s_client/s_server: support unix domain sockets

The "-unix <path>" argument allows s_server and s_client to use a unix
domain socket in the filesystem instead of IPv4 ("-connect", "-port",
"-accept", etc). If s_server exits gracefully, such as when "-naccept"
is used and the requested number of SSL/TLS connections have occurred,
then the domain socket file is removed. On ctrl-C, it is likely that
the stale socket file will be left over, such that s_server would
normally fail to restart with the same arguments. For this reason,
s_server also supports an "-unlink" option, which will clean up any
stale socket file before starting.

If you have any reason to want encrypted IPC within an O/S instance,
this concept might come in handy. Otherwise it just demonstrates that
there is nothing about SSL/TLS that limits it to TCP/IP in any way.

(There might also be benchmarking and profiling use in this path, as
unix domain sockets are much lower overhead than connecting over local
IP addresses).
Signed-off-by: NGeoff Thorpe <geoff@openssl.org>

apps/s_apps.h

@@ -148,7 +148,14 @@ typedef fd_mask fd_set;
 #define PORT_STR        "4433"
 #define PROTOCOL        "tcp"
 
-int do_server(int port, int type, int *ret, int (*cb) (char *hostname, int s, int stype, unsigned char *context), unsigned char *context, int naccept);
+int do_server(int port, int type, int *ret,
+	      int (*cb)(char *hostname, int s, int stype, unsigned char *context),
+	      unsigned char *context, int naccept);
+#ifndef NO_SYS_UN_H
+int do_server_unix(const char *path, int *ret,
+		   int (*cb)(char *hostname, int s, int stype, unsigned char *context),
+		   unsigned char *context, int naccept);
+#endif
 #ifdef HEADER_X509_H
 int MS_CALLBACK verify_callback(int ok, X509_STORE_CTX *ctx);
 #endif
@@ -162,6 +169,9 @@ int ssl_print_curves(BIO *out, SSL *s, int noshared);
 #endif
 int ssl_print_tmp_key(BIO *out, SSL *s);
 int init_client(int *sock, const char *server, int port, int type);
+#ifndef NO_SYS_UN_H
+int init_client_unix(int *sock, const char *server);
+#endif
 int should_retry(int i);
 int extract_port(const char *str, short *port_ptr);
 int extract_host_port(char *str,char **host_ptr,unsigned char *ip,short *p);

apps/s_client.c

@@ -323,7 +323,8 @@ static void sc_usage(void)
 	BIO_printf(bio_err,"\n");
 	BIO_printf(bio_err," -host host     - use -connect instead\n");
 	BIO_printf(bio_err," -port port     - use -connect instead\n");
-	BIO_printf(bio_err," -connect host:port - who to connect to (default is %s:%s)\n",SSL_HOST_NAME,PORT_STR);
+	BIO_printf(bio_err," -connect host:port - connect over TCP/IP (default is %s:%s)\n",SSL_HOST_NAME,PORT_STR);
+	BIO_printf(bio_err," -unix path    - connect over unix domain sockets\n");
 	BIO_printf(bio_err," -verify arg   - turn on peer certificate verification\n");
 	BIO_printf(bio_err," -cert arg     - certificate file to use, PEM format assumed\n");
 	BIO_printf(bio_err," -certform arg - certificate format (PEM or DER) PEM default\n");
@@ -627,6 +628,7 @@ int MAIN(int argc, char **argv)
 	short port=PORT;
 	int full_log=1;
 	char *host=SSL_HOST_NAME;
+	const char *unix_path = NULL;
 	char *xmpphost = NULL;
 	char *cert_file=NULL,*key_file=NULL,*chain_file=NULL;
 	int cert_format = FORMAT_PEM, key_format = FORMAT_PEM;
@@ -760,6 +762,11 @@ static char *jpake_secret = NULL;
 			if (!extract_host_port(*(++argv),&host,NULL,&port))
 				goto bad;
 			}
+		else if (strcmp(*argv,"-unix") == 0)
+			{
+			if (--argc < 1) goto bad;
+			unix_path = *(++argv);
+			}
 		else if	(strcmp(*argv,"-xmpphost") == 0)
 			{
 			if (--argc < 1) goto bad;
@@ -1155,6 +1162,11 @@ bad:
 		goto end;
 		}
 
+	if (unix_path && (socket_type != SOCK_STREAM))
+		{
+		BIO_printf(bio_err, "Can't use unix sockets and datagrams together\n");
+			goto end;
+		}
 #if !defined(OPENSSL_NO_JPAKE) && !defined(OPENSSL_NO_PSK)
 	if (jpake_secret)
 		{
@@ -1499,7 +1511,8 @@ bad:
 
 re_start:
 
-	if (init_client(&s,host,port,socket_type) == 0)
+	if ((!unix_path && (init_client(&s,host,port,socket_type) == 0)) ||
+			(unix_path && (init_client_unix(&s,unix_path) == 0)))
 		{
 		BIO_printf(bio_err,"connect:errno=%d\n",get_last_socket_error());
 		SHUTDOWN(s);

apps/s_server.c

@@ -479,7 +479,9 @@ static void sv_usage(void)
 	{
 	BIO_printf(bio_err,"usage: s_server [args ...]\n");
 	BIO_printf(bio_err,"\n");
-	BIO_printf(bio_err," -accept arg   - port to accept on (default is %d)\n",PORT);
+	BIO_printf(bio_err," -accept port  - TCP/IP port to accept on (default is %d)\n",PORT);
+	BIO_printf(bio_err," -unix path    - unix domain socket to accept on\n");
+	BIO_printf(bio_err," -unlink       - for -unix, unlink existing socket first\n");
 	BIO_printf(bio_err," -context arg  - set session ID context\n");
 	BIO_printf(bio_err," -verify arg   - turn on peer certificate verification\n");
 	BIO_printf(bio_err," -Verify arg   - turn on peer certificate verification, must have a cert.\n");
@@ -1008,6 +1010,9 @@ int MAIN(int argc, char *argv[])
 	X509_VERIFY_PARAM *vpm = NULL;
 	int badarg = 0;
 	short port=PORT;
+	const char *unix_path=NULL;
+	int unlink_unix_path=0;
+	int (*server_cb)(char *hostname, int s, int stype, unsigned char *context);
 	char *CApath=NULL,*CAfile=NULL;
 	char *chCApath=NULL,*chCAfile=NULL;
 	char *vfyCApath=NULL,*vfyCAfile=NULL;
@@ -1100,6 +1105,25 @@ int MAIN(int argc, char *argv[])
 			if (!extract_port(*(++argv),&port))
 				goto bad;
 			}
+		else if (strcmp(*argv,"-unix") == 0)
+			{
+#ifdef NO_SYS_UN_H
+			BIO_printf(bio_err, "unix domain sockets unsupported\n");
+			goto bad;
+#else
+			if (--argc < 1) goto bad;
+			unix_path = *(++argv);
+#endif
+			}
+		else if (strcmp(*argv,"-unlink") == 0)
+			{
+#ifdef NO_SYS_UN_H
+			BIO_printf(bio_err, "unix domain sockets unsupported\n");
+			goto bad;
+#else
+			unlink_unix_path = 1;
+#endif
+			}
 		else if	(strcmp(*argv,"-naccept") == 0)
 			{
 			if (--argc < 1) goto bad;
@@ -1544,6 +1568,11 @@ bad:
 		goto end;
 		}
 
+	if (unix_path && (socket_type != SOCK_STREAM))
+		{
+		BIO_printf(bio_err, "Can't use unix sockets and datagrams together\n");
+			goto end;
+		}
 #if !defined(OPENSSL_NO_JPAKE) && !defined(OPENSSL_NO_PSK)
 	if (jpake_secret)
 		{
@@ -2106,11 +2135,19 @@ bad:
 	BIO_printf(bio_s_out,"ACCEPT\n");
 	(void)BIO_flush(bio_s_out);
 	if (rev)
-		do_server(port,socket_type,&accept_socket,rev_body, context, naccept);
+		server_cb = rev_body;
 	else if (www)
-		do_server(port,socket_type,&accept_socket,www_body, context, naccept);
+		server_cb = www_body;
+	else
+		server_cb = sv_body;
+	if (unix_path)
+		{
+		if (unlink_unix_path)
+			unlink(unix_path);
+		do_server_unix(unix_path,&accept_socket,server_cb, context, naccept);
+		}
 	else
-		do_server(port,socket_type,&accept_socket,sv_body, context, naccept);
+		do_server(port,socket_type,&accept_socket,server_cb, context, naccept);
 	print_stats(bio_s_out,ctx);
 	ret=0;
 end:

apps/s_socket.c

@@ -102,6 +102,10 @@ static int init_server(int *sock, int port, int type);
 static int init_server_long(int *sock, int port,char *ip, int type);
 static int do_accept(int acc_sock, int *sock, char **host);
 static int host_ip(const char *str, unsigned char ip[4]);
+#ifndef NO_SYS_UN_H
+static int init_server_unix(int *sock, const char *path);
+static int do_accept_unix(int acc_sock, int *sock);
+#endif
 
 #ifdef OPENSSL_SYS_WIN16
 #define SOCKET_PROTOCOL	0 /* more microsoft stupidity */
@@ -280,7 +284,32 @@ static int init_client_ip(int *sock, const unsigned char ip[4], int port,
 	return(1);
 	}
 
-int do_server(int port, int type, int *ret, int (*cb)(char *hostname, int s, int stype, unsigned char *context), unsigned char *context, int naccept)
+#ifndef NO_SYS_UN_H
+int init_client_unix(int *sock, const char *server)
+	{
+	struct sockaddr_un them;
+	int s;
+
+	if (strlen(server) > (UNIX_PATH_MAX + 1)) return(0);
+	if (!ssl_sock_init()) return(0);
+
+	s=socket(AF_UNIX, SOCK_STREAM, 0);
+	if (s == INVALID_SOCKET) { perror("socket"); return(0); }
+
+	memset((char *)&them,0,sizeof(them));
+	them.sun_family=AF_UNIX;
+	strcpy(them.sun_path, server);
+
+	if (connect(s, (struct sockaddr *)&them, sizeof(them)) == -1)
+		{ closesocket(s); perror("connect"); return(0); }
+	*sock=s;
+	return(1);
+	}
+#endif
+
+int do_server(int port, int type, int *ret,
+	      int (*cb)(char *hostname, int s, int stype, unsigned char *context),
+	      unsigned char *context, int naccept)
 	{
 	int sock;
 	char *name = NULL;
@@ -324,6 +353,43 @@ int do_server(int port, int type, int *ret, int (*cb)(char *hostname, int s, int
 		}
 	}
 
+#ifndef NO_SYS_UN_H
+int do_server_unix(const char *path, int *ret,
+		   int (*cb)(char *hostname, int s, int stype, unsigned char *context),
+		   unsigned char *context, int naccept)
+	{
+	int sock;
+	int accept_socket = 0;
+	int i;
+
+	if (!init_server_unix(&accept_socket, path)) return(0);
+
+	if (ret != NULL)
+		*ret=accept_socket;
+	for (;;)
+		{
+		if (do_accept_unix(accept_socket, &sock) == 0)
+			{
+			SHUTDOWN(accept_socket);
+			i = 0;
+			goto out;
+			}
+		i=(*cb)(NULL, sock, 0, context);
+		SHUTDOWN2(sock);
+		if (naccept != -1)
+			naccept--;
+		if (i < 0 || naccept == 0)
+			{
+			SHUTDOWN2(accept_socket);
+			goto out;
+			}
+		}
+out:
+	unlink(path);
+	return(i);
+	}
+#endif
+
 static int init_server_long(int *sock, int port, char *ip, int type)
 	{
 	int ret=0;
@@ -382,6 +448,50 @@ static int init_server(int *sock, int port, int type)
 	return(init_server_long(sock, port, NULL, type));
 	}
 
+#ifndef NO_SYS_UN_H
+static int init_server_unix(int *sock, const char *path)
+	{
+	int ret = 0;
+	struct sockaddr_un server;
+	int s = -1;
+
+	if (strlen(path) > (UNIX_PATH_MAX + 1)) return(0);
+	if (!ssl_sock_init()) return(0);
+
+	s=socket(AF_UNIX, SOCK_STREAM, 0);
+	if (s == INVALID_SOCKET) goto err;
+
+	memset((char *)&server,0,sizeof(server));
+	server.sun_family=AF_UNIX;
+	strcpy(server.sun_path, path);
+
+	if (bind(s, (struct sockaddr *)&server, sizeof(server)) == -1)
+		{
+#ifndef OPENSSL_SYS_WINDOWS
+		perror("bind");
+#endif
+		goto err;
+		}
+	/* Make it 128 for linux */
+	if (listen(s,128) == -1)
+		{
+#ifndef OPENSSL_SYS_WINDOWS
+		perror("listen");
+#endif
+		unlink(path);
+		goto err;
+		}
+	*sock=s;
+	ret=1;
+err:
+	if ((ret == 0) && (s != -1))
+		{
+		SHUTDOWN(s);
+		}
+	return(ret);
+	}
+#endif
+
 static int do_accept(int acc_sock, int *sock, char **host)
 	{
 	int ret;
@@ -476,6 +586,32 @@ end:
 	return(1);
 	}
 
+#ifndef NO_SYS_UN_H
+static int do_accept_unix(int acc_sock, int *sock)
+	{
+	int ret;
+
+	if (!ssl_sock_init()) return(0);
+
+redoit:
+	ret=accept(acc_sock, NULL, NULL);
+	if (ret == INVALID_SOCKET)
+		{
+		if (errno == EINTR)
+			{
+			/*check_timeout(); */
+			goto redoit;
+			}
+		fprintf(stderr,"errno=%d ",errno);
+		perror("accept");
+		return(0);
+		}
+
+	*sock=ret;
+	return(1);
+	}
+#endif
+
 int extract_host_port(char *str, char **host_ptr, unsigned char *ip,
 	     short *port_ptr)
 	{

e_os.h

@@ -579,6 +579,16 @@ static unsigned int _strlen31(const char *str)
 #      include <inet.h>
 #    else
 #      include <sys/socket.h>
+#      ifndef NO_SYS_UN_H
+#        ifdef OPENSSL_SYS_VXWORKS
+#          include <streams/un.h>
+#        else
+#          include <sys/un.h>
+#        endif
+#        ifndef UNIX_PATH_MAX
+#          define UNIX_PATH_MAX sizeof(((struct sockaddr_un *)NULL)->sun_path)
+#        endif
+#      endif
 #      ifdef FILIO_H
 #        include <sys/filio.h> /* Added for FIONBIO under unixware */
 #      endif