denyhosts/clamscan/libclamav/uniq.c

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2022-10-22 18:41:00 +08:00
/*
* md5 based hashtab
*
* Copyright (C) 2013-2022 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
* Copyright (C) 2008-2013 Sourcefire, Inc.
*
* Authors: aCaB <acab@clamav.net>
*
* 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 <stdlib.h>
#if HAVE_STRING_H
#include <string.h>
#endif
#include "clamav.h"
#include "uniq.h"
#include "others.h"
struct uniq *uniq_init(uint32_t count)
{
struct uniq *U;
if (!count) return NULL;
U = cli_calloc(1, sizeof(*U));
if (!U) return NULL;
U->md5s = cli_malloc(count * sizeof(*U->md5s));
if (!U->md5s) {
uniq_free(U);
return NULL;
}
U->max_unique_items = count;
return U;
}
void uniq_free(struct uniq *U)
{
free(U->md5s);
free(U);
}
cl_error_t uniq_add(struct uniq *U, const char *item, uint32_t item_len, char **rhash, uint32_t *count)
{
cl_error_t status = CL_EARG;
unsigned int i;
uint8_t digest[16];
struct UNIQMD5 *m = NULL;
if (!U) {
/* Invalid args */
goto done;
}
/* Uniq adds are limited by the maximum allocated in uniq_init(). */
if (U->cur_unique_items >= U->max_unique_items) {
/* Attempted to add more uniq items than may be stored. */
status = CL_EMAXSIZE;
goto done;
}
/* Make a hash of the item string */
if (NULL == cl_hash_data("md5", item, item_len, digest, NULL)) {
/* Failed to create hash of item. */
status = CL_EFORMAT;
goto done;
}
/* Check for md5 digest match in md5 collection */
if (U->items && U->md5s[U->idx[*digest]].md5[0] == *digest)
for (m = &U->md5s[U->idx[*digest]]; m; m = m->next)
if (!memcmp(&digest[1], &m->md5[1], 15)) break;
if (!m) {
/* No match. Add new md5 to list */
const char HEX[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
m = &U->md5s[U->items];
m->count = 0;
if (U->items && U->md5s[U->idx[*digest]].md5[0] == *digest)
m->next = &U->md5s[U->idx[*digest]];
else
m->next = NULL;
U->idx[*digest] = U->items;
for (i = 0; i < 16; i++) {
m->name[i * 2] = HEX[digest[i] >> 4 & 0xf];
m->name[i * 2 + 1] = HEX[digest[i] & 0xf];
m->md5[i] = digest[i];
}
m->name[32] = '\0';
/* Increment # of unique items. */
U->cur_unique_items++;
}
/* Increment total # of items. */
U->items++;
/* Increment # items matching this md5 digest (probably just this 1). */
m->count++;
/* Pass back the ascii hash, if requested. */
if (rhash) *rhash = m->name;
/* Pass back the count, if requested. */
if (count) *count = m->count;
status = CL_SUCCESS;
done:
return status;
}
cl_error_t uniq_get(struct uniq *U, const char *item, uint32_t item_len, char **rhash, uint32_t *count)
{
cl_error_t status = CL_EARG;
uint8_t digest[16];
struct UNIQMD5 *m = NULL;
uint32_t idx = 0;
if (!U || !count) {
/* Invalid args */
goto done;
}
*count = 0;
if (!U->items) {
goto not_found;
}
/* Make a hash of the item string */
if (NULL == cl_hash_data("md5", item, item_len, digest, NULL)) {
/* Failed to create hash of item. */
status = CL_EFORMAT;
goto done;
}
/* Get the md5s array index for the bucket list head. */
idx = U->idx[*digest];
m = &U->md5s[idx];
if (m->md5[0] != *digest) {
/*
* If the first two bytes in the digest doesn't actually match,
* then the item has never been added.
* This is a common scenario because the idx table is initialized
* to 0's.
*/
goto not_found;
}
do {
if (0 == memcmp(&digest[1], &m->md5[1], 15)) {
/* The item-hash matched.
* Pass back the ascii hash value (if requested).
* Return the count of matching items (will be 1+).
*/
if (rhash)
*rhash = m->name;
*count = m->count;
break;
}
m = m->next;
} while (NULL != m);
not_found:
status = CL_SUCCESS;
done:
return status;
}