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 #include <linux/ctype.h>
  30 #include <linux/random.h>
  31
  32 /* Calculate and return the CIFS signature based on the mac key and the smb pdu */
  33 /* the 16 byte signature must be allocated by the caller  */
  34 /* Note we only use the 1st eight bytes */
  35 /* Note that the smb header signature field on input contains the
  36         sequence number before this function is called */
  37
  38 extern void mdfour(unsigned char *out, unsigned char *in, int n);
  39 extern void E_md4hash(const unsigned char *passwd, unsigned char *p16);
  40 extern void SMBencrypt(unsigned char *passwd, unsigned char *c8,
  41                        unsigned char *p24);
  42
  43 static int cifs_calculate_signature(const struct smb_hdr * cifs_pdu,
  44                                     const char * key, char * signature)
  45 {
  46         struct  MD5Context context;
  47
  48         if((cifs_pdu == NULL) || (signature == NULL))
  49                 return -EINVAL;
  50
  51         MD5Init(&context);
  52         MD5Update(&context,key,CIFS_SESS_KEY_SIZE+16);
  53         MD5Update(&context,cifs_pdu->Protocol,cifs_pdu->smb_buf_length);
  54         MD5Final(signature,&context);
  55         return 0;
  56 }
  57
  58 int cifs_sign_smb(struct smb_hdr * cifs_pdu, struct TCP_Server_Info * server,
  59         __u32 * pexpected_response_sequence_number)
  60 {
  61         int rc = 0;
  62         char smb_signature[20];
  63
  64         if((cifs_pdu == NULL) || (server == NULL))
  65                 return -EINVAL;
  66
  67         if((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
  68                 return rc;
  69
  70         spin_lock(&GlobalMid_Lock);
  71         cifs_pdu->Signature.Sequence.SequenceNumber = cpu_to_le32(server->sequence_number);
  72         cifs_pdu->Signature.Sequence.Reserved = 0;
  73
  74         *pexpected_response_sequence_number = server->sequence_number++;
  75         server->sequence_number++;
  76         spin_unlock(&GlobalMid_Lock);
  77
  78         rc = cifs_calculate_signature(cifs_pdu, server->mac_signing_key,smb_signature);
  79         if(rc)
  80                 memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
  81         else
  82                 memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
  83
  84         return rc;
  85 }
  86
  87 static int cifs_calc_signature2(const struct kvec * iov, int n_vec,
  88                                 const char * key, char * signature)
  89 {
  90         struct  MD5Context context;
  91         int i;
  92
  93         if((iov == NULL) || (signature == NULL))
  94                 return -EINVAL;
  95
  96         MD5Init(&context);
  97         MD5Update(&context,key,CIFS_SESS_KEY_SIZE+16);
  98         for(i=0;i<n_vec;i++) {
  99                 if(iov[i].iov_base == NULL) {
 100                         cERROR(1,("null iovec entry"));
 101                         return -EIO;
 102                 } else if(iov[i].iov_len == 0)
 103                         break; /* bail out if we are sent nothing to sign */
 104                 /* The first entry includes a length field (which does not get
 105                    signed that occupies the first 4 bytes before the header */
 106                 if(i==0) {
 107                         if (iov[0].iov_len <= 8 ) /* cmd field at offset 9 */
 108                                 break; /* nothing to sign or corrupt header */
 109                         MD5Update(&context,iov[0].iov_base+4, iov[0].iov_len-4);
 110                 } else
 111                         MD5Update(&context,iov[i].iov_base, iov[i].iov_len);
 112         }
 113
 114         MD5Final(signature,&context);
 115
 116         return 0;
 117 }
 118
 119
 120 int cifs_sign_smb2(struct kvec * iov, int n_vec, struct TCP_Server_Info *server,
 121                    __u32 * pexpected_response_sequence_number)
 122 {
 123         int rc = 0;
 124         char smb_signature[20];
 125         struct smb_hdr * cifs_pdu = iov[0].iov_base;
 126
 127         if((cifs_pdu == NULL) || (server == NULL))
 128                 return -EINVAL;
 129
 130         if((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
 131                 return rc;
 132
 133         spin_lock(&GlobalMid_Lock);
 134         cifs_pdu->Signature.Sequence.SequenceNumber =
 135                                 cpu_to_le32(server->sequence_number);
 136         cifs_pdu->Signature.Sequence.Reserved = 0;
 137
 138         *pexpected_response_sequence_number = server->sequence_number++;
 139         server->sequence_number++;
 140         spin_unlock(&GlobalMid_Lock);
 141
 142         rc = cifs_calc_signature2(iov, n_vec, server->mac_signing_key,
 143                                       smb_signature);
 144         if(rc)
 145                 memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
 146         else
 147                 memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
 148
 149         return rc;
 150
 151 }
 152
 153 int cifs_verify_signature(struct smb_hdr * cifs_pdu, const char * mac_key,
 154         __u32 expected_sequence_number)
 155 {
 156         unsigned int rc;
 157         char server_response_sig[8];
 158         char what_we_think_sig_should_be[20];
 159
 160         if((cifs_pdu == NULL) || (mac_key == NULL))
 161                 return -EINVAL;
 162
 163         if (cifs_pdu->Command == SMB_COM_NEGOTIATE)
 164                 return 0;
 165
 166         if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) {
 167                 struct smb_com_lock_req * pSMB = (struct smb_com_lock_req *)cifs_pdu;
 168             if(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE)
 169                         return 0;
 170         }
 171
 172         /* BB what if signatures are supposed to be on for session but server does not
 173                 send one? BB */
 174
 175         /* Do not need to verify session setups with signature "BSRSPYL "  */
 176         if(memcmp(cifs_pdu->Signature.SecuritySignature,"BSRSPYL ",8)==0)
 177                 cFYI(1,("dummy signature received for smb command 0x%x",cifs_pdu->Command));
 178
 179         /* save off the origiginal signature so we can modify the smb and check
 180                 its signature against what the server sent */
 181         memcpy(server_response_sig,cifs_pdu->Signature.SecuritySignature,8);
 182
 183         cifs_pdu->Signature.Sequence.SequenceNumber = cpu_to_le32(expected_sequence_number);
 184         cifs_pdu->Signature.Sequence.Reserved = 0;
 185
 186         rc = cifs_calculate_signature(cifs_pdu, mac_key,
 187                 what_we_think_sig_should_be);
 188
 189         if(rc)
 190                 return rc;
 191
 192
 193 /*      cifs_dump_mem("what we think it should be: ",what_we_think_sig_should_be,16); */
 194
 195         if(memcmp(server_response_sig, what_we_think_sig_should_be, 8))
 196                 return -EACCES;
 197         else
 198                 return 0;
 199
 200 }
 201
 202 /* We fill in key by putting in 40 byte array which was allocated by caller */
 203 int cifs_calculate_mac_key(char * key, const char * rn, const char * password)
 204 {
 205         char temp_key[16];
 206         if ((key == NULL) || (rn == NULL))
 207                 return -EINVAL;
 208
 209         E_md4hash(password, temp_key);
 210         mdfour(key,temp_key,16);
 211         memcpy(key+16,rn, CIFS_SESS_KEY_SIZE);
 212         return 0;
 213 }
 214
 215 int CalcNTLMv2_partial_mac_key(struct cifsSesInfo * ses,
 216                                 const struct nls_table * nls_info)
 217 {
 218         char temp_hash[16];
 219         struct HMACMD5Context ctx;
 220         char * ucase_buf;
 221         __le16 * unicode_buf;
 222         unsigned int i,user_name_len,dom_name_len;
 223
 224         if(ses == NULL)
 225                 return -EINVAL;
 226
 227         E_md4hash(ses->password, temp_hash);
 228
 229         hmac_md5_init_limK_to_64(temp_hash, 16, &ctx);
 230         user_name_len = strlen(ses->userName);
 231         if(user_name_len > MAX_USERNAME_SIZE)
 232                 return -EINVAL;
 233         if(ses->domainName == NULL)
 234                 return -EINVAL; /* BB should we use CIFS_LINUX_DOM */
 235         dom_name_len = strlen(ses->domainName);
 236         if(dom_name_len > MAX_USERNAME_SIZE)
 237                 return -EINVAL;
 238
 239         ucase_buf = kmalloc((MAX_USERNAME_SIZE+1), GFP_KERNEL);
 240         if(ucase_buf == NULL)
 241                 return -ENOMEM;
 242         unicode_buf = kmalloc((MAX_USERNAME_SIZE+1)*4, GFP_KERNEL);
 243         if(unicode_buf == NULL) {
 244                 kfree(ucase_buf);
 245                 return -ENOMEM;
 246         }
 247
 248         for(i=0;i<user_name_len;i++)
 249                 ucase_buf[i] = nls_info->charset2upper[(int)ses->userName[i]];
 250         ucase_buf[i] = 0;
 251         user_name_len = cifs_strtoUCS(unicode_buf, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
 252         unicode_buf[user_name_len] = 0;
 253         user_name_len++;
 254
 255         for(i=0;i<dom_name_len;i++)
 256                 ucase_buf[i] = nls_info->charset2upper[(int)ses->domainName[i]];
 257         ucase_buf[i] = 0;
 258         dom_name_len = cifs_strtoUCS(unicode_buf+user_name_len, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
 259
 260         unicode_buf[user_name_len + dom_name_len] = 0;
 261         hmac_md5_update((const unsigned char *) unicode_buf,
 262                 (user_name_len+dom_name_len)*2,&ctx);
 263
 264         hmac_md5_final(ses->server->mac_signing_key,&ctx);
 265         kfree(ucase_buf);
 266         kfree(unicode_buf);
 267         return 0;
 268 }
 269
 270 #ifdef CONFIG_CIFS_WEAK_PW_HASH
 271 void calc_lanman_hash(struct cifsSesInfo * ses, char * lnm_session_key)
 272 {
 273         int i;
 274         char password_with_pad[CIFS_ENCPWD_SIZE];
 275
 276         if(ses->server == NULL)
 277                 return;
 278
 279         memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
 280         if(ses->password)
 281                 strncpy(password_with_pad, ses->password, CIFS_ENCPWD_SIZE);
 282
 283         if((ses->server->secMode & SECMODE_PW_ENCRYPT) == 0)
 284                 if(extended_security & CIFSSEC_MAY_PLNTXT) {
 285                         memcpy(lnm_session_key, password_with_pad, CIFS_ENCPWD_SIZE);
 286                         return;
 287                 }
 288
 289         /* calculate old style session key */
 290         /* calling toupper is less broken than repeatedly
 291         calling nls_toupper would be since that will never
 292         work for UTF8, but neither handles multibyte code pages
 293         but the only alternative would be converting to UCS-16 (Unicode)
 294         (using a routine something like UniStrupr) then
 295         uppercasing and then converting back from Unicode - which
 296         would only worth doing it if we knew it were utf8. Basically
 297         utf8 and other multibyte codepages each need their own strupper
 298         function since a byte at a time will ont work. */
 299
 300         for(i = 0; i < CIFS_ENCPWD_SIZE; i++) {
 301                 password_with_pad[i] = toupper(password_with_pad[i]);
 302         }
 303
 304         SMBencrypt(password_with_pad, ses->server->cryptKey, lnm_session_key);
 305         /* clear password before we return/free memory */
 306         memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
 307 }
 308 #endif /* CIFS_WEAK_PW_HASH */
 309
 310 static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
 311                             const struct nls_table * nls_cp)
 312 {
 313         int rc = 0;
 314         int len;
 315         char nt_hash[16];
 316         struct HMACMD5Context * pctxt;
 317         wchar_t * user;
 318         wchar_t * domain;
 319
 320         pctxt = kmalloc(sizeof(struct HMACMD5Context), GFP_KERNEL);
 321
 322         if(pctxt == NULL)
 323                 return -ENOMEM;
 324
 325         /* calculate md4 hash of password */
 326         E_md4hash(ses->password, nt_hash);
 327
 328         /* convert Domainname to unicode and uppercase */
 329         hmac_md5_init_limK_to_64(nt_hash, 16, pctxt);
 330
 331         /* convert ses->userName to unicode and uppercase */
 332         len = strlen(ses->userName);
 333         user = kmalloc(2 + (len * 2), GFP_KERNEL);
 334         if(user == NULL)
 335                 goto calc_exit_2;
 336         len = cifs_strtoUCS(user, ses->userName, len, nls_cp);
 337         UniStrupr(user);
 338         hmac_md5_update((char *)user, 2*len, pctxt);
 339
 340         /* convert ses->domainName to unicode and uppercase */
 341         if(ses->domainName) {
 342                 len = strlen(ses->domainName);
 343
 344                 domain = kmalloc(2 + (len * 2), GFP_KERNEL);
 345                 if(domain == NULL)
 346                         goto calc_exit_1;
 347                 len = cifs_strtoUCS(domain, ses->domainName, len, nls_cp);
 348                 UniStrupr(domain);
 349
 350                 hmac_md5_update((char *)domain, 2*len, pctxt);
 351
 352                 kfree(domain);
 353         }
 354 calc_exit_1:
 355         kfree(user);
 356 calc_exit_2:
 357         /* BB FIXME what about bytes 24 through 40 of the signing key?
 358            compare with the NTLM example */
 359         hmac_md5_final(ses->server->mac_signing_key, pctxt);
 360
 361         return rc;
 362 }
 363
 364 void setup_ntlmv2_rsp(struct cifsSesInfo * ses, char * resp_buf,
 365                       const struct nls_table * nls_cp)
 366 {
 367         int rc;
 368         struct ntlmv2_resp * buf = (struct ntlmv2_resp *)resp_buf;
 369
 370         buf->blob_signature = cpu_to_le32(0x00000101);
 371         buf->reserved = 0;
 372         buf->time = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
 373         get_random_bytes(&buf->client_chal, sizeof(buf->client_chal));
 374         buf->reserved2 = 0;
 375         buf->names[0].type = 0;
 376         buf->names[0].length = 0;
 377
 378         /* calculate buf->ntlmv2_hash */
 379         rc = calc_ntlmv2_hash(ses, nls_cp);
 380         if(rc)
 381                 cERROR(1,("could not get v2 hash rc %d",rc));
 382         CalcNTLMv2_response(ses, resp_buf);
 383 }
 384
 385 void CalcNTLMv2_response(const struct cifsSesInfo * ses, char * v2_session_response)
 386 {
 387         struct HMACMD5Context context;
 388         /* rest of v2 struct already generated */
 389         memcpy(v2_session_response + 8, ses->server->cryptKey,8);
 390         hmac_md5_init_limK_to_64(ses->server->mac_signing_key, 16, &context);
 391
 392         hmac_md5_update(v2_session_response+8,
 393                         sizeof(struct ntlmv2_resp) - 8, &context);
 394
 395         hmac_md5_final(v2_session_response,&context);
 396 /*      cifs_dump_mem("v2_sess_rsp: ", v2_session_response, 32); */
 397 }