denyhosts/clamscan/libclamav/arc4.c

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2022-10-22 18:41:00 +08:00
/*
* Copyright (C) 2013-2022 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
* Copyright (C) 2011-2013 Sourcefire, Inc.
*
* Author: Török Edvin
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
#if HAVE_CONFIG_H
#include "clamav-config.h"
#endif
#include "clamav-types.h"
#include "arc4.h"
#include <string.h>
bool arc4_init(struct arc4_state *a, const uint8_t *key, unsigned keylength)
{
unsigned i;
uint8_t j;
uint32_t *S;
if (NULL == a || NULL == key || 0 == keylength)
return false;
S = &a->S[0];
for (i = 0; i < 256; i++)
S[i] = i;
for (i = 0, j = 0; i < 256; i++) {
uint8_t tmp = S[i];
j = j + S[i] + key[i % keylength];
S[i] = S[j];
S[j] = tmp;
}
a->i = a->j = 0;
return true;
}
void arc4_apply(struct arc4_state *s, uint8_t *data, unsigned len)
{
uint8_t i = s->i, j = s->j;
uint32_t *S = &s->S[0];
while (len-- > 0) {
uint32_t a, b;
i++;
a = S[i];
j += a;
b = S[i] = S[j];
b += a;
S[j] = a;
*data++ ^= S[b & 0xff];
}
s->i = i;
s->j = j;
}
#if 0
#include <sys/time.h>
static struct {
const char *key;
const char *plaintext;
const char *result;
} testdata[] = {
{"Key", "Plaintext", "\xBB\xF3\x16\xE8\xD9\x40\xAF\x0A\xD3"},
{"Wiki", "pedia", "\x10\x21\xBF\x04\x20"},
{"Secret", "Attack at dawn", "\x45\xA0\x1F\x64\x5F\xC3\x5B\x38\x35\x52\x54\x4B\x9B\xF5"}
};
static int data[10*1024*1024];
int main(void)
{
struct arc4_state a;
uint8_t data[32];
size_t i;
struct timeval tv0, tv1;
for (i=0;i<sizeof(testdata)/sizeof(testdata[0]);i++) {
unsigned len;
arc4_init(&a, (const uint8_t*)testdata[i].key, strlen(testdata[i].key));
len = strlen(testdata[i].plaintext);
memcpy(data, testdata[i].plaintext, len);
arc4_apply(&a, data, len);
if (memcmp(data, testdata[i].result, len)) {
printf("Bad result at %zu\n", i);
}
}
gettimeofday(&tv0, NULL);
for (i=0;i<1000000;i++)
arc4_apply(&a, data, sizeof(data));
gettimeofday(&tv1, NULL);
tv1.tv_sec -= tv0.tv_sec;
tv1.tv_usec -= tv0.tv_usec;
printf("Time: %f us\n", tv1.tv_sec*1000000.0 + tv1.tv_usec);
}
#endif