Merge branches 'for-5.1/upstream-fixes' and 'for-5.2/core' into for-linus

[mirror_ubuntu-focal-kernel.git] / fs / cifs / sess.c

/*
 *   fs/cifs/sess.c
 *
 *   SMB/CIFS session setup handling routines
 *
 *   Copyright (c) International Business Machines  Corp., 2006, 2009
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *
 *   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
 */

#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_unicode.h"
#include "cifs_debug.h"
#include "ntlmssp.h"
#include "nterr.h"
#include <linux/utsname.h>
#include <linux/slab.h>
#include "cifs_spnego.h"

static __u32 cifs_ssetup_hdr(struct cifs_ses *ses, SESSION_SETUP_ANDX *pSMB)
{
        __u32 capabilities = 0;

        /* init fields common to all four types of SessSetup */
        /* Note that offsets for first seven fields in req struct are same  */
        /*      in CIFS Specs so does not matter which of 3 forms of struct */
        /*      that we use in next few lines                               */
        /* Note that header is initialized to zero in header_assemble */
        pSMB->req.AndXCommand = 0xFF;
        pSMB->req.MaxBufferSize = cpu_to_le16(min_t(u32,
                                        CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4,
                                        USHRT_MAX));
        pSMB->req.MaxMpxCount = cpu_to_le16(ses->server->maxReq);
        pSMB->req.VcNumber = cpu_to_le16(1);

        /* Now no need to set SMBFLG_CASELESS or obsolete CANONICAL PATH */

        /* BB verify whether signing required on neg or just on auth frame
           (and NTLM case) */

        capabilities = CAP_LARGE_FILES | CAP_NT_SMBS | CAP_LEVEL_II_OPLOCKS |
                        CAP_LARGE_WRITE_X | CAP_LARGE_READ_X;

        if (ses->server->sign)
                pSMB->req.hdr.Flags2 |= SMBFLG2_SECURITY_SIGNATURE;

        if (ses->capabilities & CAP_UNICODE) {
                pSMB->req.hdr.Flags2 |= SMBFLG2_UNICODE;
                capabilities |= CAP_UNICODE;
        }
        if (ses->capabilities & CAP_STATUS32) {
                pSMB->req.hdr.Flags2 |= SMBFLG2_ERR_STATUS;
                capabilities |= CAP_STATUS32;
        }
        if (ses->capabilities & CAP_DFS) {
                pSMB->req.hdr.Flags2 |= SMBFLG2_DFS;
                capabilities |= CAP_DFS;
        }
        if (ses->capabilities & CAP_UNIX)
                capabilities |= CAP_UNIX;

        return capabilities;
}

static void
unicode_oslm_strings(char **pbcc_area, const struct nls_table *nls_cp)
{
        char *bcc_ptr = *pbcc_area;
        int bytes_ret = 0;

        /* Copy OS version */
        bytes_ret = cifs_strtoUTF16((__le16 *)bcc_ptr, "Linux version ", 32,
                                    nls_cp);
        bcc_ptr += 2 * bytes_ret;
        bytes_ret = cifs_strtoUTF16((__le16 *) bcc_ptr, init_utsname()->release,
                                    32, nls_cp);
        bcc_ptr += 2 * bytes_ret;
        bcc_ptr += 2; /* trailing null */

        bytes_ret = cifs_strtoUTF16((__le16 *) bcc_ptr, CIFS_NETWORK_OPSYS,
                                    32, nls_cp);
        bcc_ptr += 2 * bytes_ret;
        bcc_ptr += 2; /* trailing null */

        *pbcc_area = bcc_ptr;
}

static void unicode_domain_string(char **pbcc_area, struct cifs_ses *ses,
                                   const struct nls_table *nls_cp)
{
        char *bcc_ptr = *pbcc_area;
        int bytes_ret = 0;

        /* copy domain */
        if (ses->domainName == NULL) {
                /* Sending null domain better than using a bogus domain name (as
                we did briefly in 2.6.18) since server will use its default */
                *bcc_ptr = 0;
                *(bcc_ptr+1) = 0;
                bytes_ret = 0;
        } else
                bytes_ret = cifs_strtoUTF16((__le16 *) bcc_ptr, ses->domainName,
                                            CIFS_MAX_DOMAINNAME_LEN, nls_cp);
        bcc_ptr += 2 * bytes_ret;
        bcc_ptr += 2;  /* account for null terminator */

        *pbcc_area = bcc_ptr;
}


static void unicode_ssetup_strings(char **pbcc_area, struct cifs_ses *ses,
                                   const struct nls_table *nls_cp)
{
        char *bcc_ptr = *pbcc_area;
        int bytes_ret = 0;

        /* BB FIXME add check that strings total less
        than 335 or will need to send them as arrays */

        /* unicode strings, must be word aligned before the call */
/*      if ((long) bcc_ptr % 2) {
                *bcc_ptr = 0;
                bcc_ptr++;
        } */
        /* copy user */
        if (ses->user_name == NULL) {
                /* null user mount */
                *bcc_ptr = 0;
                *(bcc_ptr+1) = 0;
        } else {
                bytes_ret = cifs_strtoUTF16((__le16 *) bcc_ptr, ses->user_name,
                                            CIFS_MAX_USERNAME_LEN, nls_cp);
        }
        bcc_ptr += 2 * bytes_ret;
        bcc_ptr += 2; /* account for null termination */

        unicode_domain_string(&bcc_ptr, ses, nls_cp);
        unicode_oslm_strings(&bcc_ptr, nls_cp);

        *pbcc_area = bcc_ptr;
}

static void ascii_ssetup_strings(char **pbcc_area, struct cifs_ses *ses,
                                 const struct nls_table *nls_cp)
{
        char *bcc_ptr = *pbcc_area;

        /* copy user */
        /* BB what about null user mounts - check that we do this BB */
        /* copy user */
        if (ses->user_name != NULL) {
                strncpy(bcc_ptr, ses->user_name, CIFS_MAX_USERNAME_LEN);
                bcc_ptr += strnlen(ses->user_name, CIFS_MAX_USERNAME_LEN);
        }
        /* else null user mount */
        *bcc_ptr = 0;
        bcc_ptr++; /* account for null termination */

        /* copy domain */
        if (ses->domainName != NULL) {
                strncpy(bcc_ptr, ses->domainName, CIFS_MAX_DOMAINNAME_LEN);
                bcc_ptr += strnlen(ses->domainName, CIFS_MAX_DOMAINNAME_LEN);
        } /* else we will send a null domain name
             so the server will default to its own domain */
        *bcc_ptr = 0;
        bcc_ptr++;

        /* BB check for overflow here */

        strcpy(bcc_ptr, "Linux version ");
        bcc_ptr += strlen("Linux version ");
        strcpy(bcc_ptr, init_utsname()->release);
        bcc_ptr += strlen(init_utsname()->release) + 1;

        strcpy(bcc_ptr, CIFS_NETWORK_OPSYS);
        bcc_ptr += strlen(CIFS_NETWORK_OPSYS) + 1;

        *pbcc_area = bcc_ptr;
}

static void
decode_unicode_ssetup(char **pbcc_area, int bleft, struct cifs_ses *ses,
                      const struct nls_table *nls_cp)
{
        int len;
        char *data = *pbcc_area;

        cifs_dbg(FYI, "bleft %d\n", bleft);

        kfree(ses->serverOS);
        ses->serverOS = cifs_strndup_from_utf16(data, bleft, true, nls_cp);
        cifs_dbg(FYI, "serverOS=%s\n", ses->serverOS);
        len = (UniStrnlen((wchar_t *) data, bleft / 2) * 2) + 2;
        data += len;
        bleft -= len;
        if (bleft <= 0)
                return;

        kfree(ses->serverNOS);
        ses->serverNOS = cifs_strndup_from_utf16(data, bleft, true, nls_cp);
        cifs_dbg(FYI, "serverNOS=%s\n", ses->serverNOS);
        len = (UniStrnlen((wchar_t *) data, bleft / 2) * 2) + 2;
        data += len;
        bleft -= len;
        if (bleft <= 0)
                return;

        kfree(ses->serverDomain);
        ses->serverDomain = cifs_strndup_from_utf16(data, bleft, true, nls_cp);
        cifs_dbg(FYI, "serverDomain=%s\n", ses->serverDomain);

        return;
}

static void decode_ascii_ssetup(char **pbcc_area, __u16 bleft,
                                struct cifs_ses *ses,
                                const struct nls_table *nls_cp)
{
        int len;
        char *bcc_ptr = *pbcc_area;

        cifs_dbg(FYI, "decode sessetup ascii. bleft %d\n", bleft);

        len = strnlen(bcc_ptr, bleft);
        if (len >= bleft)
                return;

        kfree(ses->serverOS);

        ses->serverOS = kzalloc(len + 1, GFP_KERNEL);
        if (ses->serverOS) {
                strncpy(ses->serverOS, bcc_ptr, len);
                if (strncmp(ses->serverOS, "OS/2", 4) == 0)
                        cifs_dbg(FYI, "OS/2 server\n");
        }

        bcc_ptr += len + 1;
        bleft -= len + 1;

        len = strnlen(bcc_ptr, bleft);
        if (len >= bleft)
                return;

        kfree(ses->serverNOS);

        ses->serverNOS = kzalloc(len + 1, GFP_KERNEL);
        if (ses->serverNOS)
                strncpy(ses->serverNOS, bcc_ptr, len);

        bcc_ptr += len + 1;
        bleft -= len + 1;

        len = strnlen(bcc_ptr, bleft);
        if (len > bleft)
                return;

        /* No domain field in LANMAN case. Domain is
           returned by old servers in the SMB negprot response */
        /* BB For newer servers which do not support Unicode,
           but thus do return domain here we could add parsing
           for it later, but it is not very important */
        cifs_dbg(FYI, "ascii: bytes left %d\n", bleft);
}

int decode_ntlmssp_challenge(char *bcc_ptr, int blob_len,
                                    struct cifs_ses *ses)
{
        unsigned int tioffset; /* challenge message target info area */
        unsigned int tilen; /* challenge message target info area length  */

        CHALLENGE_MESSAGE *pblob = (CHALLENGE_MESSAGE *)bcc_ptr;

        if (blob_len < sizeof(CHALLENGE_MESSAGE)) {
                cifs_dbg(VFS, "challenge blob len %d too small\n", blob_len);
                return -EINVAL;
        }

        if (memcmp(pblob->Signature, "NTLMSSP", 8)) {
                cifs_dbg(VFS, "blob signature incorrect %s\n",
                         pblob->Signature);
                return -EINVAL;
        }
        if (pblob->MessageType != NtLmChallenge) {
                cifs_dbg(VFS, "Incorrect message type %d\n",
                         pblob->MessageType);
                return -EINVAL;
        }

        memcpy(ses->ntlmssp->cryptkey, pblob->Challenge, CIFS_CRYPTO_KEY_SIZE);
        /* BB we could decode pblob->NegotiateFlags; some may be useful */
        /* In particular we can examine sign flags */
        /* BB spec says that if AvId field of MsvAvTimestamp is populated then
                we must set the MIC field of the AUTHENTICATE_MESSAGE */
        ses->ntlmssp->server_flags = le32_to_cpu(pblob->NegotiateFlags);
        tioffset = le32_to_cpu(pblob->TargetInfoArray.BufferOffset);
        tilen = le16_to_cpu(pblob->TargetInfoArray.Length);
        if (tioffset > blob_len || tioffset + tilen > blob_len) {
                cifs_dbg(VFS, "tioffset + tilen too high %u + %u",
                        tioffset, tilen);
                return -EINVAL;
        }
        if (tilen) {
                ses->auth_key.response = kmemdup(bcc_ptr + tioffset, tilen,
                                                 GFP_KERNEL);
                if (!ses->auth_key.response) {
                        cifs_dbg(VFS, "Challenge target info alloc failure");
                        return -ENOMEM;
                }
                ses->auth_key.len = tilen;
        }

        return 0;
}

/* BB Move to ntlmssp.c eventually */

/* We do not malloc the blob, it is passed in pbuffer, because
   it is fixed size, and small, making this approach cleaner */
void build_ntlmssp_negotiate_blob(unsigned char *pbuffer,
                                         struct cifs_ses *ses)
{
        NEGOTIATE_MESSAGE *sec_blob = (NEGOTIATE_MESSAGE *)pbuffer;
        __u32 flags;

        memset(pbuffer, 0, sizeof(NEGOTIATE_MESSAGE));
        memcpy(sec_blob->Signature, NTLMSSP_SIGNATURE, 8);
        sec_blob->MessageType = NtLmNegotiate;

        /* BB is NTLMV2 session security format easier to use here? */
        flags = NTLMSSP_NEGOTIATE_56 |  NTLMSSP_REQUEST_TARGET |
                NTLMSSP_NEGOTIATE_128 | NTLMSSP_NEGOTIATE_UNICODE |
                NTLMSSP_NEGOTIATE_NTLM | NTLMSSP_NEGOTIATE_EXTENDED_SEC |
                NTLMSSP_NEGOTIATE_SEAL;
        if (ses->server->sign)
                flags |= NTLMSSP_NEGOTIATE_SIGN;
        if (!ses->server->session_estab || ses->ntlmssp->sesskey_per_smbsess)
                flags |= NTLMSSP_NEGOTIATE_KEY_XCH;

        sec_blob->NegotiateFlags = cpu_to_le32(flags);

        sec_blob->WorkstationName.BufferOffset = 0;
        sec_blob->WorkstationName.Length = 0;
        sec_blob->WorkstationName.MaximumLength = 0;

        /* Domain name is sent on the Challenge not Negotiate NTLMSSP request */
        sec_blob->DomainName.BufferOffset = 0;
        sec_blob->DomainName.Length = 0;
        sec_blob->DomainName.MaximumLength = 0;
}

static int size_of_ntlmssp_blob(struct cifs_ses *ses)
{
        int sz = sizeof(AUTHENTICATE_MESSAGE) + ses->auth_key.len
                - CIFS_SESS_KEY_SIZE + CIFS_CPHTXT_SIZE + 2;

        if (ses->domainName)
                sz += 2 * strnlen(ses->domainName, CIFS_MAX_DOMAINNAME_LEN);
        else
                sz += 2;

        if (ses->user_name)
                sz += 2 * strnlen(ses->user_name, CIFS_MAX_USERNAME_LEN);
        else
                sz += 2;

        return sz;
}

int build_ntlmssp_auth_blob(unsigned char **pbuffer,
                                        u16 *buflen,
                                   struct cifs_ses *ses,
                                   const struct nls_table *nls_cp)
{
        int rc;
        AUTHENTICATE_MESSAGE *sec_blob;
        __u32 flags;
        unsigned char *tmp;

        rc = setup_ntlmv2_rsp(ses, nls_cp);
        if (rc) {
                cifs_dbg(VFS, "Error %d during NTLMSSP authentication\n", rc);
                *buflen = 0;
                goto setup_ntlmv2_ret;
        }
        *pbuffer = kmalloc(size_of_ntlmssp_blob(ses), GFP_KERNEL);
        if (!*pbuffer) {
                rc = -ENOMEM;
                cifs_dbg(VFS, "Error %d during NTLMSSP allocation\n", rc);
                *buflen = 0;
                goto setup_ntlmv2_ret;
        }
        sec_blob = (AUTHENTICATE_MESSAGE *)*pbuffer;

        memcpy(sec_blob->Signature, NTLMSSP_SIGNATURE, 8);
        sec_blob->MessageType = NtLmAuthenticate;

        flags = NTLMSSP_NEGOTIATE_56 |
                NTLMSSP_REQUEST_TARGET | NTLMSSP_NEGOTIATE_TARGET_INFO |
                NTLMSSP_NEGOTIATE_128 | NTLMSSP_NEGOTIATE_UNICODE |
                NTLMSSP_NEGOTIATE_NTLM | NTLMSSP_NEGOTIATE_EXTENDED_SEC |
                NTLMSSP_NEGOTIATE_SEAL;
        if (ses->server->sign)
                flags |= NTLMSSP_NEGOTIATE_SIGN;
        if (!ses->server->session_estab || ses->ntlmssp->sesskey_per_smbsess)
                flags |= NTLMSSP_NEGOTIATE_KEY_XCH;

        tmp = *pbuffer + sizeof(AUTHENTICATE_MESSAGE);
        sec_blob->NegotiateFlags = cpu_to_le32(flags);

        sec_blob->LmChallengeResponse.BufferOffset =
                                cpu_to_le32(sizeof(AUTHENTICATE_MESSAGE));
        sec_blob->LmChallengeResponse.Length = 0;
        sec_blob->LmChallengeResponse.MaximumLength = 0;

        sec_blob->NtChallengeResponse.BufferOffset =
                                cpu_to_le32(tmp - *pbuffer);
        if (ses->user_name != NULL) {
                memcpy(tmp, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
                                ses->auth_key.len - CIFS_SESS_KEY_SIZE);
                tmp += ses->auth_key.len - CIFS_SESS_KEY_SIZE;

                sec_blob->NtChallengeResponse.Length =
                                cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
                sec_blob->NtChallengeResponse.MaximumLength =
                                cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
        } else {
                /*
                 * don't send an NT Response for anonymous access
                 */
                sec_blob->NtChallengeResponse.Length = 0;
                sec_blob->NtChallengeResponse.MaximumLength = 0;
        }

        if (ses->domainName == NULL) {
                sec_blob->DomainName.BufferOffset = cpu_to_le32(tmp - *pbuffer);
                sec_blob->DomainName.Length = 0;
                sec_blob->DomainName.MaximumLength = 0;
                tmp += 2;
        } else {
                int len;
                len = cifs_strtoUTF16((__le16 *)tmp, ses->domainName,
                                      CIFS_MAX_DOMAINNAME_LEN, nls_cp);
                len *= 2; /* unicode is 2 bytes each */
                sec_blob->DomainName.BufferOffset = cpu_to_le32(tmp - *pbuffer);
                sec_blob->DomainName.Length = cpu_to_le16(len);
                sec_blob->DomainName.MaximumLength = cpu_to_le16(len);
                tmp += len;
        }

        if (ses->user_name == NULL) {
                sec_blob->UserName.BufferOffset = cpu_to_le32(tmp - *pbuffer);
                sec_blob->UserName.Length = 0;
                sec_blob->UserName.MaximumLength = 0;
                tmp += 2;
        } else {
                int len;
                len = cifs_strtoUTF16((__le16 *)tmp, ses->user_name,
                                      CIFS_MAX_USERNAME_LEN, nls_cp);
                len *= 2; /* unicode is 2 bytes each */
                sec_blob->UserName.BufferOffset = cpu_to_le32(tmp - *pbuffer);
                sec_blob->UserName.Length = cpu_to_le16(len);
                sec_blob->UserName.MaximumLength = cpu_to_le16(len);
                tmp += len;
        }

        sec_blob->WorkstationName.BufferOffset = cpu_to_le32(tmp - *pbuffer);
        sec_blob->WorkstationName.Length = 0;
        sec_blob->WorkstationName.MaximumLength = 0;
        tmp += 2;

        if (((ses->ntlmssp->server_flags & NTLMSSP_NEGOTIATE_KEY_XCH) ||
                (ses->ntlmssp->server_flags & NTLMSSP_NEGOTIATE_EXTENDED_SEC))
                        && !calc_seckey(ses)) {
                memcpy(tmp, ses->ntlmssp->ciphertext, CIFS_CPHTXT_SIZE);
                sec_blob->SessionKey.BufferOffset = cpu_to_le32(tmp - *pbuffer);
                sec_blob->SessionKey.Length = cpu_to_le16(CIFS_CPHTXT_SIZE);
                sec_blob->SessionKey.MaximumLength =
                                cpu_to_le16(CIFS_CPHTXT_SIZE);
                tmp += CIFS_CPHTXT_SIZE;
        } else {
                sec_blob->SessionKey.BufferOffset = cpu_to_le32(tmp - *pbuffer);
                sec_blob->SessionKey.Length = 0;
                sec_blob->SessionKey.MaximumLength = 0;
        }

        *buflen = tmp - *pbuffer;
setup_ntlmv2_ret:
        return rc;
}

enum securityEnum
cifs_select_sectype(struct TCP_Server_Info *server, enum securityEnum requested)
{
        switch (server->negflavor) {
        case CIFS_NEGFLAVOR_EXTENDED:
                switch (requested) {
                case Kerberos:
                case RawNTLMSSP:
                        return requested;
                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;
                }
        case CIFS_NEGFLAVOR_UNENCAP:
                switch (requested) {
                case NTLM:
                case NTLMv2:
                        return requested;
                case Unspecified:
                        if (global_secflags & CIFSSEC_MAY_NTLMV2)
                                return NTLMv2;
                        if (global_secflags & CIFSSEC_MAY_NTLM)
                                return NTLM;
                default:
                        break;
                }
                /* Fallthrough - to attempt LANMAN authentication next */
        case CIFS_NEGFLAVOR_LANMAN:
                switch (requested) {
                case LANMAN:
                        return requested;
                case Unspecified:
                        if (global_secflags & CIFSSEC_MAY_LANMAN)
                                return LANMAN;
                        /* Fallthrough */
                default:
                        return Unspecified;
                }
        default:
                return Unspecified;
        }
}

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

        /* 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[3];
};

static int
sess_alloc_buffer(struct sess_data *sess_data, int wct)
{
        int rc;
        struct cifs_ses *ses = sess_data->ses;
        struct smb_hdr *smb_buf;

        rc = small_smb_init_no_tc(SMB_COM_SESSION_SETUP_ANDX, wct, ses,
                                  (void **)&smb_buf);

        if (rc)
                return rc;

        sess_data->iov[0].iov_base = (char *)smb_buf;
        sess_data->iov[0].iov_len = be32_to_cpu(smb_buf->smb_buf_length) + 4;
        /*
         * 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;

        /* 2000 big enough to fit max user, domain, NOS name etc. */
        sess_data->iov[2].iov_base = kmalloc(2000, GFP_KERNEL);
        if (!sess_data->iov[2].iov_base) {
                rc = -ENOMEM;
                goto out_free_smb_buf;
        }

        return 0;

out_free_smb_buf:
        kfree(smb_buf);
        sess_data->iov[0].iov_base = NULL;
        sess_data->iov[0].iov_len = 0;
        sess_data->buf0_type = CIFS_NO_BUFFER;
        return rc;
}

static void
sess_free_buffer(struct sess_data *sess_data)
{

        free_rsp_buf(sess_data->buf0_type, sess_data->iov[0].iov_base);
        sess_data->buf0_type = CIFS_NO_BUFFER;
        kfree(sess_data->iov[2].iov_base);
}

static int
sess_establish_session(struct sess_data *sess_data)
{
        struct cifs_ses *ses = sess_data->ses;

        mutex_lock(&ses->server->srv_mutex);
        if (!ses->server->session_estab) {
                if (ses->server->sign) {
                        ses->server->session_key.response =
                                kmemdup(ses->auth_key.response,
                                ses->auth_key.len, GFP_KERNEL);
                        if (!ses->server->session_key.response) {
                                mutex_unlock(&ses->server->srv_mutex);
                                return -ENOMEM;
                        }
                        ses->server->session_key.len =
                                                ses->auth_key.len;
                }
                ses->server->sequence_number = 0x2;
                ses->server->session_estab = true;
        }
        mutex_unlock(&ses->server->srv_mutex);

        cifs_dbg(FYI, "CIFS session established successfully\n");
        spin_lock(&GlobalMid_Lock);
        ses->status = CifsGood;
        ses->need_reconnect = false;
        spin_unlock(&GlobalMid_Lock);

        return 0;
}

static int
sess_sendreceive(struct sess_data *sess_data)
{
        int rc;
        struct smb_hdr *smb_buf = (struct smb_hdr *) sess_data->iov[0].iov_base;
        __u16 count;
        struct kvec rsp_iov = { NULL, 0 };

        count = sess_data->iov[1].iov_len + sess_data->iov[2].iov_len;
        smb_buf->smb_buf_length =
                cpu_to_be32(be32_to_cpu(smb_buf->smb_buf_length) + count);
        put_bcc(count, smb_buf);

        rc = SendReceive2(sess_data->xid, sess_data->ses,
                          sess_data->iov, 3 /* num_iovecs */,
                          &sess_data->buf0_type,
                          CIFS_LOG_ERROR, &rsp_iov);
        cifs_small_buf_release(sess_data->iov[0].iov_base);
        memcpy(&sess_data->iov[0], &rsp_iov, sizeof(struct kvec));

        return rc;
}

/*
 * LANMAN and plaintext are less secure and off by default.
 * So we make this explicitly be turned on in kconfig (in the
 * build) and turned on at runtime (changed from the default)
 * in proc/fs/cifs or via mount parm.  Unfortunately this is
 * needed for old Win (e.g. Win95), some obscure NAS and OS/2
 */
#ifdef CONFIG_CIFS_WEAK_PW_HASH
static void
sess_auth_lanman(struct sess_data *sess_data)
{
        int rc = 0;
        struct smb_hdr *smb_buf;
        SESSION_SETUP_ANDX *pSMB;
        char *bcc_ptr;
        struct cifs_ses *ses = sess_data->ses;
        char lnm_session_key[CIFS_AUTH_RESP_SIZE];
        __u32 capabilities;
        __u16 bytes_remaining;

        /* lanman 2 style sessionsetup */
        /* wct = 10 */
        rc = sess_alloc_buffer(sess_data, 10);
        if (rc)
                goto out;

        pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
        bcc_ptr = sess_data->iov[2].iov_base;
        capabilities = cifs_ssetup_hdr(ses, pSMB);

        pSMB->req.hdr.Flags2 &= ~SMBFLG2_UNICODE;

        if (ses->user_name != NULL) {
                /* no capabilities flags in old lanman negotiation */
                pSMB->old_req.PasswordLength = cpu_to_le16(CIFS_AUTH_RESP_SIZE);

                /* Calculate hash with password and copy into bcc_ptr.
                 * Encryption Key (stored as in cryptkey) gets used if the
                 * security mode bit in Negottiate Protocol response states
                 * to use challenge/response method (i.e. Password bit is 1).
                 */
                rc = calc_lanman_hash(ses->password, ses->server->cryptkey,
                                      ses->server->sec_mode & SECMODE_PW_ENCRYPT ?
                                      true : false, lnm_session_key);
                if (rc)
                        goto out;

                memcpy(bcc_ptr, (char *)lnm_session_key, CIFS_AUTH_RESP_SIZE);
                bcc_ptr += CIFS_AUTH_RESP_SIZE;
        } else {
                pSMB->old_req.PasswordLength = 0;
        }

        /*
         * can not sign if LANMAN negotiated so no need
         * to calculate signing key? but what if server
         * changed to do higher than lanman dialect and
         * we reconnected would we ever calc signing_key?
         */

        cifs_dbg(FYI, "Negotiating LANMAN setting up strings\n");
        /* Unicode not allowed for LANMAN dialects */
        ascii_ssetup_strings(&bcc_ptr, ses, sess_data->nls_cp);

        sess_data->iov[2].iov_len = (long) bcc_ptr -
                        (long) sess_data->iov[2].iov_base;

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

        pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
        smb_buf = (struct smb_hdr *)sess_data->iov[0].iov_base;

        /* lanman response has a word count of 3 */
        if (smb_buf->WordCount != 3) {
                rc = -EIO;
                cifs_dbg(VFS, "bad word count %d\n", smb_buf->WordCount);
                goto out;
        }

        if (le16_to_cpu(pSMB->resp.Action) & GUEST_LOGIN)
                cifs_dbg(FYI, "Guest login\n"); /* BB mark SesInfo struct? */

        ses->Suid = smb_buf->Uid;   /* UID left in wire format (le) */
        cifs_dbg(FYI, "UID = %llu\n", ses->Suid);

        bytes_remaining = get_bcc(smb_buf);
        bcc_ptr = pByteArea(smb_buf);

        /* BB check if Unicode and decode strings */
        if (bytes_remaining == 0) {
                /* no string area to decode, do nothing */
        } else if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
                /* unicode string area must be word-aligned */
                if (((unsigned long) bcc_ptr - (unsigned long) smb_buf) % 2) {
                        ++bcc_ptr;
                        --bytes_remaining;
                }
                decode_unicode_ssetup(&bcc_ptr, bytes_remaining, ses,
                                      sess_data->nls_cp);
        } else {
                decode_ascii_ssetup(&bcc_ptr, bytes_remaining, ses,
                                    sess_data->nls_cp);
        }

        rc = sess_establish_session(sess_data);
out:
        sess_data->result = rc;
        sess_data->func = NULL;
        sess_free_buffer(sess_data);
}

#endif

static void
sess_auth_ntlm(struct sess_data *sess_data)
{
        int rc = 0;
        struct smb_hdr *smb_buf;
        SESSION_SETUP_ANDX *pSMB;
        char *bcc_ptr;
        struct cifs_ses *ses = sess_data->ses;
        __u32 capabilities;
        __u16 bytes_remaining;

        /* old style NTLM sessionsetup */
        /* wct = 13 */
        rc = sess_alloc_buffer(sess_data, 13);
        if (rc)
                goto out;

        pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
        bcc_ptr = sess_data->iov[2].iov_base;
        capabilities = cifs_ssetup_hdr(ses, pSMB);

        pSMB->req_no_secext.Capabilities = cpu_to_le32(capabilities);
        if (ses->user_name != NULL) {
                pSMB->req_no_secext.CaseInsensitivePasswordLength =
                                cpu_to_le16(CIFS_AUTH_RESP_SIZE);
                pSMB->req_no_secext.CaseSensitivePasswordLength =
                                cpu_to_le16(CIFS_AUTH_RESP_SIZE);

                /* calculate ntlm response and session key */
                rc = setup_ntlm_response(ses, sess_data->nls_cp);
                if (rc) {
                        cifs_dbg(VFS, "Error %d during NTLM authentication\n",
                                         rc);
                        goto out;
                }

                /* copy ntlm response */
                memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
                                CIFS_AUTH_RESP_SIZE);
                bcc_ptr += CIFS_AUTH_RESP_SIZE;
                memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
                                CIFS_AUTH_RESP_SIZE);
                bcc_ptr += CIFS_AUTH_RESP_SIZE;
        } else {
                pSMB->req_no_secext.CaseInsensitivePasswordLength = 0;
                pSMB->req_no_secext.CaseSensitivePasswordLength = 0;
        }

        if (ses->capabilities & CAP_UNICODE) {
                /* unicode strings must be word aligned */
                if (sess_data->iov[0].iov_len % 2) {
                        *bcc_ptr = 0;
                        bcc_ptr++;
                }
                unicode_ssetup_strings(&bcc_ptr, ses, sess_data->nls_cp);
        } else {
                ascii_ssetup_strings(&bcc_ptr, ses, sess_data->nls_cp);
        }


        sess_data->iov[2].iov_len = (long) bcc_ptr -
                        (long) sess_data->iov[2].iov_base;

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

        pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
        smb_buf = (struct smb_hdr *)sess_data->iov[0].iov_base;

        if (smb_buf->WordCount != 3) {
                rc = -EIO;
                cifs_dbg(VFS, "bad word count %d\n", smb_buf->WordCount);
                goto out;
        }

        if (le16_to_cpu(pSMB->resp.Action) & GUEST_LOGIN)
                cifs_dbg(FYI, "Guest login\n"); /* BB mark SesInfo struct? */

        ses->Suid = smb_buf->Uid;   /* UID left in wire format (le) */
        cifs_dbg(FYI, "UID = %llu\n", ses->Suid);

        bytes_remaining = get_bcc(smb_buf);
        bcc_ptr = pByteArea(smb_buf);

        /* BB check if Unicode and decode strings */
        if (bytes_remaining == 0) {
                /* no string area to decode, do nothing */
        } else if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
                /* unicode string area must be word-aligned */
                if (((unsigned long) bcc_ptr - (unsigned long) smb_buf) % 2) {
                        ++bcc_ptr;
                        --bytes_remaining;
                }
                decode_unicode_ssetup(&bcc_ptr, bytes_remaining, ses,
                                      sess_data->nls_cp);
        } else {
                decode_ascii_ssetup(&bcc_ptr, bytes_remaining, ses,
                                    sess_data->nls_cp);
        }

        rc = sess_establish_session(sess_data);
out:
        sess_data->result = rc;
        sess_data->func = NULL;
        sess_free_buffer(sess_data);
        kfree(ses->auth_key.response);
        ses->auth_key.response = NULL;
}

static void
sess_auth_ntlmv2(struct sess_data *sess_data)
{
        int rc = 0;
        struct smb_hdr *smb_buf;
        SESSION_SETUP_ANDX *pSMB;
        char *bcc_ptr;
        struct cifs_ses *ses = sess_data->ses;
        __u32 capabilities;
        __u16 bytes_remaining;

        /* old style NTLM sessionsetup */
        /* wct = 13 */
        rc = sess_alloc_buffer(sess_data, 13);
        if (rc)
                goto out;

        pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
        bcc_ptr = sess_data->iov[2].iov_base;
        capabilities = cifs_ssetup_hdr(ses, pSMB);

        pSMB->req_no_secext.Capabilities = cpu_to_le32(capabilities);

        /* LM2 password would be here if we supported it */
        pSMB->req_no_secext.CaseInsensitivePasswordLength = 0;

        if (ses->user_name != NULL) {
                /* calculate nlmv2 response and session key */
                rc = setup_ntlmv2_rsp(ses, sess_data->nls_cp);
                if (rc) {
                        cifs_dbg(VFS, "Error %d during NTLMv2 authentication\n", rc);
                        goto out;
                }

                memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
                                ses->auth_key.len - CIFS_SESS_KEY_SIZE);
                bcc_ptr += ses->auth_key.len - CIFS_SESS_KEY_SIZE;

                /* set case sensitive password length after tilen may get
                 * assigned, tilen is 0 otherwise.
                 */
                pSMB->req_no_secext.CaseSensitivePasswordLength =
                        cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
        } else {
                pSMB->req_no_secext.CaseSensitivePasswordLength = 0;
        }

        if (ses->capabilities & CAP_UNICODE) {
                if (sess_data->iov[0].iov_len % 2) {
                        *bcc_ptr = 0;
                        bcc_ptr++;
                }
                unicode_ssetup_strings(&bcc_ptr, ses, sess_data->nls_cp);
        } else {
                ascii_ssetup_strings(&bcc_ptr, ses, sess_data->nls_cp);
        }


        sess_data->iov[2].iov_len = (long) bcc_ptr -
                        (long) sess_data->iov[2].iov_base;

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

        pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
        smb_buf = (struct smb_hdr *)sess_data->iov[0].iov_base;

        if (smb_buf->WordCount != 3) {
                rc = -EIO;
                cifs_dbg(VFS, "bad word count %d\n", smb_buf->WordCount);
                goto out;
        }

        if (le16_to_cpu(pSMB->resp.Action) & GUEST_LOGIN)
                cifs_dbg(FYI, "Guest login\n"); /* BB mark SesInfo struct? */

        ses->Suid = smb_buf->Uid;   /* UID left in wire format (le) */
        cifs_dbg(FYI, "UID = %llu\n", ses->Suid);

        bytes_remaining = get_bcc(smb_buf);
        bcc_ptr = pByteArea(smb_buf);

        /* BB check if Unicode and decode strings */
        if (bytes_remaining == 0) {
                /* no string area to decode, do nothing */
        } else if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
                /* unicode string area must be word-aligned */
                if (((unsigned long) bcc_ptr - (unsigned long) smb_buf) % 2) {
                        ++bcc_ptr;
                        --bytes_remaining;
                }
                decode_unicode_ssetup(&bcc_ptr, bytes_remaining, ses,
                                      sess_data->nls_cp);
        } else {
                decode_ascii_ssetup(&bcc_ptr, bytes_remaining, ses,
                                    sess_data->nls_cp);
        }

        rc = sess_establish_session(sess_data);
out:
        sess_data->result = rc;
        sess_data->func = NULL;
        sess_free_buffer(sess_data);
        kfree(ses->auth_key.response);
        ses->auth_key.response = NULL;
}

#ifdef CONFIG_CIFS_UPCALL
static void
sess_auth_kerberos(struct sess_data *sess_data)
{
        int rc = 0;
        struct smb_hdr *smb_buf;
        SESSION_SETUP_ANDX *pSMB;
        char *bcc_ptr;
        struct cifs_ses *ses = sess_data->ses;
        __u32 capabilities;
        __u16 bytes_remaining;
        struct key *spnego_key = NULL;
        struct cifs_spnego_msg *msg;
        u16 blob_len;

        /* extended security */
        /* wct = 12 */
        rc = sess_alloc_buffer(sess_data, 12);
        if (rc)
                goto out;

        pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
        bcc_ptr = sess_data->iov[2].iov_base;
        capabilities = cifs_ssetup_hdr(ses, pSMB);

        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,
                  "incorrect version of cifs.upcall (expected %d but got %d)",
                              CIFS_SPNEGO_UPCALL_VERSION, msg->version);
                rc = -EKEYREJECTED;
                goto out_put_spnego_key;
        }

        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;

        pSMB->req.hdr.Flags2 |= SMBFLG2_EXT_SEC;
        capabilities |= CAP_EXTENDED_SECURITY;
        pSMB->req.Capabilities = cpu_to_le32(capabilities);
        sess_data->iov[1].iov_base = msg->data + msg->sesskey_len;
        sess_data->iov[1].iov_len = msg->secblob_len;
        pSMB->req.SecurityBlobLength = cpu_to_le16(sess_data->iov[1].iov_len);

        if (ses->capabilities & CAP_UNICODE) {
                /* unicode strings must be word aligned */
                if ((sess_data->iov[0].iov_len
                        + sess_data->iov[1].iov_len) % 2) {
                        *bcc_ptr = 0;
                        bcc_ptr++;
                }
                unicode_oslm_strings(&bcc_ptr, sess_data->nls_cp);
                unicode_domain_string(&bcc_ptr, ses, sess_data->nls_cp);
        } else {
                /* BB: is this right? */
                ascii_ssetup_strings(&bcc_ptr, ses, sess_data->nls_cp);
        }

        sess_data->iov[2].iov_len = (long) bcc_ptr -
                        (long) sess_data->iov[2].iov_base;

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

        pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
        smb_buf = (struct smb_hdr *)sess_data->iov[0].iov_base;

        if (smb_buf->WordCount != 4) {
                rc = -EIO;
                cifs_dbg(VFS, "bad word count %d\n", smb_buf->WordCount);
                goto out_put_spnego_key;
        }

        if (le16_to_cpu(pSMB->resp.Action) & GUEST_LOGIN)
                cifs_dbg(FYI, "Guest login\n"); /* BB mark SesInfo struct? */

        ses->Suid = smb_buf->Uid;   /* UID left in wire format (le) */
        cifs_dbg(FYI, "UID = %llu\n", ses->Suid);

        bytes_remaining = get_bcc(smb_buf);
        bcc_ptr = pByteArea(smb_buf);

        blob_len = le16_to_cpu(pSMB->resp.SecurityBlobLength);
        if (blob_len > bytes_remaining) {
                cifs_dbg(VFS, "bad security blob length %d\n",
                                blob_len);
                rc = -EINVAL;
                goto out_put_spnego_key;
        }
        bcc_ptr += blob_len;
        bytes_remaining -= blob_len;

        /* BB check if Unicode and decode strings */
        if (bytes_remaining == 0) {
                /* no string area to decode, do nothing */
        } else if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
                /* unicode string area must be word-aligned */
                if (((unsigned long) bcc_ptr - (unsigned long) smb_buf) % 2) {
                        ++bcc_ptr;
                        --bytes_remaining;
                }
                decode_unicode_ssetup(&bcc_ptr, bytes_remaining, ses,
                                      sess_data->nls_cp);
        } else {
                decode_ascii_ssetup(&bcc_ptr, bytes_remaining, ses,
                                    sess_data->nls_cp);
        }

        rc = 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;
        sess_free_buffer(sess_data);
        kfree(ses->auth_key.response);
        ses->auth_key.response = NULL;
}

#endif /* ! CONFIG_CIFS_UPCALL */

/*
 * The required kvec buffers have to be allocated before calling this
 * function.
 */
static int
_sess_auth_rawntlmssp_assemble_req(struct sess_data *sess_data)
{
        SESSION_SETUP_ANDX *pSMB;
        struct cifs_ses *ses = sess_data->ses;
        __u32 capabilities;
        char *bcc_ptr;

        pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;

        capabilities = cifs_ssetup_hdr(ses, pSMB);
        if ((pSMB->req.hdr.Flags2 & SMBFLG2_UNICODE) == 0) {
                cifs_dbg(VFS, "NTLMSSP requires Unicode support\n");
                return -ENOSYS;
        }

        pSMB->req.hdr.Flags2 |= SMBFLG2_EXT_SEC;
        capabilities |= CAP_EXTENDED_SECURITY;
        pSMB->req.Capabilities |= cpu_to_le32(capabilities);

        bcc_ptr = sess_data->iov[2].iov_base;
        /* unicode strings must be word aligned */
        if ((sess_data->iov[0].iov_len + sess_data->iov[1].iov_len) % 2) {
                *bcc_ptr = 0;
                bcc_ptr++;
        }
        unicode_oslm_strings(&bcc_ptr, sess_data->nls_cp);

        sess_data->iov[2].iov_len = (long) bcc_ptr -
                                        (long) sess_data->iov[2].iov_base;

        return 0;
}

static void
sess_auth_rawntlmssp_authenticate(struct sess_data *sess_data);

static void
sess_auth_rawntlmssp_negotiate(struct sess_data *sess_data)
{
        int rc;
        struct smb_hdr *smb_buf;
        SESSION_SETUP_ANDX *pSMB;
        struct cifs_ses *ses = sess_data->ses;
        __u16 bytes_remaining;
        char *bcc_ptr;
        u16 blob_len;

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

        /*
         * 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;
        }
        ses->ntlmssp->sesskey_per_smbsess = false;

        /* wct = 12 */
        rc = sess_alloc_buffer(sess_data, 12);
        if (rc)
                goto out;

        pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;

        /* Build security blob before we assemble the request */
        build_ntlmssp_negotiate_blob(pSMB->req.SecurityBlob, ses);
        sess_data->iov[1].iov_len = sizeof(NEGOTIATE_MESSAGE);
        sess_data->iov[1].iov_base = pSMB->req.SecurityBlob;
        pSMB->req.SecurityBlobLength = cpu_to_le16(sizeof(NEGOTIATE_MESSAGE));

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

        rc = sess_sendreceive(sess_data);

        pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
        smb_buf = (struct smb_hdr *)sess_data->iov[0].iov_base;

        /* If true, rc here is expected and not an error */
        if (sess_data->buf0_type != CIFS_NO_BUFFER &&
            smb_buf->Status.CifsError ==
                        cpu_to_le32(NT_STATUS_MORE_PROCESSING_REQUIRED))
                rc = 0;

        if (rc)
                goto out;

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

        if (smb_buf->WordCount != 4) {
                rc = -EIO;
                cifs_dbg(VFS, "bad word count %d\n", smb_buf->WordCount);
                goto out;
        }

        ses->Suid = smb_buf->Uid;   /* UID left in wire format (le) */
        cifs_dbg(FYI, "UID = %llu\n", ses->Suid);

        bytes_remaining = get_bcc(smb_buf);
        bcc_ptr = pByteArea(smb_buf);

        blob_len = le16_to_cpu(pSMB->resp.SecurityBlobLength);
        if (blob_len > bytes_remaining) {
                cifs_dbg(VFS, "bad security blob length %d\n",
                                blob_len);
                rc = -EINVAL;
                goto out;
        }

        rc = decode_ntlmssp_challenge(bcc_ptr, blob_len, ses);
out:
        sess_free_buffer(sess_data);

        if (!rc) {
                sess_data->func = sess_auth_rawntlmssp_authenticate;
                return;
        }

        /* Else error. Cleanup */
        kfree(ses->auth_key.response);
        ses->auth_key.response = NULL;
        kfree(ses->ntlmssp);
        ses->ntlmssp = NULL;

        sess_data->func = NULL;
        sess_data->result = rc;
}

static void
sess_auth_rawntlmssp_authenticate(struct sess_data *sess_data)
{
        int rc;
        struct smb_hdr *smb_buf;
        SESSION_SETUP_ANDX *pSMB;
        struct cifs_ses *ses = sess_data->ses;
        __u16 bytes_remaining;
        char *bcc_ptr;
        unsigned char *ntlmsspblob = NULL;
        u16 blob_len;

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

        /* wct = 12 */
        rc = sess_alloc_buffer(sess_data, 12);
        if (rc)
                goto out;

        /* Build security blob before we assemble the request */
        pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
        smb_buf = (struct smb_hdr *)pSMB;
        rc = build_ntlmssp_auth_blob(&ntlmsspblob,
                                        &blob_len, ses, sess_data->nls_cp);
        if (rc)
                goto out_free_ntlmsspblob;
        sess_data->iov[1].iov_len = blob_len;
        sess_data->iov[1].iov_base = ntlmsspblob;
        pSMB->req.SecurityBlobLength = cpu_to_le16(blob_len);
        /*
         * Make sure that we tell the server that we are using
         * the uid that it just gave us back on the response
         * (challenge)
         */
        smb_buf->Uid = ses->Suid;

        rc = _sess_auth_rawntlmssp_assemble_req(sess_data);
        if (rc)
                goto out_free_ntlmsspblob;

        rc = sess_sendreceive(sess_data);
        if (rc)
                goto out_free_ntlmsspblob;

        pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
        smb_buf = (struct smb_hdr *)sess_data->iov[0].iov_base;
        if (smb_buf->WordCount != 4) {
                rc = -EIO;
                cifs_dbg(VFS, "bad word count %d\n", smb_buf->WordCount);
                goto out_free_ntlmsspblob;
        }

        if (le16_to_cpu(pSMB->resp.Action) & GUEST_LOGIN)
                cifs_dbg(FYI, "Guest login\n"); /* BB mark SesInfo struct? */

        if (ses->Suid != smb_buf->Uid) {
                ses->Suid = smb_buf->Uid;
                cifs_dbg(FYI, "UID changed! new UID = %llu\n", ses->Suid);
        }

        bytes_remaining = get_bcc(smb_buf);
        bcc_ptr = pByteArea(smb_buf);
        blob_len = le16_to_cpu(pSMB->resp.SecurityBlobLength);
        if (blob_len > bytes_remaining) {
                cifs_dbg(VFS, "bad security blob length %d\n",
                                blob_len);
                rc = -EINVAL;
                goto out_free_ntlmsspblob;
        }
        bcc_ptr += blob_len;
        bytes_remaining -= blob_len;


        /* BB check if Unicode and decode strings */
        if (bytes_remaining == 0) {
                /* no string area to decode, do nothing */
        } else if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
                /* unicode string area must be word-aligned */
                if (((unsigned long) bcc_ptr - (unsigned long) smb_buf) % 2) {
                        ++bcc_ptr;
                        --bytes_remaining;
                }
                decode_unicode_ssetup(&bcc_ptr, bytes_remaining, ses,
                                      sess_data->nls_cp);
        } else {
                decode_ascii_ssetup(&bcc_ptr, bytes_remaining, ses,
                                    sess_data->nls_cp);
        }

out_free_ntlmsspblob:
        kfree(ntlmsspblob);
out:
        sess_free_buffer(sess_data);

         if (!rc)
                rc = sess_establish_session(sess_data);

        /* Cleanup */
        kfree(ses->auth_key.response);
        ses->auth_key.response = NULL;
        kfree(ses->ntlmssp);
        ses->ntlmssp = NULL;

        sess_data->func = NULL;
        sess_data->result = rc;
}

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

        type = cifs_select_sectype(ses->server, 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 LANMAN:
                /* LANMAN and plaintext are less secure and off by default.
                 * So we make this explicitly be turned on in kconfig (in the
                 * build) and turned on at runtime (changed from the default)
                 * in proc/fs/cifs or via mount parm.  Unfortunately this is
                 * needed for old Win (e.g. Win95), some obscure NAS and OS/2 */
#ifdef CONFIG_CIFS_WEAK_PW_HASH
                sess_data->func = sess_auth_lanman;
                break;
#else
                return -EOPNOTSUPP;
#endif
        case NTLM:
                sess_data->func = sess_auth_ntlm;
                break;
        case NTLMv2:
                sess_data->func = sess_auth_ntlmv2;
                break;
        case Kerberos:
#ifdef CONFIG_CIFS_UPCALL
                sess_data->func = sess_auth_kerberos;
                break;
#else
                cifs_dbg(VFS, "Kerberos negotiated but upcall support disabled!\n");
                return -ENOSYS;
                break;
#endif /* CONFIG_CIFS_UPCALL */
        case RawNTLMSSP:
                sess_data->func = sess_auth_rawntlmssp_negotiate;
                break;
        default:
                cifs_dbg(VFS, "secType %d not supported!\n", type);
                return -ENOSYS;
        }

        return 0;
}

int CIFS_SessSetup(const unsigned int xid, struct cifs_ses *ses,
                    const struct nls_table *nls_cp)
{
        int rc = 0;
        struct sess_data *sess_data;

        if (ses == NULL) {
                WARN(1, "%s: ses == NULL!", __func__);
                return -EINVAL;
        }

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

        rc = 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;

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

        /* Store result before we free sess_data */
        rc = sess_data->result;

out:
        kfree(sess_data);
        return rc;
}