crypto_internal.c

Go to the documentation of this file.

/*
 * Crypto wrapper for internal crypto implementation
 * Copyright (c) 2006-2009, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "crypto.h"
#include "sha1_i.h"
#include "md5_i.h"

struct crypto_hash {
        enum crypto_hash_alg alg;
        union {
                struct MD5Context md5;
                struct SHA1Context sha1;
        } u;
        u8 key[64];
        size_t key_len;
};


struct crypto_hash * crypto_hash_init(enum crypto_hash_alg alg, const u8 *key,
                                      size_t key_len)
{
        struct crypto_hash *ctx;
        u8 k_pad[64];
        u8 tk[20];
        size_t i;

        ctx = os_zalloc(sizeof(*ctx));
        if (ctx == NULL)
                return NULL;

        ctx->alg = alg;

        switch (alg) {
        case CRYPTO_HASH_ALG_MD5:
                MD5Init(&ctx->u.md5);
                break;
        case CRYPTO_HASH_ALG_SHA1:
                SHA1Init(&ctx->u.sha1);
                break;
        case CRYPTO_HASH_ALG_HMAC_MD5:
                if (key_len > sizeof(k_pad)) {
                        MD5Init(&ctx->u.md5);
                        MD5Update(&ctx->u.md5, key, key_len);
                        MD5Final(tk, &ctx->u.md5);
                        key = tk;
                        key_len = 16;
                }
                os_memcpy(ctx->key, key, key_len);
                ctx->key_len = key_len;

                os_memcpy(k_pad, key, key_len);
                os_memset(k_pad + key_len, 0, sizeof(k_pad) - key_len);
                for (i = 0; i < sizeof(k_pad); i++)
                        k_pad[i] ^= 0x36;
                MD5Init(&ctx->u.md5);
                MD5Update(&ctx->u.md5, k_pad, sizeof(k_pad));
                break;
        case CRYPTO_HASH_ALG_HMAC_SHA1:
                if (key_len > sizeof(k_pad)) {
                        SHA1Init(&ctx->u.sha1);
                        SHA1Update(&ctx->u.sha1, key, key_len);
                        SHA1Final(tk, &ctx->u.sha1);
                        key = tk;
                        key_len = 20;
                }
                os_memcpy(ctx->key, key, key_len);
                ctx->key_len = key_len;

                os_memcpy(k_pad, key, key_len);
                os_memset(k_pad + key_len, 0, sizeof(k_pad) - key_len);
                for (i = 0; i < sizeof(k_pad); i++)
                        k_pad[i] ^= 0x36;
                SHA1Init(&ctx->u.sha1);
                SHA1Update(&ctx->u.sha1, k_pad, sizeof(k_pad));
                break;
        default:
                os_free(ctx);
                return NULL;
        }

        return ctx;
}


void crypto_hash_update(struct crypto_hash *ctx, const u8 *data, size_t len)
{
        if (ctx == NULL)
                return;

        switch (ctx->alg) {
        case CRYPTO_HASH_ALG_MD5:
        case CRYPTO_HASH_ALG_HMAC_MD5:
                MD5Update(&ctx->u.md5, data, len);
                break;
        case CRYPTO_HASH_ALG_SHA1:
        case CRYPTO_HASH_ALG_HMAC_SHA1:
                SHA1Update(&ctx->u.sha1, data, len);
                break;
        }
}


int crypto_hash_finish(struct crypto_hash *ctx, u8 *mac, size_t *len)
{
        u8 k_pad[64];
        size_t i;

        if (ctx == NULL)
                return -2;

        if (mac == NULL || len == NULL) {
                os_free(ctx);
                return 0;
        }

        switch (ctx->alg) {
        case CRYPTO_HASH_ALG_MD5:
                if (*len < 16) {
                        *len = 16;
                        os_free(ctx);
                        return -1;
                }
                *len = 16;
                MD5Final(mac, &ctx->u.md5);
                break;
        case CRYPTO_HASH_ALG_SHA1:
                if (*len < 20) {
                        *len = 20;
                        os_free(ctx);
                        return -1;
                }
                *len = 20;
                SHA1Final(mac, &ctx->u.sha1);
                break;
        case CRYPTO_HASH_ALG_HMAC_MD5:
                if (*len < 16) {
                        *len = 16;
                        os_free(ctx);
                        return -1;
                }
                *len = 16;

                MD5Final(mac, &ctx->u.md5);

                os_memcpy(k_pad, ctx->key, ctx->key_len);
                os_memset(k_pad + ctx->key_len, 0,
                          sizeof(k_pad) - ctx->key_len);
                for (i = 0; i < sizeof(k_pad); i++)
                        k_pad[i] ^= 0x5c;
                MD5Init(&ctx->u.md5);
                MD5Update(&ctx->u.md5, k_pad, sizeof(k_pad));
                MD5Update(&ctx->u.md5, mac, 16);
                MD5Final(mac, &ctx->u.md5);
                break;
        case CRYPTO_HASH_ALG_HMAC_SHA1:
                if (*len < 20) {
                        *len = 20;
                        os_free(ctx);
                        return -1;
                }
                *len = 20;

                SHA1Final(mac, &ctx->u.sha1);

                os_memcpy(k_pad, ctx->key, ctx->key_len);
                os_memset(k_pad + ctx->key_len, 0,
                          sizeof(k_pad) - ctx->key_len);
                for (i = 0; i < sizeof(k_pad); i++)
                        k_pad[i] ^= 0x5c;
                SHA1Init(&ctx->u.sha1);
                SHA1Update(&ctx->u.sha1, k_pad, sizeof(k_pad));
                SHA1Update(&ctx->u.sha1, mac, 20);
                SHA1Final(mac, &ctx->u.sha1);
                break;
        }

        os_free(ctx);

        return 0;
}


int crypto_global_init(void)
{
        return 0;
}


void crypto_global_deinit(void)
{
}