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1 /*** WARNING - THIS CODE HAS NOT BEEN FINISHED! ***/
2 /*** The original PPPD code is written in a way to require either the UNIX DES
3      encryption functions encrypt(3) and setkey(3) or the DES library libdes.
4      Since both is not included in lwIP, MSCHAP currently does not work! */
5 /*****************************************************************************
6 * chpms.c - Network MicroSoft Challenge Handshake Authentication Protocol program file.
7 *
8 * Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
9 * Copyright (c) 1997 by Global Election Systems Inc.  All rights reserved.
10 *
11 * The authors hereby grant permission to use, copy, modify, distribute,
12 * and license this software and its documentation for any purpose, provided
13 * that existing copyright notices are retained in all copies and that this
14 * notice and the following disclaimer are included verbatim in any
15 * distributions. No written agreement, license, or royalty fee is required
16 * for any of the authorized uses.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 ******************************************************************************
30 * REVISION HISTORY
31 *
32 * 03-01-01 Marc Boucher <marc@mbsi.ca>
33 *   Ported to lwIP.
34 * 97-12-08 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
35 *   Original based on BSD chap_ms.c.
36 *****************************************************************************/
37 /*
38  * chap_ms.c - Microsoft MS-CHAP compatible implementation.
39  *
40  * Copyright (c) 1995 Eric Rosenquist, Strata Software Limited.
41  * http://www.strataware.com/
42  *
43  * All rights reserved.
44  *
45  * Redistribution and use in source and binary forms are permitted
46  * provided that the above copyright notice and this paragraph are
47  * duplicated in all such forms and that any documentation,
48  * advertising materials, and other materials related to such
49  * distribution and use acknowledge that the software was developed
50  * by Eric Rosenquist.  The name of the author may not be used to
51  * endorse or promote products derived from this software without
52  * specific prior written permission.
53  *
54  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
55  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
56  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
57  */
58 
59 /*
60  * Modifications by Lauri Pesonen / lpesonen@clinet.fi, april 1997
61  *
62  *   Implemented LANManager type password response to MS-CHAP challenges.
63  *   Now pppd provides both NT style and LANMan style blocks, and the
64  *   prefered is set by option "ms-lanman". Default is to use NT.
65  *   The hash text (StdText) was taken from Win95 RASAPI32.DLL.
66  *
67  *   You should also use DOMAIN\\USERNAME as described in README.MSCHAP80
68  */
69 
70 #define USE_CRYPT
71 
72 #include "lwip/opt.h"
73 
74 #if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
75 
76 #if MSCHAP_SUPPORT /* don't build if not configured for use in lwipopts.h */
77 
78 #include "ppp.h"
79 #include "pppdebug.h"
80 
81 #include "md4.h"
82 #ifndef USE_CRYPT
83 #include "des.h"
84 #endif
85 #include "chap.h"
86 #include "chpms.h"
87 
88 #include <string.h>
89 
90 
91 /*************************/
92 /*** LOCAL DEFINITIONS ***/
93 /*************************/
94 
95 
96 /************************/
97 /*** LOCAL DATA TYPES ***/
98 /************************/
99 typedef struct {
100     u_char LANManResp[24];
101     u_char NTResp[24];
102     u_char UseNT; /* If 1, ignore the LANMan response field */
103 } MS_ChapResponse;
104 /* We use MS_CHAP_RESPONSE_LEN, rather than sizeof(MS_ChapResponse),
105    in case this struct gets padded. */
106 
107 
108 
109 /***********************************/
110 /*** LOCAL FUNCTION DECLARATIONS ***/
111 /***********************************/
112 
113 /* XXX Don't know what to do with these. */
114 extern void setkey(const char *);
115 extern void encrypt(char *, int);
116 
117 static void DesEncrypt (u_char *, u_char *, u_char *);
118 static void MakeKey (u_char *, u_char *);
119 
120 #ifdef USE_CRYPT
121 static void Expand (u_char *, u_char *);
122 static void Collapse (u_char *, u_char *);
123 #endif
124 
125 static void ChallengeResponse(
126   u_char *challenge, /* IN   8 octets */
127   u_char *pwHash,    /* IN  16 octets */
128   u_char *response   /* OUT 24 octets */
129 );
130 static void ChapMS_NT(
131   char *rchallenge,
132   int rchallenge_len,
133   char *secret,
134   int secret_len,
135   MS_ChapResponse *response
136 );
137 static u_char Get7Bits(
138   u_char *input,
139   int startBit
140 );
141 
142 static void
ChallengeResponse(u_char * challenge,u_char * pwHash,u_char * response)143 ChallengeResponse( u_char *challenge, /* IN   8 octets */
144                    u_char *pwHash,    /* IN  16 octets */
145                    u_char *response   /* OUT 24 octets */)
146 {
147   u_char    ZPasswordHash[21];
148 
149   BZERO(ZPasswordHash, sizeof(ZPasswordHash));
150   BCOPY(pwHash, ZPasswordHash, 16);
151 
152 #if 0
153   log_packet(ZPasswordHash, sizeof(ZPasswordHash), "ChallengeResponse - ZPasswordHash", LOG_DEBUG);
154 #endif
155 
156   DesEncrypt(challenge, ZPasswordHash +  0, response + 0);
157   DesEncrypt(challenge, ZPasswordHash +  7, response + 8);
158   DesEncrypt(challenge, ZPasswordHash + 14, response + 16);
159 
160 #if 0
161   log_packet(response, 24, "ChallengeResponse - response", LOG_DEBUG);
162 #endif
163 }
164 
165 
166 #ifdef USE_CRYPT
167 static void
DesEncrypt(u_char * clear,u_char * key,u_char * cipher)168 DesEncrypt( u_char *clear, /* IN  8 octets */
169             u_char *key,   /* IN  7 octets */
170             u_char *cipher /* OUT 8 octets */)
171 {
172   u_char des_key[8];
173   u_char crypt_key[66];
174   u_char des_input[66];
175 
176   MakeKey(key, des_key);
177 
178   Expand(des_key, crypt_key);
179   setkey((char*)crypt_key);
180 
181 #if 0
182   CHAPDEBUG(LOG_INFO, ("DesEncrypt: 8 octet input : %02X%02X%02X%02X%02X%02X%02X%02X\n",
183              clear[0], clear[1], clear[2], clear[3], clear[4], clear[5], clear[6], clear[7]));
184 #endif
185 
186   Expand(clear, des_input);
187   encrypt((char*)des_input, 0);
188   Collapse(des_input, cipher);
189 
190 #if 0
191   CHAPDEBUG(LOG_INFO, ("DesEncrypt: 8 octet output: %02X%02X%02X%02X%02X%02X%02X%02X\n",
192              cipher[0], cipher[1], cipher[2], cipher[3], cipher[4], cipher[5], cipher[6], cipher[7]));
193 #endif
194 }
195 
196 #else /* USE_CRYPT */
197 
198 static void
DesEncrypt(u_char * clear,u_char * key,u_char * cipher)199 DesEncrypt( u_char *clear, /* IN  8 octets */
200             u_char *key,   /* IN  7 octets */
201             u_char *cipher /* OUT 8 octets */)
202 {
203   des_cblock    des_key;
204   des_key_schedule  key_schedule;
205 
206   MakeKey(key, des_key);
207 
208   des_set_key(&des_key, key_schedule);
209 
210 #if 0
211   CHAPDEBUG(LOG_INFO, ("DesEncrypt: 8 octet input : %02X%02X%02X%02X%02X%02X%02X%02X\n",
212              clear[0], clear[1], clear[2], clear[3], clear[4], clear[5], clear[6], clear[7]));
213 #endif
214 
215   des_ecb_encrypt((des_cblock *)clear, (des_cblock *)cipher, key_schedule, 1);
216 
217 #if 0
218   CHAPDEBUG(LOG_INFO, ("DesEncrypt: 8 octet output: %02X%02X%02X%02X%02X%02X%02X%02X\n",
219              cipher[0], cipher[1], cipher[2], cipher[3], cipher[4], cipher[5], cipher[6], cipher[7]));
220 #endif
221 }
222 
223 #endif /* USE_CRYPT */
224 
225 
226 static u_char
Get7Bits(u_char * input,int startBit)227 Get7Bits( u_char *input, int startBit)
228 {
229   register unsigned int  word;
230 
231   word  = (unsigned)input[startBit / 8] << 8;
232   word |= (unsigned)input[startBit / 8 + 1];
233 
234   word >>= 15 - (startBit % 8 + 7);
235 
236   return word & 0xFE;
237 }
238 
239 #ifdef USE_CRYPT
240 
241 /* in == 8-byte string (expanded version of the 56-bit key)
242  * out == 64-byte string where each byte is either 1 or 0
243  * Note that the low-order "bit" is always ignored by by setkey()
244  */
245 static void
Expand(u_char * in,u_char * out)246 Expand(u_char *in, u_char *out)
247 {
248   int j, c;
249   int i;
250 
251   for(i = 0; i < 64; in++){
252     c = *in;
253     for(j = 7; j >= 0; j--) {
254       *out++ = (c >> j) & 01;
255     }
256     i += 8;
257   }
258 }
259 
260 /* The inverse of Expand
261  */
262 static void
Collapse(u_char * in,u_char * out)263 Collapse(u_char *in, u_char *out)
264 {
265   int j;
266   int i;
267   unsigned int c;
268 
269   for (i = 0; i < 64; i += 8, out++) {
270     c = 0;
271     for (j = 7; j >= 0; j--, in++) {
272       c |= *in << j;
273     }
274     *out = c & 0xff;
275   }
276 }
277 #endif
278 
279 static void
MakeKey(u_char * key,u_char * des_key)280 MakeKey( u_char *key,    /* IN  56 bit DES key missing parity bits */
281          u_char *des_key /* OUT 64 bit DES key with parity bits added */)
282 {
283   des_key[0] = Get7Bits(key,  0);
284   des_key[1] = Get7Bits(key,  7);
285   des_key[2] = Get7Bits(key, 14);
286   des_key[3] = Get7Bits(key, 21);
287   des_key[4] = Get7Bits(key, 28);
288   des_key[5] = Get7Bits(key, 35);
289   des_key[6] = Get7Bits(key, 42);
290   des_key[7] = Get7Bits(key, 49);
291 
292 #ifndef USE_CRYPT
293   des_set_odd_parity((des_cblock *)des_key);
294 #endif
295 
296 #if 0
297   CHAPDEBUG(LOG_INFO, ("MakeKey: 56-bit input : %02X%02X%02X%02X%02X%02X%02X\n",
298              key[0], key[1], key[2], key[3], key[4], key[5], key[6]));
299   CHAPDEBUG(LOG_INFO, ("MakeKey: 64-bit output: %02X%02X%02X%02X%02X%02X%02X%02X\n",
300              des_key[0], des_key[1], des_key[2], des_key[3], des_key[4], des_key[5], des_key[6], des_key[7]));
301 #endif
302 }
303 
304 static void
ChapMS_NT(char * rchallenge,int rchallenge_len,char * secret,int secret_len,MS_ChapResponse * response)305 ChapMS_NT( char *rchallenge,
306            int rchallenge_len,
307            char *secret,
308            int secret_len,
309            MS_ChapResponse *response)
310 {
311   int      i;
312   MDstruct  md4Context;
313   u_char    unicodePassword[MAX_NT_PASSWORD * 2];
314   static int  low_byte_first = -1;
315 
316   LWIP_UNUSED_ARG(rchallenge_len);
317 
318   /* Initialize the Unicode version of the secret (== password). */
319   /* This implicitly supports 8-bit ISO8859/1 characters. */
320   BZERO(unicodePassword, sizeof(unicodePassword));
321   for (i = 0; i < secret_len; i++) {
322     unicodePassword[i * 2] = (u_char)secret[i];
323   }
324   MDbegin(&md4Context);
325   MDupdate(&md4Context, unicodePassword, secret_len * 2 * 8);  /* Unicode is 2 bytes/char, *8 for bit count */
326 
327   if (low_byte_first == -1) {
328     low_byte_first = (PP_HTONS((unsigned short int)1) != 1);
329   }
330   if (low_byte_first == 0) {
331     /* @todo: arg type - u_long* or u_int* ? */
332     MDreverse((unsigned int*)&md4Context);  /*  sfb 961105 */
333   }
334 
335   MDupdate(&md4Context, NULL, 0);  /* Tell MD4 we're done */
336 
337   ChallengeResponse((u_char*)rchallenge, (u_char*)md4Context.buffer, response->NTResp);
338 }
339 
340 #ifdef MSLANMAN
341 static u_char *StdText = (u_char *)"KGS!@#$%"; /* key from rasapi32.dll */
342 
343 static void
ChapMS_LANMan(char * rchallenge,int rchallenge_len,char * secret,int secret_len,MS_ChapResponse * response)344 ChapMS_LANMan( char *rchallenge,
345                int rchallenge_len,
346                char *secret,
347                int secret_len,
348                MS_ChapResponse  *response)
349 {
350   int      i;
351   u_char    UcasePassword[MAX_NT_PASSWORD]; /* max is actually 14 */
352   u_char    PasswordHash[16];
353 
354   /* LANMan password is case insensitive */
355   BZERO(UcasePassword, sizeof(UcasePassword));
356   for (i = 0; i < secret_len; i++) {
357     UcasePassword[i] = (u_char)toupper(secret[i]);
358   }
359   DesEncrypt( StdText, UcasePassword + 0, PasswordHash + 0 );
360   DesEncrypt( StdText, UcasePassword + 7, PasswordHash + 8 );
361   ChallengeResponse(rchallenge, PasswordHash, response->LANManResp);
362 }
363 #endif
364 
365 void
ChapMS(chap_state * cstate,char * rchallenge,int rchallenge_len,char * secret,int secret_len)366 ChapMS( chap_state *cstate, char *rchallenge, int rchallenge_len, char *secret, int secret_len)
367 {
368   MS_ChapResponse response;
369 #ifdef MSLANMAN
370   extern int ms_lanman;
371 #endif
372 
373 #if 0
374   CHAPDEBUG(LOG_INFO, ("ChapMS: secret is '%.*s'\n", secret_len, secret));
375 #endif
376   BZERO(&response, sizeof(response));
377 
378   /* Calculate both always */
379   ChapMS_NT(rchallenge, rchallenge_len, secret, secret_len, &response);
380 
381 #ifdef MSLANMAN
382   ChapMS_LANMan(rchallenge, rchallenge_len, secret, secret_len, &response);
383 
384   /* prefered method is set by option  */
385   response.UseNT = !ms_lanman;
386 #else
387   response.UseNT = 1;
388 #endif
389 
390   BCOPY(&response, cstate->response, MS_CHAP_RESPONSE_LEN);
391   cstate->resp_length = MS_CHAP_RESPONSE_LEN;
392 }
393 
394 #endif /* MSCHAP_SUPPORT */
395 
396 #endif /* PPP_SUPPORT */
397