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 <linux/slab.h> 24#include "cifspdu.h" 25#include "cifsglob.h" 26#include "cifs_debug.h" 27#include "md5.h" 28#include "cifs_unicode.h" 29#include "cifsproto.h" 30#include <linux/ctype.h> 31#include <linux/random.h> 32 33/* Calculate and return the CIFS signature based on the mac key and SMB PDU */ 34/* the 16 byte signature must be allocated by the caller */ 35/* Note we only use the 1st eight bytes */ 36/* Note that the smb header signature field on input contains the 37 sequence number before this function is called */ 38 39extern void mdfour(unsigned char *out, unsigned char *in, int n); 40extern void E_md4hash(const unsigned char *passwd, unsigned char *p16); 41extern void SMBencrypt(unsigned char *passwd, const unsigned char *c8, 42 unsigned char *p24); 43 44static int cifs_calculate_signature(const struct smb_hdr *cifs_pdu, 45 const struct mac_key *key, char *signature) 46{ 47 struct MD5Context context; 48 49 if ((cifs_pdu == NULL) || (signature == NULL) || (key == NULL)) 50 return -EINVAL; 51 52 cifs_MD5_init(&context); 53 cifs_MD5_update(&context, (char *)&key->data, key->len); 54 cifs_MD5_update(&context, cifs_pdu->Protocol, cifs_pdu->smb_buf_length); 55 56 cifs_MD5_final(signature, &context); 57 return 0; 58} 59 60int cifs_sign_smb(struct smb_hdr *cifs_pdu, struct TCP_Server_Info *server, 61 __u32 *pexpected_response_sequence_number) 62{ 63 int rc = 0; 64 char smb_signature[20]; 65 66 if ((cifs_pdu == NULL) || (server == NULL)) 67 return -EINVAL; 68 69 if ((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0) 70 return rc; 71 72 spin_lock(&GlobalMid_Lock); 73 cifs_pdu->Signature.Sequence.SequenceNumber = 74 cpu_to_le32(server->sequence_number); 75 cifs_pdu->Signature.Sequence.Reserved = 0; 76 77 *pexpected_response_sequence_number = server->sequence_number++; 78 server->sequence_number++; 79 spin_unlock(&GlobalMid_Lock); 80 81 rc = cifs_calculate_signature(cifs_pdu, &server->mac_signing_key, 82 smb_signature); 83 if (rc) 84 memset(cifs_pdu->Signature.SecuritySignature, 0, 8); 85 else 86 memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8); 87 88 return rc; 89} 90 91static int cifs_calc_signature2(const struct kvec *iov, int n_vec, 92 const struct mac_key *key, char *signature) 93{ 94 struct MD5Context context; 95 int i; 96 97 if ((iov == NULL) || (signature == NULL) || (key == NULL)) 98 return -EINVAL; 99 100 cifs_MD5_init(&context); 101 cifs_MD5_update(&context, (char *)&key->data, key->len); 102 for (i = 0; i < n_vec; i++) { 103 if (iov[i].iov_len == 0) 104 continue; 105 if (iov[i].iov_base == NULL) { 106 cERROR(1, "null iovec entry"); 107 return -EIO; 108 } 109 /* The first entry includes a length field (which does not get 110 signed that occupies the first 4 bytes before the header */ 111 if (i == 0) { 112 if (iov[0].iov_len <= 8) /* cmd field at offset 9 */ 113 break; /* nothing to sign or corrupt header */ 114 cifs_MD5_update(&context, iov[0].iov_base+4, 115 iov[0].iov_len-4); 116 } else 117 cifs_MD5_update(&context, iov[i].iov_base, iov[i].iov_len); 118 } 119 120 cifs_MD5_final(signature, &context); 121 122 return 0; 123} 124 125 126int cifs_sign_smb2(struct kvec *iov, int n_vec, struct TCP_Server_Info *server, 127 __u32 *pexpected_response_sequence_number) 128{ 129 int rc = 0; 130 char smb_signature[20]; 131 struct smb_hdr *cifs_pdu = iov[0].iov_base; 132 133 if ((cifs_pdu == NULL) || (server == NULL)) 134 return -EINVAL; 135 136 if ((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0) 137 return rc; 138 139 spin_lock(&GlobalMid_Lock); 140 cifs_pdu->Signature.Sequence.SequenceNumber = 141 cpu_to_le32(server->sequence_number); 142 cifs_pdu->Signature.Sequence.Reserved = 0; 143 144 *pexpected_response_sequence_number = server->sequence_number++; 145 server->sequence_number++; 146 spin_unlock(&GlobalMid_Lock); 147 148 rc = cifs_calc_signature2(iov, n_vec, &server->mac_signing_key, 149 smb_signature); 150 if (rc) 151 memset(cifs_pdu->Signature.SecuritySignature, 0, 8); 152 else 153 memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8); 154 155 return rc; 156} 157 158int cifs_verify_signature(struct smb_hdr *cifs_pdu, 159 const struct mac_key *mac_key, 160 __u32 expected_sequence_number) 161{ 162 unsigned int rc; 163 char server_response_sig[8]; 164 char what_we_think_sig_should_be[20]; 165 166 if ((cifs_pdu == NULL) || (mac_key == NULL)) 167 return -EINVAL; 168 169 if (cifs_pdu->Command == SMB_COM_NEGOTIATE) 170 return 0; 171 172 if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) { 173 struct smb_com_lock_req *pSMB = 174 (struct smb_com_lock_req *)cifs_pdu; 175 if (pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE) 176 return 0; 177 } 178 179 /* BB what if signatures are supposed to be on for session but 180 server does not send one? BB */ 181 182 /* Do not need to verify session setups with signature "BSRSPYL " */ 183 if (memcmp(cifs_pdu->Signature.SecuritySignature, "BSRSPYL ", 8) == 0) 184 cFYI(1, "dummy signature received for smb command 0x%x", 185 cifs_pdu->Command); 186 187 /* save off the origiginal signature so we can modify the smb and check 188 its signature against what the server sent */ 189 memcpy(server_response_sig, cifs_pdu->Signature.SecuritySignature, 8); 190 191 cifs_pdu->Signature.Sequence.SequenceNumber = 192 cpu_to_le32(expected_sequence_number); 193 cifs_pdu->Signature.Sequence.Reserved = 0; 194 195 rc = cifs_calculate_signature(cifs_pdu, mac_key, 196 what_we_think_sig_should_be); 197 198 if (rc) 199 return rc; 200 201/* cifs_dump_mem("what we think it should be: ", 202 what_we_think_sig_should_be, 16); */ 203 204 if (memcmp(server_response_sig, what_we_think_sig_should_be, 8)) 205 return -EACCES; 206 else 207 return 0; 208 209} 210 211/* We fill in key by putting in 40 byte array which was allocated by caller */ 212int cifs_calculate_mac_key(struct mac_key *key, const char *rn, 213 const char *password) 214{ 215 char temp_key[16]; 216 if ((key == NULL) || (rn == NULL)) 217 return -EINVAL; 218 219 E_md4hash(password, temp_key); 220 mdfour(key->data.ntlm, temp_key, 16); 221 memcpy(key->data.ntlm+16, rn, CIFS_SESS_KEY_SIZE); 222 key->len = 40; 223 return 0; 224} 225 226#ifdef CONFIG_CIFS_WEAK_PW_HASH 227void calc_lanman_hash(const char *password, const char *cryptkey, bool encrypt, 228 char *lnm_session_key) 229{ 230 int i; 231 char password_with_pad[CIFS_ENCPWD_SIZE]; 232 233 memset(password_with_pad, 0, CIFS_ENCPWD_SIZE); 234 if (password) 235 strncpy(password_with_pad, password, CIFS_ENCPWD_SIZE); 236 237 if (!encrypt && global_secflags & CIFSSEC_MAY_PLNTXT) { 238 memset(lnm_session_key, 0, CIFS_SESS_KEY_SIZE); 239 memcpy(lnm_session_key, password_with_pad, 240 CIFS_ENCPWD_SIZE); 241 return; 242 } 243 244 /* calculate old style session key */ 245 /* calling toupper is less broken than repeatedly 246 calling nls_toupper would be since that will never 247 work for UTF8, but neither handles multibyte code pages 248 but the only alternative would be converting to UCS-16 (Unicode) 249 (using a routine something like UniStrupr) then 250 uppercasing and then converting back from Unicode - which 251 would only worth doing it if we knew it were utf8. Basically 252 utf8 and other multibyte codepages each need their own strupper 253 function since a byte at a time will ont work. */ 254 255 for (i = 0; i < CIFS_ENCPWD_SIZE; i++) 256 password_with_pad[i] = toupper(password_with_pad[i]); 257 258 SMBencrypt(password_with_pad, cryptkey, lnm_session_key); 259 260 /* clear password before we return/free memory */ 261 memset(password_with_pad, 0, CIFS_ENCPWD_SIZE); 262} 263#endif /* CIFS_WEAK_PW_HASH */ 264 265static int calc_ntlmv2_hash(struct cifsSesInfo *ses, 266 const struct nls_table *nls_cp) 267{ 268 int rc = 0; 269 int len; 270 char nt_hash[16]; 271 struct HMACMD5Context *pctxt; 272 wchar_t *user; 273 wchar_t *domain; 274 275 pctxt = kmalloc(sizeof(struct HMACMD5Context), GFP_KERNEL); 276 277 if (pctxt == NULL) 278 return -ENOMEM; 279 280 /* calculate md4 hash of password */ 281 E_md4hash(ses->password, nt_hash); 282 283 /* convert Domainname to unicode and uppercase */ 284 hmac_md5_init_limK_to_64(nt_hash, 16, pctxt); 285 286 /* convert ses->userName to unicode and uppercase */ 287 len = strlen(ses->userName); 288 user = kmalloc(2 + (len * 2), GFP_KERNEL); 289 if (user == NULL) 290 goto calc_exit_2; 291 len = cifs_strtoUCS((__le16 *)user, ses->userName, len, nls_cp); 292 UniStrupr(user); 293 hmac_md5_update((char *)user, 2*len, pctxt); 294 295 /* convert ses->domainName to unicode and uppercase */ 296 if (ses->domainName) { 297 len = strlen(ses->domainName); 298 299 domain = kmalloc(2 + (len * 2), GFP_KERNEL); 300 if (domain == NULL) 301 goto calc_exit_1; 302 len = cifs_strtoUCS((__le16 *)domain, ses->domainName, len, 303 nls_cp); 304 /* the following line was removed since it didn't work well 305 with lower cased domain name that passed as an option. 306 Maybe converting the domain name earlier makes sense */ 307 /* UniStrupr(domain); */ 308 309 hmac_md5_update((char *)domain, 2*len, pctxt); 310 311 kfree(domain); 312 } 313calc_exit_1: 314 kfree(user); 315calc_exit_2: 316 hmac_md5_final(ses->server->ntlmv2_hash, pctxt); 317 318 kfree(pctxt); 319 return rc; 320} 321 322void setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf, 323 const struct nls_table *nls_cp) 324{ 325 int rc; 326 struct ntlmv2_resp *buf = (struct ntlmv2_resp *)resp_buf; 327 struct HMACMD5Context context; 328 329 buf->blob_signature = cpu_to_le32(0x00000101); 330 buf->reserved = 0; 331 buf->time = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME)); 332 get_random_bytes(&buf->client_chal, sizeof(buf->client_chal)); 333 buf->reserved2 = 0; 334 buf->names[0].type = cpu_to_le16(NTLMSSP_DOMAIN_TYPE); 335 buf->names[0].length = 0; 336 buf->names[1].type = 0; 337 buf->names[1].length = 0; 338 339 /* calculate buf->ntlmv2_hash */ 340 rc = calc_ntlmv2_hash(ses, nls_cp); 341 if (rc) 342 cERROR(1, "could not get v2 hash rc %d", rc); 343 CalcNTLMv2_response(ses, resp_buf); 344 345 /* now calculate the MAC key for NTLMv2 */ 346 hmac_md5_init_limK_to_64(ses->server->ntlmv2_hash, 16, &context); 347 hmac_md5_update(resp_buf, 16, &context); 348 hmac_md5_final(ses->server->mac_signing_key.data.ntlmv2.key, &context); 349 350 memcpy(&ses->server->mac_signing_key.data.ntlmv2.resp, resp_buf, 351 sizeof(struct ntlmv2_resp)); 352 ses->server->mac_signing_key.len = 16 + sizeof(struct ntlmv2_resp); 353} 354 355void CalcNTLMv2_response(const struct cifsSesInfo *ses, 356 char *v2_session_response) 357{ 358 struct HMACMD5Context context; 359 /* rest of v2 struct already generated */ 360 memcpy(v2_session_response + 8, ses->server->cryptKey, 8); 361 hmac_md5_init_limK_to_64(ses->server->ntlmv2_hash, 16, &context); 362 363 hmac_md5_update(v2_session_response+8, 364 sizeof(struct ntlmv2_resp) - 8, &context); 365 366 hmac_md5_final(v2_session_response, &context); 367/* cifs_dump_mem("v2_sess_rsp: ", v2_session_response, 32); */ 368} 369