/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */

/*
 * Portions of this source code were derived from Berkeley 4.3 BSD
 * under license from the Regents of the University of California.
 */

/*
 * auth_loopb.c, implements UNIX style authentication parameters in the
 * kernel.  Interfaces with svc_auth_loopback on the server.  See
 * auth_loopb.c for the user level implementation of the loopback auth.
 *
 */

#include <sys/param.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/systm.h>
#include <sys/user.h>
#include <sys/proc.h>
#include <sys/utsname.h>
#include <sys/cred.h>
#include <sys/kmem.h>
#include <sys/sysmacros.h>
#include <sys/cmn_err.h>

#include <rpc/types.h>
#include <rpc/xdr.h>
#include <rpc/auth.h>
#include <rpc/auth_unix.h>
#include <rpc/clnt.h>
#include <rpc/rpc_msg.h>

/*
 * Unix authenticator operations vector
 */
static void     authloopback_nextverf(AUTH *);
static bool_t   authloopback_marshal(AUTH *, XDR *, struct cred *);
static bool_t   authloopback_validate(AUTH *, struct opaque_auth *);
static bool_t   authloopback_refresh(AUTH *, struct rpc_msg *, cred_t *);
static void     authloopback_destroy(AUTH *);

static struct auth_ops authloopback_ops = {
        authloopback_nextverf,
        authloopback_marshal,
        authloopback_validate,
        authloopback_refresh,
        authloopback_destroy,
        authany_wrap,
        authany_unwrap
};

/*
 * Create a kernel unix style authenticator.
 * Returns an auth handle.
 */
AUTH *
authloopback_create(void)
{
        /*
         * Allocate and set up auth handle
         */
        return (kmem_cache_alloc(authloopback_cache, KM_SLEEP));
}

/*
 *  The constructor of the authloopback_cache.
 */
/* ARGSUSED */
int
authloopback_init(void *buf, void *cdrarg, int kmflags)
{
        AUTH *auth = (AUTH *)buf;

        auth->ah_ops = &authloopback_ops;
        auth->ah_cred.oa_flavor = AUTH_LOOPBACK;
        auth->ah_verf = _null_auth;

        return (0);
}

/*
 * authloopback operations
 */
/* ARGSUSED */
static void
authloopback_nextverf(AUTH *auth)
{

        /* no action necessary */
}

static bool_t
authloopback_marshal(AUTH *auth, XDR *xdrs, struct cred *cr)
{
        char *sercred;
        XDR xdrm;
        bool_t ret;
        uint32_t gidlen, credsize, namelen, rounded_namelen;
        int32_t *ptr;
        char *nodename = uts_nodename();
        uint32_t maxgidlen;
        uint_t startpos;

        ASSERT(xdrs->x_op == XDR_ENCODE);
        ASSERT(auth->ah_cred.oa_flavor == AUTH_LOOPBACK);
        ASSERT(auth->ah_verf.oa_flavor == AUTH_NONE);
        ASSERT(auth->ah_verf.oa_length == 0);

        /*
         * First we try a fast path to get through
         * this very common operation.
         */
        namelen = (uint32_t)strlen(nodename);
        if (namelen > MAX_MACHINE_NAME)
                return (FALSE);
        rounded_namelen = RNDUP(namelen);

        /*
         * NFIELDS is a number of the following fields we are going to encode:
         *   - stamp
         *   - strlen(machinename)
         *   - uid
         *   - gid
         *   - the number of gids
         */
#define NFIELDS 5
        CTASSERT(NFIELDS * BYTES_PER_XDR_UNIT + RNDUP(MAX_MACHINE_NAME) <=
            MAX_AUTH_BYTES);
        maxgidlen = (MAX_AUTH_BYTES - NFIELDS * BYTES_PER_XDR_UNIT -
            rounded_namelen) / BYTES_PER_XDR_UNIT;

        gidlen = crgetngroups(cr);
        if (gidlen > maxgidlen)
                return (FALSE);

        credsize = NFIELDS * BYTES_PER_XDR_UNIT + rounded_namelen +
            gidlen * BYTES_PER_XDR_UNIT;
        ASSERT(credsize <= MAX_AUTH_BYTES);
#undef  NFIELDS

        /*
         * We need to marshal both cred and verf parts of the rpc_msg body
         * (call_body).  For the cred part we need to inline the auth_flavor
         * and the opaque auth body size.  Then we inline the credsize bytes of
         * the opaque auth body for the cred part.  Finally we add the
         * AUTH_NONE verifier (its auth_flavor and the opaque auth body size).
         */
        ptr = XDR_INLINE(xdrs, 2 * BYTES_PER_XDR_UNIT + credsize +
            2 * BYTES_PER_XDR_UNIT);
        if (ptr != NULL) {
                /*
                 * We can do the fast path.
                 */
                const gid_t *gp = crgetgroups(cr);

                IXDR_PUT_U_INT32(ptr, AUTH_LOOPBACK);   /* cred flavor */
                IXDR_PUT_U_INT32(ptr, credsize);        /* cred len */

                IXDR_PUT_INT32(ptr, gethrestime_sec());
                IXDR_PUT_U_INT32(ptr, namelen);
                bcopy(nodename, ptr, namelen);
                if ((rounded_namelen - namelen) > 0)
                        bzero((char *)ptr + namelen, rounded_namelen - namelen);
                ptr += rounded_namelen / BYTES_PER_XDR_UNIT;
                IXDR_PUT_U_INT32(ptr, crgetuid(cr));
                IXDR_PUT_U_INT32(ptr, crgetgid(cr));
                IXDR_PUT_U_INT32(ptr, gidlen);
                while (gidlen-- > 0)
                        IXDR_PUT_U_INT32(ptr, *gp++);

                IXDR_PUT_U_INT32(ptr, AUTH_NONE);       /* verf flavor */
                IXDR_PUT_U_INT32(ptr, 0);               /* verf len */

                return (TRUE);
        }

        sercred = kmem_alloc(MAX_AUTH_BYTES, KM_SLEEP);

        /*
         * Serialize the auth body data into sercred.
         */
        xdrmem_create(&xdrm, sercred, MAX_AUTH_BYTES, XDR_ENCODE);
        startpos = XDR_GETPOS(&xdrm);
        if (!xdr_authloopback(&xdrm, cr)) {
                printf("authloopback_marshal: xdr_authloopback failed\n");
                ret = FALSE;
                goto done;
        }

        /*
         * Make opaque auth credentials to point at the serialized auth body
         * data.
         */
        auth->ah_cred.oa_base = sercred;
        auth->ah_cred.oa_length = XDR_GETPOS(&xdrm) - startpos;
        ASSERT(auth->ah_cred.oa_length <= MAX_AUTH_BYTES);

        /*
         * serialize credentials and verifier (null)
         */
        if ((xdr_opaque_auth(xdrs, &(auth->ah_cred))) &&
            (xdr_opaque_auth(xdrs, &(auth->ah_verf))))
                ret = TRUE;
        else
                ret = FALSE;

done:
        XDR_DESTROY(&xdrm);
        kmem_free(sercred, MAX_AUTH_BYTES);

        return (ret);
}

/* ARGSUSED */
static bool_t
authloopback_validate(AUTH *auth, struct opaque_auth *verf)
{
        return (TRUE);
}

/* ARGSUSED */
static bool_t
authloopback_refresh(AUTH *auth, struct rpc_msg *msg, cred_t *cr)
{
        return (FALSE);
}

static void
authloopback_destroy(register AUTH *auth)
{
        kmem_cache_free(authloopback_cache, auth);
}