```// 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) 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"

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[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;
md4_transform_helper(mctx);
p = (char *)mctx->block;
}