/* mcookie.c -- Generates random numbers for xauth * Created: Fri Feb 3 10:42:48 1995 by faith@cs.unc.edu * Revised: Fri Mar 19 07:48:01 1999 by faith@acm.org * Public Domain 1995, 1999 Rickard E. Faith (faith@acm.org) * This program comes with ABSOLUTELY NO WARRANTY. * * $Id: mcookie.c,v 1.5 1997/07/06 00:13:06 aebr Exp $ * * This program gathers some random bits of data and used the MD5 * message-digest algorithm to generate a 128-bit hexadecimal number for * use with xauth(1). * * NOTE: Unless /dev/random is available, this program does not actually * gather 128 bits of random information, so the magic cookie generated * will be considerably easier to guess than one might expect. * * 1999-02-22 Arkadiusz Mi¶kiewicz * - added Native Language Support * 1999-03-21 aeb: Added some fragments of code from Colin Plumb. * */ #include #include #include #include #include #include #define BUFFERSIZE 4096 #ifndef MD5_H #define MD5_H #if defined (__alpha__) || defined (__ia64__) || defined (__x86_64__) typedef unsigned int uint32; #else typedef unsigned long uint32; #endif struct MD5Context { uint32 buf[4]; uint32 bits[2]; unsigned char in[64]; }; void MD5Init(struct MD5Context *context); void MD5Update(struct MD5Context *context, unsigned char const *buf, unsigned len); void MD5Final(unsigned char digest[16], struct MD5Context *context); void MD5Transform(uint32 buf[4], uint32 const in[16]); /* * This is needed to make RSAREF happy on some MS-DOS compilers. */ typedef struct MD5Context MD5_CTX; #endif /* !MD5_H */ /* * This code implements the MD5 message-digest algorithm. * The algorithm is due to Ron Rivest. This code was * written by Colin Plumb in 1993, no copyright is claimed. * This code is in the public domain; do with it what you wish. * * Equivalent code is available from RSA Data Security, Inc. * This code has been tested against that, and is equivalent, * except that you don't need to include two pages of legalese * with every copy. * * To compute the message digest of a chunk of bytes, declare an * MD5Context structure, pass it to MD5Init, call MD5Update as * needed on buffers full of bytes, and then call MD5Final, which * will fill a supplied 16-byte array with the digest. */ #include /* for memcpy() */ #include #if __BYTE_ORDER == __LITTLE_ENDIAN #define byteReverse(buf, len) /* Nothing */ #else void byteReverse(unsigned char *buf, unsigned longs); /* * Note: this code is harmless on little-endian machines. */ void byteReverse(unsigned char *buf, unsigned longs) { uint32 t; do { t = (uint32) ((unsigned) buf[3] << 8 | buf[2]) << 16 | ((unsigned) buf[1] << 8 | buf[0]); *(uint32 *) buf = t; buf += 4; } while (--longs); } #endif /* * Start MD5 accumulation. Set bit count to 0 and buffer to mysterious * initialization constants. */ void MD5Init(struct MD5Context *ctx) { ctx->buf[0] = 0x67452301; ctx->buf[1] = 0xefcdab89; ctx->buf[2] = 0x98badcfe; ctx->buf[3] = 0x10325476; ctx->bits[0] = 0; ctx->bits[1] = 0; } /* * Update context to reflect the concatenation of another buffer full * of bytes. */ void MD5Update(struct MD5Context *ctx, unsigned char const *buf, unsigned len) { uint32 t; /* Update bitcount */ t = ctx->bits[0]; if ((ctx->bits[0] = t + ((uint32) len << 3)) < t) ctx->bits[1]++; /* Carry from low to high */ ctx->bits[1] += len >> 29; t = (t >> 3) & 0x3f; /* Bytes already in shsInfo->data */ /* Handle any leading odd-sized chunks */ if (t) { unsigned char *p = (unsigned char *) ctx->in + t; t = 64 - t; if (len < t) { memcpy(p, buf, len); return; } memcpy(p, buf, t); byteReverse(ctx->in, 16); MD5Transform(ctx->buf, (uint32 *) ctx->in); buf += t; len -= t; } /* Process data in 64-byte chunks */ while (len >= 64) { memcpy(ctx->in, buf, 64); byteReverse(ctx->in, 16); MD5Transform(ctx->buf, (uint32 *) ctx->in); buf += 64; len -= 64; } /* Handle any remaining bytes of data. */ memcpy(ctx->in, buf, len); } /* * Final wrapup - pad to 64-byte boundary with the bit pattern * 1 0* (64-bit count of bits processed, MSB-first) */ void MD5Final(unsigned char digest[16], struct MD5Context *ctx) { unsigned count; unsigned char *p; /* Compute number of bytes mod 64 */ count = (ctx->bits[0] >> 3) & 0x3F; /* Set the first char of padding to 0x80. This is safe since there is always at least one byte free */ p = ctx->in + count; *p++ = 0x80; /* Bytes of padding needed to make 64 bytes */ count = 64 - 1 - count; /* Pad out to 56 mod 64 */ if (count < 8) { /* Two lots of padding: Pad the first block to 64 bytes */ memset(p, 0, count); byteReverse(ctx->in, 16); MD5Transform(ctx->buf, (uint32 *) ctx->in); /* Now fill the next block with 56 bytes */ memset(ctx->in, 0, 56); } else { /* Pad block to 56 bytes */ memset(p, 0, count - 8); } byteReverse(ctx->in, 14); /* Append length in bits and transform */ ((uint32 *) ctx->in)[14] = ctx->bits[0]; ((uint32 *) ctx->in)[15] = ctx->bits[1]; MD5Transform(ctx->buf, (uint32 *) ctx->in); byteReverse((unsigned char *) ctx->buf, 4); memcpy(digest, ctx->buf, 16); memset(ctx, 0, sizeof(*ctx)); /* In case it's sensitive */ } /* The four core functions - F1 is optimized somewhat */ /* #define F1(x, y, z) (x & y | ~x & z) */ #define F1(x, y, z) (z ^ (x & (y ^ z))) #define F2(x, y, z) F1(z, x, y) #define F3(x, y, z) (x ^ y ^ z) #define F4(x, y, z) (y ^ (x | ~z)) /* This is the central step in the MD5 algorithm. */ #define MD5STEP(f, w, x, y, z, data, s) \ ( w += f(x, y, z) + data, w = w<>(32-s), w += x ) /* * The core of the MD5 algorithm, this alters an existing MD5 hash to * reflect the addition of 16 longwords of new data. MD5Update blocks * the data and converts bytes into longwords for this routine. */ void MD5Transform(uint32 buf[4], uint32 const in[16]) { register uint32 a, b, c, d; a = buf[0]; b = buf[1]; c = buf[2]; d = buf[3]; MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7); MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12); MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17); MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22); MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7); MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12); MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17); MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22); MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7); MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12); MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17); MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22); MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7); MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12); MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17); MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22); MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5); MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9); MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14); MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20); MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5); MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9); MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14); MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20); MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5); MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9); MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14); MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20); MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5); MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9); MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14); MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20); MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4); MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11); MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16); MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23); MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4); MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11); MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16); MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23); MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4); MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11); MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16); MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23); MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4); MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11); MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16); MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23); MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6); MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10); MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15); MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21); MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6); MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10); MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15); MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21); MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6); MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10); MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15); MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21); MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6); MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10); MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15); MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21); buf[0] += a; buf[1] += b; buf[2] += c; buf[3] += d; } struct rngs { const char *path; int minlength, maxlength; } rngs[] = { { "/dev/random", 16, 16 }, /* 16 bytes = 128 bits suffice */ { "/proc/interrupts", 0, 0 }, { "/proc/slabinfo", 0, 0 }, { "/proc/stat", 0, 0 }, { "/dev/urandom", 32, 64 }, }; #define RNGS (sizeof(rngs)/sizeof(struct rngs)) int Verbose = 0; /* The basic function to hash a file */ static off_t hash_file(struct MD5Context *ctx, int fd) { off_t count = 0; ssize_t r; unsigned char buf[BUFFERSIZE]; while ((r = read(fd, buf, sizeof(buf))) > 0) { MD5Update(ctx, buf, r); count += r; } /* Separate files with a null byte */ buf[0] = 0; MD5Update(ctx, buf, 1); return count; } int main( int argc, char **argv ) { int i; struct MD5Context ctx; unsigned char digest[16]; unsigned char buf[BUFFERSIZE]; int fd; int c; pid_t pid; char *file = NULL; int r; struct timeval tv; struct timezone tz; while ((c = getopt( argc, argv, "vf:" )) != -1) switch (c) { case 'v': ++Verbose; break; case 'f': file = optarg; break; } MD5Init( &ctx ); gettimeofday( &tv, &tz ); MD5Update( &ctx, (unsigned char *)&tv, sizeof( tv ) ); pid = getppid(); MD5Update( &ctx, (unsigned char *)&pid, sizeof( pid )); pid = getpid(); MD5Update( &ctx, (unsigned char *)&pid, sizeof( pid )); if (file) { int count = 0; if (file[0] == '-' && !file[1]) fd = fileno(stdin); else fd = open( file, O_RDONLY ); if (fd < 0) { fprintf( stderr, "Could not open %s\n", file ); } else { count = hash_file( &ctx, fd ); if (Verbose) fprintf( stderr, "Got %d bytes from %s\n", count, file ); if (file[0] != '-' || file[1]) close( fd ); } } for (i = 0; i < RNGS; i++) { if ((fd = open( rngs[i].path, O_RDONLY|O_NONBLOCK )) >= 0) { int count = sizeof(buf); if (rngs[i].maxlength && count > rngs[i].maxlength) count = rngs[i].maxlength; r = read( fd, buf, count ); if (r > 0) MD5Update( &ctx, buf, r ); else r = 0; close( fd ); if (Verbose) fprintf( stderr, "Got %d bytes from %s\n", r, rngs[i].path ); if (rngs[i].minlength && r >= rngs[i].minlength) break; } else if (Verbose) fprintf( stderr, "Could not open %s\n", rngs[i].path ); } MD5Final( digest, &ctx ); for (i = 0; i < 16; i++) printf( "%02x", digest[i] ); putchar ( '\n' ); /* * The following is important for cases like disk full, so shell scripts * can bomb out properly rather than think they succeeded. */ if (fflush(stdout) < 0 || fclose(stdout) < 0) return 1; return 0; }