FreeBSD/Linux Kernel Cross Reference
sys/libkern/crypto/md5.c

     /*
      * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
      *
      * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
      * 
      * This file contains Original Code and/or Modifications of Original Code
      * as defined in and that are subject to the Apple Public Source License
      * Version 2.0 (the 'License'). You may not use this file except in
      * compliance with the License. The rights granted to you under the License
     * may not be used to create, or enable the creation or redistribution of,
     * unlawful or unlicensed copies of an Apple operating system, or to
     * circumvent, violate, or enable the circumvention or violation of, any
     * terms of an Apple operating system software license agreement.
     * 
     * Please obtain a copy of the License at
     * http://www.opensource.apple.com/apsl/ and read it before using this file.
     * 
     * The Original Code and all software distributed under the License are
     * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
     * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
     * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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     * Please see the License for the specific language governing rights and
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     * 
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     */
    
    /*
     * MD5.C - RSA Data Security, Inc., MD5 message-digest algorithm
     *
     * Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
     * rights reserved.
     *
     * License to copy and use this software is granted provided that it
     * is identified as the "RSA Data Security, Inc. MD5 Message-Digest
     * Algorithm" in all material mentioning or referencing this software
     * or this function.
     *
     * License is also granted to make and use derivative works provided
     * that such works are identified as "derived from the RSA Data
     * Security, Inc. MD5 Message-Digest Algorithm" in all material
     * mentioning or referencing the derived work.
     *
     * RSA Data Security, Inc. makes no representations concerning either
     * the merchantability of this software or the suitability of this
     * software for any particular purpose. It is provided "as is"
     * without express or implied warranty of any kind.
     *
     * These notices must be retained in any copies of any part of this
     * documentation and/or software.
     *
     * This code is the same as the code published by RSA Inc.  It has been
     * edited for clarity and style only.
     */
    
    #include <sys/types.h>
    #include <sys/systm.h>
    #include <libkern/crypto/md5.h>
    
    #define memset(x, y, z) bzero(x, z);
    #define memcpy(x, y, z) bcopy(y, x, z)
    
    /*
     * The digest algorithm interprets the input message as a sequence of 32-bit
     * little-endian words.  We must reverse bytes in each word on PPC and other
     * big-endian platforms, but not on little-endian ones.  When we can, we try
     * to load each word at once.  We don't quite care about alignment, since
     * x86/x64 allows us to do 4-byte loads on non 4-byte aligned addresses,
     * and on PPC we do 1-byte loads anyway.
     *
     * We could check against __LITLE_ENDIAN__ to generalize the 4-byte load
     * optimization, but that might not tell us whether or not we need 4-byte
     * aligned loads.  Since we know that __i386__ and __x86_64__ are the two
     * little-endian architectures that are not alignment-restrictive, we check
     * explicitly against them below.  Note that the byte-reversing code for
     * big-endian will still work on little-endian, albeit much slower.
     */
    #if defined(__i386__) || defined(__x86_64__)
    #define FETCH_32(p)     (*(const u_int32_t *)(p))
    #else
    #define FETCH_32(p)                                             \
            (((u_int32_t)*((const u_int8_t *)(p))) |                \
            (((u_int32_t)*((const u_int8_t *)(p) + 1)) << 8) |      \
            (((u_int32_t)*((const u_int8_t *)(p) + 2)) << 16) |     \
            (((u_int32_t)*((const u_int8_t *)(p) + 3)) << 24))
    #endif /* __i386__ || __x86_64__ */
    
    /*
     * Encodes input (u_int32_t) into output (unsigned char). Assumes len is
     * a multiple of 4. This is not compatible with memcpy().
     */
    static void
    Encode(unsigned char *output, u_int32_t *input, unsigned int len)
    {
            unsigned int i, j;
    
            for (i = 0, j = 0; j < len; i++, j += 4) {
    #if defined(__i386__) || defined(__x86_64__)
                   *(u_int32_t *)(output + j) = input[i];
   #else
                   output[j] = input[i] & 0xff;
                   output[j + 1] = (input[i] >> 8) & 0xff;
                   output[j + 2] = (input[i] >> 16) & 0xff;
                   output[j + 3] = (input[i] >> 24) & 0xff;
   #endif /* __i386__ || __x86_64__ */
           }
   }
   
   static unsigned char PADDING[64] = { 0x80, /* zeros */ };
   
   /* F, G, H and I are basic MD5 functions. */
   #define F(x, y, z)      ((((y) ^ (z)) & (x)) ^ (z))
   #define G(x, y, z)      ((((x) ^ (y)) & (z)) ^ (y))
   #define H(x, y, z)      ((x) ^ (y) ^ (z))
   #define I(x, y, z)      (((~(z)) | (x)) ^ (y))
   
   /* ROTATE_LEFT rotates x left n bits. */
   #define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n))))
   
   /*
    * FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
    * Rotation is separate from addition to prevent recomputation.
    */
   #define FF(a, b, c, d, x, s, ac) {                                      \
           (a) += F((b), (c), (d)) + (x) + (unsigned long long)(ac);       \
           (a) = ROTATE_LEFT((a), (s));                                    \
           (a) += (b);                                                     \
   }
   
   #define GG(a, b, c, d, x, s, ac) {                                      \
           (a) += G((b), (c), (d)) + (x) + (unsigned long long)(ac);       \
           (a) = ROTATE_LEFT((a), (s));                                    \
           (a) += (b);                                                     \
   }
   
   #define HH(a, b, c, d, x, s, ac) {                                      \
           (a) += H((b), (c), (d)) + (x) + (unsigned long long)(ac);       \
           (a) = ROTATE_LEFT((a), (s));                                    \
           (a) += (b);                                                     \
   }
   
   #define II(a, b, c, d, x, s, ac) {                                      \
           (a) += I((b), (c), (d)) + (x) + (unsigned long long)(ac);       \
           (a) = ROTATE_LEFT((a), (s));                                    \
           (a) += (b);                                                     \
   }
   
   static void MD5Transform(u_int32_t, u_int32_t, u_int32_t, u_int32_t,
       const u_int8_t [64], MD5_CTX *);
   
   /*
    * MD5 initialization. Begins an MD5 operation, writing a new context.
    */
   void
   MD5Init(MD5_CTX *context)
   {
           context->count[0] = context->count[1] = 0;
   
           /* Load magic initialization constants.  */
           context->state[0] = 0x67452301UL;
           context->state[1] = 0xefcdab89UL;
           context->state[2] = 0x98badcfeUL;
           context->state[3] = 0x10325476UL;
   }
   
   /*
    * MD5 block update operation. Continues an MD5 message-digest
    * operation, processing another message block, and updating the
    * context.
    */
   void
   MD5Update(MD5_CTX *context, const void *inpp, unsigned int inputLen)
   {
           u_int32_t i, index, partLen;
           const unsigned char *input = (const unsigned char *)inpp;
   
           /* Compute number of bytes mod 64 */
           index = (context->count[0] >> 3) & 0x3F;
   
           /* Update number of bits */
           if ((context->count[0] += (inputLen << 3)) < (inputLen << 3))
                   context->count[1]++;
           context->count[1] += (inputLen >> 29);
   
           partLen = 64 - index;
   
           /* Transform as many times as possible. */
           i = 0;
           if (inputLen >= partLen) {
                   if (index != 0) {
                           memcpy(&context->buffer[index], input, partLen);
                           MD5Transform(context->state[0], context->state[1],
                               context->state[2], context->state[3],
                               context->buffer, context);
                           i = partLen;
                   }
   
                   for (; i + 63 < inputLen; i += 64)
                           MD5Transform(context->state[0], context->state[1],
                               context->state[2], context->state[3],
                               &input[i], context);
   
                   if (inputLen == i)
                           return;
   
                   index = 0;
           }
   
           /* Buffer remaining input */
           memcpy(&context->buffer[index], &input[i], inputLen - i);
   }
   
   /*
    * MD5 finalization. Ends an MD5 message-digest operation, writing the
    * the message digest and zeroizing the context.
    */
   void
   MD5Final(unsigned char digest[MD5_DIGEST_LENGTH], MD5_CTX *context)
   {
           unsigned char bits[8];
           u_int32_t index = (context->count[0] >> 3) & 0x3f;
   
           /* Save number of bits */
           Encode(bits, context->count, 8);
   
           /* Pad out to 56 mod 64. */
           MD5Update(context, PADDING, ((index < 56) ? 56 : 120) - index);
   
           /* Append length (before padding) */
           MD5Update(context, bits, 8);
   
           /* Store state in digest */
           Encode(digest, context->state, 16);
   
           /* Zeroize sensitive information. */
           memset(context, 0, sizeof (*context));
   }
   
   /*
    * MD5 basic transformation. Transforms state based on block.
    */
   static void
   MD5Transform(u_int32_t a, u_int32_t b, u_int32_t c, u_int32_t d,
       const u_int8_t block[64], MD5_CTX *context)
   {
           /* Register (instead of array) is a win in most cases */
           register u_int32_t x0, x1, x2, x3, x4, x5, x6, x7;
           register u_int32_t x8, x9, x10, x11, x12, x13, x14, x15;
   
           x15 = FETCH_32(block + 60);
           x14 = FETCH_32(block + 56);
           x13 = FETCH_32(block + 52);
           x12 = FETCH_32(block + 48);
           x11 = FETCH_32(block + 44);
           x10 = FETCH_32(block + 40);
           x9  = FETCH_32(block + 36);
           x8  = FETCH_32(block + 32);
           x7  = FETCH_32(block + 28);
           x6  = FETCH_32(block + 24);
           x5  = FETCH_32(block + 20);
           x4  = FETCH_32(block + 16);
           x3  = FETCH_32(block + 12);
           x2  = FETCH_32(block +  8);
           x1  = FETCH_32(block +  4);
           x0  = FETCH_32(block +  0);
   
           /* Round 1 */
   #define S11 7
   #define S12 12
   #define S13 17
   #define S14 22
           FF(a, b, c, d, x0,  S11, 0xd76aa478UL); /* 1 */
           FF(d, a, b, c, x1,  S12, 0xe8c7b756UL); /* 2 */
           FF(c, d, a, b, x2,  S13, 0x242070dbUL); /* 3 */
           FF(b, c, d, a, x3,  S14, 0xc1bdceeeUL); /* 4 */
           FF(a, b, c, d, x4,  S11, 0xf57c0fafUL); /* 5 */
           FF(d, a, b, c, x5,  S12, 0x4787c62aUL); /* 6 */
           FF(c, d, a, b, x6,  S13, 0xa8304613UL); /* 7 */
           FF(b, c, d, a, x7,  S14, 0xfd469501UL); /* 8 */
           FF(a, b, c, d, x8,  S11, 0x698098d8UL); /* 9 */
           FF(d, a, b, c, x9,  S12, 0x8b44f7afUL); /* 10 */
           FF(c, d, a, b, x10, S13, 0xffff5bb1UL); /* 11 */
           FF(b, c, d, a, x11, S14, 0x895cd7beUL); /* 12 */
           FF(a, b, c, d, x12, S11, 0x6b901122UL); /* 13 */
           FF(d, a, b, c, x13, S12, 0xfd987193UL); /* 14 */
           FF(c, d, a, b, x14, S13, 0xa679438eUL); /* 15 */
           FF(b, c, d, a, x15, S14, 0x49b40821UL); /* 16 */
   
           /* Round 2 */
   #define S21 5
   #define S22 9
   #define S23 14
   #define S24 20
           GG(a, b, c, d, x1,  S21, 0xf61e2562UL); /* 17 */
           GG(d, a, b, c, x6,  S22, 0xc040b340UL); /* 18 */
           GG(c, d, a, b, x11, S23, 0x265e5a51UL); /* 19 */
           GG(b, c, d, a, x0,  S24, 0xe9b6c7aaUL); /* 20 */
           GG(a, b, c, d, x5,  S21, 0xd62f105dUL); /* 21 */
           GG(d, a, b, c, x10, S22, 0x02441453UL); /* 22 */
           GG(c, d, a, b, x15, S23, 0xd8a1e681UL); /* 23 */
           GG(b, c, d, a, x4,  S24, 0xe7d3fbc8UL); /* 24 */
           GG(a, b, c, d, x9,  S21, 0x21e1cde6UL); /* 25 */
           GG(d, a, b, c, x14, S22, 0xc33707d6UL); /* 26 */
           GG(c, d, a, b, x3,  S23, 0xf4d50d87UL); /* 27 */
           GG(b, c, d, a, x8,  S24, 0x455a14edUL); /* 28 */
           GG(a, b, c, d, x13, S21, 0xa9e3e905UL); /* 29 */
           GG(d, a, b, c, x2,  S22, 0xfcefa3f8UL); /* 30 */
           GG(c, d, a, b, x7,  S23, 0x676f02d9UL); /* 31 */
           GG(b, c, d, a, x12, S24, 0x8d2a4c8aUL); /* 32 */
   
           /* Round 3 */
   #define S31 4
   #define S32 11
   #define S33 16
   #define S34 23
           HH(a, b, c, d, x5,  S31, 0xfffa3942UL); /* 33 */
           HH(d, a, b, c, x8,  S32, 0x8771f681UL); /* 34 */
           HH(c, d, a, b, x11, S33, 0x6d9d6122UL); /* 35 */
           HH(b, c, d, a, x14, S34, 0xfde5380cUL); /* 36 */
           HH(a, b, c, d, x1,  S31, 0xa4beea44UL); /* 37 */
           HH(d, a, b, c, x4,  S32, 0x4bdecfa9UL); /* 38 */
           HH(c, d, a, b, x7,  S33, 0xf6bb4b60UL); /* 39 */
           HH(b, c, d, a, x10, S34, 0xbebfbc70UL); /* 40 */
           HH(a, b, c, d, x13, S31, 0x289b7ec6UL); /* 41 */
           HH(d, a, b, c, x0,  S32, 0xeaa127faUL); /* 42 */
           HH(c, d, a, b, x3,  S33, 0xd4ef3085UL); /* 43 */
           HH(b, c, d, a, x6,  S34, 0x04881d05UL); /* 44 */
           HH(a, b, c, d, x9,  S31, 0xd9d4d039UL); /* 45 */
           HH(d, a, b, c, x12, S32, 0xe6db99e5UL); /* 46 */
           HH(c, d, a, b, x15, S33, 0x1fa27cf8UL); /* 47 */
           HH(b, c, d, a, x2,  S34, 0xc4ac5665UL); /* 48 */
   
           /* Round 4 */
   #define S41 6
   #define S42 10
   #define S43 15
   #define S44 21
           II(a, b, c, d, x0,  S41, 0xf4292244UL); /* 49 */
           II(d, a, b, c, x7,  S42, 0x432aff97UL); /* 50 */
           II(c, d, a, b, x14, S43, 0xab9423a7UL); /* 51 */
           II(b, c, d, a, x5,  S44, 0xfc93a039UL); /* 52 */
           II(a, b, c, d, x12, S41, 0x655b59c3UL); /* 53 */
           II(d, a, b, c, x3,  S42, 0x8f0ccc92UL); /* 54 */
           II(c, d, a, b, x10, S43, 0xffeff47dUL); /* 55 */
           II(b, c, d, a, x1,  S44, 0x85845dd1UL); /* 56 */
           II(a, b, c, d, x8,  S41, 0x6fa87e4fUL); /* 57 */
           II(d, a, b, c, x15, S42, 0xfe2ce6e0UL); /* 58 */
           II(c, d, a, b, x6,  S43, 0xa3014314UL); /* 59 */
           II(b, c, d, a, x13, S44, 0x4e0811a1UL); /* 60 */
           II(a, b, c, d, x4,  S41, 0xf7537e82UL); /* 61 */
           II(d, a, b, c, x11, S42, 0xbd3af235UL); /* 62 */
           II(c, d, a, b, x2,  S43, 0x2ad7d2bbUL); /* 63 */
           II(b, c, d, a, x9,  S44, 0xeb86d391UL); /* 64 */
   
           context->state[0] += a;
           context->state[1] += b;
           context->state[2] += c;
           context->state[3] += d;
   
           /* Zeroize sensitive information. */
           x15 = x14 = x13 = x12 = x11 = x10 = x9 = x8 = 0;
           x7 = x6 = x5 = x4 = x3 = x2 = x1 = x0 = 0;
   }

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