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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright 2018 Nexenta Systems, Inc. All rights reserved.
* Copyright 2020 RackTop Systems, Inc.
*/
#include <smbsrv/smb_kcrypt.h>
#include <sys/types.h>
#include <sys/sysmacros.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
/*
* Derive SMB3 key as described in [MS-SMB2] 3.1.4.2
* and [NIST SP800-108]
*
* r = 32, L = 128, PRF = HMAC-SHA256, key = (session key)
*/
/*
* SMB 3.0.2 KDF Input
*
* Session.SigningKey for binding a session:
* - Session.SessionKey as K1
* - label = "SMB2AESCMAC" (size 12)
* - context = "SmbSign" (size 8)
* Channel.SigningKey for for all other requests
* - if SMB2_SESSION_FLAG_BINDING, GSS key (in Session.SessionKey?) as K1;
* - otherwise, Session.SessionKey as K1
* - label = "SMB2AESCMAC" (size 12)
* - context = "SmbSign" (size 8)
* Session.ApplicationKey for ... (not sure what yet)
* - Session.SessionKey as K1
* - label = "SMB2APP" (size 8)
* - context = "SmbRpc" (size 7)
* Session.EncryptionKey for encrypting server messages
* - Session.SessionKey as K1
* - label = "SMB2AESCCM" (size 11)
* - context = "ServerOut" (size 10)
* Session.DecryptionKey for decrypting client requests
* - Session.SessionKey as K1
* - label = "SMB2AESCCM" (size 11)
* - context = "ServerIn " (size 10) (Note the space)
*/
/*
* SMB 3.1.1 KDF Input
*
* Session.SigningKey for binding a session:
* - Session.SessionKey as K1
* - label = "SMBSigningKey" (size 14)
* - context = preauth hashval
* Channel.SigningKey for for all other requests
* - if SMB2_SESSION_FLAG_BINDING, GSS key (in Session.SessionKey?) as K1;
* - otherwise, Session.SessionKey as K1
* - label = "SMBSigningKey" (size 14)
* - context = preauth hashval
* Session.EncryptionKey for encrypting server messages
* - Session.SessionKey as K1
* - label = "SMBS2CCipherKey" (size 16)
* - context = preauth hashval
* Session.DecryptionKey for decrypting client requests
* - Session.SessionKey as K1
* - label = "SMBC2SCipherKey" (size 16)
* - context = preauth hashval
*/
/*
* SMB3KDF(Ki, Label, Context)
* counter || Label || 0x00 || Context || L
*/
int
smb3_kdf(uint8_t *outbuf,
uint8_t *key, size_t key_len,
uint8_t *label, size_t label_len,
uint8_t *context, size_t context_len)
{
static uint8_t L[4] = { 0, 0, 0, 0x80 };
uint8_t digest32[SHA256_DIGEST_LENGTH];
/* Maximum length of kdf input is 89 for Encription/Decryption key */
uint8_t kdfbuf[89] = { 0, 0, 0, 1 }; /* initialized by counter */
smb_crypto_mech_t mech;
smb_sign_ctx_t hctx = 0;
int pos = 4; /* skip counter */
int rc;
bcopy(label, &kdfbuf[pos], label_len);
pos += label_len;
kdfbuf[pos] = 0;
pos++;
bcopy(context, &kdfbuf[pos], context_len);
pos += context_len;
bcopy(L, &kdfbuf[pos], 4);
pos += 4;
bzero(&mech, sizeof (mech));
if ((rc = smb2_hmac_getmech(&mech)) != 0)
return (rc);
/* Limit the SessionKey input to its maximum size (16 bytes) */
rc = smb2_hmac_init(&hctx, &mech, key, MIN(key_len, SMB2_KEYLEN));
if (rc != 0)
return (rc);
if ((rc = smb2_hmac_update(hctx, kdfbuf, pos)) != 0)
return (rc);
if ((rc = smb2_hmac_final(hctx, digest32)) != 0)
return (rc);
/* Output is first 16 bytes of digest. */
bcopy(digest32, outbuf, SMB3_KEYLEN);
return (0);
}
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