ap_md5c.c

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2000 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * .
 *
 * Portions of this software are based upon public domain software
 * originally written at the National Center for Supercomputing Applications,
 * University of Illinois, Urbana-Champaign.
 */

/*
 * The ap_MD5Encode() routine uses much code obtained from the FreeBSD 3.0
 * MD5 crypt() function, which is licenced as follows:
 * ----------------------------------------------------------------------------
 * "THE BEER-WARE LICENSE" (Revision 42):
 * <phk@login.dknet.dk> wrote this file.  As long as you retain this notice you
 * can do whatever you want with this stuff. If we meet some day, and you think
 * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
 * ----------------------------------------------------------------------------
 */

#include <string.h>

#include "ap_config.h"
#include "ap_md5.h"
#include "ap.h"
#ifdef CHARSET_EBCDIC
#include "ebcdic.h"
#endif /*CHARSET_EBCDIC*/
#if HAVE_CRYPT_H
#include <crypt.h>
#endif

/* Constants for MD5Transform routine.
 */

#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

static void MD5Transform(UINT4 state[4], const unsigned char block[64]);
static void Encode(unsigned char *output, const UINT4 *input,
		   unsigned int len);
static void Decode(UINT4 *output, const unsigned char *input,
		   unsigned int len);

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) + (UINT4)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define GG(a, b, c, d, x, s, ac) { \
 (a) += G ((b), (c), (d)) + (x) + (UINT4)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define HH(a, b, c, d, x, s, ac) { \
 (a) += H ((b), (c), (d)) + (x) + (UINT4)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define II(a, b, c, d, x, s, ac) { \
 (a) += I ((b), (c), (d)) + (x) + (UINT4)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }

/* MD5 initialization. Begins an MD5 operation, writing a new context.
 */
void ap_MD5Init(AP_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 ap_MD5Update(AP_MD5_CTX *context, const unsigned char *input,
			      unsigned int inputLen)
{
    unsigned int i, idx, partLen;

    /* Compute number of bytes mod 64 */
    idx = (unsigned int) ((context->count[0] >> 3) & 0x3F);

    /* Update number of bits */
    if ((context->count[0] += ((UINT4) inputLen << 3))
	< ((UINT4) inputLen << 3)) {
	context->count[1]++;
    }
    context->count[1] += (UINT4) inputLen >> 29;

    partLen = 64 - idx;

    /* Transform as many times as possible. */
#ifndef CHARSET_EBCDIC
    if (inputLen >= partLen) {
	memcpy(&context->buffer[idx], input, partLen);
	MD5Transform(context->state, context->buffer);

	for (i = partLen; i + 63 < inputLen; i += 64) {
	    MD5Transform(context->state, &input[i]);
	}

	idx = 0;
    }
    else {
	i = 0;
    }

    /* Buffer remaining input */
    memcpy(&context->buffer[idx], &input[i], inputLen - i);
#else /*CHARSET_EBCDIC*/
    if (inputLen >= partLen) {
	ebcdic2ascii(&context->buffer[idx], input, partLen);
	MD5Transform(context->state, context->buffer);

	for (i = partLen; i + 63 < inputLen; i += 64) {
	    unsigned char inp_tmp[64];
	    ebcdic2ascii(inp_tmp, &input[i], 64);
	    MD5Transform(context->state, inp_tmp);
	}

	idx = 0;
    }
    else {
	i = 0;
    }

    /* Buffer remaining input */
    ebcdic2ascii(&context->buffer[idx], &input[i], inputLen - i);
#endif /*CHARSET_EBCDIC*/
}

/* MD5 finalization. Ends an MD5 message-digest operation, writing the
   the message digest and zeroizing the context.
 */
void ap_MD5Final(unsigned char digest[16], AP_MD5_CTX *context)
{
    unsigned char bits[8];
    unsigned int idx, padLen;


    /* Save number of bits */
    Encode(bits, context->count, 8);

#ifdef CHARSET_EBCDIC
    /* XXX: @@@: In order to make this no more complex than necessary,
     * this kludge converts the bits[] array using the ascii-to-ebcdic
     * table, because the following ap_MD5Update() re-translates
     * its input (ebcdic-to-ascii).
     * Otherwise, we would have to pass a "conversion" flag to ap_MD5Update()
     */
    ascii2ebcdic(bits,bits,8);

    /* Since everything is converted to ascii within ap_MD5Update(), 
     * the initial 0x80 (PADDING[0]) must be stored as 0x20 
     */
    PADDING[0] = os_toebcdic[0x80];
#endif /*CHARSET_EBCDIC*/

    /* Pad out to 56 mod 64. */
    idx = (unsigned int) ((context->count[0] >> 3) & 0x3f);
    padLen = (idx < 56) ? (56 - idx) : (120 - idx);
    ap_MD5Update(context, (const unsigned char *)PADDING, padLen);

    /* Append length (before padding) */
    ap_MD5Update(context, (const unsigned char *)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(UINT4 state[4], const unsigned char block[64])
{
    UINT4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];

    Decode(x, block, 64);

    /* Round 1 */
    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 */
    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 */
    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 */
    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(x, 0, sizeof(x));
}

/* Encodes input (UINT4) into output (unsigned char). Assumes len is
   a multiple of 4.
 */
static void Encode(unsigned char *output, const UINT4 *input, unsigned int len)
{
    unsigned int i, j;
    UINT4 k;

    for (i = 0, j = 0; j < len; i++, j += 4) {
	k = input[i];
	output[j] = (unsigned char) (k & 0xff);
	output[j + 1] = (unsigned char) ((k >> 8) & 0xff);
	output[j + 2] = (unsigned char) ((k >> 16) & 0xff);
	output[j + 3] = (unsigned char) ((k >> 24) & 0xff);
    }
}

/* Decodes input (unsigned char) into output (UINT4). Assumes len is
 * a multiple of 4.
 */
static void Decode(UINT4 *output, const unsigned char *input, unsigned int len)
{
    unsigned int i, j;

    for (i = 0, j = 0; j < len; i++, j += 4)
	output[i] = ((UINT4) input[j]) | (((UINT4) input[j + 1]) << 8) |
	    (((UINT4) input[j + 2]) << 16) | (((UINT4) input[j + 3]) << 24);
}

/*
 * The following MD5 password encryption code was largely borrowed from
 * the FreeBSD 3.0 /usr/src/lib/libcrypt/crypt.c file, which is
 * licenced as stated at the top of this file.
 */
void ap_to64(char *s, unsigned long v, int n)
{
    static unsigned char itoa64[] =         /* 0 ... 63 => ASCII - 64 */
	"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

    while (--n >= 0) {
	*s++ = itoa64[v&0x3f];
	v >>= 6;
    }
}

void ap_MD5Encode(const unsigned char *pw,
			      const unsigned char *salt,
			      char *result, size_t nbytes)
{
    /*
     * Minimum size is 8 bytes for salt, plus 1 for the trailing NUL,
     * plus 4 for the '$' separators, plus the password hash itself.
     * Let's leave a goodly amount of leeway.
     */

    char passwd[120], *p;
    const unsigned char *sp, *ep;
    unsigned char final[16];
    int i;
    unsigned int sl;
    int pl;
    unsigned int pwlen;
    AP_MD5_CTX ctx, ctx1;
    unsigned long l;

    /* 
     * Refine the salt first.  It's possible we were given an already-hashed
     * string as the salt argument, so extract the actual salt value from it
     * if so.  Otherwise just use the string up to the first '$' as the salt.
     */
    sp = salt;

    /*
     * If it starts with the magic string, then skip that.
     */
    if (strncmp((char *)sp, AP_MD5PW_ID, AP_MD5PW_IDLEN) == 0) {
	sp += AP_MD5PW_IDLEN;
    }

    /*
     * It stops at the first '$' or 8 chars, whichever comes first
     */
    for (ep = sp; (*ep != '\0') && (*ep != '$') && (ep < (sp + 8)); ep++) {
	continue;
    }

    /*
     * Get the length of the true salt
     */
    sl = ep - sp;

    /*
     * 'Time to make the doughnuts..'
     */
    ap_MD5Init(&ctx);

    pwlen = strlen((char *)pw);
    /*
     * The password first, since that is what is most unknown
     */
    ap_MD5Update(&ctx, pw, pwlen);

    /*
     * Then our magic string
     */
    ap_MD5Update(&ctx, (const unsigned char *) AP_MD5PW_ID, AP_MD5PW_IDLEN);

    /*
     * Then the raw salt
     */
    ap_MD5Update(&ctx, sp, sl);

    /*
     * Then just as many characters of the MD5(pw, salt, pw)
     */
    ap_MD5Init(&ctx1);
    ap_MD5Update(&ctx1, pw, pwlen);
    ap_MD5Update(&ctx1, sp, sl);
    ap_MD5Update(&ctx1, pw, pwlen);
    ap_MD5Final(final, &ctx1);
    for(pl = pwlen; pl > 0; pl -= 16) {
	ap_MD5Update(&ctx, final, (pl > 16) ? 16 : (unsigned int) pl);
    }

    /*
     * Don't leave anything around in vm they could use.
     */
    memset(final, 0, sizeof(final));

    /*
     * Then something really weird...
     */
    for (i = pwlen; i != 0; i >>= 1) {
	if (i & 1) {
	    ap_MD5Update(&ctx, final, 1);
	}
	else {
	    ap_MD5Update(&ctx, pw, 1);
	}
    }

    /*
     * Now make the output string.  We know our limitations, so we
     * can use the string routines without bounds checking.
     */
    ap_cpystrn(passwd, AP_MD5PW_ID, AP_MD5PW_IDLEN + 1);
    ap_cpystrn(passwd + AP_MD5PW_IDLEN, (char *)sp, sl + 1);
    passwd[AP_MD5PW_IDLEN + sl]     = '$';
    passwd[AP_MD5PW_IDLEN + sl + 1] = '\0';

    ap_MD5Final(final, &ctx);

    /*
     * And now, just to make sure things don't run too fast..
     * On a 60 Mhz Pentium this takes 34 msec, so you would
     * need 30 seconds to build a 1000 entry dictionary...
     */
    for (i = 0; i < 1000; i++) {
	ap_MD5Init(&ctx1);
	if (i & 1) {
	    ap_MD5Update(&ctx1, pw, pwlen);
	}
	else {
	    ap_MD5Update(&ctx1, final, 16);
	}
	if (i % 3) {
	    ap_MD5Update(&ctx1, sp, sl);
	}

	if (i % 7) {
	    ap_MD5Update(&ctx1, pw, pwlen);
	}

	if (i & 1) {
	    ap_MD5Update(&ctx1, final, 16);
	}
	else {
	    ap_MD5Update(&ctx1, pw, pwlen);
	}
	ap_MD5Final(final,&ctx1);
    }

    p = passwd + strlen(passwd);

    l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; ap_to64(p, l, 4); p += 4;
    l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; ap_to64(p, l, 4); p += 4;
    l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; ap_to64(p, l, 4); p += 4;
    l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; ap_to64(p, l, 4); p += 4;
    l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; ap_to64(p, l, 4); p += 4;
    l =                    final[11]                ; ap_to64(p, l, 2); p += 2;
    *p = '\0';

    /*
     * Don't leave anything around in vm they could use.
     */
    memset(final, 0, sizeof(final));

    ap_cpystrn(result, passwd, nbytes - 1);
}