xnu-1228.tar.gz

[apple/xnu.git] / 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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/*
 * 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;
}