fs/cifs/cifsencrypt.c

   1 /*
   2  *   fs/cifs/cifsencrypt.c
   3  *
   4  *   Copyright (C) International Business Machines  Corp., 2005
   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 TCP_Server_Info * server,
  54         __u32 * pexpected_response_sequence_number)
  55 {
  56         int rc = 0;
  57         char smb_signature[20];
  58
  59         if((cifs_pdu == NULL) || (server == NULL))
  60                 return -EINVAL;
  61
  62         if((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
  63                 return rc;
  64
  65         spin_lock(&GlobalMid_Lock);
  66         cifs_pdu->Signature.Sequence.SequenceNumber = cpu_to_le32(server->sequence_number);
  67         cifs_pdu->Signature.Sequence.Reserved = 0;
  68
  69         *pexpected_response_sequence_number = server->sequence_number++;
  70         server->sequence_number++;
  71         spin_unlock(&GlobalMid_Lock);
  72
  73         rc = cifs_calculate_signature(cifs_pdu, server->mac_signing_key,smb_signature);
  74         if(rc)
  75                 memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
  76         else
  77                 memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
  78
  79         return rc;
  80 }
  81
  82 static int cifs_calc_signature2(const struct kvec * iov, int n_vec,
  83                                 const char * key, char * signature)
  84 {
  85         struct  MD5Context context;
  86         int i;
  87
  88         if((iov == NULL) || (signature == NULL))
  89                 return -EINVAL;
  90
  91         MD5Init(&context);
  92         MD5Update(&context,key,CIFS_SESSION_KEY_SIZE+16);
  93         for(i=0;i<n_vec;i++) {
  94                 if(iov[i].iov_base == NULL) {
  95                         cERROR(1,("null iovec entry"));
  96                         return -EIO;
  97                 } else if(iov[i].iov_len == 0)
  98                         break; /* bail out if we are sent nothing to sign */
  99                 /* The first entry includes a length field (which does not get
 100                    signed that occupies the first 4 bytes before the header */
 101                 if(i==0) {
 102                         if (iov[0].iov_len <= 8 ) /* cmd field at offset 9 */
 103                                 break; /* nothing to sign or corrupt header */
 104                         MD5Update(&context,iov[0].iov_base+4, iov[0].iov_len-4);
 105                 } else
 106                         MD5Update(&context,iov[i].iov_base, iov[i].iov_len);
 107         }
 108
 109         MD5Final(signature,&context);
 110
 111         return 0;
 112 }
 113
 114
 115 int cifs_sign_smb2(struct kvec * iov, int n_vec, struct TCP_Server_Info *server,
 116                    __u32 * pexpected_response_sequence_number)
 117 {
 118         int rc = 0;
 119         char smb_signature[20];
 120         struct smb_hdr * cifs_pdu = iov[0].iov_base;
 121
 122         if((cifs_pdu == NULL) || (server == NULL))
 123                 return -EINVAL;
 124
 125         if((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
 126                 return rc;
 127
 128         spin_lock(&GlobalMid_Lock);
 129         cifs_pdu->Signature.Sequence.SequenceNumber =
 130                                 cpu_to_le32(server->sequence_number);
 131         cifs_pdu->Signature.Sequence.Reserved = 0;
 132
 133         *pexpected_response_sequence_number = server->sequence_number++;
 134         server->sequence_number++;
 135         spin_unlock(&GlobalMid_Lock);
 136
 137         rc = cifs_calc_signature2(iov, n_vec, server->mac_signing_key,
 138                                       smb_signature);
 139         if(rc)
 140                 memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
 141         else
 142                 memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
 143
 144         return rc;
 145
 146 }
 147
 148 int cifs_verify_signature(struct smb_hdr * cifs_pdu, const char * mac_key,
 149         __u32 expected_sequence_number)
 150 {
 151         unsigned int rc;
 152         char server_response_sig[8];
 153         char what_we_think_sig_should_be[20];
 154
 155         if((cifs_pdu == NULL) || (mac_key == NULL))
 156                 return -EINVAL;
 157
 158         if (cifs_pdu->Command == SMB_COM_NEGOTIATE)
 159                 return 0;
 160
 161         if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) {
 162                 struct smb_com_lock_req * pSMB = (struct smb_com_lock_req *)cifs_pdu;
 163             if(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE)
 164                         return 0;
 165         }
 166
 167         /* BB what if signatures are supposed to be on for session but server does not
 168                 send one? BB */
 169
 170         /* Do not need to verify session setups with signature "BSRSPYL "  */
 171         if(memcmp(cifs_pdu->Signature.SecuritySignature,"BSRSPYL ",8)==0)
 172                 cFYI(1,("dummy signature received for smb command 0x%x",cifs_pdu->Command));
 173
 174         /* save off the origiginal signature so we can modify the smb and check
 175                 its signature against what the server sent */
 176         memcpy(server_response_sig,cifs_pdu->Signature.SecuritySignature,8);
 177
 178         cifs_pdu->Signature.Sequence.SequenceNumber = cpu_to_le32(expected_sequence_number);
 179         cifs_pdu->Signature.Sequence.Reserved = 0;
 180
 181         rc = cifs_calculate_signature(cifs_pdu, mac_key,
 182                 what_we_think_sig_should_be);
 183
 184         if(rc)
 185                 return rc;
 186
 187
 188 /*      cifs_dump_mem("what we think it should be: ",what_we_think_sig_should_be,16); */
 189
 190         if(memcmp(server_response_sig, what_we_think_sig_should_be, 8))
 191                 return -EACCES;
 192         else
 193                 return 0;
 194
 195 }
 196
 197 /* We fill in key by putting in 40 byte array which was allocated by caller */
 198 int cifs_calculate_mac_key(char * key, const char * rn, const char * password)
 199 {
 200         char temp_key[16];
 201         if ((key == NULL) || (rn == NULL))
 202                 return -EINVAL;
 203
 204         E_md4hash(password, temp_key);
 205         mdfour(key,temp_key,16);
 206         memcpy(key+16,rn, CIFS_SESSION_KEY_SIZE);
 207         return 0;
 208 }
 209
 210 int CalcNTLMv2_partial_mac_key(struct cifsSesInfo * ses, struct nls_table * nls_info)
 211 {
 212         char temp_hash[16];
 213         struct HMACMD5Context ctx;
 214         char * ucase_buf;
 215         __le16 * unicode_buf;
 216         unsigned int i,user_name_len,dom_name_len;
 217
 218         if(ses == NULL)
 219                 return -EINVAL;
 220
 221         E_md4hash(ses->password, temp_hash);
 222
 223         hmac_md5_init_limK_to_64(temp_hash, 16, &ctx);
 224         user_name_len = strlen(ses->userName);
 225         if(user_name_len > MAX_USERNAME_SIZE)
 226                 return -EINVAL;
 227         dom_name_len = strlen(ses->domainName);
 228         if(dom_name_len > MAX_USERNAME_SIZE)
 229                 return -EINVAL;
 230
 231         ucase_buf = kmalloc((MAX_USERNAME_SIZE+1), GFP_KERNEL);
 232         if(ucase_buf == NULL)
 233                 return -ENOMEM;
 234         unicode_buf = kmalloc((MAX_USERNAME_SIZE+1)*4, GFP_KERNEL);
 235         if(unicode_buf == NULL) {
 236                 kfree(ucase_buf);
 237                 return -ENOMEM;
 238         }
 239
 240         for(i=0;i<user_name_len;i++)
 241                 ucase_buf[i] = nls_info->charset2upper[(int)ses->userName[i]];
 242         ucase_buf[i] = 0;
 243         user_name_len = cifs_strtoUCS(unicode_buf, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
 244         unicode_buf[user_name_len] = 0;
 245         user_name_len++;
 246
 247         for(i=0;i<dom_name_len;i++)
 248                 ucase_buf[i] = nls_info->charset2upper[(int)ses->domainName[i]];
 249         ucase_buf[i] = 0;
 250         dom_name_len = cifs_strtoUCS(unicode_buf+user_name_len, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
 251
 252         unicode_buf[user_name_len + dom_name_len] = 0;
 253         hmac_md5_update((const unsigned char *) unicode_buf,
 254                 (user_name_len+dom_name_len)*2,&ctx);
 255
 256         hmac_md5_final(ses->server->mac_signing_key,&ctx);
 257         kfree(ucase_buf);
 258         kfree(unicode_buf);
 259         return 0;
 260 }
 261 void CalcNTLMv2_response(const struct cifsSesInfo * ses,char * v2_session_response)
 262 {
 263         struct HMACMD5Context context;
 264         memcpy(v2_session_response + 8, ses->server->cryptKey,8);
 265         /* gen_blob(v2_session_response + 16); */
 266         hmac_md5_init_limK_to_64(ses->server->mac_signing_key, 16, &context);
 267
 268         hmac_md5_update(ses->server->cryptKey,8,&context);
 269 /*      hmac_md5_update(v2_session_response+16)client thing,8,&context); */ /* BB fix */
 270
 271         hmac_md5_final(v2_session_response,&context);
 272 }