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
  29 /* Calculate and return the CIFS signature based on the mac key and the smb pdu */
  30 /* the 16 byte signature must be allocated by the caller  */
  31 /* Note we only use the 1st eight bytes */
  32 /* Note that the smb header signature field on input contains the
  33         sequence number before this function is called */
  34
  35 extern void mdfour(unsigned char *out, unsigned char *in, int n);
  36 extern void E_md4hash(const unsigned char *passwd, unsigned char *p16);
  37
  38 static int cifs_calculate_signature(const struct smb_hdr * cifs_pdu, const char * key, char * signature)
  39 {
  40         struct  MD5Context context;
  41
  42         if((cifs_pdu == NULL) || (signature == NULL))
  43                 return -EINVAL;
  44
  45         MD5Init(&context);
  46         MD5Update(&context,key,CIFS_SESSION_KEY_SIZE+16);
  47         MD5Update(&context,cifs_pdu->Protocol,cifs_pdu->smb_buf_length);
  48         MD5Final(signature,&context);
  49         return 0;
  50 }
  51
  52 int cifs_sign_smb(struct smb_hdr * cifs_pdu, struct cifsSesInfo * ses,
  53         __u32 * pexpected_response_sequence_number)
  54 {
  55         int rc = 0;
  56         char smb_signature[20];
  57
  58         /* BB remember to initialize sequence number elsewhere and initialize mac_signing key elsewhere BB */
  59         /* BB remember to add code to save expected sequence number in midQ entry BB */
  60
  61         if((cifs_pdu == NULL) || (ses == NULL))
  62                 return -EINVAL;
  63
  64         if((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
  65                 return rc;
  66
  67         spin_lock(&GlobalMid_Lock);
  68         cifs_pdu->Signature.Sequence.SequenceNumber = cpu_to_le32(ses->sequence_number);
  69         cifs_pdu->Signature.Sequence.Reserved = 0;
  70
  71         *pexpected_response_sequence_number = ses->sequence_number++;
  72         ses->sequence_number++;
  73         spin_unlock(&GlobalMid_Lock);
  74
  75         rc = cifs_calculate_signature(cifs_pdu, ses->mac_signing_key,smb_signature);
  76         if(rc)
  77                 memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
  78         else
  79                 memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
  80
  81         return rc;
  82 }
  83
  84 int cifs_verify_signature(struct smb_hdr * cifs_pdu, const char * mac_key,
  85         __u32 expected_sequence_number)
  86 {
  87         unsigned int rc;
  88         char server_response_sig[8];
  89         char what_we_think_sig_should_be[20];
  90
  91         if((cifs_pdu == NULL) || (mac_key == NULL))
  92                 return -EINVAL;
  93
  94         if (cifs_pdu->Command == SMB_COM_NEGOTIATE)
  95                 return 0;
  96
  97         if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) {
  98                 struct smb_com_lock_req * pSMB = (struct smb_com_lock_req *)cifs_pdu;
  99             if(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE)
 100                         return 0;
 101         }
 102
 103         /* BB what if signatures are supposed to be on for session but server does not
 104                 send one? BB */
 105
 106         /* Do not need to verify session setups with signature "BSRSPYL "  */
 107         if(memcmp(cifs_pdu->Signature.SecuritySignature,"BSRSPYL ",8)==0)
 108                 cFYI(1,("dummy signature received for smb command 0x%x",cifs_pdu->Command));
 109
 110         /* save off the origiginal signature so we can modify the smb and check
 111                 its signature against what the server sent */
 112         memcpy(server_response_sig,cifs_pdu->Signature.SecuritySignature,8);
 113
 114         cifs_pdu->Signature.Sequence.SequenceNumber = cpu_to_le32(expected_sequence_number);
 115         cifs_pdu->Signature.Sequence.Reserved = 0;
 116
 117         rc = cifs_calculate_signature(cifs_pdu, mac_key,
 118                 what_we_think_sig_should_be);
 119
 120         if(rc)
 121                 return rc;
 122
 123
 124 /*      cifs_dump_mem("what we think it should be: ",what_we_think_sig_should_be,16); */
 125
 126         if(memcmp(server_response_sig, what_we_think_sig_should_be, 8))
 127                 return -EACCES;
 128         else
 129                 return 0;
 130
 131 }
 132
 133 /* We fill in key by putting in 40 byte array which was allocated by caller */
 134 int cifs_calculate_mac_key(char * key, const char * rn, const char * password)
 135 {
 136         char temp_key[16];
 137         if ((key == NULL) || (rn == NULL))
 138                 return -EINVAL;
 139
 140         E_md4hash(password, temp_key);
 141         mdfour(key,temp_key,16);
 142         memcpy(key+16,rn, CIFS_SESSION_KEY_SIZE);
 143         return 0;
 144 }
 145
 146 int CalcNTLMv2_partial_mac_key(struct cifsSesInfo * ses, struct nls_table * nls_info)
 147 {
 148         char temp_hash[16];
 149         struct HMACMD5Context ctx;
 150         char * ucase_buf;
 151         wchar_t * unicode_buf;
 152         unsigned int i,user_name_len,dom_name_len;
 153
 154         if(ses == NULL)
 155                 return -EINVAL;
 156
 157         E_md4hash(ses->password, temp_hash);
 158
 159         hmac_md5_init_limK_to_64(temp_hash, 16, &ctx);
 160         user_name_len = strlen(ses->userName);
 161         if(user_name_len > MAX_USERNAME_SIZE)
 162                 return -EINVAL;
 163         dom_name_len = strlen(ses->domainName);
 164         if(dom_name_len > MAX_USERNAME_SIZE)
 165                 return -EINVAL;
 166
 167         ucase_buf = kmalloc((MAX_USERNAME_SIZE+1), GFP_KERNEL);
 168         if(ucase_buf == NULL)
 169                 return -ENOMEM;
 170         unicode_buf = kmalloc((MAX_USERNAME_SIZE+1)*4, GFP_KERNEL);
 171         if(unicode_buf == NULL) {
 172                 kfree(ucase_buf);
 173                 return -ENOMEM;
 174         }
 175
 176         for(i=0;i<user_name_len;i++)
 177                 ucase_buf[i] = nls_info->charset2upper[(int)ses->userName[i]];
 178         ucase_buf[i] = 0;
 179         user_name_len = cifs_strtoUCS(unicode_buf, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
 180         unicode_buf[user_name_len] = 0;
 181         user_name_len++;
 182
 183         for(i=0;i<dom_name_len;i++)
 184                 ucase_buf[i] = nls_info->charset2upper[(int)ses->domainName[i]];
 185         ucase_buf[i] = 0;
 186         dom_name_len = cifs_strtoUCS(unicode_buf+user_name_len, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
 187
 188         unicode_buf[user_name_len + dom_name_len] = 0;
 189         hmac_md5_update((const unsigned char *) unicode_buf,
 190                 (user_name_len+dom_name_len)*2,&ctx);
 191
 192         hmac_md5_final(ses->mac_signing_key,&ctx);
 193         kfree(ucase_buf);
 194         kfree(unicode_buf);
 195         return 0;
 196 }
 197 void CalcNTLMv2_response(const struct cifsSesInfo * ses,char * v2_session_response)
 198 {
 199         struct HMACMD5Context context;
 200         memcpy(v2_session_response + 8, ses->server->cryptKey,8);
 201         /* gen_blob(v2_session_response + 16); */
 202         hmac_md5_init_limK_to_64(ses->mac_signing_key, 16, &context);
 203
 204         hmac_md5_update(ses->server->cryptKey,8,&context);
 205 /*      hmac_md5_update(v2_session_response+16)client thing,8,&context); */ /* BB fix */
 206
 207         hmac_md5_final(v2_session_response,&context);
 208 }