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ClamAV is an open source (GPLv2) anti-virus toolkit.
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clamav/libclamav/matcher-ac.c

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/*
* Copyright (C) 2007-2009 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 "cltypes.h"
#include "str.h"
#include "readdb.h"
#include "default.h"
#include "mpool.h"
int cli_ac_addpatt(struct cli_matcher *root, struct cli_ac_patt *pattern)
{
struct cli_ac_node *pt, *next;
struct cli_ac_patt *ph;
void *newtable;
struct cli_ac_alt *a1, *a2;
uint8_t i, match;
uint16_t len = MIN(root->ac_maxdepth, pattern->length);
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;
}
pt = root->ac_root;
for(i = 0; i < len; i++) {
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;
}
}
next = pt->trans[(unsigned char) (pattern->pattern[i] & 0xff)];
if(!next) {
next = (struct cli_ac_node *) mpool_calloc(root->mempool, 1, sizeof(struct cli_ac_node));
if(!next) {
cli_errmsg("cli_ac_addpatt: Can't allocate memory for AC node\n");
return CL_EMEM;
}
if(i != len - 1) {
next->trans = (struct cli_ac_node **) mpool_calloc(root->mempool, 256, sizeof(struct cli_ac_node *));
if(!next->trans) {
cli_errmsg("cli_ac_addpatt: Can't allocate memory for next->trans\n");
mpool_free(root->mempool, next);
return CL_EMEM;
}
}
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(next->trans)
mpool_free(root->mempool, next->trans);
mpool_free(root->mempool, next);
return CL_EMEM;
}
root->ac_nodetable = (struct cli_ac_node **) newtable;
root->ac_nodetable[root->ac_nodes - 1] = next;
pt->trans[(unsigned char) (pattern->pattern[i] & 0xff)] = next;
}
pt = next;
}
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 = (struct cli_ac_patt **) newtable;
root->ac_pattable[root->ac_patterns - 1] = pattern;
pattern->depth = i;
ph = pt->list;
while(ph) {
if((ph->length == pattern->length) && (ph->prefix_length == pattern->prefix_length) && (ph->ch[0] == pattern->ch[0]) && (ph->ch[1] == pattern->ch[1])) {
if(!memcmp(ph->pattern, pattern->pattern, ph->length * sizeof(uint16_t)) && !memcmp(ph->prefix, pattern->prefix, ph->prefix_length * sizeof(uint16_t))) {
if(!ph->alt && !pattern->alt) {
match = 1;
} else if(ph->alt == pattern->alt) {
match = 1;
for(i = 0; i < ph->alt; i++) {
a1 = ph->alttable[i];
a2 = pattern->alttable[i];
if(a1->num != a2->num) {
match = 0;
break;
}
if(a1->chmode != a2->chmode) {
match = 0;
break;
} else if(a1->chmode) {
if(memcmp(a1->str, a2->str, a1->num)) {
match = 0;
break;
}
} else {
while(a1 && a2) {
if((a1->len != a2->len) || memcmp(a1->str, a2->str, a1->len))
break;
a1 = a1->next;
a2 = a2->next;
}
if(a1 || a2) {
match = 0;
break;
}
}
}
} else {
match = 0;
}
if(match) {
pattern->next_same = ph->next_same;
ph->next_same = pattern;
return CL_SUCCESS;
}
}
}
ph = ph->next;
}
pattern->next = pt->list;
pt->list = pattern;
return CL_SUCCESS;
}
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;
struct cli_ac_patt *patt;
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(IS_LEAF(failtarget))
failtarget = failtarget->fail;
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(child->list) {
patt = child->list;
while(patt->next)
patt = patt->next;
patt->next = child->fail->list;
} else {
child->list = child->fail->list;
}
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) {
struct cli_ac_node *failtarget = node->fail;
while(IS_LEAF(failtarget) || !failtarget->trans[i])
failtarget = failtarget->fail;
node->trans[i] = failtarget->trans[i];
} else {
if((ret = bfs_enqueue(&bfs, &bfs_last, child)) != 0)
return ret;
}
}
}
return CL_SUCCESS;
}
int 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;
}
return ac_maketrans(root);
}
int cli_ac_init(struct cli_matcher *root, uint8_t mindepth, uint8_t maxdepth)
{
#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;
return CL_SUCCESS;
}
#ifdef USE_MPOOL
#define mpool_ac_free_alt(a, b) ac_free_alt(a, b)
static void ac_free_alt(mpool_t *mempool, struct cli_ac_patt *p)
#else
#define mpool_ac_free_alt(a, b) ac_free_alt(b)
static void ac_free_alt(struct cli_ac_patt *p)
#endif
{
uint16_t i;
struct cli_ac_alt *a1, *a2;
if(!p->alt)
return;
for(i = 0; i < p->alt; i++) {
a1 = p->alttable[i];
while(a1) {
a2 = a1;
a1 = a1->next;
if(a2->str)
mpool_free(mempool, a2->str);
mpool_free(mempool, a2);
}
}
mpool_free(mempool, p->alttable);
}
void cli_ac_free(struct cli_matcher *root)
{
uint32_t i;
struct cli_ac_patt *patt;
for(i = 0; i < root->ac_patterns; i++) {
patt = root->ac_pattable[i];
mpool_free(root->mempool, patt->prefix ? patt->prefix : patt->pattern);
mpool_free(root->mempool, patt->virname);
if(patt->alt)
mpool_ac_free_alt(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_nodes; i++) {
if(!IS_LEAF(root->ac_nodetable[i]))
mpool_free(root->mempool, root->ac_nodetable[i]->trans);
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);
}
}
/*
* 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--;
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;
}
}
}
/*
* FIXME: the current support for string alternatives uses a brute-force
* approach and doesn't perform any kind of verification and
* backtracking. This may easily lead to false negatives, eg. when
* an alternative contains strings of different lengths and
* more than one of them can match at the current position.
*/
#define AC_MATCH_CHAR(p,b) \
switch(wc = p & CLI_MATCH_WILDCARD) { \
case CLI_MATCH_CHAR: \
if((unsigned char) p != b) \
match = 0; \
break; \
\
case CLI_MATCH_IGNORE: \
break; \
\
case CLI_MATCH_ALTERNATIVE: \
match = 0; \
alt = pattern->alttable[altcnt]; \
if(alt->chmode) { \
for(j = 0; j < alt->num; j++) { \
if(alt->str[j] == b) { \
match = 1; \
break; \
} \
} \
} else { \
while(alt) { \
if(bp + alt->len <= length) { \
if(!memcmp(&buffer[bp], alt->str, alt->len)) { \
match = 1; \
bp += alt->len - 1; \
break; \
} \
} \
alt = alt->next; \
} \
} \
altcnt++; \
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 wildcard 0x%x\n", wc); \
match = 0; \
}
inline static int ac_findmatch(const unsigned char *buffer, uint32_t offset, uint32_t length, const struct cli_ac_patt *pattern, uint32_t *end)
{
uint32_t bp, match;
uint16_t wc, i, j, altcnt = pattern->alt_pattern;
struct cli_ac_alt *alt;
if((offset + pattern->length > length) || (pattern->prefix_length > offset))
return 0;
bp = offset + pattern->depth;
match = 1;
for(i = pattern->depth; i < pattern->length && bp < length; i++) {
AC_MATCH_CHAR(pattern->pattern[i],buffer[bp]);
if(!match)
return 0;
bp++;
}
*end = bp;
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]);
if(match)
break;
bp++;
}
if(!match)
return 0;
}
if(pattern->prefix) {
altcnt = 0;
bp = offset - pattern->prefix_length;
match = 1;
for(i = 0; i < pattern->prefix_length; i++) {
AC_MATCH_CHAR(pattern->prefix[i],buffer[bp]);
if(!match)
return 0;
bp++;
}
}
if(!(pattern->ch[0] & CLI_MATCH_IGNORE)) {
bp = offset - pattern->prefix_length;
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]);
if(match)
break;
if(!bp)
return 0;
else
bp--;
}
if(!match)
return 0;
}
return 1;
}
int cli_ac_initdata(struct cli_ac_data *data, uint32_t partsigs, uint32_t lsigs, uint32_t reloffsigs, uint8_t tracklen)
{
unsigned int i;
if(!data) {
cli_errmsg("cli_ac_init: data == NULL\n");
return CL_ENULLARG;
}
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 = (int32_t ***) cli_calloc(partsigs, sizeof(int32_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;
}
return CL_SUCCESS;
}
int cli_ac_caloff(const struct cli_matcher *root, struct cli_ac_data *data, struct F_MAP *map)
{
int ret;
unsigned int i;
struct cli_ac_patt *patt;
struct cli_target_info info;
struct stat sb;
if(map) {
memset(&info, 0, sizeof(info));
info.fsize = map->len;
}
for(i = 0; i < root->ac_reloff_num; i++) {
patt = root->ac_reloff[i];
if(!map) {
data->offset[patt->offset_min] = CLI_OFF_NONE;
} else if((ret = cli_caloff(NULL, &info, map, 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);
if(info.exeinfo.section)
free(info.exeinfo.section);
return ret;
} else if(data->offset[patt->offset_min] + patt->length > info.fsize) {
data->offset[patt->offset_min] = CLI_OFF_NONE;
}
}
if(map && info.exeinfo.section)
free(info.exeinfo.section);
return CL_SUCCESS;
}
void cli_ac_freedata(struct cli_ac_data *data)
{
uint32_t i;
if(data && 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->partsigs = 0;
}
if(data && data->lsigs) {
free(data->lsigcnt[0]);
free(data->lsigcnt);
data->lsigs = 0;
}
if(data && data->reloffsigs) {
free(data->offset);
data->reloffsigs = 0;
}
}
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;
}
int 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, const cli_ctx *ctx)
{
struct cli_ac_node *current;
struct cli_ac_patt *patt, *pt;
uint32_t i, bp, realoff, matchend;
uint16_t j;
int32_t **offmatrix;
uint8_t found;
int type = CL_CLEAN;
struct cli_ac_result *newres;
if(!root->ac_root)
return CL_CLEAN;
if(!mdata) {
cli_errmsg("cli_ac_scanbuff: mdata == NULL\n");
return CL_ENULLARG;
}
current = root->ac_root;
for(i = 0; i < length; i++) {
if(IS_LEAF(current))
current = current->fail;
current = current->trans[buffer[i]];
if(IS_FINAL(current)) {
patt = current->list;
while(patt) {
bp = i + 1 - patt->depth;
if(!patt->next_same && (patt->offset_min != CLI_OFF_ANY) && (!patt->sigid || patt->partno == 1)) {
if(patt->offset_min == CLI_OFF_NONE) {
patt = patt->next;
continue;
}
realoff = offset + bp - patt->prefix_length;
if(patt->offdata[0] == CLI_OFF_ABSOLUTE) {
if(patt->offset_max < realoff || patt->offset_min > realoff) {
patt = patt->next;
continue;
}
} else {
if(mdata->offset[patt->offset_min] == CLI_OFF_NONE || mdata->offset[patt->offset_max] < realoff || mdata->offset[patt->offset_min] > realoff) {
patt = patt->next;
continue;
}
}
}
pt = patt;
if(ac_findmatch(buffer, bp, length, patt, &matchend)) {
while(pt) {
if((pt->type && !(mode & AC_SCAN_FT)) || (!pt->type && !(mode & AC_SCAN_VIR))) {
pt = pt->next_same;
continue;
}
realoff = offset + bp - pt->prefix_length;
if(pt->offset_min != CLI_OFF_ANY && (!pt->sigid || pt->partno == 1)) {
if(pt->offset_min == CLI_OFF_NONE) {
pt = pt->next_same;
continue;
}
if(pt->offdata[0] == CLI_OFF_ABSOLUTE) {
if(pt->offset_max < realoff || pt->offset_min > realoff) {
pt = pt->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) {
pt = pt->next_same;
continue;
}
}
}
if(pt->sigid) { /* it's a partial signature */
if(pt->partno != 1 && (!mdata->offmatrix[pt->sigid - 1] || !mdata->offmatrix[pt->sigid - 1][pt->partno - 2][0])) {
pt = pt->next_same;
continue;
}
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 + 1) * sizeof(int32_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], -1, pt->parts * (CLI_DEFAULT_AC_TRACKLEN + 1) * sizeof(int32_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 + 1);
mdata->offmatrix[pt->sigid - 1][j][0] = 0;
}
}
offmatrix = mdata->offmatrix[pt->sigid - 1];
if(pt->partno != 1) {
found = 0;
for(j = 1; j <= CLI_DEFAULT_AC_TRACKLEN && offmatrix[pt->partno - 2][j] != -1; j++) {
found = 1;
if(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 == 1 || (found && (pt->partno != pt->parts))) {
offmatrix[pt->partno - 1][0] %= CLI_DEFAULT_AC_TRACKLEN;
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 || ftype == pt->rtype)) {
cli_dbgmsg("Matched signature for file type %s\n", pt->virname);
type = pt->type;
if(ftoffset && (!*ftoffset || (*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: we don't know which offset of the first part is the correct one */
for(j = 1; j <= CLI_DEFAULT_AC_TRACKLEN && offmatrix[0][j] != -1; j++)
if(ac_addtype(ftoffset, type, offmatrix[pt->parts - 1][j], ctx))
return CL_EMEM;
}
memset(offmatrix[0], -1, pt->parts * (CLI_DEFAULT_AC_TRACKLEN + 1) * sizeof(int32_t));
for(j = 0; j < pt->parts; j++)
offmatrix[j][0] = 0;
}
} else { /* !pt->type */
if(pt->lsigid[0]) {
mdata->lsigcnt[pt->lsigid[1]][pt->lsigid[2]]++;
pt = pt->next;
continue;
}
if(res) {
newres = (struct cli_ac_result *) malloc(sizeof(struct cli_ac_result));
if(!newres)
return CL_EMEM;
newres->virname = pt->virname;
newres->customdata = pt->customdata;
newres->next = *res;
*res = newres;
pt = pt->next;
continue;
} else {
if(virname)
*virname = pt->virname;
if(customdata)
*customdata = pt->customdata;
return CL_VIRUS;
}
}
}
} else { /* old type signature */
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 || ftype == pt->rtype)) {
cli_dbgmsg("Matched signature for file type %s at %u\n", pt->virname, realoff);
type = pt->type;
if(ftoffset && (!*ftoffset || (*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))) {
if(ac_addtype(ftoffset, type, realoff, ctx))
return CL_EMEM;
}
}
} else {
if(pt->lsigid[0]) {
mdata->lsigcnt[pt->lsigid[1]][pt->lsigid[2]]++;
pt = pt->next;
continue;
}
if(res) {
newres = (struct cli_ac_result *) malloc(sizeof(struct cli_ac_result));
if(!newres)
return CL_EMEM;
newres->virname = pt->virname;
newres->customdata = pt->customdata;
newres->next = *res;
*res = newres;
pt = pt->next;
continue;
} else {
if(virname)
*virname = pt->virname;
if(customdata)
*customdata = pt->customdata;
return CL_VIRUS;
}
}
}
pt = pt->next_same;
}
}
patt = patt->next;
}
}
}
return (mode & AC_SCAN_FT) ? type : CL_CLEAN;
}
/* FIXME: clean up the code */
int cli_ac_addsig(struct cli_matcher *root, const char *virname, const char *hexsig, 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_alt *newalt, *altpt, **newtable;
int ret, error = CL_SUCCESS;
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 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;
if(sscanf(pt, "%u-%u", &n1, &n2) != 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;
}
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;
}
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, *h, *c;
if(hex) {
hexcpy = hex;
} else if(!(hexcpy = cli_strdup(hexsig))) {
mpool_free(root->mempool, new);
return CL_EMEM;
}
if(!(hexnew = (char *) cli_calloc(strlen(hexsig) + 1, 1))) {
free(new);
free(hexcpy);
return CL_EMEM;
}
start = pt = hexcpy;
while((pt = strchr(start, '('))) {
*pt++ = 0;
if(!start) {
error = CL_EMALFDB;
break;
}
strcat(hexnew, start);
strcat(hexnew, "()");
if(!(start = strchr(pt, ')'))) {
error = CL_EMALFDB;
break;
}
*start++ = 0;
newalt = (struct cli_ac_alt *) mpool_calloc(root->mempool, 1, sizeof(struct cli_ac_alt));
if(!newalt) {
cli_errmsg("cli_ac_addsig: Can't allocate newalt\n");
error = CL_EMEM;
break;
}
new->alt++;
newtable = (struct cli_ac_alt **) mpool_realloc(root->mempool, new->alttable, new->alt * sizeof(struct cli_ac_alt *));
if(!newtable) {
new->alt--;
mpool_free(root->mempool, newalt);
cli_errmsg("cli_ac_addsig: Can't realloc new->alttable\n");
error = CL_EMEM;
break;
}
newtable[new->alt - 1] = newalt;
new->alttable = newtable;
for(i = 0; i < strlen(pt); i++)
if(pt[i] == '|')
newalt->num++;
if(!newalt->num) {
error = CL_EMALFDB;
break;
} else
newalt->num++;
if(3 * newalt->num - 1 == (uint16_t) strlen(pt)) {
newalt->chmode = 1;
newalt->str = (unsigned char *) mpool_malloc(root->mempool, newalt->num);
if(!newalt->str) {
cli_errmsg("cli_ac_addsig: Can't allocate newalt->str\n");
error = CL_EMEM;
break;
}
}
for(i = 0; i < newalt->num; i++) {
if(!(h = cli_strtok(pt, i, "|"))) {
error = CL_EMALFDB;
break;
}
if(!(c = cli_mpool_hex2str(root->mempool, h))) {
free(h);
error = CL_EMALFDB;
break;
}
if(newalt->chmode) {
newalt->str[i] = *c;
mpool_free(root->mempool, c);
} else {
if(i) {
altpt = newalt;
while(altpt->next)
altpt = altpt->next;
altpt->next = (struct cli_ac_alt *) mpool_calloc(root->mempool, 1, sizeof(struct cli_ac_alt));
if(!altpt->next) {
cli_errmsg("cli_ac_addsig: Can't allocate altpt->next\n");
error = CL_EMEM;
free(c);
free(h);
break;
}
altpt->next->str = (unsigned char *) c;
altpt->next->len = strlen(h) / 2;
} else {
newalt->str = (unsigned char *) c;
newalt->len = strlen(h) / 2;
}
}
free(h);
}
if(error)
break;
}
if(start)
strcat(hexnew, start);
hex = hexnew;
free(hexcpy);
if(error) {
if(new->alt) {
free(hex);
mpool_ac_free_alt(root->mempool, new);
}
mpool_free(root->mempool, new);
return error;
}
}
new->pattern = cli_mpool_hex2ui(root->mempool, hex ? hex : hexsig);
if(new->pattern == NULL) {
if(new->alt)
mpool_ac_free_alt(root->mempool, new);
mpool_free(root->mempool, new);
free(hex);
return CL_EMALFDB;
}
new->length = strlen(hex ? hex : hexsig) / 2;
free(hex);
for(i = 0; i < root->ac_maxdepth && i < new->length; i++) {
if(new->pattern[i] & CLI_MATCH_WILDCARD) {
wprefix = 1;
break;
}
if(zprefix && new->pattern[i])
zprefix = 0;
}
if(wprefix || zprefix) {
pend = new->length - root->ac_mindepth + 1;
for(i = 0; i < pend; i++) {
for(j = i; j < i + root->ac_maxdepth && j < new->length; j++) {
if(new->pattern[j] & CLI_MATCH_WILDCARD) {
break;
} else {
if(j - i + 1 >= plen) {
plen = j - i + 1;
ppos = i;
}
}
if(new->pattern[ppos] || new->pattern[ppos + 1]) {
if(plen >= root->ac_maxdepth) {
break;
} else if(plen >= root->ac_mindepth && plen > nzplen) {
nzplen = plen;
nzpos = ppos;
}
}
}
if(plen >= root->ac_maxdepth && (new->pattern[ppos] || new->pattern[ppos + 1]))
break;
}
if(!new->pattern[ppos] && !new->pattern[ppos + 1] && nzplen) {
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_alt(root->mempool, new);
mpool_free(root->mempool, new->pattern);
mpool_free(root->mempool, new);
return CL_EMALFDB;
}
new->prefix = new->pattern;
new->prefix_length = ppos;
new->pattern = &new->prefix[ppos];
new->length -= ppos;
for(i = 0; i < new->prefix_length; i++)
if((new->prefix[i] & CLI_MATCH_WILDCARD) == CLI_MATCH_ALTERNATIVE)
new->alt_pattern++;
}
if(new->length > root->maxpatlen)
root->maxpatlen = new->length;
new->virname = cli_mpool_virname(root->mempool, (char *) virname, options & CL_DB_OFFICIAL);
if(!new->virname) {
mpool_free(root->mempool, new->prefix ? new->prefix : new->pattern);
mpool_ac_free_alt(root->mempool, new);
mpool_free(root->mempool, new);
return CL_EMEM;
}
if(new->lsigid[0])
root->ac_lsigtable[new->lsigid[1]]->virname = new->virname;
ret = cli_caloff(offset, NULL, -1, 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_alt(root->mempool, new);
mpool_free(root->mempool, new->virname);
mpool_free(root->mempool, new);
return ret;
}
if((ret = cli_ac_addpatt(root, new))) {
mpool_free(root->mempool, new->prefix ? new->prefix : new->pattern);
mpool_free(root->mempool, new->virname);
mpool_ac_free_alt(root->mempool, new);
mpool_free(root->mempool, new);
return ret;
}
if(new->offdata[0] != CLI_OFF_ANY && new->offdata[0] != CLI_OFF_ABSOLUTE) {
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;
}