![Shirish Pargaonkar](/assets/img/avatar_default.png)
Build an av pair blob as part of ntlmv2 (without extended security) auth request. Include netbios and dns names for domain and server and a timestamp in the blob. Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com> Reviewed-by: Jeff Layton <jlayton@samba.org> Signed-off-by: Steve French <sfrench@us.ibm.com>
541 lines
16 KiB
C
541 lines
16 KiB
C
/*
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* fs/cifs/cifsencrypt.c
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*
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* Copyright (C) International Business Machines Corp., 2005,2006
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* Author(s): Steve French (sfrench@us.ibm.com)
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published
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* by the Free Software Foundation; either version 2.1 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
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* the GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include "cifspdu.h"
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#include "cifsglob.h"
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#include "cifs_debug.h"
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#include "md5.h"
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#include "cifs_unicode.h"
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#include "cifsproto.h"
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#include "ntlmssp.h"
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#include <linux/ctype.h>
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#include <linux/random.h>
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/* Calculate and return the CIFS signature based on the mac key and SMB PDU */
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/* the 16 byte signature must be allocated by the caller */
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/* Note we only use the 1st eight bytes */
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/* Note that the smb header signature field on input contains the
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sequence number before this function is called */
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extern void mdfour(unsigned char *out, unsigned char *in, int n);
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extern void E_md4hash(const unsigned char *passwd, unsigned char *p16);
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extern void SMBencrypt(unsigned char *passwd, const unsigned char *c8,
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unsigned char *p24);
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static int cifs_calculate_signature(const struct smb_hdr *cifs_pdu,
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const struct session_key *key, char *signature)
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{
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struct MD5Context context;
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if ((cifs_pdu == NULL) || (signature == NULL) || (key == NULL))
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return -EINVAL;
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cifs_MD5_init(&context);
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cifs_MD5_update(&context, (char *)&key->data, key->len);
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cifs_MD5_update(&context, cifs_pdu->Protocol, cifs_pdu->smb_buf_length);
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cifs_MD5_final(signature, &context);
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return 0;
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}
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int cifs_sign_smb(struct smb_hdr *cifs_pdu, struct TCP_Server_Info *server,
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__u32 *pexpected_response_sequence_number)
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{
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int rc = 0;
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char smb_signature[20];
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if ((cifs_pdu == NULL) || (server == NULL))
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return -EINVAL;
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if ((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
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return rc;
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spin_lock(&GlobalMid_Lock);
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cifs_pdu->Signature.Sequence.SequenceNumber =
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cpu_to_le32(server->sequence_number);
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cifs_pdu->Signature.Sequence.Reserved = 0;
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*pexpected_response_sequence_number = server->sequence_number++;
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server->sequence_number++;
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spin_unlock(&GlobalMid_Lock);
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rc = cifs_calculate_signature(cifs_pdu, &server->session_key,
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smb_signature);
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if (rc)
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memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
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else
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memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
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return rc;
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}
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static int cifs_calc_signature2(const struct kvec *iov, int n_vec,
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const struct session_key *key, char *signature)
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{
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struct MD5Context context;
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int i;
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if ((iov == NULL) || (signature == NULL) || (key == NULL))
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return -EINVAL;
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cifs_MD5_init(&context);
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cifs_MD5_update(&context, (char *)&key->data, key->len);
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for (i = 0; i < n_vec; i++) {
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if (iov[i].iov_len == 0)
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continue;
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if (iov[i].iov_base == NULL) {
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cERROR(1, "null iovec entry");
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return -EIO;
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}
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/* The first entry includes a length field (which does not get
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signed that occupies the first 4 bytes before the header */
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if (i == 0) {
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if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
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break; /* nothing to sign or corrupt header */
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cifs_MD5_update(&context, iov[0].iov_base+4,
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iov[0].iov_len-4);
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} else
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cifs_MD5_update(&context, iov[i].iov_base, iov[i].iov_len);
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}
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cifs_MD5_final(signature, &context);
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return 0;
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}
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int cifs_sign_smb2(struct kvec *iov, int n_vec, struct TCP_Server_Info *server,
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__u32 *pexpected_response_sequence_number)
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{
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int rc = 0;
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char smb_signature[20];
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struct smb_hdr *cifs_pdu = iov[0].iov_base;
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if ((cifs_pdu == NULL) || (server == NULL))
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return -EINVAL;
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if ((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
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return rc;
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spin_lock(&GlobalMid_Lock);
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cifs_pdu->Signature.Sequence.SequenceNumber =
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cpu_to_le32(server->sequence_number);
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cifs_pdu->Signature.Sequence.Reserved = 0;
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*pexpected_response_sequence_number = server->sequence_number++;
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server->sequence_number++;
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spin_unlock(&GlobalMid_Lock);
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rc = cifs_calc_signature2(iov, n_vec, &server->session_key,
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smb_signature);
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if (rc)
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memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
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else
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memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
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return rc;
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}
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int cifs_verify_signature(struct smb_hdr *cifs_pdu,
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const struct session_key *session_key,
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__u32 expected_sequence_number)
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{
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unsigned int rc;
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char server_response_sig[8];
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char what_we_think_sig_should_be[20];
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if (cifs_pdu == NULL || session_key == NULL)
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return -EINVAL;
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if (cifs_pdu->Command == SMB_COM_NEGOTIATE)
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return 0;
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if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) {
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struct smb_com_lock_req *pSMB =
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(struct smb_com_lock_req *)cifs_pdu;
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if (pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE)
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return 0;
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}
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/* BB what if signatures are supposed to be on for session but
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server does not send one? BB */
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/* Do not need to verify session setups with signature "BSRSPYL " */
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if (memcmp(cifs_pdu->Signature.SecuritySignature, "BSRSPYL ", 8) == 0)
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cFYI(1, "dummy signature received for smb command 0x%x",
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cifs_pdu->Command);
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/* save off the origiginal signature so we can modify the smb and check
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its signature against what the server sent */
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memcpy(server_response_sig, cifs_pdu->Signature.SecuritySignature, 8);
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cifs_pdu->Signature.Sequence.SequenceNumber =
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cpu_to_le32(expected_sequence_number);
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cifs_pdu->Signature.Sequence.Reserved = 0;
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rc = cifs_calculate_signature(cifs_pdu, session_key,
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what_we_think_sig_should_be);
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if (rc)
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return rc;
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/* cifs_dump_mem("what we think it should be: ",
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what_we_think_sig_should_be, 16); */
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if (memcmp(server_response_sig, what_we_think_sig_should_be, 8))
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return -EACCES;
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else
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return 0;
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}
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/* We fill in key by putting in 40 byte array which was allocated by caller */
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int cifs_calculate_session_key(struct session_key *key, const char *rn,
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const char *password)
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{
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char temp_key[16];
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if ((key == NULL) || (rn == NULL))
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return -EINVAL;
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E_md4hash(password, temp_key);
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mdfour(key->data.ntlm, temp_key, 16);
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memcpy(key->data.ntlm+16, rn, CIFS_SESS_KEY_SIZE);
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key->len = 40;
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return 0;
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}
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#ifdef CONFIG_CIFS_WEAK_PW_HASH
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void calc_lanman_hash(const char *password, const char *cryptkey, bool encrypt,
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char *lnm_session_key)
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{
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int i;
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char password_with_pad[CIFS_ENCPWD_SIZE];
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memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
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if (password)
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strncpy(password_with_pad, password, CIFS_ENCPWD_SIZE);
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if (!encrypt && global_secflags & CIFSSEC_MAY_PLNTXT) {
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memset(lnm_session_key, 0, CIFS_SESS_KEY_SIZE);
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memcpy(lnm_session_key, password_with_pad,
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CIFS_ENCPWD_SIZE);
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return;
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}
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/* calculate old style session key */
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/* calling toupper is less broken than repeatedly
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calling nls_toupper would be since that will never
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work for UTF8, but neither handles multibyte code pages
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but the only alternative would be converting to UCS-16 (Unicode)
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(using a routine something like UniStrupr) then
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uppercasing and then converting back from Unicode - which
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would only worth doing it if we knew it were utf8. Basically
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utf8 and other multibyte codepages each need their own strupper
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function since a byte at a time will ont work. */
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for (i = 0; i < CIFS_ENCPWD_SIZE; i++)
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password_with_pad[i] = toupper(password_with_pad[i]);
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SMBencrypt(password_with_pad, cryptkey, lnm_session_key);
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/* clear password before we return/free memory */
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memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
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}
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#endif /* CIFS_WEAK_PW_HASH */
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/* Build a proper attribute value/target info pairs blob.
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* Fill in netbios and dns domain name and workstation name
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* and client time (total five av pairs and + one end of fields indicator.
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* Allocate domain name which gets freed when session struct is deallocated.
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*/
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static int
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build_avpair_blob(struct cifsSesInfo *ses, const struct nls_table *nls_cp)
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{
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unsigned int dlen;
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unsigned int wlen;
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unsigned int size = 6 * sizeof(struct ntlmssp2_name);
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__le64 curtime;
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char *defdmname = "WORKGROUP";
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unsigned char *blobptr;
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struct ntlmssp2_name *attrptr;
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if (!ses->domainName) {
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ses->domainName = kstrdup(defdmname, GFP_KERNEL);
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if (!ses->domainName)
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return -ENOMEM;
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}
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dlen = strlen(ses->domainName);
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wlen = strlen(ses->server->hostname);
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/* The length of this blob is a size which is
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* six times the size of a structure which holds name/size +
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* two times the unicode length of a domain name +
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* two times the unicode length of a server name +
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* size of a timestamp (which is 8 bytes).
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*/
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ses->tilen = size + 2 * (2 * dlen) + 2 * (2 * wlen) + 8;
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ses->tiblob = kzalloc(ses->tilen, GFP_KERNEL);
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if (!ses->tiblob) {
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ses->tilen = 0;
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cERROR(1, "Challenge target info allocation failure");
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return -ENOMEM;
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}
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blobptr = ses->tiblob;
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attrptr = (struct ntlmssp2_name *) blobptr;
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attrptr->type = cpu_to_le16(NTLMSSP_AV_NB_DOMAIN_NAME);
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attrptr->length = cpu_to_le16(2 * dlen);
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blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
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cifs_strtoUCS((__le16 *)blobptr, ses->domainName, dlen, nls_cp);
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blobptr += 2 * dlen;
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attrptr = (struct ntlmssp2_name *) blobptr;
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attrptr->type = cpu_to_le16(NTLMSSP_AV_NB_COMPUTER_NAME);
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attrptr->length = cpu_to_le16(2 * wlen);
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blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
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cifs_strtoUCS((__le16 *)blobptr, ses->server->hostname, wlen, nls_cp);
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blobptr += 2 * wlen;
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attrptr = (struct ntlmssp2_name *) blobptr;
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attrptr->type = cpu_to_le16(NTLMSSP_AV_DNS_DOMAIN_NAME);
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attrptr->length = cpu_to_le16(2 * dlen);
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blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
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cifs_strtoUCS((__le16 *)blobptr, ses->domainName, dlen, nls_cp);
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blobptr += 2 * dlen;
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attrptr = (struct ntlmssp2_name *) blobptr;
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attrptr->type = cpu_to_le16(NTLMSSP_AV_DNS_COMPUTER_NAME);
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attrptr->length = cpu_to_le16(2 * wlen);
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blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
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cifs_strtoUCS((__le16 *)blobptr, ses->server->hostname, wlen, nls_cp);
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blobptr += 2 * wlen;
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attrptr = (struct ntlmssp2_name *) blobptr;
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attrptr->type = cpu_to_le16(NTLMSSP_AV_TIMESTAMP);
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attrptr->length = cpu_to_le16(sizeof(__le64));
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blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
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curtime = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
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memcpy(blobptr, &curtime, sizeof(__le64));
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return 0;
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}
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/* Server has provided av pairs/target info in the type 2 challenge
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* packet and we have plucked it and stored within smb session.
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* We parse that blob here to find netbios domain name to be used
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* as part of ntlmv2 authentication (in Target String), if not already
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* specified on the command line.
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* If this function returns without any error but without fetching
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* domain name, authentication may fail against some server but
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* may not fail against other (those who are not very particular
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* about target string i.e. for some, just user name might suffice.
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*/
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static int
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find_domain_name(struct cifsSesInfo *ses)
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{
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unsigned int attrsize;
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unsigned int type;
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unsigned int onesize = sizeof(struct ntlmssp2_name);
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unsigned char *blobptr;
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unsigned char *blobend;
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struct ntlmssp2_name *attrptr;
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if (!ses->tilen || !ses->tiblob)
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return 0;
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blobptr = ses->tiblob;
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blobend = ses->tiblob + ses->tilen;
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while (blobptr + onesize < blobend) {
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attrptr = (struct ntlmssp2_name *) blobptr;
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type = le16_to_cpu(attrptr->type);
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if (type == NTLMSSP_AV_EOL)
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break;
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blobptr += 2; /* advance attr type */
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attrsize = le16_to_cpu(attrptr->length);
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blobptr += 2; /* advance attr size */
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if (blobptr + attrsize > blobend)
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break;
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if (type == NTLMSSP_AV_NB_DOMAIN_NAME) {
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if (!attrsize)
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break;
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if (!ses->domainName) {
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struct nls_table *default_nls;
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ses->domainName =
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kmalloc(attrsize + 1, GFP_KERNEL);
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if (!ses->domainName)
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return -ENOMEM;
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default_nls = load_nls_default();
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cifs_from_ucs2(ses->domainName,
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(__le16 *)blobptr, attrsize, attrsize,
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default_nls, false);
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unload_nls(default_nls);
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break;
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}
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}
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blobptr += attrsize; /* advance attr value */
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}
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return 0;
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}
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static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
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const struct nls_table *nls_cp)
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{
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int rc = 0;
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int len;
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char nt_hash[16];
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struct HMACMD5Context *pctxt;
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wchar_t *user;
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wchar_t *domain;
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pctxt = kmalloc(sizeof(struct HMACMD5Context), GFP_KERNEL);
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if (pctxt == NULL)
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return -ENOMEM;
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/* calculate md4 hash of password */
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E_md4hash(ses->password, nt_hash);
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/* convert Domainname to unicode and uppercase */
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hmac_md5_init_limK_to_64(nt_hash, 16, pctxt);
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/* convert ses->userName to unicode and uppercase */
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len = strlen(ses->userName);
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user = kmalloc(2 + (len * 2), GFP_KERNEL);
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if (user == NULL)
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goto calc_exit_2;
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len = cifs_strtoUCS((__le16 *)user, ses->userName, len, nls_cp);
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UniStrupr(user);
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hmac_md5_update((char *)user, 2*len, pctxt);
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/* convert ses->domainName to unicode and uppercase */
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if (ses->domainName) {
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len = strlen(ses->domainName);
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domain = kmalloc(2 + (len * 2), GFP_KERNEL);
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if (domain == NULL)
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goto calc_exit_1;
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len = cifs_strtoUCS((__le16 *)domain, ses->domainName, len,
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nls_cp);
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/* the following line was removed since it didn't work well
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with lower cased domain name that passed as an option.
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Maybe converting the domain name earlier makes sense */
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/* UniStrupr(domain); */
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hmac_md5_update((char *)domain, 2*len, pctxt);
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kfree(domain);
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}
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calc_exit_1:
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kfree(user);
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calc_exit_2:
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/* BB FIXME what about bytes 24 through 40 of the signing key?
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compare with the NTLM example */
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hmac_md5_final(ses->server->ntlmv2_hash, pctxt);
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kfree(pctxt);
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return rc;
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}
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int
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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 MAC key for NTLMv2 */
|
|
hmac_md5_init_limK_to_64(ses->server->ntlmv2_hash, 16, &context);
|
|
hmac_md5_update(resp_buf, 16, &context);
|
|
hmac_md5_final(ses->server->session_key.data.ntlmv2.key, &context);
|
|
|
|
memcpy(&ses->server->session_key.data.ntlmv2.resp, resp_buf,
|
|
sizeof(struct ntlmv2_resp));
|
|
ses->server->session_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->server->cryptKey, 8);
|
|
hmac_md5_init_limK_to_64(ses->server->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); */
|
|
}
|