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, const 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         cifs_MD5_init(&context);
  52         cifs_MD5_update(&context, (char *)&key->data, key->len);
  53         cifs_MD5_update(&context, cifs_pdu->Protocol, cifs_pdu->smb_buf_length);
  54
  55         cifs_MD5_final(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         cifs_MD5_init(&context);
 100         cifs_MD5_update(&context, (char *)&key->data, key->len);
 101         for (i = 0; i < n_vec; i++) {
 102                 if (iov[i].iov_len == 0)
 103                         continue;
 104                 if (iov[i].iov_base == NULL) {
 105                         cERROR(1, ("null iovec entry"));
 106                         return -EIO;
 107                 }
 108                 /* The first entry includes a length field (which does not get
 109                    signed that occupies the first 4 bytes before the header */
 110                 if (i == 0) {
 111                         if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
 112                                 break; /* nothing to sign or corrupt header */
 113                         cifs_MD5_update(&context, iov[0].iov_base+4,
 114                                   iov[0].iov_len-4);
 115                 } else
 116                         cifs_MD5_update(&context, iov[i].iov_base, iov[i].iov_len);
 117         }
 118
 119         cifs_MD5_final(signature, &context);
 120
 121         return 0;
 122 }
 123
 124
 125 int cifs_sign_smb2(struct kvec *iov, int n_vec, struct TCP_Server_Info *server,
 126                    __u32 *pexpected_response_sequence_number)
 127 {
 128         int rc = 0;
 129         char smb_signature[20];
 130         struct smb_hdr *cifs_pdu = iov[0].iov_base;
 131
 132         if ((cifs_pdu == NULL) || (server == NULL))
 133                 return -EINVAL;
 134
 135         if ((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
 136                 return rc;
 137
 138         spin_lock(&GlobalMid_Lock);
 139         cifs_pdu->Signature.Sequence.SequenceNumber =
 140                                 cpu_to_le32(server->sequence_number);
 141         cifs_pdu->Signature.Sequence.Reserved = 0;
 142
 143         *pexpected_response_sequence_number = server->sequence_number++;
 144         server->sequence_number++;
 145         spin_unlock(&GlobalMid_Lock);
 146
 147         rc = cifs_calc_signature2(iov, n_vec, &server->mac_signing_key,
 148                                       smb_signature);
 149         if (rc)
 150                 memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
 151         else
 152                 memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
 153
 154         return rc;
 155 }
 156
 157 int cifs_verify_signature(struct smb_hdr *cifs_pdu,
 158                           const struct mac_key *mac_key,
 159                           __u32 expected_sequence_number)
 160 {
 161         unsigned int rc;
 162         char server_response_sig[8];
 163         char what_we_think_sig_should_be[20];
 164
 165         if ((cifs_pdu == NULL) || (mac_key == NULL))
 166                 return -EINVAL;
 167
 168         if (cifs_pdu->Command == SMB_COM_NEGOTIATE)
 169                 return 0;
 170
 171         if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) {
 172                 struct smb_com_lock_req *pSMB =
 173                         (struct smb_com_lock_req *)cifs_pdu;
 174             if (pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE)
 175                         return 0;
 176         }
 177
 178         /* BB what if signatures are supposed to be on for session but
 179            server does not send one? BB */
 180
 181         /* Do not need to verify session setups with signature "BSRSPYL "  */
 182         if (memcmp(cifs_pdu->Signature.SecuritySignature, "BSRSPYL ", 8) == 0)
 183                 cFYI(1, ("dummy signature received for smb command 0x%x",
 184                         cifs_pdu->Command));
 185
 186         /* save off the origiginal signature so we can modify the smb and check
 187                 its signature against what the server sent */
 188         memcpy(server_response_sig, cifs_pdu->Signature.SecuritySignature, 8);
 189
 190         cifs_pdu->Signature.Sequence.SequenceNumber =
 191                                         cpu_to_le32(expected_sequence_number);
 192         cifs_pdu->Signature.Sequence.Reserved = 0;
 193
 194         rc = cifs_calculate_signature(cifs_pdu, mac_key,
 195                 what_we_think_sig_should_be);
 196
 197         if (rc)
 198                 return rc;
 199
 200 /*      cifs_dump_mem("what we think it should be: ",
 201                       what_we_think_sig_should_be, 16); */
 202
 203         if (memcmp(server_response_sig, what_we_think_sig_should_be, 8))
 204                 return -EACCES;
 205         else
 206                 return 0;
 207
 208 }
 209
 210 /* We fill in key by putting in 40 byte array which was allocated by caller */
 211 int cifs_calculate_mac_key(struct mac_key *key, const char *rn,
 212                            const char *password)
 213 {
 214         char temp_key[16];
 215         if ((key == NULL) || (rn == NULL))
 216                 return -EINVAL;
 217
 218         E_md4hash(password, temp_key);
 219         mdfour(key->data.ntlm, temp_key, 16);
 220         memcpy(key->data.ntlm+16, rn, CIFS_SESS_KEY_SIZE);
 221         key->len = 40;
 222         return 0;
 223 }
 224
 225 int CalcNTLMv2_partial_mac_key(struct cifsSesInfo *ses,
 226                                const struct nls_table *nls_info)
 227 {
 228         char temp_hash[16];
 229         struct HMACMD5Context ctx;
 230         char *ucase_buf;
 231         __le16 *unicode_buf;
 232         unsigned int i, user_name_len, dom_name_len;
 233
 234         if (ses == NULL)
 235                 return -EINVAL;
 236
 237         E_md4hash(ses->password, temp_hash);
 238
 239         hmac_md5_init_limK_to_64(temp_hash, 16, &ctx);
 240         user_name_len = strlen(ses->userName);
 241         if (user_name_len > MAX_USERNAME_SIZE)
 242                 return -EINVAL;
 243         if (ses->domainName == NULL)
 244                 return -EINVAL; /* BB should we use CIFS_LINUX_DOM */
 245         dom_name_len = strlen(ses->domainName);
 246         if (dom_name_len > MAX_USERNAME_SIZE)
 247                 return -EINVAL;
 248
 249         ucase_buf = kmalloc((MAX_USERNAME_SIZE+1), GFP_KERNEL);
 250         if (ucase_buf == NULL)
 251                 return -ENOMEM;
 252         unicode_buf = kmalloc((MAX_USERNAME_SIZE+1)*4, GFP_KERNEL);
 253         if (unicode_buf == NULL) {
 254                 kfree(ucase_buf);
 255                 return -ENOMEM;
 256         }
 257
 258         for (i = 0; i < user_name_len; i++)
 259                 ucase_buf[i] = nls_info->charset2upper[(int)ses->userName[i]];
 260         ucase_buf[i] = 0;
 261         user_name_len = cifs_strtoUCS(unicode_buf, ucase_buf,
 262                                       MAX_USERNAME_SIZE*2, nls_info);
 263         unicode_buf[user_name_len] = 0;
 264         user_name_len++;
 265
 266         for (i = 0; i < dom_name_len; i++)
 267                 ucase_buf[i] = nls_info->charset2upper[(int)ses->domainName[i]];
 268         ucase_buf[i] = 0;
 269         dom_name_len = cifs_strtoUCS(unicode_buf+user_name_len, ucase_buf,
 270                                      MAX_USERNAME_SIZE*2, nls_info);
 271
 272         unicode_buf[user_name_len + dom_name_len] = 0;
 273         hmac_md5_update((const unsigned char *) unicode_buf,
 274                 (user_name_len+dom_name_len)*2, &ctx);
 275
 276         hmac_md5_final(ses->server->ntlmv2_hash, &ctx);
 277         kfree(ucase_buf);
 278         kfree(unicode_buf);
 279         return 0;
 280 }
 281
 282 #ifdef CONFIG_CIFS_WEAK_PW_HASH
 283 void calc_lanman_hash(const char *password, const char *cryptkey, bool encrypt,
 284                         char *lnm_session_key)
 285 {
 286         int i;
 287         char password_with_pad[CIFS_ENCPWD_SIZE];
 288
 289         memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
 290         if (password)
 291                 strncpy(password_with_pad, password, CIFS_ENCPWD_SIZE);
 292
 293         if (!encrypt && extended_security & CIFSSEC_MAY_PLNTXT) {
 294                 memset(lnm_session_key, 0, CIFS_SESS_KEY_SIZE);
 295                 memcpy(lnm_session_key, password_with_pad,
 296                         CIFS_ENCPWD_SIZE);
 297                 return;
 298         }
 299
 300         /* calculate old style session key */
 301         /* calling toupper is less broken than repeatedly
 302         calling nls_toupper would be since that will never
 303         work for UTF8, but neither handles multibyte code pages
 304         but the only alternative would be converting to UCS-16 (Unicode)
 305         (using a routine something like UniStrupr) then
 306         uppercasing and then converting back from Unicode - which
 307         would only worth doing it if we knew it were utf8. Basically
 308         utf8 and other multibyte codepages each need their own strupper
 309         function since a byte at a time will ont work. */
 310
 311         for (i = 0; i < CIFS_ENCPWD_SIZE; i++)
 312                 password_with_pad[i] = toupper(password_with_pad[i]);
 313
 314         SMBencrypt(password_with_pad, cryptkey, lnm_session_key);
 315
 316         /* clear password before we return/free memory */
 317         memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
 318 }
 319 #endif /* CIFS_WEAK_PW_HASH */
 320
 321 static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
 322                             const struct nls_table *nls_cp)
 323 {
 324         int rc = 0;
 325         int len;
 326         char nt_hash[16];
 327         struct HMACMD5Context *pctxt;
 328         wchar_t *user;
 329         wchar_t *domain;
 330
 331         pctxt = kmalloc(sizeof(struct HMACMD5Context), GFP_KERNEL);
 332
 333         if (pctxt == NULL)
 334                 return -ENOMEM;
 335
 336         /* calculate md4 hash of password */
 337         E_md4hash(ses->password, nt_hash);
 338
 339         /* convert Domainname to unicode and uppercase */
 340         hmac_md5_init_limK_to_64(nt_hash, 16, pctxt);
 341
 342         /* convert ses->userName to unicode and uppercase */
 343         len = strlen(ses->userName);
 344         user = kmalloc(2 + (len * 2), GFP_KERNEL);
 345         if (user == NULL)
 346                 goto calc_exit_2;
 347         len = cifs_strtoUCS((__le16 *)user, ses->userName, len, nls_cp);
 348         UniStrupr(user);
 349         hmac_md5_update((char *)user, 2*len, pctxt);
 350
 351         /* convert ses->domainName to unicode and uppercase */
 352         if (ses->domainName) {
 353                 len = strlen(ses->domainName);
 354
 355                 domain = kmalloc(2 + (len * 2), GFP_KERNEL);
 356                 if (domain == NULL)
 357                         goto calc_exit_1;
 358                 len = cifs_strtoUCS((__le16 *)domain, ses->domainName, len,
 359                                         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 }