CIFS: Enable encryption during session setup phase

In order to allow encryption on SMB connection we need to exchange
a session key and generate encryption and decryption keys.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
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;
}

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;
}
