/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 */


/*! \file
 * 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.
 */

#include "config.h"

#include <pk11/site.h>

#ifndef PK11_MD5_DISABLE

#include <stdbool.h>

#include <isc/assertions.h>
#include <isc/md5.h>
#include <isc/platform.h>
#include <isc/safe.h>
#include <isc/string.h>
#include <isc/types.h>

#if PKCS11CRYPTO
#include <pk11/internal.h>
#include <pk11/pk11.h>
#endif

#include <isc/util.h>

#ifdef ISC_PLATFORM_OPENSSLHASH
#if OPENSSL_VERSION_NUMBER < 0x10100000L || defined(LIBRESSL_VERSION_NUMBER)
#define EVP_MD_CTX_new() &(ctx->_ctx)
#define EVP_MD_CTX_free(ptr) EVP_MD_CTX_cleanup(ptr)
#endif

void
isc_md5_init(isc_md5_t *ctx) {
	ctx->ctx = EVP_MD_CTX_new();
	RUNTIME_CHECK(ctx->ctx != NULL);
	if (EVP_DigestInit(ctx->ctx, EVP_md5()) != 1) {
		FATAL_ERROR(__FILE__, __LINE__, "Cannot initialize MD5.");
	}
}

void
isc_md5_invalidate(isc_md5_t *ctx) {
	EVP_MD_CTX_free(ctx->ctx);
	ctx->ctx = NULL;
}

void
isc_md5_update(isc_md5_t *ctx, const unsigned char *buf, unsigned int len) {
	if (len == 0U)
		return;
	RUNTIME_CHECK(EVP_DigestUpdate(ctx->ctx,
				       (const void *) buf,
				       (size_t) len) == 1);
}

void
isc_md5_final(isc_md5_t *ctx, unsigned char *digest) {
	RUNTIME_CHECK(EVP_DigestFinal(ctx->ctx, digest, NULL) == 1);
	EVP_MD_CTX_free(ctx->ctx);
	ctx->ctx = NULL;
}

#elif PKCS11CRYPTO

void
isc_md5_init(isc_md5_t *ctx) {
	CK_RV rv;
	CK_MECHANISM mech = { CKM_MD5, NULL, 0 };

	RUNTIME_CHECK(pk11_get_session(ctx, OP_DIGEST, true, false,
				       false, NULL, 0) == ISC_R_SUCCESS);
	PK11_FATALCHECK(pkcs_C_DigestInit, (ctx->session, &mech));
}

void
isc_md5_invalidate(isc_md5_t *ctx) {
	CK_BYTE garbage[ISC_MD5_DIGESTLENGTH];
	CK_ULONG len = ISC_MD5_DIGESTLENGTH;

	if (ctx->handle == NULL)
		return;
	(void) pkcs_C_DigestFinal(ctx->session, garbage, &len);
	isc_safe_memwipe(garbage, sizeof(garbage));
	pk11_return_session(ctx);
}

void
isc_md5_update(isc_md5_t *ctx, const unsigned char *buf, unsigned int len) {
	CK_RV rv;
	CK_BYTE_PTR pPart;

	DE_CONST(buf, pPart);
	PK11_FATALCHECK(pkcs_C_DigestUpdate,
			(ctx->session, pPart, (CK_ULONG) len));
}

void
isc_md5_final(isc_md5_t *ctx, unsigned char *digest) {
	CK_RV rv;
	CK_ULONG len = ISC_MD5_DIGESTLENGTH;

	PK11_FATALCHECK(pkcs_C_DigestFinal,
			(ctx->session, (CK_BYTE_PTR) digest, &len));
	pk11_return_session(ctx);
}

#else

static void
byteSwap(uint32_t *buf, unsigned words)
{
	unsigned char *p = (unsigned char *)buf;

	do {
		*buf++ = (uint32_t)((unsigned)p[3] << 8 | p[2]) << 16 |
			((unsigned)p[1] << 8 | p[0]);
		p += 4;
	} while (--words);
}

/*!
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
void
isc_md5_init(isc_md5_t *ctx) {
	ctx->buf[0] = 0x67452301;
	ctx->buf[1] = 0xefcdab89;
	ctx->buf[2] = 0x98badcfe;
	ctx->buf[3] = 0x10325476;

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

void
isc_md5_invalidate(isc_md5_t *ctx) {
	isc_safe_memwipe(ctx, 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,in,s) \
	 (w += f(x,y,z) + in, w = (w<<s | w>>(32-s)) + 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.
 */
static void
transform(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;
}

/*!
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
void
isc_md5_update(isc_md5_t *ctx, const unsigned char *buf, unsigned int len) {
	uint32_t t;

	/* Update byte count */

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

	t = 64 - (t & 0x3f);	/* Space available in ctx->in (at least 1) */
	if (t > len) {
		memmove((unsigned char *)ctx->in + 64 - t, buf, len);
		return;
	}
	/* First chunk is an odd size */
	memmove((unsigned char *)ctx->in + 64 - t, buf, t);
	byteSwap(ctx->in, 16);
	transform(ctx->buf, ctx->in);
	buf += t;
	len -= t;

	/* Process data in 64-byte chunks */
	while (len >= 64) {
		memmove(ctx->in, buf, 64);
		byteSwap(ctx->in, 16);
		transform(ctx->buf, ctx->in);
		buf += 64;
		len -= 64;
	}

	/* Handle any remaining bytes of data. */
	memmove(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
isc_md5_final(isc_md5_t *ctx, unsigned char *digest) {
	int count = ctx->bytes[0] & 0x3f;    /* Number of bytes in ctx->in */
	unsigned char *p = (unsigned char *)ctx->in + count;

	/* Set the first char of padding to 0x80.  There is always room. */
	*p++ = 0x80;

	/* Bytes of padding needed to make 56 bytes (-8..55) */
	count = 56 - 1 - count;

	if (count < 0) {	/* Padding forces an extra block */
		memset(p, 0, count + 8);
		byteSwap(ctx->in, 16);
		transform(ctx->buf, ctx->in);
		p = (unsigned char *)ctx->in;
		count = 56;
	}
	memset(p, 0, count);
	byteSwap(ctx->in, 14);

	/* Append length in bits and transform */
	ctx->in[14] = ctx->bytes[0] << 3;
	ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
	transform(ctx->buf, ctx->in);

	byteSwap(ctx->buf, 4);
	memmove(digest, ctx->buf, 16);
	isc_safe_memwipe(ctx, sizeof(*ctx));	/* In case it's sensitive */
}
#endif

/*
 * Check for MD5 support; if it does not work, raise a fatal error.
 *
 * Use "a" as the test vector.
 *
 * Standard use is testing false and result true.
 * Testing use is testing true and result false;
 */
bool
isc_md5_check(bool testing) {
	isc_md5_t ctx;
	unsigned char input = 'a';
	unsigned char digest[ISC_MD5_DIGESTLENGTH];
	unsigned char expected[] = {
		0x0c, 0xc1, 0x75, 0xb9, 0xc0, 0xf1, 0xb6, 0xa8,
		0x31, 0xc3, 0x99, 0xe2, 0x69, 0x77, 0x26, 0x61
	};

	INSIST(sizeof(expected) == ISC_MD5_DIGESTLENGTH);

	/*
	 * Introduce a fault for testing.
	 */
	if (testing) {
		input ^= 0x01;
	}

	/*
	 * These functions do not return anything; any failure will be fatal.
	 */
	isc_md5_init(&ctx);
	isc_md5_update(&ctx, &input, 1U);
	isc_md5_final(&ctx, digest);

	/*
	 * Must return true in standard case, should return false for testing.
	 */
	return (memcmp(digest, expected, ISC_MD5_DIGESTLENGTH) == 0);
}

#else /* !PK11_MD5_DISABLE */
#ifdef WIN32
/* Make the Visual Studio linker happy */
#include <isc/util.h>

void isc_md5_final() { INSIST(0); }
void isc_md5_init() { INSIST(0); }
void isc_md5_invalidate() { INSIST(0); }
void isc_md5_update() { INSIST(0); }
void isc_md5_check() { INSIST(0); }
#endif
#endif /* PK11_MD5_DISABLE */