/***********************************************************
Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts,
and the Massachusetts Institute of Technology, Cambridge, Massachusetts.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its 
documentation for any purpose and without fee is hereby granted, 
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in 
supporting documentation, and that the names of Digital or MIT not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.  

DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.

******************************************************************/

/* $XConsortium: access.c,v 1.40 89/10/03 16:43:48 keith Exp $ */

#include "Xos.h"
#include "X.h"
#include "Xproto.h"
#include "misc.h"
#include "site.h"
#include <errno.h>
#include <sys/socket.h>
#include <sys/ioctl.h>

#ifdef hpux
# include <sys/utsname.h>
# ifdef HAS_IFREQ
#  include <net/if.h>
# endif
#else
# include <net/if.h>
#endif /* hpux */

#include <netdb.h>
#ifdef TCPCONN
#include <netinet/in.h>
#endif /* TCPCONN */
#ifdef DNETCONN
#include <netdnet/dn.h>
#include <netdnet/dnetdb.h>
#endif
#undef NULL
#include <stdio.h>
#include "dixstruct.h"
#include "osdep.h"

#define acmp(a1, a2, len) bcmp((char *)(a1), (char *)(a2), len)
#define acopy(a1, a2, len) bcopy((char *)(a1), (char *)(a2), len)
#define addrEqual(fam, address, length, host) \
			 ((fam) == (host)->family &&\
			  (length) == (host)->len &&\
			  !acmp (address, (host)->addr, length))

#ifdef hpux
#define getpeername(fd, from, fromlen)	hpux_getpeername(fd, from, fromlen)
#endif

#define DONT_CHECK -1
extern char	*index();

static int XFamily(), UnixFamily();
static int ConvertAddr(), CheckFamily();
static void NewHost();

typedef struct _host {
	short		family;
	short		len;
	unsigned char	addr[4];	/* will need to be bigger eventually */
	struct _host *next;
} HOST;

static HOST *selfhosts = NULL;
static HOST *validhosts = NULL;
static int AccessEnabled = DEFAULT_ACCESS_CONTROL;
static int LocalHostEnabled = TRUE;
static int UsingXdmcp = FALSE;

typedef struct {
    int af, xf;
} FamilyMap;

static FamilyMap familyMap[] = {
#ifdef     AF_DECnet
    {AF_DECnet, FamilyDECnet},
#endif /* AF_DECnet */
#ifdef     AF_CHAOS
    {AF_CHAOS, FamilyChaos},
#endif /* AF_CHAOS */
#ifdef    AF_INET
    {AF_INET, FamilyInternet}
#endif
};

/*
 * called when authorization is enabled, to remove the
 * local host from the access list
 */

DisableLocalHost ()
{
    LocalHostEnabled = FALSE;
}

EnableLocalHost ()
{
    if (!UsingXdmcp)
	LocalHostEnabled = TRUE;
}

/*
 * called at init time when XDMCP will be used; xdmcp always
 * adds local hosts manually when needed
 */

AccessUsingXdmcp ()
{
    UsingXdmcp = TRUE;
    LocalHostEnabled = FALSE;
}

#define FAMILIES ((sizeof familyMap)/(sizeof familyMap[0]))

#if defined (hpux) && ! defined (HAS_IFREQ)
/* Define this host for access control.  Find all the hosts the OS knows about 
 * for this fd and add them to the selfhosts list.
 * HPUX version - hpux does not have SIOCGIFCONF ioctl;
 */
DefineSelf (fd)
    int fd;
{
    register int n;
    int	len;
    caddr_t	addr;
    int		family;
    register HOST	*host;

    struct utsname name;
    register struct hostent  *hp;

    union {
	struct  sockaddr   sa;
	struct  sockaddr_in  in;
    } saddr;
	
    struct	sockaddr_in	*inetaddr;

    /* Why not use gethostname()?  Well, at least on my system, I've had to
     * make an ugly kernel patch to get a name longer than 8 characters, and
     * uname() lets me access to the whole string (it smashes release, you
     * see), whereas gethostname() kindly truncates it for me.
     */
    uname(&name);
    hp = gethostbyname (name.nodename);
    if (hp != NULL)
    {
	saddr.sa.sa_family = hp->h_addrtype;
	inetaddr = (struct sockaddr_in *) (&(saddr.sa));
	acopy ( hp->h_addr, &(inetaddr->sin_addr), hp->h_length);
	len = sizeof(saddr.sa);
	family = ConvertAddr ( &(saddr.sa), &len, &addr);
	if ( family > 0)
	{
	    for (host = selfhosts;
		 host && !addrEqual (family, addr, len, host);
		 host = host->next) ;
	    if (!host)
	    {
		/* add this host to the host list.	*/
		host = (HOST *) xalloc (sizeof (HOST));
		if (host)
		{
		    host->family = family;
		    host->len = len;
		    acopy ( addr, host->addr, len);
		    host->next = selfhosts;
		    selfhosts = host;
		}
	    }
	}
    }
}

#else
/* Define this host for access control.  Find all the hosts the OS knows about 
 * for this fd and add them to the selfhosts list.
 */
DefineSelf (fd)
    int fd;
{
    char		buf[2048];
    struct ifconf	ifc;
    register int	n;
    int 		len;
    pointer 		addr;
    int 		family;
    register HOST 	*host;
    register struct ifreq *ifr;
    
    ifc.ifc_len = sizeof (buf);
    ifc.ifc_buf = buf;
    if (ioctl (fd, (int) SIOCGIFCONF, (pointer) &ifc) < 0)
        Error ("Getting interface configuration");
    for (ifr = ifc.ifc_req, n = ifc.ifc_len / sizeof (struct ifreq); --n >= 0;
     ifr++)
    {
	len = sizeof(ifr->ifr_addr);
#ifdef DNETCONN
	/*
	 * this is ugly but SIOCGIFCONF returns decnet addresses in
	 * a different form from other decnet calls
	 */
	if (ifr->ifr_addr.sa_family == AF_DECnet)
	{
		len = sizeof (struct dn_naddr);
		addr = (pointer)ifr->ifr_addr.sa_data;
		family = AF_DECnet;
	} else
#endif /* DNETCONN */
        if ((family = ConvertAddr (&ifr->ifr_addr, &len, &addr)) <= 0)
	    continue;
        for (host = selfhosts;
 	     host && !addrEqual (family, addr, len, host);
	     host = host->next)
	    ;
        if (host)
	    continue;
        host = (HOST *) xalloc (sizeof (HOST));
	if (host)
	{
	    host->family = family;
	    host->len = len;
	    acopy(addr, host->addr, len);
	    host->next = selfhosts;
	    selfhosts = host;
	}
#ifdef XDMCP
	{
	    struct sockaddr broad_addr;

	    XdmcpRegisterConnection (FamilyInternet, (char *)addr, len);
	    broad_addr = ifr->ifr_addr;
	    ((struct sockaddr_in *) &broad_addr)->sin_addr.s_addr =
		htonl (INADDR_BROADCAST);
#ifdef SIOCGIFBRDADDR
	    {
	    	struct ifreq    broad_req;
    
	    	broad_req = *ifr;
		if (ioctl (fd, SIOCGIFFLAGS, (char *) &broad_req) != -1 &&
		    (broad_req.ifr_flags & IFF_BROADCAST) &&
		    (broad_req.ifr_flags & IFF_UP)
		    )
		{
		    broad_req = *ifr;
		    if (ioctl (fd, SIOCGIFBRDADDR, &broad_req) != -1)
			broad_addr = broad_req.ifr_addr;
		    else
			continue;
		}
		else
		    continue;
	    }
#endif
	    XdmcpRegisterBroadcastAddress ((struct sockaddr_in *) &broad_addr);
	}
#endif
    }
}
#endif /* hpux && !HAS_IFREQ */

AddLocalHosts ()
{
    HOST    *self;

    for (self = selfhosts; self; self = self->next)
	NewHost (self->family, self->addr);
}

/* Reset access control list to initial hosts */
ResetHosts (display)
    char *display;
{
    register HOST	*host;
    char 		hostname[120];
    char		fname[32];
    FILE		*fd;
    char		*ptr;
    union {
        struct sockaddr	sa;
#ifdef TCPCONN
        struct sockaddr_in in;
#endif /* TCPCONN */
#ifdef DNETCONN
        struct sockaddr_dn dn;
#endif
    } 			saddr;
#ifdef DNETCONN
    struct nodeent 	*np;
    struct dn_naddr 	dnaddr, *dnaddrp, *dnet_addr();
#endif
    int			family;
    int			len;
    pointer		addr;
    register struct hostent *hp;

    AccessEnabled = DEFAULT_ACCESS_CONTROL;
    while (host = validhosts)
    {
        validhosts = host->next;
        xfree (host);
    }
    if (LocalHostEnabled)
	AddLocalHosts ();
    strcpy (fname, "/etc/X");
    strcat (fname, display);
    strcat (fname, ".hosts");
    if (fd = fopen (fname, "r")) 
    {
        while (fgets (hostname, sizeof (hostname), fd))
	{
    	if (ptr = index (hostname, '\n'))
    	    *ptr = 0;
#ifdef DNETCONN
    	if ((ptr = index (hostname, ':')) && (*(ptr + 1) == ':'))
	{
    	    /* node name (DECnet names end in "::") */
    	    *ptr = 0;
    	    if (dnaddrp = dnet_addr(hostname))
	    {
    		    /* allow nodes to be specified by address */
    		    NewHost ((short) AF_DECnet, (pointer) dnaddrp);
    	    }
	    else
	    {
    		if (np = getnodebyname (hostname))
		{
    		    /* node was specified by name */
    		    saddr.sa.sa_family = np->n_addrtype;
		    len = sizeof(saddr.sa);
    		    if ((family = ConvertAddr (&saddr.sa, &len, &addr)) ==
		      AF_DECnet)
		    {
    			bzero ((pointer) &dnaddr, sizeof (dnaddr));
    			dnaddr.a_len = np->n_length;
    			acopy (np->n_addr, dnaddr.a_addr, np->n_length);
    			NewHost (family, (pointer) &dnaddr);
    		    }
    		}
    	    }
    	}
	else
	{
#endif /* DNETCONN */
#ifdef TCPCONN
    	    /* host name */
    	    if (hp = gethostbyname (hostname))
	    {
    		saddr.sa.sa_family = hp->h_addrtype;
		len = sizeof(saddr.sa);
    		if ((family = ConvertAddr (&saddr.sa, &len, &addr)) > 0)
#ifdef h_addr				/* new 4.3bsd version of gethostent */
		{
		    char **list;

		    /* iterate over the addresses */
		    for (list = hp->h_addr_list; *list; list++)
			NewHost (family, (pointer)*list);
		}
#else
    		    NewHost (family, (pointer)hp->h_addr);
#endif

    	    }
#endif /* TCPCONN */
#ifdef DNETCONN
    	}	
#endif /* DNETCONN */
        }
        fclose (fd);
    }
}

static Bool
AuthorizedClient(client)
    ClientPtr client;
{
    int    		alen, family;
    struct sockaddr	from;
    pointer		addr;
    register HOST	*host;

    alen = sizeof (from);
    if (!getpeername (((OsCommPtr)client->osPrivate)->fd, &from, &alen))
    {
        if ((family = ConvertAddr (&from, &alen, &addr)) >= 0)
	{
	    if (family == 0)
		return TRUE;
	    for (host = selfhosts; host; host = host->next)
	    {
		if (addrEqual (family, addr, alen, host))
		    return TRUE;
	    }
	}
    }
    return FALSE;
}

/* Add a host to the access control list.  This is the external interface
 * called from the dispatcher */

int
AddHost (client, family, length, pAddr)
    ClientPtr		client;
    int                 family;
    unsigned            length;        /* of bytes in pAddr */
    pointer             pAddr;
{
    int			len;
    register HOST	*host;
    int                 unixFamily;

    if (!AuthorizedClient(client))
	return(BadAccess);
    unixFamily = UnixFamily(family);
    if ((len = CheckFamily (DONT_CHECK, unixFamily)) < 0)
    {
	client->errorValue = family;
        return(-len);
    }

    if (len != length)
    {
	client->errorValue = length;
        return(BadValue);
    }
    for (host = validhosts; host; host = host->next)
    {
        if (addrEqual (unixFamily, pAddr, len, host))
    	    return (Success);
    }
    host = (HOST *) xalloc (sizeof (HOST));
    if (!host)
	return(BadAlloc);
    host->family = unixFamily;
    host->len = len;
    acopy(pAddr, host->addr, len);
    host->next = validhosts;
    validhosts = host;
    return (Success);
}

/* Add a host to the access control list. This is the internal interface 
 * called when starting or resetting the server */
static void
NewHost (family, addr)
    short	family;
    pointer	addr;
{
    int		len;
    register HOST *host;

    if ((len = CheckFamily (DONT_CHECK, family)) < 0)
        return;
    for (host = validhosts; host; host = host->next)
    {
        if (addrEqual (family, addr, len, host))
	    return;
    }
    host = (HOST *) xalloc (sizeof (HOST));
    if (host)
    {
	host->family = family;
	host->len = len;
	acopy(addr, host->addr, len);
	host->next = validhosts;
	validhosts = host;
    }
}

/* Remove a host from the access control list */

int
RemoveHost (client, family, length, pAddr)
    ClientPtr		client;
    int                 family;
    unsigned            length;        /* of bytes in pAddr */
    pointer             pAddr;
{
    int			len,
                        unixFamily;
    register HOST	*host, **prev;

    if (!AuthorizedClient(client))
	return(BadAccess);
    unixFamily = UnixFamily(family);
    if ((len = CheckFamily (DONT_CHECK, unixFamily)) < 0)
    {
	client->errorValue = family;
        return(-len);
    }
    if (len != length)
    {
	client->errorValue = length;
        return(BadValue);
    }
    for (prev = &validhosts;
         (host = *prev) && (!addrEqual (unixFamily, pAddr, len, host));
         prev = &host->next)
        ;
    if (host)
    {
        *prev = host->next;
        xfree (host);
    }
    return (Success);
}

/* Get all hosts in the access control list */
int
GetHosts (data, pnHosts, pLen, pEnabled)
    pointer		*data;
    int			*pnHosts;
    int			*pLen;
    BOOL		*pEnabled;
{
    int			len;
    register int 	n = 0;
    register pointer	ptr;
    register HOST	*host;
    int			nHosts = 0;
    int			*lengths = (int *) NULL;
    int			*newlens;

    *pEnabled = AccessEnabled ? EnableAccess : DisableAccess;
    for (host = validhosts; host; host = host->next)
    {
        if ((len = CheckFamily (DONT_CHECK, host->family)) < 0)
            return (-1);
	newlens = (int *) xrealloc(lengths, (nHosts + 1) * sizeof(int));
	if (!newlens)
	{
	    xfree(lengths);
	    return(BadAlloc);
	}
	lengths = newlens;
	lengths[nHosts++] = len;
	n += (((len + 3) >> 2) << 2) + sizeof(xHostEntry);
    }
    if (n)
    {
        *data = ptr = (pointer) xalloc (n);
	if (!ptr)
	{
	    xfree(lengths);
	    return(BadAlloc);
	}
	nHosts = 0;
        for (host = validhosts; host; host = host->next)
	{

	    len = lengths[nHosts++];
	    ((xHostEntry *)ptr)->family = XFamily(host->family);
	    ((xHostEntry *)ptr)->length = len;
	    ptr += sizeof(xHostEntry);
	    acopy (host->addr, ptr, len);
	    ptr += ((len + 3) >> 2) << 2;
        }
    } else {
	*data = NULL;
    }
    *pnHosts = nHosts;
    *pLen = n;
    xfree(lengths);
    return(Success);
}

/* Check for valid address family, and for local host if client modification.
 * Return address length.
 */

static int
CheckFamily (connection, family)
    int			connection;
    int			family;
{
    struct sockaddr	from;
    int	 		alen;
    pointer		addr;
    register HOST	*host;
    int 		len;

    switch (family)
    {
#ifdef TCPCONN
      case AF_INET:
        len = sizeof (struct in_addr);
        break;
#endif 
#ifdef DNETCONN
      case AF_DECnet:
        len = sizeof (struct dn_naddr);
        break;
#endif
      default:
        return (-BadValue);
    }
    if (connection == DONT_CHECK)
        return (len);
    alen = sizeof (from);
    if (!getpeername (connection, &from, &alen))
    {
        if ((family = ConvertAddr (&from, &alen, &addr)) >= 0)
	{
	    if (family == 0)
		return (len);
	    for (host = selfhosts; host; host = host->next)
	    {
		if (addrEqual (family, addr, alen, host))
		    return (len);
	    }
	}
    }
    /* Bad Access */
    return (-1);
}

/* Check if a host is not in the access control list. 
 * Returns 1 if host is invalid, 0 if we've found it. */

InvalidHost (saddr, len)
    register struct sockaddr	*saddr;
    int				len;
{
    int 			family;
    pointer			addr;
    register HOST 		*selfhost, *host;
    if ((family = ConvertAddr (saddr, &len, &addr)) < 0)
        return (1);
    if (family == 0)
    {
	if (!LocalHostEnabled)
 	{
	    /*
	     * check to see if any local address is enabled.  This 
	     * implicitly enables local connections.
	     */
	    for (selfhost = selfhosts; selfhost; selfhost=selfhost->next)
 	    {
		for (host = validhosts; host; host=host->next)
		{
		    if (addrEqual (selfhost->family, selfhost->addr,
				   selfhost->len, host))
			return 0;
		}
	    }
	    return 1;
	} else
	    return (0);
    }
    if (!AccessEnabled)   /* just let them in */
        return(0);    
    for (host = validhosts; host; host = host->next)
    {
        if (addrEqual (family, addr, len, host))
    	    return (0);
    }
    return (1);
}

static int
ConvertAddr (saddr, len, addr)
    register struct sockaddr	*saddr;
    int				*len;
    pointer			*addr;
{
    if (*len == 0)
        return (0);
    switch (saddr->sa_family)
    {
      case AF_UNSPEC:
#ifdef UNIXCONN
      case AF_UNIX:
#endif
        return (0);

#ifdef TCPCONN
      case AF_INET:
        *len = sizeof (struct in_addr);
        *addr = (pointer) &(((struct sockaddr_in *) saddr)->sin_addr);
        return (AF_INET);
#endif

#ifdef DNETCONN
      case AF_DECnet:
        *len = sizeof (struct dn_naddr);
        *addr = (pointer) &(((struct sockaddr_dn *) saddr)->sdn_add);
        return (AF_DECnet);
#endif

      default:
        break;
    }
    return (-1);
}

int
ChangeAccessControl(client, fEnabled)
    ClientPtr client;
    int fEnabled;
{
    if (!AuthorizedClient(client))
	return BadAccess;
    AccessEnabled = fEnabled;
    return Success;
}

static int XFamily(af)
    int af;
{
    int i;
    for (i = 0; i < FAMILIES; i++)
        if (familyMap[i].af == af)
            return familyMap[i].xf;
    return -1;
}

static int UnixFamily(xf)
    int xf;
{
    int i;
    for (i = 0; i < FAMILIES; i++)
        if (familyMap[i].xf == xf)
            return familyMap[i].af;
    return -1;
}