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-rw-r--r--src/tls/tls_proxy_clnt.c292
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diff --git a/src/tls/tls_proxy_clnt.c b/src/tls/tls_proxy_clnt.c
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+/*++
+/* NAME
+/* tlsproxy_clnt 3
+/* SUMMARY
+/* tlsproxy(8) client support
+/* SYNOPSIS
+/* #include <tlsproxy_clnt.h>
+/*
+/* VSTREAM *tls_proxy_open(service, flags, peer_stream, peer_addr,
+/* peer_port, handshake_timeout, session_timeout,
+/* serverid, tls_params, init_props, start_props)
+/* const char *service;
+/* int flags;
+/* VSTREAM *peer_stream;
+/* const char *peer_addr;
+/* const char *peer_port;
+/* int handshake_timeout;
+/* int session_timeout;
+/* const char *serverid;
+/* void *tls_params;
+/* void *init_props;
+/* void *start_props;
+/*
+/* TLS_SESS_STATE *tls_proxy_context_receive(proxy_stream)
+/* VSTREAM *proxy_stream;
+/* AUXILIARY FUNCTIONS
+/* VSTREAM *tls_proxy_legacy_open(service, flags, peer_stream,
+/* peer_addr, peer_port,
+/* timeout, serverid)
+/* const char *service;
+/* int flags;
+/* VSTREAM *peer_stream;
+/* const char *peer_addr;
+/* const char *peer_port;
+/* int timeout;
+/* const char *serverid;
+/* DESCRIPTION
+/* tls_proxy_open() prepares for inserting the tlsproxy(8)
+/* daemon between the current process and a remote peer (the
+/* actual insert operation is described in the next paragraph).
+/* The result value is a null pointer on failure. The peer_stream
+/* is not closed. The resulting proxy stream is single-buffered.
+/*
+/* After this, it is a good idea to use the CA_VSTREAM_CTL_SWAP_FD
+/* request to swap the file descriptors between the plaintext
+/* peer_stream and the proxy stream from tls_proxy_open().
+/* This avoids the loss of application-configurable VSTREAM
+/* attributes on the plaintext peer_stream (such as longjmp
+/* buffer, timeout, etc.). Once the file descriptors are
+/* swapped, the proxy stream should be closed.
+/*
+/* tls_proxy_context_receive() receives the TLS context object
+/* for the named proxy stream. This function must be called
+/* only if the TLS_PROXY_SEND_CONTEXT flag was specified in
+/* the tls_proxy_open() call. Note that this TLS context object
+/* is not compatible with tls_session_free(). It must be given
+/* to tls_proxy_context_free() instead.
+/*
+/* After this, the proxy_stream is ready for plain-text I/O.
+/*
+/* tls_proxy_legacy_open() is a backwards-compatibility feature
+/* that provides a historical interface.
+/*
+/* Arguments:
+/* .IP service
+/* The (base) name of the tlsproxy service.
+/* .IP flags
+/* Bit-wise OR of:
+/* .RS
+/* .IP TLS_PROXY_FLAG_ROLE_SERVER
+/* Request the TLS server proxy role.
+/* .IP TLS_PROXY_FLAG_ROLE_CLIENT
+/* Request the TLS client proxy role.
+/* .IP TLS_PROXY_FLAG_SEND_CONTEXT
+/* Send the TLS context object.
+/* .RE
+/* .IP peer_stream
+/* Stream that connects the current process to a remote peer.
+/* .IP peer_addr
+/* Printable IP address of the remote peer_stream endpoint.
+/* .IP peer_port
+/* Printable TCP port of the remote peer_stream endpoint.
+/* .IP handshake_timeout
+/* Time limit that the tlsproxy(8) daemon should use during
+/* the TLS handshake.
+/* .IP session_timeout
+/* Time limit that the tlsproxy(8) daemon should use after the
+/* TLS handshake.
+/* .IP serverid
+/* Unique service identifier.
+/* .IP tls_params
+/* Pointer to TLS_CLIENT_PARAMS or TLS_SERVER_PARAMS.
+/* .IP init_props
+/* Pointer to TLS_CLIENT_INIT_PROPS or TLS_SERVER_INIT_PROPS.
+/* .IP start_props
+/* Pointer to TLS_CLIENT_START_PROPS or TLS_SERVER_START_PROPS.
+/* .IP proxy_stream
+/* Stream from tls_proxy_open().
+/* .IP tls_context
+/* TLS session object from tls_proxy_context_receive().
+/* LICENSE
+/* .ad
+/* .fi
+/* The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/* Wietse Venema
+/* IBM T.J. Watson Research
+/* P.O. Box 704
+/* Yorktown Heights, NY 10598, USA
+/*
+/* Wietse Venema
+/* Google, Inc.
+/* 111 8th Avenue
+/* New York, NY 10011, USA
+/*--*/
+
+#ifdef USE_TLS
+
+/* System library. */
+
+#include <sys_defs.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <connect.h>
+#include <stringops.h>
+#include <vstring.h>
+
+/* Global library. */
+
+#include <mail_proto.h>
+#include <mail_params.h>
+
+/* TLS library-specific. */
+
+#include <tls.h>
+#include <tls_proxy.h>
+
+#define TLSPROXY_INIT_TIMEOUT 10
+
+/* SLMs. */
+
+#define STR vstring_str
+
+/* tls_proxy_open - open negotiations with TLS proxy */
+
+VSTREAM *tls_proxy_open(const char *service, int flags,
+ VSTREAM *peer_stream,
+ const char *peer_addr,
+ const char *peer_port,
+ int handshake_timeout,
+ int session_timeout,
+ const char *serverid,
+ void *tls_params,
+ void *init_props,
+ void *start_props)
+{
+ const char myname[] = "tls_proxy_open";
+ VSTREAM *tlsproxy_stream;
+ int status;
+ int fd;
+ static VSTRING *tlsproxy_service = 0;
+ static VSTRING *remote_endpt = 0;
+
+ /*
+ * Initialize.
+ */
+ if (tlsproxy_service == 0) {
+ tlsproxy_service = vstring_alloc(20);
+ remote_endpt = vstring_alloc(20);
+ }
+
+ /*
+ * Connect to the tlsproxy(8) daemon.
+ */
+ vstring_sprintf(tlsproxy_service, "%s/%s", MAIL_CLASS_PRIVATE, service);
+ if ((fd = LOCAL_CONNECT(STR(tlsproxy_service), BLOCKING,
+ TLSPROXY_INIT_TIMEOUT)) < 0) {
+ msg_warn("connect to %s service: %m", STR(tlsproxy_service));
+ return (0);
+ }
+
+ /*
+ * Initial handshake. Send common data attributes now, and send the
+ * remote peer file descriptor in a later transaction.
+ */
+ tlsproxy_stream = vstream_fdopen(fd, O_RDWR);
+ vstring_sprintf(remote_endpt, "[%s]:%s", peer_addr, peer_port);
+ attr_print(tlsproxy_stream, ATTR_FLAG_NONE,
+ SEND_ATTR_STR(TLS_ATTR_REMOTE_ENDPT, STR(remote_endpt)),
+ SEND_ATTR_INT(TLS_ATTR_FLAGS, flags),
+ SEND_ATTR_INT(TLS_ATTR_TIMEOUT, handshake_timeout),
+ SEND_ATTR_INT(TLS_ATTR_TIMEOUT, session_timeout),
+ SEND_ATTR_STR(TLS_ATTR_SERVERID, serverid),
+ ATTR_TYPE_END);
+ /* Do not flush the stream yet. */
+ if (vstream_ferror(tlsproxy_stream) != 0) {
+ msg_warn("error sending request to %s service: %m",
+ STR(tlsproxy_service));
+ vstream_fclose(tlsproxy_stream);
+ return (0);
+ }
+ switch (flags & (TLS_PROXY_FLAG_ROLE_CLIENT | TLS_PROXY_FLAG_ROLE_SERVER)) {
+ case TLS_PROXY_FLAG_ROLE_CLIENT:
+ attr_print(tlsproxy_stream, ATTR_FLAG_NONE,
+ SEND_ATTR_FUNC(tls_proxy_client_param_print, tls_params),
+ SEND_ATTR_FUNC(tls_proxy_client_init_print, init_props),
+ SEND_ATTR_FUNC(tls_proxy_client_start_print, start_props),
+ ATTR_TYPE_END);
+ break;
+ case TLS_PROXY_FLAG_ROLE_SERVER:
+#if 0
+ attr_print(tlsproxy_stream, ATTR_FLAG_NONE,
+ SEND_ATTR_FUNC(tls_proxy_server_param_print, tls_params),
+ SEND_ATTR_FUNC(tls_proxy_server_init_print, init_props),
+ SEND_ATTR_FUNC(tls_proxy_server_start_print, start_props),
+ ATTR_TYPE_END);
+#endif
+ break;
+ default:
+ msg_panic("%s: bad flags: 0x%x", myname, flags);
+ }
+ if (vstream_fflush(tlsproxy_stream) != 0) {
+ msg_warn("error sending request to %s service: %m",
+ STR(tlsproxy_service));
+ vstream_fclose(tlsproxy_stream);
+ return (0);
+ }
+
+ /*
+ * Receive the "TLS is available" indication.
+ *
+ * This may seem out of order, but we must have a read transaction between
+ * sending the request attributes and sending the plaintext file
+ * descriptor. We can't assume UNIX-domain socket semantics here.
+ */
+ if (attr_scan(tlsproxy_stream, ATTR_FLAG_STRICT,
+ RECV_ATTR_INT(MAIL_ATTR_STATUS, &status),
+ /* TODO: informative message. */
+ ATTR_TYPE_END) != 1 || status == 0) {
+
+ /*
+ * The TLS proxy reports that the TLS engine is not available (due to
+ * configuration error, or other causes).
+ */
+ msg_warn("%s service role \"%s\" is not available",
+ STR(tlsproxy_service),
+ (flags & TLS_PROXY_FLAG_ROLE_SERVER) ? "server" :
+ (flags & TLS_PROXY_FLAG_ROLE_CLIENT) ? "client" :
+ "bogus role");
+ vstream_fclose(tlsproxy_stream);
+ return (0);
+ }
+
+ /*
+ * Send the remote peer file descriptor.
+ */
+ if (LOCAL_SEND_FD(vstream_fileno(tlsproxy_stream),
+ vstream_fileno(peer_stream)) < 0) {
+
+ /*
+ * Some error: drop the TLS proxy stream.
+ */
+ msg_warn("sending file handle to %s service: %m",
+ STR(tlsproxy_service));
+ vstream_fclose(tlsproxy_stream);
+ return (0);
+ }
+ return (tlsproxy_stream);
+}
+
+
+/* tls_proxy_context_receive - receive TLS session object from tlsproxy(8) */
+
+TLS_SESS_STATE *tls_proxy_context_receive(VSTREAM *proxy_stream)
+{
+ TLS_SESS_STATE *tls_context = 0;
+
+ if (attr_scan(proxy_stream, ATTR_FLAG_STRICT,
+ RECV_ATTR_FUNC(tls_proxy_context_scan, (void *) &tls_context),
+ ATTR_TYPE_END) != 1) {
+ if (tls_context)
+ tls_proxy_context_free(tls_context);
+ return (0);
+ } else {
+ return (tls_context);
+ }
+}
+
+#endif
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