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

    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 (apr_uint32_t) into output (unsigned char). Assumes len is
 * a multiple of 4.
 */
static void Encode(unsigned char *output, const apr_uint32_t *input,
                   unsigned int len)
{
    unsigned int i, j;
    apr_uint32_t 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 (apr_uint32_t). Assumes len is
 * a multiple of 4.
 */
static void Decode(apr_uint32_t *output, const unsigned char *input,
                   unsigned int len)
{
    unsigned int i, j;

    for (i = 0, j = 0; j < len; i++, j += 4)
        output[i] = ((apr_uint32_t)input[j])             |
                    (((apr_uint32_t)input[j + 1]) << 8)  |
                    (((apr_uint32_t)input[j + 2]) << 16) |
                    (((apr_uint32_t)input[j + 3]) << 24);
}

#if APR_CHARSET_EBCDIC
APU_DECLARE(apr_status_t) apr_MD5InitEBCDIC(apr_xlate_t *xlate)
{
    xlate_ebcdic_to_ascii = xlate;
    return APR_SUCCESS;
}
#endif

/*
 * Define the Magic String prefix that identifies a password as being
 * hashed using our algorithm.
 */
static const char *apr1_id = "$apr1$";

/*
 * 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.
 */

static void 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;
    }
}

APU_DECLARE(apr_status_t) apr_md5_encode(const char *pw, const char *salt,
                             char *result, apr_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 char *sp, *ep;
    unsigned char final[APR_MD5_DIGESTSIZE];
    apr_ssize_t sl, pl, i;
    apr_md5_ctx_t 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(sp, apr1_id, strlen(apr1_id))) {
        sp += strlen(apr1_id);
    }

    /*
     * 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..'
     */
    apr_md5_init(&ctx);
#if APR_CHARSET_EBCDIC
    apr_md5_set_xlate(&ctx, xlate_ebcdic_to_ascii);
#endif
    
    /*
     * The password first, since that is what is most unknown
     */
    apr_md5_update(&ctx, (unsigned char *)pw, strlen(pw));

    /*
     * Then our magic string
     */
    apr_md5_update(&ctx, (unsigned char *)apr1_id, strlen(apr1_id));

    /*
     * Then the raw salt
     */
    apr_md5_update(&ctx, (unsigned char *)sp, sl);

    /*
     * Then just as many characters of the MD5(pw, salt, pw)
     */
    apr_md5_init(&ctx1);
    apr_md5_update(&ctx1, (unsigned char *)pw, strlen(pw));
    apr_md5_update(&ctx1, (unsigned char *)sp, sl);
    apr_md5_update(&ctx1, (unsigned char *)pw, strlen(pw));
    apr_md5_final(final, &ctx1);
    for (pl = strlen(pw); pl > 0; pl -= APR_MD5_DIGESTSIZE) {
        apr_md5_update(&ctx, final, 
                      (pl > APR_MD5_DIGESTSIZE) ? APR_MD5_DIGESTSIZE : pl);
    }

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

    /*
     * Then something really weird...
     */
    for (i = strlen(pw); i != 0; i >>= 1) {
        if (i & 1) {
            apr_md5_update(&ctx, final, 1);
        }
        else {
            apr_md5_update(&ctx, (unsigned char *)pw, 1);
        }
    }

    /*
     * Now make the output string.  We know our limitations, so we
     * can use the string routines without bounds checking.
     */
    strcpy(passwd, apr1_id);
    strncat(passwd, sp, sl);
    strcat(passwd, "$");

    apr_md5_final(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++) {
        apr_md5_init(&ctx1);
        if (i & 1) {
            apr_md5_update(&ctx1, (unsigned char *)pw, strlen(pw));
        }
        else {
            apr_md5_update(&ctx1, final, APR_MD5_DIGESTSIZE);
        }
        if (i % 3) {
            apr_md5_update(&ctx1, (unsigned char *)sp, sl);
        }

        if (i % 7) {
            apr_md5_update(&ctx1, (unsigned char *)pw, strlen(pw));
        }

        if (i & 1) {
            apr_md5_update(&ctx1, final, APR_MD5_DIGESTSIZE);
        }
        else {
            apr_md5_update(&ctx1, (unsigned char *)pw, strlen(pw));
        }
        apr_md5_final(final,&ctx1);
    }

    p = passwd + strlen(passwd);

    l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; to64(p, l, 4); p += 4;
    l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; to64(p, l, 4); p += 4;
    l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; to64(p, l, 4); p += 4;
    l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; to64(p, l, 4); p += 4;
    l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; to64(p, l, 4); p += 4;
    l =                    final[11]                ; to64(p, l, 2); p += 2;
    *p = '\0';

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

    apr_cpystrn(result, passwd, nbytes - 1);
    return APR_SUCCESS;
}

#if !defined(WIN32) && !defined(BEOS) && !defined(NETWARE)
#if defined(APU_CRYPT_THREADSAFE) || !APR_HAS_THREADS || \
    defined(CRYPT_R_CRYPTD) || defined(CRYPT_R_STRUCT_CRYPT_DATA)

#define crypt_mutex_lock()
#define crypt_mutex_unlock()

#elif APR_HAVE_PTHREAD_H && defined(PTHREAD_MUTEX_INITIALIZER)

static pthread_mutex_t crypt_mutex = PTHREAD_MUTEX_INITIALIZER;
static void crypt_mutex_lock(void)
{
    pthread_mutex_lock(&crypt_mutex);
}

static void crypt_mutex_unlock(void)
{
    pthread_mutex_unlock(&crypt_mutex);
}

#else

#error apr_password_validate() is not threadsafe.  rebuild APR without thread support.

#endif
#endif

/*
 * Validate a plaintext password against a smashed one.  Use either
 * crypt() (if available) or apr_md5_encode(), depending upon the format
 * of the smashed input password.  Return APR_SUCCESS if they match, or
 * APR_EMISMATCH if they don't.
 */

APU_DECLARE(apr_status_t) apr_password_validate(const char *passwd, 
                                                const char *hash)
{
    char sample[120];
#if !defined(WIN32) && !defined(BEOS) && !defined(NETWARE)
    char *crypt_pw;
#endif
    if (!strncmp(hash, apr1_id, strlen(apr1_id))) {
        /*
         * The hash was created using our custom algorithm.
         */
        apr_md5_encode(passwd, hash, sample, sizeof(sample));
    }
    else if (!strncmp(hash, APR_SHA1PW_ID, APR_SHA1PW_IDLEN)) {
        apr_sha1_base64(passwd, strlen(passwd), sample);
    }
    else {
        /*
         * It's not our algorithm, so feed it to crypt() if possible.
         */
#if defined(WIN32) || defined(BEOS) || defined(NETWARE)
        apr_cpystrn(sample, passwd, sizeof(sample) - 1);
#elif defined(CRYPT_R_CRYPTD)
        CRYPTD buffer;

        crypt_pw = crypt_r(passwd, hash, &buffer);
        apr_cpystrn(sample, crypt_pw, sizeof(sample) - 1);
#elif defined(CRYPT_R_STRUCT_CRYPT_DATA)
        struct crypt_data buffer;

        /* having to clear this seems bogus... GNU doc is
         * confusing...  user report found from google says
         * the crypt_data struct had to be cleared to get
         * the same result as plain crypt()
         */
        memset(&buffer, 0, sizeof(buffer));
        crypt_pw = crypt_r(passwd, hash, &buffer);
        apr_cpystrn(sample, crypt_pw, sizeof(sample) - 1);
#else
        /* Do a bit of sanity checking since we know that crypt_r()
         * should always be used for threaded builds on AIX, and
         * problems in configure logic can result in the wrong
         * choice being made.
         */
#if defined(_AIX) && APR_HAS_THREADS
#error Configuration error!  crypt_r() should have been selected!
#endif

        /* Handle thread safety issues by holding a mutex around the
         * call to crypt().
         */
        crypt_mutex_lock();
        crypt_pw = crypt(passwd, hash);
        apr_cpystrn(sample, crypt_pw, sizeof(sample) - 1);
        crypt_mutex_unlock();
#endif
    }
    return (strcmp(sample, hash) == 0) ? APR_SUCCESS : APR_EMISMATCH;
}