[funini.com] -> [kei@sodan] -> Kernel Reading

root/crypto/md5.c

/* [<][>][^][v][top][bottom][index][help] */

DEFINITIONS

This source file includes following definitions.
  1. md5_transform
  2. le32_to_cpu_array
  3. cpu_to_le32_array
  4. md5_transform_helper
  5. md5_init
  6. md5_update
  7. md5_final
  8. md5_mod_init
  9. md5_mod_fini

/* 
 * Cryptographic API.
 *
 * MD5 Message Digest Algorithm (RFC1321).
 *
 * Derived from cryptoapi implementation, originally based on the
 * public domain implementation written by Colin Plumb in 1993.
 *
 * Copyright (c) Cryptoapi developers.
 * 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/module.h>
#include <linux/string.h>
#include <linux/crypto.h>
#include <linux/types.h>
#include <asm/byteorder.h>

#define MD5_DIGEST_SIZE         16
#define MD5_HMAC_BLOCK_SIZE     64
#define MD5_BLOCK_WORDS         16
#define MD5_HASH_WORDS          4

#define F1(x, y, z)     (z ^ (x & (y ^ z)))
#define F2(x, y, z)     F1(z, x, y)
#define F3(x, y, z)     (x ^ y ^ z)
#define F4(x, y, z)     (y ^ (x | ~z))

#define MD5STEP(f, w, x, y, z, in, s) \
        (w += f(x, y, z) + in, w = (w<<s | w>>(32-s)) + x)

struct md5_ctx {
        u32 hash[MD5_HASH_WORDS];
        u32 block[MD5_BLOCK_WORDS];
        u64 byte_count;
};

static void md5_transform(u32 *hash, u32 const *in)
{
        u32 a, b, c, d;

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

        MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
        MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
        MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
        MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
        MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
        MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
        MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
        MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
        MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
        MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
        MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
        MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
        MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
        MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
        MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
        MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

        MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
        MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
        MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
        MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
        MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
        MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
        MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
        MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
        MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
        MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
        MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
        MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
        MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
        MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
        MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
        MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

        MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
        MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
        MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
        MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
        MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
        MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
        MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
        MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
        MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
        MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
        MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
        MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
        MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
        MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
        MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
        MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

        MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
        MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
        MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
        MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
        MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
        MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
        MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
        MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
        MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
        MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
        MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
        MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
        MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
        MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
        MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
        MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);

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

/* 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 inline void md5_transform_helper(struct md5_ctx *ctx)
{
        le32_to_cpu_array(ctx->block, sizeof(ctx->block) / sizeof(u32));
        md5_transform(ctx->hash, ctx->block);
}

static void md5_init(struct crypto_tfm *tfm)
{
        struct md5_ctx *mctx = crypto_tfm_ctx(tfm);

        mctx->hash[0] = 0x67452301;
        mctx->hash[1] = 0xefcdab89;
        mctx->hash[2] = 0x98badcfe;
        mctx->hash[3] = 0x10325476;
        mctx->byte_count = 0;
}

static void md5_update(struct crypto_tfm *tfm, const u8 *data, unsigned int len)
{
        struct md5_ctx *mctx = crypto_tfm_ctx(tfm);
        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);

        md5_transform_helper(mctx);
        data += avail;
        len -= avail;

        while (len >= sizeof(mctx->block)) {
                memcpy(mctx->block, data, sizeof(mctx->block));
                md5_transform_helper(mctx);
                data += sizeof(mctx->block);
                len -= sizeof(mctx->block);
        }

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

static void md5_final(struct crypto_tfm *tfm, u8 *out)
{
        struct md5_ctx *mctx = crypto_tfm_ctx(tfm);
        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));
                md5_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));
        md5_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       =       "md5",
        .cra_flags      =       CRYPTO_ALG_TYPE_DIGEST,
        .cra_blocksize  =       MD5_HMAC_BLOCK_SIZE,
        .cra_ctxsize    =       sizeof(struct md5_ctx),
        .cra_module     =       THIS_MODULE,
        .cra_list       =       LIST_HEAD_INIT(alg.cra_list),
        .cra_u          =       { .digest = {
        .dia_digestsize =       MD5_DIGEST_SIZE,
        .dia_init       =       md5_init,
        .dia_update     =       md5_update,
        .dia_final      =       md5_final } }
};

static int __init md5_mod_init(void)
{
        return crypto_register_alg(&alg);
}

static void __exit md5_mod_fini(void)
{
        crypto_unregister_alg(&alg);
}

module_init(md5_mod_init);
module_exit(md5_mod_fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("MD5 Message Digest Algorithm");

/* [<][>][^][v][top][bottom][index][help] */

[funini.com] -> [kei@sodan] -> Kernel Reading