/*      $NetBSD: security.c,v 1.5 2000/06/08 09:01:05 fvdl Exp $        */

#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <rpc/rpc.h>
#include <rpc/rpcb_prot.h>
#include <rpc/pmap_prot.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <syslog.h>
#include <netdb.h>

/*
 * XXX for special case checks in check_callit.
 */
#include <rpcsvc/mount.h>
#include <rpcsvc/rquota.h>
#include <rpcsvc/nfs_prot.h>
#include <rpcsvc/yp.h>
#include <rpcsvc/ypclnt.h>
#include <rpcsvc/yppasswd.h>

#include "rpcbind.h"

#ifdef LIBWRAP
# include <tcpd.h>
#ifndef LIBWRAP_ALLOW_FACILITY
# define LIBWRAP_ALLOW_FACILITY LOG_AUTH
#endif
#ifndef LIBWRAP_ALLOW_SEVERITY
# define LIBWRAP_ALLOW_SEVERITY LOG_INFO
#endif
#ifndef LIBWRAP_DENY_FACILITY
# define LIBWRAP_DENY_FACILITY LOG_AUTH
#endif
#ifndef LIBWRAP_DENY_SEVERITY
# define LIBWRAP_DENY_SEVERITY LOG_WARNING
#endif
int allow_severity = LIBWRAP_ALLOW_FACILITY|LIBWRAP_ALLOW_SEVERITY;
int deny_severity = LIBWRAP_DENY_FACILITY|LIBWRAP_DENY_SEVERITY;
#endif

#ifndef PORTMAP_LOG_FACILITY
# define PORTMAP_LOG_FACILITY LOG_AUTH
#endif
#ifndef PORTMAP_LOG_SEVERITY
# define PORTMAP_LOG_SEVERITY LOG_INFO
#endif
int log_severity = PORTMAP_LOG_FACILITY|PORTMAP_LOG_SEVERITY;

extern int verboselog;

int 
check_access(SVCXPRT *xprt, rpcproc_t proc, void *args, unsigned int rpcbvers)
{
        struct netbuf *caller = svc_getrpccaller(xprt);
        struct sockaddr *addr = (struct sockaddr *)caller->buf;
#ifdef LIBWRAP
        struct request_info req;
#endif
        rpcprog_t prog = 0;
        rpcb *rpcbp;
        struct pmap *pmap;

        /*
         * The older PMAP_* equivalents have the same numbers, so
         * they are accounted for here as well.
         */
        switch (proc) {
        case RPCBPROC_GETADDR:
        case RPCBPROC_SET:
        case RPCBPROC_UNSET:
                if (rpcbvers > PMAPVERS) {
                        rpcbp = (rpcb *)args;
                        prog = rpcbp->r_prog;
                } else {
                        pmap = (struct pmap *)args;
                        prog = pmap->pm_prog;
                }
                if (proc == RPCBPROC_GETADDR)
                        break;
                if (!insecure && !is_loopback(caller)) {
                        if (verboselog)
                                logit(log_severity, addr, proc, prog,
                                    " declined (non-loopback sender)");
                        return 0;
                }
                break;
        case RPCBPROC_CALLIT:
        case RPCBPROC_INDIRECT:
        case RPCBPROC_DUMP:
        case RPCBPROC_GETTIME:
        case RPCBPROC_UADDR2TADDR:
        case RPCBPROC_TADDR2UADDR:
        case RPCBPROC_GETVERSADDR:
        case RPCBPROC_GETADDRLIST:
        case RPCBPROC_GETSTAT:
        default:
                break;
        }

#ifdef LIBWRAP
        if (libwrap && addr->sa_family != AF_LOCAL) {
                request_init(&req, RQ_DAEMON, "rpcbind", RQ_CLIENT_SIN, addr,
                    0);
                sock_methods(&req);
                if(!hosts_access(&req)) {
                        logit(deny_severity, addr, proc, prog,
                            ": request from unauthorized host");
                        return 0;
                }
        }
#endif
        if (verboselog)
                logit(log_severity, addr, proc, prog, "");
        return 1;
}

int
is_loopback(struct netbuf *nbuf)
{
        struct sockaddr *addr = (struct sockaddr *)nbuf->buf;
        struct sockaddr_in *sin;
#ifdef INET6
        struct sockaddr_in6 *sin6;
#endif

        switch (addr->sa_family) {
        case AF_INET:
                if (!oldstyle_local)
                        return 0;
                sin = (struct sockaddr_in *)addr;
                return ((sin->sin_addr.s_addr == htonl(INADDR_LOOPBACK)) &&
                    (ntohs(sin->sin_port) < IPPORT_RESERVED));
#ifdef INET6
        case AF_INET6:
                if (!oldstyle_local)
                        return 0;
                sin6 = (struct sockaddr_in6 *)addr;
                return (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr) &&
                    (ntohs(sin6->sin6_port) < IPV6PORT_RESERVED));
#endif
        case AF_LOCAL:
        case AF_NETLINK:
                return 1;
        default:
                break;
        }
        
        return 0;
}


/* logit - report events of interest via the syslog daemon */
void
logit(int severity, struct sockaddr *addr, rpcproc_t procnum, rpcprog_t prognum,
      const char *text)
{
        const char *procname;
        char    procbuf[32];
        char   *progname;
        char    progbuf[32];
        char fromname[NI_MAXHOST];
        struct rpcent *rpc;
        static const char *procmap[] = {
        /* RPCBPROC_NULL */             "null",
        /* RPCBPROC_SET */              "set",
        /* RPCBPROC_UNSET */            "unset",
        /* RPCBPROC_GETADDR */          "getport/addr",
        /* RPCBPROC_DUMP */             "dump",
        /* RPCBPROC_CALLIT */           "callit",
        /* RPCBPROC_GETTIME */          "gettime",
        /* RPCBPROC_UADDR2TADDR */      "uaddr2taddr",
        /* RPCBPROC_TADDR2UADDR */      "taddr2uaddr",
        /* RPCBPROC_GETVERSADDR */      "getversaddr",
        /* RPCBPROC_INDIRECT */         "indirect",
        /* RPCBPROC_GETADDRLIST */      "getaddrlist",
        /* RPCBPROC_GETSTAT */          "getstat"
        };
   
        /*
         * Fork off a process or the portmap daemon might hang while
         * getrpcbynumber() or syslog() does its thing.
         */

        if (fork() == 0) {
                setproctitle("logit");

                /* Try to map program number to name. */

                if (prognum == 0) {
                        progname = "";
                } else if ((rpc = getrpcbynumber((int) prognum))) {
                        progname = rpc->r_name;
                } else {
                        snprintf(progname = progbuf, sizeof(progbuf), "%u",
                            (unsigned)prognum);
                }

                /* Try to map procedure number to name. */

                if (procnum >= (sizeof procmap / sizeof (char *))) {
                        snprintf(procbuf, sizeof procbuf, "%u",
                            (unsigned)procnum);
                        procname = procbuf;
                } else
                        procname = procmap[procnum];

                /* Write syslog record. */

                if (addr->sa_family == AF_LOCAL)
                        strcpy(fromname, "local");
                else
                        getnameinfo(addr, addr->sa_len, fromname,
                            sizeof fromname, NULL, 0, NI_NUMERICHOST);

                syslog(severity, "connect from %s to %s(%s)%s",
                        fromname, procname, progname, text);
                _exit(0);
        }
}

int
check_callit(SVCXPRT *xprt, struct r_rmtcall_args *args, int versnum __unused)
{
        struct sockaddr *sa = (struct sockaddr *)svc_getrpccaller(xprt)->buf;

        /*
         * Always allow calling NULLPROC
         */
        if (args->rmt_proc == 0)
                return 1;

        /*
         * XXX - this special casing sucks.
         */
        switch (args->rmt_prog) {
        case RPCBPROG:
                /*
                 * Allow indirect calls to ourselves in insecure mode.
                 * The is_loopback checks aren't useful then anyway.
                 */
                if (!insecure)
                        goto deny;
                break;
        case MOUNTPROG:
                if (args->rmt_proc != MOUNTPROC_MNT &&
                    args->rmt_proc != MOUNTPROC_UMNT)
                        break;
                goto deny;
        case YPBINDPROG:
                if (args->rmt_proc != YPBINDPROC_SETDOM)
                        break;
                /* FALLTHROUGH */
        case YPPASSWDPROG:
        case NFS_PROGRAM:
        case RQUOTAPROG:
                goto deny;
        case YPPROG:
                switch (args->rmt_proc) {
                case YPPROC_ALL:
                case YPPROC_MATCH:
                case YPPROC_FIRST:
                case YPPROC_NEXT:
                        goto deny;
                default:
                        break;
                }
        default:
                break;
        }

        return 1;
deny:
#ifdef LIBWRAP
        logit(deny_severity, sa, args->rmt_proc, args->rmt_prog,
            ": indirect call not allowed");
#else
        logit(0, sa, args->rmt_proc, args->rmt_prog,
            ": indirect call not allowed");
#endif
        return 0;
}