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,
 113                                   iov[0].iov_len-4);
 114                 } else
 115                         MD5Update(&context, iov[i].iov_base, iov[i].iov_len);
 116         }
 117
 118         MD5Final(signature, &context);
 119
 120         return 0;
 121 }
 122
 123
 124 int cifs_sign_smb2(struct kvec *iov, int n_vec, struct TCP_Server_Info *server,
 125                    __u32 * pexpected_response_sequence_number)
 126 {
 127         int rc = 0;
 128         char smb_signature[20];
 129         struct smb_hdr *cifs_pdu = iov[0].iov_base;
 130
 131         if ((cifs_pdu == NULL) || (server == NULL))
 132                 return -EINVAL;
 133
 134         if ((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
 135                 return rc;
 136
 137         spin_lock(&GlobalMid_Lock);
 138         cifs_pdu->Signature.Sequence.SequenceNumber =
 139                                 cpu_to_le32(server->sequence_number);
 140         cifs_pdu->Signature.Sequence.Reserved = 0;
 141
 142         *pexpected_response_sequence_number = server->sequence_number++;
 143         server->sequence_number++;
 144         spin_unlock(&GlobalMid_Lock);
 145
 146         rc = cifs_calc_signature2(iov, n_vec, &server->mac_signing_key,
 147                                       smb_signature);
 148         if (rc)
 149                 memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
 150         else
 151                 memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
 152
 153         return rc;
 154 }
 155
 156 int cifs_verify_signature(struct smb_hdr *cifs_pdu,
 157                           const struct mac_key *mac_key,
 158                           __u32 expected_sequence_number)
 159 {
 160         unsigned int rc;
 161         char server_response_sig[8];
 162         char what_we_think_sig_should_be[20];
 163
 164         if ((cifs_pdu == NULL) || (mac_key == NULL))
 165                 return -EINVAL;
 166
 167         if (cifs_pdu->Command == SMB_COM_NEGOTIATE)
 168                 return 0;
 169
 170         if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) {
 171                 struct smb_com_lock_req *pSMB =
 172                         (struct smb_com_lock_req *)cifs_pdu;
 173             if (pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE)
 174                         return 0;
 175         }
 176
 177         /* BB what if signatures are supposed to be on for session but
 178            server does not send one? BB */
 179
 180         /* Do not need to verify session setups with signature "BSRSPYL "  */
 181         if (memcmp(cifs_pdu->Signature.SecuritySignature, "BSRSPYL ", 8) == 0)
 182                 cFYI(1, ("dummy signature received for smb command 0x%x",
 183                         cifs_pdu->Command));
 184
 185         /* save off the origiginal signature so we can modify the smb and check
 186                 its signature against what the server sent */
 187         memcpy(server_response_sig, cifs_pdu->Signature.SecuritySignature, 8);
 188
 189         cifs_pdu->Signature.Sequence.SequenceNumber =
 190                                         cpu_to_le32(expected_sequence_number);
 191         cifs_pdu->Signature.Sequence.Reserved = 0;
 192
 193         rc = cifs_calculate_signature(cifs_pdu, mac_key,
 194                 what_we_think_sig_should_be);
 195
 196         if (rc)
 197                 return rc;
 198
 199 /*      cifs_dump_mem("what we think it should be: ",
 200                       what_we_think_sig_should_be, 16); */
 201
 202         if (memcmp(server_response_sig, what_we_think_sig_should_be, 8))
 203                 return -EACCES;
 204         else
 205                 return 0;
 206
 207 }
 208
 209 /* We fill in key by putting in 40 byte array which was allocated by caller */
 210 int cifs_calculate_mac_key(struct mac_key *key, const char *rn,
 211                            const char *password)
 212 {
 213         char temp_key[16];
 214         if ((key == NULL) || (rn == NULL))
 215                 return -EINVAL;
 216
 217         E_md4hash(password, temp_key);
 218         mdfour(key->data.ntlm, temp_key, 16);
 219         memcpy(key->data.ntlm+16, rn, CIFS_SESS_KEY_SIZE);
 220         key->len = 40;
 221         return 0;
 222 }
 223
 224 int CalcNTLMv2_partial_mac_key(struct cifsSesInfo *ses,
 225                                const struct nls_table *nls_info)
 226 {
 227         char temp_hash[16];
 228         struct HMACMD5Context ctx;
 229         char *ucase_buf;
 230         __le16 *unicode_buf;
 231         unsigned int i, user_name_len, dom_name_len;
 232
 233         if (ses == NULL)
 234                 return -EINVAL;
 235
 236         E_md4hash(ses->password, temp_hash);
 237
 238         hmac_md5_init_limK_to_64(temp_hash, 16, &ctx);
 239         user_name_len = strlen(ses->userName);
 240         if (user_name_len > MAX_USERNAME_SIZE)
 241                 return -EINVAL;
 242         if (ses->domainName == NULL)
 243                 return -EINVAL; /* BB should we use CIFS_LINUX_DOM */
 244         dom_name_len = strlen(ses->domainName);
 245         if (dom_name_len > MAX_USERNAME_SIZE)
 246                 return -EINVAL;
 247
 248         ucase_buf = kmalloc((MAX_USERNAME_SIZE+1), GFP_KERNEL);
 249         if (ucase_buf == NULL)
 250                 return -ENOMEM;
 251         unicode_buf = kmalloc((MAX_USERNAME_SIZE+1)*4, GFP_KERNEL);
 252         if (unicode_buf == NULL) {
 253                 kfree(ucase_buf);
 254                 return -ENOMEM;
 255         }
 256
 257         for (i = 0; i < user_name_len; i++)
 258                 ucase_buf[i] = nls_info->charset2upper[(int)ses->userName[i]];
 259         ucase_buf[i] = 0;
 260         user_name_len = cifs_strtoUCS(unicode_buf, ucase_buf,
 261                                       MAX_USERNAME_SIZE*2, nls_info);
 262         unicode_buf[user_name_len] = 0;
 263         user_name_len++;
 264
 265         for (i = 0; i < dom_name_len; i++)
 266                 ucase_buf[i] = nls_info->charset2upper[(int)ses->domainName[i]];
 267         ucase_buf[i] = 0;
 268         dom_name_len = cifs_strtoUCS(unicode_buf+user_name_len, ucase_buf,
 269                                      MAX_USERNAME_SIZE*2, nls_info);
 270
 271         unicode_buf[user_name_len + dom_name_len] = 0;
 272         hmac_md5_update((const unsigned char *) unicode_buf,
 273                 (user_name_len+dom_name_len)*2, &ctx);
 274
 275         hmac_md5_final(ses->server->ntlmv2_hash, &ctx);
 276         kfree(ucase_buf);
 277         kfree(unicode_buf);
 278         return 0;
 279 }
 280
 281 #ifdef CONFIG_CIFS_WEAK_PW_HASH
 282 void calc_lanman_hash(struct cifsSesInfo *ses, char *lnm_session_key)
 283 {
 284         int i;
 285         char password_with_pad[CIFS_ENCPWD_SIZE];
 286
 287         if (ses->server == NULL)
 288                 return;
 289
 290         memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
 291         if (ses->password)
 292                 strncpy(password_with_pad, ses->password, CIFS_ENCPWD_SIZE);
 293
 294         if ((ses->server->secMode & SECMODE_PW_ENCRYPT) == 0)
 295                 if (extended_security & CIFSSEC_MAY_PLNTXT) {
 296                         memcpy(lnm_session_key, password_with_pad,
 297                                 CIFS_ENCPWD_SIZE);
 298                         return;
 299                 }
 300
 301         /* calculate old style session key */
 302         /* calling toupper is less broken than repeatedly
 303         calling nls_toupper would be since that will never
 304         work for UTF8, but neither handles multibyte code pages
 305         but the only alternative would be converting to UCS-16 (Unicode)
 306         (using a routine something like UniStrupr) then
 307         uppercasing and then converting back from Unicode - which
 308         would only worth doing it if we knew it were utf8. Basically
 309         utf8 and other multibyte codepages each need their own strupper
 310         function since a byte at a time will ont work. */
 311
 312         for (i = 0; i < CIFS_ENCPWD_SIZE; i++) {
 313                 password_with_pad[i] = toupper(password_with_pad[i]);
 314         }
 315
 316         SMBencrypt(password_with_pad, ses->server->cryptKey, lnm_session_key);
 317         /* clear password before we return/free memory */
 318         memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
 319 }
 320 #endif /* CIFS_WEAK_PW_HASH */
 321
 322 static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
 323                             const struct nls_table *nls_cp)
 324 {
 325         int rc = 0;
 326         int len;
 327         char nt_hash[16];
 328         struct HMACMD5Context *pctxt;
 329         wchar_t *user;
 330         wchar_t *domain;
 331
 332         pctxt = kmalloc(sizeof(struct HMACMD5Context), GFP_KERNEL);
 333
 334         if (pctxt == NULL)
 335                 return -ENOMEM;
 336
 337         /* calculate md4 hash of password */
 338         E_md4hash(ses->password, nt_hash);
 339
 340         /* convert Domainname to unicode and uppercase */
 341         hmac_md5_init_limK_to_64(nt_hash, 16, pctxt);
 342
 343         /* convert ses->userName to unicode and uppercase */
 344         len = strlen(ses->userName);
 345         user = kmalloc(2 + (len * 2), GFP_KERNEL);
 346         if (user == NULL)
 347                 goto calc_exit_2;
 348         len = cifs_strtoUCS(user, ses->userName, len, nls_cp);
 349         UniStrupr(user);
 350         hmac_md5_update((char *)user, 2*len, pctxt);
 351
 352         /* convert ses->domainName to unicode and uppercase */
 353         if (ses->domainName) {
 354                 len = strlen(ses->domainName);
 355
 356                 domain = kmalloc(2 + (len * 2), GFP_KERNEL);
 357                 if (domain == NULL)
 358                         goto calc_exit_1;
 359                 len = cifs_strtoUCS(domain, ses->domainName, len, nls_cp);
 360                 /* the following line was removed since it didn't work well
 361                    with lower cased domain name that passed as an option.
 362                    Maybe converting the domain name earlier makes sense */
 363                 /* UniStrupr(domain); */
 364
 365                 hmac_md5_update((char *)domain, 2*len, pctxt);
 366
 367                 kfree(domain);
 368         }
 369 calc_exit_1:
 370         kfree(user);
 371 calc_exit_2:
 372         /* BB FIXME what about bytes 24 through 40 of the signing key?
 373            compare with the NTLM example */
 374         hmac_md5_final(ses->server->ntlmv2_hash, pctxt);
 375
 376         return rc;
 377 }
 378
 379 void setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,
 380                       const struct nls_table *nls_cp)
 381 {
 382         int rc;
 383         struct ntlmv2_resp *buf = (struct ntlmv2_resp *)resp_buf;
 384         struct HMACMD5Context context;
 385
 386         buf->blob_signature = cpu_to_le32(0x00000101);
 387         buf->reserved = 0;
 388         buf->time = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
 389         get_random_bytes(&buf->client_chal, sizeof(buf->client_chal));
 390         buf->reserved2 = 0;
 391         buf->names[0].type = cpu_to_le16(NTLMSSP_DOMAIN_TYPE);
 392         buf->names[0].length = 0;
 393         buf->names[1].type = 0;
 394         buf->names[1].length = 0;
 395
 396         /* calculate buf->ntlmv2_hash */
 397         rc = calc_ntlmv2_hash(ses, nls_cp);
 398         if (rc)
 399                 cERROR(1, ("could not get v2 hash rc %d", rc));
 400         CalcNTLMv2_response(ses, resp_buf);
 401
 402         /* now calculate the MAC key for NTLMv2 */
 403         hmac_md5_init_limK_to_64(ses->server->ntlmv2_hash, 16, &context);
 404         hmac_md5_update(resp_buf, 16, &context);
 405         hmac_md5_final(ses->server->mac_signing_key.data.ntlmv2.key, &context);
 406
 407         memcpy(&ses->server->mac_signing_key.data.ntlmv2.resp, resp_buf,
 408                sizeof(struct ntlmv2_resp));
 409         ses->server->mac_signing_key.len = 16 + sizeof(struct ntlmv2_resp);
 410 }
 411
 412 void CalcNTLMv2_response(const struct cifsSesInfo *ses,
 413                          char *v2_session_response)
 414 {
 415         struct HMACMD5Context context;
 416         /* rest of v2 struct already generated */
 417         memcpy(v2_session_response + 8, ses->server->cryptKey, 8);
 418         hmac_md5_init_limK_to_64(ses->server->ntlmv2_hash, 16, &context);
 419
 420         hmac_md5_update(v2_session_response+8,
 421                         sizeof(struct ntlmv2_resp) - 8, &context);
 422
 423         hmac_md5_final(v2_session_response, &context);
 424 /*      cifs_dump_mem("v2_sess_rsp: ", v2_session_response, 32); */
 425 }