/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2016, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lustre/ptlrpc/gss/gss_cli_upcall.c
 *
 * Author: Eric Mei <ericm@clusterfs.com>
 */

#define DEBUG_SUBSYSTEM S_SEC
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/dcache.h>
#include <linux/fs.h>
#include <linux/mutex.h>

#include <obd.h>
#include <obd_class.h>
#include <obd_support.h>
#include <lustre_net.h>
#include <lustre_import.h>
#include <lustre_sec.h>

#include "gss_err.h"
#include "gss_internal.h"
#include "gss_api.h"

/**********************************************
 * gss context init/fini helper               *
 **********************************************/

static
int ctx_init_pack_request(struct obd_import *imp,
			  struct ptlrpc_request *req,
			  int lustre_srv,
			  uid_t uid, gid_t gid,
			  long token_size,
			  char __user *token)
{
	struct lustre_msg       *msg = req->rq_reqbuf;
	struct gss_sec          *gsec;
	struct gss_header       *ghdr;
	struct ptlrpc_user_desc *pud;
	__u32                   *p, size, offset = 2;
	rawobj_t                 obj;

	LASSERT(msg->lm_bufcount <= 4);
	LASSERT(req->rq_cli_ctx);
	LASSERT(req->rq_cli_ctx->cc_sec);

	/* gss hdr */
	ghdr = lustre_msg_buf(msg, 0, sizeof(*ghdr));
	ghdr->gh_version = PTLRPC_GSS_VERSION;
	ghdr->gh_sp = (__u8) imp->imp_sec->ps_part;
	ghdr->gh_flags = 0;
	ghdr->gh_proc = PTLRPC_GSS_PROC_INIT;
	ghdr->gh_seq = 0;
	ghdr->gh_svc = SPTLRPC_SVC_NULL;
	ghdr->gh_handle.len = 0;

	/* fix the user desc */
	if (req->rq_pack_udesc) {
		ghdr->gh_flags |= LUSTRE_GSS_PACK_USER;

		pud = lustre_msg_buf(msg, offset, sizeof(*pud));
		LASSERT(pud);
		pud->pud_uid = pud->pud_fsuid = uid;
		pud->pud_gid = pud->pud_fsgid = gid;
		pud->pud_cap = 0;
		pud->pud_ngroups = 0;
		offset++;
	}

	/* new clients are expected to set KCSUM flag */
	ghdr->gh_flags |= LUSTRE_GSS_PACK_KCSUM;

	/* security payload */
	p = lustre_msg_buf(msg, offset, 0);
	size = msg->lm_buflens[offset];
	LASSERT(p);

	/* 1. lustre svc type */
	LASSERT(size > 4);
	*p++ = cpu_to_le32(lustre_srv);
	size -= 4;

	/* 2. target uuid */
	obj.len = strlen(imp->imp_obd->u.cli.cl_target_uuid.uuid) + 1;
	obj.data = imp->imp_obd->u.cli.cl_target_uuid.uuid;
	if (rawobj_serialize(&obj, &p, &size))
		LBUG();

	/* 3. reverse context handle. actually only needed by root user,
	 *    but we send it anyway. */
	gsec = sec2gsec(req->rq_cli_ctx->cc_sec);
	obj.len = sizeof(gsec->gs_rvs_hdl);
	obj.data = (__u8 *) &gsec->gs_rvs_hdl;
	if (rawobj_serialize(&obj, &p, &size))
		LBUG();

	/* 4. now the token */
	LASSERT(size >= (sizeof(__u32) + token_size));
	*p++ = cpu_to_le32(((__u32) token_size));
	if (copy_from_user(p, token, token_size)) {
		CERROR("can't copy token\n");
		return -EFAULT;
	}
	size -= sizeof(__u32) + cfs_size_round4(token_size);

	req->rq_reqdata_len = lustre_shrink_msg(req->rq_reqbuf, offset,
					     msg->lm_buflens[offset] - size, 0);
	return 0;
}

static
int ctx_init_parse_reply(struct lustre_msg *msg, int swabbed,
                         char __user *outbuf, long outlen)
{
        struct gss_rep_header   *ghdr;
        __u32                    obj_len, round_len;
        __u32                    status, effective = 0;

        if (msg->lm_bufcount != 3) {
                CERROR("unexpected bufcount %u\n", msg->lm_bufcount);
                return -EPROTO;
        }

        ghdr = (struct gss_rep_header *) gss_swab_header(msg, 0, swabbed);
        if (ghdr == NULL) {
                CERROR("unable to extract gss reply header\n");
                return -EPROTO;
        }

        if (ghdr->gh_version != PTLRPC_GSS_VERSION) {
                CERROR("invalid gss version %u\n", ghdr->gh_version);
                return -EPROTO;
        }

        if (outlen < (4 + 2) * 4 + cfs_size_round4(ghdr->gh_handle.len) +
                     cfs_size_round4(msg->lm_buflens[2])) {
                CERROR("output buffer size %ld too small\n", outlen);
                return -EFAULT;
        }

        status = 0;
        effective = 0;

	if (copy_to_user(outbuf, &status, 4))
		return -EFAULT;
	outbuf += 4;
	if (copy_to_user(outbuf, &ghdr->gh_major, 4))
		return -EFAULT;
	outbuf += 4;
	if (copy_to_user(outbuf, &ghdr->gh_minor, 4))
		return -EFAULT;
	outbuf += 4;
	if (copy_to_user(outbuf, &ghdr->gh_seqwin, 4))
		return -EFAULT;
	outbuf += 4;
	effective += 4 * 4;

	/* handle */
	obj_len = ghdr->gh_handle.len;
	round_len = (obj_len + 3) & ~3;
	if (copy_to_user(outbuf, &obj_len, 4))
		return -EFAULT;
	outbuf += 4;
	if (copy_to_user(outbuf, (char *) ghdr->gh_handle.data, round_len))
		return -EFAULT;
	outbuf += round_len;
	effective += 4 + round_len;

	/* out token */
	obj_len = msg->lm_buflens[2];
	round_len = (obj_len + 3) & ~3;
	if (copy_to_user(outbuf, &obj_len, 4))
		return -EFAULT;
	outbuf += 4;
	if (copy_to_user(outbuf, lustre_msg_buf(msg, 2, 0), round_len))
		return -EFAULT;
	outbuf += round_len;
	effective += 4 + round_len;

	return effective;
}

/* XXX move to where lgssd could see */
struct lgssd_ioctl_param {
        int             version;        /* in   */
        int             secid;          /* in   */
	char __user    *uuid;		/* in   */
        int             lustre_svc;     /* in   */
        uid_t           uid;            /* in   */
        gid_t           gid;            /* in   */
        long            send_token_size;/* in   */
	char __user    *send_token;     /* in   */
        long            reply_buf_size; /* in   */
	char __user    *reply_buf;	/* in   */
        long            status;         /* out  */
        long            reply_length;   /* out  */
};

int gss_do_ctx_init_rpc(char __user *buffer, unsigned long count)
{
        struct obd_import        *imp;
        struct ptlrpc_request    *req;
        struct lgssd_ioctl_param  param;
        struct obd_device        *obd;
        char                      obdname[64];
        long                      lsize;
        int                       rc;

        if (count != sizeof(param)) {
                CERROR("ioctl size %lu, expect %lu, please check lgss_keyring "
                       "version\n", count, (unsigned long) sizeof(param));
                RETURN(-EINVAL);
        }
	if (copy_from_user(&param, buffer, sizeof(param))) {
                CERROR("failed copy data from lgssd\n");
                RETURN(-EFAULT);
        }

        if (param.version != GSSD_INTERFACE_VERSION) {
                CERROR("gssd interface version %d (expect %d)\n",
                        param.version, GSSD_INTERFACE_VERSION);
                RETURN(-EINVAL);
        }

        /* take name */
        if (strncpy_from_user(obdname, param.uuid, sizeof(obdname)) <= 0) {
                CERROR("Invalid obdname pointer\n");
                RETURN(-EFAULT);
        }

        obd = class_name2obd(obdname);
        if (!obd) {
                CERROR("no such obd %s\n", obdname);
                RETURN(-EINVAL);
        }

        if (unlikely(!obd->obd_set_up)) {
                CERROR("obd %s not setup\n", obdname);
                RETURN(-EINVAL);
        }

	spin_lock(&obd->obd_dev_lock);
	if (obd->obd_stopping) {
		CERROR("obd %s has stopped\n", obdname);
		spin_unlock(&obd->obd_dev_lock);
		RETURN(-EINVAL);
	}

	if (strcmp(obd->obd_type->typ_name, LUSTRE_MDC_NAME) &&
	    strcmp(obd->obd_type->typ_name, LUSTRE_OSC_NAME) &&
	    strcmp(obd->obd_type->typ_name, LUSTRE_MGC_NAME) &&
	    strcmp(obd->obd_type->typ_name, LUSTRE_LWP_NAME) &&
	    strcmp(obd->obd_type->typ_name, LUSTRE_OSP_NAME)) {
		CERROR("obd %s is not a client device\n", obdname);
		spin_unlock(&obd->obd_dev_lock);
		RETURN(-EINVAL);
	}
	spin_unlock(&obd->obd_dev_lock);

	down_read(&obd->u.cli.cl_sem);
	if (obd->u.cli.cl_import == NULL) {
		CERROR("obd %s: import has gone\n", obd->obd_name);
		up_read(&obd->u.cli.cl_sem);
		RETURN(-EINVAL);
	}
	imp = class_import_get(obd->u.cli.cl_import);
	up_read(&obd->u.cli.cl_sem);

        if (imp->imp_deactive) {
                CERROR("import has been deactivated\n");
                class_import_put(imp);
                RETURN(-EINVAL);
        }

        req = ptlrpc_request_alloc_pack(imp, &RQF_SEC_CTX, LUSTRE_OBD_VERSION,
                                        SEC_CTX_INIT);
        if (req == NULL) {
                param.status = -ENOMEM;
                goto out_copy;
        }

        if (req->rq_cli_ctx->cc_sec->ps_id != param.secid) {
                CWARN("original secid %d, now has changed to %d, "
                      "cancel this negotiation\n", param.secid,
                      req->rq_cli_ctx->cc_sec->ps_id);
                param.status = -EINVAL;
                goto out_copy;
        }

        /* get token */
        rc = ctx_init_pack_request(imp, req,
                                   param.lustre_svc,
                                   param.uid, param.gid,
                                   param.send_token_size,
                                   param.send_token);
        if (rc) {
                param.status = rc;
                goto out_copy;
        }

        ptlrpc_request_set_replen(req);

        rc = ptlrpc_queue_wait(req);
        if (rc) {
                /* If any _real_ denial be made, we expect server return
                 * -EACCES reply or return success but indicate gss error
                 * inside reply messsage. All other errors are treated as
                 * timeout, caller might try the negotiation repeatedly,
                 * leave recovery decisions to general ptlrpc layer.
                 *
                 * FIXME maybe some other error code shouldn't be treated
                 * as timeout. */
                param.status = rc;
                if (rc != -EACCES)
                        param.status = -ETIMEDOUT;
                goto out_copy;
        }

        LASSERT(req->rq_repdata);
        lsize = ctx_init_parse_reply(req->rq_repdata,
                                     ptlrpc_rep_need_swab(req),
                                     param.reply_buf, param.reply_buf_size);
        if (lsize < 0) {
                param.status = (int) lsize;
                goto out_copy;
        }

        param.status = 0;
        param.reply_length = lsize;

out_copy:
	if (copy_to_user(buffer, &param, sizeof(param)))
                rc = -EFAULT;
        else
                rc = 0;

        class_import_put(imp);
        ptlrpc_req_finished(req);
        RETURN(rc);
}

int gss_do_ctx_fini_rpc(struct gss_cli_ctx *gctx)
{
	struct ptlrpc_cli_ctx	*ctx = &gctx->gc_base;
	struct obd_import	*imp = ctx->cc_sec->ps_import;
	struct ptlrpc_request	*req;
	struct ptlrpc_user_desc	*pud;
	int			 rc;
	ENTRY;

	LASSERT(atomic_read(&ctx->cc_refcount) > 0);

	if (cli_ctx_is_error(ctx) || !cli_ctx_is_uptodate(ctx)) {
		CDEBUG(D_SEC, "ctx %p(%u->%s) not uptodate, "
		       "don't send destroy rpc\n", ctx,
		       ctx->cc_vcred.vc_uid, sec2target_str(ctx->cc_sec));
		RETURN(0);
	}

	might_sleep();

	CWARN("%s ctx %p idx %#llx (%u->%s)\n",
	      sec_is_reverse(ctx->cc_sec) ?
	      "server finishing reverse" : "client finishing forward",
	      ctx, gss_handle_to_u64(&gctx->gc_handle),
	      ctx->cc_vcred.vc_uid, sec2target_str(ctx->cc_sec));

        gctx->gc_proc = PTLRPC_GSS_PROC_DESTROY;

        req = ptlrpc_request_alloc(imp, &RQF_SEC_CTX);
        if (req == NULL) {
                CWARN("ctx %p(%u): fail to prepare rpc, destroy locally\n",
                      ctx, ctx->cc_vcred.vc_uid);
                GOTO(out, rc = -ENOMEM);
        }

        rc = ptlrpc_request_bufs_pack(req, LUSTRE_OBD_VERSION, SEC_CTX_FINI,
                                      NULL, ctx);
	if (rc)
		GOTO(out_ref, rc);

        /* fix the user desc */
        if (req->rq_pack_udesc) {
                /* we rely the fact that this request is in AUTH mode,
                 * and user_desc at offset 2. */
                pud = lustre_msg_buf(req->rq_reqbuf, 2, sizeof(*pud));
                LASSERT(pud);
                pud->pud_uid = pud->pud_fsuid = ctx->cc_vcred.vc_uid;
                pud->pud_gid = pud->pud_fsgid = ctx->cc_vcred.vc_gid;
                pud->pud_cap = 0;
                pud->pud_ngroups = 0;
        }

        req->rq_phase = RQ_PHASE_RPC;
        rc = ptl_send_rpc(req, 1);
        if (rc)
                CWARN("ctx %p(%u->%s): rpc error %d, destroy locally\n", ctx,
                      ctx->cc_vcred.vc_uid, sec2target_str(ctx->cc_sec), rc);

out_ref:
        ptlrpc_req_finished(req);
out:
        RETURN(rc);
}

int __init gss_init_cli_upcall(void)
{
        return 0;
}

void gss_exit_cli_upcall(void)
{
}