linux/fs/cifs/cifsencrypt.c
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   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
  38extern void mdfour(unsigned char *out, unsigned char *in, int n);
  39extern void E_md4hash(const unsigned char *passwd, unsigned char *p16);
  40extern void SMBencrypt(unsigned char *passwd, unsigned char *c8,
  41                       unsigned char *p24);
  42
  43static 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
  59int 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
  90static 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_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                        MD5Update(&context, iov[0].iov_base+4,
 114                                  iov[0].iov_len-4);
 115                } else
 116                        MD5Update(&context, iov[i].iov_base, iov[i].iov_len);
 117        }
 118
 119        MD5Final(signature, &context);
 120
 121        return 0;
 122}
 123
 124
 125int 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
 157int 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 */
 211int 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
 225int 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
 283void calc_lanman_hash(struct cifsSesInfo *ses, char *lnm_session_key)
 284{
 285        int i;
 286        char password_with_pad[CIFS_ENCPWD_SIZE];
 287
 288        if (ses->server == NULL)
 289                return;
 290
 291        memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
 292        if (ses->password)
 293                strncpy(password_with_pad, ses->password, CIFS_ENCPWD_SIZE);
 294
 295        if ((ses->server->secMode & SECMODE_PW_ENCRYPT) == 0)
 296                if (extended_security & CIFSSEC_MAY_PLNTXT) {
 297                        memset(lnm_session_key, 0, CIFS_SESS_KEY_SIZE);
 298                        memcpy(lnm_session_key, password_with_pad,
 299                                CIFS_ENCPWD_SIZE);
 300                        return;
 301                }
 302
 303        /* calculate old style session key */
 304        /* calling toupper is less broken than repeatedly
 305        calling nls_toupper would be since that will never
 306        work for UTF8, but neither handles multibyte code pages
 307        but the only alternative would be converting to UCS-16 (Unicode)
 308        (using a routine something like UniStrupr) then
 309        uppercasing and then converting back from Unicode - which
 310        would only worth doing it if we knew it were utf8. Basically
 311        utf8 and other multibyte codepages each need their own strupper
 312        function since a byte at a time will ont work. */
 313
 314        for (i = 0; i < CIFS_ENCPWD_SIZE; i++)
 315                password_with_pad[i] = toupper(password_with_pad[i]);
 316
 317        SMBencrypt(password_with_pad, ses->server->cryptKey, lnm_session_key);
 318        /* clear password before we return/free memory */
 319        memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
 320}
 321#endif /* CIFS_WEAK_PW_HASH */
 322
 323static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
 324                            const struct nls_table *nls_cp)
 325{
 326        int rc = 0;
 327        int len;
 328        char nt_hash[16];
 329        struct HMACMD5Context *pctxt;
 330        wchar_t *user;
 331        wchar_t *domain;
 332
 333        pctxt = kmalloc(sizeof(struct HMACMD5Context), GFP_KERNEL);
 334
 335        if (pctxt == NULL)
 336                return -ENOMEM;
 337
 338        /* calculate md4 hash of password */
 339        E_md4hash(ses->password, nt_hash);
 340
 341        /* convert Domainname to unicode and uppercase */
 342        hmac_md5_init_limK_to_64(nt_hash, 16, pctxt);
 343
 344        /* convert ses->userName to unicode and uppercase */
 345        len = strlen(ses->userName);
 346        user = kmalloc(2 + (len * 2), GFP_KERNEL);
 347        if (user == NULL)
 348                goto calc_exit_2;
 349        len = cifs_strtoUCS((__le16 *)user, ses->userName, len, nls_cp);
 350        UniStrupr(user);
 351        hmac_md5_update((char *)user, 2*len, pctxt);
 352
 353        /* convert ses->domainName to unicode and uppercase */
 354        if (ses->domainName) {
 355                len = strlen(ses->domainName);
 356
 357                domain = kmalloc(2 + (len * 2), GFP_KERNEL);
 358                if (domain == NULL)
 359                        goto calc_exit_1;
 360                len = cifs_strtoUCS((__le16 *)domain, ses->domainName, len,
 361                                        nls_cp);
 362                /* the following line was removed since it didn't work well
 363                   with lower cased domain name that passed as an option.
 364                   Maybe converting the domain name earlier makes sense */
 365                /* UniStrupr(domain); */
 366
 367                hmac_md5_update((char *)domain, 2*len, pctxt);
 368
 369                kfree(domain);
 370        }
 371calc_exit_1:
 372        kfree(user);
 373calc_exit_2:
 374        /* BB FIXME what about bytes 24 through 40 of the signing key?
 375           compare with the NTLM example */
 376        hmac_md5_final(ses->server->ntlmv2_hash, pctxt);
 377
 378        return rc;
 379}
 380
 381void setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,
 382                      const struct nls_table *nls_cp)
 383{
 384        int rc;
 385        struct ntlmv2_resp *buf = (struct ntlmv2_resp *)resp_buf;
 386        struct HMACMD5Context context;
 387
 388        buf->blob_signature = cpu_to_le32(0x00000101);
 389        buf->reserved = 0;
 390        buf->time = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
 391        get_random_bytes(&buf->client_chal, sizeof(buf->client_chal));
 392        buf->reserved2 = 0;
 393        buf->names[0].type = cpu_to_le16(NTLMSSP_DOMAIN_TYPE);
 394        buf->names[0].length = 0;
 395        buf->names[1].type = 0;
 396        buf->names[1].length = 0;
 397
 398        /* calculate buf->ntlmv2_hash */
 399        rc = calc_ntlmv2_hash(ses, nls_cp);
 400        if (rc)
 401                cERROR(1, ("could not get v2 hash rc %d", rc));
 402        CalcNTLMv2_response(ses, resp_buf);
 403
 404        /* now calculate the MAC key for NTLMv2 */
 405        hmac_md5_init_limK_to_64(ses->server->ntlmv2_hash, 16, &context);
 406        hmac_md5_update(resp_buf, 16, &context);
 407        hmac_md5_final(ses->server->mac_signing_key.data.ntlmv2.key, &context);
 408
 409        memcpy(&ses->server->mac_signing_key.data.ntlmv2.resp, resp_buf,
 410               sizeof(struct ntlmv2_resp));
 411        ses->server->mac_signing_key.len = 16 + sizeof(struct ntlmv2_resp);
 412}
 413
 414void CalcNTLMv2_response(const struct cifsSesInfo *ses,
 415                         char *v2_session_response)
 416{
 417        struct HMACMD5Context context;
 418        /* rest of v2 struct already generated */
 419        memcpy(v2_session_response + 8, ses->server->cryptKey, 8);
 420        hmac_md5_init_limK_to_64(ses->server->ntlmv2_hash, 16, &context);
 421
 422        hmac_md5_update(v2_session_response+8,
 423                        sizeof(struct ntlmv2_resp) - 8, &context);
 424
 425        hmac_md5_final(v2_session_response, &context);
 426/*      cifs_dump_mem("v2_sess_rsp: ", v2_session_response, 32); */
 427}
 428
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