#ifdef WIN32
#include <process.h>
#include <windows.h>
#else
#include <sys/time.h>
#include <unistd.h>
#endif

#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "stg/ag_md5.h"

#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))

#define MD5STEP(f, w, x, y, z, data, s) \
    ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )

int i64c(int i)
{
    if (i <= 0)
        return ('.');

    if (i == 1)
        return ('/');

    if (i >= 2 && i < 12)
        return ('0' - 2 + i);

    if (i >= 12 && i < 38)
        return ('A' - 12 + i);

    if (i >= 38 && i < 63)
        return ('a' - 38 + i);

    return ('z');
}

char * l64a_(long l)
{
    static  char    buf[8];
    int i = 0;

    if (l < 0L)
        return ((char *) 0);

    do {
        buf[i++] = i64c ((int) (l % 64));
        buf[i] = '\0';
    } while (l /= 64L, l > 0 && i < 6);

    return (buf);
}

char * crypt_make_salt(void)
{

    static char result[40];
    #ifdef WIN32
    unsigned int tsec;
    #else
    struct timeval tv;
    #endif

    result[0] = '\0';
        strcpy(result, "$1$");  /* magic for the new MD5 crypt() */

    /*
     * Generate 8 chars of salt, the old crypt() will use only first 2.
     */
    #ifdef WIN32
    strcat(result, l64a_(GetTickCount()));
    tsec = time(NULL);
    strcat(result, l64a_(tsec + getpid() + clock()));
    #else
    gettimeofday(&tv, (struct timezone *) 0);
    strcat(result, l64a_(tv.tv_usec));
    strcat(result, l64a_(tv.tv_sec + getpid() + clock()));
    #endif

    if (strlen(result) > 3 + 8)  /* magic+salt */
        result[11] = '\0';

    return result;
}

void byteReverse(unsigned char *buf, unsigned longs)
{
    uint32_t t;
    do {
    t = (uint32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
        ((unsigned) buf[1] << 8 | buf[0]);
    *(uint32_t *) buf = t;
    buf += 4;
    } while (--longs);
}

/*
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
void MD5Init(struct MD5Context *ctx)
{
    ctx->buf[0] = 0x67452301;
    ctx->buf[1] = 0xefcdab89;
    ctx->buf[2] = 0x98badcfe;
    ctx->buf[3] = 0x10325476;

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

/*
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
void MD5Update(struct MD5Context *ctx, char const *buf, unsigned len)
{
    uint32_t t;

    /* Update bitcount */

    t = ctx->bits[0];
    if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t)
    ctx->bits[1]++;     /* Carry from low to high */
    ctx->bits[1] += len >> 29;

    t = (t >> 3) & 0x3f;    /* Bytes already in shsInfo->data */

    /* Handle any leading odd-sized chunks */

    if (t) {
    unsigned char *p = (unsigned char *) ctx->in + t;

    t = 64 - t;
    if (len < t) {
        memcpy(p, buf, len);
        return;
    }
    memcpy(p, buf, t);
    byteReverse(ctx->in, 16);
    MD5Transform(ctx->buf, (uint32_t *) ctx->in);
    buf += t;
    len -= t;
    }
    /* Process data in 64-byte chunks */

    while (len >= 64) {
    memcpy(ctx->in, buf, 64);
    byteReverse(ctx->in, 16);
    MD5Transform(ctx->buf, (uint32_t *) ctx->in);
    buf += 64;
    len -= 64;
    }

    /* Handle any remaining bytes of data. */

    memcpy(ctx->in, buf, len);
}

/*
 * Final wrapup - pad to 64-byte boundary with the bit pattern
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
void
MD5Final(unsigned char digest[16], struct MD5Context *ctx)
{
    unsigned count;
    unsigned char *p;

    /* Compute number of bytes mod 64 */
    count = (ctx->bits[0] >> 3) & 0x3F;

    /* Set the first char of padding to 0x80.  This is safe since there is
       always at least one byte free */
    p = ctx->in + count;
    *p++ = 0x80;

    /* Bytes of padding needed to make 64 bytes */
    count = 64 - 1 - count;

    /* Pad out to 56 mod 64 */
    if (count < 8) {
    /* Two lots of padding:  Pad the first block to 64 bytes */
    memset(p, 0, count);
    byteReverse(ctx->in, 16);
    MD5Transform(ctx->buf, (uint32_t *) ctx->in);

    /* Now fill the next block with 56 bytes */
    memset(ctx->in, 0, 56);
    } else {
    /* Pad block to 56 bytes */
    memset(p, 0, count - 8);
    }
    byteReverse(ctx->in, 14);

    /* Append length in bits and transform */
    ((uint32_t *) ctx->in)[14] = ctx->bits[0];
    ((uint32_t *) ctx->in)[15] = ctx->bits[1];

    MD5Transform(ctx->buf, (uint32_t *) ctx->in);
    byteReverse((unsigned char *) ctx->buf, 4);
    memcpy(digest, ctx->buf, 16);
    memset((char *) ctx, 0, sizeof(ctx));   /* In case it's sensitive */
}

/*
 * The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data.  MD5Update blocks
 * the data and converts bytes into longwords for this routine.
 */
void
MD5Transform(uint32_t buf[4], uint32_t const in[16])
{
    register uint32_t 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 unsigned char itoa64[] =     /* 0 ... 63 => ascii - 64 */
    "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

static void
to64(char *s, unsigned long v, int n)
{
    while (--n >= 0) {
        *s++ = itoa64[v&0x3f];
        v >>= 6;
    }
}

/*
 * UNIX password
 *
 * Use MD5 for what it is best at...
 */

char *
libshadow_md5_crypt(const char *pw, const char *salt)
{
    static const char *magic = "$1$"; /*
                         * This string is magic for
                         * this algorithm.  Having
                         * it this way, we can get
                         * get better later on
                         */
    static char     passwd[120], *p;
    static const char *sp,*ep;
    unsigned char   final[16];
    int sl,pl,i,j;
    MD5_CTX ctx,ctx1;
    unsigned long l;

    /* Refine the Salt first */
    sp = salt;

    /* If it starts with the magic string, then skip that */
    if(!strncmp(sp,magic,strlen(magic)))
        sp += strlen(magic);

    /* It stops at the first '$', max 8 chars */
    for(ep=sp;*ep && *ep != '$' && ep < (sp+8);ep++)
        continue;

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

    MD5Init(&ctx);

    /* The password first, since that is what is most unknown */
    MD5Update(&ctx, pw, strlen(pw));

    /* Then our magic string */
    MD5Update(&ctx, magic, strlen(magic));

    /* Then the raw salt */
    MD5Update(&ctx, sp, sl);

    /* Then just as many characters of the MD5(pw,salt,pw) */
    MD5Init(&ctx1);
    MD5Update(&ctx1,pw,strlen(pw));
    MD5Update(&ctx1,sp,sl);
    MD5Update(&ctx1,pw,strlen(pw));
    MD5Final(final,&ctx1);
    for(pl = strlen(pw); pl > 0; pl -= 16)
        MD5Update(&ctx, (char*)final, pl>16 ? 16 : pl);

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

    /* Then something really weird... */
    for (j=0,i = strlen(pw); i ; i >>= 1)
        if(i&1)
            MD5Update(&ctx, (char*)final+j, 1);
        else
            MD5Update(&ctx, pw+j, 1);

    /* Now make the output string */
    strcpy(passwd,magic);
    strncat(passwd,sp,sl);
    strcat(passwd,"$");

    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++) {
        MD5Init(&ctx1);
        if(i & 1)
            MD5Update(&ctx1,pw,strlen(pw));
        else
            MD5Update(&ctx1,final,16);

        if(i % 3)
            MD5Update(&ctx1,sp,sl);

        if(i % 7)
            MD5Update(&ctx1,pw,strlen(pw));

        if(i & 1)
            MD5Update(&ctx1,final,16);
        else
            MD5Update(&ctx1,pw,strlen(pw));
        MD5Final(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);

    return passwd;
}

char *pw_encrypt(const char *clear, const char *salt) {

    /*
     * If the salt string from the password file or from crypt_make_salt()
     * begins with the magic string, use the new algorithm.
     */
    if (strncmp(salt, "$1$", 3) == 0)
            return(libshadow_md5_crypt(clear, salt));
        else return(NULL);

}
/* AG MD5 functions */
char *make_ag_hash(time_t salt, const char *clear) {
    char salt_str[20];
    char *res=NULL;
    char *p;

    unsigned long slt = salt;
    sprintf(salt_str, "$1$%08lx", slt);
    res=libshadow_md5_crypt(clear, salt_str);
    p=strrchr(res, '$');
    return(++p);
}

int check_ag_hash(time_t salt, const char *clear, const char *hash) {
    return(strcmp(hash, make_ag_hash(salt, clear)));
}