md5c.c

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/*-
 * MD5C.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.
 */
 
/*
 * This file should be kept in sync with src/lib/libmd/md5c.c
 */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
 
#include <sys/types.h>
 
#ifdef _KERNEL
#include <sys/systm.h>
#else
#include <string.h>
#endif
 
#include <machine/endian.h>
#include <sys/endian.h>
#include <sys/md5.h>
 
static void MD5Transform(uint32_t [4], const unsigned char [64]);
 
#if (BYTE_ORDER == LITTLE_ENDIAN)
#define Encode memcpy
#define Decode memcpy
#else 
 
/*
 * Encodes input (uint32_t) into output (unsigned char). Assumes len is
 * a multiple of 4.
 */
 
static void
Encode (unsigned char *output, uint32_t *input, unsigned int len)
{
        unsigned int i;
        uint32_t ip;
 
        for (i = 0; i < len / 4; i++) {
                ip = input[i];
                *output++ = ip;
                *output++ = ip >> 8;
                *output++ = ip >> 16;
                *output++ = ip >> 24;
        }
}
 
/*
 * Decodes input (unsigned char) into output (uint32_t). Assumes len is
 * a multiple of 4.
 */
 
static void
Decode (uint32_t *output, const unsigned char *input, unsigned int len)
{
        unsigned int i;
 
        for (i = 0; i < len; i += 4) { 
                *output++ = input[i] | (input[i+1] << 8) | (input[i+2] << 16) |
                    (input[i+3] << 24);
        }
}
#endif
 
static unsigned char PADDING[64] = {
  0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
 
/* F, G, H and I are basic MD5 functions. */
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))
 
/* 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) + (uint32_t)(ac); \
        (a) = ROTATE_LEFT ((a), (s)); \
        (a) += (b); \
        }
#define GG(a, b, c, d, x, s, ac) { \
        (a) += G ((b), (c), (d)) + (x) + (uint32_t)(ac); \
        (a) = ROTATE_LEFT ((a), (s)); \
        (a) += (b); \
        }
#define HH(a, b, c, d, x, s, ac) { \
        (a) += H ((b), (c), (d)) + (x) + (uint32_t)(ac); \
        (a) = ROTATE_LEFT ((a), (s)); \
        (a) += (b); \
        }
#define II(a, b, c, d, x, s, ac) { \
        (a) += I ((b), (c), (d)) + (x) + (uint32_t)(ac); \
        (a) = ROTATE_LEFT ((a), (s)); \
        (a) += (b); \
        }
 
/* MD5 initialization. Begins an MD5 operation, writing a new context. */
 
void
MD5Init (context)
        MD5_CTX *context;
{
 
        context->count[0] = context->count[1] = 0;
 
        /* Load magic initialization constants.  */
        context->state[0] = 0x67452301;
        context->state[1] = 0xefcdab89;
        context->state[2] = 0x98badcfe;
        context->state[3] = 0x10325476;
}
 
/* 
 * MD5 block update operation. Continues an MD5 message-digest
 * operation, processing another message block, and updating the
 * context.
 */
 
void
MD5Update (context, in, inputLen)
        MD5_CTX *context;
        const void *in;
        unsigned int inputLen;
{
        unsigned int i, index, partLen;
        const unsigned char *input = in;
 
        /* Compute number of bytes mod 64 */
        index = (unsigned int)((context->count[0] >> 3) & 0x3F);
 
        /* Update number of bits */
        if ((context->count[0] += ((uint32_t)inputLen << 3))
            < ((uint32_t)inputLen << 3))
                context->count[1]++;
        context->count[1] += ((uint32_t)inputLen >> 29);
 
        partLen = 64 - index;
 
        /* Transform as many times as possible. */
        if (inputLen >= partLen) {
                memcpy((void *)&context->buffer[index], (const void *)input,
                    partLen);
                MD5Transform (context->state, context->buffer);
 
                for (i = partLen; i + 63 < inputLen; i += 64)
                        MD5Transform (context->state, &input[i]);
 
                index = 0;
        }
        else
                i = 0;
 
        /* Buffer remaining input */
        memcpy ((void *)&context->buffer[index], (const void *)&input[i],
            inputLen-i);
}
 
/*
 * MD5 padding. Adds padding followed by original length.
 */
 
static void
MD5Pad (MD5_CTX *context)
{
        unsigned char bits[8];
        unsigned int index, padLen;
 
        /* Save number of bits */
        Encode (bits, context->count, 8);
 
        /* Pad out to 56 mod 64. */
        index = (unsigned int)((context->count[0] >> 3) & 0x3f);
        padLen = (index < 56) ? (56 - index) : (120 - index);
        MD5Update (context, PADDING, padLen);
 
        /* Append length (before padding) */
        MD5Update (context, bits, 8);
}
 
/*
 * MD5 finalization. Ends an MD5 message-digest operation, writing the
 * the message digest and zeroizing the context.
 */
 
void
MD5Final(unsigned char digest[static MD5_DIGEST_LENGTH], MD5_CTX *context)
{
        /* Do padding. */
        MD5Pad (context);
 
        /* Store state in digest */
        Encode (digest, context->state, MD5_DIGEST_LENGTH);
 
        /* Zeroize sensitive information. */
        memset (context, 0, sizeof (*context));
}
 
/* MD5 basic transformation. Transforms state based on block. */
 
static void
MD5Transform (state, block)
        uint32_t state[4];
        const unsigned char block[64];
{
        uint32_t a = state[0], b = state[1], c = state[2], d = state[3], x[16];
 
        Decode (x, block, 64);
 
        /* Round 1 */
#define S11 7
#define S12 12
#define S13 17
#define S14 22
        FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
        FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
        FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
        FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
        FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
        FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
        FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
        FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
        FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
        FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
        FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
        FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
        FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
        FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
        FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
        FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */
 
        /* Round 2 */
#define S21 5
#define S22 9
#define S23 14
#define S24 20
        GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
        GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
        GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
        GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
        GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
        GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
        GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
        GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
        GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
        GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
        GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
        GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
        GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
        GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
        GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
        GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */
 
        /* Round 3 */
#define S31 4
#define S32 11
#define S33 16
#define S34 23
        HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
        HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
        HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
        HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
        HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
        HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
        HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
        HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
        HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
        HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
        HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
        HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
        HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
        HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
        HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
        HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */
 
        /* Round 4 */
#define S41 6
#define S42 10
#define S43 15
#define S44 21
        II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
        II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
        II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
        II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
        II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
        II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
        II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
        II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
        II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
        II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
        II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
        II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
        II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
        II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
        II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
        II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */
 
        state[0] += a;
        state[1] += b;
        state[2] += c;
        state[3] += d;
 
        /* Zeroize sensitive information. */
        memset ((void *)x, 0, sizeof (x));
}