fs/cifs/cifsencrypt.c

   1 /*
   2  *   fs/cifs/cifsencrypt.c
   3  *
   4  *   Copyright (C) International Business Machines  Corp., 2003
   5  *   Author(s): Steve French (sfrench@us.ibm.com)
   6  *
   7  *   This library is free software; you can redistribute it and/or modify
   8  *   it under the terms of the GNU Lesser General Public License as published
   9  *   by the Free Software Foundation; either version 2.1 of the License, or
  10  *   (at your option) any later version.
  11  *
  12  *   This library is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  15  *   the GNU Lesser General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU Lesser General Public License
  18  *   along with this library; if not, write to the Free Software
  19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <linux/fs.h>
  23 #include "cifspdu.h"
  24 #include "cifsglob.h"
  25 #include "cifs_debug.h"
  26 #include "md5.h"
  27 #include "cifs_unicode.h"
  28 #include "cifsproto.h"
  29
  30 /* Calculate and return the CIFS signature based on the mac key and the smb pdu */
  31 /* the 16 byte signature must be allocated by the caller  */
  32 /* Note we only use the 1st eight bytes */
  33 /* Note that the smb header signature field on input contains the
  34         sequence number before this function is called */
  35
  36 extern void mdfour(unsigned char *out, unsigned char *in, int n);
  37 extern void E_md4hash(const unsigned char *passwd, unsigned char *p16);
  38
  39 static int cifs_calculate_signature(const struct smb_hdr * cifs_pdu, const char * key, char * signature)
  40 {
  41         struct  MD5Context context;
  42
  43         if((cifs_pdu == NULL) || (signature == NULL))
  44                 return -EINVAL;
  45
  46         MD5Init(&context);
  47         MD5Update(&context,key,CIFS_SESSION_KEY_SIZE+16);
  48         MD5Update(&context,cifs_pdu->Protocol,cifs_pdu->smb_buf_length);
  49         MD5Final(signature,&context);
  50         return 0;
  51 }
  52
  53 int cifs_sign_smb(struct smb_hdr * cifs_pdu, struct cifsSesInfo * ses,
  54         __u32 * pexpected_response_sequence_number)
  55 {
  56         int rc = 0;
  57         char smb_signature[20];
  58
  59         /* BB remember to initialize sequence number elsewhere and initialize mac_signing key elsewhere BB */
  60         /* BB remember to add code to save expected sequence number in midQ entry BB */
  61
  62         if((cifs_pdu == NULL) || (ses == NULL))
  63                 return -EINVAL;
  64
  65         if((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
  66                 return rc;
  67
  68         spin_lock(&GlobalMid_Lock);
  69         cifs_pdu->Signature.Sequence.SequenceNumber = cpu_to_le32(ses->sequence_number);
  70         cifs_pdu->Signature.Sequence.Reserved = 0;
  71
  72         *pexpected_response_sequence_number = ses->sequence_number++;
  73         ses->sequence_number++;
  74         spin_unlock(&GlobalMid_Lock);
  75
  76         rc = cifs_calculate_signature(cifs_pdu, ses->mac_signing_key,smb_signature);
  77         if(rc)
  78                 memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
  79         else
  80                 memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
  81
  82         return rc;
  83 }
  84
  85 int cifs_verify_signature(struct smb_hdr * cifs_pdu, const char * mac_key,
  86         __u32 expected_sequence_number)
  87 {
  88         unsigned int rc;
  89         char server_response_sig[8];
  90         char what_we_think_sig_should_be[20];
  91
  92         if((cifs_pdu == NULL) || (mac_key == NULL))
  93                 return -EINVAL;
  94
  95         if (cifs_pdu->Command == SMB_COM_NEGOTIATE)
  96                 return 0;
  97
  98         if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) {
  99                 struct smb_com_lock_req * pSMB = (struct smb_com_lock_req *)cifs_pdu;
 100             if(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE)
 101                         return 0;
 102         }
 103
 104         /* BB what if signatures are supposed to be on for session but server does not
 105                 send one? BB */
 106
 107         /* Do not need to verify session setups with signature "BSRSPYL "  */
 108         if(memcmp(cifs_pdu->Signature.SecuritySignature,"BSRSPYL ",8)==0)
 109                 cFYI(1,("dummy signature received for smb command 0x%x",cifs_pdu->Command));
 110
 111         /* save off the origiginal signature so we can modify the smb and check
 112                 its signature against what the server sent */
 113         memcpy(server_response_sig,cifs_pdu->Signature.SecuritySignature,8);
 114
 115         cifs_pdu->Signature.Sequence.SequenceNumber = cpu_to_le32(expected_sequence_number);
 116         cifs_pdu->Signature.Sequence.Reserved = 0;
 117
 118         rc = cifs_calculate_signature(cifs_pdu, mac_key,
 119                 what_we_think_sig_should_be);
 120
 121         if(rc)
 122                 return rc;
 123
 124
 125 /*      cifs_dump_mem("what we think it should be: ",what_we_think_sig_should_be,16); */
 126
 127         if(memcmp(server_response_sig, what_we_think_sig_should_be, 8))
 128                 return -EACCES;
 129         else
 130                 return 0;
 131
 132 }
 133
 134 /* We fill in key by putting in 40 byte array which was allocated by caller */
 135 int cifs_calculate_mac_key(char * key, const char * rn, const char * password)
 136 {
 137         char temp_key[16];
 138         if ((key == NULL) || (rn == NULL))
 139                 return -EINVAL;
 140
 141         E_md4hash(password, temp_key);
 142         mdfour(key,temp_key,16);
 143         memcpy(key+16,rn, CIFS_SESSION_KEY_SIZE);
 144         return 0;
 145 }
 146
 147 int CalcNTLMv2_partial_mac_key(struct cifsSesInfo * ses, struct nls_table * nls_info)
 148 {
 149         char temp_hash[16];
 150         struct HMACMD5Context ctx;
 151         char * ucase_buf;
 152         wchar_t * unicode_buf;
 153         unsigned int i,user_name_len,dom_name_len;
 154
 155         if(ses == NULL)
 156                 return -EINVAL;
 157
 158         E_md4hash(ses->password, temp_hash);
 159
 160         hmac_md5_init_limK_to_64(temp_hash, 16, &ctx);
 161         user_name_len = strlen(ses->userName);
 162         if(user_name_len > MAX_USERNAME_SIZE)
 163                 return -EINVAL;
 164         dom_name_len = strlen(ses->domainName);
 165         if(dom_name_len > MAX_USERNAME_SIZE)
 166                 return -EINVAL;
 167
 168         ucase_buf = kmalloc((MAX_USERNAME_SIZE+1), GFP_KERNEL);
 169         if(ucase_buf == NULL)
 170                 return -ENOMEM;
 171         unicode_buf = kmalloc((MAX_USERNAME_SIZE+1)*4, GFP_KERNEL);
 172         if(unicode_buf == NULL) {
 173                 kfree(ucase_buf);
 174                 return -ENOMEM;
 175         }
 176
 177         for(i=0;i<user_name_len;i++)
 178                 ucase_buf[i] = nls_info->charset2upper[(int)ses->userName[i]];
 179         ucase_buf[i] = 0;
 180         user_name_len = cifs_strtoUCS(unicode_buf, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
 181         unicode_buf[user_name_len] = 0;
 182         user_name_len++;
 183
 184         for(i=0;i<dom_name_len;i++)
 185                 ucase_buf[i] = nls_info->charset2upper[(int)ses->domainName[i]];
 186         ucase_buf[i] = 0;
 187         dom_name_len = cifs_strtoUCS(unicode_buf+user_name_len, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
 188
 189         unicode_buf[user_name_len + dom_name_len] = 0;
 190         hmac_md5_update((const unsigned char *) unicode_buf,
 191                 (user_name_len+dom_name_len)*2,&ctx);
 192
 193         hmac_md5_final(ses->mac_signing_key,&ctx);
 194         kfree(ucase_buf);
 195         kfree(unicode_buf);
 196         return 0;
 197 }
 198 void CalcNTLMv2_response(const struct cifsSesInfo * ses,char * v2_session_response)
 199 {
 200         struct HMACMD5Context context;
 201         memcpy(v2_session_response + 8, ses->server->cryptKey,8);
 202         /* gen_blob(v2_session_response + 16); */
 203         hmac_md5_init_limK_to_64(ses->mac_signing_key, 16, &context);
 204
 205         hmac_md5_update(ses->server->cryptKey,8,&context);
 206 /*      hmac_md5_update(v2_session_response+16)client thing,8,&context); */ /* BB fix */
 207
 208         hmac_md5_final(v2_session_response,&context);
 209 }