md4.c

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/*
 * Copyright (C) 2017 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */
 
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
FILE_SECBOOT ( PERMITTED );
 
/** @file
 *
 * MD4 algorithm
 *
 */
 
#include <stdint.h>
#include <assert.h>
#include <ipxe/rotate.h>
#include <ipxe/crypto.h>
#include <ipxe/md4.h>
 
/** MD4 variables */
struct md4_variables {
        /* This layout matches that of struct md4_digest_data */
        uint32_t a;
        uint32_t b;
        uint32_t c;
        uint32_t d;
        uint32_t w[16];
} __attribute__ (( packed ));
 
/** MD4 shift amounts */
static const uint8_t r[3][4] = {
        {  3,  7, 11, 19 },
        {  3,  5,  9, 13 },
        {  3,  9, 11, 15 },
};
 
/**
 * f(b,c,d,w) for steps 0 to 15
 *
 * @v v         MD4 variables
 * @v i         Index within round
 * @ret f       f(b,c,d,w)
 */
static uint32_t md4_f_0_15 ( struct md4_variables *v, unsigned int i ) {
        return ( ( ( v->b & v->c ) | ( ~v->b & v->d ) ) + v->w[i] );
}
 
/**
 * f(b,c,d,w) for steps 16 to 31
 *
 * @v v         MD4 variables
 * @v i         Index within round
 * @ret f       f(b,c,d,w)
 */
static uint32_t md4_f_16_31 ( struct md4_variables *v, unsigned int i ) {
        return ( ( ( v->b & v->c ) | ( v->b & v->d ) | ( v->c & v->d ) ) +
                 v->w[ ( ( i << 2 ) | ( i >> 2 ) ) % 16 ] );
}
 
/**
 * f(b,c,d,w) for steps 32 to 47
 *
 * @v v         MD4 variables
 * @v i         Index within round
 * @ret f       f(b,c,d,w)
 */
static uint32_t md4_f_32_47 ( struct md4_variables *v, unsigned int i ) {
        static const uint8_t reverse[16] = {
                0, 8, 4, 12, 2, 10, 6, 14, 1, 9, 5, 13, 3, 11, 7, 15
        };
        return ( ( v->b ^ v->c ^ v->d ) + v->w[reverse[i]] );
}
 
/** An MD4 step function */
struct md4_step {
        /**
         * Calculate f(b,c,d,w)
         *
         * @v v         MD4 variables
         * @v i         Index within round
         * @ret f       f(b,c,d,w)
         */
        uint32_t ( * f ) ( struct md4_variables *v, unsigned int i );
        /** Constant */
        uint32_t constant;
};
 
/** MD4 steps */
static const struct md4_step md4_steps[4] = {
        /** 0 to 15 */
        { .f = md4_f_0_15,      .constant = 0x00000000UL },
        /** 16 to 31 */
        { .f = md4_f_16_31,     .constant = 0x5a827999UL },
        /** 32 to 47 */
        { .f = md4_f_32_47,     .constant = 0x6ed9eba1UL },
};
 
/** MD4 initial digest values */
static const struct md4_digest md4_init = {
        .h = { 0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476 }
};
 
/**
 * Calculate MD4 digest of accumulated data
 *
 * @v dd                Digest and data block
 * @v digest            Copy of current digest value
 */
static void md4_compress ( struct md4_digest_data *dd,
                           const struct md4_digest *digest ) {
        union {
                struct md4_digest_data dd;
                struct md4_variables v;
        } *u = container_of ( dd, typeof ( *u ), dd );
        struct md4_variables *v = &u->v;
        const struct md4_step *step;
        uint32_t *a = &v->a;
        uint32_t *b = &v->b;
        uint32_t *c = &v->c;
        uint32_t *d = &v->d;
        uint32_t *w = v->w;
        uint32_t f;
        uint32_t temp;
        unsigned int round;
        unsigned int i;
 
        /* Sanity checks */
        build_assert ( &u->dd.digest.h[0] == a );
        build_assert ( &u->dd.digest.h[1] == b );
        build_assert ( &u->dd.digest.h[2] == c );
        build_assert ( &u->dd.digest.h[3] == d );
        build_assert ( &u->dd.data.dword[0] == w );
        build_assert ( sizeof ( u->dd ) == sizeof ( u->v ) );
 
        /* Main loop */
        for ( i = 0 ; i < 48 ; i++ ) {
                round = ( i / 16 );
                step = &md4_steps[round];
                f = step->f ( v, ( i % 16 ) );
                temp = *d;
                *d = *c;
                *c = *b;
                *b = rol32 ( ( *a + f + step->constant ), r[round][ i % 4 ] );
                *a = temp;
                DBGC2 ( &md4_algorithm, "%2d : %08x %08x %08x %08x\n",
                        i, *a, *b, *c, *d );
        }
 
        /* Add chunk to hash */
        for ( i = 0 ; i < 4 ; i++ )
                dd->digest.h[i] += digest->h[i];
}
 
/** MD4 algorithm */
MDHASH_ALGORITHM ( md4, md4_algorithm, md4_compress, __LITTLE_ENDIAN,
                   struct md4_digest_data, md4_init, MD4_DIGEST_SIZE );