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 }
426
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