Merge unix socket direct-streamlocal@openssh.com

PR #199

Author: mkj

src/channel.h

@@ -102,7 +102,7 @@ struct ChanType {
 	void (*cleanup)(const struct Channel*);
 };
 
-/* Callback for connect_remote. errstring may be NULL if result == DROPBEAR_SUCCESS */
+/* Callback for connect_remote/connect_streamlocal. errstring may be NULL if result == DROPBEAR_SUCCESS */
 void channel_connect_done(int result, int sock, void* user_data, const char* errstring);
 
 void chaninitialise(const struct ChanType *chantypes[]);

src/default_options.h

@@ -73,6 +73,7 @@ IMPORTANT: Some options will require "make clean" after changes */
 
 #define DROPBEAR_SVR_LOCALTCPFWD 1
 #define DROPBEAR_SVR_REMOTETCPFWD 1
+#define DROPBEAR_SVR_LOCALSTREAMFWD 1
 
 /* Enable Authentication Agent Forwarding */
 #define DROPBEAR_SVR_AGENTFWD 1

src/netio.c

@@ -28,7 +28,12 @@ struct dropbear_progress_connection {
 Does not close sockets */
 static void remove_connect(struct dropbear_progress_connection *c, m_list_elem *iter) {
 	if (c->res) {
-		freeaddrinfo(c->res);
+		/* Only call freeaddrinfo if connection is not AF_UNIX. */
+		if (c->res->ai_family != AF_UNIX) {
+			freeaddrinfo(c->res);
+		} else {
+			m_free(c->res);
+		}
 	}
 	m_free(c->remotehost);
 	m_free(c->remoteport);
@@ -59,6 +64,7 @@ static void connect_try_next(struct dropbear_progress_connection *c) {
 	int err;
 	int res = 0;
 	int fastopen = 0;
+	int retry_errno = EINPROGRESS;
 #if DROPBEAR_CLIENT_TCP_FAST_OPEN
 	struct msghdr message;
 #endif
@@ -72,6 +78,11 @@ static void connect_try_next(struct dropbear_progress_connection *c) {
 			continue;
 		}
 
+		/* According to the connect(2) manpage it should be testing EAGAIN
+		 * rather than EINPROGRESS for unix sockets.
+		 */
+		retry_errno = r->ai_family == AF_UNIX ? EAGAIN : EINPROGRESS;
+
 		if (c->bind_address || c->bind_port) {
 			/* bind to a source port/address */
 			struct addrinfo hints;
@@ -116,7 +127,7 @@ static void connect_try_next(struct dropbear_progress_connection *c) {
 		setnonblocking(c->sock);
 
 #if DROPBEAR_CLIENT_TCP_FAST_OPEN
-		fastopen = (c->writequeue != NULL);
+		fastopen = (c->writequeue != NULL && r->ai_family != AF_UNIX);
 
 		if (fastopen) {
 			memset(&message, 0x0, sizeof(message));
@@ -153,7 +164,7 @@ static void connect_try_next(struct dropbear_progress_connection *c) {
 			res = connect(c->sock, r->ai_addr, r->ai_addrlen);
 		}
 
-		if (res < 0 && errno != EINPROGRESS) {
+		if (res < 0 && errno != retry_errno) {
 			/* failure */
 			m_free(c->errstring);
 			c->errstring = m_strdup(strerror(errno));
@@ -225,6 +236,58 @@ struct dropbear_progress_connection *connect_remote(const char* remotehost, cons
 	return c;
 }
 
+
+/* Connect to stream local socket. */
+struct dropbear_progress_connection *connect_streamlocal(const char* localpath,
+	connect_callback cb, void* cb_data, enum dropbear_prio prio)
+{
+	struct dropbear_progress_connection *c = NULL;
+	struct sockaddr_un *sunaddr;
+
+	c = m_malloc(sizeof(*c));
+	c->remotehost = m_strdup(localpath);
+	c->remoteport = NULL;
+	c->sock = -1;
+	c->cb = cb;
+	c->cb_data = cb_data;
+	c->prio = prio;
+
+	list_append(&ses.conn_pending, c);
+
+#if DROPBEAR_FUZZ
+	if (fuzz.fuzzing) {
+		c->errstring = m_strdup("fuzzing connect_streamlocal always fails");
+		return c;
+	}
+#endif
+
+	if (strlen(localpath) >= sizeof(sunaddr->sun_path)) {
+		c->errstring = m_strdup("Stream path too long");
+		TRACE(("localpath: %s is too long", localpath));
+		return c;
+	}
+
+	/*
+	 * Fake up a struct addrinfo for AF_UNIX connections.
+	 * remove_connect() must check ai_family
+	 * and use m_free() not freeaddirinfo() for AF_UNIX.
+	 */
+	c->res = m_malloc(sizeof(*c->res) + sizeof(*sunaddr));
+	c->res->ai_addr = (struct sockaddr *)(c->res + 1);
+	c->res->ai_addrlen = sizeof(*sunaddr);
+	c->res->ai_family = AF_UNIX;
+	c->res->ai_socktype = SOCK_STREAM;
+	c->res->ai_protocol = PF_UNSPEC;
+	sunaddr = (struct sockaddr_un *)c->res->ai_addr;
+	sunaddr->sun_family = AF_UNIX;
+	strlcpy(sunaddr->sun_path, localpath, sizeof(sunaddr->sun_path));
+
+	/* Copy to target iter */ 
+	c->res_iter = c->res;
+
+	return c;
+}
+
 void remove_connect_pending() {
 	while (ses.conn_pending.first) {
 		struct dropbear_progress_connection *c = ses.conn_pending.first->item;

src/netio.h

@@ -32,6 +32,11 @@ struct dropbear_progress_connection * connect_remote (const char* remotehost, co
 	connect_callback cb, void *cb_data, const char* bind_address, const char* bind_port,
 	enum dropbear_prio prio);
 
+/* Connect to local stream, always returns a progress connection, if it fails it will call the callback at a later point */
+struct dropbear_progress_connection * connect_streamlocal (const char* localpath,
+	connect_callback cb, void *cb_data,
+	enum dropbear_prio prio);
+
 /* Sets up for select() */
 void set_connect_fds(fd_set *writefd);
 /* Handles ready sockets after select() */

src/svr-session.c

@@ -75,6 +75,9 @@ static const struct ChanType *svr_chantypes[] = {
 	&svrchansess,
 #if DROPBEAR_SVR_LOCALTCPFWD
 	&svr_chan_tcpdirect,
+#endif
+#if DROPBEAR_SVR_LOCALSTREAMFWD
+	&svr_chan_streamlocal,
 #endif
 	NULL /* Null termination is mandatory. */
 };

src/svr-tcpfwd.c

@@ -56,6 +56,7 @@ void recv_msg_global_request_remotetcp() {
 static int svr_cancelremotetcp(void);
 static int svr_remotetcpreq(int *allocated_listen_port);
 static int newtcpdirect(struct Channel * channel);
+static int newstreamlocal(struct Channel * channel);
 
 #if DROPBEAR_SVR_REMOTETCPFWD
 static const struct ChanType svr_chan_tcpremote = {
@@ -309,3 +310,57 @@ static int newtcpdirect(struct Channel * channel) {
 }
 
 #endif /* DROPBEAR_SVR_LOCALTCPFWD */
+
+
+#if DROPBEAR_SVR_LOCALSTREAMFWD
+
+const struct ChanType svr_chan_streamlocal = {
+	"direct-streamlocal@openssh.com",
+	newstreamlocal, /* init */
+	NULL, /* checkclose */
+	NULL, /* reqhandler */
+	NULL, /* closehandler */
+	NULL /* cleanup */
+};
+
+/* Called upon creating a new stream local channel (ie we connect out to an
+ * address */
+static int newstreamlocal(struct Channel * channel) {
+
+	/*
+	https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL#rev1.30
+
+	byte		SSH_MSG_CHANNEL_OPEN
+	string		"direct-streamlocal@openssh.com"
+	uint32		sender channel
+	uint32		initial window size
+	uint32		maximum packet size
+	string		socket path
+	string		reserved
+	uint32		reserved
+	*/
+
+	char* destsocket = NULL;
+	unsigned int len;
+	int err = SSH_OPEN_ADMINISTRATIVELY_PROHIBITED;
+
+	TRACE(("streamlocal channel %d", channel->index))
+
+	destsocket = buf_getstring(ses.payload, &len);
+	if (len > MAX_HOST_LEN) {
+		TRACE(("leave streamlocal: destsocket too long"))
+		goto out;
+	}
+
+	channel->conn_pending = connect_streamlocal(destsocket, channel_connect_done,
+		channel, DROPBEAR_PRIO_NORMAL);
+
+	err = SSH_OPEN_IN_PROGRESS;
+
+out:
+	m_free(destsocket);
+	TRACE(("leave streamlocal: err %d", err))
+	return err;
+}
+
+#endif /* DROPBEAR_SVR_LOCALSTREAMFWD */

src/tcpfwd.h

@@ -63,6 +63,8 @@ void recv_msg_global_request_remotetcp(void);
 
 extern const struct ChanType svr_chan_tcpdirect;
 
+extern const struct ChanType svr_chan_streamlocal;
+
 /* Client */
 void setup_localtcp(void);
 void setup_remotetcp(void);