/*

 * Copyright 1999-2018 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

/*-

 * This is a generic 32 bit "collector" for message digest algorithms.

 * Whenever needed it collects input character stream into chunks of

 * 32 bit values and invokes a block function that performs actual hash

 * calculations.

 *

 * Porting guide.

 *

 * Obligatory macros:

 *

 * DATA_ORDER_IS_BIG_ENDIAN or DATA_ORDER_IS_LITTLE_ENDIAN

 *      this macro defines byte order of input stream.

 * HASH_CBLOCK

 *      size of a unit chunk HASH_BLOCK operates on.

 * HASH_LONG

 *      has to be at least 32 bit wide.

 * HASH_CTX

 *      context structure that at least contains following

 *      members:

 *              typedef struct {

 *                      ...

 *                      HASH_LONG       Nl,Nh;

 *                      either {

 *                      HASH_LONG       data[HASH_LBLOCK];

 *                      unsigned char   data[HASH_CBLOCK];

 *                      };

 *                      unsigned int    num;

 *                      ...

 *                      } HASH_CTX;

 *      data[] vector is expected to be zeroed upon first call to

 *      HASH_UPDATE.

 * HASH_UPDATE

 *      name of "Update" function, implemented here.

 * HASH_TRANSFORM

 *      name of "Transform" function, implemented here.

 * HASH_FINAL

 *      name of "Final" function, implemented here.

 * HASH_BLOCK_DATA_ORDER

 *      name of "block" function capable of treating *unaligned* input

 *      message in original (data) byte order, implemented externally.

 * HASH_MAKE_STRING

 *      macro converting context variables to an ASCII hash string.

 *

 * MD5 example:

 *

 *      #define DATA_ORDER_IS_LITTLE_ENDIAN

 *

 *      #define HASH_LONG               MD5_LONG

 *      #define HASH_CTX                MD5_CTX

 *      #define HASH_CBLOCK             MD5_CBLOCK

 *      #define HASH_UPDATE             MD5_Update

 *      #define HASH_TRANSFORM          MD5_Transform

 *      #define HASH_FINAL              MD5_Final

 *      #define HASH_BLOCK_DATA_ORDER   md5_block_data_order

 */

#include <openssl/crypto.h>

#if !defined(DATA_ORDER_IS_BIG_ENDIAN) && !defined(DATA_ORDER_IS_LITTLE_ENDIAN)

# error "DATA_ORDER must be defined!"

#endif

#ifndef HASH_CBLOCK

# error "HASH_CBLOCK must be defined!"

#endif

#ifndef HASH_LONG

# error "HASH_LONG must be defined!"

#endif

#ifndef HASH_CTX

# error "HASH_CTX must be defined!"

#endif

#ifndef HASH_UPDATE

# error "HASH_UPDATE must be defined!"

#endif

#ifndef HASH_TRANSFORM

# error "HASH_TRANSFORM must be defined!"

#endif

#ifndef HASH_FINAL

# error "HASH_FINAL must be defined!"

#endif

#ifndef HASH_BLOCK_DATA_ORDER

# error "HASH_BLOCK_DATA_ORDER must be defined!"

#endif

#define ROTATE(a,n)     (((a)<<(n))|(((a)&0xffffffff)>>(32-(n))))

#if defined(DATA_ORDER_IS_BIG_ENDIAN)

# define HOST_c2l(c,l)  (l =(((unsigned long)(*((c)++)))<<24),          \

                         l|=(((unsigned long)(*((c)++)))<<16),          \

                         l|=(((unsigned long)(*((c)++)))<< 8),          \

                         l|=(((unsigned long)(*((c)++)))    )           )

# define HOST_l2c(l,c)  (*((c)++)=(unsigned char)(((l)>>24)&0xff),      \

                         *((c)++)=(unsigned char)(((l)>>16)&0xff),      \

                         *((c)++)=(unsigned char)(((l)>> 8)&0xff),      \

                         *((c)++)=(unsigned char)(((l)    )&0xff),      \

                         l)

#elif defined(DATA_ORDER_IS_LITTLE_ENDIAN)

# define HOST_c2l(c,l)  (l =(((unsigned long)(*((c)++)))    ),          \

                         l|=(((unsigned long)(*((c)++)))<< 8),          \

                         l|=(((unsigned long)(*((c)++)))<<16),          \

                         l|=(((unsigned long)(*((c)++)))<<24)           )

# define HOST_l2c(l,c)  (*((c)++)=(unsigned char)(((l)    )&0xff),      \

                         *((c)++)=(unsigned char)(((l)>> 8)&0xff),      \

                         *((c)++)=(unsigned char)(((l)>>16)&0xff),      \

                         *((c)++)=(unsigned char)(((l)>>24)&0xff),      \

                         l)

#endif

/*

 * Time for some action :-)

 */

int HASH_UPDATE(HASH_CTX *c, const void *data_, size_t len)

{

    const unsigned char *data = data_;

    unsigned char *p;

    HASH_LONG l;

    size_t n;

    if (len == 0)

        return 1;

    l = (c->Nl + (((HASH_LONG) len) << 3)) & 0xffffffffUL;

    if (l < c->Nl)              /* overflow */

        c->Nh++;

    c->Nh += (HASH_LONG) (len >> 29); /* might cause compiler warning on

                                       * 16-bit */

    c->Nl = l;

    n = c->num;

    if (n != 0) {

        p = (unsigned char *)c->data;

        if (len >= HASH_CBLOCK || len + n >= HASH_CBLOCK) {

            memcpy(p + n, data, HASH_CBLOCK - n);

            HASH_BLOCK_DATA_ORDER(c, p, 1);

            n = HASH_CBLOCK - n;

            data += n;

            len -= n;

            c->num = 0;

            /*

             * We use memset rather than OPENSSL_cleanse() here deliberately.

             * Using OPENSSL_cleanse() here could be a performance issue. It

             * will get properly cleansed on finalisation so this isn't a

             * security problem.

             */

            memset(p, 0, HASH_CBLOCK); /* keep it zeroed */

        } else {

            memcpy(p + n, data, len);

            c->num += (unsigned int)len;

            return 1;

        }

    }

    n = len / HASH_CBLOCK;

    if (n > 0) {

        HASH_BLOCK_DATA_ORDER(c, data, n);

        n *= HASH_CBLOCK;

        data += n;

        len -= n;

    }

    if (len != 0) {

        p = (unsigned char *)c->data;

        c->num = (unsigned int)len;

        memcpy(p, data, len);

    }

    return 1;

}

void HASH_TRANSFORM(HASH_CTX *c, const unsigned char *data)

{

    HASH_BLOCK_DATA_ORDER(c, data, 1);

}

int HASH_FINAL(unsigned char *md, HASH_CTX *c)

{

    unsigned char *p = (unsigned char *)c->data;

    size_t n = c->num;

    p[n] = 0x80;                /* there is always room for one */

    n++;

    if (n > (HASH_CBLOCK - 8)) {

        memset(p + n, 0, HASH_CBLOCK - n);

        n = 0;

        HASH_BLOCK_DATA_ORDER(c, p, 1);

    }

    memset(p + n, 0, HASH_CBLOCK - 8 - n);

    p += HASH_CBLOCK - 8;

#if   defined(DATA_ORDER_IS_BIG_ENDIAN)

    (void)HOST_l2c(c->Nh, p);

    (void)HOST_l2c(c->Nl, p);

#elif defined(DATA_ORDER_IS_LITTLE_ENDIAN)

    (void)HOST_l2c(c->Nl, p);

    (void)HOST_l2c(c->Nh, p);

#endif

    p -= HASH_CBLOCK;

    HASH_BLOCK_DATA_ORDER(c, p, 1);

    c->num = 0;

    OPENSSL_cleanse(p, HASH_CBLOCK);

#ifndef HASH_MAKE_STRING

# error "HASH_MAKE_STRING must be defined!"

#else

    HASH_MAKE_STRING(c, md);

#endif

    return 1;

}

#ifndef MD32_REG_T

# if defined(__alpha) || defined(__sparcv9) || defined(__mips)

#  define MD32_REG_T long

/*

 * This comment was originally written for MD5, which is why it

 * discusses A-D. But it basically applies to all 32-bit digests,

 * which is why it was moved to common header file.

 *

 * In case you wonder why A-D are declared as long and not

 * as MD5_LONG. Doing so results in slight performance

 * boost on LP64 architectures. The catch is we don't

 * really care if 32 MSBs of a 64-bit register get polluted

 * with eventual overflows as we *save* only 32 LSBs in

 * *either* case. Now declaring 'em long excuses the compiler

 * from keeping 32 MSBs zeroed resulting in 13% performance

 * improvement under SPARC Solaris7/64 and 5% under AlphaLinux.

 * Well, to be honest it should say that this *prevents*

 * performance degradation.

 */

# else

/*

 * Above is not absolute and there are LP64 compilers that

 * generate better code if MD32_REG_T is defined int. The above

 * pre-processor condition reflects the circumstances under which

 * the conclusion was made and is subject to further extension.

 */

#  define MD32_REG_T int

# endif

#endif