// SPDX-License-Identifier: GPL-2.0
/*
 * Cryptographic API.
 *
 * MD4 Message Digest Algorithm (RFC1320).
 *
 * Implementation derived from Andrew Tridgell and Steve French's
 * CIFS MD4 implementation, and the cryptoapi implementation
 * originally based on the public domain implementation written
 * by Colin Plumb in 1993.
 *
 * Copyright (c) Andrew Tridgell 1997-1998.
 * Modified by Steve French (sfrench@us.ibm.com) 2002
 * Copyright (c) Cryptoapi developers.
 * Copyright (c) 2002 David S. Miller (davem@redhat.com)
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 *
 */
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/types.h>
#include <asm/byteorder.h>
#include "md4.h"

MODULE_DESCRIPTION("MD4 Message Digest Algorithm (RFC1320)");
MODULE_LICENSE("GPL");

static inline u32 lshift(u32 x, unsigned int s)
{
        x &= 0xFFFFFFFF;
        return ((x << s) & 0xFFFFFFFF) | (x >> (32 - s));
}

static inline u32 F(u32 x, u32 y, u32 z)
{
        return (x & y) | ((~x) & z);
}

static inline u32 G(u32 x, u32 y, u32 z)
{
        return (x & y) | (x & z) | (y & z);
}

static inline u32 H(u32 x, u32 y, u32 z)
{
        return x ^ y ^ z;
}

#define ROUND1(a,b,c,d,k,s) (a = lshift(a + F(b,c,d) + k, s))
#define ROUND2(a,b,c,d,k,s) (a = lshift(a + G(b,c,d) + k + (u32)0x5A827999,s))
#define ROUND3(a,b,c,d,k,s) (a = lshift(a + H(b,c,d) + k + (u32)0x6ED9EBA1,s))

static void md4_transform(u32 *hash, u32 const *in)
{
        u32 a, b, c, d;

        a = hash[0];
        b = hash[1];
        c = hash[2];
        d = hash[3];

        ROUND1(a, b, c, d, in[0], 3);
        ROUND1(d, a, b, c, in[1], 7);
        ROUND1(c, d, a, b, in[2], 11);
        ROUND1(b, c, d, a, in[3], 19);
        ROUND1(a, b, c, d, in[4], 3);
        ROUND1(d, a, b, c, in[5], 7);
        ROUND1(c, d, a, b, in[6], 11);
        ROUND1(b, c, d, a, in[7], 19);
        ROUND1(a, b, c, d, in[8], 3);
        ROUND1(d, a, b, c, in[9], 7);
        ROUND1(c, d, a, b, in[10], 11);
        ROUND1(b, c, d, a, in[11], 19);
        ROUND1(a, b, c, d, in[12], 3);
        ROUND1(d, a, b, c, in[13], 7);
        ROUND1(c, d, a, b, in[14], 11);
        ROUND1(b, c, d, a, in[15], 19);

        ROUND2(a, b, c, d, in[0], 3);
        ROUND2(d, a, b, c, in[4], 5);
        ROUND2(c, d, a, b, in[8], 9);
        ROUND2(b, c, d, a, in[12], 13);
        ROUND2(a, b, c, d, in[1], 3);
        ROUND2(d, a, b, c, in[5], 5);
        ROUND2(c, d, a, b, in[9], 9);
        ROUND2(b, c, d, a, in[13], 13);
        ROUND2(a, b, c, d, in[2], 3);
        ROUND2(d, a, b, c, in[6], 5);
        ROUND2(c, d, a, b, in[10], 9);
        ROUND2(b, c, d, a, in[14], 13);
        ROUND2(a, b, c, d, in[3], 3);
        ROUND2(d, a, b, c, in[7], 5);
        ROUND2(c, d, a, b, in[11], 9);
        ROUND2(b, c, d, a, in[15], 13);

        ROUND3(a, b, c, d, in[0], 3);
        ROUND3(d, a, b, c, in[8], 9);
        ROUND3(c, d, a, b, in[4], 11);
        ROUND3(b, c, d, a, in[12], 15);
        ROUND3(a, b, c, d, in[2], 3);
        ROUND3(d, a, b, c, in[10], 9);
        ROUND3(c, d, a, b, in[6], 11);
        ROUND3(b, c, d, a, in[14], 15);
        ROUND3(a, b, c, d, in[1], 3);
        ROUND3(d, a, b, c, in[9], 9);
        ROUND3(c, d, a, b, in[5], 11);
        ROUND3(b, c, d, a, in[13], 15);
        ROUND3(a, b, c, d, in[3], 3);
        ROUND3(d, a, b, c, in[11], 9);
        ROUND3(c, d, a, b, in[7], 11);
        ROUND3(b, c, d, a, in[15], 15);

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

static inline void md4_transform_helper(struct md4_ctx *ctx)
{
        le32_to_cpu_array(ctx->block, ARRAY_SIZE(ctx->block));
        md4_transform(ctx->hash, ctx->block);
}

int cifs_md4_init(struct md4_ctx *mctx)
{
        memset(mctx, 0, sizeof(struct md4_ctx));
        mctx->hash[0] = 0x67452301;
        mctx->hash[1] = 0xefcdab89;
        mctx->hash[2] = 0x98badcfe;
        mctx->hash[3] = 0x10325476;
        mctx->byte_count = 0;

        return 0;
}
EXPORT_SYMBOL_GPL(cifs_md4_init);

int cifs_md4_update(struct md4_ctx *mctx, const u8 *data, unsigned int len)
{
        const u32 avail = sizeof(mctx->block) - (mctx->byte_count & 0x3f);

        mctx->byte_count += len;

        if (avail > len) {
                memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
                       data, len);
                return 0;
        }

        memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
               data, avail);

        md4_transform_helper(mctx);
        data += avail;
        len -= avail;

        while (len >= sizeof(mctx->block)) {
                memcpy(mctx->block, data, sizeof(mctx->block));
                md4_transform_helper(mctx);
                data += sizeof(mctx->block);
                len -= sizeof(mctx->block);
        }

        memcpy(mctx->block, data, len);

        return 0;
}
EXPORT_SYMBOL_GPL(cifs_md4_update);

int cifs_md4_final(struct md4_ctx *mctx, u8 *out)
{
        const unsigned int offset = mctx->byte_count & 0x3f;
        char *p = (char *)mctx->block + offset;
        int padding = 56 - (offset + 1);

        *p++ = 0x80;
        if (padding < 0) {
                memset(p, 0x00, padding + sizeof(u64));
                md4_transform_helper(mctx);
                p = (char *)mctx->block;
                padding = 56;
        }

        memset(p, 0, padding);
        mctx->block[14] = mctx->byte_count << 3;
        mctx->block[15] = mctx->byte_count >> 29;
        le32_to_cpu_array(mctx->block, (sizeof(mctx->block) -
                          sizeof(u64)) / sizeof(u32));
        md4_transform(mctx->hash, mctx->block);
        cpu_to_le32_array(mctx->hash, ARRAY_SIZE(mctx->hash));
        memcpy(out, mctx->hash, sizeof(mctx->hash));
        memset(mctx, 0, sizeof(*mctx));

        return 0;
}
EXPORT_SYMBOL_GPL(cifs_md4_final);