apr_md5.c

一套很值得分析的短信SMS开发源代码。是我今年早些时候从taobao上买来的。但我现在也没看完（先说清楚

/*
 * This is work is derived from material Copyright RSA Data Security, Inc.
 *
 * The RSA copyright statement and Licence for that original material is
 * included below. This is followed by the Apache copyright statement and
 * licence for the modifications made to that material.
 */

/* 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.
 */

/* Copyright 2000-2005 The Apache Software Foundation or its licensors, as
 * applicable.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * The apr_md5_encode() routine uses much code obtained from the FreeBSD 3.0
 * MD5 crypt() function, which is licenced as follows:
 * ----------------------------------------------------------------------------
 * "THE BEER-WARE LICENSE" (Revision 42):
 * <[e-mail]> 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 "apr_strings.h"
#include "apr_md5.h"
#include "apr_sha1.h" /* needed by apr_password_validate */
#include "apr_lib.h"
#include "apu_config.h"

#if APR_HAVE_STRING_H
#include <string.h>
#endif
#if APR_HAVE_CRYPT_H
#include <crypt.h>
#endif
#if APR_HAVE_UNISTD_H
#include <unistd.h>
#endif
#if APR_HAVE_PTHREAD_H
#include <pthread.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(apr_uint32_t state[4], const unsigned char block[64]);
static void Encode(unsigned char *output, const apr_uint32_t *input,
                   unsigned int len);
static void Decode(apr_uint32_t *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
};

#if APR_CHARSET_EBCDIC
static apr_xlate_t *xlate_ebcdic_to_ascii; /* used in apr_md5_encode() */
#endif

/* 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) + (apr_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) + (apr_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) + (apr_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) + (apr_uint32_t)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }

/* MD5 initialization. Begins an MD5 operation, writing a new context.
 */
APU_DECLARE(apr_status_t) apr_md5_init(apr_md5_ctx_t *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;
    context->xlate = NULL;
    
    return APR_SUCCESS;
}

/* MD5 translation setup.  Provides the APR translation handle
 * to be used for translating the content before calculating the
 * digest.
 */
APU_DECLARE(apr_status_t) apr_md5_set_xlate(apr_md5_ctx_t *context, 
                                            apr_xlate_t *xlate)
{
#if APR_HAS_XLATE
    apr_status_t rv;
    int is_sb;

    /* TODO: remove the single-byte-only restriction from this code
     */
    rv = apr_xlate_sb_get(xlate, &is_sb);
    if (rv != APR_SUCCESS) {
        return rv;
    }
    if (!is_sb) {
        return APR_EINVAL;
    }
    context->xlate = xlate;
    return APR_SUCCESS;
#else
    return APR_ENOTIMPL;
#endif /* APR_HAS_XLATE */
}

/* MD5 block update operation. Continues an MD5 message-digest
 * operation, processing another message block, and updating the
 * context.
 */
APU_DECLARE(apr_status_t) apr_md5_update(apr_md5_ctx_t *context,
                                         const void *_input,
                                         apr_size_t inputLen)
{
    const unsigned char *input = _input;
    unsigned int i, idx, partLen;
#if APR_HAS_XLATE
    apr_size_t inbytes_left, outbytes_left;
#endif

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

    /* Update number of bits */
    if ((context->count[0] += ((apr_uint32_t)inputLen << 3)) 
            < ((apr_uint32_t)inputLen << 3))
        context->count[1]++;
    context->count[1] += (apr_uint32_t)inputLen >> 29;

    partLen = 64 - idx;

    /* Transform as many times as possible. */
#if !APR_HAS_XLATE
    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 /*APR_HAS_XLATE*/
    if (inputLen >= partLen) {
        if (context->xlate) {
            inbytes_left = outbytes_left = partLen;
            apr_xlate_conv_buffer(context->xlate, (const char *)input, 
                                  &inbytes_left,
                                  (char *)&context->buffer[idx], 
                                  &outbytes_left);
        }
        else {
            memcpy(&context->buffer[idx], input, partLen);
        }
        MD5Transform(context->state, context->buffer);

        for (i = partLen; i + 63 < inputLen; i += 64) {
            if (context->xlate) {
                unsigned char inp_tmp[64];
                inbytes_left = outbytes_left = 64;
                apr_xlate_conv_buffer(context->xlate, (const char *)&input[i], 
                                      &inbytes_left, (char *)inp_tmp, 
                                      &outbytes_left);
                MD5Transform(context->state, inp_tmp);
            }
            else {
                MD5Transform(context->state, &input[i]);
            }
        }

        idx = 0;
    }
    else
        i = 0;

    /* Buffer remaining input */
    if (context->xlate) {
        inbytes_left = outbytes_left = inputLen - i;
        apr_xlate_conv_buffer(context->xlate, (const char *)&input[i], 
                              &inbytes_left, (char *)&context->buffer[idx], 
                              &outbytes_left);
    }
    else {
        memcpy(&context->buffer[idx], &input[i], inputLen - i);
    }
#endif /*APR_HAS_XLATE*/
    return APR_SUCCESS;
}

/* MD5 finalization. Ends an MD5 message-digest operation, writing the
 * the message digest and zeroizing the context.
 */
APU_DECLARE(apr_status_t) apr_md5_final(unsigned char digest[APR_MD5_DIGESTSIZE],
                                        apr_md5_ctx_t *context)
{
    unsigned char bits[8];
    unsigned int idx, padLen;

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

#if APR_HAS_XLATE
    /* apr_md5_update() should not translate for this final round. */
    context->xlate = NULL;
#endif /*APR_HAS_XLATE*/

    /* Pad out to 56 mod 64. */
    idx = (unsigned int)((context->count[0] >> 3) & 0x3f);
    padLen = (idx < 56) ? (56 - idx) : (120 - idx);
    apr_md5_update(context, PADDING, padLen);

    /* Append length (before padding) */
    apr_md5_update(context, bits, 8);

    /* Store state in digest */
    Encode(digest, context->state, APR_MD5_DIGESTSIZE);

    /* Zeroize sensitive information. */
    memset(context, 0, sizeof(*context));
    
    return APR_SUCCESS;
}

/* MD5 in one step (init, update, final)
 */
APU_DECLARE(apr_status_t) apr_md5(unsigned char digest[APR_MD5_DIGESTSIZE],
                                  const void *_input,
                                  apr_size_t inputLen)
{
    const unsigned char *input = _input;
    apr_md5_ctx_t ctx;
    apr_status_t rv;

    apr_md5_init(&ctx);

    if ((rv = apr_md5_update(&ctx, input, inputLen)) != APR_SUCCESS)
        return rv;

    return apr_md5_final(digest, &ctx);
}

/* MD5 basic transformation. Transforms state based on block. */
static void MD5Transform(apr_uint32_t state[4], const unsigned char block[64])
{
    apr_uint32_t a = state[0], b = state[1], c = state[2], d = state[3],
                 x[APR_MD5_DIGESTSIZE];

    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 */