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/*
* zc - zip crack library
* Copyright (C) 2012-2018 Marc Ferland
*
* 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 3 of the License, or
* (at your option) any later version.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include <unistd.h>
#include "libzc_private.h"
#include "decrypt_byte.h"
int fill_header(struct zc_ctx *ctx, const char *filename,
struct zc_header *h,
size_t len)
{
struct zc_file *file;
int err;
err = zc_file_new_from_filename(ctx, filename, &file);
if (err)
return -1;
err = zc_file_open(file);
if (err) {
zc_file_unref(file);
return -1;
}
int size = read_zc_header(file, h, len);
zc_file_close(file);
zc_file_unref(file);
return size;
}
int fill_test_cipher(struct zc_ctx *ctx, const char *filename,
unsigned char **buf, size_t *len,
uint32_t *original_crc, bool *is_deflated)
{
struct zc_file *file;
int err;
err = zc_file_new_from_filename(ctx, filename, &file);
if (err)
goto err1;
err = zc_file_open(file);
if (err)
goto err2;
err = read_crypt_data(file, buf, len, original_crc, is_deflated);
zc_file_close(file);
zc_file_unref(file);
return err ? -1 : 0;
err2:
zc_file_unref(file);
err1:
return -1;
}
void decrypt(const unsigned char *in, unsigned char *out, size_t len,
const struct zc_key *key)
{
struct zc_key k = *key;
for (size_t i = 0; i < len - 1; ++i) {
out[i] = in[i] ^ decrypt_byte_lookup(k.key2);
update_keys(out[i], &k, &k);
}
out[len - 1] = in[len - 1] ^ decrypt_byte_lookup(k.key2);
}
uint8_t decrypt_header(const uint8_t *buf, struct zc_key *k, uint8_t magic)
{
for (size_t i = 0; i < ENC_HEADER_LEN - 1; ++i) {
uint8_t c = buf[i] ^ decrypt_byte_lookup(k->key2);
update_keys(c, k, k);
}
/* Returns the last byte of the decrypted header */
return buf[ENC_HEADER_LEN - 1] ^ decrypt_byte_lookup(k->key2) ^ magic;
}
bool decrypt_headers(const struct zc_key *k, const struct zc_header *h, size_t len)
{
struct zc_key tmp;
for (size_t i = 0; i < len; ++i) {
reset_encryption_keys(k, &tmp);
if (decrypt_header(h[i].buf, &tmp, h[i].magic))
return false;
}
return true;
}
long threads_to_create(long forced)
{
if (forced > 0)
return forced;
long n = sysconf(_SC_NPROCESSORS_ONLN);
if (n < 1)
return 1;
return n;
}
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