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 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 struct mac_key *key, char *signature)
  45 {
  46         struct  MD5Context context;
  47
  48         if ((cifs_pdu == NULL) || (signature == NULL) || (key == NULL))
  49                 return -EINVAL;
  50
  51         MD5Init(&context);
  52         MD5Update(&context, (char *)&key->data, key->len);
  53         MD5Update(&context, cifs_pdu->Protocol, cifs_pdu->smb_buf_length);
  54
  55         MD5Final(signature, &context);
  56         return 0;
  57 }
  58
  59 int cifs_sign_smb(struct smb_hdr *cifs_pdu, struct TCP_Server_Info *server,
  60                   __u32 *pexpected_response_sequence_number)
  61 {
  62         int rc = 0;
  63         char smb_signature[20];
  64
  65         if ((cifs_pdu == NULL) || (server == NULL))
  66                 return -EINVAL;
  67
  68         if ((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
  69                 return rc;
  70
  71         spin_lock(&GlobalMid_Lock);
  72         cifs_pdu->Signature.Sequence.SequenceNumber =
  73                 cpu_to_le32(server->sequence_number);
  74         cifs_pdu->Signature.Sequence.Reserved = 0;
  75
  76         *pexpected_response_sequence_number = server->sequence_number++;
  77         server->sequence_number++;
  78         spin_unlock(&GlobalMid_Lock);
  79
  80         rc = cifs_calculate_signature(cifs_pdu, &server->mac_signing_key,
  81                                       smb_signature);
  82         if (rc)
  83                 memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
  84         else
  85                 memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
  86
  87         return rc;
  88 }
  89
  90 static int cifs_calc_signature2(const struct kvec *iov, int n_vec,
  91                                 const struct mac_key *key, char *signature)
  92 {
  93         struct  MD5Context context;
  94         int i;
  95
  96         if ((iov == NULL) || (signature == NULL) || (key == NULL))
  97                 return -EINVAL;
  98
  99         MD5Init(&context);
 100         MD5Update(&context, (char *)&key->data, key->len);
 101         for (i=0;i<n_vec;i++) {
 102                 if (iov[i].iov_base == NULL) {
 103                         cERROR(1 ,("null iovec entry"));
 104                         return -EIO;
 105                 } else if (iov[i].iov_len == 0)
 106                         break; /* bail out if we are sent nothing to sign */
 107                 /* The first entry includes a length field (which does not get
 108                    signed that occupies the first 4 bytes before the header */
 109                 if (i == 0) {
 110                         if (iov[0].iov_len <= 8 ) /* cmd field at offset 9 */
 111                                 break; /* nothing to sign or corrupt header */
 112                         MD5Update(&context,iov[0].iov_base+4, iov[0].iov_len-4);
 113                 } else
 114                         MD5Update(&context, iov[i].iov_base, iov[i].iov_len);
 115         }
 116
 117         MD5Final(signature, &context);
 118
 119         return 0;
 120 }
 121
 122
 123 int cifs_sign_smb2(struct kvec *iov, int n_vec, struct TCP_Server_Info *server,
 124                    __u32 * pexpected_response_sequence_number)
 125 {
 126         int rc = 0;
 127         char smb_signature[20];
 128         struct smb_hdr *cifs_pdu = iov[0].iov_base;
 129
 130         if ((cifs_pdu == NULL) || (server == NULL))
 131                 return -EINVAL;
 132
 133         if ((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
 134                 return rc;
 135
 136         spin_lock(&GlobalMid_Lock);
 137         cifs_pdu->Signature.Sequence.SequenceNumber =
 138                                 cpu_to_le32(server->sequence_number);
 139         cifs_pdu->Signature.Sequence.Reserved = 0;
 140
 141         *pexpected_response_sequence_number = server->sequence_number++;
 142         server->sequence_number++;
 143         spin_unlock(&GlobalMid_Lock);
 144
 145         rc = cifs_calc_signature2(iov, n_vec, &server->mac_signing_key,
 146                                       smb_signature);
 147         if (rc)
 148                 memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
 149         else
 150                 memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
 151
 152         return rc;
 153 }
 154
 155 int cifs_verify_signature(struct smb_hdr *cifs_pdu,
 156                           const struct mac_key *mac_key,
 157                           __u32 expected_sequence_number)
 158 {
 159         unsigned int rc;
 160         char server_response_sig[8];
 161         char what_we_think_sig_should_be[20];
 162
 163         if ((cifs_pdu == NULL) || (mac_key == NULL))
 164                 return -EINVAL;
 165
 166         if (cifs_pdu->Command == SMB_COM_NEGOTIATE)
 167                 return 0;
 168
 169         if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) {
 170                 struct smb_com_lock_req * pSMB =
 171                         (struct smb_com_lock_req *)cifs_pdu;
 172             if (pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE)
 173                         return 0;
 174         }
 175
 176         /* BB what if signatures are supposed to be on for session but server does not
 177                 send one? BB */
 178
 179         /* Do not need to verify session setups with signature "BSRSPYL "  */
 180         if(memcmp(cifs_pdu->Signature.SecuritySignature,"BSRSPYL ",8)==0)
 181                 cFYI(1,("dummy signature received for smb command 0x%x",cifs_pdu->Command));
 182
 183         /* save off the origiginal signature so we can modify the smb and check
 184                 its signature against what the server sent */
 185         memcpy(server_response_sig,cifs_pdu->Signature.SecuritySignature,8);
 186
 187         cifs_pdu->Signature.Sequence.SequenceNumber = cpu_to_le32(expected_sequence_number);
 188         cifs_pdu->Signature.Sequence.Reserved = 0;
 189
 190         rc = cifs_calculate_signature(cifs_pdu, mac_key,
 191                 what_we_think_sig_should_be);
 192
 193         if(rc)
 194                 return rc;
 195
 196
 197 /*      cifs_dump_mem("what we think it should be: ",what_we_think_sig_should_be,16); */
 198
 199         if(memcmp(server_response_sig, what_we_think_sig_should_be, 8))
 200                 return -EACCES;
 201         else
 202                 return 0;
 203
 204 }
 205
 206 /* We fill in key by putting in 40 byte array which was allocated by caller */
 207 int cifs_calculate_mac_key(struct mac_key *key, const char *rn,
 208                            const char *password)
 209 {
 210         char temp_key[16];
 211         if ((key == NULL) || (rn == NULL))
 212                 return -EINVAL;
 213
 214         E_md4hash(password, temp_key);
 215         mdfour(key->data.ntlm, temp_key, 16);
 216         memcpy(key->data.ntlm+16, rn, CIFS_SESS_KEY_SIZE);
 217         key->len = 40;
 218         return 0;
 219 }
 220
 221 int CalcNTLMv2_partial_mac_key(struct cifsSesInfo * ses,
 222                                 const struct nls_table * nls_info)
 223 {
 224         char temp_hash[16];
 225         struct HMACMD5Context ctx;
 226         char * ucase_buf;
 227         __le16 * unicode_buf;
 228         unsigned int i,user_name_len,dom_name_len;
 229
 230         if(ses == NULL)
 231                 return -EINVAL;
 232
 233         E_md4hash(ses->password, temp_hash);
 234
 235         hmac_md5_init_limK_to_64(temp_hash, 16, &ctx);
 236         user_name_len = strlen(ses->userName);
 237         if(user_name_len > MAX_USERNAME_SIZE)
 238                 return -EINVAL;
 239         if(ses->domainName == NULL)
 240                 return -EINVAL; /* BB should we use CIFS_LINUX_DOM */
 241         dom_name_len = strlen(ses->domainName);
 242         if (dom_name_len > MAX_USERNAME_SIZE)
 243                 return -EINVAL;
 244
 245         ucase_buf = kmalloc((MAX_USERNAME_SIZE+1), GFP_KERNEL);
 246         if (ucase_buf == NULL)
 247                 return -ENOMEM;
 248         unicode_buf = kmalloc((MAX_USERNAME_SIZE+1)*4, GFP_KERNEL);
 249         if (unicode_buf == NULL) {
 250                 kfree(ucase_buf);
 251                 return -ENOMEM;
 252         }
 253
 254         for (i = 0;i < user_name_len; i++)
 255                 ucase_buf[i] = nls_info->charset2upper[(int)ses->userName[i]];
 256         ucase_buf[i] = 0;
 257         user_name_len = cifs_strtoUCS(unicode_buf, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
 258         unicode_buf[user_name_len] = 0;
 259         user_name_len++;
 260
 261         for (i = 0; i < dom_name_len; i++)
 262                 ucase_buf[i] = nls_info->charset2upper[(int)ses->domainName[i]];
 263         ucase_buf[i] = 0;
 264         dom_name_len = cifs_strtoUCS(unicode_buf+user_name_len, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
 265
 266         unicode_buf[user_name_len + dom_name_len] = 0;
 267         hmac_md5_update((const unsigned char *) unicode_buf,
 268                 (user_name_len+dom_name_len)*2, &ctx);
 269
 270         hmac_md5_final(ses->server->ntlmv2_hash, &ctx);
 271         kfree(ucase_buf);
 272         kfree(unicode_buf);
 273         return 0;
 274 }
 275
 276 #ifdef CONFIG_CIFS_WEAK_PW_HASH
 277 void calc_lanman_hash(struct cifsSesInfo * ses, char * lnm_session_key)
 278 {
 279         int i;
 280         char password_with_pad[CIFS_ENCPWD_SIZE];
 281
 282         if(ses->server == NULL)
 283                 return;
 284
 285         memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
 286         if(ses->password)
 287                 strncpy(password_with_pad, ses->password, CIFS_ENCPWD_SIZE);
 288
 289         if((ses->server->secMode & SECMODE_PW_ENCRYPT) == 0)
 290                 if(extended_security & CIFSSEC_MAY_PLNTXT) {
 291                         memcpy(lnm_session_key, password_with_pad, CIFS_ENCPWD_SIZE);
 292                         return;
 293                 }
 294
 295         /* calculate old style session key */
 296         /* calling toupper is less broken than repeatedly
 297         calling nls_toupper would be since that will never
 298         work for UTF8, but neither handles multibyte code pages
 299         but the only alternative would be converting to UCS-16 (Unicode)
 300         (using a routine something like UniStrupr) then
 301         uppercasing and then converting back from Unicode - which
 302         would only worth doing it if we knew it were utf8. Basically
 303         utf8 and other multibyte codepages each need their own strupper
 304         function since a byte at a time will ont work. */
 305
 306         for(i = 0; i < CIFS_ENCPWD_SIZE; i++) {
 307                 password_with_pad[i] = toupper(password_with_pad[i]);
 308         }
 309
 310         SMBencrypt(password_with_pad, ses->server->cryptKey, lnm_session_key);
 311         /* clear password before we return/free memory */
 312         memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
 313 }
 314 #endif /* CIFS_WEAK_PW_HASH */
 315
 316 static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
 317                             const struct nls_table * nls_cp)
 318 {
 319         int rc = 0;
 320         int len;
 321         char nt_hash[16];
 322         struct HMACMD5Context * pctxt;
 323         wchar_t * user;
 324         wchar_t * domain;
 325
 326         pctxt = kmalloc(sizeof(struct HMACMD5Context), GFP_KERNEL);
 327
 328         if(pctxt == NULL)
 329                 return -ENOMEM;
 330
 331         /* calculate md4 hash of password */
 332         E_md4hash(ses->password, nt_hash);
 333
 334         /* convert Domainname to unicode and uppercase */
 335         hmac_md5_init_limK_to_64(nt_hash, 16, pctxt);
 336
 337         /* convert ses->userName to unicode and uppercase */
 338         len = strlen(ses->userName);
 339         user = kmalloc(2 + (len * 2), GFP_KERNEL);
 340         if(user == NULL)
 341                 goto calc_exit_2;
 342         len = cifs_strtoUCS(user, ses->userName, len, nls_cp);
 343         UniStrupr(user);
 344         hmac_md5_update((char *)user, 2*len, pctxt);
 345
 346         /* convert ses->domainName to unicode and uppercase */
 347         if(ses->domainName) {
 348                 len = strlen(ses->domainName);
 349
 350                 domain = kmalloc(2 + (len * 2), GFP_KERNEL);
 351                 if(domain == NULL)
 352                         goto calc_exit_1;
 353                 len = cifs_strtoUCS(domain, ses->domainName, len, nls_cp);
 354                 /* the following line was removed since it didn't work well
 355                    with lower cased domain name that passed as an option.
 356                    Maybe converting the domain name earlier makes sense */
 357                 /* UniStrupr(domain); */
 358
 359                 hmac_md5_update((char *)domain, 2*len, pctxt);
 360
 361                 kfree(domain);
 362         }
 363 calc_exit_1:
 364         kfree(user);
 365 calc_exit_2:
 366         /* BB FIXME what about bytes 24 through 40 of the signing key?
 367            compare with the NTLM example */
 368         hmac_md5_final(ses->server->ntlmv2_hash, pctxt);
 369
 370         return rc;
 371 }
 372
 373 void setup_ntlmv2_rsp(struct cifsSesInfo * ses, char * resp_buf,
 374                       const struct nls_table * nls_cp)
 375 {
 376         int rc;
 377         struct ntlmv2_resp * buf = (struct ntlmv2_resp *)resp_buf;
 378         struct HMACMD5Context context;
 379
 380         buf->blob_signature = cpu_to_le32(0x00000101);
 381         buf->reserved = 0;
 382         buf->time = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
 383         get_random_bytes(&buf->client_chal, sizeof(buf->client_chal));
 384         buf->reserved2 = 0;
 385         buf->names[0].type = cpu_to_le16(NTLMSSP_DOMAIN_TYPE);
 386         buf->names[0].length = 0;
 387         buf->names[1].type = 0;
 388         buf->names[1].length = 0;
 389
 390         /* calculate buf->ntlmv2_hash */
 391         rc = calc_ntlmv2_hash(ses, nls_cp);
 392         if(rc)
 393                 cERROR(1,("could not get v2 hash rc %d",rc));
 394         CalcNTLMv2_response(ses, resp_buf);
 395
 396         /* now calculate the MAC key for NTLMv2 */
 397         hmac_md5_init_limK_to_64(ses->server->ntlmv2_hash, 16, &context);
 398         hmac_md5_update(resp_buf, 16, &context);
 399         hmac_md5_final(ses->server->mac_signing_key.data.ntlmv2.key, &context);
 400
 401         memcpy(&ses->server->mac_signing_key.data.ntlmv2.resp, resp_buf,
 402                sizeof(struct ntlmv2_resp));
 403         ses->server->mac_signing_key.len = 16 + sizeof(struct ntlmv2_resp);
 404 }
 405
 406 void CalcNTLMv2_response(const struct cifsSesInfo * ses, char * v2_session_response)
 407 {
 408         struct HMACMD5Context context;
 409         /* rest of v2 struct already generated */
 410         memcpy(v2_session_response + 8, ses->server->cryptKey,8);
 411         hmac_md5_init_limK_to_64(ses->server->ntlmv2_hash, 16, &context);
 412
 413         hmac_md5_update(v2_session_response+8,
 414                         sizeof(struct ntlmv2_resp) - 8, &context);
 415
 416         hmac_md5_final(v2_session_response,&context);
 417 /*      cifs_dump_mem("v2_sess_rsp: ", v2_session_response, 32); */
 418 }