/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2008 Doug Rabson
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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_gss.c

  RPCSEC_GSS client routines.
  
  Copyright (c) 2000 The Regents of the University of Michigan.
  All rights reserved.

  Copyright (c) 2000 Dug Song <dugsong@UMICH.EDU>.
  All rights reserved, all wrongs reversed.

  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. Neither the name of the University 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 ``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 REGENTS 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: auth_gss.c,v 1.32 2002/01/15 15:43:00 andros Exp $
*/

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/hash.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/kobj.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/refcount.h>
#include <sys/sx.h>
#include <sys/ucred.h>

#include <rpc/rpc.h>
#include <rpc/rpcsec_gss.h>

#include <kgssapi/krb5/kcrypto.h>

#include "rpcsec_gss_int.h"

static void     rpc_gss_nextverf(AUTH*);
static bool_t   rpc_gss_marshal(AUTH *, uint32_t, XDR *, struct mbuf *);
static bool_t   rpc_gss_init(AUTH *auth, rpc_gss_options_ret_t *options_ret);
static bool_t   rpc_gss_refresh(AUTH *, void *);
static bool_t   rpc_gss_validate(AUTH *, uint32_t, struct opaque_auth *,
    struct mbuf **);
static void     rpc_gss_destroy(AUTH *);
static void     rpc_gss_destroy_context(AUTH *, bool_t);

static const struct auth_ops rpc_gss_ops = {
        .ah_nextverf =  rpc_gss_nextverf,
        .ah_marshal =   rpc_gss_marshal,
        .ah_validate =  rpc_gss_validate,
        .ah_refresh =   rpc_gss_refresh,
        .ah_destroy =   rpc_gss_destroy,
};

enum rpcsec_gss_state {
        RPCSEC_GSS_START,
        RPCSEC_GSS_CONTEXT,
        RPCSEC_GSS_ESTABLISHED,
        RPCSEC_GSS_DESTROYING
};

struct rpc_pending_request {
        uint32_t                pr_xid;         /* XID of rpc */
        uint32_t                pr_seq;         /* matching GSS seq */
        LIST_ENTRY(rpc_pending_request) pr_link;
};
LIST_HEAD(rpc_pending_request_list, rpc_pending_request);

struct rpc_gss_data {
        volatile u_int          gd_refs;        /* number of current users */
        struct mtx              gd_lock;
        uint32_t                gd_hash;
        AUTH                    *gd_auth;       /* link back to AUTH */
        struct ucred            *gd_ucred;      /* matching local cred */
        char                    *gd_principal;  /* server principal name */
        char                    *gd_clntprincipal; /* client principal name */
        rpc_gss_options_req_t   gd_options;     /* GSS context options */
        enum rpcsec_gss_state   gd_state;       /* connection state */
        gss_buffer_desc         gd_verf;        /* save GSS_S_COMPLETE
                                                 * NULL RPC verifier to
                                                 * process at end of
                                                 * context negotiation */
        CLIENT                  *gd_clnt;       /* client handle */
        gss_OID                 gd_mech;        /* mechanism to use */
        gss_qop_t               gd_qop;         /* quality of protection */
        gss_ctx_id_t            gd_ctx;         /* context id */
        struct rpc_gss_cred     gd_cred;        /* client credentials */
        uint32_t                gd_seq;         /* next sequence number */
        u_int                   gd_win;         /* sequence window */
        struct rpc_pending_request_list gd_reqs;
        TAILQ_ENTRY(rpc_gss_data) gd_link;
        TAILQ_ENTRY(rpc_gss_data) gd_alllink;
};
TAILQ_HEAD(rpc_gss_data_list, rpc_gss_data);

#define AUTH_PRIVATE(auth)      ((struct rpc_gss_data *)auth->ah_private)

static struct timeval AUTH_TIMEOUT = { 25, 0 };

#define RPC_GSS_HASH_SIZE       11
#define RPC_GSS_MAX             256

VNET_DEFINE_STATIC(struct rpc_gss_data_list *, rpc_gss_cache);
VNET_DEFINE_STATIC(struct rpc_gss_data_list, rpc_gss_all);
VNET_DEFINE_STATIC(struct sx, rpc_gss_lock);
VNET_DEFINE_STATIC(int, rpc_gss_count);

static AUTH *rpc_gss_seccreate_int(CLIENT *, struct ucred *, const char *,
    const char *, gss_OID, rpc_gss_service_t, u_int, rpc_gss_options_req_t *,
    rpc_gss_options_ret_t *);

static void
rpc_gss_hashinit(void *dummy __unused)
{
        int i;

        VNET(rpc_gss_cache) = mem_alloc(sizeof(struct rpc_gss_data_list) *
            RPC_GSS_HASH_SIZE);
        for (i = 0; i < RPC_GSS_HASH_SIZE; i++)
                TAILQ_INIT(&VNET(rpc_gss_cache)[i]);
        TAILQ_INIT(&VNET(rpc_gss_all));
        sx_init(&VNET(rpc_gss_lock), "rpc_gss_lock");
}
VNET_SYSINIT(rpc_gss_hashinit, SI_SUB_VNET_DONE, SI_ORDER_ANY,
    rpc_gss_hashinit, NULL);

static void
rpc_gss_hashinit_cleanup(void *dummy __unused)
{

        rpc_gss_secpurge(NULL);
        mem_free(VNET(rpc_gss_cache), sizeof(struct rpc_gss_data_list) *
            RPC_GSS_HASH_SIZE);
        sx_destroy(&VNET(rpc_gss_lock));
}
VNET_SYSUNINIT(rpc_gss_hashinit_cleanup, SI_SUB_VNET_DONE, SI_ORDER_ANY,
    rpc_gss_hashinit_cleanup, NULL);

static uint32_t
rpc_gss_hash(const char *principal, gss_OID mech,
    struct ucred *cred, rpc_gss_service_t service)
{
        uint32_t h;

        h = HASHSTEP(HASHINIT, cred->cr_uid);
        h = hash32_str(principal, h);
        h = hash32_buf(mech->elements, mech->length, h);
        h = HASHSTEP(h, (int) service);

        return (h % RPC_GSS_HASH_SIZE);
}

/*
 * Simplified interface to create a security association for the
 * current thread's * ucred.
 */
AUTH *
rpc_gss_secfind(CLIENT *clnt, struct ucred *cred, const char *principal,
    gss_OID mech_oid, rpc_gss_service_t service)
{
        uint32_t                h, th;
        AUTH                    *auth;
        struct rpc_gss_data     *gd, *tgd;
        rpc_gss_options_ret_t   options;

        CURVNET_ASSERT_SET();
        if (VNET(rpc_gss_count) > RPC_GSS_MAX) {
                while (VNET(rpc_gss_count) > RPC_GSS_MAX) {
                        sx_xlock(&VNET(rpc_gss_lock));
                        tgd = TAILQ_FIRST(&VNET(rpc_gss_all));
                        th = tgd->gd_hash;
                        TAILQ_REMOVE(&VNET(rpc_gss_cache)[th], tgd, gd_link);
                        TAILQ_REMOVE(&VNET(rpc_gss_all), tgd, gd_alllink);
                        VNET(rpc_gss_count)--;
                        sx_xunlock(&VNET(rpc_gss_lock));
                        AUTH_DESTROY(tgd->gd_auth);
                }
        }

        /*
         * See if we already have an AUTH which matches.
         */
        h = rpc_gss_hash(principal, mech_oid, cred, service);

again:
        sx_slock(&VNET(rpc_gss_lock));
        TAILQ_FOREACH(gd, &VNET(rpc_gss_cache)[h], gd_link) {
                if (gd->gd_ucred->cr_uid == cred->cr_uid
                    && !strcmp(gd->gd_principal, principal)
                    && gd->gd_mech == mech_oid
                    && gd->gd_cred.gc_svc == service) {
                        refcount_acquire(&gd->gd_refs);
                        if (sx_try_upgrade(&VNET(rpc_gss_lock))) {
                                /*
                                 * Keep rpc_gss_all LRU sorted.
                                 */
                                TAILQ_REMOVE(&VNET(rpc_gss_all), gd,
                                    gd_alllink);
                                TAILQ_INSERT_TAIL(&VNET(rpc_gss_all), gd,
                                    gd_alllink);
                                sx_xunlock(&VNET(rpc_gss_lock));
                        } else {
                                sx_sunlock(&VNET(rpc_gss_lock));
                        }

                        /*
                         * If the state != ESTABLISHED, try and initialize
                         * the authenticator again. This will happen if the
                         * user's credentials have expired. It may succeed now,
                         * if they have done a kinit or similar.
                         */
                        if (gd->gd_state != RPCSEC_GSS_ESTABLISHED) {
                                memset(&options, 0, sizeof (options));
                                (void) rpc_gss_init(gd->gd_auth, &options);
                        }
                        return (gd->gd_auth);
                }
        }
        sx_sunlock(&VNET(rpc_gss_lock));

        /*
         * We missed in the cache - create a new association.
         */
        auth = rpc_gss_seccreate_int(clnt, cred, NULL, principal, mech_oid,
            service, GSS_C_QOP_DEFAULT, NULL, NULL);
        if (!auth)
                return (NULL);

        gd = AUTH_PRIVATE(auth);
        gd->gd_hash = h;
        
        sx_xlock(&VNET(rpc_gss_lock));
        TAILQ_FOREACH(tgd, &VNET(rpc_gss_cache)[h], gd_link) {
                if (tgd->gd_ucred->cr_uid == cred->cr_uid
                    && !strcmp(tgd->gd_principal, principal)
                    && tgd->gd_mech == mech_oid
                    && tgd->gd_cred.gc_svc == service) {
                        /*
                         * We lost a race to create the AUTH that
                         * matches this cred.
                         */
                        sx_xunlock(&VNET(rpc_gss_lock));
                        AUTH_DESTROY(auth);
                        goto again;
                }
        }

        VNET(rpc_gss_count)++;
        TAILQ_INSERT_TAIL(&VNET(rpc_gss_cache)[h], gd, gd_link);
        TAILQ_INSERT_TAIL(&VNET(rpc_gss_all), gd, gd_alllink);
        refcount_acquire(&gd->gd_refs); /* one for the cache, one for user */
        sx_xunlock(&VNET(rpc_gss_lock));

        return (auth);
}

void
rpc_gss_secpurge(CLIENT *clnt)
{
        uint32_t                h;
        struct rpc_gss_data     *gd, *tgd;

        CURVNET_ASSERT_SET();
        TAILQ_FOREACH_SAFE(gd, &VNET(rpc_gss_all), gd_alllink, tgd) {
                if (clnt == NULL || gd->gd_clnt == clnt) {
                        sx_xlock(&VNET(rpc_gss_lock));
                        h = gd->gd_hash;
                        TAILQ_REMOVE(&VNET(rpc_gss_cache)[h], gd, gd_link);
                        TAILQ_REMOVE(&VNET(rpc_gss_all), gd, gd_alllink);
                        VNET(rpc_gss_count)--;
                        sx_xunlock(&VNET(rpc_gss_lock));
                        AUTH_DESTROY(gd->gd_auth);
                }
        }
}

AUTH *
rpc_gss_seccreate(CLIENT *clnt, struct ucred *cred, const char *clnt_principal,
    const char *principal, const char *mechanism, rpc_gss_service_t service,
    const char *qop, rpc_gss_options_req_t *options_req,
    rpc_gss_options_ret_t *options_ret)
{
        gss_OID                 oid;
        u_int                   qop_num;

        /*
         * Bail out now if we don't know this mechanism.
         */
        if (!rpc_gss_mech_to_oid(mechanism, &oid))
                return (NULL);

        if (qop) {
                if (!rpc_gss_qop_to_num(qop, mechanism, &qop_num))
                        return (NULL);
        } else {
                qop_num = GSS_C_QOP_DEFAULT;
        }

        return (rpc_gss_seccreate_int(clnt, cred, clnt_principal, principal,
                oid, service, qop_num, options_req, options_ret));
}

void
rpc_gss_refresh_auth(AUTH *auth)
{
        struct rpc_gss_data     *gd;
        rpc_gss_options_ret_t   options;

        gd = AUTH_PRIVATE(auth);
        /*
         * If the state != ESTABLISHED, try and initialize
         * the authenticator again. This will happen if the
         * user's credentials have expired. It may succeed now,
         * if they have done a kinit or similar.
         */
        if (gd->gd_state != RPCSEC_GSS_ESTABLISHED) {
                memset(&options, 0, sizeof (options));
                (void) rpc_gss_init(auth, &options);
        }
}

static AUTH *
rpc_gss_seccreate_int(CLIENT *clnt, struct ucred *cred,
    const char *clnt_principal, const char *principal, gss_OID mech_oid,
    rpc_gss_service_t service, u_int qop_num,
    rpc_gss_options_req_t *options_req, rpc_gss_options_ret_t *options_ret)
{
        AUTH                    *auth;
        rpc_gss_options_ret_t   options;
        struct rpc_gss_data     *gd;

        /*
         * If the caller doesn't want the options, point at local
         * storage to simplify the code below.
         */
        if (!options_ret)
                options_ret = &options;

        /*
         * Default service is integrity.
         */
        if (service == rpc_gss_svc_default)
                service = rpc_gss_svc_integrity;

        memset(options_ret, 0, sizeof(*options_ret));

        rpc_gss_log_debug("in rpc_gss_seccreate()");
        
        memset(&rpc_createerr, 0, sizeof(rpc_createerr));
        
        auth = mem_alloc(sizeof(*auth));
        if (auth == NULL) {
                rpc_createerr.cf_stat = RPC_SYSTEMERROR;
                rpc_createerr.cf_error.re_errno = ENOMEM;
                return (NULL);
        }
        gd = mem_alloc(sizeof(*gd));
        if (gd == NULL) {
                rpc_createerr.cf_stat = RPC_SYSTEMERROR;
                rpc_createerr.cf_error.re_errno = ENOMEM;
                mem_free(auth, sizeof(*auth));
                return (NULL);
        }

        auth->ah_ops = &rpc_gss_ops;
        auth->ah_private = (caddr_t) gd;
        auth->ah_cred.oa_flavor = RPCSEC_GSS;
        
        refcount_init(&gd->gd_refs, 1);
        mtx_init(&gd->gd_lock, "gd->gd_lock", NULL, MTX_DEF);
        gd->gd_auth = auth;
        gd->gd_ucred = crdup(cred);
        gd->gd_principal = strdup(principal, M_RPC);
        if (clnt_principal != NULL)
                gd->gd_clntprincipal = strdup(clnt_principal, M_RPC);
        else
                gd->gd_clntprincipal = NULL;


        if (options_req) {
                gd->gd_options = *options_req;
        } else {
                gd->gd_options.req_flags = GSS_C_MUTUAL_FLAG;
                gd->gd_options.time_req = 0;
                gd->gd_options.my_cred = GSS_C_NO_CREDENTIAL;
                gd->gd_options.input_channel_bindings = NULL;
        }
        CLNT_ACQUIRE(clnt);
        gd->gd_clnt = clnt;
        gd->gd_ctx = GSS_C_NO_CONTEXT;
        gd->gd_mech = mech_oid;
        gd->gd_qop = qop_num;

        gd->gd_cred.gc_version = RPCSEC_GSS_VERSION;
        gd->gd_cred.gc_proc = RPCSEC_GSS_INIT;
        gd->gd_cred.gc_seq = 0;
        gd->gd_cred.gc_svc = service;
        LIST_INIT(&gd->gd_reqs);
        
        if (!rpc_gss_init(auth, options_ret)) {
                goto bad;
        }
        
        return (auth);

 bad:
        AUTH_DESTROY(auth);
        return (NULL);
}

bool_t
rpc_gss_set_defaults(AUTH *auth, rpc_gss_service_t service, const char *qop)
{
        struct rpc_gss_data     *gd;
        u_int                   qop_num;
        const char              *mechanism;

        gd = AUTH_PRIVATE(auth);
        if (!rpc_gss_oid_to_mech(gd->gd_mech, &mechanism)) {
                return (FALSE);
        }

        if (qop) {
                if (!rpc_gss_qop_to_num(qop, mechanism, &qop_num)) {
                        return (FALSE);
                }
        } else {
                qop_num = GSS_C_QOP_DEFAULT;
        }

        gd->gd_cred.gc_svc = service;
        gd->gd_qop = qop_num;
        return (TRUE);
}

static void
rpc_gss_purge_xid(struct rpc_gss_data *gd, uint32_t xid)
{
        struct rpc_pending_request *pr, *npr;
        struct rpc_pending_request_list reqs;

        LIST_INIT(&reqs);
        mtx_lock(&gd->gd_lock);
        LIST_FOREACH_SAFE(pr, &gd->gd_reqs, pr_link, npr) {
                if (pr->pr_xid == xid) {
                        LIST_REMOVE(pr, pr_link);
                        LIST_INSERT_HEAD(&reqs, pr, pr_link);
                }
        }

        mtx_unlock(&gd->gd_lock);

        LIST_FOREACH_SAFE(pr, &reqs, pr_link, npr) {
                mem_free(pr, sizeof(*pr));
        }
}

static uint32_t
rpc_gss_alloc_seq(struct rpc_gss_data *gd)
{
        uint32_t seq;

        mtx_lock(&gd->gd_lock);
        seq = gd->gd_seq;
        gd->gd_seq++;
        mtx_unlock(&gd->gd_lock);

        return (seq);
}

static void
rpc_gss_nextverf(__unused AUTH *auth)
{

        /* not used */
}

static bool_t
rpc_gss_marshal(AUTH *auth, uint32_t xid, XDR *xdrs, struct mbuf *args)
{
        struct rpc_gss_data     *gd;
        struct rpc_pending_request *pr;
        uint32_t                 seq;
        XDR                      tmpxdrs;
        struct rpc_gss_cred      gsscred;
        char                     credbuf[MAX_AUTH_BYTES];
        struct opaque_auth       creds, verf;
        gss_buffer_desc          rpcbuf, checksum;
        OM_uint32                maj_stat, min_stat;
        bool_t                   xdr_stat;

        rpc_gss_log_debug("in rpc_gss_marshal()");

        gd = AUTH_PRIVATE(auth);
        
        gsscred = gd->gd_cred;
        seq = rpc_gss_alloc_seq(gd);
        gsscred.gc_seq = seq;

        xdrmem_create(&tmpxdrs, credbuf, sizeof(credbuf), XDR_ENCODE);
        if (!xdr_rpc_gss_cred(&tmpxdrs, &gsscred)) {
                XDR_DESTROY(&tmpxdrs);
                _rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR, ENOMEM);
                return (FALSE);
        }
        creds.oa_flavor = RPCSEC_GSS;
        creds.oa_base = credbuf;
        creds.oa_length = XDR_GETPOS(&tmpxdrs);
        XDR_DESTROY(&tmpxdrs);

        xdr_opaque_auth(xdrs, &creds);

        if (gd->gd_cred.gc_proc == RPCSEC_GSS_INIT ||
            gd->gd_cred.gc_proc == RPCSEC_GSS_CONTINUE_INIT) {
                if (!xdr_opaque_auth(xdrs, &_null_auth)) {
                        _rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR, ENOMEM);
                        return (FALSE);
                }
                return (xdr_putmbuf(xdrs, args));
        } else {
                /*
                 * Keep track of this XID + seq pair so that we can do
                 * the matching gss_verify_mic in AUTH_VALIDATE.
                 */
                pr = mem_alloc(sizeof(struct rpc_pending_request));
                mtx_lock(&gd->gd_lock);
                pr->pr_xid = xid;
                pr->pr_seq = seq;
                LIST_INSERT_HEAD(&gd->gd_reqs, pr, pr_link);
                mtx_unlock(&gd->gd_lock);

                /*
                 * Checksum serialized RPC header, up to and including
                 * credential. For the in-kernel environment, we
                 * assume that our XDR stream is on a contiguous
                 * memory buffer (e.g. an mbuf).
                 */
                rpcbuf.length = XDR_GETPOS(xdrs);
                XDR_SETPOS(xdrs, 0);
                rpcbuf.value = XDR_INLINE(xdrs, rpcbuf.length);

                maj_stat = gss_get_mic(&min_stat, gd->gd_ctx, gd->gd_qop,
                    &rpcbuf, &checksum);

                if (maj_stat != GSS_S_COMPLETE) {
                        rpc_gss_log_status("gss_get_mic", gd->gd_mech,
                            maj_stat, min_stat);
                        if (maj_stat == GSS_S_CONTEXT_EXPIRED) {
                                rpc_gss_destroy_context(auth, TRUE);
                        }
                        _rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR, EPERM);
                        return (FALSE);
                }

                verf.oa_flavor = RPCSEC_GSS;
                verf.oa_base = checksum.value;
                verf.oa_length = checksum.length;

                xdr_stat = xdr_opaque_auth(xdrs, &verf);
                gss_release_buffer(&min_stat, &checksum);
                if (!xdr_stat) {
                        _rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR, ENOMEM);
                        return (FALSE);
                }
                if (gd->gd_state != RPCSEC_GSS_ESTABLISHED ||
                    gd->gd_cred.gc_svc == rpc_gss_svc_none) {
                        return (xdr_putmbuf(xdrs, args));
                } else {
                        if (!xdr_rpc_gss_wrap_data(&args,
                                gd->gd_ctx, gd->gd_qop, gd->gd_cred.gc_svc,
                                seq))
                                return (FALSE);
                        return (xdr_putmbuf(xdrs, args));
                }
        }

        return (TRUE);
}

static bool_t
rpc_gss_validate(AUTH *auth, uint32_t xid, struct opaque_auth *verf,
    struct mbuf **resultsp)
{
        struct rpc_gss_data     *gd;
        struct rpc_pending_request *pr, *npr;
        struct rpc_pending_request_list reqs;
        gss_qop_t               qop_state;
        uint32_t                num, seq;
        gss_buffer_desc         signbuf, checksum;
        OM_uint32               maj_stat, min_stat;

        rpc_gss_log_debug("in rpc_gss_validate()");
        
        gd = AUTH_PRIVATE(auth);

        /*
         * The client will call us with a NULL verf when it gives up
         * on an XID.
         */
        if (!verf) {
                rpc_gss_purge_xid(gd, xid);
                return (TRUE);
        }

        if (gd->gd_state == RPCSEC_GSS_CONTEXT) {
                /*
                 * Save the on the wire verifier to validate last INIT
                 * phase packet after decode if the major status is
                 * GSS_S_COMPLETE.
                 */
                if (gd->gd_verf.value)
                        xdr_free((xdrproc_t) xdr_gss_buffer_desc,
                            (char *) &gd->gd_verf);
                gd->gd_verf.value = mem_alloc(verf->oa_length);
                if (gd->gd_verf.value == NULL) {
                        printf("gss_validate: out of memory\n");
                        _rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR, ENOMEM);
                        m_freem(*resultsp);
                        *resultsp = NULL;
                        return (FALSE);
                }
                memcpy(gd->gd_verf.value, verf->oa_base, verf->oa_length);
                gd->gd_verf.length = verf->oa_length;

                return (TRUE);
        }

        /*
         * We need to check the verifier against all the requests
         * we've send for this XID - for unreliable protocols, we
         * retransmit with the same XID but different sequence
         * number. We temporarily take this set of requests out of the
         * list so that we can work through the list without having to
         * hold the lock.
         */
        mtx_lock(&gd->gd_lock);
        LIST_INIT(&reqs);
        LIST_FOREACH_SAFE(pr, &gd->gd_reqs, pr_link, npr) {
                if (pr->pr_xid == xid) {
                        LIST_REMOVE(pr, pr_link);
                        LIST_INSERT_HEAD(&reqs, pr, pr_link);
                }
        }
        mtx_unlock(&gd->gd_lock);
        LIST_FOREACH(pr, &reqs, pr_link) {
                if (pr->pr_xid == xid) {
                        seq = pr->pr_seq;
                        num = htonl(seq);
                        signbuf.value = &num;
                        signbuf.length = sizeof(num);
        
                        checksum.value = verf->oa_base;
                        checksum.length = verf->oa_length;
        
                        maj_stat = gss_verify_mic(&min_stat, gd->gd_ctx,
                            &signbuf, &checksum, &qop_state);
                        if (maj_stat != GSS_S_COMPLETE
                            || qop_state != gd->gd_qop) {
                                continue;
                        }
                        if (maj_stat == GSS_S_CONTEXT_EXPIRED) {
                                rpc_gss_destroy_context(auth, TRUE);
                                break;
                        }
                        //rpc_gss_purge_reqs(gd, seq);
                        LIST_FOREACH_SAFE(pr, &reqs, pr_link, npr)
                                mem_free(pr, sizeof(*pr));

                        if (gd->gd_cred.gc_svc == rpc_gss_svc_none) {
                                return (TRUE);
                        } else {
                                if (!xdr_rpc_gss_unwrap_data(resultsp,
                                        gd->gd_ctx, gd->gd_qop,
                                        gd->gd_cred.gc_svc, seq)) {
                                        return (FALSE);
                                }
                        }
                        return (TRUE);
                }
        }

        /*
         * We didn't match - put back any entries for this XID so that
         * a future call to validate can retry.
         */
        mtx_lock(&gd->gd_lock);
        LIST_FOREACH_SAFE(pr, &reqs, pr_link, npr) {
                LIST_REMOVE(pr, pr_link);
                LIST_INSERT_HEAD(&gd->gd_reqs, pr, pr_link);
        }
        mtx_unlock(&gd->gd_lock);

        /*
         * Nothing matches - give up.
         */
        _rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR, EPERM);
        m_freem(*resultsp);
        *resultsp = NULL;
        return (FALSE);
}

static bool_t
rpc_gss_init(AUTH *auth, rpc_gss_options_ret_t *options_ret)
{
        struct thread           *td = curthread;
        struct ucred            *crsave;
        struct rpc_gss_data     *gd;
        struct rpc_gss_init_res  gr;
        gss_buffer_desc         principal_desc;
        gss_buffer_desc         *recv_tokenp, recv_token, send_token;
        gss_name_t              name;
        OM_uint32                maj_stat, min_stat, call_stat;
        const char              *mech;
        struct rpc_callextra     ext;
        gss_OID                 mech_oid;
        gss_OID_set             mechlist;
        static enum krb_imp     my_krb_imp = KRBIMP_UNKNOWN;

        CURVNET_ASSERT_SET();
        rpc_gss_log_debug("in rpc_gss_refresh()");
        
        gd = AUTH_PRIVATE(auth);
        
        mtx_lock(&gd->gd_lock);
        /*
         * If the context isn't in START state, someone else is
         * refreshing - we wait till they are done. If they fail, they
         * will put the state back to START and we can try (most
         * likely to also fail).
         */
        while (gd->gd_state != RPCSEC_GSS_START
            && gd->gd_state != RPCSEC_GSS_ESTABLISHED) {
                msleep(gd, &gd->gd_lock, 0, "gssstate", 0);
        }
        if (gd->gd_state == RPCSEC_GSS_ESTABLISHED) {
                mtx_unlock(&gd->gd_lock);
                return (TRUE);
        }
        gd->gd_state = RPCSEC_GSS_CONTEXT;
        mtx_unlock(&gd->gd_lock);

        gd->gd_cred.gc_proc = RPCSEC_GSS_INIT;
        gd->gd_cred.gc_seq = 0;

        /*
         * For KerberosV, if there is a client principal name, that implies
         * that this is a host based initiator credential in the default
         * keytab file. For this case, it is necessary to do a
         * gss_acquire_cred(). When this is done, the gssd daemon will
         * do the equivalent of "kinit -k" to put a TGT for the name in
         * the credential cache file for the gssd daemon.
         */
        if (gd->gd_clntprincipal != NULL &&
            rpc_gss_mech_to_oid("kerberosv5", &mech_oid) &&
            gd->gd_mech == mech_oid) {
                /* Get rid of any old credential. */
                if (gd->gd_options.my_cred != GSS_C_NO_CREDENTIAL) {
                        gss_release_cred(&min_stat, &gd->gd_options.my_cred);
                        gd->gd_options.my_cred = GSS_C_NO_CREDENTIAL;
                }
        
                /*
                 * The mechanism must be set to KerberosV for acquisition
                 * of credentials to work reliably.
                 */
                maj_stat = gss_create_empty_oid_set(&min_stat, &mechlist);
                if (maj_stat != GSS_S_COMPLETE) {
                        options_ret->major_status = maj_stat;
                        options_ret->minor_status = min_stat;
                        goto out;
                }
                maj_stat = gss_add_oid_set_member(&min_stat, gd->gd_mech,
                    &mechlist);
                if (maj_stat != GSS_S_COMPLETE) {
                        options_ret->major_status = maj_stat;
                        options_ret->minor_status = min_stat;
                        gss_release_oid_set(&min_stat, &mechlist);
                        goto out;
                }
        
                principal_desc.value = (void *)gd->gd_clntprincipal;
                principal_desc.length = strlen(gd->gd_clntprincipal);
                maj_stat = gss_import_name(&min_stat, &principal_desc,
                    GSS_C_NT_HOSTBASED_SERVICE, &name);
                if (maj_stat != GSS_S_COMPLETE) {
                        options_ret->major_status = maj_stat;
                        options_ret->minor_status = min_stat;
                        gss_release_oid_set(&min_stat, &mechlist);
                        goto out;
                }
                /* Acquire the credentials. */
                maj_stat = gss_acquire_cred(&min_stat, name, 0,
                    mechlist, GSS_C_INITIATE,
                    &gd->gd_options.my_cred, NULL, NULL);
                gss_release_name(&min_stat, &name);
                gss_release_oid_set(&min_stat, &mechlist);
                if (maj_stat != GSS_S_COMPLETE) {
                        options_ret->major_status = maj_stat;
                        options_ret->minor_status = min_stat;
                        goto out;
                }
        }

        principal_desc.value = (void *)gd->gd_principal;
        principal_desc.length = strlen(gd->gd_principal);
        maj_stat = gss_import_name(&min_stat, &principal_desc,
            GSS_C_NT_HOSTBASED_SERVICE, &name);
        if (maj_stat != GSS_S_COMPLETE) {
                options_ret->major_status = maj_stat;
                options_ret->minor_status = min_stat;
                goto out;
        }

        if (my_krb_imp == KRBIMP_UNKNOWN) {
                maj_stat = gss_supports_lucid(&min_stat, NULL);
                if (maj_stat == GSS_S_COMPLETE)
                        my_krb_imp = KRBIMP_MIT;
                else
                        my_krb_imp = KRBIMP_HEIMDALV1;
        }

        /* GSS context establishment loop. */
        memset(&recv_token, 0, sizeof(recv_token));
        memset(&gr, 0, sizeof(gr));
        memset(options_ret, 0, sizeof(*options_ret));
        options_ret->major_status = GSS_S_FAILURE;
        recv_tokenp = GSS_C_NO_BUFFER;
        
        for (;;) {
                crsave = td->td_ucred;
                td->td_ucred = gd->gd_ucred;
                if (my_krb_imp == KRBIMP_MIT)
                        maj_stat = gss_init_sec_context_lucid_v1(&min_stat,
                            gd->gd_options.my_cred,
                            &gd->gd_ctx,
                            name,
                            gd->gd_mech,
                            gd->gd_options.req_flags,
                            gd->gd_options.time_req,
                            gd->gd_options.input_channel_bindings,
                            recv_tokenp,
                            &gd->gd_mech,       /* used mech */
                            &send_token,
                            &options_ret->ret_flags,
                            &options_ret->time_req);
                else
                        maj_stat = gss_init_sec_context(&min_stat,
                            gd->gd_options.my_cred,
                            &gd->gd_ctx,
                            name,
                            gd->gd_mech,
                            gd->gd_options.req_flags,
                            gd->gd_options.time_req,
                            gd->gd_options.input_channel_bindings,
                            recv_tokenp,
                            &gd->gd_mech,       /* used mech */
                            &send_token,
                            &options_ret->ret_flags,
                            &options_ret->time_req);
                td->td_ucred = crsave;
                
                /*
                 * Free the token which we got from the server (if
                 * any).  Remember that this was allocated by XDR, not
                 * GSS-API.
                 */
                if (recv_tokenp != GSS_C_NO_BUFFER) {
                        xdr_free((xdrproc_t) xdr_gss_buffer_desc,
                            (char *) &recv_token);
                        recv_tokenp = GSS_C_NO_BUFFER;
                }
                if (gd->gd_mech && rpc_gss_oid_to_mech(gd->gd_mech, &mech)) {
                        strlcpy(options_ret->actual_mechanism,
                            mech,
                            sizeof(options_ret->actual_mechanism));
                }
                if (maj_stat != GSS_S_COMPLETE &&
                    maj_stat != GSS_S_CONTINUE_NEEDED) {
                        rpc_gss_log_status("gss_init_sec_context", gd->gd_mech,
                            maj_stat, min_stat);
                        options_ret->major_status = maj_stat;
                        options_ret->minor_status = min_stat;
                        break;
                }
                if (send_token.length != 0) {
                        memset(&gr, 0, sizeof(gr));
                        
                        bzero(&ext, sizeof(ext));
                        ext.rc_auth = auth;
                        call_stat = CLNT_CALL_EXT(gd->gd_clnt, &ext, NULLPROC,
                            (xdrproc_t)xdr_gss_buffer_desc,
                            &send_token,
                            (xdrproc_t)xdr_rpc_gss_init_res,
                            (caddr_t)&gr, AUTH_TIMEOUT);
                        
                        gss_release_buffer(&min_stat, &send_token);
                        
                        if (call_stat != RPC_SUCCESS)
                                break;

                        if (gr.gr_major != GSS_S_COMPLETE &&
                            gr.gr_major != GSS_S_CONTINUE_NEEDED) {
                                rpc_gss_log_status("server reply", gd->gd_mech,
                                    gr.gr_major, gr.gr_minor);
                                options_ret->major_status = gr.gr_major;
                                options_ret->minor_status = gr.gr_minor;
                                break;
                        }
                        
                        /*
                         * Save the server's gr_handle value, freeing
                         * what we have already (remember that this
                         * was allocated by XDR, not GSS-API).
                         */
                        if (gr.gr_handle.length != 0) {
                                xdr_free((xdrproc_t) xdr_gss_buffer_desc,
                                    (char *) &gd->gd_cred.gc_handle);
                                gd->gd_cred.gc_handle = gr.gr_handle;
                        }

                        /*
                         * Save the server's token as well.
                         */
                        if (gr.gr_token.length != 0) {
                                recv_token = gr.gr_token;
                                recv_tokenp = &recv_token;
                        }

                        /*
                         * Since we have copied out all the bits of gr
                         * which XDR allocated for us, we don't need
                         * to free it.
                         */
                        gd->gd_cred.gc_proc = RPCSEC_GSS_CONTINUE_INIT;
                }

                if (maj_stat == GSS_S_COMPLETE) {
                        gss_buffer_desc   bufin;
                        u_int seq, qop_state = 0;

                        /* 
                         * gss header verifier,
                         * usually checked in gss_validate
                         */
                        seq = htonl(gr.gr_win);
                        bufin.value = (unsigned char *)&seq;
                        bufin.length = sizeof(seq);

                        maj_stat = gss_verify_mic(&min_stat, gd->gd_ctx,
                            &bufin, &gd->gd_verf, &qop_state);

                        if (maj_stat != GSS_S_COMPLETE ||
                            qop_state != gd->gd_qop) {
                                rpc_gss_log_status("gss_verify_mic", gd->gd_mech,
                                    maj_stat, min_stat);
                                if (maj_stat == GSS_S_CONTEXT_EXPIRED) {
                                        rpc_gss_destroy_context(auth, TRUE);
                                }
                                _rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR,
                                    EPERM);
                                options_ret->major_status = maj_stat;
                                options_ret->minor_status = min_stat;
                                break;
                        }

                        options_ret->major_status = GSS_S_COMPLETE;
                        options_ret->minor_status = 0;
                        options_ret->rpcsec_version = gd->gd_cred.gc_version;
                        options_ret->gss_context = gd->gd_ctx;

                        gd->gd_cred.gc_proc = RPCSEC_GSS_DATA;
                        gd->gd_seq = 1;
                        gd->gd_win = gr.gr_win;
                        break;
                }
        }

        gss_release_name(&min_stat, &name);
        xdr_free((xdrproc_t) xdr_gss_buffer_desc,
            (char *) &gd->gd_verf);

out:
        /* End context negotiation loop. */
        if (gd->gd_cred.gc_proc != RPCSEC_GSS_DATA) {
                rpc_createerr.cf_stat = RPC_AUTHERROR;
                _rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR, EPERM);
                if (gd->gd_ctx) {
                        gss_delete_sec_context(&min_stat, &gd->gd_ctx,
                                GSS_C_NO_BUFFER);
                }
                mtx_lock(&gd->gd_lock);
                gd->gd_state = RPCSEC_GSS_START;
                wakeup(gd);
                mtx_unlock(&gd->gd_lock);
                return (FALSE);
        }
        
        mtx_lock(&gd->gd_lock);
        gd->gd_state = RPCSEC_GSS_ESTABLISHED;
        wakeup(gd);
        mtx_unlock(&gd->gd_lock);

        return (TRUE);
}

static bool_t
rpc_gss_refresh(AUTH *auth, void *msg)
{
        struct rpc_msg *reply = (struct rpc_msg *) msg;
        rpc_gss_options_ret_t options;
        struct rpc_gss_data *gd;

        gd = AUTH_PRIVATE(auth);
        
        /*
         * If the context is in DESTROYING state, then just return, since
         * there is no point in refreshing the credentials.
         */
        mtx_lock(&gd->gd_lock);
        if (gd->gd_state == RPCSEC_GSS_DESTROYING) {
                mtx_unlock(&gd->gd_lock);
                return (FALSE);
        }
        mtx_unlock(&gd->gd_lock);

        /*
         * If the error was RPCSEC_GSS_CREDPROBLEM of
         * RPCSEC_GSS_CTXPROBLEM we start again from scratch. All
         * other errors are fatal.
         */
        if (reply->rm_reply.rp_stat == MSG_DENIED
            && reply->rm_reply.rp_rjct.rj_stat == AUTH_ERROR
            && (reply->rm_reply.rp_rjct.rj_why == RPCSEC_GSS_CREDPROBLEM
                || reply->rm_reply.rp_rjct.rj_why == RPCSEC_GSS_CTXPROBLEM)) {
                rpc_gss_destroy_context(auth, FALSE);
                memset(&options, 0, sizeof(options));
                return (rpc_gss_init(auth, &options));
        }

        return (FALSE);
}

static void
rpc_gss_destroy_context(AUTH *auth, bool_t send_destroy)
{
        struct rpc_gss_data     *gd;
        struct rpc_pending_request *pr;
        OM_uint32                min_stat;
        struct rpc_callextra     ext;

        rpc_gss_log_debug("in rpc_gss_destroy_context()");
        
        gd = AUTH_PRIVATE(auth);
        
        mtx_lock(&gd->gd_lock);
        /*
         * If the context isn't in ESTABISHED state, someone else is
         * destroying/refreshing - we wait till they are done.
         */
        if (gd->gd_state != RPCSEC_GSS_ESTABLISHED) {
                while (gd->gd_state != RPCSEC_GSS_START
                    && gd->gd_state != RPCSEC_GSS_ESTABLISHED)
                        msleep(gd, &gd->gd_lock, 0, "gssstate", 0);
                mtx_unlock(&gd->gd_lock);
                return;
        }
        gd->gd_state = RPCSEC_GSS_DESTROYING;
        mtx_unlock(&gd->gd_lock);

        if (send_destroy) {
                gd->gd_cred.gc_proc = RPCSEC_GSS_DESTROY;
                bzero(&ext, sizeof(ext));
                ext.rc_auth = auth;
                CLNT_CALL_EXT(gd->gd_clnt, &ext, NULLPROC,
                    (xdrproc_t)xdr_void, NULL,
                    (xdrproc_t)xdr_void, NULL, AUTH_TIMEOUT);
        }

        while ((pr = LIST_FIRST(&gd->gd_reqs)) != NULL) {
                LIST_REMOVE(pr, pr_link);
                mem_free(pr, sizeof(*pr));
        }

        /*
         * Free the context token. Remember that this was
         * allocated by XDR, not GSS-API.
         */
        xdr_free((xdrproc_t) xdr_gss_buffer_desc,
            (char *) &gd->gd_cred.gc_handle);
        gd->gd_cred.gc_handle.length = 0;

        if (gd->gd_ctx != GSS_C_NO_CONTEXT)
                gss_delete_sec_context(&min_stat, &gd->gd_ctx, NULL);

        mtx_lock(&gd->gd_lock);
        gd->gd_state = RPCSEC_GSS_START;
        wakeup(gd);
        mtx_unlock(&gd->gd_lock);
}

static void
rpc_gss_destroy(AUTH *auth)
{
        struct rpc_gss_data     *gd;
        
        rpc_gss_log_debug("in rpc_gss_destroy()");
        
        gd = AUTH_PRIVATE(auth);
        
        if (!refcount_release(&gd->gd_refs))
                return;

        rpc_gss_destroy_context(auth, TRUE);
        
        CLNT_RELEASE(gd->gd_clnt);
        crfree(gd->gd_ucred);
        free(gd->gd_principal, M_RPC);
        if (gd->gd_clntprincipal != NULL)
                free(gd->gd_clntprincipal, M_RPC);
        if (gd->gd_verf.value)
                xdr_free((xdrproc_t) xdr_gss_buffer_desc,
                    (char *) &gd->gd_verf);
        mtx_destroy(&gd->gd_lock);

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

int
rpc_gss_max_data_length(AUTH *auth, int max_tp_unit_len)
{
        struct rpc_gss_data     *gd;
        int                     want_conf;
        OM_uint32               max;
        OM_uint32               maj_stat, min_stat;
        int                     result;

        gd = AUTH_PRIVATE(auth);

        switch (gd->gd_cred.gc_svc) {
        case rpc_gss_svc_none:
                return (max_tp_unit_len);
                break;

        case rpc_gss_svc_default:
        case rpc_gss_svc_integrity:
                want_conf = FALSE;
                break;

        case rpc_gss_svc_privacy:
                want_conf = TRUE;
                break;

        default:
                return (0);
        }

        maj_stat = gss_wrap_size_limit(&min_stat, gd->gd_ctx, want_conf,
            gd->gd_qop, max_tp_unit_len, &max);

        if (maj_stat == GSS_S_COMPLETE) {
                result = (int) max;
                if (result < 0)
                        result = 0;
                return (result);
        } else {
                rpc_gss_log_status("gss_wrap_size_limit", gd->gd_mech,
                    maj_stat, min_stat);
                return (0);
        }
}