[CIFS] Support for setting up SMB sessions to legacy lanman servers
[linux-2.6.git] / 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
30 /* Calculate and return the CIFS signature based on the mac key and the smb pdu */
31 /* the 16 byte signature must be allocated by the caller  */
32 /* Note we only use the 1st eight bytes */
33 /* Note that the smb header signature field on input contains the  
34         sequence number before this function is called */
35
36 extern void mdfour(unsigned char *out, unsigned char *in, int n);
37 extern void E_md4hash(const unsigned char *passwd, unsigned char *p16);
38         
39 static int cifs_calculate_signature(const struct smb_hdr * cifs_pdu, 
40                                     const char * key, char * signature)
41 {
42         struct  MD5Context context;
43
44         if((cifs_pdu == NULL) || (signature == NULL))
45                 return -EINVAL;
46
47         MD5Init(&context);
48         MD5Update(&context,key,CIFS_SESSION_KEY_SIZE+16);
49         MD5Update(&context,cifs_pdu->Protocol,cifs_pdu->smb_buf_length);
50         MD5Final(signature,&context);
51         return 0;
52 }
53
54 int cifs_sign_smb(struct smb_hdr * cifs_pdu, struct TCP_Server_Info * server,
55         __u32 * pexpected_response_sequence_number)
56 {
57         int rc = 0;
58         char smb_signature[20];
59
60         if((cifs_pdu == NULL) || (server == NULL))
61                 return -EINVAL;
62
63         if((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0) 
64                 return rc;
65
66         spin_lock(&GlobalMid_Lock);
67         cifs_pdu->Signature.Sequence.SequenceNumber = cpu_to_le32(server->sequence_number);
68         cifs_pdu->Signature.Sequence.Reserved = 0;
69         
70         *pexpected_response_sequence_number = server->sequence_number++;
71         server->sequence_number++;
72         spin_unlock(&GlobalMid_Lock);
73
74         rc = cifs_calculate_signature(cifs_pdu, server->mac_signing_key,smb_signature);
75         if(rc)
76                 memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
77         else
78                 memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
79
80         return rc;
81 }
82
83 static int cifs_calc_signature2(const struct kvec * iov, int n_vec,
84                                 const char * key, char * signature)
85 {
86         struct  MD5Context context;
87         int i;
88
89         if((iov == NULL) || (signature == NULL))
90                 return -EINVAL;
91
92         MD5Init(&context);
93         MD5Update(&context,key,CIFS_SESSION_KEY_SIZE+16);
94         for(i=0;i<n_vec;i++) {
95                 if(iov[i].iov_base == NULL) {
96                         cERROR(1,("null iovec entry"));
97                         return -EIO;
98                 } else if(iov[i].iov_len == 0)
99                         break; /* bail out if we are sent nothing to sign */
100                 /* The first entry includes a length field (which does not get 
101                    signed that occupies the first 4 bytes before the header */
102                 if(i==0) {
103                         if (iov[0].iov_len <= 8 ) /* cmd field at offset 9 */
104                                 break; /* nothing to sign or corrupt header */
105                         MD5Update(&context,iov[0].iov_base+4, iov[0].iov_len-4);
106                 } else
107                         MD5Update(&context,iov[i].iov_base, iov[i].iov_len);
108         }
109
110         MD5Final(signature,&context);
111
112         return 0;
113 }
114
115
116 int cifs_sign_smb2(struct kvec * iov, int n_vec, struct TCP_Server_Info *server,
117                    __u32 * pexpected_response_sequence_number)
118 {
119         int rc = 0;
120         char smb_signature[20];
121         struct smb_hdr * cifs_pdu = iov[0].iov_base;
122
123         if((cifs_pdu == NULL) || (server == NULL))
124                 return -EINVAL;
125
126         if((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
127                 return rc;
128
129         spin_lock(&GlobalMid_Lock);
130         cifs_pdu->Signature.Sequence.SequenceNumber = 
131                                 cpu_to_le32(server->sequence_number);
132         cifs_pdu->Signature.Sequence.Reserved = 0;
133
134         *pexpected_response_sequence_number = server->sequence_number++;
135         server->sequence_number++;
136         spin_unlock(&GlobalMid_Lock);
137
138         rc = cifs_calc_signature2(iov, n_vec, server->mac_signing_key,
139                                       smb_signature);
140         if(rc)
141                 memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
142         else
143                 memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
144
145         return rc;
146
147 }
148
149 int cifs_verify_signature(struct smb_hdr * cifs_pdu, const char * mac_key,
150         __u32 expected_sequence_number)
151 {
152         unsigned int rc;
153         char server_response_sig[8];
154         char what_we_think_sig_should_be[20];
155
156         if((cifs_pdu == NULL) || (mac_key == NULL))
157                 return -EINVAL;
158
159         if (cifs_pdu->Command == SMB_COM_NEGOTIATE)
160                 return 0;
161
162         if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) {
163                 struct smb_com_lock_req * pSMB = (struct smb_com_lock_req *)cifs_pdu;
164             if(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE)
165                         return 0;
166         }
167
168         /* BB what if signatures are supposed to be on for session but server does not
169                 send one? BB */
170         
171         /* Do not need to verify session setups with signature "BSRSPYL "  */
172         if(memcmp(cifs_pdu->Signature.SecuritySignature,"BSRSPYL ",8)==0)
173                 cFYI(1,("dummy signature received for smb command 0x%x",cifs_pdu->Command));
174
175         /* save off the origiginal signature so we can modify the smb and check
176                 its signature against what the server sent */
177         memcpy(server_response_sig,cifs_pdu->Signature.SecuritySignature,8);
178
179         cifs_pdu->Signature.Sequence.SequenceNumber = cpu_to_le32(expected_sequence_number);
180         cifs_pdu->Signature.Sequence.Reserved = 0;
181
182         rc = cifs_calculate_signature(cifs_pdu, mac_key,
183                 what_we_think_sig_should_be);
184
185         if(rc)
186                 return rc;
187
188         
189 /*      cifs_dump_mem("what we think it should be: ",what_we_think_sig_should_be,16); */
190
191         if(memcmp(server_response_sig, what_we_think_sig_should_be, 8))
192                 return -EACCES;
193         else
194                 return 0;
195
196 }
197
198 /* We fill in key by putting in 40 byte array which was allocated by caller */
199 int cifs_calculate_mac_key(char * key, const char * rn, const char * password)
200 {
201         char temp_key[16];
202         if ((key == NULL) || (rn == NULL))
203                 return -EINVAL;
204
205         E_md4hash(password, temp_key);
206         mdfour(key,temp_key,16);
207         memcpy(key+16,rn, CIFS_SESSION_KEY_SIZE);
208         return 0;
209 }
210
211 int CalcNTLMv2_partial_mac_key(struct cifsSesInfo * ses, struct nls_table * nls_info)
212 {
213         char temp_hash[16];
214         struct HMACMD5Context ctx;
215         char * ucase_buf;
216         __le16 * unicode_buf;
217         unsigned int i,user_name_len,dom_name_len;
218
219         if(ses == NULL)
220                 return -EINVAL;
221
222         E_md4hash(ses->password, temp_hash);
223
224         hmac_md5_init_limK_to_64(temp_hash, 16, &ctx);
225         user_name_len = strlen(ses->userName);
226         if(user_name_len > MAX_USERNAME_SIZE)
227                 return -EINVAL;
228         if(ses->domainName == NULL)
229                 return -EINVAL; /* BB should we use CIFS_LINUX_DOM */
230         dom_name_len = strlen(ses->domainName);
231         if(dom_name_len > MAX_USERNAME_SIZE)
232                 return -EINVAL;
233   
234         ucase_buf = kmalloc((MAX_USERNAME_SIZE+1), GFP_KERNEL);
235         if(ucase_buf == NULL)
236                 return -ENOMEM;
237         unicode_buf = kmalloc((MAX_USERNAME_SIZE+1)*4, GFP_KERNEL);
238         if(unicode_buf == NULL) {
239                 kfree(ucase_buf);
240                 return -ENOMEM;
241         }
242    
243         for(i=0;i<user_name_len;i++)
244                 ucase_buf[i] = nls_info->charset2upper[(int)ses->userName[i]];
245         ucase_buf[i] = 0;
246         user_name_len = cifs_strtoUCS(unicode_buf, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
247         unicode_buf[user_name_len] = 0;
248         user_name_len++;
249
250         for(i=0;i<dom_name_len;i++)
251                 ucase_buf[i] = nls_info->charset2upper[(int)ses->domainName[i]];
252         ucase_buf[i] = 0;
253         dom_name_len = cifs_strtoUCS(unicode_buf+user_name_len, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
254
255         unicode_buf[user_name_len + dom_name_len] = 0;
256         hmac_md5_update((const unsigned char *) unicode_buf,
257                 (user_name_len+dom_name_len)*2,&ctx);
258
259         hmac_md5_final(ses->server->mac_signing_key,&ctx);
260         kfree(ucase_buf);
261         kfree(unicode_buf);
262         return 0;
263 }
264 void CalcNTLMv2_response(const struct cifsSesInfo * ses,char * v2_session_response)
265 {
266         struct HMACMD5Context context;
267         memcpy(v2_session_response + 8, ses->server->cryptKey,8);
268         /* gen_blob(v2_session_response + 16); */
269         hmac_md5_init_limK_to_64(ses->server->mac_signing_key, 16, &context);
270
271         hmac_md5_update(ses->server->cryptKey,8,&context);
272 /*      hmac_md5_update(v2_session_response+16)client thing,8,&context); */ /* BB fix */
273
274         hmac_md5_final(v2_session_response,&context);
275         cifs_dump_mem("v2_sess_rsp: ", v2_session_response, 32); /* BB removeme BB */
276 }