libinstpatch-1.1.6/libinstpatch/md5.c

/*
 * 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
 * IpatchMD5 structure, pass it to ipatch_md5_init, call ipatch_md5_update as
 * needed on buffers full of bytes, and then call ipatch_md5_final, which
 * will fill a supplied 16-byte array with the digest.
 *
 * Changed so as no longer to depend on Colin Plumb's `usual.h' header
 * definitions; now uses stuff from dpkg's config.h.
 *  - Ian Jackson <ijackson@nyx.cs.du.edu>.
 * Still in the public domain.
 *
 * Josh Coalson: made some changes to integrate with libFLAC.
 * Still in the public domain.
 *
 * Josh Green: made some changes to integrate with libInstPatch.
 * Still in the public domain.
 */
/**
 * SECTION: md5
 * @short_description: MD5 hashing functions
 * @see_also:
 * @stability: Stable
 */
#include <stdlib.h>		/* for malloc() */
#include <string.h>		/* for memcpy() */
#include <glib.h>

#include "md5.h"

/* 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,in,s) \
	 (w += f(x,y,z) + in, w = (w<<s | w>>(32-s)) + x)

/*
 * The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data.  ipatch_md5_update blocks
 * the data and converts bytes into longwords for this routine.
 */
static inline void
MD5Transform(guint32 buf[4], guint32 const in[16])
{
    register guint32 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;
}

static inline void
byteSwap(guint32 *buf, unsigned words)
{
    guint8 *p = (guint8 *)buf;

    if(G_BYTE_ORDER != G_BIG_ENDIAN)
    {
        return;
    }

    do
    {
        *buf++ = (guint32)((unsigned)p[3] << 8 | p[2]) << 16
                 | ((unsigned)p[1] << 8 | p[0]);
        p += 4;
    }
    while(--words);
}

/**
 * ipatch_md5_init: (skip)
 * @ctx: MD5 context
 *
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
void
ipatch_md5_init(IpatchMD5 *ctx)
{
    ctx->buf[0] = 0x67452301;
    ctx->buf[1] = 0xefcdab89;
    ctx->buf[2] = 0x98badcfe;
    ctx->buf[3] = 0x10325476;

    ctx->bytes[0] = 0;
    ctx->bytes[1] = 0;
}

/*
 * ipatch_md5_update: (skip)
 * @ctx: MD5 context
 * @buf: Buffer of data
 * @len: Length of data in @buf
 *
 * Update MD5 context to reflect the concatenation of another buffer full
 * of bytes.
 */
void
ipatch_md5_update(IpatchMD5 *ctx, guint8 const *buf, unsigned len)
{
    guint32 t;

    /* Update byte count */

    t = ctx->bytes[0];

    if((ctx->bytes[0] = t + len) < t)
    {
        ctx->bytes[1]++;    /* Carry from low to high */
    }

    t = 64 - (t & 0x3f);	/* Space available in ctx->in (at least 1) */

    if(t > len)
    {
        memcpy((guint8 *)ctx->in + 64 - t, buf, len);
        return;
    }

    /* First chunk is an odd size */
    memcpy((guint8 *)ctx->in + 64 - t, buf, t);
    byteSwap(ctx->in, 16);
    MD5Transform(ctx->buf, ctx->in);
    buf += t;
    len -= t;

    /* Process data in 64-byte chunks */
    while(len >= 64)
    {
        memcpy(ctx->in, buf, 64);
        byteSwap(ctx->in, 16);
        MD5Transform(ctx->buf, ctx->in);
        buf += 64;
        len -= 64;
    }

    /* Handle any remaining bytes of data. */
    memcpy(ctx->in, buf, len);
}

/**
 * ipatch_md5_final: (skip)
 * @ctx: MD5 context
 * @digest: Buffer to store 16 byte MD5 digest into
 *
 * Final wrapup - pad to 64-byte boundary with the bit pattern
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
void
ipatch_md5_final(IpatchMD5 *ctx, guint8 digest[16])
{
    int count = ctx->bytes[0] & 0x3f;	/* Number of bytes in ctx->in */
    guint8 *p = (guint8 *)ctx->in + count;

    /* Set the first char of padding to 0x80.  There is always room. */
    *p++ = 0x80;

    /* Bytes of padding needed to make 56 bytes (-8..55) */
    count = 56 - 1 - count;

    if(count < 0)  	/* Padding forces an extra block */
    {
        memset(p, 0, count + 8);
        byteSwap(ctx->in, 16);
        MD5Transform(ctx->buf, ctx->in);
        p = (guint8 *)ctx->in;
        count = 56;
    }

    memset(p, 0, count);
    byteSwap(ctx->in, 14);

    /* Append length in bits and transform */
    ctx->in[14] = ctx->bytes[0] << 3;
    ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
    MD5Transform(ctx->buf, ctx->in);

    byteSwap(ctx->buf, 4);
    memcpy(digest, ctx->buf, 16);
    memset(ctx, 0, sizeof(*ctx));	/* In case it's sensitive */
}