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// SPDX-License-Identifier: LGPL-2.1
/*
*
* Encryption and hashing operations relating to NTLM, NTLMv2. See MS-NLMP
* for more detailed information
*
* Copyright (C) International Business Machines Corp., 2005,2013
* Author(s): Steve French (sfrench@us.ibm.com)
*
*/
#include <linux/fips.h>
#include <crypto/md5.h>
#include <crypto/utils.h>
#include "cifsproto.h"
#include "smb1proto.h"
#include "cifs_debug.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 and that the smb header signature field on input contains
* the sequence number before this function is called. Also, this function
* should be called with the server->srv_mutex held.
*/
static int cifs_calc_signature(struct smb_rqst *rqst,
struct TCP_Server_Info *server, char *signature)
{
struct md5_ctx ctx;
if (!rqst->rq_iov || !signature || !server)
return -EINVAL;
if (fips_enabled) {
cifs_dbg(VFS,
"MD5 signature support is disabled due to FIPS\n");
return -EOPNOTSUPP;
}
md5_init(&ctx);
md5_update(&ctx, server->session_key.response, server->session_key.len);
return __cifs_calc_signature(
rqst, server, signature,
&(struct cifs_calc_sig_ctx){ .md5 = &ctx });
}
/* must be called with server->srv_mutex held */
int cifs_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server,
__u32 *pexpected_response_sequence_number)
{
int rc = 0;
char smb_signature[20];
struct smb_hdr *cifs_pdu = (struct smb_hdr *)rqst->rq_iov[0].iov_base;
if ((cifs_pdu == NULL) || (server == NULL))
return -EINVAL;
spin_lock(&server->srv_lock);
if (!(cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) ||
server->tcpStatus == CifsNeedNegotiate) {
spin_unlock(&server->srv_lock);
return rc;
}
spin_unlock(&server->srv_lock);
if (!server->session_estab) {
memcpy(cifs_pdu->Signature.SecuritySignature, "BSRSPYL", 8);
return rc;
}
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;
rc = cifs_calc_signature(rqst, server, 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_rqst *rqst,
struct TCP_Server_Info *server,
__u32 expected_sequence_number)
{
unsigned int rc;
char server_response_sig[8];
char what_we_think_sig_should_be[20];
struct smb_hdr *cifs_pdu = (struct smb_hdr *)rqst->rq_iov[0].iov_base;
if (cifs_pdu == NULL || server == NULL)
return -EINVAL;
if (!server->session_estab)
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)
cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n",
cifs_pdu->Command);
/* save off the original 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;
cifs_server_lock(server);
rc = cifs_calc_signature(rqst, server, what_we_think_sig_should_be);
cifs_server_unlock(server);
if (rc)
return rc;
/* cifs_dump_mem("what we think it should be: ",
what_we_think_sig_should_be, 16); */
if (crypto_memneq(server_response_sig, what_we_think_sig_should_be, 8))
return -EACCES;
else
return 0;
}
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