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/*

 * 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>

 *

 * 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

 * (at your option) any later version.

 *

 */

#include <linux/init.h>

#include <linux/crypto.h>

#include <linux/kernel.h>

#include <linux/string.h>

#include <asm/byteorder.h>

#define MD4_DIGEST_SIZE         16

#define MD4_HMAC_BLOCK_SIZE     64

#define MD4_BLOCK_WORDS         16

#define MD4_HASH_WORDS          4

struct md4_ctx {

        u32 hash[MD4_HASH_WORDS];

        u32 block[MD4_BLOCK_WORDS];

        u64 byte_count;

};

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))

/* XXX: this stuff can be optimized */

static inline void le32_to_cpu_array(u32 *buf, unsigned int words)

{

        while (words--) {

                __le32_to_cpus(buf);

                buf++;

        }

}

static inline void cpu_to_le32_array(u32 *buf, unsigned int words)

{

        while (words--) {

                __cpu_to_le32s(buf);

                buf++;

        }

}

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, sizeof(ctx->block) / sizeof(u32));

        md4_transform(ctx->hash, ctx->block);

}

static void md4_init(void *ctx)

{

        struct md4_ctx *mctx = ctx;

        mctx->hash[0] = 0x67452301;

        mctx->hash[1] = 0xefcdab89;

        mctx->hash[2] = 0x98badcfe;

        mctx->hash[3] = 0x10325476;

        mctx->byte_count = 0;

}

static void md4_update(void *ctx, const u8 *data, unsigned int len)

{

        struct md4_ctx *mctx = ctx;

        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;

        }

        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);

}

static void md4_final(void *ctx, u8 *out)

{

        struct md4_ctx *mctx = ctx;

        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, sizeof(mctx->hash) / sizeof(u32));

        memcpy(out, mctx->hash, sizeof(mctx->hash));

        memset(mctx, 0, sizeof(*mctx));

}

static struct crypto_alg alg = {

        .cra_name       =       "md4",

        .cra_flags      =       CRYPTO_ALG_TYPE_DIGEST,

        .cra_blocksize  =       MD4_HMAC_BLOCK_SIZE,

        .cra_ctxsize    =       sizeof(struct md4_ctx),

        .cra_module     =       THIS_MODULE,

        .cra_list       =       LIST_HEAD_INIT(alg.cra_list),

        .cra_u          =       { .digest = {

        .dia_digestsize =       MD4_DIGEST_SIZE,

        .dia_init       =       md4_init,

        .dia_update     =       md4_update,

        .dia_final      =       md4_final } }

};

static int __init init(void)

{

        return crypto_register_alg(&alg);

}

static void __exit fini(void)

{

        crypto_unregister_alg(&alg);

}

module_init(init);

module_exit(fini);

MODULE_LICENSE("GPL");

MODULE_DESCRIPTION("MD4 Message Digest Algorithm");