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denyhosts/clamav/libclamav/matcher-ac.c

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/*
* Copyright (C) 2013-2022 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
* Copyright (C) 2007-2013 Sourcefire, Inc.
*
* Authors: Tomasz Kojm
*
* 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 <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <sys/stat.h>
#include <assert.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include "clamav.h"
#include "others.h"
#include "matcher.h"
#include "matcher-ac.h"
#include "filetypes.h"
#include "str.h"
#include "readdb.h"
#include "default.h"
#include "filtering.h"
#include "mpool.h"
// clang-format off
#define AC_SPECIAL_ALT_CHAR 1
#define AC_SPECIAL_ALT_STR_FIXED 2
#define AC_SPECIAL_ALT_STR 3
#define AC_SPECIAL_LINE_MARKER 4
#define AC_SPECIAL_BOUNDARY 5
#define AC_SPECIAL_WORD_MARKER 6
#define AC_BOUNDARY_LEFT 0x0001
#define AC_BOUNDARY_LEFT_NEGATIVE 0x0002
#define AC_BOUNDARY_RIGHT 0x0004
#define AC_BOUNDARY_RIGHT_NEGATIVE 0x0008
#define AC_LINE_MARKER_LEFT 0x0010
#define AC_LINE_MARKER_LEFT_NEGATIVE 0x0020
#define AC_LINE_MARKER_RIGHT 0x0040
#define AC_LINE_MARKER_RIGHT_NEGATIVE 0x0080
#define AC_WORD_MARKER_LEFT 0x0100
#define AC_WORD_MARKER_LEFT_NEGATIVE 0x0200
#define AC_WORD_MARKER_RIGHT 0x0400
#define AC_WORD_MARKER_RIGHT_NEGATIVE 0x0800
static char boundary[256] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 2, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
3, 0, 2, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 3, 1, 3,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 2, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
// clang-format on
static inline int insert_list(struct cli_matcher *root, struct cli_ac_patt *pattern, struct cli_ac_node *pt)
{
struct cli_ac_list *new;
struct cli_ac_list **newtable;
new = (struct cli_ac_list *)MPOOL_CALLOC(root->mempool, 1, sizeof(struct cli_ac_list));
if (!new) {
cli_errmsg("cli_ac_addpatt: Can't allocate memory for list node\n");
return CL_EMEM;
}
new->me = pattern;
new->node = pt;
root->ac_lists++;
newtable = MPOOL_REALLOC(root->mempool, root->ac_listtable, root->ac_lists * sizeof(struct cli_ac_list *));
if (!newtable) {
root->ac_lists--;
cli_errmsg("cli_ac_addpatt: Can't realloc ac_listtable\n");
MPOOL_FREE(root->mempool, new);
return CL_EMEM;
}
root->ac_listtable = newtable;
root->ac_listtable[root->ac_lists - 1] = new;
return CL_SUCCESS;
}
#define RETURN_RES_IF_NE(uia, uib) \
do { \
if (uia < uib) return -1; \
if (uia > uib) return +1; \
} while (0)
static int patt_cmp_fn(const struct cli_ac_patt *a, const struct cli_ac_patt *b)
{
unsigned int i;
int res;
RETURN_RES_IF_NE(a->length[0], b->length[0]);
RETURN_RES_IF_NE(a->prefix_length[0], b->prefix_length[0]);
RETURN_RES_IF_NE(a->ch[0], b->ch[0]);
RETURN_RES_IF_NE(a->ch[1], b->ch[1]);
RETURN_RES_IF_NE(a->boundary, b->boundary);
/*
* If the first two arguments to memcmp are NULL, clangs
* UndefinedBehaviorSanitizer will complain. It is legal if the length
* is zero, so don't call memcmp if the length is zero.
*/
if (a->length[0] > 0) {
res = memcmp(a->pattern, b->pattern, a->length[0] * sizeof(uint16_t));
if (res) {
return res;
}
}
if (a->prefix_length[0] > 0) {
res = memcmp(a->prefix, b->prefix, a->prefix_length[0] * sizeof(uint16_t));
if (res) {
return res;
}
}
RETURN_RES_IF_NE(a->special, b->special);
if (!a->special && !b->special)
return 0;
for (i = 0; i < a->special; i++) {
struct cli_ac_special *spcl_a = a->special_table[i], *spcl_b = b->special_table[i];
RETURN_RES_IF_NE(spcl_a->num, spcl_b->num);
RETURN_RES_IF_NE(spcl_a->negative, spcl_b->negative);
RETURN_RES_IF_NE(spcl_a->type, spcl_b->type);
if (spcl_a->type == AC_SPECIAL_ALT_CHAR) {
res = memcmp((spcl_a->alt).byte, (spcl_b->alt).byte, spcl_a->num);
if (res) return res;
} else if (spcl_a->type == AC_SPECIAL_ALT_STR_FIXED) {
unsigned int j;
RETURN_RES_IF_NE(spcl_a->len[0], spcl_b->len[0]);
for (j = 0; j < spcl_a->num; j++) {
res = memcmp((spcl_a->alt).f_str[j], (spcl_b->alt).f_str[j], spcl_a->len[0]);
if (res) return res;
}
} else if (spcl_a->type == AC_SPECIAL_ALT_STR) {
struct cli_alt_node *alt_a = (spcl_a->alt).v_str, *alt_b = (spcl_b->alt).v_str;
while (alt_a && alt_b) {
RETURN_RES_IF_NE(alt_a->len, alt_b->len);
res = memcmp(alt_a->str, alt_b->str, alt_a->len);
if (res) return res;
alt_a = alt_a->next;
alt_b = alt_b->next;
}
RETURN_RES_IF_NE(alt_a, alt_b);
}
}
return 0;
}
static int sort_list_fn(const void *a, const void *b)
{
const struct cli_ac_node *node_a = (*(const struct cli_ac_list **)a)->node;
const struct cli_ac_node *node_b = (*(const struct cli_ac_list **)b)->node;
const struct cli_ac_patt *patt_a = (*(const struct cli_ac_list **)a)->me;
const struct cli_ac_patt *patt_b = (*(const struct cli_ac_list **)b)->me;
int res;
/* 1. Group by owning node
* (this is for assigning entries to nodes) */
RETURN_RES_IF_NE(node_a, node_b);
/* 2. Group together equal pattern in a node
* (this is for building the next_same list) */
res = patt_cmp_fn(patt_a, patt_b);
if (res)
return res;
/* 3. Sort equal patterns in a node by partno in ascending order
* (this is required by the matcher) */
RETURN_RES_IF_NE(patt_a->partno, patt_b->partno);
/* 4. Keep close patterns close
* (this is for performace) */
RETURN_RES_IF_NE(patt_a, patt_b);
return 0;
}
static int sort_heads_by_partno_fn(const void *a, const void *b)
{
const struct cli_ac_list *list_a = *(const struct cli_ac_list **)a;
const struct cli_ac_list *list_b = *(const struct cli_ac_list **)b;
const struct cli_ac_patt *patt_a = list_a->me;
const struct cli_ac_patt *patt_b = list_b->me;
/* 1. Sort heads by partno
* (this is required by the matcher) */
RETURN_RES_IF_NE(patt_a->partno, patt_b->partno);
/* 2. Place longer lists earlier
* (this is for performance) */
while (1) {
if (!list_a->next_same) {
if (!list_b->next_same)
break;
return +1;
}
if (!list_b->next_same)
return -1;
list_a = list_a->next_same;
list_b = list_b->next_same;
}
/* 3. Keep close patterns close
* (this is for performace) */
RETURN_RES_IF_NE(patt_a, patt_b);
return 0;
}
static inline void link_node_lists(struct cli_ac_list **listtable, unsigned int nentries)
{
struct cli_ac_list *prev = listtable[0];
struct cli_ac_node *node = prev->node;
unsigned int i, nheads = 1;
/* Link equal patterns in the next_same list (entries are already sorted by partno asc) */
for (i = 1; i < nentries; i++) {
int ret = patt_cmp_fn(prev->me, listtable[i]->me);
if (ret) {
/* This is a new head of a next_same chain */
prev = listtable[i];
if (i != nheads) {
/* Move heads towards the beginning of the table */
listtable[i] = listtable[nheads];
listtable[nheads] = prev;
}
nheads++;
} else {
prev->next_same = listtable[i];
prev->next = NULL;
prev = listtable[i];
}
}
cli_qsort(listtable, nheads, sizeof(listtable[0]), sort_heads_by_partno_fn);
/* Link heads in the next list */
node->list = listtable[0];
for (i = 1; i < nheads; i++)
listtable[i - 1]->next = listtable[i];
listtable[nheads - 1]->next = NULL;
}
static void link_lists(struct cli_matcher *root)
{
struct cli_ac_node *curnode;
unsigned int i, grouplen;
if (!root->ac_lists)
return;
/* Group the list by owning node, pattern equality and sort by partno */
cli_qsort(root->ac_listtable, root->ac_lists, sizeof(root->ac_listtable[0]), sort_list_fn);
curnode = root->ac_listtable[0]->node;
for (i = 1, grouplen = 1; i <= root->ac_lists; i++, grouplen++) {
if (i == root->ac_lists || root->ac_listtable[i]->node != curnode) {
link_node_lists(&root->ac_listtable[i - grouplen], grouplen);
if (i < root->ac_lists) {
grouplen = 0;
curnode = root->ac_listtable[i]->node;
}
}
}
}
/**
* @brief Inserts newly malloced trans node in the array of nodes to be freed on
* cleanup. There is no verification that the added node is not already in the
* list, so that is up to the caller.
*
* @param root The matcher root.
* @param trans The trans node to be tracked.
* @return bool
*/
static bool store_trans_node(struct cli_matcher *root, struct cli_ac_node **trans)
{
bool bRet = false;
if (root->trans_cnt + 1 > root->trans_capacity) {
size_t newCapacity = root->trans_capacity + 1024;
struct cli_ac_node ***ret = MPOOL_REALLOC(root->mempool, root->trans_array, newCapacity * sizeof(struct cli_ac_node **));
if (NULL == ret) {
cli_errmsg("cli_ac_addpatt: Can't allocate memory for cleanup storage of trans\n");
goto done;
}
root->trans_capacity = newCapacity;
root->trans_array = ret;
}
root->trans_array[root->trans_cnt++] = trans;
bRet = true;
done:
return bRet;
}
/**
* @brief Frees all trans nodes for cleanup.
* cleanup.
*
* @param root The matcher root.
*/
static void free_trans_nodes(struct cli_matcher *root)
{
uint32_t i = 0;
for (i = 0; i < root->trans_cnt; i++) {
MPOOL_FREE(root->mempool, root->trans_array[i]);
}
MPOOL_FREE(root->mempool, root->trans_array);
root->trans_array = NULL;
root->trans_cnt = 0;
root->trans_capacity = 0;
}
static inline struct cli_ac_node *add_new_node(struct cli_matcher *root, uint16_t i, uint16_t len)
{
struct cli_ac_node *new;
struct cli_ac_node **newtable;
new = (struct cli_ac_node *)MPOOL_CALLOC(root->mempool, 1, sizeof(struct cli_ac_node));
if (!new) {
cli_errmsg("cli_ac_addpatt: Can't allocate memory for AC node\n");
return NULL;
}
if (i != len - 1) {
new->trans = (struct cli_ac_node **)MPOOL_CALLOC(root->mempool, 256, sizeof(struct cli_ac_node *));
if (!new->trans) {
cli_errmsg("cli_ac_addpatt: Can't allocate memory for new->trans\n");
MPOOL_FREE(root->mempool, new);
return NULL;
}
if (!store_trans_node(root, new->trans)) {
/* Error printed in store_trans_node */
MPOOL_FREE(root->mempool, new);
return NULL;
}
}
root->ac_nodes++;
newtable = MPOOL_REALLOC(root->mempool, root->ac_nodetable, root->ac_nodes * sizeof(struct cli_ac_node *));
if (!newtable) {
root->ac_nodes--;
cli_errmsg("cli_ac_addpatt: Can't realloc ac_nodetable\n");
if (new->trans)
MPOOL_FREE(root->mempool, new->trans);
MPOOL_FREE(root->mempool, new);
return NULL;
}
root->ac_nodetable = newtable;
root->ac_nodetable[root->ac_nodes - 1] = new;
return new;
}
static int cli_ac_addpatt_recursive(struct cli_matcher *root, struct cli_ac_patt *pattern, struct cli_ac_node *pt, uint16_t i, uint16_t len)
{
struct cli_ac_node *next;
int ret;
/* last node, insert pattern here (base case)*/
if (i >= len) {
return insert_list(root, pattern, pt);
}
/* if current node has no trans table, generate one */
if (!pt->trans) {
pt->trans = (struct cli_ac_node **)MPOOL_CALLOC(root->mempool, 256, sizeof(struct cli_ac_node *));
if (!pt->trans) {
cli_errmsg("cli_ac_addpatt: Can't allocate memory for pt->trans\n");
return CL_EMEM;
}
if (!store_trans_node(root, pt->trans)) {
/* Error printed in store_trans_node */
return CL_EMEM;
}
}
/* if pattern is nocase, we need to enumerate all the combinations if applicable
* it's why this function was re-written to be recursive
*/
if ((pattern->sigopts & ACPATT_OPTION_NOCASE) && (pattern->pattern[i] & 0xff) < 0x80 && isalpha((unsigned char)(pattern->pattern[i] & 0xff))) {
next = pt->trans[CLI_NOCASEI((unsigned char)(pattern->pattern[i] & 0xff))];
if (!next)
next = add_new_node(root, i, len);
if (!next)
return CL_EMEM;
else
pt->trans[CLI_NOCASEI((unsigned char)(pattern->pattern[i] & 0xff))] = next;
if ((ret = cli_ac_addpatt_recursive(root, pattern, next, i + 1, len)) != CL_SUCCESS)
return ret;
}
/* normal transition, also enumerates the 'normal' nocase */
next = pt->trans[(unsigned char)(pattern->pattern[i] & 0xff)];
if (!next)
next = add_new_node(root, i, len);
if (!next)
return CL_EMEM;
else
pt->trans[(unsigned char)(pattern->pattern[i] & 0xff)] = next;
return cli_ac_addpatt_recursive(root, pattern, next, i + 1, len);
}
cl_error_t cli_ac_addpatt(struct cli_matcher *root, struct cli_ac_patt *pattern)
{
struct cli_ac_patt **newtable;
uint16_t len = MIN(root->ac_maxdepth, pattern->length[0]);
uint16_t i;
for (i = 0; i < len; i++) {
if (pattern->pattern[i] & CLI_MATCH_WILDCARD) {
len = i;
break;
}
}
if (len < root->ac_mindepth) {
/* cli_errmsg("cli_ac_addpatt: Signature for %s is too short\n", pattern->virname); */
return CL_EMALFDB;
}
/* pattern added to master list */
root->ac_patterns++;
newtable = MPOOL_REALLOC(root->mempool, root->ac_pattable, root->ac_patterns * sizeof(struct cli_ac_patt *));
if (!newtable) {
root->ac_patterns--;
cli_errmsg("cli_ac_addpatt: Can't realloc ac_pattable\n");
return CL_EMEM;
}
root->ac_pattable = newtable;
root->ac_pattable[root->ac_patterns - 1] = pattern;
pattern->depth = len;
return cli_ac_addpatt_recursive(root, pattern, root->ac_root, 0, len);
}
struct bfs_list {
struct cli_ac_node *node;
struct bfs_list *next;
};
static int bfs_enqueue(struct bfs_list **bfs, struct bfs_list **last, struct cli_ac_node *n)
{
struct bfs_list *new;
new = (struct bfs_list *)cli_malloc(sizeof(struct bfs_list));
if (!new) {
cli_errmsg("bfs_enqueue: Can't allocate memory for bfs_list\n");
return CL_EMEM;
}
new->next = NULL;
new->node = n;
if (*last) {
(*last)->next = new;
*last = new;
} else {
*bfs = *last = new;
}
return CL_SUCCESS;
}
static struct cli_ac_node *bfs_dequeue(struct bfs_list **bfs, struct bfs_list **last)
{
struct bfs_list *lpt;
struct cli_ac_node *pt;
if (!(lpt = *bfs)) {
return NULL;
} else {
*bfs = (*bfs)->next;
pt = lpt->node;
if (lpt == *last)
*last = NULL;
free(lpt);
return pt;
}
}
static int ac_maketrans(struct cli_matcher *root)
{
struct bfs_list *bfs = NULL, *bfs_last = NULL;
struct cli_ac_node *ac_root = root->ac_root, *child, *node, *fail;
int i, ret;
for (i = 0; i < 256; i++) {
node = ac_root->trans[i];
if (!node) {
ac_root->trans[i] = ac_root;
} else {
node->fail = ac_root;
if ((ret = bfs_enqueue(&bfs, &bfs_last, node)))
return ret;
}
}
while ((node = bfs_dequeue(&bfs, &bfs_last))) {
if (IS_LEAF(node)) {
struct cli_ac_node *failtarget = node->fail;
while (NULL != failtarget && (IS_LEAF(failtarget) || !IS_FINAL(failtarget)))
failtarget = failtarget->fail;
if (NULL != failtarget)
node->fail = failtarget;
continue;
}
for (i = 0; i < 256; i++) {
child = node->trans[i];
if (child) {
fail = node->fail;
while (IS_LEAF(fail) || !fail->trans[i])
fail = fail->fail;
child->fail = fail->trans[i];
if ((ret = bfs_enqueue(&bfs, &bfs_last, child)) != 0)
return ret;
}
}
}
bfs = bfs_last = NULL;
for (i = 0; i < 256; i++) {
node = ac_root->trans[i];
if (node != ac_root) {
if ((ret = bfs_enqueue(&bfs, &bfs_last, node)))
return ret;
}
}
while ((node = bfs_dequeue(&bfs, &bfs_last))) {
if (IS_LEAF(node))
continue;
for (i = 0; i < 256; i++) {
child = node->trans[i];
if (!child || (!IS_FINAL(child) && IS_LEAF(child))) {
struct cli_ac_node *failtarget = node->fail;
while (IS_LEAF(failtarget) || !failtarget->trans[i])
failtarget = failtarget->fail;
failtarget = failtarget->trans[i];
node->trans[i] = failtarget;
} else if (IS_FINAL(child) && IS_LEAF(child)) {
struct cli_ac_list *list;
list = child->list;
if (list) {
while (list->next)
list = list->next;
list->next = child->fail->list;
} else {
child->list = child->fail->list;
}
child->trans = child->fail->trans;
} else {
if ((ret = bfs_enqueue(&bfs, &bfs_last, child)) != 0)
return ret;
}
}
}
return CL_SUCCESS;
}
cl_error_t cli_ac_buildtrie(struct cli_matcher *root)
{
if (!root)
return CL_EMALFDB;
if (!(root->ac_root)) {
cli_dbgmsg("cli_ac_buildtrie: AC pattern matcher is not initialised\n");
return CL_SUCCESS;
}
if (root->filter)
cli_dbgmsg("Using filter for trie %d\n", root->type);
link_lists(root);
return ac_maketrans(root);
}
cl_error_t cli_ac_init(struct cli_matcher *root, uint8_t mindepth, uint8_t maxdepth, uint8_t dconf_prefiltering)
{
#ifdef USE_MPOOL
assert(root->mempool && "mempool must be initialized");
#endif
root->ac_root = (struct cli_ac_node *)MPOOL_CALLOC(root->mempool, 1, sizeof(struct cli_ac_node));
if (!root->ac_root) {
cli_errmsg("cli_ac_init: Can't allocate memory for ac_root\n");
return CL_EMEM;
}
root->ac_root->trans = (struct cli_ac_node **)MPOOL_CALLOC(root->mempool, 256, sizeof(struct cli_ac_node *));
if (!root->ac_root->trans) {
cli_errmsg("cli_ac_init: Can't allocate memory for ac_root->trans\n");
MPOOL_FREE(root->mempool, root->ac_root);
return CL_EMEM;
}
root->ac_mindepth = mindepth;
root->ac_maxdepth = maxdepth;
if (cli_mtargets[root->type].enable_prefiltering && dconf_prefiltering) {
root->filter = MPOOL_MALLOC(root->mempool, sizeof(*root->filter));
if (!root->filter) {
cli_errmsg("cli_ac_init: Can't allocate memory for ac_root->filter\n");
MPOOL_FREE(root->mempool, root->ac_root->trans);
MPOOL_FREE(root->mempool, root->ac_root);
return CL_EMEM;
}
filter_init(root->filter);
}
return CL_SUCCESS;
}
#ifdef USE_MPOOL
#define mpool_ac_free_special(a, b) ac_free_special(a, b)
static void ac_free_special(mpool_t *mempool, struct cli_ac_patt *p)
#else
#define mpool_ac_free_special(a, b) ac_free_special(b)
static void ac_free_special(struct cli_ac_patt *p)
#endif
{
unsigned int i, j;
struct cli_ac_special *a1;
struct cli_alt_node *b1, *b2;
if (!p->special)
return;
for (i = 0; i < p->special; i++) {
a1 = p->special_table[i];
if (a1->type == AC_SPECIAL_ALT_CHAR) {
MPOOL_FREE(mempool, (a1->alt).byte);
} else if (a1->type == AC_SPECIAL_ALT_STR_FIXED) {
for (j = 0; j < a1->num; j++)
MPOOL_FREE(mempool, (a1->alt).f_str[j]);
MPOOL_FREE(mempool, (a1->alt).f_str);
} else if (a1->type == AC_SPECIAL_ALT_STR) {
b1 = (a1->alt).v_str;
while (b1) {
b2 = b1->next;
MPOOL_FREE(mempool, b1->str);
MPOOL_FREE(mempool, b1);
b1 = b2;
}
}
MPOOL_FREE(mempool, a1);
}
MPOOL_FREE(mempool, p->special_table);
}
void cli_ac_free(struct cli_matcher *root)
{
uint32_t i = 0;
struct cli_ac_patt *patt = NULL;
for (i = 0; i < root->ac_patterns; i++) {
patt = root->ac_pattable[i];
MPOOL_FREE(root->mempool, patt->prefix ? patt->prefix : patt->pattern);
if (!(patt->lsigid[0] == 1)) {
/* Don't free the virname for patterns lsigs (normal or yara).
For lsigs, we store the virname in lsig->virname, not in each ac-pattern.
TODO: never store the virname in the ac pattern and only store it per-signature, not per-pattern. */
MPOOL_FREE(root->mempool, patt->virname);
}
if (patt->special) {
mpool_ac_free_special(root->mempool, patt);
}
MPOOL_FREE(root->mempool, patt);
}
if (root->ac_pattable) {
MPOOL_FREE(root->mempool, root->ac_pattable);
}
if (root->ac_reloff) {
MPOOL_FREE(root->mempool, root->ac_reloff);
}
for (i = 0; i < root->ac_lists; i++) {
MPOOL_FREE(root->mempool, root->ac_listtable[i]);
}
if (root->ac_listtable) {
MPOOL_FREE(root->mempool, root->ac_listtable);
}
for (i = 0; i < root->ac_nodes; i++) {
MPOOL_FREE(root->mempool, root->ac_nodetable[i]);
}
if (root->ac_nodetable) {
MPOOL_FREE(root->mempool, root->ac_nodetable);
}
if (root->ac_root) {
MPOOL_FREE(root->mempool, root->ac_root->trans);
MPOOL_FREE(root->mempool, root->ac_root);
}
if (root->filter) {
MPOOL_FREE(root->mempool, root->filter);
}
free_trans_nodes(root);
}
/*
* In parse_only mode this function returns -1 on error or the max subsig id
*/
int cli_ac_chklsig(const char *expr, const char *end, uint32_t *lsigcnt, unsigned int *cnt, uint64_t *ids, unsigned int parse_only)
{
unsigned int i, len = end - expr, pth = 0, opoff = 0, op1off = 0, val;
unsigned int blkend = 0, id, modval1, modval2 = 0, lcnt = 0, rcnt = 0, tcnt, modoff = 0;
uint64_t lids = 0, rids = 0, tids;
int ret, lval, rval;
char op = 0, op1 = 0, mod = 0, blkmod = 0;
const char *lstart = expr, *lend = NULL, *rstart = NULL, *rend = end, *pt;
for (i = 0; i < len; i++) {
switch (expr[i]) {
case '(':
pth++;
break;
case ')':
if (!pth) {
cli_errmsg("cli_ac_chklsig: Syntax error: Missing opening parenthesis\n");
return -1;
}
pth--;
/* fall-through */
case '>':
case '<':
case '=':
mod = expr[i];
modoff = i;
break;
default:
if (strchr("&|", expr[i])) {
if (!pth) {
op = expr[i];
opoff = i;
} else if (pth == 1) {
op1 = expr[i];
op1off = i;
}
}
}
if (op)
break;
if (op1 && !pth) {
blkend = i;
if (expr[i + 1] == '>' || expr[i + 1] == '<' || expr[i + 1] == '=') {
blkmod = expr[i + 1];
ret = sscanf(&expr[i + 2], "%u,%u", &modval1, &modval2);
if (ret != 2)
ret = sscanf(&expr[i + 2], "%u", &modval1);
if (!ret || ret == EOF) {
cli_errmsg("chklexpr: Syntax error: Missing number after '%c'\n", expr[i + 1]);
return -1;
}
for (i += 2; i + 1 < len && (isdigit(expr[i + 1]) || expr[i + 1] == ','); i++)
;
}
if (&expr[i + 1] == rend)
break;
else
blkmod = 0;
}
}
if (pth) {
cli_errmsg("cli_ac_chklsig: Syntax error: Missing closing parenthesis\n");
return -1;
}
if (!op && !op1) {
if (expr[0] == '(')
return cli_ac_chklsig(++expr, --end, lsigcnt, cnt, ids, parse_only);
ret = sscanf(expr, "%u", &id);
if (!ret || ret == EOF) {
cli_errmsg("cli_ac_chklsig: Can't parse %s\n", expr);
return -1;
}
if (parse_only)
val = id;
else
val = lsigcnt[id];
if (mod) {
pt = expr + modoff + 1;
ret = sscanf(pt, "%u", &modval1);
if (!ret || ret == EOF) {
cli_errmsg("chklexpr: Syntax error: Missing number after '%c'\n", mod);
return -1;
}
if (!parse_only) {
switch (mod) {
case '=':
if (val != modval1)
return 0;
break;
case '<':
if (val >= modval1)
return 0;
break;
case '>':
if (val <= modval1)
return 0;
break;
default:
return 0;
}
*cnt += val;
*ids |= (uint64_t)1 << id;
return 1;
}
}
if (parse_only) {
return val;
} else {
if (val) {
*cnt += val;
*ids |= (uint64_t)1 << id;
return 1;
} else {
return 0;
}
}
}
if (!op) {
op = op1;
opoff = op1off;
lstart++;
rend = &expr[blkend];
}
if (!opoff) {
cli_errmsg("cli_ac_chklsig: Syntax error: Missing left argument\n");
return -1;
}
lend = &expr[opoff];
if (opoff + 1 == len) {
cli_errmsg("cli_ac_chklsig: Syntax error: Missing right argument\n");
return -1;
}
rstart = &expr[opoff + 1];
lval = cli_ac_chklsig(lstart, lend, lsigcnt, &lcnt, &lids, parse_only);
if (lval == -1) {
cli_errmsg("cli_ac_chklsig: Calculation of lval failed\n");
return -1;
}
rval = cli_ac_chklsig(rstart, rend, lsigcnt, &rcnt, &rids, parse_only);
if (rval == -1) {
cli_errmsg("cli_ac_chklsig: Calculation of rval failed\n");
return -1;
}
if (parse_only) {
switch (op) {
case '&':
case '|':
return MAX(lval, rval);
default:
cli_errmsg("cli_ac_chklsig: Incorrect operator type\n");
return -1;
}
} else {
switch (op) {
case '&':
ret = lval && rval;
break;
case '|':
ret = lval || rval;
break;
default:
cli_errmsg("cli_ac_chklsig: Incorrect operator type\n");
return -1;
}
if (!blkmod) {
if (ret) {
*cnt += lcnt + rcnt;
*ids |= lids | rids;
}
return ret;
} else {
if (ret) {
tcnt = lcnt + rcnt;
tids = lids | rids;
} else {
tcnt = 0;
tids = 0;
}
switch (blkmod) {
case '=':
if (tcnt != modval1)
return 0;
break;
case '<':
if (tcnt >= modval1)
return 0;
break;
case '>':
if (tcnt <= modval1)
return 0;
break;
default:
return 0;
}
if (modval2) {
val = 0;
while (tids) {
val += tids & (uint64_t)1;
tids >>= 1;
}
if (val < modval2)
return 0;
}
*cnt += tcnt;
return 1;
}
}
}
inline static int ac_findmatch_special(const unsigned char *buffer, uint32_t offset, uint32_t bp, uint32_t fileoffset, uint32_t length,
const struct cli_ac_patt *pattern, uint32_t pp, uint16_t specialcnt, uint32_t *start, uint32_t *end, int rev);
static int ac_backward_match_branch(const unsigned char *buffer, uint32_t bp, uint32_t offset, uint32_t length, uint32_t fileoffset,
const struct cli_ac_patt *pattern, uint32_t pp, uint16_t specialcnt, uint32_t *start, uint32_t *end);
static int ac_forward_match_branch(const unsigned char *buffer, uint32_t bp, uint32_t offset, uint32_t length, uint32_t fileoffset,
const struct cli_ac_patt *pattern, uint32_t pp, uint16_t specialcnt, uint32_t *start, uint32_t *end);
/* call only by ac_findmatch_special! Does not handle recursive specials */
#define AC_MATCH_CHAR2(p, b) \
switch (wc = p & CLI_MATCH_METADATA) { \
case CLI_MATCH_CHAR: \
if ((unsigned char)p != b) \
match = 0; \
break; \
\
case CLI_MATCH_NOCASE: \
if ((unsigned char)(p & 0xff) != CLI_NOCASE(b)) \
match = 0; \
break; \
\
case CLI_MATCH_IGNORE: \
break; \
\
case CLI_MATCH_NIBBLE_HIGH: \
if ((unsigned char)(p & 0x00f0) != (b & 0xf0)) \
match = 0; \
break; \
\
case CLI_MATCH_NIBBLE_LOW: \
if ((unsigned char)(p & 0x000f) != (b & 0x0f)) \
match = 0; \
break; \
\
default: \
cli_errmsg("ac_findmatch: Unknown metatype 0x%x\n", wc); \
match = 0; \
}
/* call only by ac_XX_match_branch! */
#define AC_MATCH_CHAR(p, b, rev) \
switch (wc = p & CLI_MATCH_METADATA) { \
case CLI_MATCH_CHAR: \
if ((unsigned char)p != b) \
match = 0; \
break; \
\
case CLI_MATCH_NOCASE: \
if ((unsigned char)(p & 0xff) != CLI_NOCASE(b)) \
match = 0; \
break; \
\
case CLI_MATCH_IGNORE: \
break; \
\
case CLI_MATCH_SPECIAL: \
/* >1 = movement, 0 = fail, <1 = resolved in branch */ \
if ((match = ac_findmatch_special(buffer, offset, bp, fileoffset, length, \
pattern, i, specialcnt, start, end, rev)) <= 0) \
return match; \
\
if (!rev) { \
bp += (match - 1); /* -1 is for bp++ in parent loop */ \
specialcnt++; \
} else { \
bp = bp + 1 - match; /* +1 is for bp-- in parent loop */ \
specialcnt--; \
} \
\
break; \
\
case CLI_MATCH_NIBBLE_HIGH: \
if ((unsigned char)(p & 0x00f0) != (b & 0xf0)) \
match = 0; \
break; \
\
case CLI_MATCH_NIBBLE_LOW: \
if ((unsigned char)(p & 0x000f) != (b & 0x0f)) \
match = 0; \
break; \
\
default: \
cli_errmsg("ac_findmatch: Unknown metatype 0x%x\n", wc); \
match = 0; \
}
/* special handler */
inline static int ac_findmatch_special(const unsigned char *buffer, uint32_t offset, uint32_t bp, uint32_t fileoffset, uint32_t length,
const struct cli_ac_patt *pattern, uint32_t pp, uint16_t specialcnt, uint32_t *start, uint32_t *end, int rev)
{
int match, cmp;
uint16_t j, b = buffer[bp];
uint16_t wc;
uint32_t subbp;
struct cli_ac_special *special = pattern->special_table[specialcnt];
struct cli_alt_node *alt = NULL;
match = special->negative;
switch (special->type) {
case AC_SPECIAL_ALT_CHAR: /* single-byte */
for (j = 0; j < special->num; j++) {
cmp = b - (special->alt).byte[j];
if (cmp == 0) {
match = !special->negative;
break;
} else if (cmp < 0)
break;
}
break;
case AC_SPECIAL_ALT_STR_FIXED: /* fixed length multi-byte */
if (!rev) {
if (bp + special->len[0] > length)
break;
subbp = bp;
} else {
if (bp < (uint32_t)(special->len[0] - 1))
break;
subbp = bp - (uint32_t)(special->len[0] - 1);
}
match *= special->len[0];
for (j = 0; j < special->num; j++) {
cmp = memcmp(&buffer[subbp], (special->alt).f_str[j], special->len[0]);
if (cmp == 0) {
match = (!special->negative) * special->len[0];
break;
} else if (cmp < 0)
break;
}
break;
case AC_SPECIAL_ALT_STR: /* generic */
alt = (special->alt).v_str;
while (alt) {
if (!rev) {
if (bp + alt->len > length) {
alt = alt->next;
continue;
}
subbp = bp;
} else {
if (bp < (uint32_t)(alt->len - 1)) {
alt = alt->next;
continue;
}
subbp = bp - (uint32_t)(alt->len - 1);
}
/* note that generic alternates CANNOT be negated */
match = 1;
for (j = 0; j < alt->len; j++) {
AC_MATCH_CHAR2(alt->str[j], buffer[subbp + j]);
if (!match)
break;
}
if (match) {
/* if match is unique (has no derivatives), we can pass it directly back */
if (alt->unique) {
match = alt->len;
break;
}
/* branch for backtracking */
if (!rev)
match = ac_forward_match_branch(buffer, subbp + alt->len, offset, fileoffset, length, pattern, pp + 1, specialcnt + 1, start, end);
else
match = ac_backward_match_branch(buffer, subbp - 1, offset, fileoffset, length, pattern, pp - 1, specialcnt - 1, start, end);
if (match)
return -1; /* alerts caller that match has been resolved in child callee */
}
alt = alt->next;
}
break;
case AC_SPECIAL_LINE_MARKER:
if (b == '\n')
match = !special->negative;
else if (b == '\r' && (bp + 1 < length && buffer[bp + 1] == '\n'))
match = (!special->negative) * 2;
break;
case AC_SPECIAL_BOUNDARY:
if (boundary[b])
match = !special->negative;
break;
case AC_SPECIAL_WORD_MARKER:
if (!isalnum(b))
match = !special->negative;
break;
default:
cli_errmsg("ac_findmatch: Unknown special\n");
match = 0;
}
return match;
}
/* state should reset on call, recursion depth = number of alternate specials */
/* each loop iteration starts on the NEXT sequence to be validated */
static int ac_backward_match_branch(const unsigned char *buffer, uint32_t bp, uint32_t offset, uint32_t fileoffset, uint32_t length,
const struct cli_ac_patt *pattern, uint32_t pp, uint16_t specialcnt, uint32_t *start, uint32_t *end)
{
int match = 0;
uint16_t wc, i;
uint32_t filestart;
/* backwards (prefix) validation, determines start */
if (pattern->prefix && pattern->prefix_length[0]) {
match = 1;
for (i = pp; 1; i--) {
AC_MATCH_CHAR(pattern->prefix[i], buffer[bp], 1);
if (!match)
return 0;
/* needs to perform check before decrement due to unsignedness */
if (i == 0 || bp == 0)
break;
bp--;
}
*start = bp;
filestart = fileoffset - offset + bp;
} else {
/* bp is set to buffer offset */
*start = bp = offset;
filestart = fileoffset;
}
/* left-side special checks, bp = start */
if (pattern->boundary & AC_BOUNDARY_LEFT) {
match = !!(pattern->boundary & AC_BOUNDARY_LEFT_NEGATIVE);
if (!filestart || (bp && (boundary[buffer[bp - 1]] == 1 || boundary[buffer[bp - 1]] == 3)))
match = !match;
if (!match)
return 0;
}
if (pattern->boundary & AC_LINE_MARKER_LEFT) {
match = !!(pattern->boundary & AC_LINE_MARKER_LEFT_NEGATIVE);
if (!filestart || (bp && (buffer[bp - 1] == '\n')))
match = !match;
if (!match)
return 0;
}
if (pattern->boundary & AC_WORD_MARKER_LEFT) {
match = !!(pattern->boundary & AC_WORD_MARKER_LEFT_NEGATIVE);
if (!filestart)
match = !match;
else if (pattern->sigopts & ACPATT_OPTION_WIDE) {
if (filestart - 1 == 0)
match = !match;
if (bp - 1 && bp && !(isalnum(buffer[bp - 2]) && buffer[bp - 1] == '\0'))
match = !match;
} else if (bp && !isalnum(buffer[bp - 1]))
match = !match;
if (!match)
return 0;
}
/* bp is shifted for left anchor check, thus invalidated as pattern start */
if (!(pattern->ch[0] & CLI_MATCH_IGNORE)) {
if (pattern->ch_mindist[0] + (uint32_t)1 > bp)
return 0;
bp -= pattern->ch_mindist[0] + 1;
for (i = pattern->ch_mindist[0]; i <= pattern->ch_maxdist[0]; i++) {
match = 1;
AC_MATCH_CHAR(pattern->ch[0], buffer[bp], 1);
if (match)
break;
if (!bp)
return 0;
else
bp--;
}
if (!match)
return 0;
}
return 1;
}
/* state should reset on call, recursion depth = number of alternate specials */
/* each loop iteration starts on the NEXT sequence to validate */
static int ac_forward_match_branch(const unsigned char *buffer, uint32_t bp, uint32_t offset, uint32_t fileoffset, uint32_t length,
const struct cli_ac_patt *pattern, uint32_t pp, uint16_t specialcnt, uint32_t *start, uint32_t *end)
{
int match;
uint16_t wc, i;
match = 1;
/* forward (pattern) validation; determines end */
for (i = pp; i < pattern->length[0] && bp < length; i++) {
AC_MATCH_CHAR(pattern->pattern[i], buffer[bp], 0);
if (!match)
return 0;
bp++;
}
*end = bp;
/* right-side special checks, bp = end */
if (pattern->boundary & AC_BOUNDARY_RIGHT) {
match = !!(pattern->boundary & AC_BOUNDARY_RIGHT_NEGATIVE);
if ((length <= SCANBUFF) && (bp == length || boundary[buffer[bp]] >= 2))
match = !match;
if (!match)
return 0;
}
if (pattern->boundary & AC_LINE_MARKER_RIGHT) {
match = !!(pattern->boundary & AC_LINE_MARKER_RIGHT_NEGATIVE);
if ((length <= SCANBUFF) && (bp == length || buffer[bp] == '\n' || (buffer[bp] == '\r' && bp + 1 < length && buffer[bp + 1] == '\n')))
match = !match;
if (!match)
return 0;
}
if (pattern->boundary & AC_WORD_MARKER_RIGHT) {
match = !!(pattern->boundary & AC_WORD_MARKER_RIGHT_NEGATIVE);
if (length <= SCANBUFF) {
if (bp == length)
match = !match;
else if ((pattern->sigopts & ACPATT_OPTION_WIDE) && (bp + 1 < length)) {
if (!(isalnum(buffer[bp]) && buffer[bp + 1] == '\0'))
match = !match;
} else if (!isalnum(buffer[bp]))
match = !match;
}
if (!match)
return 0;
}
/* bp is shifted for right anchor check, thus invalidated as pattern right-side */
if (!(pattern->ch[1] & CLI_MATCH_IGNORE)) {
bp += pattern->ch_mindist[1];
for (i = pattern->ch_mindist[1]; i <= pattern->ch_maxdist[1]; i++) {
if (bp >= length)
return 0;
match = 1;
AC_MATCH_CHAR(pattern->ch[1], buffer[bp], 0);
if (match)
break;
bp++;
}
if (!match)
return 0;
}
return ac_backward_match_branch(buffer, offset - 1, offset, fileoffset, length, pattern, pattern->prefix_length[0] - 1, pattern->special_pattern - 1, start, end);
}
inline static int ac_findmatch(const unsigned char *buffer, uint32_t offset, uint32_t fileoffset, uint32_t length, const struct cli_ac_patt *pattern, uint32_t *start, uint32_t *end)
{
int match;
uint16_t specialcnt = pattern->special_pattern;
/* minimal check as the maximum variable length may exceed the buffer */
if ((offset + pattern->length[1] > length) || (pattern->prefix_length[1] > offset))
return 0;
match = ac_forward_match_branch(buffer, offset + pattern->depth, offset, fileoffset, length, pattern, pattern->depth, specialcnt, start, end);
if (match)
return 1;
return 0;
}
cl_error_t cli_ac_initdata(struct cli_ac_data *data, uint32_t partsigs, uint32_t lsigs, uint32_t reloffsigs, uint8_t tracklen)
{
unsigned int i, j;
UNUSEDPARAM(tracklen);
if (!data) {
cli_errmsg("cli_ac_init: data == NULL\n");
return CL_ENULLARG;
}
memset((void *)data, 0, sizeof(struct cli_ac_data));
data->reloffsigs = reloffsigs;
if (reloffsigs) {
data->offset = (uint32_t *)cli_malloc(reloffsigs * 2 * sizeof(uint32_t));
if (!data->offset) {
cli_errmsg("cli_ac_init: Can't allocate memory for data->offset\n");
return CL_EMEM;
}
for (i = 0; i < reloffsigs * 2; i += 2)
data->offset[i] = CLI_OFF_NONE;
}
data->partsigs = partsigs;
if (partsigs) {
data->offmatrix = (uint32_t ***)cli_calloc(partsigs, sizeof(uint32_t **));
if (!data->offmatrix) {
cli_errmsg("cli_ac_init: Can't allocate memory for data->offmatrix\n");
if (reloffsigs)
free(data->offset);
return CL_EMEM;
}
}
data->lsigs = lsigs;
if (lsigs) {
data->lsigcnt = (uint32_t **)cli_malloc(lsigs * sizeof(uint32_t *));
if (!data->lsigcnt) {
if (partsigs)
free(data->offmatrix);
if (reloffsigs)
free(data->offset);
cli_errmsg("cli_ac_init: Can't allocate memory for data->lsigcnt\n");
return CL_EMEM;
}
data->lsigcnt[0] = (uint32_t *)cli_calloc(lsigs * 64, sizeof(uint32_t));
if (!data->lsigcnt[0]) {
free(data->lsigcnt);
if (partsigs)
free(data->offmatrix);
if (reloffsigs)
free(data->offset);
cli_errmsg("cli_ac_init: Can't allocate memory for data->lsigcnt[0]\n");
return CL_EMEM;
}
for (i = 1; i < lsigs; i++)
data->lsigcnt[i] = data->lsigcnt[0] + 64 * i;
data->yr_matches = (uint8_t *)cli_calloc(lsigs, sizeof(uint8_t));
if (data->yr_matches == NULL) {
free(data->lsigcnt[0]);
free(data->lsigcnt);
if (partsigs)
free(data->offmatrix);
if (reloffsigs)
free(data->offset);
return CL_EMEM;
}
/* subsig offsets */
data->lsig_matches = (struct cli_lsig_matches **)cli_calloc(lsigs, sizeof(struct cli_lsig_matches *));
if (!data->lsig_matches) {
free(data->yr_matches);
free(data->lsigcnt[0]);
free(data->lsigcnt);
if (partsigs)
free(data->offmatrix);
if (reloffsigs)
free(data->offset);
cli_errmsg("cli_ac_init: Can't allocate memory for data->lsig_matches\n");
return CL_EMEM;
}
data->lsigsuboff_last = (uint32_t **)cli_malloc(lsigs * sizeof(uint32_t *));
data->lsigsuboff_first = (uint32_t **)cli_malloc(lsigs * sizeof(uint32_t *));
if (!data->lsigsuboff_last || !data->lsigsuboff_first) {
free(data->lsig_matches);
free(data->lsigsuboff_last);
free(data->lsigsuboff_first);
free(data->yr_matches);
free(data->lsigcnt[0]);
free(data->lsigcnt);
if (partsigs)
free(data->offmatrix);
if (reloffsigs)
free(data->offset);
cli_errmsg("cli_ac_init: Can't allocate memory for data->lsigsuboff_(last|first)\n");
return CL_EMEM;
}
data->lsigsuboff_last[0] = (uint32_t *)cli_calloc(lsigs * 64, sizeof(uint32_t));
data->lsigsuboff_first[0] = (uint32_t *)cli_calloc(lsigs * 64, sizeof(uint32_t));
if (!data->lsigsuboff_last[0] || !data->lsigsuboff_first[0]) {
free(data->lsig_matches);
free(data->lsigsuboff_last[0]);
free(data->lsigsuboff_first[0]);
free(data->lsigsuboff_last);
free(data->lsigsuboff_first);
free(data->yr_matches);
free(data->lsigcnt[0]);
free(data->lsigcnt);
if (partsigs)
free(data->offmatrix);
if (reloffsigs)
free(data->offset);
cli_errmsg("cli_ac_init: Can't allocate memory for data->lsigsuboff_(last|first)[0]\n");
return CL_EMEM;
}
for (j = 0; j < 64; j++) {
data->lsigsuboff_last[0][j] = CLI_OFF_NONE;
data->lsigsuboff_first[0][j] = CLI_OFF_NONE;
}
for (i = 1; i < lsigs; i++) {
data->lsigsuboff_last[i] = data->lsigsuboff_last[0] + 64 * i;
data->lsigsuboff_first[i] = data->lsigsuboff_first[0] + 64 * i;
for (j = 0; j < 64; j++) {
data->lsigsuboff_last[i][j] = CLI_OFF_NONE;
data->lsigsuboff_first[i][j] = CLI_OFF_NONE;
}
}
}
for (i = 0; i < 32; i++)
data->macro_lastmatch[i] = CLI_OFF_NONE;
data->min_partno = 1;
return CL_SUCCESS;
}
cl_error_t cli_ac_caloff(const struct cli_matcher *root, struct cli_ac_data *data, const struct cli_target_info *info)
{
cl_error_t ret;
unsigned int i;
struct cli_ac_patt *patt;
if (info)
data->vinfo = &info->exeinfo.vinfo;
for (i = 0; i < root->ac_reloff_num; i++) {
patt = root->ac_reloff[i];
if (!info) {
data->offset[patt->offset_min] = CLI_OFF_NONE;
} else if (CL_SUCCESS != (ret = cli_caloff(NULL, info, root->type, patt->offdata, &data->offset[patt->offset_min], &data->offset[patt->offset_max]))) {
cli_errmsg("cli_ac_caloff: Can't calculate relative offset in signature for %s\n", patt->virname);
return ret;
} else if ((data->offset[patt->offset_min] != CLI_OFF_NONE) && (data->offset[patt->offset_min] + patt->length[1] > info->fsize)) {
data->offset[patt->offset_min] = CLI_OFF_NONE;
}
}
return CL_SUCCESS;
}
void cli_ac_freedata(struct cli_ac_data *data)
{
uint32_t i;
if (!data)
return;
if (data->partsigs) {
for (i = 0; i < data->partsigs; i++) {
if (data->offmatrix[i]) {
free(data->offmatrix[i][0]);
free(data->offmatrix[i]);
}
}
free(data->offmatrix);
data->offmatrix = NULL;
data->partsigs = 0;
}
if (data->lsigs) {
if (data->lsig_matches) {
for (i = 0; i < data->lsigs; i++) {
struct cli_lsig_matches *ls_matches;
if ((ls_matches = data->lsig_matches[i])) {
uint32_t j;
for (j = 0; j < ls_matches->subsigs; j++) {
if (ls_matches->matches[j]) {
free(ls_matches->matches[j]);
ls_matches->matches[j] = 0;
}
}
free(data->lsig_matches[i]);
data->lsig_matches[i] = 0;
}
}
free(data->lsig_matches);
data->lsig_matches = 0;
}
free(data->yr_matches);
free(data->lsigcnt[0]);
free(data->lsigcnt);
free(data->lsigsuboff_last[0]);
free(data->lsigsuboff_last);
free(data->lsigsuboff_first[0]);
free(data->lsigsuboff_first);
data->lsigs = 0;
}
if (data->reloffsigs) {
free(data->offset);
data->reloffsigs = 0;
}
}
/* returns only CL_SUCCESS or CL_EMEM */
inline static int ac_addtype(struct cli_matched_type **list, cli_file_t type, off_t offset, const cli_ctx *ctx)
{
struct cli_matched_type *tnode, *tnode_last;
if (type == CL_TYPE_ZIPSFX) {
if (*list && ctx && ctx->engine->maxfiles && (*list)->cnt > ctx->engine->maxfiles)
return CL_SUCCESS;
} else if (*list && (*list)->cnt >= MAX_EMBEDDED_OBJ) {
return CL_SUCCESS;
}
if (!(tnode = cli_calloc(1, sizeof(struct cli_matched_type)))) {
cli_errmsg("cli_ac_addtype: Can't allocate memory for new type node\n");
return CL_EMEM;
}
tnode->type = type;
tnode->offset = offset;
tnode_last = *list;
while (tnode_last && tnode_last->next)
tnode_last = tnode_last->next;
if (tnode_last)
tnode_last->next = tnode;
else
*list = tnode;
(*list)->cnt++;
return CL_SUCCESS;
}
void lsig_increment_subsig_match(struct cli_ac_data *mdata, uint32_t lsig_id, uint32_t subsig_id)
{
mdata->lsigcnt[lsig_id][subsig_id]++;
}
cl_error_t lsig_sub_matched(const struct cli_matcher *root, struct cli_ac_data *mdata, uint32_t lsig_id, uint32_t subsig_id, uint32_t realoff, int partial)
{
const struct cli_ac_lsig *ac_lsig = root->ac_lsigtable[lsig_id];
const struct cli_lsig_tdb *tdb = &ac_lsig->tdb;
if (realoff != CLI_OFF_NONE) {
if (mdata->lsigsuboff_first[lsig_id][subsig_id] == CLI_OFF_NONE) {
/* If this is the first subsig in the lsig, store the offset in the first-list. */
mdata->lsigsuboff_first[lsig_id][subsig_id] = realoff;
}
if (mdata->lsigsuboff_last[lsig_id][subsig_id] != CLI_OFF_NONE &&
/* If this isn't the first subsig match for this logical sig and the offset
is earlier in the file than the last subsig match, don't count it. */
((!partial && realoff <= mdata->lsigsuboff_last[lsig_id][subsig_id]) ||
(partial && realoff < mdata->lsigsuboff_last[lsig_id][subsig_id]))) {
return CL_SUCCESS;
}
/* Increment the subsig count for this logical signature */
mdata->lsigcnt[lsig_id][subsig_id]++;
if (mdata->lsigcnt[lsig_id][subsig_id] <= 1 || !tdb->macro_ptids || !tdb->macro_ptids[subsig_id]) {
/* Store the offset of this subsig match in the last-list (except in certain circumstances) */
mdata->lsigsuboff_last[lsig_id][subsig_id] = realoff;
}
if (ac_lsig->type & CLI_YARA_OFFSET) {
/*
* There are 3 types of logical signatures: normal, yara-normal, and yara-offset
*
* For yara-offset logical signatures we allocate some structures to
* store yara subsignature match offsets.
*/
struct cli_subsig_matches *ss_matches;
struct cli_lsig_matches *ls_matches;
cli_dbgmsg("lsig_sub_matched lsig %u:%u at %u\n", lsig_id, subsig_id, realoff);
ls_matches = mdata->lsig_matches[lsig_id];
if (ls_matches == NULL) { /* allocate cli_lsig_matches */
ls_matches = mdata->lsig_matches[lsig_id] = (struct cli_lsig_matches *)cli_calloc(1, sizeof(struct cli_lsig_matches) +
(ac_lsig->tdb.subsigs - 1) * sizeof(struct cli_subsig_matches *));
if (ls_matches == NULL) {
cli_errmsg("lsig_sub_matched: cli_calloc failed for cli_lsig_matches\n");
return CL_EMEM;
}
ls_matches->subsigs = ac_lsig->tdb.subsigs;
}
ss_matches = ls_matches->matches[subsig_id];
if (ss_matches == NULL) { /* allocate cli_subsig_matches */
ss_matches = ls_matches->matches[subsig_id] = cli_malloc(sizeof(struct cli_subsig_matches));
if (ss_matches == NULL) {
cli_errmsg("lsig_sub_matched: cli_malloc failed for cli_subsig_matches struct\n");
return CL_EMEM;
}
ss_matches->next = 0;
ss_matches->last = sizeof(ss_matches->offsets) / sizeof(uint32_t) - 1;
}
if (ss_matches->next > ss_matches->last) { /* cli_matches out of space? realloc */
ss_matches = ls_matches->matches[subsig_id] = cli_realloc(ss_matches, sizeof(struct cli_subsig_matches) + sizeof(uint32_t) * ss_matches->last * 2);
if (ss_matches == NULL) {
cli_errmsg("lsig_sub_matched: cli_realloc failed for cli_subsig_matches struct\n");
return CL_EMEM;
}
ss_matches->last = sizeof(ss_matches->offsets) / sizeof(uint32_t) + ss_matches->last * 2 - 1;
}
ss_matches->offsets[ss_matches->next] = realoff; /* finally, store the offset */
ss_matches->next++;
}
}
if ((tdb->macro_ptids != NULL) &&
(tdb->macro_ptids[subsig_id] > 0) &&
(mdata->lsigcnt[lsig_id][subsig_id] > 1)) {
/*
* This logical signature has a macro subsignature and this current subsignature has a macro following it.
*
* Check that the previous match had a macro match following it at the correct distance.
* This check is only done after the 1st match.
*/
const struct cli_ac_patt *macropt;
uint32_t id, last_macro_match, smin, smax, macro_group_id, last_macroprev_match;
/*
* Look up the subsig for the upcoming macro to get anchor-min/max, and macro group id.
* Reminder: A macro subsignature takes the form:
* ${anchor_min - anchor_max} macro_group_id$
*/
id = tdb->macro_ptids[subsig_id];
macropt = root->ac_pattable[id];
smin = macropt->ch_mindist[0];
smax = macropt->ch_maxdist[0];
macro_group_id = macropt->sigid;
/* start of last macro match */
last_macro_match = mdata->macro_lastmatch[macro_group_id];
/* start of previous lsig subsig match */
last_macroprev_match = mdata->lsigsuboff_last[lsig_id][subsig_id];
if (last_macro_match == CLI_OFF_NONE ||
last_macroprev_match + smin > last_macro_match ||
last_macroprev_match + smax < last_macro_match) {
cli_dbgmsg("Canceled false lsig macro match\n");
/* Previous match was false - cancel it */
mdata->lsigcnt[lsig_id][subsig_id]--;
mdata->lsigsuboff_last[lsig_id][subsig_id] = realoff;
} else {
/* mark the macro sig itself matched */
cli_dbgmsg("Checking macro match: %u + (%u - %u) == %u\n",
last_macroprev_match, smin, smax, last_macro_match);
mdata->lsigcnt[lsig_id][subsig_id + 1]++;
mdata->lsigsuboff_last[lsig_id][subsig_id + 1] = last_macro_match;
}
}
return CL_SUCCESS;
}
cl_error_t cli_ac_chkmacro(struct cli_matcher *root, struct cli_ac_data *data, unsigned lsig_id)
{
const struct cli_lsig_tdb *tdb = &root->ac_lsigtable[lsig_id]->tdb;
unsigned i;
cl_error_t rc;
/* Loop through all subsigs, and if they are tied to macros check that the
* macro matched at a correct distance */
for (i = 0; i < tdb->subsigs; i++) {
rc = lsig_sub_matched(root, data, lsig_id, i, CLI_OFF_NONE, 0);
if (rc != CL_SUCCESS)
return rc;
}
return CL_SUCCESS;
}
cl_error_t cli_ac_scanbuff(
const unsigned char *buffer,
uint32_t length,
const char **virname,
void **customdata,
struct cli_ac_result **res,
const struct cli_matcher *root,
struct cli_ac_data *mdata,
uint32_t offset,
cli_file_t ftype,
struct cli_matched_type **ftoffset,
unsigned int mode,
cli_ctx *ctx)
{
struct cli_ac_node *current;
struct cli_ac_list *pattN, *ptN;
struct cli_ac_patt *patt, *pt;
uint32_t i, bp, exptoff[2], realoff, matchstart, matchend;
uint16_t j;
uint8_t found, viruses_found = 0;
uint32_t **offmatrix, swp;
cli_file_t type = CL_TYPE_ANY;
struct cli_ac_result *newres;
cl_error_t rc;
cl_error_t ret;
if (!root->ac_root)
return CL_CLEAN;
if (!mdata && (root->ac_partsigs || root->ac_lsigs || root->ac_reloff_num)) {
cli_errmsg("cli_ac_scanbuff: mdata == NULL\n");
return CL_ENULLARG;
}
current = root->ac_root;
for (i = 0; i < length; i++) {
current = current->trans[buffer[i]];
if (UNLIKELY(IS_FINAL(current))) {
struct cli_ac_list *faillist = current->fail->list;
pattN = current->list;
while (pattN) {
patt = pattN->me;
if (patt->partno > mdata->min_partno) {
pattN = faillist;
faillist = NULL;
continue;
}
bp = i + 1 - patt->depth;
if (patt->offdata[0] != CLI_OFF_VERSION && patt->offdata[0] != CLI_OFF_MACRO && !pattN->next_same && (patt->offset_min != CLI_OFF_ANY) && (!patt->sigid || patt->partno == 1)) {
if (patt->offset_min == CLI_OFF_NONE) {
pattN = pattN->next;
continue;
}
exptoff[0] = offset + bp - patt->prefix_length[2]; /* lower offset end */
exptoff[1] = offset + bp - patt->prefix_length[1]; /* higher offset end */
if (patt->offdata[0] == CLI_OFF_ABSOLUTE) {
if (patt->offset_max < exptoff[0] || patt->offset_min > exptoff[1]) {
pattN = pattN->next;
continue;
}
} else {
if (mdata->offset[patt->offset_min] == CLI_OFF_NONE || mdata->offset[patt->offset_max] < exptoff[0] || mdata->offset[patt->offset_min] > exptoff[1]) {
pattN = pattN->next;
continue;
}
}
}
ptN = pattN;
if (ac_findmatch(buffer, bp, offset + bp, length, patt, &matchstart, &matchend)) {
while (ptN) {
pt = ptN->me;
if (pt->partno > mdata->min_partno)
break;
if ((pt->type && !(mode & AC_SCAN_FT)) || (!pt->type && !(mode & AC_SCAN_VIR))) {
ptN = ptN->next_same;
continue;
}
realoff = offset + matchstart;
if (pt->offdata[0] == CLI_OFF_VERSION) {
if (false == cli_hashset_contains_maybe_noalloc(mdata->vinfo, realoff)) {
ptN = ptN->next_same;
continue;
}
cli_dbgmsg("cli_ac_scanbuff: VI match for offset %x\n", realoff);
} else if (pt->offdata[0] == CLI_OFF_MACRO) {
mdata->macro_lastmatch[patt->offdata[1]] = realoff;
ptN = ptN->next_same;
continue;
} else if (pt->offset_min != CLI_OFF_ANY && (!pt->sigid || pt->partno == 1)) {
if (pt->offset_min == CLI_OFF_NONE) {
ptN = ptN->next_same;
continue;
}
if (pt->offdata[0] == CLI_OFF_ABSOLUTE) {
if (pt->offset_max < realoff || pt->offset_min > realoff) {
ptN = ptN->next_same;
continue;
}
} else {
if (mdata->offset[pt->offset_min] == CLI_OFF_NONE || mdata->offset[pt->offset_max] < realoff || mdata->offset[pt->offset_min] > realoff) {
ptN = ptN->next_same;
continue;
}
}
}
if (pt->sigid) { /* it's a partial signature */
/* if 2nd or later part, confirm some prior part has matched */
if (pt->partno != 1 && (!mdata->offmatrix[pt->sigid - 1] || !mdata->offmatrix[pt->sigid - 1][pt->partno - 2][0])) {
ptN = ptN->next_same;
continue;
}
if ((uint32_t)(pt->partno + 1) > mdata->min_partno)
mdata->min_partno = pt->partno + 1;
/* sparsely populated matrix, so allocate and initialize if NULL */
if (!mdata->offmatrix[pt->sigid - 1]) {
mdata->offmatrix[pt->sigid - 1] = cli_malloc(pt->parts * sizeof(int32_t *));
if (!mdata->offmatrix[pt->sigid - 1]) {
cli_errmsg("cli_ac_scanbuff: Can't allocate memory for mdata->offmatrix[%u]\n", pt->sigid - 1);
return CL_EMEM;
}
mdata->offmatrix[pt->sigid - 1][0] = cli_malloc(pt->parts * (CLI_DEFAULT_AC_TRACKLEN + 2) * sizeof(uint32_t));
if (!mdata->offmatrix[pt->sigid - 1][0]) {
cli_errmsg("cli_ac_scanbuff: Can't allocate memory for mdata->offmatrix[%u][0]\n", pt->sigid - 1);
free(mdata->offmatrix[pt->sigid - 1]);
mdata->offmatrix[pt->sigid - 1] = NULL;
return CL_EMEM;
}
memset(mdata->offmatrix[pt->sigid - 1][0], (uint32_t)-1, pt->parts * (CLI_DEFAULT_AC_TRACKLEN + 2) * sizeof(uint32_t));
mdata->offmatrix[pt->sigid - 1][0][0] = 0;
for (j = 1; j < pt->parts; j++) {
mdata->offmatrix[pt->sigid - 1][j] = mdata->offmatrix[pt->sigid - 1][0] + j * (CLI_DEFAULT_AC_TRACKLEN + 2);
mdata->offmatrix[pt->sigid - 1][j][0] = 0;
}
}
offmatrix = mdata->offmatrix[pt->sigid - 1];
found = 0;
if (pt->partno != 1) {
for (j = 1; (j <= CLI_DEFAULT_AC_TRACKLEN + 1) && (offmatrix[pt->partno - 2][j] != (uint32_t)-1); j++) {
found = j;
if (realoff < offmatrix[pt->partno - 2][j])
found = 0;
if (found && pt->maxdist)
if (realoff - offmatrix[pt->partno - 2][j] > pt->maxdist)
found = 0;
if (found && pt->mindist)
if (realoff - offmatrix[pt->partno - 2][j] < pt->mindist)
found = 0;
if (found)
break;
}
}
if (pt->partno == 2 && found > 1) {
swp = offmatrix[0][1];
offmatrix[0][1] = offmatrix[0][found];
offmatrix[0][found] = swp;
if (pt->type != CL_TYPE_MSEXE) {
swp = offmatrix[pt->parts - 1][1];
offmatrix[pt->parts - 1][1] = offmatrix[pt->parts - 1][found];
offmatrix[pt->parts - 1][found] = swp;
}
}
if (pt->partno == 1 || (found && (pt->partno != pt->parts))) {
if (offmatrix[pt->partno - 1][0] == CLI_DEFAULT_AC_TRACKLEN + 1)
offmatrix[pt->partno - 1][0] = 1; /* wrap, ends up at 2 */
offmatrix[pt->partno - 1][0]++;
offmatrix[pt->partno - 1][offmatrix[pt->partno - 1][0]] = offset + matchend;
if (pt->partno == 1) /* save realoff for the first part */
offmatrix[pt->parts - 1][offmatrix[pt->partno - 1][0]] = realoff;
} else if (found && pt->partno == pt->parts) {
if (pt->type) {
if (pt->type == CL_TYPE_IGNORED && (!pt->rtype || ftype == pt->rtype))
return CL_TYPE_IGNORED;
if ((pt->type > type || pt->type >= CL_TYPE_SFX || pt->type == CL_TYPE_MSEXE) &&
(pt->rtype == CL_TYPE_ANY || ftype == pt->rtype)) {
cli_dbgmsg("Matched signature for file type %s\n", pt->virname);
type = pt->type;
if ((ftoffset != NULL) &&
((*ftoffset == NULL) || (*ftoffset)->cnt < MAX_EMBEDDED_OBJ || type == CL_TYPE_ZIPSFX) && (type >= CL_TYPE_SFX || ((ftype == CL_TYPE_MSEXE || ftype == CL_TYPE_ZIP || ftype == CL_TYPE_MSOLE2) && type == CL_TYPE_MSEXE))) {
/* FIXME: the first offset in the array is most likely the correct one but
* it may happen it is not
*/
for (j = 1; j <= CLI_DEFAULT_AC_TRACKLEN + 1 && offmatrix[0][j] != (uint32_t)-1; j++)
if (ac_addtype(ftoffset, type, offmatrix[pt->parts - 1][j], ctx))
return CL_EMEM;
}
memset(offmatrix[0], (uint32_t)-1, pt->parts * (CLI_DEFAULT_AC_TRACKLEN + 2) * sizeof(uint32_t));
for (j = 0; j < pt->parts; j++)
offmatrix[j][0] = 0;
}
} else { /* !pt->type */
if (pt->lsigid[0]) {
rc = lsig_sub_matched(root, mdata, pt->lsigid[1], pt->lsigid[2], offmatrix[pt->parts - 1][1], 1);
if (rc != CL_SUCCESS)
return rc;
ptN = ptN->next_same;
continue;
}
if (res) {
newres = (struct cli_ac_result *)malloc(sizeof(struct cli_ac_result));
if (!newres) {
cli_errmsg("cli_ac_scanbuff: Can't allocate memory for newres %lu\n", (unsigned long)sizeof(struct cli_ac_result));
return CL_EMEM;
}
newres->virname = pt->virname;
newres->customdata = pt->customdata;
newres->next = *res;
newres->offset = (off_t)offmatrix[pt->parts - 1][1];
*res = newres;
ptN = ptN->next_same;
continue;
} else {
if (ctx && SCAN_ALLMATCHES) {
ret = cli_append_virus(ctx, (const char *)pt->virname);
if (ret == CL_VIRUS) {
viruses_found = 1;
}
}
if (virname)
*virname = pt->virname;
if (customdata)
*customdata = pt->customdata;
if (!ctx || !SCAN_ALLMATCHES)
return CL_VIRUS;
ptN = ptN->next_same;
continue;
}
}
}
} else { /* old type signature */
if (pt->type) {
if (pt->type == CL_TYPE_IGNORED && (pt->rtype == CL_TYPE_ANY || ftype == pt->rtype))
return CL_TYPE_IGNORED;
if ((pt->type > type || pt->type >= CL_TYPE_SFX || pt->type == CL_TYPE_MSEXE) &&
(pt->rtype == CL_TYPE_ANY || ftype == pt->rtype)) {
cli_dbgmsg("Matched signature for file type %s at %u\n", pt->virname, realoff);
type = pt->type;
if ((ftoffset != NULL) &&
((*ftoffset == NULL) || (*ftoffset)->cnt < MAX_EMBEDDED_OBJ || type == CL_TYPE_ZIPSFX) && (type == CL_TYPE_MBR || type >= CL_TYPE_SFX || ((ftype == CL_TYPE_MSEXE || ftype == CL_TYPE_ZIP || ftype == CL_TYPE_MSOLE2) && type == CL_TYPE_MSEXE))) {
if (ac_addtype(ftoffset, type, realoff, ctx))
return CL_EMEM;
}
}
} else {
if (pt->lsigid[0]) {
rc = lsig_sub_matched(root, mdata, pt->lsigid[1], pt->lsigid[2], realoff, 0);
if (rc != CL_SUCCESS)
return rc;
ptN = ptN->next_same;
continue;
}
if (res) {
newres = (struct cli_ac_result *)malloc(sizeof(struct cli_ac_result));
if (!newres) {
cli_errmsg("cli_ac_scanbuff: Can't allocate memory for newres %lu\n", (unsigned long)sizeof(struct cli_ac_result));
return CL_EMEM;
}
newres->virname = pt->virname;
newres->customdata = pt->customdata;
newres->offset = (off_t)realoff;
newres->next = *res;
*res = newres;
ptN = ptN->next_same;
continue;
} else {
if (ctx && SCAN_ALLMATCHES) {
ret = cli_append_virus(ctx, (const char *)pt->virname);
if (ret == CL_VIRUS) {
viruses_found = 1;
}
}
if (virname)
*virname = pt->virname;
if (customdata)
*customdata = pt->customdata;
if (!ctx || !SCAN_ALLMATCHES)
return CL_VIRUS;
ptN = ptN->next_same;
continue;
}
}
}
ptN = ptN->next_same;
}
}
pattN = pattN->next;
}
}
}
if (viruses_found)
return CL_VIRUS;
return (mode & AC_SCAN_FT) ? type : CL_CLEAN;
}
static int qcompare_byte(const void *a, const void *b)
{
return *(const unsigned char *)a - *(const unsigned char *)b;
}
static int qcompare_fstr(const void *arg, const void *a, const void *b)
{
uint16_t len = *(uint16_t *)arg;
return memcmp(*(const unsigned char **)a, *(const unsigned char **)b, len);
}
/* returns if level of nesting, end set to MATCHING paren, start AFTER staring paren */
inline static size_t find_paren_end(char *hexstr, char **end)
{
size_t i;
size_t nest = 0, level = 0;
*end = NULL;
for (i = 0; i < strlen(hexstr); i++) {
if (hexstr[i] == '(') {
nest++;
level++;
} else if (hexstr[i] == ')') {
if (!level) {
*end = &hexstr[i];
break;
}
level--;
}
}
return nest;
}
/* analyzes expr, returns number of subexpr, if fixed length subexpr and longest subexpr len *
* goes to either end of string or to closing parenthesis; allowed to be unbalanced *
* counts applied to start of expr (not end, i.e. numexpr starts at 1 for the first expr */
inline static int ac_analyze_expr(char *hexstr, int *fixed_len, int *sub_len)
{
unsigned long i;
int level = 0, len = 0, numexpr = 1;
int flen, slen;
flen = 1;
slen = 0;
for (i = 0; i < strlen(hexstr); i++) {
if (hexstr[i] == '(') {
flen = 0;
level++;
} else if (hexstr[i] == ')') {
if (!level) {
if (!slen) {
slen = len;
} else if (len != slen) {
flen = 0;
if (len > slen)
slen = len;
}
break;
}
level--;
}
if (!level && hexstr[i] == '|') {
if (!slen) {
slen = len;
} else if (len != slen) {
flen = 0;
if (len > slen)
slen = len;
}
len = 0;
numexpr++;
} else {
if (hexstr[i] == '?')
flen = 0;
len++;
}
}
if (!slen) {
slen = len;
} else if (len != slen) {
flen = 0;
if (len > slen)
slen = len;
}
if (sub_len)
*sub_len = slen;
if (fixed_len)
*fixed_len = flen;
return numexpr;
}
inline static int ac_uicmp(uint16_t *a, size_t alen, uint16_t *b, size_t blen, int *wild)
{
uint16_t awild, bwild, side_wild;
size_t i, minlen = MIN(alen, blen);
side_wild = 0;
for (i = 0; i < minlen; i++) {
awild = a[i] & CLI_MATCH_WILDCARD;
bwild = b[i] & CLI_MATCH_WILDCARD;
if (awild == bwild) {
switch (awild) {
case CLI_MATCH_CHAR:
if ((a[i] & 0xff) != (b[i] & 0xff)) {
return (b[i] & 0xff) - (a[i] & 0xff);
}
break;
case CLI_MATCH_IGNORE:
break;
case CLI_MATCH_NIBBLE_HIGH:
if ((a[i] & 0xf0) != (b[i] & 0xf0)) {
return (b[i] & 0xf0) - (a[i] & 0xf0);
}
break;
case CLI_MATCH_NIBBLE_LOW:
if ((a[i] & 0x0f) != (b[i] & 0x0f)) {
return (b[i] & 0x0f) - (a[i] & 0x0f);
}
break;
default:
cli_errmsg("ac_uicmp: unhandled wildcard type\n");
return 1;
}
} else { /* not identical wildcard types */
if (awild == CLI_MATCH_CHAR) { /* b is only wild */
switch (bwild) {
case CLI_MATCH_IGNORE:
side_wild |= 2;
break;
case CLI_MATCH_NIBBLE_HIGH:
if ((a[i] & 0xf0) != (b[i] & 0xf0)) {
return (b[i] & 0xf0) - (a[i] & 0xff);
}
side_wild |= 2;
break;
case CLI_MATCH_NIBBLE_LOW:
if ((a[i] & 0x0f) != (b[i] & 0x0f)) {
return (b[i] & 0x0f) - (a[i] & 0xff);
}
side_wild |= 2;
break;
default:
cli_errmsg("ac_uicmp: unhandled wildcard type\n");
return -1;
}
} else if (bwild == CLI_MATCH_CHAR) { /* a is only wild */
switch (awild) {
case CLI_MATCH_IGNORE:
side_wild |= 1;
break;
case CLI_MATCH_NIBBLE_HIGH:
if ((a[i] & 0xf0) != (b[i] & 0xf0)) {
return (b[i] & 0xff) - (a[i] & 0xf0);
}
side_wild |= 1;
break;
case CLI_MATCH_NIBBLE_LOW:
if ((a[i] & 0x0f) != (b[i] & 0x0f)) {
return (b[i] & 0xff) - (a[i] & 0x0f);
}
side_wild |= 1;
break;
default:
cli_errmsg("ac_uicmp: unhandled wild typing\n");
return 1;
}
} else { /* not identical, both wildcards */
if (awild == CLI_MATCH_IGNORE || bwild == CLI_MATCH_IGNORE) {
if (awild == CLI_MATCH_IGNORE) {
side_wild |= 1;
} else if (bwild == CLI_MATCH_IGNORE) {
side_wild |= 2;
}
} else {
/* only high and low nibbles should be left here */
side_wild |= 3;
}
}
}
/* both sides contain a wildcard that contains the other, therefore unique by wildcards */
if (side_wild == 3)
return 1;
}
if (wild)
*wild = side_wild;
return 0;
}
/* add new generic alternate node to special */
inline static int ac_addspecial_add_alt_node(const char *subexpr, uint8_t sigopts, struct cli_ac_special *special, struct cli_matcher *root)
{
struct cli_alt_node *newnode = NULL;
struct cli_alt_node **prev = NULL;
struct cli_alt_node *ins = NULL;
uint16_t *s = NULL;
int i = 0;
int cmp = 0;
int wild = 0;
#ifndef USE_MPOOL
UNUSEDPARAM(root);
#endif
newnode = (struct cli_alt_node *)MPOOL_CALLOC(root->mempool, 1, sizeof(struct cli_alt_node));
if (!newnode) {
cli_errmsg("ac_addspecial_add_alt_node: Can't allocate new alternate node\n");
return CL_EMEM;
}
s = CLI_MPOOL_HEX2UI(root->mempool, subexpr);
if (!s) {
MPOOL_FREE(root->mempool, newnode);
return CL_EMALFDB;
}
newnode->str = s;
newnode->len = (uint16_t)strlen(subexpr) / 2;
newnode->unique = 1;
/* setting nocase match */
if (sigopts & ACPATT_OPTION_NOCASE) {
for (i = 0; i < newnode->len; ++i)
if ((newnode->str[i] & CLI_MATCH_METADATA) == CLI_MATCH_CHAR) {
newnode->str[i] = CLI_NOCASE(newnode->str[i] & 0xff);
newnode->str[i] += CLI_MATCH_NOCASE;
}
}
/* search for uniqueness, TODO: directed acyclic word graph */
prev = &((special->alt).v_str);
ins = (special->alt).v_str;
while (ins) {
cmp = ac_uicmp(ins->str, ins->len, newnode->str, newnode->len, &wild);
if (cmp == 0) {
if (newnode->len != ins->len) { /* derivative */
newnode->unique = 0;
ins->unique = 0;
} else if (wild == 0) { /* duplicate */
MPOOL_FREE(root->mempool, newnode->str);
MPOOL_FREE(root->mempool, newnode);
return CL_SUCCESS;
}
} /* TODO - possible sorting of altstr uniques and derivative groups? */
prev = &(ins->next);
ins = ins->next;
}
*prev = newnode;
newnode->next = ins;
if ((special->num == 0) || (newnode->len < special->len[0]))
special->len[0] = newnode->len;
if ((special->num == 0) || (newnode->len > special->len[1]))
special->len[1] = newnode->len;
special->num++;
return CL_SUCCESS;
}
/* recursive special handler for expanding and adding generic alternates */
static int ac_special_altexpand(char *hexpr, char *subexpr, uint16_t maxlen, int lvl, int maxlvl, uint8_t sigopts, struct cli_ac_special *special, struct cli_matcher *root)
{
int ret, scnt = 0, numexpr;
char *ept, *sexpr, *end, term;
char *fp;
ept = sexpr = hexpr;
fp = subexpr + strlen(subexpr);
numexpr = ac_analyze_expr(hexpr, NULL, NULL);
/* while there are expressions to resolve */
while (scnt < numexpr) {
scnt++;
while ((*ept != '(') && (*ept != '|') && (*ept != ')') && (*ept != '\0'))
ept++;
/* check for invalid negation */
term = *ept;
if ((*ept == '(') && (ept >= hexpr + 1)) {
if (ept[-1] == '!') {
cli_errmsg("ac_special_altexpand: Generic alternates cannot contain negations\n");
return CL_EMALFDB;
}
}
/* appended token */
*ept = 0;
if (cli_strlcat(subexpr, sexpr, maxlen) >= maxlen) {
cli_errmsg("ac_special_altexpand: Unexpected expression larger than expected\n");
return CL_EMEM;
}
*ept++ = term;
sexpr = ept;
if (term == '|') {
if (lvl == 0) {
if ((ret = ac_addspecial_add_alt_node(subexpr, sigopts, special, root)) != CL_SUCCESS)
return ret;
} else {
find_paren_end(ept, &end);
if (!end) {
cli_errmsg("ac_special_altexpand: Missing closing parenthesis\n");
return CL_EMALFDB;
}
end++;
if ((ret = ac_special_altexpand(end, subexpr, maxlen, lvl - 1, lvl, sigopts, special, root)) != CL_SUCCESS)
return ret;
}
*fp = 0;
} else if (term == ')') {
if (lvl == 0) {
cli_errmsg("ac_special_altexpand: Unexpected closing parenthesis\n");
return CL_EPARSE;
}
if ((ret = ac_special_altexpand(ept, subexpr, maxlen, lvl - 1, lvl, sigopts, special, root)) != CL_SUCCESS)
return ret;
break;
} else if (term == '(') {
int inner, found;
find_paren_end(ept, &end);
if (!end) {
cli_errmsg("ac_special_altexpand: Missing closing parenthesis\n");
return CL_EMALFDB;
}
end++;
if ((ret = ac_special_altexpand(ept, subexpr, maxlen, lvl + 1, lvl + 1, sigopts, special, root)) != CL_SUCCESS)
return ret;
/* move ept to end of current alternate expression (recursive call already populates them) */
ept = end;
inner = 0;
found = 0;
while (!found && *ept != '\0') {
switch (*ept) {
case '|':
if (!inner)
found = 1;
break;
case '(':
inner++;
break;
case ')':
inner--;
break;
}
ept++;
}
if (*ept == '|')
ept++;
sexpr = ept;
*fp = 0;
} else if (term == '\0') {
if ((ret = ac_addspecial_add_alt_node(subexpr, sigopts, special, root)) != CL_SUCCESS)
return ret;
break;
}
if (lvl != maxlvl)
return CL_SUCCESS;
}
if (scnt != numexpr) {
cli_errmsg("ac_addspecial: Mismatch in parsed and expected signature\n");
return CL_EMALFDB;
}
return CL_SUCCESS;
}
/* alternate string specials (so many specials!) */
inline static int ac_special_altstr(const char *hexpr, uint8_t sigopts, struct cli_ac_special *special, struct cli_matcher *root)
{
char *hexprcpy, *h, *c;
int i, ret, num, fixed, slen;
if (!(hexprcpy = cli_strdup(hexpr))) {
cli_errmsg("ac_special_altstr: Can't duplicate alternate expression\n");
return CL_EDUP;
}
num = ac_analyze_expr(hexprcpy, &fixed, &slen);
if (!sigopts && fixed) {
special->num = 0;
special->len[0] = special->len[1] = slen / 2;
/* single-bytes are len 2 in hex */
if (slen == 2) {
special->type = AC_SPECIAL_ALT_CHAR;
(special->alt).byte = (unsigned char *)MPOOL_MALLOC(root->mempool, num);
if (!((special->alt).byte)) {
cli_errmsg("cli_ac_special_altstr: Can't allocate newspecial->str\n");
free(hexprcpy);
return CL_EMEM;
}
} else {
special->type = AC_SPECIAL_ALT_STR_FIXED;
(special->alt).f_str = (unsigned char **)MPOOL_MALLOC(root->mempool, num * sizeof(unsigned char *));
if (!((special->alt).f_str)) {
cli_errmsg("cli_ac_special_altstr: Can't allocate newspecial->str\n");
free(hexprcpy);
return CL_EMEM;
}
}
for (i = 0; i < num; i++) {
if (num == 1) {
c = CLI_MPOOL_HEX2STR(root->mempool, hexprcpy);
} else {
if (!(h = cli_strtok(hexprcpy, i, "|"))) {
free(hexprcpy);
return CL_EMEM;
}
c = CLI_MPOOL_HEX2STR(root->mempool, h);
free(h);
}
if (!c) {
free(hexprcpy);
return CL_EMALFDB;
}
if (special->type == AC_SPECIAL_ALT_CHAR) {
(special->alt).byte[i] = (unsigned char)*c;
MPOOL_FREE(root->mempool, c);
} else {
(special->alt).f_str[i] = (unsigned char *)c;
}
special->num++;
}
/* sorting byte alternates */
if (special->num > 1 && special->type == AC_SPECIAL_ALT_CHAR)
cli_qsort((special->alt).byte, special->num, sizeof(unsigned char), qcompare_byte);
/* sorting str alternates */
if (special->num > 1 && special->type == AC_SPECIAL_ALT_STR_FIXED)
cli_qsort_r((special->alt).f_str, special->num, sizeof(unsigned char *), qcompare_fstr, &(special->len));
} else { /* generic alternates */
char *subexpr;
if (special->negative) {
cli_errmsg("ac_special_altstr: Can't apply negation operation to generic alternate strings\n");
free(hexprcpy);
return CL_EMALFDB;
}
special->type = AC_SPECIAL_ALT_STR;
/* allocate reusable subexpr */
if (!(subexpr = cli_calloc(slen + 1, sizeof(char)))) {
cli_errmsg("ac_special_altstr: Can't allocate subexpr container\n");
free(hexprcpy);
return CL_EMEM;
}
ret = ac_special_altexpand(hexprcpy, subexpr, slen + 1, 0, 0, sigopts, special, root);
free(subexpr);
free(hexprcpy);
return ret;
}
free(hexprcpy);
return CL_SUCCESS;
}
/* FIXME: clean up the code */
cl_error_t cli_ac_addsig(struct cli_matcher *root, const char *virname, const char *hexsig, uint8_t sigopts, uint32_t sigid, uint16_t parts, uint16_t partno, uint16_t rtype, uint16_t type, uint32_t mindist, uint32_t maxdist, const char *offset, const uint32_t *lsigid, unsigned int options)
{
struct cli_ac_patt *new;
char *pt, *pt2, *hex = NULL, *hexcpy = NULL;
uint16_t i, j, ppos = 0, pend, *dec, nzpos = 0;
uint8_t wprefix = 0, zprefix = 1, plen = 0, nzplen = 0;
struct cli_ac_special *newspecial, **newtable;
int ret, error = CL_SUCCESS;
char *virname_copy = NULL;
if (!root) {
cli_errmsg("cli_ac_addsig: root == NULL\n");
return CL_ENULLARG;
}
if (strlen(hexsig) / 2 < root->ac_mindepth) {
cli_errmsg("cli_ac_addsig: Signature for %s is too short\n", virname);
return CL_EMALFDB;
}
if ((new = (struct cli_ac_patt *)MPOOL_CALLOC(root->mempool, 1, sizeof(struct cli_ac_patt))) == NULL)
return CL_EMEM;
new->rtype = rtype;
new->type = type;
new->sigid = sigid;
new->parts = parts;
new->partno = partno;
new->mindist = mindist;
new->maxdist = maxdist;
new->customdata = NULL;
new->ch[0] |= CLI_MATCH_IGNORE;
new->ch[1] |= CLI_MATCH_IGNORE;
if (lsigid) {
new->lsigid[0] = 1;
memcpy(&new->lsigid[1], lsigid, 2 * sizeof(uint32_t));
}
if (strchr(hexsig, '[')) {
if (!(hexcpy = cli_strdup(hexsig))) {
MPOOL_FREE(root->mempool, new);
return CL_EMEM;
}
hex = hexcpy;
for (i = 0; i < 2; i++) {
unsigned int n, n1, n2;
if (!(pt = strchr(hex, '[')))
break;
*pt++ = 0;
if (!(pt2 = strchr(pt, ']'))) {
cli_dbgmsg("cli_ac_addsig: missing closing square bracket\n");
error = CL_EMALFDB;
break;
}
*pt2++ = 0;
n = sscanf(pt, "%u-%u", &n1, &n2);
if (n == 1) {
n2 = n1;
} else if (n != 2) {
cli_dbgmsg("cli_ac_addsig: incorrect range inside square brackets\n");
error = CL_EMALFDB;
break;
}
if ((n1 > n2) || (n2 > AC_CH_MAXDIST)) {
cli_dbgmsg("cli_ac_addsig: incorrect range inside square brackets\n");
error = CL_EMALFDB;
break;
}
if (strlen(hex) == 2) {
if (i) {
error = CL_EMALFDB;
break;
}
dec = cli_hex2ui(hex);
if (!dec) {
error = CL_EMALFDB;
break;
}
if ((sigopts & ACPATT_OPTION_NOCASE) && ((*dec & CLI_MATCH_METADATA) == CLI_MATCH_CHAR))
new->ch[i] = CLI_NOCASE(*dec) | CLI_MATCH_NOCASE;
else
new->ch[i] = *dec;
free(dec);
new->ch_mindist[i] = n1;
new->ch_maxdist[i] = n2;
hex = pt2;
} else if (strlen(pt2) == 2) {
i = 1;
dec = cli_hex2ui(pt2);
if (!dec) {
error = CL_EMALFDB;
break;
}
if ((sigopts & ACPATT_OPTION_NOCASE) && ((*dec & CLI_MATCH_METADATA) == CLI_MATCH_CHAR))
new->ch[i] = CLI_NOCASE(*dec) | CLI_MATCH_NOCASE;
else
new->ch[i] = *dec;
free(dec);
new->ch_mindist[i] = n1;
new->ch_maxdist[i] = n2;
} else {
error = CL_EMALFDB;
break;
}
}
if (error) {
free(hexcpy);
MPOOL_FREE(root->mempool, new);
return error;
}
hex = cli_strdup(hex);
free(hexcpy);
if (!hex) {
MPOOL_FREE(root->mempool, new);
return CL_EMEM;
}
}
if (strchr(hexsig, '(')) {
char *hexnew, *start;
size_t nest;
size_t hexnewsz;
if (hex) {
hexcpy = hex;
} else if (!(hexcpy = cli_strdup(hexsig))) {
MPOOL_FREE(root->mempool, new);
return CL_EMEM;
}
hexnewsz = strlen(hexsig) + 1;
if (!(hexnew = (char *)cli_calloc(1, hexnewsz))) {
MPOOL_FREE(root->mempool, new);
free(hexcpy);
return CL_EMEM;
}
start = pt = hexcpy;
while ((pt = strchr(start, '('))) {
*pt++ = 0;
if (!start) {
error = CL_EMALFDB;
break;
}
newspecial = (struct cli_ac_special *)MPOOL_CALLOC(root->mempool, 1, sizeof(struct cli_ac_special));
if (!newspecial) {
cli_errmsg("cli_ac_addsig: Can't allocate newspecial\n");
error = CL_EMEM;
break;
}
if (pt >= hexcpy + 2) {
if (pt[-2] == '!') {
newspecial->negative = 1;
pt[-2] = 0;
}
}
cli_strlcat(hexnew, start, hexnewsz);
nest = find_paren_end(pt, &start);
if (!start) {
cli_errmsg("cli_ac_addsig: Missing closing parenthesis\n");
MPOOL_FREE(root->mempool, newspecial);
error = CL_EMALFDB;
break;
}
*start++ = 0;
if (!strlen(pt)) {
cli_errmsg("cli_ac_addsig: Empty block\n");
MPOOL_FREE(root->mempool, newspecial);
error = CL_EMALFDB;
break;
}
if (nest > ACPATT_ALTN_MAXNEST) {
cli_errmsg("ac_addspecial: Expression exceeds maximum alternate nesting limit\n");
MPOOL_FREE(root->mempool, newspecial);
error = CL_EMALFDB;
break;
}
/*
* Detect special character classes
* - (B) word boundary
* - (L) CR, CRLF line boundaries
* - (W) Non-alphanumeric character
*
* For more details: https://docs.clamav.net/manual/Signatures/BodySignatureFormat.html#character-classes
*/
if (!strcmp(pt, "B")) {
if (!*start) {
new->boundary |= AC_BOUNDARY_RIGHT;
if (newspecial->negative)
new->boundary |= AC_BOUNDARY_RIGHT_NEGATIVE;
MPOOL_FREE(root->mempool, newspecial);
continue;
} else if (pt - 1 == hexcpy) {
new->boundary |= AC_BOUNDARY_LEFT;
if (newspecial->negative)
new->boundary |= AC_BOUNDARY_LEFT_NEGATIVE;
MPOOL_FREE(root->mempool, newspecial);
continue;
}
} else if (!strcmp(pt, "L")) {
if (!*start) {
new->boundary |= AC_LINE_MARKER_RIGHT;
if (newspecial->negative)
new->boundary |= AC_LINE_MARKER_RIGHT_NEGATIVE;
MPOOL_FREE(root->mempool, newspecial);
continue;
} else if (pt - 1 == hexcpy) {
new->boundary |= AC_LINE_MARKER_LEFT;
if (newspecial->negative)
new->boundary |= AC_LINE_MARKER_LEFT_NEGATIVE;
MPOOL_FREE(root->mempool, newspecial);
continue;
}
} else if (!strcmp(pt, "W")) {
if (!*start) {
new->boundary |= AC_WORD_MARKER_RIGHT;
if (newspecial->negative)
new->boundary |= AC_WORD_MARKER_RIGHT_NEGATIVE;
MPOOL_FREE(root->mempool, newspecial);
continue;
} else if (pt - 1 == hexcpy) {
new->boundary |= AC_WORD_MARKER_LEFT;
if (newspecial->negative)
new->boundary |= AC_WORD_MARKER_LEFT_NEGATIVE;
MPOOL_FREE(root->mempool, newspecial);
continue;
}
}
cli_strlcat(hexnew, "()", hexnewsz);
new->special++;
newtable = (struct cli_ac_special **)MPOOL_REALLOC(root->mempool, new->special_table, new->special * sizeof(struct cli_ac_special *));
if (!newtable) {
new->special--;
MPOOL_FREE(root->mempool, newspecial);
cli_errmsg("cli_ac_addsig: Can't realloc new->special_table\n");
error = CL_EMEM;
break;
}
newtable[new->special - 1] = newspecial;
new->special_table = newtable;
if (!strcmp(pt, "B")) {
newspecial->type = AC_SPECIAL_BOUNDARY;
} else if (!strcmp(pt, "L")) {
newspecial->type = AC_SPECIAL_LINE_MARKER;
} else if (!strcmp(pt, "W")) {
newspecial->type = AC_SPECIAL_WORD_MARKER;
} else {
if ((ret = ac_special_altstr(pt, sigopts, newspecial, root)) != CL_SUCCESS) {
error = ret;
break;
}
}
}
if (start)
cli_strlcat(hexnew, start, hexnewsz);
hex = hexnew;
free(hexcpy);
if (error) {
free(hex);
if (new->special) {
mpool_ac_free_special(root->mempool, new);
}
MPOOL_FREE(root->mempool, new);
return error;
}
}
/*
* Convert the hex string pattern to a uint16_t* pattern (flags + byte) patterns.
*/
new->pattern = CLI_MPOOL_HEX2UI(root->mempool, hex ? hex : hexsig);
if (new->pattern == NULL) {
if (new->special)
mpool_ac_free_special(root->mempool, new);
MPOOL_FREE(root->mempool, new);
free(hex);
return CL_EMALFDB;
}
new->length[0] = (uint16_t)strlen(hex ? hex : hexsig) / 2;
if (new->length[0] < root->ac_mindepth) {
cli_errmsg("cli_ac_addsig: Subpattern in signature is shorter than the minimum depth of the AC trie. (%u < %u)\n", new->length[0], root->ac_mindepth);
if (new->special)
mpool_ac_free_special(root->mempool, new);
MPOOL_FREE(root->mempool, new->pattern);
MPOOL_FREE(root->mempool, new);
free(hex);
return CL_EMALFDB;
}
for (i = 0, j = 0; i < new->length[0]; i++) {
if ((new->pattern[i] & CLI_MATCH_METADATA) == CLI_MATCH_SPECIAL) {
new->length[1] += new->special_table[j]->len[0];
new->length[2] += new->special_table[j]->len[1];
j++;
} else {
new->length[1]++;
new->length[2]++;
}
}
free(hex);
new->sigopts = sigopts;
/* setting nocase match */
if (sigopts & ACPATT_OPTION_NOCASE) {
for (i = 0; i < new->length[0]; i++)
if ((new->pattern[i] & CLI_MATCH_METADATA) == CLI_MATCH_CHAR) {
new->pattern[i] = CLI_NOCASE(new->pattern[i] & 0xff);
new->pattern[i] += CLI_MATCH_NOCASE;
}
}
/* TODO - sigopts affect on filters? */
if (root->filter) {
/* so that we can show meaningful messages */
new->virname = (char *)virname;
if (filter_add_acpatt(root->filter, new) == -1) {
cli_warnmsg("cli_ac_addsig: cannot use filter for trie\n");
MPOOL_FREE(root->mempool, root->filter);
root->filter = NULL;
}
/* TODO: should this affect maxpatlen? */
}
/*
* Check beginning bytes of the pattern up to the max-depth of the AC trie to see if:
* a. it contains a wildcard, or
* b. the bytes are all zeroes.
*
* If it does, we can try to shift the start of the pattern the right, have those beginning
* bytes be a "prefix" which gets backwards-matched after the AC match.
* This happens in the call to ac_backward_match_branch() in ac_forward_match_branch()
*/
for (i = 0; i < root->ac_maxdepth && i < new->length[0]; i++) {
if (new->pattern[i] & CLI_MATCH_WILDCARD) {
wprefix = 1;
break;
}
if (zprefix && 0 != new->pattern[i]) {
zprefix = 0;
}
}
if (wprefix || zprefix) {
/*
* This pattern has a wildcard in the first few bytes or starts with some zeroes.
* We'll try to shift the start of the pattern right a bit to find a static subpattern to use for the bytes that go in the A-C trie.
*/
// If needed, we can shift the start of the pattern that goes in the A-C Trie right up to the pattern length minus min-depth bytes
// The original starting bytes will become a "prefix" that gets backward-matched.
pend = new->length[0] - root->ac_mindepth + 1;
// Search for static bytes to start the pattern in the A-C trie that starts within original min-depth, and of a length up to max-depth.
for (i = 0; i < pend; i++) {
for (j = i; j < i + root->ac_maxdepth && j < new->length[0]; j++) {
if (new->pattern[j] & CLI_MATCH_WILDCARD) {
// Found a wildcard. Shift the pattern start right a byte, relegating this byte to the "prefix"
break;
}
// This byte is a contender for the start of the pattern.
// Record the start + length of the shifted prefix.
if (j - i + 1 >= plen) {
plen = j - i + 1;
ppos = i;
}
// Check if the starting bytes at this offset are both non-zero. If they are, then that's even better.
if ((0 != new->pattern[ppos]) ||
((new->length[0] > ppos + 1) && (0 != new->pattern[ppos + 1]))) {
// At least one of the first two bytes is non-zero which would be better than starting with two zeroes.
if (plen >= root->ac_maxdepth) {
// But... we hit max-depth, so nevermind. Let's stop searching.
break;
}
// Save off the position and length so we can roll back to it later, if needed.
if (plen >= root->ac_mindepth && plen > nzplen) {
// We've found a longer sequence of non-zero bytes we could use for the AC pattern starting position.
// Store off the length and position of this starting position with the non-zero bytes, in case we want to roll back to it.
nzplen = plen;
nzpos = ppos;
}
}
}
if (plen >= root->ac_maxdepth && (0 != new->pattern[ppos] || 0 != new->pattern[ppos + 1])) {
break;
}
}
if ((0 != nzplen) &&
(new->length[0] > ppos + 1) &&
(0 == new->pattern[ppos]) &&
(0 == new->pattern[ppos + 1])) {
// The latest shifted position starts with two zeroes.
// We found a valid static pattern earlier that doesn't start with two zeroes.
// Let's roll back a little bit to use that instead.
plen = nzplen;
ppos = nzpos;
}
if (plen < root->ac_mindepth) {
cli_errmsg("cli_ac_addsig: Can't find a static subpattern of length %u\n", root->ac_mindepth);
mpool_ac_free_special(root->mempool, new);
MPOOL_FREE(root->mempool, new->pattern);
MPOOL_FREE(root->mempool, new);
return CL_EMALFDB;
}
// Store those intial bytes as the pattern "prefix" (the stuff before what goes in the AC Trie)
new->prefix = new->pattern;
// The "prefix" length is the number of bytes before the starting position of the pattern that goes in the AC Trie.
new->prefix_length[0] = ppos;
for (i = 0, j = 0; i < new->prefix_length[0]; i++) {
if ((new->prefix[i] & CLI_MATCH_WILDCARD) == CLI_MATCH_SPECIAL)
new->special_pattern++;
if ((new->prefix[i] & CLI_MATCH_METADATA) == CLI_MATCH_SPECIAL) {
new->prefix_length[1] += new->special_table[j]->len[0];
new->prefix_length[2] += new->special_table[j]->len[1];
j++;
} else {
new->prefix_length[1]++;
new->prefix_length[2]++;
}
}
// Update the pattern to start at the shifted position with the static bytes.
new->pattern = &new->prefix[ppos];
// And update the pattern length to remove the prefix bytes.
new->length[0] -= new->prefix_length[0];
new->length[1] -= new->prefix_length[1];
new->length[2] -= new->prefix_length[2];
}
if (new->length[2] + new->prefix_length[2] > root->maxpatlen) {
// This is the longest pattern we've stored. Update our max-pattern-length record
root->maxpatlen = new->length[2] + new->prefix_length[2];
}
if (0 == new->lsigid[0]) {
/* For logical signatures, we already recorded the virname in the lsig table entry.
* For other signature types, continue to store a copy of the virname in each ac_pattern struct.
*
* TODO: Don't make a copy of the virname for every ac pattern,
* because that makes for multipel copies every time a signature has wildcards.
*/
virname_copy = CLI_MPOOL_VIRNAME(root->mempool, virname, options & CL_DB_OFFICIAL);
if (NULL == virname_copy) {
MPOOL_FREE(root->mempool, new->prefix ? new->prefix : new->pattern);
mpool_ac_free_special(root->mempool, new);
MPOOL_FREE(root->mempool, new);
return CL_EMEM;
}
new->virname = virname_copy;
}
ret = cli_caloff(offset, NULL, root->type, new->offdata, &new->offset_min, &new->offset_max);
if (ret != CL_SUCCESS) {
MPOOL_FREE(root->mempool, new->prefix ? new->prefix : new->pattern);
mpool_ac_free_special(root->mempool, new);
if (virname_copy) {
MPOOL_FREE(root->mempool, virname_copy);
}
MPOOL_FREE(root->mempool, new);
return ret;
}
if ((ret = cli_ac_addpatt(root, new))) {
MPOOL_FREE(root->mempool, new->prefix ? new->prefix : new->pattern);
if (virname_copy) {
MPOOL_FREE(root->mempool, virname_copy);
}
mpool_ac_free_special(root->mempool, new);
MPOOL_FREE(root->mempool, new);
return ret;
}
if ((new->offdata[0] != CLI_OFF_ANY) &&
(new->offdata[0] != CLI_OFF_ABSOLUTE) &&
(new->offdata[0] != CLI_OFF_MACRO)) {
root->ac_reloff = (struct cli_ac_patt **)MPOOL_REALLOC2(root->mempool, root->ac_reloff, (root->ac_reloff_num + 1) * sizeof(struct cli_ac_patt *));
if (!root->ac_reloff) {
cli_errmsg("cli_ac_addsig: Can't allocate memory for root->ac_reloff\n");
return CL_EMEM;
}
root->ac_reloff[root->ac_reloff_num] = new;
new->offset_min = root->ac_reloff_num * 2;
new->offset_max = new->offset_min + 1;
root->ac_reloff_num++;
}
return CL_SUCCESS;
}
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