_CTX_load_verify_locations: %s",
ERR_error_string(ERR_get_error(), NULL));
return;
}
bootstrap_ca_cert = false;
}
ca_cert.read = true;
}
/* Sets 'file_name' as the name of the file from which to read the CA
* certificate used to verify the peer within SSL connections. If 'bootstrap'
* is false, the file must exist. If 'bootstrap' is false, then the file is
* read if it is exists; if it does not, then it will be created from the CA
* certificate received from the peer on the first SSL connection. */
void
stream_ssl_set_ca_cert_file(const char *file_name, bool bootstrap)
{
stream_ssl_set_ca_cert_file__(file_name, bootstrap, false);
}
/* SSL protocol logging. */
static const char *
ssl_alert_level_to_string(uint8_t type)
{
switch (type) {
case 1: return "warning";
case 2: return "fatal";
default: return "<unknown>";
}
}
static const char *
ssl_alert_description_to_string(uint8_t type)
{
switch (type) {
case 0: return "close_notify";
case 10: return "unexpected_message";
case 20: return "bad_record_mac";
case 21: return "decryption_failed";
case 22: return "record_overflow";
case 30: return "decompression_failure";
case 40: return "handshake_failure";
case 42: return "bad_certificate";
case 43: return "unsupported_certificate";
case 44: return "certificate_revoked";
case 45: return "certificate_expired";
case 46: return "certificate_unknown";
case 47: return "illegal_parameter";
case 48: return "unknown_ca";
case 49: return "access_denied";
case 50: return "decode_error";
case 51: return "decrypt_error";
case 60: return "export_restriction";
case 70: return "protocol_version";
case 71: return "insufficient_security";
case 80: return "internal_error";
case 90: return "user_canceled";
case 100: return "no_renegotiation";
default: return "<unknown>";
}
}
static const char *
ssl_handshake_type_to_string(uint8_t type)
{
switch (type) {
case 0: return "hello_request";
case 1: return "client_hello";
case 2: return "server_hello";
case 11: return "certificate";
case 12: return "server_key_exchange";
case 13: return "certificate_request";
case 14: return "server_hello_done";
case 15: return "certificate_verify";
case 16: return "client_key_exchange";
case 20: return "finished";
default: return "<unknown>";
}
}
static void
ssl_protocol_cb(int write_p, int version OVS_UNUSED, int content_type,
const void *buf_, size_t len, SSL *ssl OVS_UNUSED, void *sslv_)
{
const struct ssl_stream *sslv = sslv_;
const uint8_t *buf = buf_;
struct ds details;
if (!VLOG_IS_DBG_ENABLED()) {
return;
}
ds_init(&details);
if (content_type == 20) {
ds_put_cstr(&details, "change_cipher_spec");
} else if (content_type == 21) {
ds_put_format(&details, "alert: %s, %s",
ssl_alert_level_to_string(buf[0]),
ssl_alert_description_to_string(buf[1]));
} else if (content_type == 22) {
ds_put_format(&details, "handshake: %s",
ssl_handshake_type_to_string(buf[0]));
} else {
ds_put_format(&details, "type %d", content_type);
}
VLOG_DBG("%s%u%s%s %s (%zu bytes)",
sslv->type == CLIENT ? "client" : "server",
sslv->session_nr, write_p ? "-->" : "<--",
stream_get_name(&sslv->stream), ds_cstr(&details), len);
ds_destroy(&details);
}
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