fs/cifs/cifsencrypt.c - kernel/msm-4.19 - Gitiles

 /*
  *   fs/cifs/cifsencrypt.c
  *
  *   Copyright (C) International Business Machines  Corp., 2005,2006
  *   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 <linux/fs.h>
 #include <linux/slab.h>
 #include "cifspdu.h"
 #include "cifsglob.h"
 #include "cifs_debug.h"
 #include "md5.h"
 #include "cifs_unicode.h"
 #include "cifsproto.h"
 #include "ntlmssp.h"
 #include <linux/ctype.h>
 #include <linux/random.h>

 /* Calculate and return the CIFS signature based on the mac key and SMB PDU */
 /* the 16 byte signature must be allocated by the caller  */
 /* Note we only use the 1st eight bytes */
 /* Note that the smb header signature field on input contains the
 	sequence number before this function is called */

 extern void mdfour(unsigned char *out, unsigned char *in, int n);
 extern void E_md4hash(const unsigned char *passwd, unsigned char *p16);
 extern void SMBencrypt(unsigned char *passwd, const unsigned char *c8,
 		       unsigned char *p24);

 static int cifs_calculate_signature(const struct smb_hdr *cifs_pdu,
 				const struct session_key *key, char *signature)
 {
 	struct	MD5Context context;

 	if ((cifs_pdu == NULL) || (signature == NULL) || (key == NULL))
 		return -EINVAL;

 	cifs_MD5_init(&context);
 	cifs_MD5_update(&context, (char *)&key->data, key->len);
 	cifs_MD5_update(&context, cifs_pdu->Protocol, cifs_pdu->smb_buf_length);

 	cifs_MD5_final(signature, &context);
 	return 0;
 }

 int cifs_sign_smb(struct smb_hdr *cifs_pdu, struct TCP_Server_Info *server,
 		  __u32 *pexpected_response_sequence_number)
 {
 	int rc = 0;
 	char smb_signature[20];

 	if ((cifs_pdu == NULL) || (server == NULL))
 		return -EINVAL;

 	if ((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
 		return rc;

 	spin_lock(&GlobalMid_Lock);
 	cifs_pdu->Signature.Sequence.SequenceNumber =
 			cpu_to_le32(server->sequence_number);
 	cifs_pdu->Signature.Sequence.Reserved = 0;

 	*pexpected_response_sequence_number = server->sequence_number++;
 	server->sequence_number++;
 	spin_unlock(&GlobalMid_Lock);

 	rc = cifs_calculate_signature(cifs_pdu, &server->session_key,
 				      smb_signature);
 	if (rc)
 		memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
 	else
 		memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);

 	return rc;
 }

 static int cifs_calc_signature2(const struct kvec *iov, int n_vec,
 				const struct session_key *key, char *signature)
 {
 	struct  MD5Context context;
 	int i;

 	if ((iov == NULL) || (signature == NULL) || (key == NULL))
 		return -EINVAL;

 	cifs_MD5_init(&context);
 	cifs_MD5_update(&context, (char *)&key->data, key->len);
 	for (i = 0; i < n_vec; i++) {
 		if (iov[i].iov_len == 0)
 			continue;
 		if (iov[i].iov_base == NULL) {
 			cERROR(1, "null iovec entry");
 			return -EIO;
 		}
 		/* The first entry includes a length field (which does not get
 		   signed that occupies the first 4 bytes before the header */
 		if (i == 0) {
 			if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
 				break; /* nothing to sign or corrupt header */
 			cifs_MD5_update(&context, iov[0].iov_base+4,
 				  iov[0].iov_len-4);
 		} else
 			cifs_MD5_update(&context, iov[i].iov_base, iov[i].iov_len);
 	}

 	cifs_MD5_final(signature, &context);

 	return 0;
 }


 int cifs_sign_smb2(struct kvec *iov, int n_vec, struct TCP_Server_Info *server,
 		   __u32 *pexpected_response_sequence_number)
 {
 	int rc = 0;
 	char smb_signature[20];
 	struct smb_hdr *cifs_pdu = iov[0].iov_base;

 	if ((cifs_pdu == NULL) || (server == NULL))
 		return -EINVAL;

 	if ((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
 		return rc;

 	spin_lock(&GlobalMid_Lock);
 	cifs_pdu->Signature.Sequence.SequenceNumber =
 				cpu_to_le32(server->sequence_number);
 	cifs_pdu->Signature.Sequence.Reserved = 0;

 	*pexpected_response_sequence_number = server->sequence_number++;
 	server->sequence_number++;
 	spin_unlock(&GlobalMid_Lock);

 	rc = cifs_calc_signature2(iov, n_vec, &server->session_key,
 				      smb_signature);
 	if (rc)
 		memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
 	else
 		memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);

 	return rc;
 }

 int cifs_verify_signature(struct smb_hdr *cifs_pdu,
 			  const struct session_key *session_key,
 			  __u32 expected_sequence_number)
 {
 	unsigned int rc;
 	char server_response_sig[8];
 	char what_we_think_sig_should_be[20];

 	if (cifs_pdu == NULL || session_key == NULL)
 		return -EINVAL;

 	if (cifs_pdu->Command == SMB_COM_NEGOTIATE)
 		return 0;

 	if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) {
 		struct smb_com_lock_req *pSMB =
 			(struct smb_com_lock_req *)cifs_pdu;
 	    if (pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE)
 			return 0;
 	}

 	/* BB what if signatures are supposed to be on for session but
 	   server does not send one? BB */

 	/* Do not need to verify session setups with signature "BSRSPYL "  */
 	if (memcmp(cifs_pdu->Signature.SecuritySignature, "BSRSPYL ", 8) == 0)
 		cFYI(1, "dummy signature received for smb command 0x%x",
 			cifs_pdu->Command);

 	/* save off the origiginal signature so we can modify the smb and check
 		its signature against what the server sent */
 	memcpy(server_response_sig, cifs_pdu->Signature.SecuritySignature, 8);

 	cifs_pdu->Signature.Sequence.SequenceNumber =
 					cpu_to_le32(expected_sequence_number);
 	cifs_pdu->Signature.Sequence.Reserved = 0;

 	rc = cifs_calculate_signature(cifs_pdu, session_key,
 		what_we_think_sig_should_be);

 	if (rc)
 		return rc;

 /*	cifs_dump_mem("what we think it should be: ",
 		      what_we_think_sig_should_be, 16); */

 	if (memcmp(server_response_sig, what_we_think_sig_should_be, 8))
 		return -EACCES;
 	else
 		return 0;

 }

 /* We fill in key by putting in 40 byte array which was allocated by caller */
 int cifs_calculate_session_key(struct session_key *key, const char *rn,
 			   const char *password)
 {
 	char temp_key[16];
 	if ((key == NULL) || (rn == NULL))
 		return -EINVAL;

 	E_md4hash(password, temp_key);
 	mdfour(key->data.ntlm, temp_key, 16);
 	memcpy(key->data.ntlm+16, rn, CIFS_SESS_KEY_SIZE);
 	key->len = 40;
 	return 0;
 }

 #ifdef CONFIG_CIFS_WEAK_PW_HASH
 void calc_lanman_hash(const char *password, const char *cryptkey, bool encrypt,
 			char *lnm_session_key)
 {
 	int i;
 	char password_with_pad[CIFS_ENCPWD_SIZE];

 	memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
 	if (password)
 		strncpy(password_with_pad, password, CIFS_ENCPWD_SIZE);

 	if (!encrypt && global_secflags & CIFSSEC_MAY_PLNTXT) {
 		memset(lnm_session_key, 0, CIFS_SESS_KEY_SIZE);
 		memcpy(lnm_session_key, password_with_pad,
 			CIFS_ENCPWD_SIZE);
 		return;
 	}

 	/* calculate old style session key */
 	/* calling toupper is less broken than repeatedly
 	calling nls_toupper would be since that will never
 	work for UTF8, but neither handles multibyte code pages
 	but the only alternative would be converting to UCS-16 (Unicode)
 	(using a routine something like UniStrupr) then
 	uppercasing and then converting back from Unicode - which
 	would only worth doing it if we knew it were utf8. Basically
 	utf8 and other multibyte codepages each need their own strupper
 	function since a byte at a time will ont work. */

 	for (i = 0; i < CIFS_ENCPWD_SIZE; i++)
 		password_with_pad[i] = toupper(password_with_pad[i]);

 	SMBencrypt(password_with_pad, cryptkey, lnm_session_key);

 	/* clear password before we return/free memory */
 	memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
 }
 #endif /* CIFS_WEAK_PW_HASH */

 /* Build a proper attribute value/target info pairs blob.
  * Fill in netbios and dns domain name and workstation name
  * and client time (total five av pairs and + one end of fields indicator.
  * Allocate domain name which gets freed when session struct is deallocated.
  */
 static int
 build_avpair_blob(struct cifsSesInfo *ses, const struct nls_table *nls_cp)
 {
 	unsigned int dlen;
 	unsigned int wlen;
 	unsigned int size = 6 * sizeof(struct ntlmssp2_name);
 	__le64  curtime;
 	char *defdmname = "WORKGROUP";
 	unsigned char *blobptr;
 	struct ntlmssp2_name *attrptr;

 	if (!ses->domainName) {
 		ses->domainName = kstrdup(defdmname, GFP_KERNEL);
 		if (!ses->domainName)
 			return -ENOMEM;
 	}

 	dlen = strlen(ses->domainName);
 	wlen = strlen(ses->server->hostname);

 	/* The length of this blob is a size which is
 	 * six times the size of a structure which holds name/size +
 	 * two times the unicode length of a domain name +
 	 * two times the unicode length of a server name +
 	 * size of a timestamp (which is 8 bytes).
 	 */
 	ses->tilen = size + 2 * (2 * dlen) + 2 * (2 * wlen) + 8;
 	ses->tiblob = kzalloc(ses->tilen, GFP_KERNEL);
 	if (!ses->tiblob) {
 		ses->tilen = 0;
 		cERROR(1, "Challenge target info allocation failure");
 		return -ENOMEM;
 	}

 	blobptr = ses->tiblob;
 	attrptr = (struct ntlmssp2_name *) blobptr;

 	attrptr->type = cpu_to_le16(NTLMSSP_AV_NB_DOMAIN_NAME);
 	attrptr->length = cpu_to_le16(2 * dlen);
 	blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
 	cifs_strtoUCS((__le16 *)blobptr, ses->domainName, dlen, nls_cp);

 	blobptr += 2 * dlen;
 	attrptr = (struct ntlmssp2_name *) blobptr;

 	attrptr->type = cpu_to_le16(NTLMSSP_AV_NB_COMPUTER_NAME);
 	attrptr->length = cpu_to_le16(2 * wlen);
 	blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
 	cifs_strtoUCS((__le16 *)blobptr, ses->server->hostname, wlen, nls_cp);

 	blobptr += 2 * wlen;
 	attrptr = (struct ntlmssp2_name *) blobptr;

 	attrptr->type = cpu_to_le16(NTLMSSP_AV_DNS_DOMAIN_NAME);
 	attrptr->length = cpu_to_le16(2 * dlen);
 	blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
 	cifs_strtoUCS((__le16 *)blobptr, ses->domainName, dlen, nls_cp);

 	blobptr += 2 * dlen;
 	attrptr = (struct ntlmssp2_name *) blobptr;

 	attrptr->type = cpu_to_le16(NTLMSSP_AV_DNS_COMPUTER_NAME);
 	attrptr->length = cpu_to_le16(2 * wlen);
 	blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
 	cifs_strtoUCS((__le16 *)blobptr, ses->server->hostname, wlen, nls_cp);

 	blobptr += 2 * wlen;
 	attrptr = (struct ntlmssp2_name *) blobptr;

 	attrptr->type = cpu_to_le16(NTLMSSP_AV_TIMESTAMP);
 	attrptr->length = cpu_to_le16(sizeof(__le64));
 	blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
 	curtime = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
 	memcpy(blobptr, &curtime, sizeof(__le64));

 	return 0;
 }

 /* Server has provided av pairs/target info in the type 2 challenge
  * packet and we have plucked it and stored within smb session.
  * We parse that blob here to find netbios domain name to be used
  * as part of ntlmv2 authentication (in Target String), if not already
  * specified on the command line.
  * If this function returns without any error but without fetching
  * domain name, authentication may fail against some server but
  * may not fail against other (those who are not very particular
  * about target string i.e. for some, just user name might suffice.
  */
 static int
 find_domain_name(struct cifsSesInfo *ses)
 {
 	unsigned int attrsize;
 	unsigned int type;
 	unsigned int onesize = sizeof(struct ntlmssp2_name);
 	unsigned char *blobptr;
 	unsigned char *blobend;
 	struct ntlmssp2_name *attrptr;

 	if (!ses->tilen || !ses->tiblob)
 		return 0;

 	blobptr = ses->tiblob;
 	blobend = ses->tiblob + ses->tilen;

 	while (blobptr + onesize < blobend) {
 		attrptr = (struct ntlmssp2_name *) blobptr;
 		type = le16_to_cpu(attrptr->type);
 		if (type == NTLMSSP_AV_EOL)
 			break;
 		blobptr += 2; /* advance attr type */
 		attrsize = le16_to_cpu(attrptr->length);
 		blobptr += 2; /* advance attr size */
 		if (blobptr + attrsize > blobend)
 			break;
 		if (type == NTLMSSP_AV_NB_DOMAIN_NAME) {
 			if (!attrsize)
 				break;
 			if (!ses->domainName) {
 				struct nls_table *default_nls;
 				ses->domainName =
 					kmalloc(attrsize + 1, GFP_KERNEL);
 				if (!ses->domainName)
 						return -ENOMEM;
 				default_nls = load_nls_default();
 				cifs_from_ucs2(ses->domainName,
 					(__le16 *)blobptr, attrsize, attrsize,
 					default_nls, false);
 				unload_nls(default_nls);
 				break;
 			}
 		}
 		blobptr += attrsize; /* advance attr  value */
 	}

 	return 0;
 }

 static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
 			    const struct nls_table *nls_cp)
 {
 	int rc = 0;
 	int len;
 	char nt_hash[16];
 	struct HMACMD5Context *pctxt;
 	wchar_t *user;
 	wchar_t *domain;

 	pctxt = kmalloc(sizeof(struct HMACMD5Context), GFP_KERNEL);

 	if (pctxt == NULL)
 		return -ENOMEM;

 	/* calculate md4 hash of password */
 	E_md4hash(ses->password, nt_hash);

 	/* convert Domainname to unicode and uppercase */
 	hmac_md5_init_limK_to_64(nt_hash, 16, pctxt);

 	/* convert ses->userName to unicode and uppercase */
 	len = strlen(ses->userName);
 	user = kmalloc(2 + (len * 2), GFP_KERNEL);
 	if (user == NULL)
 		goto calc_exit_2;
 	len = cifs_strtoUCS((__le16 *)user, ses->userName, len, nls_cp);
 	UniStrupr(user);
 	hmac_md5_update((char *)user, 2*len, pctxt);

 	/* convert ses->domainName to unicode and uppercase */
 	if (ses->domainName) {
 		len = strlen(ses->domainName);

 		domain = kmalloc(2 + (len * 2), GFP_KERNEL);
 		if (domain == NULL)
 			goto calc_exit_1;
 		len = cifs_strtoUCS((__le16 *)domain, ses->domainName, len,
 					nls_cp);
 		/* the following line was removed since it didn't work well
 		   with lower cased domain name that passed as an option.
 		   Maybe converting the domain name earlier makes sense */
 		/* UniStrupr(domain); */

 		hmac_md5_update((char *)domain, 2*len, pctxt);

 		kfree(domain);
 	}
 calc_exit_1:
 	kfree(user);
 calc_exit_2:
 	/* BB FIXME what about bytes 24 through 40 of the signing key?
 	   compare with the NTLM example */
 	hmac_md5_final(ses->ntlmv2_hash, pctxt);

 	kfree(pctxt);
 	return rc;
 }

 int
 setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,
 		      const struct nls_table *nls_cp)
 {
 	int rc;
 	struct ntlmv2_resp *buf = (struct ntlmv2_resp *)resp_buf;
 	struct HMACMD5Context context;

 	buf->blob_signature = cpu_to_le32(0x00000101);
 	buf->reserved = 0;
 	buf->time = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
 	get_random_bytes(&buf->client_chal, sizeof(buf->client_chal));
 	buf->reserved2 = 0;

 	if (ses->server->secType == RawNTLMSSP) {
 		if (!ses->domainName) {
 			rc = find_domain_name(ses);
 			if (rc) {
 				cERROR(1, "error %d finding domain name", rc);
 				goto setup_ntlmv2_rsp_ret;
 			}
 		}
 	} else {
 		rc = build_avpair_blob(ses, nls_cp);
 		if (rc) {
 			cERROR(1, "error %d building av pair blob", rc);
 			return rc;
 		}
 	}

 	/* calculate buf->ntlmv2_hash */
 	rc = calc_ntlmv2_hash(ses, nls_cp);
 	if (rc) {
 		cERROR(1, "could not get v2 hash rc %d", rc);
 		goto setup_ntlmv2_rsp_ret;
 	}
 	CalcNTLMv2_response(ses, resp_buf);

 	/* now calculate the session key for NTLMv2 */
 	hmac_md5_init_limK_to_64(ses->ntlmv2_hash, 16, &context);
 	hmac_md5_update(resp_buf, 16, &context);
 	hmac_md5_final(ses->auth_key.data.ntlmv2.key, &context);

 	memcpy(&ses->auth_key.data.ntlmv2.resp, resp_buf,
 	       sizeof(struct ntlmv2_resp));
 	ses->auth_key.len = 16 + sizeof(struct ntlmv2_resp);

 	return 0;

 setup_ntlmv2_rsp_ret:
 	kfree(ses->tiblob);
 	ses->tiblob = NULL;
 	ses->tilen = 0;

 	return rc;
 }

 void CalcNTLMv2_response(const struct cifsSesInfo *ses,
 			 char *v2_session_response)
 {
 	struct HMACMD5Context context;
 	/* rest of v2 struct already generated */
 	memcpy(v2_session_response + 8, ses->cryptKey, 8);
 	hmac_md5_init_limK_to_64(ses->ntlmv2_hash, 16, &context);

 	hmac_md5_update(v2_session_response+8,
 			sizeof(struct ntlmv2_resp) - 8, &context);

 	if (ses->tilen)
 		hmac_md5_update(ses->tiblob, ses->tilen, &context);

 	hmac_md5_final(v2_session_response, &context);
 /*	cifs_dump_mem("v2_sess_rsp: ", v2_session_response, 32); */
 }
	/*
	* fs/cifs/cifsencrypt.c
	*
	* Copyright (C) International Business Machines Corp., 2005,2006
	* 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 <linux/fs.h>
	#include <linux/slab.h>
	#include "cifspdu.h"
	#include "cifsglob.h"
	#include "cifs_debug.h"
	#include "md5.h"
	#include "cifs_unicode.h"
	#include "cifsproto.h"
	#include "ntlmssp.h"
	#include <linux/ctype.h>
	#include <linux/random.h>

	/* Calculate and return the CIFS signature based on the mac key and SMB PDU */
	/* the 16 byte signature must be allocated by the caller */
	/* Note we only use the 1st eight bytes */
	/* Note that the smb header signature field on input contains the
	sequence number before this function is called */

	extern void mdfour(unsigned char out, unsigned char in, int n);
	extern void E_md4hash(const unsigned char passwd, unsigned char p16);
	extern void SMBencrypt(unsigned char passwd, const unsigned char c8,
	unsigned char *p24);

	static int cifs_calculate_signature(const struct smb_hdr *cifs_pdu,
	const struct session_key key, char signature)
	{
	struct MD5Context context;

	if ((cifs_pdu == NULL) \|\| (signature == NULL) \|\| (key == NULL))
	return -EINVAL;

	cifs_MD5_init(&context);
	cifs_MD5_update(&context, (char *)&key->data, key->len);
	cifs_MD5_update(&context, cifs_pdu->Protocol, cifs_pdu->smb_buf_length);

	cifs_MD5_final(signature, &context);
	return 0;
	}

	int cifs_sign_smb(struct smb_hdr cifs_pdu, struct TCP_Server_Info server,
	__u32 *pexpected_response_sequence_number)
	{
	int rc = 0;
	char smb_signature[20];

	if ((cifs_pdu == NULL) \|\| (server == NULL))
	return -EINVAL;

	if ((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
	return rc;

	spin_lock(&GlobalMid_Lock);
	cifs_pdu->Signature.Sequence.SequenceNumber =
	cpu_to_le32(server->sequence_number);
	cifs_pdu->Signature.Sequence.Reserved = 0;

	*pexpected_response_sequence_number = server->sequence_number++;
	server->sequence_number++;
	spin_unlock(&GlobalMid_Lock);

	rc = cifs_calculate_signature(cifs_pdu, &server->session_key,
	smb_signature);
	if (rc)
	memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
	else
	memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);

	return rc;
	}

	static int cifs_calc_signature2(const struct kvec *iov, int n_vec,
	const struct session_key key, char signature)
	{
	struct MD5Context context;
	int i;

	if ((iov == NULL) \|\| (signature == NULL) \|\| (key == NULL))
	return -EINVAL;

	cifs_MD5_init(&context);
	cifs_MD5_update(&context, (char *)&key->data, key->len);
	for (i = 0; i < n_vec; i++) {
	if (iov[i].iov_len == 0)
	continue;
	if (iov[i].iov_base == NULL) {
	cERROR(1, "null iovec entry");
	return -EIO;
	}
	/* The first entry includes a length field (which does not get
	signed that occupies the first 4 bytes before the header */
	if (i == 0) {
	if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
	break; /* nothing to sign or corrupt header */
	cifs_MD5_update(&context, iov[0].iov_base+4,
	iov[0].iov_len-4);
	} else
	cifs_MD5_update(&context, iov[i].iov_base, iov[i].iov_len);
	}

	cifs_MD5_final(signature, &context);

	return 0;
	}


	int cifs_sign_smb2(struct kvec iov, int n_vec, struct TCP_Server_Info server,
	__u32 *pexpected_response_sequence_number)
	{
	int rc = 0;
	char smb_signature[20];
	struct smb_hdr *cifs_pdu = iov[0].iov_base;

	if ((cifs_pdu == NULL) \|\| (server == NULL))
	return -EINVAL;

	if ((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
	return rc;

	spin_lock(&GlobalMid_Lock);
	cifs_pdu->Signature.Sequence.SequenceNumber =
	cpu_to_le32(server->sequence_number);
	cifs_pdu->Signature.Sequence.Reserved = 0;

	*pexpected_response_sequence_number = server->sequence_number++;
	server->sequence_number++;
	spin_unlock(&GlobalMid_Lock);

	rc = cifs_calc_signature2(iov, n_vec, &server->session_key,
	smb_signature);
	if (rc)
	memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
	else
	memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);

	return rc;
	}

	int cifs_verify_signature(struct smb_hdr *cifs_pdu,
	const struct session_key *session_key,
	__u32 expected_sequence_number)
	{
	unsigned int rc;
	char server_response_sig[8];
	char what_we_think_sig_should_be[20];

	if (cifs_pdu == NULL \|\| session_key == NULL)
	return -EINVAL;

	if (cifs_pdu->Command == SMB_COM_NEGOTIATE)
	return 0;

	if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) {
	struct smb_com_lock_req *pSMB =
	(struct smb_com_lock_req *)cifs_pdu;
	if (pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE)
	return 0;
	}

	/* BB what if signatures are supposed to be on for session but
	server does not send one? BB */

	/* Do not need to verify session setups with signature "BSRSPYL " */
	if (memcmp(cifs_pdu->Signature.SecuritySignature, "BSRSPYL ", 8) == 0)
	cFYI(1, "dummy signature received for smb command 0x%x",
	cifs_pdu->Command);

	/* save off the origiginal signature so we can modify the smb and check
	its signature against what the server sent */
	memcpy(server_response_sig, cifs_pdu->Signature.SecuritySignature, 8);

	cifs_pdu->Signature.Sequence.SequenceNumber =
	cpu_to_le32(expected_sequence_number);
	cifs_pdu->Signature.Sequence.Reserved = 0;

	rc = cifs_calculate_signature(cifs_pdu, session_key,
	what_we_think_sig_should_be);

	if (rc)
	return rc;

	/* cifs_dump_mem("what we think it should be: ",
	what_we_think_sig_should_be, 16); */

	if (memcmp(server_response_sig, what_we_think_sig_should_be, 8))
	return -EACCES;
	else
	return 0;

	}

	/* We fill in key by putting in 40 byte array which was allocated by caller */
	int cifs_calculate_session_key(struct session_key key, const char rn,
	const char *password)
	{
	char temp_key[16];
	if ((key == NULL) \|\| (rn == NULL))
	return -EINVAL;

	E_md4hash(password, temp_key);
	mdfour(key->data.ntlm, temp_key, 16);
	memcpy(key->data.ntlm+16, rn, CIFS_SESS_KEY_SIZE);
	key->len = 40;
	return 0;
	}

	#ifdef CONFIG_CIFS_WEAK_PW_HASH
	void calc_lanman_hash(const char password, const char cryptkey, bool encrypt,
	char *lnm_session_key)
	{
	int i;
	char password_with_pad[CIFS_ENCPWD_SIZE];

	memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
	if (password)
	strncpy(password_with_pad, password, CIFS_ENCPWD_SIZE);

	if (!encrypt && global_secflags & CIFSSEC_MAY_PLNTXT) {
	memset(lnm_session_key, 0, CIFS_SESS_KEY_SIZE);
	memcpy(lnm_session_key, password_with_pad,
	CIFS_ENCPWD_SIZE);
	return;
	}

	/* calculate old style session key */
	/* calling toupper is less broken than repeatedly
	calling nls_toupper would be since that will never
	work for UTF8, but neither handles multibyte code pages
	but the only alternative would be converting to UCS-16 (Unicode)
	(using a routine something like UniStrupr) then
	uppercasing and then converting back from Unicode - which
	would only worth doing it if we knew it were utf8. Basically
	utf8 and other multibyte codepages each need their own strupper
	function since a byte at a time will ont work. */

	for (i = 0; i < CIFS_ENCPWD_SIZE; i++)
	password_with_pad[i] = toupper(password_with_pad[i]);

	SMBencrypt(password_with_pad, cryptkey, lnm_session_key);

	/* clear password before we return/free memory */
	memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
	}
	#endif /* CIFS_WEAK_PW_HASH */

	/* Build a proper attribute value/target info pairs blob.
	* Fill in netbios and dns domain name and workstation name
	* and client time (total five av pairs and + one end of fields indicator.
	* Allocate domain name which gets freed when session struct is deallocated.
	*/
	static int
	build_avpair_blob(struct cifsSesInfo ses, const struct nls_table nls_cp)
	{
	unsigned int dlen;
	unsigned int wlen;
	unsigned int size = 6 * sizeof(struct ntlmssp2_name);
	__le64 curtime;
	char *defdmname = "WORKGROUP";
	unsigned char *blobptr;
	struct ntlmssp2_name *attrptr;

	if (!ses->domainName) {
	ses->domainName = kstrdup(defdmname, GFP_KERNEL);
	if (!ses->domainName)
	return -ENOMEM;
	}

	dlen = strlen(ses->domainName);
	wlen = strlen(ses->server->hostname);

	/* The length of this blob is a size which is
	* six times the size of a structure which holds name/size +
	* two times the unicode length of a domain name +
	* two times the unicode length of a server name +
	* size of a timestamp (which is 8 bytes).
	*/
	ses->tilen = size + 2 * (2 * dlen) + 2 * (2 * wlen) + 8;
	ses->tiblob = kzalloc(ses->tilen, GFP_KERNEL);
	if (!ses->tiblob) {
	ses->tilen = 0;
	cERROR(1, "Challenge target info allocation failure");
	return -ENOMEM;
	}

	blobptr = ses->tiblob;
	attrptr = (struct ntlmssp2_name *) blobptr;

	attrptr->type = cpu_to_le16(NTLMSSP_AV_NB_DOMAIN_NAME);
	attrptr->length = cpu_to_le16(2 * dlen);
	blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
	cifs_strtoUCS((__le16 *)blobptr, ses->domainName, dlen, nls_cp);

	blobptr += 2 * dlen;
	attrptr = (struct ntlmssp2_name *) blobptr;

	attrptr->type = cpu_to_le16(NTLMSSP_AV_NB_COMPUTER_NAME);
	attrptr->length = cpu_to_le16(2 * wlen);
	blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
	cifs_strtoUCS((__le16 *)blobptr, ses->server->hostname, wlen, nls_cp);

	blobptr += 2 * wlen;
	attrptr = (struct ntlmssp2_name *) blobptr;

	attrptr->type = cpu_to_le16(NTLMSSP_AV_DNS_DOMAIN_NAME);
	attrptr->length = cpu_to_le16(2 * dlen);
	blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
	cifs_strtoUCS((__le16 *)blobptr, ses->domainName, dlen, nls_cp);

	blobptr += 2 * dlen;
	attrptr = (struct ntlmssp2_name *) blobptr;

	attrptr->type = cpu_to_le16(NTLMSSP_AV_DNS_COMPUTER_NAME);
	attrptr->length = cpu_to_le16(2 * wlen);
	blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
	cifs_strtoUCS((__le16 *)blobptr, ses->server->hostname, wlen, nls_cp);

	blobptr += 2 * wlen;
	attrptr = (struct ntlmssp2_name *) blobptr;

	attrptr->type = cpu_to_le16(NTLMSSP_AV_TIMESTAMP);
	attrptr->length = cpu_to_le16(sizeof(__le64));
	blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
	curtime = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
	memcpy(blobptr, &curtime, sizeof(__le64));

	return 0;
	}

	/* Server has provided av pairs/target info in the type 2 challenge
	* packet and we have plucked it and stored within smb session.
	* We parse that blob here to find netbios domain name to be used
	* as part of ntlmv2 authentication (in Target String), if not already
	* specified on the command line.
	* If this function returns without any error but without fetching
	* domain name, authentication may fail against some server but
	* may not fail against other (those who are not very particular
	* about target string i.e. for some, just user name might suffice.
	*/
	static int
	find_domain_name(struct cifsSesInfo *ses)
	{
	unsigned int attrsize;
	unsigned int type;
	unsigned int onesize = sizeof(struct ntlmssp2_name);
	unsigned char *blobptr;
	unsigned char *blobend;
	struct ntlmssp2_name *attrptr;

	if (!ses->tilen \|\| !ses->tiblob)
	return 0;

	blobptr = ses->tiblob;
	blobend = ses->tiblob + ses->tilen;

	while (blobptr + onesize < blobend) {
	attrptr = (struct ntlmssp2_name *) blobptr;
	type = le16_to_cpu(attrptr->type);
	if (type == NTLMSSP_AV_EOL)
	break;
	blobptr += 2; /* advance attr type */
	attrsize = le16_to_cpu(attrptr->length);
	blobptr += 2; /* advance attr size */
	if (blobptr + attrsize > blobend)
	break;
	if (type == NTLMSSP_AV_NB_DOMAIN_NAME) {
	if (!attrsize)
	break;
	if (!ses->domainName) {
	struct nls_table *default_nls;
	ses->domainName =
	kmalloc(attrsize + 1, GFP_KERNEL);
	if (!ses->domainName)
	return -ENOMEM;
	default_nls = load_nls_default();
	cifs_from_ucs2(ses->domainName,
	(__le16 *)blobptr, attrsize, attrsize,
	default_nls, false);
	unload_nls(default_nls);
	break;
	}
	}
	blobptr += attrsize; /* advance attr value */
	}

	return 0;
	}

	static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
	const struct nls_table *nls_cp)
	{
	int rc = 0;
	int len;
	char nt_hash[16];
	struct HMACMD5Context *pctxt;
	wchar_t *user;
	wchar_t *domain;

	pctxt = kmalloc(sizeof(struct HMACMD5Context), GFP_KERNEL);

	if (pctxt == NULL)
	return -ENOMEM;

	/* calculate md4 hash of password */
	E_md4hash(ses->password, nt_hash);

	/* convert Domainname to unicode and uppercase */
	hmac_md5_init_limK_to_64(nt_hash, 16, pctxt);

	/* convert ses->userName to unicode and uppercase */
	len = strlen(ses->userName);
	user = kmalloc(2 + (len * 2), GFP_KERNEL);
	if (user == NULL)
	goto calc_exit_2;
	len = cifs_strtoUCS((__le16 *)user, ses->userName, len, nls_cp);
	UniStrupr(user);
	hmac_md5_update((char )user, 2len, pctxt);

	/* convert ses->domainName to unicode and uppercase */
	if (ses->domainName) {
	len = strlen(ses->domainName);

	domain = kmalloc(2 + (len * 2), GFP_KERNEL);
	if (domain == NULL)
	goto calc_exit_1;
	len = cifs_strtoUCS((__le16 *)domain, ses->domainName, len,
	nls_cp);
	/* the following line was removed since it didn't work well
	with lower cased domain name that passed as an option.
	Maybe converting the domain name earlier makes sense */
	/* UniStrupr(domain); */

	hmac_md5_update((char )domain, 2len, pctxt);

	kfree(domain);
	}
	calc_exit_1:
	kfree(user);
	calc_exit_2:
	/* BB FIXME what about bytes 24 through 40 of the signing key?
	compare with the NTLM example */
	hmac_md5_final(ses->ntlmv2_hash, pctxt);

	kfree(pctxt);
	return rc;
	}

	int
	setup_ntlmv2_rsp(struct cifsSesInfo ses, char resp_buf,
	const struct nls_table *nls_cp)
	{
	int rc;
	struct ntlmv2_resp buf = (struct ntlmv2_resp )resp_buf;
	struct HMACMD5Context context;

	buf->blob_signature = cpu_to_le32(0x00000101);
	buf->reserved = 0;
	buf->time = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
	get_random_bytes(&buf->client_chal, sizeof(buf->client_chal));
	buf->reserved2 = 0;

	if (ses->server->secType == RawNTLMSSP) {
	if (!ses->domainName) {
	rc = find_domain_name(ses);
	if (rc) {
	cERROR(1, "error %d finding domain name", rc);
	goto setup_ntlmv2_rsp_ret;
	}
	}
	} else {
	rc = build_avpair_blob(ses, nls_cp);
	if (rc) {
	cERROR(1, "error %d building av pair blob", rc);
	return rc;
	}
	}

	/* calculate buf->ntlmv2_hash */
	rc = calc_ntlmv2_hash(ses, nls_cp);
	if (rc) {
	cERROR(1, "could not get v2 hash rc %d", rc);
	goto setup_ntlmv2_rsp_ret;
	}
	CalcNTLMv2_response(ses, resp_buf);

	/* now calculate the session key for NTLMv2 */
	hmac_md5_init_limK_to_64(ses->ntlmv2_hash, 16, &context);
	hmac_md5_update(resp_buf, 16, &context);
	hmac_md5_final(ses->auth_key.data.ntlmv2.key, &context);

	memcpy(&ses->auth_key.data.ntlmv2.resp, resp_buf,
	sizeof(struct ntlmv2_resp));
	ses->auth_key.len = 16 + sizeof(struct ntlmv2_resp);

	return 0;

	setup_ntlmv2_rsp_ret:
	kfree(ses->tiblob);
	ses->tiblob = NULL;
	ses->tilen = 0;

	return rc;
	}

	void CalcNTLMv2_response(const struct cifsSesInfo *ses,
	char *v2_session_response)
	{
	struct HMACMD5Context context;
	/* rest of v2 struct already generated */
	memcpy(v2_session_response + 8, ses->cryptKey, 8);
	hmac_md5_init_limK_to_64(ses->ntlmv2_hash, 16, &context);

	hmac_md5_update(v2_session_response+8,
	sizeof(struct ntlmv2_resp) - 8, &context);

	if (ses->tilen)
	hmac_md5_update(ses->tiblob, ses->tilen, &context);

	hmac_md5_final(v2_session_response, &context);
	/* cifs_dump_mem("v2_sess_rsp: ", v2_session_response, 32); */
	}