src/lib/md4.c

/*
 * MD4 (RFC-1320) message digest.
 * Modified from MD5 code by Andrey Panin <pazke@donpac.ru>
 *
 * Written by Solar Designer <solar@openwall.com> in 2001, and placed in
 * the public domain.  There's absolutely no warranty.
 *
 * This differs from Colin Plumb's older public domain implementation in
 * that no 32-bit integer data type is required, there's no compile-time
 * endianness configuration, and the function prototypes match OpenSSL's.
 * The primary goals are portability and ease of use.
 *
 * This implementation is meant to be fast, but not as fast as possible.
 * Some known optimizations are not included to reduce source code size
 * and avoid compile-time configuration.
 */

#include "lib.h"
#include "safe-memset.h"
#include "md4.h"

/*
 * The basic MD4 functions.
 */
#define F(x, y, z)  ((z) ^ ((x) & ((y) ^ (z))))
#define G(x, y, z)  (((x) & (y)) | ((x) & (z)) | ((y) & (z)))
#define H(x, y, z)  ((x) ^ (y) ^ (z))

/*
 * The MD4 transformation for all four rounds.
 */
#define STEP(f, a, b, c, d, x, s) \
    (a) += f((b), (c), (d)) + (x);   \
    (a) = ((a) << (s)) | ((a) >> (32 - (s)))


/*
 * SET reads 4 input bytes in little-endian byte order and stores them
 * in a properly aligned word in host byte order.
 *
 * The check for little-endian architectures which tolerate unaligned
 * memory accesses is just an optimization.  Nothing will break if it
 * doesn't work.
 */
#if defined(__i386__) || defined(__x86_64__) || defined(__vax__)
/* uint_fast32_t might be 64 bit, and thus may read 4 more bytes
 * beyond the end of the buffer. So only read precisely 32 bits
 */
#define SET(n)              \
    (*(const uint32_t *)&ptr[(n) * 4])
#define GET(n) \
    SET(n)
#else
#define SET(n) \
    (ctx->block[(n)] = \
    (uint_fast32_t)ptr[(n) * 4] | \
    ((uint_fast32_t)ptr[(n) * 4 + 1] << 8) | \
    ((uint_fast32_t)ptr[(n) * 4 + 2] << 16) | \
    ((uint_fast32_t)ptr[(n) * 4 + 3] << 24))
#define GET(n) \
    (ctx->block[(n)])
#endif

/*
 * This processes one or more 64-byte data blocks, but does NOT update
 * the bit counters.  There're no alignment requirements.
 */
static const void * ATTR_NOWARN_UNUSED_RESULT ATTR_UNSIGNED_WRAPS
body(struct md4_context *ctx, const void *data, size_t size)
{
    const unsigned char *ptr;
    uint32_t a, b, c, d;
    uint32_t saved_a, saved_b, saved_c, saved_d;

    ptr = data;

    a = ctx->a;
    b = ctx->b;
    c = ctx->c;
    d = ctx->d;

    do {
        saved_a = a;
        saved_b = b;
        saved_c = c;
        saved_d = d;

/* Round 1 */
        STEP(F, a, b, c, d, SET( 0),  3);
        STEP(F, d, a, b, c, SET( 1),  7);
        STEP(F, c, d, a, b, SET( 2), 11);
        STEP(F, b, c, d, a, SET( 3), 19);

        STEP(F, a, b, c, d, SET( 4),  3);
        STEP(F, d, a, b, c, SET( 5),  7);
        STEP(F, c, d, a, b, SET( 6), 11);
        STEP(F, b, c, d, a, SET( 7), 19);

        STEP(F, a, b, c, d, SET( 8),  3);
        STEP(F, d, a, b, c, SET( 9),  7);
        STEP(F, c, d, a, b, SET(10), 11);
        STEP(F, b, c, d, a, SET(11), 19);

        STEP(F, a, b, c, d, SET(12),  3);
        STEP(F, d, a, b, c, SET(13),  7);
        STEP(F, c, d, a, b, SET(14), 11);
        STEP(F, b, c, d, a, SET(15), 19);
/* Round 2 */
        STEP(G, a, b, c, d, GET( 0) + 0x5A827999,  3);
        STEP(G, d, a, b, c, GET( 4) + 0x5A827999,  5);
        STEP(G, c, d, a, b, GET( 8) + 0x5A827999,  9);
        STEP(G, b, c, d, a, GET(12) + 0x5A827999, 13);

        STEP(G, a, b, c, d, GET( 1) + 0x5A827999,  3);
        STEP(G, d, a, b, c, GET( 5) + 0x5A827999,  5);
        STEP(G, c, d, a, b, GET( 9) + 0x5A827999,  9);
        STEP(G, b, c, d, a, GET(13) + 0x5A827999, 13);

        STEP(G, a, b, c, d, GET( 2) + 0x5A827999,  3);
        STEP(G, d, a, b, c, GET( 6) + 0x5A827999,  5);
        STEP(G, c, d, a, b, GET(10) + 0x5A827999,  9);
        STEP(G, b, c, d, a, GET(14) + 0x5A827999, 13);

        STEP(G, a, b, c, d, GET( 3) + 0x5A827999,  3);
        STEP(G, d, a, b, c, GET( 7) + 0x5A827999,  5);
        STEP(G, c, d, a, b, GET(11) + 0x5A827999,  9);
        STEP(G, b, c, d, a, GET(15) + 0x5A827999, 13);
/* Round 3 */
        STEP(H, a, b, c, d, GET( 0) + 0x6ED9EBA1,  3);
        STEP(H, d, a, b, c, GET( 8) + 0x6ED9EBA1,  9);
        STEP(H, c, d, a, b, GET( 4) + 0x6ED9EBA1, 11);
        STEP(H, b, c, d, a, GET(12) + 0x6ED9EBA1, 15);

        STEP(H, a, b, c, d, GET( 2) + 0x6ED9EBA1,  3);
        STEP(H, d, a, b, c, GET(10) + 0x6ED9EBA1,  9);
        STEP(H, c, d, a, b, GET( 6) + 0x6ED9EBA1, 11);
        STEP(H, b, c, d, a, GET(14) + 0x6ED9EBA1, 15);

        STEP(H, a, b, c, d, GET( 1) + 0x6ED9EBA1,  3);
        STEP(H, d, a, b, c, GET( 9) + 0x6ED9EBA1,  9);
        STEP(H, c, d, a, b, GET( 5) + 0x6ED9EBA1, 11);
        STEP(H, b, c, d, a, GET(13) + 0x6ED9EBA1, 15);

        STEP(H, a, b, c, d, GET( 3) + 0x6ED9EBA1,  3);
        STEP(H, d, a, b, c, GET(11) + 0x6ED9EBA1,  9);
        STEP(H, c, d, a, b, GET( 7) + 0x6ED9EBA1, 11);
        STEP(H, b, c, d, a, GET(15) + 0x6ED9EBA1, 15);

        a += saved_a;
        b += saved_b;
        c += saved_c;
        d += saved_d;

        ptr += 64;
    } while ((size -= 64) != 0);

    ctx->a = a;
    ctx->b = b;
    ctx->c = c;
    ctx->d = d;

    return ptr;
}

void md4_init(struct md4_context *ctx)
{
    ctx->a = 0x67452301;
    ctx->b = 0xefcdab89;
    ctx->c = 0x98badcfe;
    ctx->d = 0x10325476;

    ctx->lo = 0;
    ctx->hi = 0;
}

void md4_update(struct md4_context *ctx, const void *data, size_t size)
{
    /* @UNSAFE */
    uint_fast32_t saved_lo;
    unsigned long used, free;

    saved_lo = ctx->lo;
    if ((ctx->lo = (saved_lo + size) & 0x1fffffff) < saved_lo)
        ctx->hi++;
    ctx->hi += size >> 29;

    used = saved_lo & 0x3f;

    if (used != 0) {
        free = 64 - used;

        if (size < free) {
            memcpy(&ctx->buffer[used], data, size);
            return;
        }

        memcpy(&ctx->buffer[used], data, free);
        data = (const unsigned char *) data + free;
        size -= free;
        body(ctx, ctx->buffer, 64);
    }

    if (size >= 64) {
        data = body(ctx, data, size & ~(unsigned long)0x3f);
        size &= 0x3f;
    }

    memcpy(ctx->buffer, data, size);
}

void md4_final(struct md4_context *ctx, unsigned char result[STATIC_ARRAY MD4_RESULTLEN])
{
    /* @UNSAFE */
    unsigned long used, free;

    used = ctx->lo & 0x3f;

    ctx->buffer[used++] = 0x80;

    free = 64 - used;

    if (free < 8) {
        memset(&ctx->buffer[used], 0, free);
        body(ctx, ctx->buffer, 64);
        used = 0;
        free = 64;
    }

    memset(&ctx->buffer[used], 0, free - 8);

    ctx->lo <<= 3;
    ctx->buffer[56] = ctx->lo;
    ctx->buffer[57] = ctx->lo >> 8;
    ctx->buffer[58] = ctx->lo >> 16;
    ctx->buffer[59] = ctx->lo >> 24;
    ctx->buffer[60] = ctx->hi;
    ctx->buffer[61] = ctx->hi >> 8;
    ctx->buffer[62] = ctx->hi >> 16;
    ctx->buffer[63] = ctx->hi >> 24;

    body(ctx, ctx->buffer, 64);

    result[0] = ctx->a;
    result[1] = ctx->a >> 8;
    result[2] = ctx->a >> 16;
    result[3] = ctx->a >> 24;
    result[4] = ctx->b;
    result[5] = ctx->b >> 8;
    result[6] = ctx->b >> 16;
    result[7] = ctx->b >> 24;
    result[8] = ctx->c;
    result[9] = ctx->c >> 8;
    result[10] = ctx->c >> 16;
    result[11] = ctx->c >> 24;
    result[12] = ctx->d;
    result[13] = ctx->d >> 8;
    result[14] = ctx->d >> 16;
    result[15] = ctx->d >> 24;

    i_zero_safe(ctx);
}

void md4_get_digest(const void *data, size_t size,
            unsigned char result[STATIC_ARRAY MD4_RESULTLEN])
{
    struct md4_context ctx;

    md4_init(&ctx);
    md4_update(&ctx, data, size);
    md4_final(&ctx, result);
}

static void hash_method_init_md4(void *context)
{
    md4_init(context);
}
static void hash_method_loop_md4(void *context, const void *data, size_t size)
{
    md4_update(context, data, size);
}

static void hash_method_result_md4(void *context, unsigned char *result_r)
{
    md4_final(context, result_r);
}

const struct hash_method hash_method_md4 = {
    "md4",
    sizeof(struct md4_context),
    MD4_RESULTLEN,

    hash_method_init_md4,
    hash_method_loop_md4,
    hash_method_result_md4
};