/*      $NetBSD: auth_unix.c,v 1.18 2000/07/06 03:03:30 christos Exp $  */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2009, Sun Microsystems, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 * - Redistributions of source code must retain the above copyright notice, 
 *   this list of conditions and the following disclaimer.
 * - 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.
 * - Neither the name of Sun Microsystems, Inc. nor the names of its 
 *   contributors may be used to endorse or promote products derived 
 *   from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 THE COPYRIGHT HOLDER 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.
 */

/*
 * auth_unix.c, Implements UNIX style authentication parameters.
 *
 * Copyright (C) 1984, Sun Microsystems, Inc.
 *
 * The system is very weak.  The client uses no encryption for it's
 * credentials and only sends null verifiers.  The server sends backs
 * null verifiers or optionally a verifier that suggests a new short hand
 * for the credentials.
 *
 */

#include "namespace.h"
#include "reentrant.h"
#include <sys/param.h>

#include <assert.h>
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#include <rpc/types.h>
#include <rpc/xdr.h>
#include <rpc/auth.h>
#include <rpc/auth_unix.h>
#include "un-namespace.h"
#include "mt_misc.h"

/* auth_unix.c */
static void authunix_nextverf (AUTH *);
static bool_t authunix_marshal (AUTH *, XDR *);
static bool_t authunix_validate (AUTH *, struct opaque_auth *);
static bool_t authunix_refresh (AUTH *, void *);
static void authunix_destroy (AUTH *);
static void marshal_new_auth (AUTH *);
static struct auth_ops *authunix_ops (void);

/*
 * This struct is pointed to by the ah_private field of an auth_handle.
 */
struct audata {
        struct opaque_auth      au_origcred;    /* original credentials */
        struct opaque_auth      au_shcred;      /* short hand cred */
        u_long                  au_shfaults;    /* short hand cache faults */
        char                    au_marshed[MAX_AUTH_BYTES];
        u_int                   au_mpos;        /* xdr pos at end of marshed */
};
#define AUTH_PRIVATE(auth)      ((struct audata *)auth->ah_private)

/*
 * Create a unix style authenticator.
 * Returns an auth handle with the given stuff in it.
 */
AUTH *
authunix_create(char *machname, u_int uid, u_int gid, int len, u_int *aup_gids)
{
        struct authunix_parms aup;
        char mymem[MAX_AUTH_BYTES];
        struct timeval now;
        XDR xdrs;
        AUTH *auth;
        struct audata *au;

        /*
         * Allocate and set up auth handle
         */
        au = NULL;
        auth = mem_alloc(sizeof(*auth));
#ifndef _KERNEL
        if (auth == NULL) {
                warnx("authunix_create: out of memory");
                goto cleanup_authunix_create;
        }
#endif
        au = mem_alloc(sizeof(*au));
#ifndef _KERNEL
        if (au == NULL) {
                warnx("authunix_create: out of memory");
                goto cleanup_authunix_create;
        }
#endif
        auth->ah_ops = authunix_ops();
        auth->ah_private = (caddr_t)au;
        auth->ah_verf = au->au_shcred = _null_auth;
        au->au_shfaults = 0;
        au->au_origcred.oa_base = NULL;

        /*
         * fill in param struct from the given params
         */
        (void)gettimeofday(&now, NULL);
        aup.aup_time = now.tv_sec;
        aup.aup_machname = machname;
        aup.aup_uid = uid;
        aup.aup_gid = gid;
        aup.aup_len = (u_int)len;
        aup.aup_gids = aup_gids;

        /*
         * Serialize the parameters into origcred
         */
        xdrmem_create(&xdrs, mymem, MAX_AUTH_BYTES, XDR_ENCODE);
        if (! xdr_authunix_parms(&xdrs, &aup)) 
                abort();
        au->au_origcred.oa_length = len = XDR_GETPOS(&xdrs);
        au->au_origcred.oa_flavor = AUTH_UNIX;
#ifdef _KERNEL
        au->au_origcred.oa_base = mem_alloc((u_int) len);
#else
        if ((au->au_origcred.oa_base = mem_alloc((u_int) len)) == NULL) {
                warnx("authunix_create: out of memory");
                goto cleanup_authunix_create;
        }
#endif
        memmove(au->au_origcred.oa_base, mymem, (size_t)len);

        /*
         * set auth handle to reflect new cred.
         */
        auth->ah_cred = au->au_origcred;
        marshal_new_auth(auth);
        return (auth);
#ifndef _KERNEL
 cleanup_authunix_create:
        if (auth)
                mem_free(auth, sizeof(*auth));
        if (au) {
                if (au->au_origcred.oa_base)
                        mem_free(au->au_origcred.oa_base, (u_int)len);
                mem_free(au, sizeof(*au));
        }
        return (NULL);
#endif
}

/*
 * Returns an auth handle with parameters determined by doing lots of
 * syscalls.
 */
AUTH *
authunix_create_default(void)
{
        AUTH *auth;
        int ngids;
        long ngids_max;
        char machname[MAXHOSTNAMELEN + 1];
        uid_t uid;
        gid_t gid;
        gid_t *gids;

        ngids_max = sysconf(_SC_NGROUPS_MAX) + 1;
        gids = malloc(sizeof(gid_t) * ngids_max);
        if (gids == NULL)
                return (NULL);

        if (gethostname(machname, sizeof machname) == -1)
                abort();
        machname[sizeof(machname) - 1] = 0;
        uid = geteuid();
        gid = getegid();
        if ((ngids = getgroups(ngids_max, gids)) < 0)
                abort();
        if (ngids > NGRPS)
                ngids = NGRPS;
        /* XXX: interface problem; we should translate from uid_t and gid_t */
        auth = authunix_create(machname, uid, gid, ngids, gids);
        free(gids);
        return (auth);
}

/*
 * authunix operations
 */

/* ARGSUSED */
static void
authunix_nextverf(AUTH *auth)
{
        /* no action necessary */
}

static bool_t
authunix_marshal(AUTH *auth, XDR *xdrs)
{
        struct audata *au;

        assert(auth != NULL);
        assert(xdrs != NULL);

        au = AUTH_PRIVATE(auth);
        return (XDR_PUTBYTES(xdrs, au->au_marshed, au->au_mpos));
}

static bool_t
authunix_validate(AUTH *auth, struct opaque_auth *verf)
{
        struct audata *au;
        XDR xdrs;

        assert(auth != NULL);
        assert(verf != NULL);

        if (verf->oa_flavor == AUTH_SHORT) {
                au = AUTH_PRIVATE(auth);
                xdrmem_create(&xdrs, verf->oa_base, verf->oa_length,
                    XDR_DECODE);

                if (au->au_shcred.oa_base != NULL) {
                        mem_free(au->au_shcred.oa_base,
                            au->au_shcred.oa_length);
                        au->au_shcred.oa_base = NULL;
                }
                if (xdr_opaque_auth(&xdrs, &au->au_shcred)) {
                        auth->ah_cred = au->au_shcred;
                } else {
                        xdrs.x_op = XDR_FREE;
                        (void)xdr_opaque_auth(&xdrs, &au->au_shcred);
                        au->au_shcred.oa_base = NULL;
                        auth->ah_cred = au->au_origcred;
                }
                marshal_new_auth(auth);
        }
        return (TRUE);
}

static bool_t
authunix_refresh(AUTH *auth, void *dummy)
{
        struct audata *au = AUTH_PRIVATE(auth);
        struct authunix_parms aup;
        struct timeval now;
        XDR xdrs;
        int stat;

        assert(auth != NULL);

        if (auth->ah_cred.oa_base == au->au_origcred.oa_base) {
                /* there is no hope.  Punt */
                return (FALSE);
        }
        au->au_shfaults ++;

        /* first deserialize the creds back into a struct authunix_parms */
        aup.aup_machname = NULL;
        aup.aup_gids = NULL;
        xdrmem_create(&xdrs, au->au_origcred.oa_base,
            au->au_origcred.oa_length, XDR_DECODE);
        stat = xdr_authunix_parms(&xdrs, &aup);
        if (! stat)
                goto done;

        /* update the time and serialize in place */
        (void)gettimeofday(&now, NULL);
        aup.aup_time = now.tv_sec;
        xdrs.x_op = XDR_ENCODE;
        XDR_SETPOS(&xdrs, 0);
        stat = xdr_authunix_parms(&xdrs, &aup);
        if (! stat)
                goto done;
        auth->ah_cred = au->au_origcred;
        marshal_new_auth(auth);
done:
        /* free the struct authunix_parms created by deserializing */
        xdrs.x_op = XDR_FREE;
        (void)xdr_authunix_parms(&xdrs, &aup);
        XDR_DESTROY(&xdrs);
        return (stat);
}

static void
authunix_destroy(AUTH *auth)
{
        struct audata *au;

        assert(auth != NULL);

        au = AUTH_PRIVATE(auth);
        mem_free(au->au_origcred.oa_base, au->au_origcred.oa_length);

        if (au->au_shcred.oa_base != NULL)
                mem_free(au->au_shcred.oa_base, au->au_shcred.oa_length);

        mem_free(auth->ah_private, sizeof(struct audata));

        if (auth->ah_verf.oa_base != NULL)
                mem_free(auth->ah_verf.oa_base, auth->ah_verf.oa_length);

        mem_free(auth, sizeof(*auth));
}

/*
 * Marshals (pre-serializes) an auth struct.
 * sets private data, au_marshed and au_mpos
 */
static void
marshal_new_auth(AUTH *auth)
{
        XDR     xdr_stream;
        XDR     *xdrs = &xdr_stream;
        struct audata *au;

        assert(auth != NULL);

        au = AUTH_PRIVATE(auth);
        xdrmem_create(xdrs, au->au_marshed, MAX_AUTH_BYTES, XDR_ENCODE);
        if ((! xdr_opaque_auth(xdrs, &(auth->ah_cred))) ||
            (! xdr_opaque_auth(xdrs, &(auth->ah_verf))))
                warnx("auth_none.c - Fatal marshalling problem");
        else
                au->au_mpos = XDR_GETPOS(xdrs);
        XDR_DESTROY(xdrs);
}

static struct auth_ops *
authunix_ops(void)
{
        static struct auth_ops ops;

        /* VARIABLES PROTECTED BY ops_lock: ops */

        mutex_lock(&ops_lock);
        if (ops.ah_nextverf == NULL) {
                ops.ah_nextverf = authunix_nextverf;
                ops.ah_marshal = authunix_marshal;
                ops.ah_validate = authunix_validate;
                ops.ah_refresh = authunix_refresh;
                ops.ah_destroy = authunix_destroy;
        }
        mutex_unlock(&ops_lock);
        return (&ops);
}