1 /* mcookie.c -- Generates random numbers for xauth
2 * Created: Fri Feb 3 10:42:48 1995 by faith@cs.unc.edu
3 * Revised: Fri Mar 19 07:48:01 1999 by faith@acm.org
4 * Public Domain 1995, 1999 Rickard E. Faith (faith@acm.org)
5 * This program comes with ABSOLUTELY NO WARRANTY.
6 *
7 * $Id: mcookie.c,v 1.5 1997/07/06 00:13:06 aebr Exp $
8 *
9 * This program gathers some random bits of data and used the MD5
10 * message-digest algorithm to generate a 128-bit hexadecimal number for
11 * use with xauth(1).
12 *
13 * NOTE: Unless /dev/random is available, this program does not actually
14 * gather 128 bits of random information, so the magic cookie generated
15 * will be considerably easier to guess than one might expect.
16 *
17 * 1999-02-22 Arkadiusz Mi�kiewicz <misiek@pld.ORG.PL>
18 * - added Native Language Support
19 * 1999-03-21 aeb: Added some fragments of code from Colin Plumb.
20 *
21 */
22
23 #include <stdio.h>
24 #include <stdlib.h>
25 #include <fcntl.h>
26 #include <sys/time.h>
27 #include <time.h>
28 #include <unistd.h>
29
30 #define BUFFERSIZE 4096
31
32
33 #ifndef MD5_H
34 #define MD5_H
35
36 #if defined (__alpha__) || defined (__ia64__) || defined (__x86_64__)
37 typedef unsigned int uint32;
38 #else
39 typedef unsigned long uint32;
40 #endif
41
42 struct MD5Context {
43 uint32 buf[4];
44 uint32 bits[2];
45 unsigned char in[64];
46 };
47
48 void MD5Init(struct MD5Context *context);
49 void MD5Update(struct MD5Context *context, unsigned char const *buf,
50 unsigned len);
51 void MD5Final(unsigned char digest[16], struct MD5Context *context);
52 void MD5Transform(uint32 buf[4], uint32 const in[16]);
53
54 /*
55 * This is needed to make RSAREF happy on some MS-DOS compilers.
56 */
57 typedef struct MD5Context MD5_CTX;
58
59 #endif /* !MD5_H */
60
61
62
63 /*
64 * This code implements the MD5 message-digest algorithm.
65 * The algorithm is due to Ron Rivest. This code was
66 * written by Colin Plumb in 1993, no copyright is claimed.
67 * This code is in the public domain; do with it what you wish.
68 *
69 * Equivalent code is available from RSA Data Security, Inc.
70 * This code has been tested against that, and is equivalent,
71 * except that you don't need to include two pages of legalese
72 * with every copy.
73 *
74 * To compute the message digest of a chunk of bytes, declare an
75 * MD5Context structure, pass it to MD5Init, call MD5Update as
76 * needed on buffers full of bytes, and then call MD5Final, which
77 * will fill a supplied 16-byte array with the digest.
78 */
79 #include <string.h> /* for memcpy() */
80 #include <endian.h>
81
82 #if __BYTE_ORDER == __LITTLE_ENDIAN
83 #define byteReverse(buf, len) /* Nothing */
84 #else
85 void byteReverse(unsigned char *buf, unsigned longs);
86
87 /*
88 * Note: this code is harmless on little-endian machines.
89 */
byteReverse(unsigned char * buf,unsigned longs)90 void byteReverse(unsigned char *buf, unsigned longs)
91 {
92 uint32 t;
93 do {
94 t = (uint32) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
95 ((unsigned) buf[1] << 8 | buf[0]);
96 *(uint32 *) buf = t;
97 buf += 4;
98 } while (--longs);
99 }
100 #endif
101
102 /*
103 * Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
104 * initialization constants.
105 */
MD5Init(struct MD5Context * ctx)106 void MD5Init(struct MD5Context *ctx)
107 {
108 ctx->buf[0] = 0x67452301;
109 ctx->buf[1] = 0xefcdab89;
110 ctx->buf[2] = 0x98badcfe;
111 ctx->buf[3] = 0x10325476;
112
113 ctx->bits[0] = 0;
114 ctx->bits[1] = 0;
115 }
116
117 /*
118 * Update context to reflect the concatenation of another buffer full
119 * of bytes.
120 */
MD5Update(struct MD5Context * ctx,unsigned char const * buf,unsigned len)121 void MD5Update(struct MD5Context *ctx, unsigned char const *buf, unsigned len)
122 {
123 uint32 t;
124
125 /* Update bitcount */
126
127 t = ctx->bits[0];
128 if ((ctx->bits[0] = t + ((uint32) len << 3)) < t)
129 ctx->bits[1]++; /* Carry from low to high */
130 ctx->bits[1] += len >> 29;
131
132 t = (t >> 3) & 0x3f; /* Bytes already in shsInfo->data */
133
134 /* Handle any leading odd-sized chunks */
135
136 if (t) {
137 unsigned char *p = (unsigned char *) ctx->in + t;
138
139 t = 64 - t;
140 if (len < t) {
141 memcpy(p, buf, len);
142 return;
143 }
144 memcpy(p, buf, t);
145 byteReverse(ctx->in, 16);
146 MD5Transform(ctx->buf, (uint32 *) ctx->in);
147 buf += t;
148 len -= t;
149 }
150 /* Process data in 64-byte chunks */
151
152 while (len >= 64) {
153 memcpy(ctx->in, buf, 64);
154 byteReverse(ctx->in, 16);
155 MD5Transform(ctx->buf, (uint32 *) ctx->in);
156 buf += 64;
157 len -= 64;
158 }
159
160 /* Handle any remaining bytes of data. */
161
162 memcpy(ctx->in, buf, len);
163 }
164
165 /*
166 * Final wrapup - pad to 64-byte boundary with the bit pattern
167 * 1 0* (64-bit count of bits processed, MSB-first)
168 */
MD5Final(unsigned char digest[16],struct MD5Context * ctx)169 void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
170 {
171 unsigned count;
172 unsigned char *p;
173
174 /* Compute number of bytes mod 64 */
175 count = (ctx->bits[0] >> 3) & 0x3F;
176
177 /* Set the first char of padding to 0x80. This is safe since there is
178 always at least one byte free */
179 p = ctx->in + count;
180 *p++ = 0x80;
181
182 /* Bytes of padding needed to make 64 bytes */
183 count = 64 - 1 - count;
184
185 /* Pad out to 56 mod 64 */
186 if (count < 8) {
187 /* Two lots of padding: Pad the first block to 64 bytes */
188 memset(p, 0, count);
189 byteReverse(ctx->in, 16);
190 MD5Transform(ctx->buf, (uint32 *) ctx->in);
191
192 /* Now fill the next block with 56 bytes */
193 memset(ctx->in, 0, 56);
194 } else {
195 /* Pad block to 56 bytes */
196 memset(p, 0, count - 8);
197 }
198 byteReverse(ctx->in, 14);
199
200 /* Append length in bits and transform */
201 ((uint32 *) ctx->in)[14] = ctx->bits[0];
202 ((uint32 *) ctx->in)[15] = ctx->bits[1];
203
204 MD5Transform(ctx->buf, (uint32 *) ctx->in);
205 byteReverse((unsigned char *) ctx->buf, 4);
206 memcpy(digest, ctx->buf, 16);
207 memset(ctx, 0, sizeof(*ctx)); /* In case it's sensitive */
208 }
209
210 /* The four core functions - F1 is optimized somewhat */
211
212 /* #define F1(x, y, z) (x & y | ~x & z) */
213 #define F1(x, y, z) (z ^ (x & (y ^ z)))
214 #define F2(x, y, z) F1(z, x, y)
215 #define F3(x, y, z) (x ^ y ^ z)
216 #define F4(x, y, z) (y ^ (x | ~z))
217
218 /* This is the central step in the MD5 algorithm. */
219 #define MD5STEP(f, w, x, y, z, data, s) \
220 ( w += f(x, y, z) + data, w = w<<s | w>>(32-s), w += x )
221
222 /*
223 * The core of the MD5 algorithm, this alters an existing MD5 hash to
224 * reflect the addition of 16 longwords of new data. MD5Update blocks
225 * the data and converts bytes into longwords for this routine.
226 */
MD5Transform(uint32 buf[4],uint32 const in[16])227 void MD5Transform(uint32 buf[4], uint32 const in[16])
228 {
229 register uint32 a, b, c, d;
230
231 a = buf[0];
232 b = buf[1];
233 c = buf[2];
234 d = buf[3];
235
236 MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
237 MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
238 MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
239 MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
240 MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
241 MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
242 MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
243 MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
244 MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
245 MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
246 MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
247 MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
248 MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
249 MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
250 MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
251 MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
252
253 MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
254 MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
255 MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
256 MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
257 MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
258 MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
259 MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
260 MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
261 MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
262 MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
263 MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
264 MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
265 MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
266 MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
267 MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
268 MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
269
270 MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
271 MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
272 MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
273 MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
274 MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
275 MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
276 MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
277 MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
278 MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
279 MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
280 MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
281 MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
282 MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
283 MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
284 MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
285 MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
286
287 MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
288 MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
289 MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
290 MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
291 MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
292 MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
293 MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
294 MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
295 MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
296 MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
297 MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
298 MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
299 MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
300 MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
301 MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
302 MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
303
304 buf[0] += a;
305 buf[1] += b;
306 buf[2] += c;
307 buf[3] += d;
308 }
309
310
311
312
313 struct rngs {
314 const char *path;
315 int minlength, maxlength;
316 } rngs[] = {
317 { "/dev/random", 16, 16 }, /* 16 bytes = 128 bits suffice */
318 { "/proc/interrupts", 0, 0 },
319 { "/proc/slabinfo", 0, 0 },
320 { "/proc/stat", 0, 0 },
321 { "/dev/urandom", 32, 64 },
322 };
323 #define RNGS (sizeof(rngs)/sizeof(struct rngs))
324
325 int Verbose = 0;
326
327 /* The basic function to hash a file */
328 static off_t
hash_file(struct MD5Context * ctx,int fd)329 hash_file(struct MD5Context *ctx, int fd)
330 {
331 off_t count = 0;
332 ssize_t r;
333 unsigned char buf[BUFFERSIZE];
334
335 while ((r = read(fd, buf, sizeof(buf))) > 0) {
336 MD5Update(ctx, buf, r);
337 count += r;
338 }
339 /* Separate files with a null byte */
340 buf[0] = 0;
341 MD5Update(ctx, buf, 1);
342 return count;
343 }
344
main(int argc,char ** argv)345 int main( int argc, char **argv )
346 {
347 int i;
348 struct MD5Context ctx;
349 unsigned char digest[16];
350 unsigned char buf[BUFFERSIZE];
351 int fd;
352 int c;
353 pid_t pid;
354 char *file = NULL;
355 int r;
356 struct timeval tv;
357 struct timezone tz;
358
359 while ((c = getopt( argc, argv, "vf:" )) != -1)
360 switch (c) {
361 case 'v': ++Verbose; break;
362 case 'f': file = optarg; break;
363 }
364
365 MD5Init( &ctx );
366
367 gettimeofday( &tv, &tz );
368 MD5Update( &ctx, (unsigned char *)&tv, sizeof( tv ) );
369 pid = getppid();
370 MD5Update( &ctx, (unsigned char *)&pid, sizeof( pid ));
371 pid = getpid();
372 MD5Update( &ctx, (unsigned char *)&pid, sizeof( pid ));
373
374 if (file) {
375 int count = 0;
376
377 if (file[0] == '-' && !file[1])
378 fd = fileno(stdin);
379 else
380 fd = open( file, O_RDONLY );
381
382 if (fd < 0) {
383 fprintf( stderr, "Could not open %s\n", file );
384 } else {
385 count = hash_file( &ctx, fd );
386 if (Verbose)
387 fprintf( stderr, "Got %d bytes from %s\n", count, file );
388
389 if (file[0] != '-' || file[1]) close( fd );
390 }
391 }
392
393 for (i = 0; i < RNGS; i++) {
394 if ((fd = open( rngs[i].path, O_RDONLY|O_NONBLOCK )) >= 0) {
395 int count = sizeof(buf);
396
397 if (rngs[i].maxlength && count > rngs[i].maxlength)
398 count = rngs[i].maxlength;
399 r = read( fd, buf, count );
400 if (r > 0)
401 MD5Update( &ctx, buf, r );
402 else
403 r = 0;
404 close( fd );
405 if (Verbose)
406 fprintf( stderr, "Got %d bytes from %s\n", r, rngs[i].path );
407 if (rngs[i].minlength && r >= rngs[i].minlength)
408 break;
409 } else if (Verbose)
410 fprintf( stderr, "Could not open %s\n", rngs[i].path );
411 }
412
413 MD5Final( digest, &ctx );
414 for (i = 0; i < 16; i++) printf( "%02x", digest[i] );
415 putchar ( '\n' );
416
417 /*
418 * The following is important for cases like disk full, so shell scripts
419 * can bomb out properly rather than think they succeeded.
420 */
421 if (fflush(stdout) < 0 || fclose(stdout) < 0)
422 return 1;
423
424 return 0;
425 }
426