freebsd-skq/usr.sbin/rpc.yppasswdd/yppasswd_comm.c
1997-02-22 16:15:28 +00:00

304 lines
8.0 KiB
C

/*
* Copyright (c) 1995, 1996
* Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Bill Paul.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL Bill Paul OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id$
*/
/*
* This file contains a UNIX domain socket communications package
* that lets a client process send pseudo-RPCs to rpc.yppasswdd
* without using IP. This 'local-only' communications channel is
* only used when the superuser runs passwd(1) or chpass(1) on
* the NIS master server. The idea is that we want to grant the
* superuser permission to perfom certain special operations, but
* we need an iron-clad way to tell when we're receiving a request
* from the superuser and when we aren't. To connect to a UNIX
* domain socket, one needs to be able to access a file in the
* filesystem. The socket created by rpc.yppasswdd is owned by
* root and has all its permission bits cleared, so the only
* user who can sucessfully connect() to it is root.
*
* It is the server's responsibility to initialize the listening
* socket with the makeservsock() function and to add the socket to
* the set of file descriptors monitored by the svc_run() loop.
* Once this is done, calls made through the UNIX domain socket
* can be handled almost exactly like a normal RPC. We even use
* the XDR functions for serializing data between the client and
* server to simplify the passing of complex data structures.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <err.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/fcntl.h>
#include <rpc/rpc.h>
#include <rpcsvc/yp.h>
#include "yppasswd_comm.h"
#include "yppasswd_private.h"
#include "ypxfr_extern.h"
#ifndef lint
static const char rcsid[] = "$Id$";
#endif
char *sockname = "/var/run/ypsock";
FILE *serv_fp;
FILE *clnt_fp;
int serv_sock;
int clnt_sock;
/*
* serialize_data() and serialize_resp() are what really do most of
* the work. These functions (ab)use xdrstdio_create() as the interface
* to the XDR library. The RPC library uses xdrrec_create() and friends
* for TCP based connections. I suppose we could use that here, but
* the interface is a bit too complicated to justify using in an
* applicatuion such as this. With xdrstdio_create(), the only catch
* is that we need to provide a buffered file stream rather than
* a simple socket descriptor, but we can easily turn the latter into
* the former using fdopen(2).
*
* Doing things this way buys us the ability to change the form of
* the data being exchanged without having to modify any of the
* routines in this package.
*/
static int serialize_data(data, fp, op)
struct master_yppasswd *data;
FILE *fp;
int op;
{
XDR xdrs;
xdrstdio_create(&xdrs, fp, op);
if (!xdr_master_yppasswd(&xdrs, data)) {
xdr_destroy(&xdrs);
return(1);
}
return(0);
}
static int serialize_resp(resp, fp, op)
int *resp;
FILE *fp;
int op;
{
XDR xdrs;
xdrstdio_create(&xdrs, fp, op);
if (!xdr_int(&xdrs, resp)) {
xdr_destroy(&xdrs);
return(1);
}
return(0);
}
/*
* Build the server's listening socket. The descriptor generated
* here will be monitored for new connections by the svc_run() loop.
*/
int makeservsock()
{
static int ypsock;
struct sockaddr_un us;
int len;
unlink(sockname);
if ((ypsock = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
err(1, "failed to create UNIX domain socket");
bzero((char *)&us, sizeof(us));
us.sun_family = AF_UNIX;
strcpy((char *)&us.sun_path, sockname);
us.sun_len = len = sizeof(us.sun_len) + sizeof(us.sun_family) +
strlen(us.sun_path) + 1;
if (bind(ypsock, (struct sockaddr *)&us, len) == -1)
err(1,"failed to bind UNIX domain socket");
listen (ypsock, 1);
return(ypsock);
}
/*
* Create a socket for a client and try to connect() it to the
* server.
*/
static int makeclntsock()
{
static int ypsock;
struct sockaddr_un us;
int len;
if ((ypsock = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
warn("failed to create UNIX domain socket");
return(-1);
}
bzero((char *)&us, sizeof(us));
us.sun_family = AF_UNIX;
strcpy((char *)&us.sun_path, sockname);
us.sun_len = len = sizeof(us.sun_len) + sizeof(us.sun_family) +
strlen(us.sun_path) + 1;
if (connect(ypsock, (struct sockaddr *)&us, len) == -1) {
warn("failed to connect to server");
return(-1);
}
return(ypsock);
}
/*
* This function is used by the server to accept a new connection
* from a client and read its request data into a master_yppasswd
* stucture.
*/
struct master_yppasswd *getdat(sock)
int sock;
{
int len;
struct sockaddr_un us;
static struct master_yppasswd pw;
struct timeval tv;
fd_set fds;
FD_ZERO(&fds);
FD_SET(sock, &fds);
tv.tv_sec = CONNECTION_TIMEOUT;
tv.tv_usec = 0;
switch(select(FD_SETSIZE, &fds, NULL, NULL, &tv)) {
case 0:
yp_error("select timed out");
return(NULL);
break;
case -1:
yp_error("select() failed: %s", strerror(errno));
return(NULL);
break;
default:
break;
}
len = sizeof(us);
if ((serv_sock = accept(sock, (struct sockaddr *)&us, &len)) == -1) {
yp_error("accept failed: %s", strerror(errno));
return(NULL);
}
if ((serv_fp = fdopen(serv_sock, "r+")) == NULL) {
yp_error("fdopen failed: %s",strerror(errno));
return(NULL);
}
if (serialize_data(&pw, serv_fp, XDR_DECODE)) {
yp_error("failed to receive data");
return(NULL);
}
return(&pw);
}
/*
* Client uses this to read back a response code (a single
* integer) from the server. Note that we don't need to implement
* any special XDR function for this since an int is a base data
* type which the XDR library can handle directly.
*/
int *getresp()
{
static int resp;
if (serialize_resp(&resp, clnt_fp, XDR_DECODE)) {
warn("failed to receive response");
return(NULL);
}
fclose(clnt_fp);
close(clnt_sock);
return(&resp);
}
/*
* Create a connection to the server and send a reqest
* to be processed.
*/
int senddat(pw)
struct master_yppasswd *pw;
{
if ((clnt_sock = makeclntsock()) == -1) {
warn("failed to create socket");
return(1);
}
if ((clnt_fp = fdopen(clnt_sock, "r+")) == NULL) {
warn("fdopen failed");
return(1);
}
if (serialize_data(pw, clnt_fp, XDR_ENCODE)) {
warn("failed to send data");
return(1);
}
return(0);
}
/*
* This sends a response code back to the client.
*/
int sendresp(resp)
int resp;
{
if (serialize_resp(&resp, serv_fp, XDR_ENCODE)) {
yp_error("failed to send response");
return(-1);
}
fclose(serv_fp);
close(serv_sock);
return(0);
}