fs/cifs/cifsencrypt.c

   1 /*
   2  *   fs/cifs/cifsencrypt.c
   3  *
   4  *   Copyright (C) International Business Machines  Corp., 2005,2006
   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,
  40                                     const char * key, char * signature)
  41 {
  42         struct  MD5Context context;
  43
  44         if((cifs_pdu == NULL) || (signature == NULL))
  45                 return -EINVAL;
  46
  47         MD5Init(&context);
  48         MD5Update(&context,key,CIFS_SESSION_KEY_SIZE+16);
  49         MD5Update(&context,cifs_pdu->Protocol,cifs_pdu->smb_buf_length);
  50         MD5Final(signature,&context);
  51         return 0;
  52 }
  53
  54 int cifs_sign_smb(struct smb_hdr * cifs_pdu, struct TCP_Server_Info * server,
  55         __u32 * pexpected_response_sequence_number)
  56 {
  57         int rc = 0;
  58         char smb_signature[20];
  59
  60         if((cifs_pdu == NULL) || (server == NULL))
  61                 return -EINVAL;
  62
  63         if((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
  64                 return rc;
  65
  66         spin_lock(&GlobalMid_Lock);
  67         cifs_pdu->Signature.Sequence.SequenceNumber = cpu_to_le32(server->sequence_number);
  68         cifs_pdu->Signature.Sequence.Reserved = 0;
  69
  70         *pexpected_response_sequence_number = server->sequence_number++;
  71         server->sequence_number++;
  72         spin_unlock(&GlobalMid_Lock);
  73
  74         rc = cifs_calculate_signature(cifs_pdu, server->mac_signing_key,smb_signature);
  75         if(rc)
  76                 memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
  77         else
  78                 memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
  79
  80         return rc;
  81 }
  82
  83 static int cifs_calc_signature2(const struct kvec * iov, int n_vec,
  84                                 const char * key, char * signature)
  85 {
  86         struct  MD5Context context;
  87         int i;
  88
  89         if((iov == NULL) || (signature == NULL))
  90                 return -EINVAL;
  91
  92         MD5Init(&context);
  93         MD5Update(&context,key,CIFS_SESSION_KEY_SIZE+16);
  94         for(i=0;i<n_vec;i++) {
  95                 if(iov[i].iov_base == NULL) {
  96                         cERROR(1,("null iovec entry"));
  97                         return -EIO;
  98                 } else if(iov[i].iov_len == 0)
  99                         break; /* bail out if we are sent nothing to sign */
 100                 /* The first entry includes a length field (which does not get
 101                    signed that occupies the first 4 bytes before the header */
 102                 if(i==0) {
 103                         if (iov[0].iov_len <= 8 ) /* cmd field at offset 9 */
 104                                 break; /* nothing to sign or corrupt header */
 105                         MD5Update(&context,iov[0].iov_base+4, iov[0].iov_len-4);
 106                 } else
 107                         MD5Update(&context,iov[i].iov_base, iov[i].iov_len);
 108         }
 109
 110         MD5Final(signature,&context);
 111
 112         return 0;
 113 }
 114
 115
 116 int cifs_sign_smb2(struct kvec * iov, int n_vec, struct TCP_Server_Info *server,
 117                    __u32 * pexpected_response_sequence_number)
 118 {
 119         int rc = 0;
 120         char smb_signature[20];
 121         struct smb_hdr * cifs_pdu = iov[0].iov_base;
 122
 123         if((cifs_pdu == NULL) || (server == NULL))
 124                 return -EINVAL;
 125
 126         if((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
 127                 return rc;
 128
 129         spin_lock(&GlobalMid_Lock);
 130         cifs_pdu->Signature.Sequence.SequenceNumber =
 131                                 cpu_to_le32(server->sequence_number);
 132         cifs_pdu->Signature.Sequence.Reserved = 0;
 133
 134         *pexpected_response_sequence_number = server->sequence_number++;
 135         server->sequence_number++;
 136         spin_unlock(&GlobalMid_Lock);
 137
 138         rc = cifs_calc_signature2(iov, n_vec, server->mac_signing_key,
 139                                       smb_signature);
 140         if(rc)
 141                 memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
 142         else
 143                 memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
 144
 145         return rc;
 146
 147 }
 148
 149 int cifs_verify_signature(struct smb_hdr * cifs_pdu, const char * mac_key,
 150         __u32 expected_sequence_number)
 151 {
 152         unsigned int rc;
 153         char server_response_sig[8];
 154         char what_we_think_sig_should_be[20];
 155
 156         if((cifs_pdu == NULL) || (mac_key == NULL))
 157                 return -EINVAL;
 158
 159         if (cifs_pdu->Command == SMB_COM_NEGOTIATE)
 160                 return 0;
 161
 162         if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) {
 163                 struct smb_com_lock_req * pSMB = (struct smb_com_lock_req *)cifs_pdu;
 164             if(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE)
 165                         return 0;
 166         }
 167
 168         /* BB what if signatures are supposed to be on for session but server does not
 169                 send one? BB */
 170
 171         /* Do not need to verify session setups with signature "BSRSPYL "  */
 172         if(memcmp(cifs_pdu->Signature.SecuritySignature,"BSRSPYL ",8)==0)
 173                 cFYI(1,("dummy signature received for smb command 0x%x",cifs_pdu->Command));
 174
 175         /* save off the origiginal signature so we can modify the smb and check
 176                 its signature against what the server sent */
 177         memcpy(server_response_sig,cifs_pdu->Signature.SecuritySignature,8);
 178
 179         cifs_pdu->Signature.Sequence.SequenceNumber = cpu_to_le32(expected_sequence_number);
 180         cifs_pdu->Signature.Sequence.Reserved = 0;
 181
 182         rc = cifs_calculate_signature(cifs_pdu, mac_key,
 183                 what_we_think_sig_should_be);
 184
 185         if(rc)
 186                 return rc;
 187
 188
 189 /*      cifs_dump_mem("what we think it should be: ",what_we_think_sig_should_be,16); */
 190
 191         if(memcmp(server_response_sig, what_we_think_sig_should_be, 8))
 192                 return -EACCES;
 193         else
 194                 return 0;
 195
 196 }
 197
 198 /* We fill in key by putting in 40 byte array which was allocated by caller */
 199 int cifs_calculate_mac_key(char * key, const char * rn, const char * password)
 200 {
 201         char temp_key[16];
 202         if ((key == NULL) || (rn == NULL))
 203                 return -EINVAL;
 204
 205         E_md4hash(password, temp_key);
 206         mdfour(key,temp_key,16);
 207         memcpy(key+16,rn, CIFS_SESSION_KEY_SIZE);
 208         return 0;
 209 }
 210
 211 int CalcNTLMv2_partial_mac_key(struct cifsSesInfo * ses, struct nls_table * nls_info)
 212 {
 213         char temp_hash[16];
 214         struct HMACMD5Context ctx;
 215         char * ucase_buf;
 216         __le16 * unicode_buf;
 217         unsigned int i,user_name_len,dom_name_len;
 218
 219         if(ses == NULL)
 220                 return -EINVAL;
 221
 222         E_md4hash(ses->password, temp_hash);
 223
 224         hmac_md5_init_limK_to_64(temp_hash, 16, &ctx);
 225         user_name_len = strlen(ses->userName);
 226         if(user_name_len > MAX_USERNAME_SIZE)
 227                 return -EINVAL;
 228         dom_name_len = strlen(ses->domainName);
 229         if(dom_name_len > MAX_USERNAME_SIZE)
 230                 return -EINVAL;
 231
 232         ucase_buf = kmalloc((MAX_USERNAME_SIZE+1), GFP_KERNEL);
 233         if(ucase_buf == NULL)
 234                 return -ENOMEM;
 235         unicode_buf = kmalloc((MAX_USERNAME_SIZE+1)*4, GFP_KERNEL);
 236         if(unicode_buf == NULL) {
 237                 kfree(ucase_buf);
 238                 return -ENOMEM;
 239         }
 240
 241         for(i=0;i<user_name_len;i++)
 242                 ucase_buf[i] = nls_info->charset2upper[(int)ses->userName[i]];
 243         ucase_buf[i] = 0;
 244         user_name_len = cifs_strtoUCS(unicode_buf, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
 245         unicode_buf[user_name_len] = 0;
 246         user_name_len++;
 247
 248         for(i=0;i<dom_name_len;i++)
 249                 ucase_buf[i] = nls_info->charset2upper[(int)ses->domainName[i]];
 250         ucase_buf[i] = 0;
 251         dom_name_len = cifs_strtoUCS(unicode_buf+user_name_len, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
 252
 253         unicode_buf[user_name_len + dom_name_len] = 0;
 254         hmac_md5_update((const unsigned char *) unicode_buf,
 255                 (user_name_len+dom_name_len)*2,&ctx);
 256
 257         hmac_md5_final(ses->server->mac_signing_key,&ctx);
 258         kfree(ucase_buf);
 259         kfree(unicode_buf);
 260         return 0;
 261 }
 262 void CalcNTLMv2_response(const struct cifsSesInfo * ses,char * v2_session_response)
 263 {
 264         struct HMACMD5Context context;
 265         memcpy(v2_session_response + 8, ses->server->cryptKey,8);
 266         /* gen_blob(v2_session_response + 16); */
 267         hmac_md5_init_limK_to_64(ses->server->mac_signing_key, 16, &context);
 268
 269         hmac_md5_update(ses->server->cryptKey,8,&context);
 270 /*      hmac_md5_update(v2_session_response+16)client thing,8,&context); */ /* BB fix */
 271
 272         hmac_md5_final(v2_session_response,&context);
 273         cifs_dump_mem("v2_sess_rsp: ", v2_session_response, 32); /* BB removeme BB */
 274 }