/*
 *   fs/cifs/smb2pdu.c
 *
 *   Copyright (C) International Business Machines  Corp., 2009, 2013
 *                 Etersoft, 2012
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *              Pavel Shilovsky (pshilovsky@samba.org) 2012
 *
 *   Contains the routines for constructing the SMB2 PDUs themselves
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published
 *   by the Free Software Foundation; either version 2.1 of the License, or
 *   (at your option) any later version.
 *
 *   This library 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 Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

 /* SMB2 PDU handling routines here - except for leftovers (eg session setup) */
 /* Note that there are handle based routines which must be                   */
 /* treated slightly differently for reconnection purposes since we never     */
 /* want to reuse a stale file handle and only the caller knows the file info */

#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/vfs.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/uaccess.h>
#include <linux/uuid.h>
#include <linux/pagemap.h>
#include <linux/xattr.h>
#include "smb2pdu.h"
#include "cifsglob.h"
#include "cifsacl.h"
#include "cifsproto.h"
#include "smb2proto.h"
#include "cifs_unicode.h"
#include "cifs_debug.h"
#include "ntlmssp.h"
#include "smb2status.h"
#include "smb2glob.h"
#include "cifspdu.h"
#include "cifs_spnego.h"
#include "smbdirect.h"
#include "trace.h"
#ifdef CONFIG_CIFS_DFS_UPCALL
#include "dfs_cache.h"
#endif

/*
 *  The following table defines the expected "StructureSize" of SMB2 requests
 *  in order by SMB2 command.  This is similar to "wct" in SMB/CIFS requests.
 *
 *  Note that commands are defined in smb2pdu.h in le16 but the array below is
 *  indexed by command in host byte order.
 */
static const int smb2_req_struct_sizes[NUMBER_OF_SMB2_COMMANDS] = {
        /* SMB2_NEGOTIATE */ 36,
        /* SMB2_SESSION_SETUP */ 25,
        /* SMB2_LOGOFF */ 4,
        /* SMB2_TREE_CONNECT */ 9,
        /* SMB2_TREE_DISCONNECT */ 4,
        /* SMB2_CREATE */ 57,
        /* SMB2_CLOSE */ 24,
        /* SMB2_FLUSH */ 24,
        /* SMB2_READ */ 49,
        /* SMB2_WRITE */ 49,
        /* SMB2_LOCK */ 48,
        /* SMB2_IOCTL */ 57,
        /* SMB2_CANCEL */ 4,
        /* SMB2_ECHO */ 4,
        /* SMB2_QUERY_DIRECTORY */ 33,
        /* SMB2_CHANGE_NOTIFY */ 32,
        /* SMB2_QUERY_INFO */ 41,
        /* SMB2_SET_INFO */ 33,
        /* SMB2_OPLOCK_BREAK */ 24 /* BB this is 36 for LEASE_BREAK variant */
};

int smb3_encryption_required(const struct cifs_tcon *tcon)
{
        if (!tcon)
                return 0;
        if ((tcon->ses->session_flags & SMB2_SESSION_FLAG_ENCRYPT_DATA) ||
            (tcon->share_flags & SHI1005_FLAGS_ENCRYPT_DATA))
                return 1;
        if (tcon->seal &&
            (tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION))
                return 1;
        return 0;
}

static void
smb2_hdr_assemble(struct smb2_sync_hdr *shdr, __le16 smb2_cmd,
                  const struct cifs_tcon *tcon)
{
        shdr->ProtocolId = SMB2_PROTO_NUMBER;
        shdr->StructureSize = cpu_to_le16(64);
        shdr->Command = smb2_cmd;
        if (tcon && tcon->ses && tcon->ses->server) {
                struct TCP_Server_Info *server = tcon->ses->server;

                spin_lock(&server->req_lock);
                /* Request up to 10 credits but don't go over the limit. */
                if (server->credits >= server->max_credits)
                        shdr->CreditRequest = cpu_to_le16(0);
                else
                        shdr->CreditRequest = cpu_to_le16(
                                min_t(int, server->max_credits -
                                                server->credits, 10));
                spin_unlock(&server->req_lock);
        } else {
                shdr->CreditRequest = cpu_to_le16(2);
        }
        shdr->ProcessId = cpu_to_le32((__u16)current->tgid);

        if (!tcon)
                goto out;

        /* GLOBAL_CAP_LARGE_MTU will only be set if dialect > SMB2.02 */
        /* See sections 2.2.4 and 3.2.4.1.5 of MS-SMB2 */
        if ((tcon->ses) && (tcon->ses->server) &&
            (tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU))
                shdr->CreditCharge = cpu_to_le16(1);
        /* else CreditCharge MBZ */

        shdr->TreeId = tcon->tid;
        /* Uid is not converted */
        if (tcon->ses)
                shdr->SessionId = tcon->ses->Suid;

        /*
         * If we would set SMB2_FLAGS_DFS_OPERATIONS on open we also would have
         * to pass the path on the Open SMB prefixed by \\server\share.
         * Not sure when we would need to do the augmented path (if ever) and
         * setting this flag breaks the SMB2 open operation since it is
         * illegal to send an empty path name (without \\server\share prefix)
         * when the DFS flag is set in the SMB open header. We could
         * consider setting the flag on all operations other than open
         * but it is safer to net set it for now.
         */
/*      if (tcon->share_flags & SHI1005_FLAGS_DFS)
                shdr->Flags |= SMB2_FLAGS_DFS_OPERATIONS; */

        if (tcon->ses && tcon->ses->server && tcon->ses->server->sign &&
            !smb3_encryption_required(tcon))
                shdr->Flags |= SMB2_FLAGS_SIGNED;
out:
        return;
}

#ifdef CONFIG_CIFS_DFS_UPCALL
static int __smb2_reconnect(const struct nls_table *nlsc,
                            struct cifs_tcon *tcon)
{
        int rc;
        struct dfs_cache_tgt_list tl;
        struct dfs_cache_tgt_iterator *it = NULL;
        char *tree;
        const char *tcp_host;
        size_t tcp_host_len;
        const char *dfs_host;
        size_t dfs_host_len;

        tree = kzalloc(MAX_TREE_SIZE, GFP_KERNEL);
        if (!tree)
                return -ENOMEM;

        if (tcon->ipc) {
                scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$",
                          tcon->ses->server->hostname);
                rc = SMB2_tcon(0, tcon->ses, tree, tcon, nlsc);
                goto out;
        }

        if (!tcon->dfs_path) {
                rc = SMB2_tcon(0, tcon->ses, tcon->treeName, tcon, nlsc);
                goto out;
        }

        rc = dfs_cache_noreq_find(tcon->dfs_path + 1, NULL, &tl);
        if (rc)
                goto out;

        extract_unc_hostname(tcon->ses->server->hostname, &tcp_host,
                             &tcp_host_len);

        for (it = dfs_cache_get_tgt_iterator(&tl); it;
             it = dfs_cache_get_next_tgt(&tl, it)) {
                const char *tgt = dfs_cache_get_tgt_name(it);

                extract_unc_hostname(tgt, &dfs_host, &dfs_host_len);

                if (dfs_host_len != tcp_host_len
                    || strncasecmp(dfs_host, tcp_host, dfs_host_len) != 0) {
                        cifs_dbg(FYI, "%s: skipping %.*s, doesn't match %.*s",
                                 __func__,
                                 (int)dfs_host_len, dfs_host,
                                 (int)tcp_host_len, tcp_host);
                        continue;
                }

                scnprintf(tree, MAX_TREE_SIZE, "\\%s", tgt);

                rc = SMB2_tcon(0, tcon->ses, tree, tcon, nlsc);
                if (!rc)
                        break;
                if (rc == -EREMOTE)
                        break;
        }

        if (!rc) {
                if (it)
                        rc = dfs_cache_noreq_update_tgthint(tcon->dfs_path + 1,
                                                            it);
                else
                        rc = -ENOENT;
        }
        dfs_cache_free_tgts(&tl);
out:
        kfree(tree);
        return rc;
}
#else
static inline int __smb2_reconnect(const struct nls_table *nlsc,
                                   struct cifs_tcon *tcon)
{
        return SMB2_tcon(0, tcon->ses, tcon->treeName, tcon, nlsc);
}
#endif

static int
smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon)
{
        int rc;
        struct nls_table *nls_codepage;
        struct cifs_ses *ses;
        struct TCP_Server_Info *server;
        int retries;

        /*
         * SMB2s NegProt, SessSetup, Logoff do not have tcon yet so
         * check for tcp and smb session status done differently
         * for those three - in the calling routine.
         */
        if (tcon == NULL)
                return 0;

        if (smb2_command == SMB2_TREE_CONNECT)
                return 0;

        if (tcon->tidStatus == CifsExiting) {
                /*
                 * only tree disconnect, open, and write,
                 * (and ulogoff which does not have tcon)
                 * are allowed as we start force umount.
                 */
                if ((smb2_command != SMB2_WRITE) &&
                   (smb2_command != SMB2_CREATE) &&
                   (smb2_command != SMB2_TREE_DISCONNECT)) {
                        cifs_dbg(FYI, "can not send cmd %d while umounting\n",
                                 smb2_command);
                        return -ENODEV;
                }
        }
        if ((!tcon->ses) || (tcon->ses->status == CifsExiting) ||
            (!tcon->ses->server))
                return -EIO;

        ses = tcon->ses;
        server = ses->server;

        retries = server->nr_targets;

        /*
         * Give demultiplex thread up to 10 seconds to each target available for
         * reconnect -- should be greater than cifs socket timeout which is 7
         * seconds.
         */
        while (server->tcpStatus == CifsNeedReconnect) {
                /*
                 * Return to caller for TREE_DISCONNECT and LOGOFF and CLOSE
                 * here since they are implicitly done when session drops.
                 */
                switch (smb2_command) {
                /*
                 * BB Should we keep oplock break and add flush to exceptions?
                 */
                case SMB2_TREE_DISCONNECT:
                case SMB2_CANCEL:
                case SMB2_CLOSE:
                case SMB2_OPLOCK_BREAK:
                        return -EAGAIN;
                }

                rc = wait_event_interruptible_timeout(server->response_q,
                                                      (server->tcpStatus != CifsNeedReconnect),
                                                      10 * HZ);
                if (rc < 0) {
                        cifs_dbg(FYI, "%s: aborting reconnect due to a received"
                                 " signal by the process\n", __func__);
                        return -ERESTARTSYS;
                }

                /* are we still trying to reconnect? */
                if (server->tcpStatus != CifsNeedReconnect)
                        break;

                if (--retries)
                        continue;

                /*
                 * on "soft" mounts we wait once. Hard mounts keep
                 * retrying until process is killed or server comes
                 * back on-line
                 */
                if (!tcon->retry) {
                        cifs_dbg(FYI, "gave up waiting on reconnect in smb_init\n");
                        return -EHOSTDOWN;
                }
                retries = server->nr_targets;
        }

        if (!tcon->ses->need_reconnect && !tcon->need_reconnect)
                return 0;

        nls_codepage = load_nls_default();

        /*
         * need to prevent multiple threads trying to simultaneously reconnect
         * the same SMB session
         */
        mutex_lock(&tcon->ses->session_mutex);

        /*
         * Recheck after acquire mutex. If another thread is negotiating
         * and the server never sends an answer the socket will be closed
         * and tcpStatus set to reconnect.
         */
        if (server->tcpStatus == CifsNeedReconnect) {
                rc = -EHOSTDOWN;
                mutex_unlock(&tcon->ses->session_mutex);
                goto out;
        }

        rc = cifs_negotiate_protocol(0, tcon->ses);
        if (!rc && tcon->ses->need_reconnect)
                rc = cifs_setup_session(0, tcon->ses, nls_codepage);

        if (rc || !tcon->need_reconnect) {
                mutex_unlock(&tcon->ses->session_mutex);
                goto out;
        }

        cifs_mark_open_files_invalid(tcon);
        if (tcon->use_persistent)
                tcon->need_reopen_files = true;

        rc = __smb2_reconnect(nls_codepage, tcon);
        mutex_unlock(&tcon->ses->session_mutex);

        cifs_dbg(FYI, "reconnect tcon rc = %d\n", rc);
        if (rc) {
                /* If sess reconnected but tcon didn't, something strange ... */
                printk_once(KERN_WARNING "reconnect tcon failed rc = %d\n", rc);
                goto out;
        }

        if (smb2_command != SMB2_INTERNAL_CMD)
                queue_delayed_work(cifsiod_wq, &server->reconnect, 0);

        atomic_inc(&tconInfoReconnectCount);
out:
        /*
         * Check if handle based operation so we know whether we can continue
         * or not without returning to caller to reset file handle.
         */
        /*
         * BB Is flush done by server on drop of tcp session? Should we special
         * case it and skip above?
         */
        switch (smb2_command) {
        case SMB2_FLUSH:
        case SMB2_READ:
        case SMB2_WRITE:
        case SMB2_LOCK:
        case SMB2_IOCTL:
        case SMB2_QUERY_DIRECTORY:
        case SMB2_CHANGE_NOTIFY:
        case SMB2_QUERY_INFO:
        case SMB2_SET_INFO:
                rc = -EAGAIN;
        }
        unload_nls(nls_codepage);
        return rc;
}

static void
fill_small_buf(__le16 smb2_command, struct cifs_tcon *tcon, void *buf,
               unsigned int *total_len)
{
        struct smb2_sync_pdu *spdu = (struct smb2_sync_pdu *)buf;
        /* lookup word count ie StructureSize from table */
        __u16 parmsize = smb2_req_struct_sizes[le16_to_cpu(smb2_command)];

        /*
         * smaller than SMALL_BUFFER_SIZE but bigger than fixed area of
         * largest operations (Create)
         */
        memset(buf, 0, 256);

        smb2_hdr_assemble(&spdu->sync_hdr, smb2_command, tcon);
        spdu->StructureSize2 = cpu_to_le16(parmsize);

        *total_len = parmsize + sizeof(struct smb2_sync_hdr);
}

/*
 * Allocate and return pointer to an SMB request hdr, and set basic
 * SMB information in the SMB header. If the return code is zero, this
 * function must have filled in request_buf pointer.
 */
static int __smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon,
                                  void **request_buf, unsigned int *total_len)
{
        /* BB eventually switch this to SMB2 specific small buf size */
        if (smb2_command == SMB2_SET_INFO)
                *request_buf = cifs_buf_get();
        else
                *request_buf = cifs_small_buf_get();
        if (*request_buf == NULL) {
                /* BB should we add a retry in here if not a writepage? */
                return -ENOMEM;
        }

        fill_small_buf(smb2_command, tcon,
                       (struct smb2_sync_hdr *)(*request_buf),
                       total_len);

        if (tcon != NULL) {
                uint16_t com_code = le16_to_cpu(smb2_command);
                cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_sent[com_code]);
                cifs_stats_inc(&tcon->num_smbs_sent);
        }

        return 0;
}

static int smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon,
                               void **request_buf, unsigned int *total_len)
{
        int rc;

        rc = smb2_reconnect(smb2_command, tcon);
        if (rc)
                return rc;

        return __smb2_plain_req_init(smb2_command, tcon, request_buf,
                                     total_len);
}

static int smb2_ioctl_req_init(u32 opcode, struct cifs_tcon *tcon,
                               void **request_buf, unsigned int *total_len)
{
        /* Skip reconnect only for FSCTL_VALIDATE_NEGOTIATE_INFO IOCTLs */
        if (opcode == FSCTL_VALIDATE_NEGOTIATE_INFO) {
                return __smb2_plain_req_init(SMB2_IOCTL, tcon, request_buf,
                                             total_len);
        }
        return smb2_plain_req_init(SMB2_IOCTL, tcon, request_buf, total_len);
}

/* For explanation of negotiate contexts see MS-SMB2 section 2.2.3.1 */

static void
build_preauth_ctxt(struct smb2_preauth_neg_context *pneg_ctxt)
{
        pneg_ctxt->ContextType = SMB2_PREAUTH_INTEGRITY_CAPABILITIES;
        pneg_ctxt->DataLength = cpu_to_le16(38);
        pneg_ctxt->HashAlgorithmCount = cpu_to_le16(1);
        pneg_ctxt->SaltLength = cpu_to_le16(SMB311_SALT_SIZE);
        get_random_bytes(pneg_ctxt->Salt, SMB311_SALT_SIZE);
        pneg_ctxt->HashAlgorithms = SMB2_PREAUTH_INTEGRITY_SHA512;
}

static void
build_compression_ctxt(struct smb2_compression_capabilities_context *pneg_ctxt)
{
        pneg_ctxt->ContextType = SMB2_COMPRESSION_CAPABILITIES;
        pneg_ctxt->DataLength =
                cpu_to_le16(sizeof(struct smb2_compression_capabilities_context)
                          - sizeof(struct smb2_neg_context));
        pneg_ctxt->CompressionAlgorithmCount = cpu_to_le16(3);
        pneg_ctxt->CompressionAlgorithms[0] = SMB3_COMPRESS_LZ77;
        pneg_ctxt->CompressionAlgorithms[1] = SMB3_COMPRESS_LZ77_HUFF;
        pneg_ctxt->CompressionAlgorithms[2] = SMB3_COMPRESS_LZNT1;
}

static void
build_encrypt_ctxt(struct smb2_encryption_neg_context *pneg_ctxt)
{
        pneg_ctxt->ContextType = SMB2_ENCRYPTION_CAPABILITIES;
        pneg_ctxt->DataLength = cpu_to_le16(6); /* Cipher Count + two ciphers */
        pneg_ctxt->CipherCount = cpu_to_le16(2);
        pneg_ctxt->Ciphers[0] = SMB2_ENCRYPTION_AES128_GCM;
        pneg_ctxt->Ciphers[1] = SMB2_ENCRYPTION_AES128_CCM;
}

static unsigned int
build_netname_ctxt(struct smb2_netname_neg_context *pneg_ctxt, char *hostname)
{
        struct nls_table *cp = load_nls_default();

        pneg_ctxt->ContextType = SMB2_NETNAME_NEGOTIATE_CONTEXT_ID;

        /* copy up to max of first 100 bytes of server name to NetName field */
        pneg_ctxt->DataLength = cpu_to_le16(2 * cifs_strtoUTF16(pneg_ctxt->NetName, hostname, 100, cp));
        /* context size is DataLength + minimal smb2_neg_context */
        return DIV_ROUND_UP(le16_to_cpu(pneg_ctxt->DataLength) +
                        sizeof(struct smb2_neg_context), 8) * 8;
}

static void
build_posix_ctxt(struct smb2_posix_neg_context *pneg_ctxt)
{
        pneg_ctxt->ContextType = SMB2_POSIX_EXTENSIONS_AVAILABLE;
        pneg_ctxt->DataLength = cpu_to_le16(POSIX_CTXT_DATA_LEN);
        /* SMB2_CREATE_TAG_POSIX is "0x93AD25509CB411E7B42383DE968BCD7C" */
        pneg_ctxt->Name[0] = 0x93;
        pneg_ctxt->Name[1] = 0xAD;
        pneg_ctxt->Name[2] = 0x25;
        pneg_ctxt->Name[3] = 0x50;
        pneg_ctxt->Name[4] = 0x9C;
        pneg_ctxt->Name[5] = 0xB4;
        pneg_ctxt->Name[6] = 0x11;
        pneg_ctxt->Name[7] = 0xE7;
        pneg_ctxt->Name[8] = 0xB4;
        pneg_ctxt->Name[9] = 0x23;
        pneg_ctxt->Name[10] = 0x83;
        pneg_ctxt->Name[11] = 0xDE;
        pneg_ctxt->Name[12] = 0x96;
        pneg_ctxt->Name[13] = 0x8B;
        pneg_ctxt->Name[14] = 0xCD;
        pneg_ctxt->Name[15] = 0x7C;
}

static void
assemble_neg_contexts(struct smb2_negotiate_req *req,
                      struct TCP_Server_Info *server, unsigned int *total_len)
{
        char *pneg_ctxt;
        unsigned int ctxt_len;

        if (*total_len > 200) {
                /* In case length corrupted don't want to overrun smb buffer */
                cifs_server_dbg(VFS, "Bad frame length assembling neg contexts\n");
                return;
        }

        /*
         * round up total_len of fixed part of SMB3 negotiate request to 8
         * byte boundary before adding negotiate contexts
         */
        *total_len = roundup(*total_len, 8);

        pneg_ctxt = (*total_len) + (char *)req;
        req->NegotiateContextOffset = cpu_to_le32(*total_len);

        build_preauth_ctxt((struct smb2_preauth_neg_context *)pneg_ctxt);
        ctxt_len = DIV_ROUND_UP(sizeof(struct smb2_preauth_neg_context), 8) * 8;
        *total_len += ctxt_len;
        pneg_ctxt += ctxt_len;

        build_encrypt_ctxt((struct smb2_encryption_neg_context *)pneg_ctxt);
        ctxt_len = DIV_ROUND_UP(sizeof(struct smb2_encryption_neg_context), 8) * 8;
        *total_len += ctxt_len;
        pneg_ctxt += ctxt_len;

        if (server->compress_algorithm) {
                build_compression_ctxt((struct smb2_compression_capabilities_context *)
                                pneg_ctxt);
                ctxt_len = DIV_ROUND_UP(
                        sizeof(struct smb2_compression_capabilities_context),
                                8) * 8;
                *total_len += ctxt_len;
                pneg_ctxt += ctxt_len;
                req->NegotiateContextCount = cpu_to_le16(5);
        } else
                req->NegotiateContextCount = cpu_to_le16(4);

        ctxt_len = build_netname_ctxt((struct smb2_netname_neg_context *)pneg_ctxt,
                                        server->hostname);
        *total_len += ctxt_len;
        pneg_ctxt += ctxt_len;

        build_posix_ctxt((struct smb2_posix_neg_context *)pneg_ctxt);
        *total_len += sizeof(struct smb2_posix_neg_context);
}

static void decode_preauth_context(struct smb2_preauth_neg_context *ctxt)
{
        unsigned int len = le16_to_cpu(ctxt->DataLength);

        /* If invalid preauth context warn but use what we requested, SHA-512 */
        if (len < MIN_PREAUTH_CTXT_DATA_LEN) {
                printk_once(KERN_WARNING "server sent bad preauth context\n");
                return;
        }
        if (le16_to_cpu(ctxt->HashAlgorithmCount) != 1)
                printk_once(KERN_WARNING "illegal SMB3 hash algorithm count\n");
        if (ctxt->HashAlgorithms != SMB2_PREAUTH_INTEGRITY_SHA512)
                printk_once(KERN_WARNING "unknown SMB3 hash algorithm\n");
}

static void decode_compress_ctx(struct TCP_Server_Info *server,
                         struct smb2_compression_capabilities_context *ctxt)
{
        unsigned int len = le16_to_cpu(ctxt->DataLength);

        /* sizeof compress context is a one element compression capbility struct */
        if (len < 10) {
                printk_once(KERN_WARNING "server sent bad compression cntxt\n");
                return;
        }
        if (le16_to_cpu(ctxt->CompressionAlgorithmCount) != 1) {
                printk_once(KERN_WARNING "illegal SMB3 compress algorithm count\n");
                return;
        }
        if (le16_to_cpu(ctxt->CompressionAlgorithms[0]) > 3) {
                printk_once(KERN_WARNING "unknown compression algorithm\n");
                return;
        }
        server->compress_algorithm = ctxt->CompressionAlgorithms[0];
}

static int decode_encrypt_ctx(struct TCP_Server_Info *server,
                              struct smb2_encryption_neg_context *ctxt)
{
        unsigned int len = le16_to_cpu(ctxt->DataLength);

        cifs_dbg(FYI, "decode SMB3.11 encryption neg context of len %d\n", len);
        if (len < MIN_ENCRYPT_CTXT_DATA_LEN) {
                printk_once(KERN_WARNING "server sent bad crypto ctxt len\n");
                return -EINVAL;
        }

        if (le16_to_cpu(ctxt->CipherCount) != 1) {
                printk_once(KERN_WARNING "illegal SMB3.11 cipher count\n");
                return -EINVAL;
        }
        cifs_dbg(FYI, "SMB311 cipher type:%d\n", le16_to_cpu(ctxt->Ciphers[0]));
        if ((ctxt->Ciphers[0] != SMB2_ENCRYPTION_AES128_CCM) &&
            (ctxt->Ciphers[0] != SMB2_ENCRYPTION_AES128_GCM)) {
                printk_once(KERN_WARNING "invalid SMB3.11 cipher returned\n");
                return -EINVAL;
        }
        server->cipher_type = ctxt->Ciphers[0];
        server->capabilities |= SMB2_GLOBAL_CAP_ENCRYPTION;
        return 0;
}

static int smb311_decode_neg_context(struct smb2_negotiate_rsp *rsp,
                                     struct TCP_Server_Info *server,
                                     unsigned int len_of_smb)
{
        struct smb2_neg_context *pctx;
        unsigned int offset = le32_to_cpu(rsp->NegotiateContextOffset);
        unsigned int ctxt_cnt = le16_to_cpu(rsp->NegotiateContextCount);
        unsigned int len_of_ctxts, i;
        int rc = 0;

        cifs_dbg(FYI, "decoding %d negotiate contexts\n", ctxt_cnt);
        if (len_of_smb <= offset) {
                cifs_server_dbg(VFS, "Invalid response: negotiate context offset\n");
                return -EINVAL;
        }

        len_of_ctxts = len_of_smb - offset;

        for (i = 0; i < ctxt_cnt; i++) {
                int clen;
                /* check that offset is not beyond end of SMB */
                if (len_of_ctxts == 0)
                        break;

                if (len_of_ctxts < sizeof(struct smb2_neg_context))
                        break;

                pctx = (struct smb2_neg_context *)(offset + (char *)rsp);
                clen = le16_to_cpu(pctx->DataLength);
                if (clen > len_of_ctxts)
                        break;

                if (pctx->ContextType == SMB2_PREAUTH_INTEGRITY_CAPABILITIES)
                        decode_preauth_context(
                                (struct smb2_preauth_neg_context *)pctx);
                else if (pctx->ContextType == SMB2_ENCRYPTION_CAPABILITIES)
                        rc = decode_encrypt_ctx(server,
                                (struct smb2_encryption_neg_context *)pctx);
                else if (pctx->ContextType == SMB2_COMPRESSION_CAPABILITIES)
                        decode_compress_ctx(server,
                                (struct smb2_compression_capabilities_context *)pctx);
                else if (pctx->ContextType == SMB2_POSIX_EXTENSIONS_AVAILABLE)
                        server->posix_ext_supported = true;
                else
                        cifs_server_dbg(VFS, "unknown negcontext of type %d ignored\n",
                                le16_to_cpu(pctx->ContextType));

                if (rc)
                        break;
                /* offsets must be 8 byte aligned */
                clen = (clen + 7) & ~0x7;
                offset += clen + sizeof(struct smb2_neg_context);
                len_of_ctxts -= clen;
        }
        return rc;
}

static struct create_posix *
create_posix_buf(umode_t mode)
{
        struct create_posix *buf;

        buf = kzalloc(sizeof(struct create_posix),
                        GFP_KERNEL);
        if (!buf)
                return NULL;

        buf->ccontext.DataOffset =
                cpu_to_le16(offsetof(struct create_posix, Mode));
        buf->ccontext.DataLength = cpu_to_le32(4);
        buf->ccontext.NameOffset =
                cpu_to_le16(offsetof(struct create_posix, Name));
        buf->ccontext.NameLength = cpu_to_le16(16);

        /* SMB2_CREATE_TAG_POSIX is "0x93AD25509CB411E7B42383DE968BCD7C" */
        buf->Name[0] = 0x93;
        buf->Name[1] = 0xAD;
        buf->Name[2] = 0x25;
        buf->Name[3] = 0x50;
        buf->Name[4] = 0x9C;
        buf->Name[5] = 0xB4;
        buf->Name[6] = 0x11;
        buf->Name[7] = 0xE7;
        buf->Name[8] = 0xB4;
        buf->Name[9] = 0x23;
        buf->Name[10] = 0x83;
        buf->Name[11] = 0xDE;
        buf->Name[12] = 0x96;
        buf->Name[13] = 0x8B;
        buf->Name[14] = 0xCD;
        buf->Name[15] = 0x7C;
        buf->Mode = cpu_to_le32(mode);
        cifs_dbg(FYI, "mode on posix create 0%o", mode);
        return buf;
}

static int
add_posix_context(struct kvec *iov, unsigned int *num_iovec, umode_t mode)
{
        struct smb2_create_req *req = iov[0].iov_base;
        unsigned int num = *num_iovec;

        iov[num].iov_base = create_posix_buf(mode);
        if (mode == ACL_NO_MODE)
                cifs_dbg(FYI, "illegal mode\n");
        if (iov[num].iov_base == NULL)
                return -ENOMEM;
        iov[num].iov_len = sizeof(struct create_posix);
        if (!req->CreateContextsOffset)
                req->CreateContextsOffset = cpu_to_le32(
                                sizeof(struct smb2_create_req) +
                                iov[num - 1].iov_len);
        le32_add_cpu(&req->CreateContextsLength, sizeof(struct create_posix));
        *num_iovec = num + 1;
        return 0;
}


/*
 *
 *      SMB2 Worker functions follow:
 *
 *      The general structure of the worker functions is:
 *      1) Call smb2_init (assembles SMB2 header)
 *      2) Initialize SMB2 command specific fields in fixed length area of SMB
 *      3) Call smb_sendrcv2 (sends request on socket and waits for response)
 *      4) Decode SMB2 command specific fields in the fixed length area
 *      5) Decode variable length data area (if any for this SMB2 command type)
 *      6) Call free smb buffer
 *      7) return
 *
 */

int
SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
{
        struct smb_rqst rqst;
        struct smb2_negotiate_req *req;
        struct smb2_negotiate_rsp *rsp;
        struct kvec iov[1];
        struct kvec rsp_iov;
        int rc = 0;
        int resp_buftype;
        struct TCP_Server_Info *server = cifs_ses_server(ses);
        int blob_offset, blob_length;
        char *security_blob;
        int flags = CIFS_NEG_OP;
        unsigned int total_len;

        cifs_dbg(FYI, "Negotiate protocol\n");

        if (!server) {
                WARN(1, "%s: server is NULL!\n", __func__);
                return -EIO;
        }

        rc = smb2_plain_req_init(SMB2_NEGOTIATE, NULL, (void **) &req, &total_len);
        if (rc)
                return rc;

        req->sync_hdr.SessionId = 0;

        memset(server->preauth_sha_hash, 0, SMB2_PREAUTH_HASH_SIZE);
        memset(ses->preauth_sha_hash, 0, SMB2_PREAUTH_HASH_SIZE);

        if (strcmp(server->vals->version_string,
                   SMB3ANY_VERSION_STRING) == 0) {
                req->Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
                req->Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
                req->DialectCount = cpu_to_le16(2);
                total_len += 4;
        } else if (strcmp(server->vals->version_string,
                   SMBDEFAULT_VERSION_STRING) == 0) {
                req->Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
                req->Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
                req->Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
                req->Dialects[3] = cpu_to_le16(SMB311_PROT_ID);
                req->DialectCount = cpu_to_le16(4);
                total_len += 8;
        } else {
                /* otherwise send specific dialect */
                req->Dialects[0] = cpu_to_le16(server->vals->protocol_id);
                req->DialectCount = cpu_to_le16(1);
                total_len += 2;
        }

        /* only one of SMB2 signing flags may be set in SMB2 request */
        if (ses->sign)
                req->SecurityMode = cpu_to_le16(SMB2_NEGOTIATE_SIGNING_REQUIRED);
        else if (global_secflags & CIFSSEC_MAY_SIGN)
                req->SecurityMode = cpu_to_le16(SMB2_NEGOTIATE_SIGNING_ENABLED);
        else
                req->SecurityMode = 0;

        req->Capabilities = cpu_to_le32(server->vals->req_capabilities);

        /* ClientGUID must be zero for SMB2.02 dialect */
        if (server->vals->protocol_id == SMB20_PROT_ID)
                memset(req->ClientGUID, 0, SMB2_CLIENT_GUID_SIZE);
        else {
                memcpy(req->ClientGUID, server->client_guid,
                        SMB2_CLIENT_GUID_SIZE);
                if ((server->vals->protocol_id == SMB311_PROT_ID) ||
                    (strcmp(server->vals->version_string,
                     SMBDEFAULT_VERSION_STRING) == 0))
                        assemble_neg_contexts(req, server, &total_len);
        }
        iov[0].iov_base = (char *)req;
        iov[0].iov_len = total_len;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = iov;
        rqst.rq_nvec = 1;

        rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
        cifs_small_buf_release(req);
        rsp = (struct smb2_negotiate_rsp *)rsp_iov.iov_base;
        /*
         * No tcon so can't do
         * cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_fail[SMB2...]);
         */
        if (rc == -EOPNOTSUPP) {
                cifs_server_dbg(VFS, "Dialect not supported by server. Consider "
                        "specifying vers=1.0 or vers=2.0 on mount for accessing"
                        " older servers\n");
                goto neg_exit;
        } else if (rc != 0)
                goto neg_exit;

        if (strcmp(server->vals->version_string,
                   SMB3ANY_VERSION_STRING) == 0) {
                if (rsp->DialectRevision == cpu_to_le16(SMB20_PROT_ID)) {
                        cifs_server_dbg(VFS,
                                "SMB2 dialect returned but not requested\n");
                        return -EIO;
                } else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID)) {
                        cifs_server_dbg(VFS,
                                "SMB2.1 dialect returned but not requested\n");
                        return -EIO;
                }
        } else if (strcmp(server->vals->version_string,
                   SMBDEFAULT_VERSION_STRING) == 0) {
                if (rsp->DialectRevision == cpu_to_le16(SMB20_PROT_ID)) {
                        cifs_server_dbg(VFS,
                                "SMB2 dialect returned but not requested\n");
                        return -EIO;
                } else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID)) {
                        /* ops set to 3.0 by default for default so update */
                        server->ops = &smb21_operations;
                        server->vals = &smb21_values;
                } else if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID)) {
                        server->ops = &smb311_operations;
                        server->vals = &smb311_values;
                }
        } else if (le16_to_cpu(rsp->DialectRevision) !=
                                server->vals->protocol_id) {
                /* if requested single dialect ensure returned dialect matched */
                cifs_server_dbg(VFS, "Illegal 0x%x dialect returned: not requested\n",
                        le16_to_cpu(rsp->DialectRevision));
                return -EIO;
        }

        cifs_dbg(FYI, "mode 0x%x\n", rsp->SecurityMode);

        if (rsp->DialectRevision == cpu_to_le16(SMB20_PROT_ID))
                cifs_dbg(FYI, "negotiated smb2.0 dialect\n");
        else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID))
                cifs_dbg(FYI, "negotiated smb2.1 dialect\n");
        else if (rsp->DialectRevision == cpu_to_le16(SMB30_PROT_ID))
                cifs_dbg(FYI, "negotiated smb3.0 dialect\n");
        else if (rsp->DialectRevision == cpu_to_le16(SMB302_PROT_ID))
                cifs_dbg(FYI, "negotiated smb3.02 dialect\n");
        else if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID))
                cifs_dbg(FYI, "negotiated smb3.1.1 dialect\n");
        else {
                cifs_server_dbg(VFS, "Illegal dialect returned by server 0x%x\n",
                         le16_to_cpu(rsp->DialectRevision));
                rc = -EIO;
                goto neg_exit;
        }
        server->dialect = le16_to_cpu(rsp->DialectRevision);

        /*
         * Keep a copy of the hash after negprot. This hash will be
         * the starting hash value for all sessions made from this
         * server.
         */
        memcpy(server->preauth_sha_hash, ses->preauth_sha_hash,
               SMB2_PREAUTH_HASH_SIZE);

        /* SMB2 only has an extended negflavor */
        server->negflavor = CIFS_NEGFLAVOR_EXTENDED;
        /* set it to the maximum buffer size value we can send with 1 credit */
        server->maxBuf = min_t(unsigned int, le32_to_cpu(rsp->MaxTransactSize),
                               SMB2_MAX_BUFFER_SIZE);
        server->max_read = le32_to_cpu(rsp->MaxReadSize);
        server->max_write = le32_to_cpu(rsp->MaxWriteSize);
        server->sec_mode = le16_to_cpu(rsp->SecurityMode);
        if ((server->sec_mode & SMB2_SEC_MODE_FLAGS_ALL) != server->sec_mode)
                cifs_dbg(FYI, "Server returned unexpected security mode 0x%x\n",
                                server->sec_mode);
        server->capabilities = le32_to_cpu(rsp->Capabilities);
        /* Internal types */
        server->capabilities |= SMB2_NT_FIND | SMB2_LARGE_FILES;

        security_blob = smb2_get_data_area_len(&blob_offset, &blob_length,
                                               (struct smb2_sync_hdr *)rsp);
        /*
         * See MS-SMB2 section 2.2.4: if no blob, client picks default which
         * for us will be
         *      ses->sectype = RawNTLMSSP;
         * but for time being this is our only auth choice so doesn't matter.
         * We just found a server which sets blob length to zero expecting raw.
         */
        if (blob_length == 0) {
                cifs_dbg(FYI, "missing security blob on negprot\n");
                server->sec_ntlmssp = true;
        }

        rc = cifs_enable_signing(server, ses->sign);
        if (rc)
                goto neg_exit;
        if (blob_length) {
                rc = decode_negTokenInit(security_blob, blob_length, server);
                if (rc == 1)
                        rc = 0;
                else if (rc == 0)
                        rc = -EIO;
        }

        if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID)) {
                if (rsp->NegotiateContextCount)
                        rc = smb311_decode_neg_context(rsp, server,

                                                       rsp_iov.iov_len);
                else
                        cifs_server_dbg(VFS, "Missing expected negotiate contexts\n");
        }
neg_exit:
        free_rsp_buf(resp_buftype, rsp);
        return rc;
}

int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
{
        int rc;
        struct validate_negotiate_info_req *pneg_inbuf;
        struct validate_negotiate_info_rsp *pneg_rsp = NULL;
        u32 rsplen;
        u32 inbuflen; /* max of 4 dialects */
        struct TCP_Server_Info *server = tcon->ses->server;

        cifs_dbg(FYI, "validate negotiate\n");

        /* In SMB3.11 preauth integrity supersedes validate negotiate */
        if (server->dialect == SMB311_PROT_ID)
                return 0;

        /*
         * validation ioctl must be signed, so no point sending this if we
         * can not sign it (ie are not known user).  Even if signing is not
         * required (enabled but not negotiated), in those cases we selectively
         * sign just this, the first and only signed request on a connection.
         * Having validation of negotiate info  helps reduce attack vectors.
         */
        if (tcon->ses->session_flags & SMB2_SESSION_FLAG_IS_GUEST)
                return 0; /* validation requires signing */

        if (tcon->ses->user_name == NULL) {
                cifs_dbg(FYI, "Can't validate negotiate: null user mount\n");
                return 0; /* validation requires signing */
        }

        if (tcon->ses->session_flags & SMB2_SESSION_FLAG_IS_NULL)
                cifs_tcon_dbg(VFS, "Unexpected null user (anonymous) auth flag sent by server\n");

        pneg_inbuf = kmalloc(sizeof(*pneg_inbuf), GFP_NOFS);
        if (!pneg_inbuf)
                return -ENOMEM;

        pneg_inbuf->Capabilities =
                        cpu_to_le32(server->vals->req_capabilities);
        memcpy(pneg_inbuf->Guid, server->client_guid,
                                        SMB2_CLIENT_GUID_SIZE);

        if (tcon->ses->sign)
                pneg_inbuf->SecurityMode =
                        cpu_to_le16(SMB2_NEGOTIATE_SIGNING_REQUIRED);
        else if (global_secflags & CIFSSEC_MAY_SIGN)
                pneg_inbuf->SecurityMode =
                        cpu_to_le16(SMB2_NEGOTIATE_SIGNING_ENABLED);
        else
                pneg_inbuf->SecurityMode = 0;


        if (strcmp(server->vals->version_string,
                SMB3ANY_VERSION_STRING) == 0) {
                pneg_inbuf->Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
                pneg_inbuf->Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
                pneg_inbuf->DialectCount = cpu_to_le16(2);
                /* structure is big enough for 3 dialects, sending only 2 */
                inbuflen = sizeof(*pneg_inbuf) -
                                (2 * sizeof(pneg_inbuf->Dialects[0]));
        } else if (strcmp(server->vals->version_string,
                SMBDEFAULT_VERSION_STRING) == 0) {
                pneg_inbuf->Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
                pneg_inbuf->Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
                pneg_inbuf->Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
                pneg_inbuf->Dialects[3] = cpu_to_le16(SMB311_PROT_ID);
                pneg_inbuf->DialectCount = cpu_to_le16(4);
                /* structure is big enough for 3 dialects */
                inbuflen = sizeof(*pneg_inbuf);
        } else {
                /* otherwise specific dialect was requested */
                pneg_inbuf->Dialects[0] =
                        cpu_to_le16(server->vals->protocol_id);
                pneg_inbuf->DialectCount = cpu_to_le16(1);
                /* structure is big enough for 3 dialects, sending only 1 */
                inbuflen = sizeof(*pneg_inbuf) -
                                sizeof(pneg_inbuf->Dialects[0]) * 2;
        }

        rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
                FSCTL_VALIDATE_NEGOTIATE_INFO, true /* is_fsctl */,
                (char *)pneg_inbuf, inbuflen, CIFSMaxBufSize,
                (char **)&pneg_rsp, &rsplen);
        if (rc == -EOPNOTSUPP) {
                /*
                 * Old Windows versions or Netapp SMB server can return
                 * not supported error. Client should accept it.
                 */
                cifs_tcon_dbg(VFS, "Server does not support validate negotiate\n");
                rc = 0;
                goto out_free_inbuf;
        } else if (rc != 0) {
                cifs_tcon_dbg(VFS, "validate protocol negotiate failed: %d\n", rc);
                rc = -EIO;
                goto out_free_inbuf;
        }

        rc = -EIO;
        if (rsplen != sizeof(*pneg_rsp)) {
                cifs_tcon_dbg(VFS, "invalid protocol negotiate response size: %d\n",
                         rsplen);

                /* relax check since Mac returns max bufsize allowed on ioctl */
                if (rsplen > CIFSMaxBufSize || rsplen < sizeof(*pneg_rsp))
                        goto out_free_rsp;
        }

        /* check validate negotiate info response matches what we got earlier */
        if (pneg_rsp->Dialect != cpu_to_le16(server->dialect))
                goto vneg_out;

        if (pneg_rsp->SecurityMode != cpu_to_le16(server->sec_mode))
                goto vneg_out;

        /* do not validate server guid because not saved at negprot time yet */

        if ((le32_to_cpu(pneg_rsp->Capabilities) | SMB2_NT_FIND |
              SMB2_LARGE_FILES) != server->capabilities)
                goto vneg_out;

        /* validate negotiate successful */
        rc = 0;
        cifs_dbg(FYI, "validate negotiate info successful\n");
        goto out_free_rsp;

vneg_out:
        cifs_tcon_dbg(VFS, "protocol revalidation - security settings mismatch\n");
out_free_rsp:
        kfree(pneg_rsp);
out_free_inbuf:
        kfree(pneg_inbuf);
        return rc;
}

enum securityEnum
smb2_select_sectype(struct TCP_Server_Info *server, enum securityEnum requested)
{
        switch (requested) {
        case Kerberos:
        case RawNTLMSSP:
                return requested;
        case NTLMv2:
                return RawNTLMSSP;
        case Unspecified:
                if (server->sec_ntlmssp &&
                        (global_secflags & CIFSSEC_MAY_NTLMSSP))
                        return RawNTLMSSP;
                if ((server->sec_kerberos || server->sec_mskerberos) &&
                        (global_secflags & CIFSSEC_MAY_KRB5))
                        return Kerberos;
                /* Fallthrough */
        default:
                return Unspecified;
        }
}

struct SMB2_sess_data {
        unsigned int xid;
        struct cifs_ses *ses;
        struct nls_table *nls_cp;
        void (*func)(struct SMB2_sess_data *);
        int result;
        u64 previous_session;

        /* we will send the SMB in three pieces:
         * a fixed length beginning part, an optional
         * SPNEGO blob (which can be zero length), and a
         * last part which will include the strings
         * and rest of bcc area. This allows us to avoid
         * a large buffer 17K allocation
         */
        int buf0_type;
        struct kvec iov[2];
};

static int
SMB2_sess_alloc_buffer(struct SMB2_sess_data *sess_data)
{
        int rc;
        struct cifs_ses *ses = sess_data->ses;
        struct smb2_sess_setup_req *req;
        struct TCP_Server_Info *server = cifs_ses_server(ses);
        unsigned int total_len;

        rc = smb2_plain_req_init(SMB2_SESSION_SETUP, NULL, (void **) &req,
                             &total_len);
        if (rc)
                return rc;

        if (sess_data->ses->binding) {
                req->sync_hdr.SessionId = sess_data->ses->Suid;
                req->sync_hdr.Flags |= SMB2_FLAGS_SIGNED;
                req->PreviousSessionId = 0;
                req->Flags = SMB2_SESSION_REQ_FLAG_BINDING;
        } else {
                /* First session, not a reauthenticate */
                req->sync_hdr.SessionId = 0;
                /*
                 * if reconnect, we need to send previous sess id
                 * otherwise it is 0
                 */
                req->PreviousSessionId = sess_data->previous_session;
                req->Flags = 0; /* MBZ */
        }

        /* enough to enable echos and oplocks and one max size write */
        req->sync_hdr.CreditRequest = cpu_to_le16(130);

        /* only one of SMB2 signing flags may be set in SMB2 request */
        if (server->sign)
                req->SecurityMode = SMB2_NEGOTIATE_SIGNING_REQUIRED;
        else if (global_secflags & CIFSSEC_MAY_SIGN) /* one flag unlike MUST_ */
                req->SecurityMode = SMB2_NEGOTIATE_SIGNING_ENABLED;
        else
                req->SecurityMode = 0;

#ifdef CONFIG_CIFS_DFS_UPCALL
        req->Capabilities = cpu_to_le32(SMB2_GLOBAL_CAP_DFS);
#else
        req->Capabilities = 0;
#endif /* DFS_UPCALL */

        req->Channel = 0; /* MBZ */

        sess_data->iov[0].iov_base = (char *)req;
        /* 1 for pad */
        sess_data->iov[0].iov_len = total_len - 1;
        /*
         * This variable will be used to clear the buffer
         * allocated above in case of any error in the calling function.
         */
        sess_data->buf0_type = CIFS_SMALL_BUFFER;

        return 0;
}

static void
SMB2_sess_free_buffer(struct SMB2_sess_data *sess_data)
{
        free_rsp_buf(sess_data->buf0_type, sess_data->iov[0].iov_base);
        sess_data->buf0_type = CIFS_NO_BUFFER;
}

static int
SMB2_sess_sendreceive(struct SMB2_sess_data *sess_data)
{
        int rc;
        struct smb_rqst rqst;
        struct smb2_sess_setup_req *req = sess_data->iov[0].iov_base;
        struct kvec rsp_iov = { NULL, 0 };

        /* Testing shows that buffer offset must be at location of Buffer[0] */
        req->SecurityBufferOffset =
                cpu_to_le16(sizeof(struct smb2_sess_setup_req) - 1 /* pad */);
        req->SecurityBufferLength = cpu_to_le16(sess_data->iov[1].iov_len);

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = sess_data->iov;
        rqst.rq_nvec = 2;

        /* BB add code to build os and lm fields */
        rc = cifs_send_recv(sess_data->xid, sess_data->ses,
                            &rqst,
                            &sess_data->buf0_type,
                            CIFS_LOG_ERROR | CIFS_NEG_OP, &rsp_iov);
        cifs_small_buf_release(sess_data->iov[0].iov_base);
        memcpy(&sess_data->iov[0], &rsp_iov, sizeof(struct kvec));

        return rc;
}

static int
SMB2_sess_establish_session(struct SMB2_sess_data *sess_data)
{
        int rc = 0;
        struct cifs_ses *ses = sess_data->ses;
        struct TCP_Server_Info *server = cifs_ses_server(ses);

        mutex_lock(&server->srv_mutex);
        if (server->ops->generate_signingkey) {
                rc = server->ops->generate_signingkey(ses);
                if (rc) {
                        cifs_dbg(FYI,
                                "SMB3 session key generation failed\n");
                        mutex_unlock(&server->srv_mutex);
                        return rc;
                }
        }
        if (!server->session_estab) {
                server->sequence_number = 0x2;
                server->session_estab = true;
        }
        mutex_unlock(&server->srv_mutex);

        cifs_dbg(FYI, "SMB2/3 session established successfully\n");
        /* keep existing ses state if binding */
        if (!ses->binding) {
                spin_lock(&GlobalMid_Lock);
                ses->status = CifsGood;
                ses->need_reconnect = false;
                spin_unlock(&GlobalMid_Lock);
        }

        return rc;
}

#ifdef CONFIG_CIFS_UPCALL
static void
SMB2_auth_kerberos(struct SMB2_sess_data *sess_data)
{
        int rc;
        struct cifs_ses *ses = sess_data->ses;
        struct cifs_spnego_msg *msg;
        struct key *spnego_key = NULL;
        struct smb2_sess_setup_rsp *rsp = NULL;

        rc = SMB2_sess_alloc_buffer(sess_data);
        if (rc)
                goto out;

        spnego_key = cifs_get_spnego_key(ses);
        if (IS_ERR(spnego_key)) {
                rc = PTR_ERR(spnego_key);
                spnego_key = NULL;
                goto out;
        }

        msg = spnego_key->payload.data[0];
        /*
         * check version field to make sure that cifs.upcall is
         * sending us a response in an expected form
         */
        if (msg->version != CIFS_SPNEGO_UPCALL_VERSION) {
                cifs_dbg(VFS,
                          "bad cifs.upcall version. Expected %d got %d",
                          CIFS_SPNEGO_UPCALL_VERSION, msg->version);
                rc = -EKEYREJECTED;
                goto out_put_spnego_key;
        }

        /* keep session key if binding */
        if (!ses->binding) {
                ses->auth_key.response = kmemdup(msg->data, msg->sesskey_len,
                                                 GFP_KERNEL);
                if (!ses->auth_key.response) {
                        cifs_dbg(VFS,
                                 "Kerberos can't allocate (%u bytes) memory",
                                 msg->sesskey_len);
                        rc = -ENOMEM;
                        goto out_put_spnego_key;
                }
                ses->auth_key.len = msg->sesskey_len;
        }

        sess_data->iov[1].iov_base = msg->data + msg->sesskey_len;
        sess_data->iov[1].iov_len = msg->secblob_len;

        rc = SMB2_sess_sendreceive(sess_data);
        if (rc)
                goto out_put_spnego_key;

        rsp = (struct smb2_sess_setup_rsp *)sess_data->iov[0].iov_base;
        /* keep session id and flags if binding */
        if (!ses->binding) {
                ses->Suid = rsp->sync_hdr.SessionId;
                ses->session_flags = le16_to_cpu(rsp->SessionFlags);
        }

        rc = SMB2_sess_establish_session(sess_data);
out_put_spnego_key:
        key_invalidate(spnego_key);
        key_put(spnego_key);
out:
        sess_data->result = rc;
        sess_data->func = NULL;
        SMB2_sess_free_buffer(sess_data);
}
#else
static void
SMB2_auth_kerberos(struct SMB2_sess_data *sess_data)
{
        cifs_dbg(VFS, "Kerberos negotiated but upcall support disabled!\n");
        sess_data->result = -EOPNOTSUPP;
        sess_data->func = NULL;
}
#endif

static void
SMB2_sess_auth_rawntlmssp_authenticate(struct SMB2_sess_data *sess_data);

static void
SMB2_sess_auth_rawntlmssp_negotiate(struct SMB2_sess_data *sess_data)
{
        int rc;
        struct cifs_ses *ses = sess_data->ses;
        struct smb2_sess_setup_rsp *rsp = NULL;
        char *ntlmssp_blob = NULL;
        bool use_spnego = false; /* else use raw ntlmssp */
        u16 blob_length = 0;

        /*
         * If memory allocation is successful, caller of this function
         * frees it.
         */
        ses->ntlmssp = kmalloc(sizeof(struct ntlmssp_auth), GFP_KERNEL);
        if (!ses->ntlmssp) {
                rc = -ENOMEM;
                goto out_err;
        }
        ses->ntlmssp->sesskey_per_smbsess = true;

        rc = SMB2_sess_alloc_buffer(sess_data);
        if (rc)
                goto out_err;

        ntlmssp_blob = kmalloc(sizeof(struct _NEGOTIATE_MESSAGE),
                               GFP_KERNEL);
        if (ntlmssp_blob == NULL) {
                rc = -ENOMEM;
                goto out;
        }

        build_ntlmssp_negotiate_blob(ntlmssp_blob, ses);
        if (use_spnego) {
                /* BB eventually need to add this */
                cifs_dbg(VFS, "spnego not supported for SMB2 yet\n");
                rc = -EOPNOTSUPP;
                goto out;
        } else {
                blob_length = sizeof(struct _NEGOTIATE_MESSAGE);
                /* with raw NTLMSSP we don't encapsulate in SPNEGO */
        }
        sess_data->iov[1].iov_base = ntlmssp_blob;
        sess_data->iov[1].iov_len = blob_length;

        rc = SMB2_sess_sendreceive(sess_data);
        rsp = (struct smb2_sess_setup_rsp *)sess_data->iov[0].iov_base;

        /* If true, rc here is expected and not an error */
        if (sess_data->buf0_type != CIFS_NO_BUFFER &&
                rsp->sync_hdr.Status == STATUS_MORE_PROCESSING_REQUIRED)
                rc = 0;

        if (rc)
                goto out;

        if (offsetof(struct smb2_sess_setup_rsp, Buffer) !=
                        le16_to_cpu(rsp->SecurityBufferOffset)) {
                cifs_dbg(VFS, "Invalid security buffer offset %d\n",
                        le16_to_cpu(rsp->SecurityBufferOffset));
                rc = -EIO;
                goto out;
        }
        rc = decode_ntlmssp_challenge(rsp->Buffer,
                        le16_to_cpu(rsp->SecurityBufferLength), ses);
        if (rc)
                goto out;

        cifs_dbg(FYI, "rawntlmssp session setup challenge phase\n");

        /* keep existing ses id and flags if binding */
        if (!ses->binding) {
                ses->Suid = rsp->sync_hdr.SessionId;
                ses->session_flags = le16_to_cpu(rsp->SessionFlags);
        }

out:
        kfree(ntlmssp_blob);
        SMB2_sess_free_buffer(sess_data);
        if (!rc) {
                sess_data->result = 0;
                sess_data->func = SMB2_sess_auth_rawntlmssp_authenticate;
                return;
        }
out_err:
        kfree(ses->ntlmssp);
        ses->ntlmssp = NULL;
        sess_data->result = rc;
        sess_data->func = NULL;
}

static void
SMB2_sess_auth_rawntlmssp_authenticate(struct SMB2_sess_data *sess_data)
{
        int rc;
        struct cifs_ses *ses = sess_data->ses;
        struct smb2_sess_setup_req *req;
        struct smb2_sess_setup_rsp *rsp = NULL;
        unsigned char *ntlmssp_blob = NULL;
        bool use_spnego = false; /* else use raw ntlmssp */
        u16 blob_length = 0;

        rc = SMB2_sess_alloc_buffer(sess_data);
        if (rc)
                goto out;

        req = (struct smb2_sess_setup_req *) sess_data->iov[0].iov_base;
        req->sync_hdr.SessionId = ses->Suid;

        rc = build_ntlmssp_auth_blob(&ntlmssp_blob, &blob_length, ses,
                                        sess_data->nls_cp);
        if (rc) {
                cifs_dbg(FYI, "build_ntlmssp_auth_blob failed %d\n", rc);
                goto out;
        }

        if (use_spnego) {
                /* BB eventually need to add this */
                cifs_dbg(VFS, "spnego not supported for SMB2 yet\n");
                rc = -EOPNOTSUPP;
                goto out;
        }
        sess_data->iov[1].iov_base = ntlmssp_blob;
        sess_data->iov[1].iov_len = blob_length;

        rc = SMB2_sess_sendreceive(sess_data);
        if (rc)
                goto out;

        rsp = (struct smb2_sess_setup_rsp *)sess_data->iov[0].iov_base;

        /* keep existing ses id and flags if binding */
        if (!ses->binding) {
                ses->Suid = rsp->sync_hdr.SessionId;
                ses->session_flags = le16_to_cpu(rsp->SessionFlags);
        }

        rc = SMB2_sess_establish_session(sess_data);
out:
        kfree(ntlmssp_blob);
        SMB2_sess_free_buffer(sess_data);
        kfree(ses->ntlmssp);
        ses->ntlmssp = NULL;
        sess_data->result = rc;
        sess_data->func = NULL;
}

static int
SMB2_select_sec(struct cifs_ses *ses, struct SMB2_sess_data *sess_data)
{
        int type;

        type = smb2_select_sectype(cifs_ses_server(ses), ses->sectype);
        cifs_dbg(FYI, "sess setup type %d\n", type);
        if (type == Unspecified) {
                cifs_dbg(VFS,
                        "Unable to select appropriate authentication method!");
                return -EINVAL;
        }

        switch (type) {
        case Kerberos:
                sess_data->func = SMB2_auth_kerberos;
                break;
        case RawNTLMSSP:
                sess_data->func = SMB2_sess_auth_rawntlmssp_negotiate;
                break;
        default:
                cifs_dbg(VFS, "secType %d not supported!\n", type);
                return -EOPNOTSUPP;
        }

        return 0;
}

int
SMB2_sess_setup(const unsigned int xid, struct cifs_ses *ses,
                const struct nls_table *nls_cp)
{
        int rc = 0;
        struct TCP_Server_Info *server = cifs_ses_server(ses);
        struct SMB2_sess_data *sess_data;

        cifs_dbg(FYI, "Session Setup\n");

        if (!server) {
                WARN(1, "%s: server is NULL!\n", __func__);
                return -EIO;
        }

        sess_data = kzalloc(sizeof(struct SMB2_sess_data), GFP_KERNEL);
        if (!sess_data)
                return -ENOMEM;

        rc = SMB2_select_sec(ses, sess_data);
        if (rc)
                goto out;
        sess_data->xid = xid;
        sess_data->ses = ses;
        sess_data->buf0_type = CIFS_NO_BUFFER;
        sess_data->nls_cp = (struct nls_table *) nls_cp;
        sess_data->previous_session = ses->Suid;

        /*
         * Initialize the session hash with the server one.
         */
        memcpy(ses->preauth_sha_hash, server->preauth_sha_hash,
               SMB2_PREAUTH_HASH_SIZE);

        while (sess_data->func)
                sess_data->func(sess_data);

        if ((ses->session_flags & SMB2_SESSION_FLAG_IS_GUEST) && (ses->sign))
                cifs_server_dbg(VFS, "signing requested but authenticated as guest\n");
        rc = sess_data->result;
out:
        kfree(sess_data);
        return rc;
}

int
SMB2_logoff(const unsigned int xid, struct cifs_ses *ses)
{
        struct smb_rqst rqst;
        struct smb2_logoff_req *req; /* response is also trivial struct */
        int rc = 0;
        struct TCP_Server_Info *server;
        int flags = 0;
        unsigned int total_len;
        struct kvec iov[1];
        struct kvec rsp_iov;
        int resp_buf_type;

        cifs_dbg(FYI, "disconnect session %p\n", ses);

        if (ses && (ses->server))
                server = ses->server;
        else
                return -EIO;

        /* no need to send SMB logoff if uid already closed due to reconnect */
        if (ses->need_reconnect)
                goto smb2_session_already_dead;

        rc = smb2_plain_req_init(SMB2_LOGOFF, NULL, (void **) &req, &total_len);
        if (rc)
                return rc;

         /* since no tcon, smb2_init can not do this, so do here */
        req->sync_hdr.SessionId = ses->Suid;

        if (ses->session_flags & SMB2_SESSION_FLAG_ENCRYPT_DATA)
                flags |= CIFS_TRANSFORM_REQ;
        else if (server->sign)
                req->sync_hdr.Flags |= SMB2_FLAGS_SIGNED;

        flags |= CIFS_NO_RSP_BUF;

        iov[0].iov_base = (char *)req;
        iov[0].iov_len = total_len;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = iov;
        rqst.rq_nvec = 1;

        rc = cifs_send_recv(xid, ses, &rqst, &resp_buf_type, flags, &rsp_iov);
        cifs_small_buf_release(req);
        /*
         * No tcon so can't do
         * cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_fail[SMB2...]);
         */

smb2_session_already_dead:
        return rc;
}

static inline void cifs_stats_fail_inc(struct cifs_tcon *tcon, uint16_t code)
{
        cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_failed[code]);
}

#define MAX_SHARENAME_LENGTH (255 /* server */ + 80 /* share */ + 1 /* NULL */)

/* These are similar values to what Windows uses */
static inline void init_copy_chunk_defaults(struct cifs_tcon *tcon)
{
        tcon->max_chunks = 256;
        tcon->max_bytes_chunk = 1048576;
        tcon->max_bytes_copy = 16777216;
}

int
SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
          struct cifs_tcon *tcon, const struct nls_table *cp)
{
        struct smb_rqst rqst;
        struct smb2_tree_connect_req *req;
        struct smb2_tree_connect_rsp *rsp = NULL;
        struct kvec iov[2];
        struct kvec rsp_iov = { NULL, 0 };
        int rc = 0;
        int resp_buftype;
        int unc_path_len;
        __le16 *unc_path = NULL;
        int flags = 0;
        unsigned int total_len;
        struct TCP_Server_Info *server = ses->server;

        cifs_dbg(FYI, "TCON\n");

        if (!server || !tree)
                return -EIO;

        unc_path = kmalloc(MAX_SHARENAME_LENGTH * 2, GFP_KERNEL);
        if (unc_path == NULL)
                return -ENOMEM;

        unc_path_len = cifs_strtoUTF16(unc_path, tree, strlen(tree), cp) + 1;
        unc_path_len *= 2;
        if (unc_path_len < 2) {
                kfree(unc_path);
                return -EINVAL;
        }

        /* SMB2 TREE_CONNECT request must be called with TreeId == 0 */
        tcon->tid = 0;
        atomic_set(&tcon->num_remote_opens, 0);
        rc = smb2_plain_req_init(SMB2_TREE_CONNECT, tcon, (void **) &req,
                             &total_len);
        if (rc) {
                kfree(unc_path);
                return rc;
        }

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        iov[0].iov_base = (char *)req;
        /* 1 for pad */
        iov[0].iov_len = total_len - 1;

        /* Testing shows that buffer offset must be at location of Buffer[0] */
        req->PathOffset = cpu_to_le16(sizeof(struct smb2_tree_connect_req)
                        - 1 /* pad */);
        req->PathLength = cpu_to_le16(unc_path_len - 2);
        iov[1].iov_base = unc_path;
        iov[1].iov_len = unc_path_len;

        /*
         * 3.11 tcon req must be signed if not encrypted. See MS-SMB2 3.2.4.1.1
         * unless it is guest or anonymous user. See MS-SMB2 3.2.5.3.1
         * (Samba servers don't always set the flag so also check if null user)
         */
        if ((server->dialect == SMB311_PROT_ID) &&
            !smb3_encryption_required(tcon) &&
            !(ses->session_flags &
                    (SMB2_SESSION_FLAG_IS_GUEST|SMB2_SESSION_FLAG_IS_NULL)) &&
            ((ses->user_name != NULL) || (ses->sectype == Kerberos)))
                req->sync_hdr.Flags |= SMB2_FLAGS_SIGNED;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = iov;
        rqst.rq_nvec = 2;

        /* Need 64 for max size write so ask for more in case not there yet */
        req->sync_hdr.CreditRequest = cpu_to_le16(64);

        rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
        cifs_small_buf_release(req);
        rsp = (struct smb2_tree_connect_rsp *)rsp_iov.iov_base;
        trace_smb3_tcon(xid, tcon->tid, ses->Suid, tree, rc);
        if (rc != 0) {
                if (tcon) {
                        cifs_stats_fail_inc(tcon, SMB2_TREE_CONNECT_HE);
                        tcon->need_reconnect = true;
                }
                goto tcon_error_exit;
        }

        switch (rsp->ShareType) {
        case SMB2_SHARE_TYPE_DISK:
                cifs_dbg(FYI, "connection to disk share\n");
                break;
        case SMB2_SHARE_TYPE_PIPE:
                tcon->pipe = true;
                cifs_dbg(FYI, "connection to pipe share\n");
                break;
        case SMB2_SHARE_TYPE_PRINT:
                tcon->print = true;
                cifs_dbg(FYI, "connection to printer\n");
                break;
        default:
                cifs_server_dbg(VFS, "unknown share type %d\n", rsp->ShareType);
                rc = -EOPNOTSUPP;
                goto tcon_error_exit;
        }

        tcon->share_flags = le32_to_cpu(rsp->ShareFlags);
        tcon->capabilities = rsp->Capabilities; /* we keep caps little endian */
        tcon->maximal_access = le32_to_cpu(rsp->MaximalAccess);
        tcon->tidStatus = CifsGood;
        tcon->need_reconnect = false;
        tcon->tid = rsp->sync_hdr.TreeId;
        strlcpy(tcon->treeName, tree, sizeof(tcon->treeName));

        if ((rsp->Capabilities & SMB2_SHARE_CAP_DFS) &&
            ((tcon->share_flags & SHI1005_FLAGS_DFS) == 0))
                cifs_tcon_dbg(VFS, "DFS capability contradicts DFS flag\n");

        if (tcon->seal &&
            !(server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION))
                cifs_tcon_dbg(VFS, "Encryption is requested but not supported\n");

        init_copy_chunk_defaults(tcon);
        if (server->ops->validate_negotiate)
                rc = server->ops->validate_negotiate(xid, tcon);
tcon_exit:

        free_rsp_buf(resp_buftype, rsp);
        kfree(unc_path);
        return rc;

tcon_error_exit:
        if (rsp && rsp->sync_hdr.Status == STATUS_BAD_NETWORK_NAME) {
                cifs_tcon_dbg(VFS, "BAD_NETWORK_NAME: %s\n", tree);
        }
        goto tcon_exit;
}

int
SMB2_tdis(const unsigned int xid, struct cifs_tcon *tcon)
{
        struct smb_rqst rqst;
        struct smb2_tree_disconnect_req *req; /* response is trivial */
        int rc = 0;
        struct cifs_ses *ses = tcon->ses;
        int flags = 0;
        unsigned int total_len;
        struct kvec iov[1];
        struct kvec rsp_iov;
        int resp_buf_type;

        cifs_dbg(FYI, "Tree Disconnect\n");

        if (!ses || !(ses->server))
                return -EIO;

        if ((tcon->need_reconnect) || (tcon->ses->need_reconnect))
                return 0;

        close_shroot_lease(&tcon->crfid);

        rc = smb2_plain_req_init(SMB2_TREE_DISCONNECT, tcon, (void **) &req,
                             &total_len);
        if (rc)
                return rc;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        flags |= CIFS_NO_RSP_BUF;

        iov[0].iov_base = (char *)req;
        iov[0].iov_len = total_len;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = iov;
        rqst.rq_nvec = 1;

        rc = cifs_send_recv(xid, ses, &rqst, &resp_buf_type, flags, &rsp_iov);
        cifs_small_buf_release(req);
        if (rc)
                cifs_stats_fail_inc(tcon, SMB2_TREE_DISCONNECT_HE);

        return rc;
}


static struct create_durable *
create_durable_buf(void)
{
        struct create_durable *buf;

        buf = kzalloc(sizeof(struct create_durable), GFP_KERNEL);
        if (!buf)
                return NULL;

        buf->ccontext.DataOffset = cpu_to_le16(offsetof
                                        (struct create_durable, Data));
        buf->ccontext.DataLength = cpu_to_le32(16);
        buf->ccontext.NameOffset = cpu_to_le16(offsetof
                                (struct create_durable, Name));
        buf->ccontext.NameLength = cpu_to_le16(4);
        /* SMB2_CREATE_DURABLE_HANDLE_REQUEST is "DHnQ" */
        buf->Name[0] = 'D';
        buf->Name[1] = 'H';
        buf->Name[2] = 'n';
        buf->Name[3] = 'Q';
        return buf;
}

static struct create_durable *
create_reconnect_durable_buf(struct cifs_fid *fid)
{
        struct create_durable *buf;

        buf = kzalloc(sizeof(struct create_durable), GFP_KERNEL);
        if (!buf)
                return NULL;

        buf->ccontext.DataOffset = cpu_to_le16(offsetof
                                        (struct create_durable, Data));
        buf->ccontext.DataLength = cpu_to_le32(16);
        buf->ccontext.NameOffset = cpu_to_le16(offsetof
                                (struct create_durable, Name));
        buf->ccontext.NameLength = cpu_to_le16(4);
        buf->Data.Fid.PersistentFileId = fid->persistent_fid;
        buf->Data.Fid.VolatileFileId = fid->volatile_fid;
        /* SMB2_CREATE_DURABLE_HANDLE_RECONNECT is "DHnC" */
        buf->Name[0] = 'D';
        buf->Name[1] = 'H';
        buf->Name[2] = 'n';
        buf->Name[3] = 'C';
        return buf;
}

static void
parse_query_id_ctxt(struct create_context *cc, struct smb2_file_all_info *buf)
{
        struct create_on_disk_id *pdisk_id = (struct create_on_disk_id *)cc;

        cifs_dbg(FYI, "parse query id context 0x%llx 0x%llx\n",
                pdisk_id->DiskFileId, pdisk_id->VolumeId);
        buf->IndexNumber = pdisk_id->DiskFileId;
}

void
smb2_parse_contexts(struct TCP_Server_Info *server,
                       struct smb2_create_rsp *rsp,
                       unsigned int *epoch, char *lease_key, __u8 *oplock,
                       struct smb2_file_all_info *buf)
{
        char *data_offset;
        struct create_context *cc;
        unsigned int next;
        unsigned int remaining;
        char *name;

        *oplock = 0;
        data_offset = (char *)rsp + le32_to_cpu(rsp->CreateContextsOffset);
        remaining = le32_to_cpu(rsp->CreateContextsLength);
        cc = (struct create_context *)data_offset;

        /* Initialize inode number to 0 in case no valid data in qfid context */
        if (buf)
                buf->IndexNumber = 0;

        while (remaining >= sizeof(struct create_context)) {
                name = le16_to_cpu(cc->NameOffset) + (char *)cc;
                if (le16_to_cpu(cc->NameLength) == 4 &&
                    strncmp(name, SMB2_CREATE_REQUEST_LEASE, 4) == 0)
                        *oplock = server->ops->parse_lease_buf(cc, epoch,
                                                           lease_key);
                else if (buf && (le16_to_cpu(cc->NameLength) == 4) &&
                    strncmp(name, SMB2_CREATE_QUERY_ON_DISK_ID, 4) == 0)
                        parse_query_id_ctxt(cc, buf);

                next = le32_to_cpu(cc->Next);
                if (!next)
                        break;
                remaining -= next;
                cc = (struct create_context *)((char *)cc + next);
        }

        if (rsp->OplockLevel != SMB2_OPLOCK_LEVEL_LEASE)
                *oplock = rsp->OplockLevel;

        return;
}

static int
add_lease_context(struct TCP_Server_Info *server, struct kvec *iov,
                  unsigned int *num_iovec, u8 *lease_key, __u8 *oplock)
{
        struct smb2_create_req *req = iov[0].iov_base;
        unsigned int num = *num_iovec;

        iov[num].iov_base = server->ops->create_lease_buf(lease_key, *oplock);
        if (iov[num].iov_base == NULL)
                return -ENOMEM;
        iov[num].iov_len = server->vals->create_lease_size;
        req->RequestedOplockLevel = SMB2_OPLOCK_LEVEL_LEASE;
        if (!req->CreateContextsOffset)
                req->CreateContextsOffset = cpu_to_le32(
                                sizeof(struct smb2_create_req) +
                                iov[num - 1].iov_len);
        le32_add_cpu(&req->CreateContextsLength,
                     server->vals->create_lease_size);
        *num_iovec = num + 1;
        return 0;
}

static struct create_durable_v2 *
create_durable_v2_buf(struct cifs_open_parms *oparms)
{
        struct cifs_fid *pfid = oparms->fid;
        struct create_durable_v2 *buf;

        buf = kzalloc(sizeof(struct create_durable_v2), GFP_KERNEL);
        if (!buf)
                return NULL;

        buf->ccontext.DataOffset = cpu_to_le16(offsetof
                                        (struct create_durable_v2, dcontext));
        buf->ccontext.DataLength = cpu_to_le32(sizeof(struct durable_context_v2));
        buf->ccontext.NameOffset = cpu_to_le16(offsetof
                                (struct create_durable_v2, Name));
        buf->ccontext.NameLength = cpu_to_le16(4);

        /*
         * NB: Handle timeout defaults to 0, which allows server to choose
         * (most servers default to 120 seconds) and most clients default to 0.
         * This can be overridden at mount ("handletimeout=") if the user wants
         * a different persistent (or resilient) handle timeout for all opens
         * opens on a particular SMB3 mount.
         */
        buf->dcontext.Timeout = cpu_to_le32(oparms->tcon->handle_timeout);
        buf->dcontext.Flags = cpu_to_le32(SMB2_DHANDLE_FLAG_PERSISTENT);
        generate_random_uuid(buf->dcontext.CreateGuid);
        memcpy(pfid->create_guid, buf->dcontext.CreateGuid, 16);

        /* SMB2_CREATE_DURABLE_HANDLE_REQUEST is "DH2Q" */
        buf->Name[0] = 'D';
        buf->Name[1] = 'H';
        buf->Name[2] = '2';
        buf->Name[3] = 'Q';
        return buf;
}

static struct create_durable_handle_reconnect_v2 *
create_reconnect_durable_v2_buf(struct cifs_fid *fid)
{
        struct create_durable_handle_reconnect_v2 *buf;

        buf = kzalloc(sizeof(struct create_durable_handle_reconnect_v2),
                        GFP_KERNEL);
        if (!buf)
                return NULL;

        buf->ccontext.DataOffset =
                cpu_to_le16(offsetof(struct create_durable_handle_reconnect_v2,
                                     dcontext));
        buf->ccontext.DataLength =
                cpu_to_le32(sizeof(struct durable_reconnect_context_v2));
        buf->ccontext.NameOffset =
                cpu_to_le16(offsetof(struct create_durable_handle_reconnect_v2,
                            Name));
        buf->ccontext.NameLength = cpu_to_le16(4);

        buf->dcontext.Fid.PersistentFileId = fid->persistent_fid;
        buf->dcontext.Fid.VolatileFileId = fid->volatile_fid;
        buf->dcontext.Flags = cpu_to_le32(SMB2_DHANDLE_FLAG_PERSISTENT);
        memcpy(buf->dcontext.CreateGuid, fid->create_guid, 16);

        /* SMB2_CREATE_DURABLE_HANDLE_RECONNECT_V2 is "DH2C" */
        buf->Name[0] = 'D';
        buf->Name[1] = 'H';
        buf->Name[2] = '2';
        buf->Name[3] = 'C';
        return buf;
}

static int
add_durable_v2_context(struct kvec *iov, unsigned int *num_iovec,
                    struct cifs_open_parms *oparms)
{
        struct smb2_create_req *req = iov[0].iov_base;
        unsigned int num = *num_iovec;

        iov[num].iov_base = create_durable_v2_buf(oparms);
        if (iov[num].iov_base == NULL)
                return -ENOMEM;
        iov[num].iov_len = sizeof(struct create_durable_v2);
        if (!req->CreateContextsOffset)
                req->CreateContextsOffset =
                        cpu_to_le32(sizeof(struct smb2_create_req) +
                                                                iov[1].iov_len);
        le32_add_cpu(&req->CreateContextsLength, sizeof(struct create_durable_v2));
        *num_iovec = num + 1;
        return 0;
}

static int
add_durable_reconnect_v2_context(struct kvec *iov, unsigned int *num_iovec,
                    struct cifs_open_parms *oparms)
{
        struct smb2_create_req *req = iov[0].iov_base;
        unsigned int num = *num_iovec;

        /* indicate that we don't need to relock the file */
        oparms->reconnect = false;

        iov[num].iov_base = create_reconnect_durable_v2_buf(oparms->fid);
        if (iov[num].iov_base == NULL)
                return -ENOMEM;
        iov[num].iov_len = sizeof(struct create_durable_handle_reconnect_v2);
        if (!req->CreateContextsOffset)
                req->CreateContextsOffset =
                        cpu_to_le32(sizeof(struct smb2_create_req) +
                                                                iov[1].iov_len);
        le32_add_cpu(&req->CreateContextsLength,
                        sizeof(struct create_durable_handle_reconnect_v2));
        *num_iovec = num + 1;
        return 0;
}

static int
add_durable_context(struct kvec *iov, unsigned int *num_iovec,
                    struct cifs_open_parms *oparms, bool use_persistent)
{
        struct smb2_create_req *req = iov[0].iov_base;
        unsigned int num = *num_iovec;

        if (use_persistent) {
                if (oparms->reconnect)
                        return add_durable_reconnect_v2_context(iov, num_iovec,
                                                                oparms);
                else
                        return add_durable_v2_context(iov, num_iovec, oparms);
        }

        if (oparms->reconnect) {
                iov[num].iov_base = create_reconnect_durable_buf(oparms->fid);
                /* indicate that we don't need to relock the file */
                oparms->reconnect = false;
        } else
                iov[num].iov_base = create_durable_buf();
        if (iov[num].iov_base == NULL)
                return -ENOMEM;
        iov[num].iov_len = sizeof(struct create_durable);
        if (!req->CreateContextsOffset)
                req->CreateContextsOffset =
                        cpu_to_le32(sizeof(struct smb2_create_req) +
                                                                iov[1].iov_len);
        le32_add_cpu(&req->CreateContextsLength, sizeof(struct create_durable));
        *num_iovec = num + 1;
        return 0;
}

/* See MS-SMB2 2.2.13.2.7 */
static struct crt_twarp_ctxt *
create_twarp_buf(__u64 timewarp)
{
        struct crt_twarp_ctxt *buf;

        buf = kzalloc(sizeof(struct crt_twarp_ctxt), GFP_KERNEL);
        if (!buf)
                return NULL;

        buf->ccontext.DataOffset = cpu_to_le16(offsetof
                                        (struct crt_twarp_ctxt, Timestamp));
        buf->ccontext.DataLength = cpu_to_le32(8);
        buf->ccontext.NameOffset = cpu_to_le16(offsetof
                                (struct crt_twarp_ctxt, Name));
        buf->ccontext.NameLength = cpu_to_le16(4);
        /* SMB2_CREATE_TIMEWARP_TOKEN is "TWrp" */
        buf->Name[0] = 'T';
        buf->Name[1] = 'W';
        buf->Name[2] = 'r';
        buf->Name[3] = 'p';
        buf->Timestamp = cpu_to_le64(timewarp);
        return buf;
}

/* See MS-SMB2 2.2.13.2.7 */
static int
add_twarp_context(struct kvec *iov, unsigned int *num_iovec, __u64 timewarp)
{
        struct smb2_create_req *req = iov[0].iov_base;
        unsigned int num = *num_iovec;

        iov[num].iov_base = create_twarp_buf(timewarp);
        if (iov[num].iov_base == NULL)
                return -ENOMEM;
        iov[num].iov_len = sizeof(struct crt_twarp_ctxt);
        if (!req->CreateContextsOffset)
                req->CreateContextsOffset = cpu_to_le32(
                                sizeof(struct smb2_create_req) +
                                iov[num - 1].iov_len);
        le32_add_cpu(&req->CreateContextsLength, sizeof(struct crt_twarp_ctxt));
        *num_iovec = num + 1;
        return 0;
}

/* See MS-SMB2 2.2.13.2.2 and MS-DTYP 2.4.6 */
static struct crt_sd_ctxt *
create_sd_buf(umode_t mode, unsigned int *len)
{
        struct crt_sd_ctxt *buf;
        struct cifs_ace *pace;
        unsigned int sdlen, acelen;

        *len = roundup(sizeof(struct crt_sd_ctxt) + sizeof(struct cifs_ace), 8);
        buf = kzalloc(*len, GFP_KERNEL);
        if (buf == NULL)
                return buf;

        sdlen = sizeof(struct smb3_sd) + sizeof(struct smb3_acl) +
                 sizeof(struct cifs_ace);

        buf->ccontext.DataOffset = cpu_to_le16(offsetof
                                        (struct crt_sd_ctxt, sd));
        buf->ccontext.DataLength = cpu_to_le32(sdlen);
        buf->ccontext.NameOffset = cpu_to_le16(offsetof
                                (struct crt_sd_ctxt, Name));
        buf->ccontext.NameLength = cpu_to_le16(4);
        /* SMB2_CREATE_SD_BUFFER_TOKEN is "SecD" */
        buf->Name[0] = 'S';
        buf->Name[1] = 'e';
        buf->Name[2] = 'c';
        buf->Name[3] = 'D';
        buf->sd.Revision = 1;  /* Must be one see MS-DTYP 2.4.6 */
        /*
         * ACL is "self relative" ie ACL is stored in contiguous block of memory
         * and "DP" ie the DACL is present
         */
        buf->sd.Control = cpu_to_le16(ACL_CONTROL_SR | ACL_CONTROL_DP);

        /* offset owner, group and Sbz1 and SACL are all zero */
        buf->sd.OffsetDacl = cpu_to_le32(sizeof(struct smb3_sd));
        buf->acl.AclRevision = ACL_REVISION; /* See 2.4.4.1 of MS-DTYP */

        /* create one ACE to hold the mode embedded in reserved special SID */
        pace = (struct cifs_ace *)(sizeof(struct crt_sd_ctxt) + (char *)buf);
        acelen = setup_special_mode_ACE(pace, (__u64)mode);
        buf->acl.AclSize = cpu_to_le16(sizeof(struct cifs_acl) + acelen);
        buf->acl.AceCount = cpu_to_le16(1);
        return buf;
}

static int
add_sd_context(struct kvec *iov, unsigned int *num_iovec, umode_t mode)
{
        struct smb2_create_req *req = iov[0].iov_base;
        unsigned int num = *num_iovec;
        unsigned int len = 0;

        iov[num].iov_base = create_sd_buf(mode, &len);
        if (iov[num].iov_base == NULL)
                return -ENOMEM;
        iov[num].iov_len = len;
        if (!req->CreateContextsOffset)
                req->CreateContextsOffset = cpu_to_le32(
                                sizeof(struct smb2_create_req) +
                                iov[num - 1].iov_len);
        le32_add_cpu(&req->CreateContextsLength, len);
        *num_iovec = num + 1;
        return 0;
}

static struct crt_query_id_ctxt *
create_query_id_buf(void)
{
        struct crt_query_id_ctxt *buf;

        buf = kzalloc(sizeof(struct crt_query_id_ctxt), GFP_KERNEL);
        if (!buf)
                return NULL;

        buf->ccontext.DataOffset = cpu_to_le16(0);
        buf->ccontext.DataLength = cpu_to_le32(0);
        buf->ccontext.NameOffset = cpu_to_le16(offsetof
                                (struct crt_query_id_ctxt, Name));
        buf->ccontext.NameLength = cpu_to_le16(4);
        /* SMB2_CREATE_QUERY_ON_DISK_ID is "QFid" */
        buf->Name[0] = 'Q';
        buf->Name[1] = 'F';
        buf->Name[2] = 'i';
        buf->Name[3] = 'd';
        return buf;
}

/* See MS-SMB2 2.2.13.2.9 */
static int
add_query_id_context(struct kvec *iov, unsigned int *num_iovec)
{
        struct smb2_create_req *req = iov[0].iov_base;
        unsigned int num = *num_iovec;

        iov[num].iov_base = create_query_id_buf();
        if (iov[num].iov_base == NULL)
                return -ENOMEM;
        iov[num].iov_len = sizeof(struct crt_query_id_ctxt);
        if (!req->CreateContextsOffset)
                req->CreateContextsOffset = cpu_to_le32(
                                sizeof(struct smb2_create_req) +
                                iov[num - 1].iov_len);
        le32_add_cpu(&req->CreateContextsLength, sizeof(struct crt_query_id_ctxt));
        *num_iovec = num + 1;
        return 0;
}

static int
alloc_path_with_tree_prefix(__le16 **out_path, int *out_size, int *out_len,
                            const char *treename, const __le16 *path)
{
        int treename_len, path_len;
        struct nls_table *cp;
        const __le16 sep[] = {cpu_to_le16('\\'), cpu_to_le16(0x0000)};

        /*
         * skip leading "\\"
         */
        treename_len = strlen(treename);
        if (treename_len < 2 || !(treename[0] == '\\' && treename[1] == '\\'))
                return -EINVAL;

        treename += 2;
        treename_len -= 2;

        path_len = UniStrnlen((wchar_t *)path, PATH_MAX);

        /*
         * make room for one path separator between the treename and
         * path
         */
        *out_len = treename_len + 1 + path_len;

        /*
         * final path needs to be null-terminated UTF16 with a
         * size aligned to 8
         */

        *out_size = roundup((*out_len+1)*2, 8);
        *out_path = kzalloc(*out_size, GFP_KERNEL);
        if (!*out_path)
                return -ENOMEM;

        cp = load_nls_default();
        cifs_strtoUTF16(*out_path, treename, treename_len, cp);
        UniStrcat(*out_path, sep);
        UniStrcat(*out_path, path);
        unload_nls(cp);

        return 0;
}

int smb311_posix_mkdir(const unsigned int xid, struct inode *inode,
                               umode_t mode, struct cifs_tcon *tcon,
                               const char *full_path,
                               struct cifs_sb_info *cifs_sb)
{
        struct smb_rqst rqst;
        struct smb2_create_req *req;
        struct smb2_create_rsp *rsp = NULL;
        struct cifs_ses *ses = tcon->ses;
        struct kvec iov[3]; /* make sure at least one for each open context */
        struct kvec rsp_iov = {NULL, 0};
        int resp_buftype;
        int uni_path_len;
        __le16 *copy_path = NULL;
        int copy_size;
        int rc = 0;
        unsigned int n_iov = 2;
        __u32 file_attributes = 0;
        char *pc_buf = NULL;
        int flags = 0;
        unsigned int total_len;
        __le16 *utf16_path = NULL;

        cifs_dbg(FYI, "mkdir\n");

        /* resource #1: path allocation */
        utf16_path = cifs_convert_path_to_utf16(full_path, cifs_sb);
        if (!utf16_path)
                return -ENOMEM;

        if (!ses || !(ses->server)) {
                rc = -EIO;
                goto err_free_path;
        }

        /* resource #2: request */
        rc = smb2_plain_req_init(SMB2_CREATE, tcon, (void **) &req, &total_len);
        if (rc)
                goto err_free_path;


        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        req->ImpersonationLevel = IL_IMPERSONATION;
        req->DesiredAccess = cpu_to_le32(FILE_WRITE_ATTRIBUTES);
        /* File attributes ignored on open (used in create though) */
        req->FileAttributes = cpu_to_le32(file_attributes);
        req->ShareAccess = FILE_SHARE_ALL_LE;
        req->CreateDisposition = cpu_to_le32(FILE_CREATE);
        req->CreateOptions = cpu_to_le32(CREATE_NOT_FILE);

        iov[0].iov_base = (char *)req;
        /* -1 since last byte is buf[0] which is sent below (path) */
        iov[0].iov_len = total_len - 1;

        req->NameOffset = cpu_to_le16(sizeof(struct smb2_create_req));

        /* [MS-SMB2] 2.2.13 NameOffset:
         * If SMB2_FLAGS_DFS_OPERATIONS is set in the Flags field of
         * the SMB2 header, the file name includes a prefix that will
         * be processed during DFS name normalization as specified in
         * section 3.3.5.9. Otherwise, the file name is relative to
         * the share that is identified by the TreeId in the SMB2
         * header.
         */
        if (tcon->share_flags & SHI1005_FLAGS_DFS) {
                int name_len;

                req->sync_hdr.Flags |= SMB2_FLAGS_DFS_OPERATIONS;
                rc = alloc_path_with_tree_prefix(&copy_path, &copy_size,
                                                 &name_len,
                                                 tcon->treeName, utf16_path);
                if (rc)
                        goto err_free_req;

                req->NameLength = cpu_to_le16(name_len * 2);
                uni_path_len = copy_size;
                /* free before overwriting resource */
                kfree(utf16_path);
                utf16_path = copy_path;
        } else {
                uni_path_len = (2 * UniStrnlen((wchar_t *)utf16_path, PATH_MAX)) + 2;
                /* MUST set path len (NameLength) to 0 opening root of share */
                req->NameLength = cpu_to_le16(uni_path_len - 2);
                if (uni_path_len % 8 != 0) {
                        copy_size = roundup(uni_path_len, 8);
                        copy_path = kzalloc(copy_size, GFP_KERNEL);
                        if (!copy_path) {
                                rc = -ENOMEM;
                                goto err_free_req;
                        }
                        memcpy((char *)copy_path, (const char *)utf16_path,
                               uni_path_len);
                        uni_path_len = copy_size;
                        /* free before overwriting resource */
                        kfree(utf16_path);
                        utf16_path = copy_path;
                }
        }

        iov[1].iov_len = uni_path_len;
        iov[1].iov_base = utf16_path;
        req->RequestedOplockLevel = SMB2_OPLOCK_LEVEL_NONE;

        if (tcon->posix_extensions) {
                /* resource #3: posix buf */
                rc = add_posix_context(iov, &n_iov, mode);
                if (rc)
                        goto err_free_req;
                pc_buf = iov[n_iov-1].iov_base;
        }


        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = iov;
        rqst.rq_nvec = n_iov;

        /* no need to inc num_remote_opens because we close it just below */
        trace_smb3_posix_mkdir_enter(xid, tcon->tid, ses->Suid, CREATE_NOT_FILE,
                                    FILE_WRITE_ATTRIBUTES);
        /* resource #4: response buffer */
        rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
        if (rc) {
                cifs_stats_fail_inc(tcon, SMB2_CREATE_HE);
                trace_smb3_posix_mkdir_err(xid, tcon->tid, ses->Suid,
                                           CREATE_NOT_FILE,
                                           FILE_WRITE_ATTRIBUTES, rc);
                goto err_free_rsp_buf;
        }

        rsp = (struct smb2_create_rsp *)rsp_iov.iov_base;
        trace_smb3_posix_mkdir_done(xid, rsp->PersistentFileId, tcon->tid,
                                    ses->Suid, CREATE_NOT_FILE,
                                    FILE_WRITE_ATTRIBUTES);

        SMB2_close(xid, tcon, rsp->PersistentFileId, rsp->VolatileFileId);

        /* Eventually save off posix specific response info and timestaps */

err_free_rsp_buf:
        free_rsp_buf(resp_buftype, rsp);
        kfree(pc_buf);
err_free_req:
        cifs_small_buf_release(req);
err_free_path:
        kfree(utf16_path);
        return rc;
}

int
SMB2_open_init(struct cifs_tcon *tcon, struct smb_rqst *rqst, __u8 *oplock,
               struct cifs_open_parms *oparms, __le16 *path)
{
        struct TCP_Server_Info *server = tcon->ses->server;
        struct smb2_create_req *req;
        unsigned int n_iov = 2;
        __u32 file_attributes = 0;
        int copy_size;
        int uni_path_len;
        unsigned int total_len;
        struct kvec *iov = rqst->rq_iov;
        __le16 *copy_path;
        int rc;

        rc = smb2_plain_req_init(SMB2_CREATE, tcon, (void **) &req, &total_len);
        if (rc)
                return rc;

        iov[0].iov_base = (char *)req;
        /* -1 since last byte is buf[0] which is sent below (path) */
        iov[0].iov_len = total_len - 1;

        if (oparms->create_options & CREATE_OPTION_READONLY)
                file_attributes |= ATTR_READONLY;
        if (oparms->create_options & CREATE_OPTION_SPECIAL)
                file_attributes |= ATTR_SYSTEM;

        req->ImpersonationLevel = IL_IMPERSONATION;
        req->DesiredAccess = cpu_to_le32(oparms->desired_access);
        /* File attributes ignored on open (used in create though) */
        req->FileAttributes = cpu_to_le32(file_attributes);
        req->ShareAccess = FILE_SHARE_ALL_LE;

        req->CreateDisposition = cpu_to_le32(oparms->disposition);
        req->CreateOptions = cpu_to_le32(oparms->create_options & CREATE_OPTIONS_MASK);
        req->NameOffset = cpu_to_le16(sizeof(struct smb2_create_req));

        /* [MS-SMB2] 2.2.13 NameOffset:
         * If SMB2_FLAGS_DFS_OPERATIONS is set in the Flags field of
         * the SMB2 header, the file name includes a prefix that will
         * be processed during DFS name normalization as specified in
         * section 3.3.5.9. Otherwise, the file name is relative to
         * the share that is identified by the TreeId in the SMB2
         * header.
         */
        if (tcon->share_flags & SHI1005_FLAGS_DFS) {
                int name_len;

                req->sync_hdr.Flags |= SMB2_FLAGS_DFS_OPERATIONS;
                rc = alloc_path_with_tree_prefix(&copy_path, &copy_size,
                                                 &name_len,
                                                 tcon->treeName, path);
                if (rc)
                        return rc;
                req->NameLength = cpu_to_le16(name_len * 2);
                uni_path_len = copy_size;
                path = copy_path;
        } else {
                uni_path_len = (2 * UniStrnlen((wchar_t *)path, PATH_MAX)) + 2;
                /* MUST set path len (NameLength) to 0 opening root of share */
                req->NameLength = cpu_to_le16(uni_path_len - 2);
                copy_size = uni_path_len;
                if (copy_size % 8 != 0)
                        copy_size = roundup(copy_size, 8);
                copy_path = kzalloc(copy_size, GFP_KERNEL);
                if (!copy_path)
                        return -ENOMEM;
                memcpy((char *)copy_path, (const char *)path,
                       uni_path_len);
                uni_path_len = copy_size;
                path = copy_path;
        }

        iov[1].iov_len = uni_path_len;
        iov[1].iov_base = path;

        if ((!server->oplocks) || (tcon->no_lease))
                *oplock = SMB2_OPLOCK_LEVEL_NONE;

        if (!(server->capabilities & SMB2_GLOBAL_CAP_LEASING) ||
            *oplock == SMB2_OPLOCK_LEVEL_NONE)
                req->RequestedOplockLevel = *oplock;
        else if (!(server->capabilities & SMB2_GLOBAL_CAP_DIRECTORY_LEASING) &&
                  (oparms->create_options & CREATE_NOT_FILE))
                req->RequestedOplockLevel = *oplock; /* no srv lease support */
        else {
                rc = add_lease_context(server, iov, &n_iov,
                                       oparms->fid->lease_key, oplock);
                if (rc)
                        return rc;
        }

        if (*oplock == SMB2_OPLOCK_LEVEL_BATCH) {
                /* need to set Next field of lease context if we request it */
                if (server->capabilities & SMB2_GLOBAL_CAP_LEASING) {
                        struct create_context *ccontext =
                            (struct create_context *)iov[n_iov-1].iov_base;
                        ccontext->Next =
                                cpu_to_le32(server->vals->create_lease_size);
                }

                rc = add_durable_context(iov, &n_iov, oparms,
                                        tcon->use_persistent);
                if (rc)
                        return rc;
        }

        if (tcon->posix_extensions) {
                if (n_iov > 2) {
                        struct create_context *ccontext =
                            (struct create_context *)iov[n_iov-1].iov_base;
                        ccontext->Next =
                                cpu_to_le32(iov[n_iov-1].iov_len);
                }

                rc = add_posix_context(iov, &n_iov, oparms->mode);
                if (rc)
                        return rc;
        }

        if (tcon->snapshot_time) {
                cifs_dbg(FYI, "adding snapshot context\n");
                if (n_iov > 2) {
                        struct create_context *ccontext =
                            (struct create_context *)iov[n_iov-1].iov_base;
                        ccontext->Next =
                                cpu_to_le32(iov[n_iov-1].iov_len);
                }

                rc = add_twarp_context(iov, &n_iov, tcon->snapshot_time);
                if (rc)
                        return rc;
        }

        if ((oparms->disposition != FILE_OPEN) &&
            (oparms->cifs_sb) &&
            (oparms->cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MODE_FROM_SID) &&
            (oparms->mode != ACL_NO_MODE)) {
                if (n_iov > 2) {
                        struct create_context *ccontext =
                            (struct create_context *)iov[n_iov-1].iov_base;
                        ccontext->Next =
                                cpu_to_le32(iov[n_iov-1].iov_len);
                }

                cifs_dbg(FYI, "add sd with mode 0x%x\n", oparms->mode);
                rc = add_sd_context(iov, &n_iov, oparms->mode);
                if (rc)
                        return rc;
        }

        if (n_iov > 2) {
                struct create_context *ccontext =
                        (struct create_context *)iov[n_iov-1].iov_base;
                ccontext->Next = cpu_to_le32(iov[n_iov-1].iov_len);
        }
        add_query_id_context(iov, &n_iov);

        rqst->rq_nvec = n_iov;
        return 0;
}

/* rq_iov[0] is the request and is released by cifs_small_buf_release().
 * All other vectors are freed by kfree().
 */
void
SMB2_open_free(struct smb_rqst *rqst)
{
        int i;

        if (rqst && rqst->rq_iov) {
                cifs_small_buf_release(rqst->rq_iov[0].iov_base);
                for (i = 1; i < rqst->rq_nvec; i++)
                        if (rqst->rq_iov[i].iov_base != smb2_padding)
                                kfree(rqst->rq_iov[i].iov_base);
        }
}

int
SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
          __u8 *oplock, struct smb2_file_all_info *buf,
          struct kvec *err_iov, int *buftype)
{
        struct smb_rqst rqst;
        struct smb2_create_rsp *rsp = NULL;
        struct TCP_Server_Info *server;
        struct cifs_tcon *tcon = oparms->tcon;
        struct cifs_ses *ses = tcon->ses;
        struct kvec iov[SMB2_CREATE_IOV_SIZE];
        struct kvec rsp_iov = {NULL, 0};
        int resp_buftype = CIFS_NO_BUFFER;
        int rc = 0;
        int flags = 0;

        cifs_dbg(FYI, "create/open\n");
        if (ses && (ses->server))
                server = ses->server;
        else
                return -EIO;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        memset(&iov, 0, sizeof(iov));
        rqst.rq_iov = iov;
        rqst.rq_nvec = SMB2_CREATE_IOV_SIZE;

        rc = SMB2_open_init(tcon, &rqst, oplock, oparms, path);
        if (rc)
                goto creat_exit;

        trace_smb3_open_enter(xid, tcon->tid, tcon->ses->Suid,
                oparms->create_options, oparms->desired_access);

        rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags,
                            &rsp_iov);
        rsp = (struct smb2_create_rsp *)rsp_iov.iov_base;

        if (rc != 0) {
                cifs_stats_fail_inc(tcon, SMB2_CREATE_HE);
                if (err_iov && rsp) {
                        *err_iov = rsp_iov;
                        *buftype = resp_buftype;
                        resp_buftype = CIFS_NO_BUFFER;
                        rsp = NULL;
                }
                trace_smb3_open_err(xid, tcon->tid, ses->Suid,
                                    oparms->create_options, oparms->desired_access, rc);
                if (rc == -EREMCHG) {
                        printk_once(KERN_WARNING "server share %s deleted\n",
                                    tcon->treeName);
                        tcon->need_reconnect = true;
                }
                goto creat_exit;
        } else
                trace_smb3_open_done(xid, rsp->PersistentFileId, tcon->tid,
                                     ses->Suid, oparms->create_options,
                                     oparms->desired_access);

        atomic_inc(&tcon->num_remote_opens);
        oparms->fid->persistent_fid = rsp->PersistentFileId;
        oparms->fid->volatile_fid = rsp->VolatileFileId;
#ifdef CONFIG_CIFS_DEBUG2
        oparms->fid->mid = le64_to_cpu(rsp->sync_hdr.MessageId);
#endif /* CIFS_DEBUG2 */

        if (buf) {
                memcpy(buf, &rsp->CreationTime, 32);
                buf->AllocationSize = rsp->AllocationSize;
                buf->EndOfFile = rsp->EndofFile;
                buf->Attributes = rsp->FileAttributes;
                buf->NumberOfLinks = cpu_to_le32(1);
                buf->DeletePending = 0;
        }


        smb2_parse_contexts(server, rsp, &oparms->fid->epoch,
                            oparms->fid->lease_key, oplock, buf);
creat_exit:
        SMB2_open_free(&rqst);
        free_rsp_buf(resp_buftype, rsp);
        return rc;
}

int
SMB2_ioctl_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
                u64 persistent_fid, u64 volatile_fid, u32 opcode,
                bool is_fsctl, char *in_data, u32 indatalen,
                __u32 max_response_size)
{
        struct smb2_ioctl_req *req;
        struct kvec *iov = rqst->rq_iov;
        unsigned int total_len;
        int rc;
        char *in_data_buf;

        rc = smb2_ioctl_req_init(opcode, tcon, (void **) &req, &total_len);
        if (rc)
                return rc;

        if (indatalen) {
                /*
                 * indatalen is usually small at a couple of bytes max, so
                 * just allocate through generic pool
                 */
                in_data_buf = kmemdup(in_data, indatalen, GFP_NOFS);
                if (!in_data_buf) {
                        cifs_small_buf_release(req);
                        return -ENOMEM;
                }
        }

        req->CtlCode = cpu_to_le32(opcode);
        req->PersistentFileId = persistent_fid;
        req->VolatileFileId = volatile_fid;

        iov[0].iov_base = (char *)req;
        /*
         * If no input data, the size of ioctl struct in
         * protocol spec still includes a 1 byte data buffer,
         * but if input data passed to ioctl, we do not
         * want to double count this, so we do not send
         * the dummy one byte of data in iovec[0] if sending
         * input data (in iovec[1]).
         */
        if (indatalen) {
                req->InputCount = cpu_to_le32(indatalen);
                /* do not set InputOffset if no input data */
                req->InputOffset =
                       cpu_to_le32(offsetof(struct smb2_ioctl_req, Buffer));
                rqst->rq_nvec = 2;
                iov[0].iov_len = total_len - 1;
                iov[1].iov_base = in_data_buf;
                iov[1].iov_len = indatalen;
        } else {
                rqst->rq_nvec = 1;
                iov[0].iov_len = total_len;
        }

        req->OutputOffset = 0;
        req->OutputCount = 0; /* MBZ */

        /*
         * In most cases max_response_size is set to 16K (CIFSMaxBufSize)
         * We Could increase default MaxOutputResponse, but that could require
         * more credits. Windows typically sets this smaller, but for some
         * ioctls it may be useful to allow server to send more. No point
         * limiting what the server can send as long as fits in one credit
         * We can not handle more than CIFS_MAX_BUF_SIZE yet but may want
         * to increase this limit up in the future.
         * Note that for snapshot queries that servers like Azure expect that
         * the first query be minimal size (and just used to get the number/size
         * of previous versions) so response size must be specified as EXACTLY
         * sizeof(struct snapshot_array) which is 16 when rounded up to multiple
         * of eight bytes.  Currently that is the only case where we set max
         * response size smaller.
         */
        req->MaxOutputResponse = cpu_to_le32(max_response_size);

        if (is_fsctl)
                req->Flags = cpu_to_le32(SMB2_0_IOCTL_IS_FSCTL);
        else
                req->Flags = 0;

        /* validate negotiate request must be signed - see MS-SMB2 3.2.5.5 */
        if (opcode == FSCTL_VALIDATE_NEGOTIATE_INFO)
                req->sync_hdr.Flags |= SMB2_FLAGS_SIGNED;

        return 0;
}

void
SMB2_ioctl_free(struct smb_rqst *rqst)
{
        int i;
        if (rqst && rqst->rq_iov) {
                cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */
                for (i = 1; i < rqst->rq_nvec; i++)
                        if (rqst->rq_iov[i].iov_base != smb2_padding)
                                kfree(rqst->rq_iov[i].iov_base);
        }
}


/*
 *      SMB2 IOCTL is used for both IOCTLs and FSCTLs
 */
int
SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
           u64 volatile_fid, u32 opcode, bool is_fsctl,
           char *in_data, u32 indatalen, u32 max_out_data_len,
           char **out_data, u32 *plen /* returned data len */)
{
        struct smb_rqst rqst;
        struct smb2_ioctl_rsp *rsp = NULL;
        struct cifs_ses *ses;
        struct kvec iov[SMB2_IOCTL_IOV_SIZE];
        struct kvec rsp_iov = {NULL, 0};
        int resp_buftype = CIFS_NO_BUFFER;
        int rc = 0;
        int flags = 0;
        struct TCP_Server_Info *server;

        cifs_dbg(FYI, "SMB2 IOCTL\n");

        if (out_data != NULL)
                *out_data = NULL;

        /* zero out returned data len, in case of error */
        if (plen)
                *plen = 0;

        if (tcon)
                ses = tcon->ses;
        else
                return -EIO;

        if (!ses)
                return -EIO;
        server = ses->server;
        if (!server)
                return -EIO;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        memset(&iov, 0, sizeof(iov));
        rqst.rq_iov = iov;
        rqst.rq_nvec = SMB2_IOCTL_IOV_SIZE;

        rc = SMB2_ioctl_init(tcon, &rqst, persistent_fid, volatile_fid, opcode,
                             is_fsctl, in_data, indatalen, max_out_data_len);
        if (rc)
                goto ioctl_exit;

        rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags,
                            &rsp_iov);
        rsp = (struct smb2_ioctl_rsp *)rsp_iov.iov_base;

        if (rc != 0)
                trace_smb3_fsctl_err(xid, persistent_fid, tcon->tid,
                                ses->Suid, 0, opcode, rc);

        if ((rc != 0) && (rc != -EINVAL) && (rc != -E2BIG)) {
                cifs_stats_fail_inc(tcon, SMB2_IOCTL_HE);
                goto ioctl_exit;
        } else if (rc == -EINVAL) {
                if ((opcode != FSCTL_SRV_COPYCHUNK_WRITE) &&
                    (opcode != FSCTL_SRV_COPYCHUNK)) {
                        cifs_stats_fail_inc(tcon, SMB2_IOCTL_HE);
                        goto ioctl_exit;
                }
        } else if (rc == -E2BIG) {
                if (opcode != FSCTL_QUERY_ALLOCATED_RANGES) {
                        cifs_stats_fail_inc(tcon, SMB2_IOCTL_HE);
                        goto ioctl_exit;
                }
        }

        /* check if caller wants to look at return data or just return rc */
        if ((plen == NULL) || (out_data == NULL))
                goto ioctl_exit;

        *plen = le32_to_cpu(rsp->OutputCount);

        /* We check for obvious errors in the output buffer length and offset */
        if (*plen == 0)
                goto ioctl_exit; /* server returned no data */
        else if (*plen > rsp_iov.iov_len || *plen > 0xFF00) {
                cifs_tcon_dbg(VFS, "srv returned invalid ioctl length: %d\n", *plen);
                *plen = 0;
                rc = -EIO;
                goto ioctl_exit;
        }

        if (rsp_iov.iov_len - *plen < le32_to_cpu(rsp->OutputOffset)) {
                cifs_tcon_dbg(VFS, "Malformed ioctl resp: len %d offset %d\n", *plen,
                        le32_to_cpu(rsp->OutputOffset));
                *plen = 0;
                rc = -EIO;
                goto ioctl_exit;
        }

        *out_data = kmemdup((char *)rsp + le32_to_cpu(rsp->OutputOffset),
                            *plen, GFP_KERNEL);
        if (*out_data == NULL) {
                rc = -ENOMEM;
                goto ioctl_exit;
        }

ioctl_exit:
        SMB2_ioctl_free(&rqst);
        free_rsp_buf(resp_buftype, rsp);
        return rc;
}

/*
 *   Individual callers to ioctl worker function follow
 */

int
SMB2_set_compression(const unsigned int xid, struct cifs_tcon *tcon,
                     u64 persistent_fid, u64 volatile_fid)
{
        int rc;
        struct  compress_ioctl fsctl_input;
        char *ret_data = NULL;

        fsctl_input.CompressionState =
                        cpu_to_le16(COMPRESSION_FORMAT_DEFAULT);

        rc = SMB2_ioctl(xid, tcon, persistent_fid, volatile_fid,
                        FSCTL_SET_COMPRESSION, true /* is_fsctl */,
                        (char *)&fsctl_input /* data input */,
                        2 /* in data len */, CIFSMaxBufSize /* max out data */,
                        &ret_data /* out data */, NULL);

        cifs_dbg(FYI, "set compression rc %d\n", rc);

        return rc;
}