/** @file
	taken from libmd, added pa_ prefixes, Parser 3 includes,
	Copyright (c) 2001-2026 Art. Lebedev Studio (https://www.artlebedev.com)
*/

/*	$OpenBSD: md5.c,v 1.7 2004/05/28 15:10:27 millert Exp $	*/

/*
 * 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
 * MD5Context structure, pass it to MD5Init, call MD5Update as
 * needed on buffers full of bytes, and then call MD5Final, which
 * will fill a supplied 16-byte array with the digest.
 */

/*
 * The pa_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 "pa_md5.h"

volatile const char * IDENT_PA_MD5_C="$Id: pa_md5c.c,v 1.25 2026/04/25 13:38:46 moko Exp $" IDENT_PA_MD5_H;

#define PUT_64BIT_LE(cp, value) do {					\
	(cp)[7] = (uint8_t)((value) >> 56);				\
	(cp)[6] = (uint8_t)((value) >> 48);				\
	(cp)[5] = (uint8_t)((value) >> 40);				\
	(cp)[4] = (uint8_t)((value) >> 32);				\
	(cp)[3] = (uint8_t)((value) >> 24);				\
	(cp)[2] = (uint8_t)((value) >> 16);				\
	(cp)[1] = (uint8_t)((value) >> 8);				\
	(cp)[0] = (uint8_t)(value); } while (0)

#define PUT_32BIT_LE(cp, value) do {					\
	(cp)[3] = (unsigned char)((value) >> 24);			\
	(cp)[2] = (unsigned char)((value) >> 16);			\
	(cp)[1] = (unsigned char)((value) >> 8);			\
	(cp)[0] = (unsigned char)(value); } while (0)

static uint8_t PADDING[MD5_BLOCK_LENGTH] = {
	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
};

/*
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
void pa_MD5Init(PA_MD5_CTX *ctx)
{
	ctx->count = 0;
	ctx->state[0] = 0x67452301;
	ctx->state[1] = 0xefcdab89;
	ctx->state[2] = 0x98badcfe;
	ctx->state[3] = 0x10325476;
}

/*
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
void pa_MD5Update(PA_MD5_CTX *ctx, const unsigned char *input, size_t len)
{
	size_t have, need;

	/* Check how many bytes we already have and how many more we need. */
	have = (size_t)((ctx->count >> 3) & (MD5_BLOCK_LENGTH - 1));
	need = MD5_BLOCK_LENGTH - have;

	/* Update bitcount */
	ctx->count += (uint64_t)len << 3;

	if (len >= need) {
		if (have != 0) {
			memcpy(ctx->buffer + have, input, need);
			pa_MD5Transform(ctx->state, ctx->buffer);
			input += need;
			len -= need;
			have = 0;
		}

		/* Process data in MD5_BLOCK_LENGTH-byte chunks. */
		while (len >= MD5_BLOCK_LENGTH) {
			pa_MD5Transform(ctx->state, input);
			input += MD5_BLOCK_LENGTH;
			len -= MD5_BLOCK_LENGTH;
		}
	}

	/* Handle any remaining bytes of data. */
	if (len != 0)
		memcpy(ctx->buffer + have, input, len);
}

/*
 * Pad pad to 64-byte boundary with the bit pattern
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
void pa_MD5Pad(PA_MD5_CTX *ctx)
{
	uint8_t count[8];
	size_t padlen;

	/* Convert count to 8 bytes in little endian order. */
	PUT_64BIT_LE(count, ctx->count);

	/* Pad out to 56 mod 64. */
	padlen = MD5_BLOCK_LENGTH -
	    ((ctx->count >> 3) & (MD5_BLOCK_LENGTH - 1));
	if (padlen < 1 + 8)
		padlen += MD5_BLOCK_LENGTH;
	pa_MD5Update(ctx, PADDING, padlen - 8);		/* padlen - 8 <= 64 */
	pa_MD5Update(ctx, count, 8);
}

/*
 * Final wrapup--call MD5Pad, fill in digest and zero out ctx.
 */
void pa_MD5Final(unsigned char digest[MD5_DIGEST_LENGTH], PA_MD5_CTX *ctx)
{
	int i;

	pa_MD5Pad(ctx);
	if (digest != NULL) {
		for (i = 0; i < 4; i++)
			PUT_32BIT_LE(digest + i * 4, ctx->state[i]);
		memset(ctx, 0, sizeof(*ctx));
	}
}


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

/*
 * 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 pa_MD5Transform(uint32_t state[4], const uint8_t block[MD5_BLOCK_LENGTH])
{
	uint32_t a, b, c, d, in[MD5_BLOCK_LENGTH / 4];

#ifndef WORDS_BIGENDIAN
	memcpy(in, block, sizeof(in));
#else
	for (a = 0; a < MD5_BLOCK_LENGTH / 4; a++) {
		in[a] = (uint32_t)(
		    (uint32_t)(block[a * 4 + 0]) |
		    (uint32_t)(block[a * 4 + 1]) <<  8 |
		    (uint32_t)(block[a * 4 + 2]) << 16 |
		    (uint32_t)(block[a * 4 + 3]) << 24);
	}
#endif

	a = state[0];
	b = state[1];
	c = state[2];
	d = state[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);

	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;
}

/*
 * 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 pa_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 pa_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;
    PA_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, PA_MD5PW_ID, PA_MD5PW_IDLEN) == 0) {
	sp += PA_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..'
     */
    pa_MD5Init(&ctx);

    pwlen = strlen((char *)pw);
    /*
     * The password first, since that is what is most unknown
     */
    pa_MD5Update(&ctx, pw, pwlen);

    /*
     * Then our magic string
     */
    pa_MD5Update(&ctx, (const unsigned char *) PA_MD5PW_ID, PA_MD5PW_IDLEN);

    /*
     * Then the raw salt
     */
    pa_MD5Update(&ctx, sp, sl);

    /*
     * Then just as many characters of the MD5(pw, salt, pw)
     */
    pa_MD5Init(&ctx1);
    pa_MD5Update(&ctx1, pw, pwlen);
    pa_MD5Update(&ctx1, sp, sl);
    pa_MD5Update(&ctx1, pw, pwlen);
    pa_MD5Final(final, &ctx1);
    for(pl = pwlen; pl > 0; pl -= 16) {
	pa_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) {
	    pa_MD5Update(&ctx, final, 1);
	}
	else {
	    pa_MD5Update(&ctx, pw, 1);
	}
    }

    /*
     * Now make the output string.  We know our limitations, so we
     * can use the string routines without bounds checking.
     */
    strncpy(passwd, PA_MD5PW_ID, PA_MD5PW_IDLEN + 1);
    strncpy(passwd + PA_MD5PW_IDLEN, (char *)sp, sl + 1);
    passwd[PA_MD5PW_IDLEN + sl]     = '$';
    passwd[PA_MD5PW_IDLEN + sl + 1] = '\0';

    pa_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++) {
	pa_MD5Init(&ctx1);
	if (i & 1) {
	    pa_MD5Update(&ctx1, pw, pwlen);
	}
	else {
	    pa_MD5Update(&ctx1, final, 16);
	}
	if (i % 3) {
	    pa_MD5Update(&ctx1, sp, sl);
	}

	if (i % 7) {
	    pa_MD5Update(&ctx1, pw, pwlen);
	}

	if (i & 1) {
	    pa_MD5Update(&ctx1, final, 16);
	}
	else {
	    pa_MD5Update(&ctx1, pw, pwlen);
	}
	pa_MD5Final(final,&ctx1);
    }

    p = passwd + strlen(passwd);

    l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; pa_to64(p, l, 4); p += 4;
    l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; pa_to64(p, l, 4); p += 4;
    l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; pa_to64(p, l, 4); p += 4;
    l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; pa_to64(p, l, 4); p += 4;
    l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; pa_to64(p, l, 4); p += 4;
    l =                    final[11]                ; pa_to64(p, l, 2); p += 2;
    *p = '\0';

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

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