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/*
* Copyright (c) 2020 Andreas Schneider <asn@samba.org>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "librpc/gen_ndr/security.h"
#include "librpc/gen_ndr/auth.h"
#include "lib/crypto/gnutls_helpers.h"
#include "libcli/security/dom_sid.h"
#include "libcli/security/security_token.h"
#include "libcli/smb/smb2_constants.h"
#include "dcerpc_helper.h"
static bool smb3_sid_parse(const struct dom_sid *sid,
uint16_t *pdialect,
uint16_t *pencrypt,
uint16_t *pcipher)
{
uint16_t dialect;
uint16_t encrypt;
uint16_t cipher;
if (sid->sub_auths[0] != global_sid_Samba_SMB3.sub_auths[0]) {
return false;
}
dialect = sid->sub_auths[1];
if (dialect > 0x03ff) {
return false;
}
encrypt = sid->sub_auths[2];
if (encrypt > 0x0002) {
return false;
}
cipher = sid->sub_auths[3];
if (cipher > 256) {
/*
* It is unlikely that we
* ever have more then 256
* encryption algorithms
*/
return false;
}
if (pdialect != NULL) {
*pdialect = dialect;
}
if (pencrypt != NULL) {
*pencrypt = encrypt;
}
if (pcipher != NULL) {
*pcipher = cipher;
}
return true;
}
bool dcerpc_is_transport_encrypted(struct auth_session_info *session_info)
{
struct security_token *token = session_info->security_token;
struct dom_sid smb3_dom_sid = global_sid_Samba_SMB3;
const struct dom_sid *smb3_sid = NULL;
uint16_t dialect = 0;
uint16_t encrypt = 0;
uint16_t cipher = 0;
size_t num_smb3_sids;
bool ok;
num_smb3_sids = security_token_count_flag_sids(token,
&smb3_dom_sid,
3,
&smb3_sid);
if (num_smb3_sids > 1) {
DBG_ERR("ERROR: The SMB3 SID has been detected %zu times\n",
num_smb3_sids);
return false;
}
if (smb3_sid == NULL) {
return false;
}
ok = smb3_sid_parse(smb3_sid, &dialect, &encrypt, &cipher);
if (!ok) {
DBG_ERR("Failed to parse SMB3 SID!\n");
return false;
}
DBG_DEBUG("SMB SID - dialect: %#04x, encrypt: %#04x, cipher: %#04x\n",
dialect,
encrypt,
cipher);
if (dialect < SMB3_DIALECT_REVISION_300) {
DBG_DEBUG("Invalid SMB3 dialect!\n");
return false;
}
if (encrypt != DCERPC_SMB_ENCRYPTION_REQUIRED) {
DBG_DEBUG("Invalid SMB3 encryption!\n");
return false;
}
switch (cipher) {
case SMB2_ENCRYPTION_AES128_CCM:
case SMB2_ENCRYPTION_AES128_GCM:
break;
default:
DBG_DEBUG("Invalid SMB3 cipher!\n");
return false;
}
return true;
}
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