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 = __constant_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;
	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;
}

/* We do not malloc the blob, it is passed in pbuffer, because its
   maximum possible size is fixed and small, making this approach cleaner.
   This function returns the length of the data in the blob */
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 = (AUTHENTICATE_MESSAGE *)pbuffer;
	__u32 flags;
	unsigned char *tmp;

	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;
	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);
	rc = setup_ntlmv2_rsp(ses, nls_cp);
	if (rc) {
		cifs_dbg(VFS, "Error %d during NTLMSSP authentication\n", rc);
		goto setup_ntlmv2_ret;
	}
	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);

	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_USERNAME_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;
	}

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

enum securityEnum
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:
			/* Fallthrough to attempt LANMAN authentication next */
			break;
		}
	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;

	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);

	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;

	/* 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);

	memcpy(bcc_ptr, (char *)lnm_session_key, CIFS_AUTH_RESP_SIZE);
	bcc_ptr += CIFS_AUTH_RESP_SIZE;

	/*
	 * 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);
}

#else

static void
sess_auth_lanman(struct sess_data *sess_data)
{
	sess_data->result = -EOPNOTSUPP;
	sess_data->func = NULL;
}
#endif

int
CIFS_SessSetup(const unsigned int xid, struct cifs_ses *ses,
	       const struct nls_table *nls_cp)
{
	int rc = 0;
	int wct;
	struct smb_hdr *smb_buf;
	char *bcc_ptr;
	char *str_area;
	SESSION_SETUP_ANDX *pSMB;
	__u32 capabilities;
	__u16 count;
	int resp_buf_type;
	struct kvec iov[3];
	enum securityEnum type;
	__u16 action, bytes_remaining;
	struct key *spnego_key = NULL;
	__le32 phase = NtLmNegotiate; /* NTLMSSP, if needed, is multistage */
	u16 blob_len;
	char *ntlmsspblob = NULL;
	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;
	sess_data->xid = xid;
	sess_data->ses = ses;
	sess_data->buf0_type = CIFS_NO_BUFFER;
	sess_data->nls_cp = (struct nls_table *) nls_cp;

	type = 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:
		sess_auth_lanman(sess_data);
		goto out;
	default:
		cifs_dbg(FYI, "Continuing with CIFS_SessSetup\n");
	}

	if (type == RawNTLMSSP) {
		/* if memory allocation is successful, caller of this function
		 * frees it.
		 */
		ses->ntlmssp = kmalloc(sizeof(struct ntlmssp_auth), GFP_KERNEL);
		if (!ses->ntlmssp)
			return -ENOMEM;
		ses->ntlmssp->sesskey_per_smbsess = false;

	}

ssetup_ntlmssp_authenticate:
	if (phase == NtLmChallenge)
		phase = NtLmAuthenticate; /* if ntlmssp, now final phase */

	if ((type == NTLM) || (type == NTLMv2)) {
		/* For NTLMv2 failures eventually may need to retry NTLM */
		wct = 13; /* old style NTLM sessionsetup */
	} else /* same size: negotiate or auth, NTLMSSP or extended security */
		wct = 12;

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

	pSMB = (SESSION_SETUP_ANDX *)smb_buf;

	capabilities = cifs_ssetup_hdr(ses, pSMB);

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

	/* setting this here allows the code at the end of the function
	   to free the request buffer if there's an error */
	resp_buf_type = CIFS_SMALL_BUFFER;

	/* 2000 big enough to fit max user, domain, NOS name etc. */
	str_area = kmalloc(2000, GFP_KERNEL);
	if (str_area == NULL) {
		rc = -ENOMEM;
		goto ssetup_exit;
	}
	bcc_ptr = str_area;

	iov[1].iov_base = NULL;
	iov[1].iov_len = 0;

	if (type == NTLM) {
		pSMB->req_no_secext.Capabilities = cpu_to_le32(capabilities);
		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, nls_cp);
		if (rc) {
			cifs_dbg(VFS, "Error %d during NTLM authentication\n",
				 rc);
			goto ssetup_exit;
		}

		/* 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;

		if (ses->capabilities & CAP_UNICODE) {
			/* unicode strings must be word aligned */
			if (iov[0].iov_len % 2) {
				*bcc_ptr = 0;
				bcc_ptr++;
			}
			unicode_ssetup_strings(&bcc_ptr, ses, nls_cp);
		} else
			ascii_ssetup_strings(&bcc_ptr, ses, nls_cp);
	} else if (type == NTLMv2) {
		pSMB->req_no_secext.Capabilities = cpu_to_le32(capabilities);

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

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

		if (ses->capabilities & CAP_UNICODE) {
			if (iov[0].iov_len % 2) {
				*bcc_ptr = 0;
				bcc_ptr++;
			}
			unicode_ssetup_strings(&bcc_ptr, ses, nls_cp);
		} else
			ascii_ssetup_strings(&bcc_ptr, ses, nls_cp);
	} else if (type == Kerberos) {
#ifdef CONFIG_CIFS_UPCALL
		struct cifs_spnego_msg *msg;

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

		msg = spnego_key->payload.data;
		/* 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 ssetup_exit;
		}

		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 ssetup_exit;
		}
		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);
		iov[1].iov_base = msg->data + msg->sesskey_len;
		iov[1].iov_len = msg->secblob_len;
		pSMB->req.SecurityBlobLength = cpu_to_le16(iov[1].iov_len);

		if (ses->capabilities & CAP_UNICODE) {
			/* unicode strings must be word aligned */
			if ((iov[0].iov_len + iov[1].iov_len) % 2) {
				*bcc_ptr = 0;
				bcc_ptr++;
			}
			unicode_oslm_strings(&bcc_ptr, nls_cp);
			unicode_domain_string(&bcc_ptr, ses, nls_cp);
		} else
		/* BB: is this right? */
			ascii_ssetup_strings(&bcc_ptr, ses, nls_cp);
#else /* ! CONFIG_CIFS_UPCALL */
		cifs_dbg(VFS, "Kerberos negotiated but upcall support disabled!\n");
		rc = -ENOSYS;
		goto ssetup_exit;
#endif /* CONFIG_CIFS_UPCALL */
	} else if (type == RawNTLMSSP) {
		if ((pSMB->req.hdr.Flags2 & SMBFLG2_UNICODE) == 0) {
			cifs_dbg(VFS, "NTLMSSP requires Unicode support\n");
			rc = -ENOSYS;
			goto ssetup_exit;
		}

		cifs_dbg(FYI, "ntlmssp session setup phase %d\n", phase);
		pSMB->req.hdr.Flags2 |= SMBFLG2_EXT_SEC;
		capabilities |= CAP_EXTENDED_SECURITY;
		pSMB->req.Capabilities |= cpu_to_le32(capabilities);
		switch(phase) {
		case NtLmNegotiate:
			build_ntlmssp_negotiate_blob(
				pSMB->req.SecurityBlob, ses);
			iov[1].iov_len = sizeof(NEGOTIATE_MESSAGE);
			iov[1].iov_base = pSMB->req.SecurityBlob;
			pSMB->req.SecurityBlobLength =
				cpu_to_le16(sizeof(NEGOTIATE_MESSAGE));
			break;
		case NtLmAuthenticate:
			/*
			 * 5 is an empirical value, large enough to hold
			 * authenticate message plus max 10 of av paris,
			 * domain, user, workstation names, flags, etc.
			 */
			ntlmsspblob = kzalloc(
				5*sizeof(struct _AUTHENTICATE_MESSAGE),
				GFP_KERNEL);
			if (!ntlmsspblob) {
				rc = -ENOMEM;
				goto ssetup_exit;
			}

			rc = build_ntlmssp_auth_blob(ntlmsspblob,
						&blob_len, ses, nls_cp);
			if (rc)
				goto ssetup_exit;
			iov[1].iov_len = blob_len;
			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;
			break;
		default:
			cifs_dbg(VFS, "invalid phase %d\n", phase);
			rc = -ENOSYS;
			goto ssetup_exit;
		}
		/* unicode strings must be word aligned */
		if ((iov[0].iov_len + iov[1].iov_len) % 2) {
			*bcc_ptr = 0;
			bcc_ptr++;
		}
		unicode_oslm_strings(&bcc_ptr, nls_cp);
	} else {
		cifs_dbg(VFS, "secType %d not supported!\n", type);
		rc = -ENOSYS;
		goto ssetup_exit;
	}

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

	count = iov[1].iov_len + 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(xid, ses, iov, 3 /* num_iovecs */, &resp_buf_type,
			  CIFS_LOG_ERROR);
	/* SMB request buf freed in SendReceive2 */

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

	if ((type == RawNTLMSSP) && (resp_buf_type != CIFS_NO_BUFFER) &&
	    (smb_buf->Status.CifsError ==
			cpu_to_le32(NT_STATUS_MORE_PROCESSING_REQUIRED))) {
		if (phase != NtLmNegotiate) {
			cifs_dbg(VFS, "Unexpected more processing error\n");
			goto ssetup_exit;
		}
		/* NTLMSSP Negotiate sent now processing challenge (response) */
		phase = NtLmChallenge; /* process ntlmssp challenge */
		rc = 0; /* MORE_PROC rc is not an error here, but expected */
	}
	if (rc)
		goto ssetup_exit;

	if ((smb_buf->WordCount != 3) && (smb_buf->WordCount != 4)) {
		rc = -EIO;
		cifs_dbg(VFS, "bad word count %d\n", smb_buf->WordCount);
		goto ssetup_exit;
	}
	action = le16_to_cpu(pSMB->resp.Action);
	if (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);
	/* response can have either 3 or 4 word count - Samba sends 3 */
	/* and lanman response is 3 */
	bytes_remaining = get_bcc(smb_buf);
	bcc_ptr = pByteArea(smb_buf);

	if (smb_buf->WordCount == 4) {
		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 ssetup_exit;
		}
		if (phase == NtLmChallenge) {
			rc = decode_ntlmssp_challenge(bcc_ptr, blob_len, ses);
			if (rc)
				goto ssetup_exit;
		}
		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, nls_cp);
	} else {
		decode_ascii_ssetup(&bcc_ptr, bytes_remaining, ses, nls_cp);
	}

ssetup_exit:
	if (spnego_key) {
		key_invalidate(spnego_key);
		key_put(spnego_key);
	}
	kfree(str_area);
	kfree(ntlmsspblob);
	ntlmsspblob = NULL;
	if (resp_buf_type == CIFS_SMALL_BUFFER) {
		cifs_dbg(FYI, "ssetup freeing small buf %p\n", iov[0].iov_base);
		cifs_small_buf_release(iov[0].iov_base);
	} else if (resp_buf_type == CIFS_LARGE_BUFFER)
		cifs_buf_release(iov[0].iov_base);

	/* if ntlmssp, and negotiate succeeded, proceed to authenticate phase */
	if ((phase == NtLmChallenge) && (rc == 0))
		goto ssetup_ntlmssp_authenticate;

	if (!rc) {
		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) {
					rc = -ENOMEM;
					mutex_unlock(&ses->server->srv_mutex);
					goto keycp_exit;
				}
				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);
	}

keycp_exit:
	kfree(ses->auth_key.response);
	ses->auth_key.response = NULL;
	kfree(ses->ntlmssp);

	return rc;

out:
	rc = sess_data->result;
	kfree(sess_data);
	return rc;
}