/*
* Copyright (C) 2002 - 2006 Tomasz Kojm <tkojm@clamav.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, 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 <string.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include "clamav.h"
#include "others.h"
#include "matcher-ac.h"
#include "matcher-bm.h"
#include "md5.h"
#include "filetypes.h"
#include "matcher.h"
#include "pe.h"
#include "elf.h"
#include "execs.h"
#include "special.h"
#define MD5_BLOCKSIZE 4096
static int targettab[CL_TARGET_TABLE_SIZE] = { 0, CL_TYPE_MSEXE, CL_TYPE_MSOLE2, CL_TYPE_HTML, CL_TYPE_MAIL, CL_TYPE_GRAPHICS, CL_TYPE_ELF };
extern short cli_debug_flag;
#ifdef HAVE_HWACCEL
#include <sn_sigscan/sn_sigscan.h>
#define HWBUFFSIZE 32768
#endif
int cli_scanbuff(const char *buffer, unsigned int length, const char **virname, const struct cl_engine *engine, unsigned short ftype)
{
int ret = CL_CLEAN, i, tid = 0, *partcnt;
unsigned long int *partoff;
struct cli_matcher *groot, *troot = NULL;
#ifdef HAVE_HWACCEL
void *streamhandle;
void *resulthandle;
uint32_t datamask[2] = { 0xffffffff, 0xffffffff };
int count, hret;
unsigned long long offset;
#endif
if(!engine) {
cli_errmsg("cli_scanbuff: engine == NULL\n");
return CL_ENULLARG;
}
#ifdef HAVE_HWACCEL
if(engine->hwaccel) {
/* TODO: Setup proper data bitmask (need specs) */
if((hret = sn_sigscan_createstream(engine->hwdb, datamask, 2, &streamhandle)) < 0) {
cli_errmsg("cli_scanbuff: can't create new hardware stream: %d\n", hret);
return CL_EHWIO;
}
if((hret = sn_sigscan_writestream(streamhandle, buffer, length)) < 0) {
cli_errmsg("cli_scanbuff: can't write %u bytes to hardware stream: %d\n", length, hret);
sn_sigscan_closestream(streamhandle, &resulthandle);
return CL_EHWIO;
}
if((hret = sn_sigscan_closestream(streamhandle, &resulthandle)) < 0) {
cli_errmsg("cli_scanbuff: can't close hardware stream: %d\n", hret);
return CL_EHWIO;
}
count = sn_sigscan_resultcount(resulthandle);
cli_dbgmsg("cli_scanbuff: number of results: %d\n", count);
if(count > 0) {
if((hret = sn_sigscan_resultget(resulthandle, 0, virname, &offset)) < 0) {
cli_errmsg("cli_scanbuff: can't get hardware match result: %d\n", hret);
sn_sigscan_resultfree(resulthandle);
return CL_EHWIO;
} else {
cli_dbgmsg("cli_scanbuff: hardware match %s at %u\n", *virname, offset);
ret = CL_VIRUS;
}
}
if((hret = sn_sigscan_resultfree(resulthandle)) < 0) {
cli_errmsg("cli_scanbuff: can't free results: %d\n", ret);
return CL_EHWIO;
}
return ret;
}
#endif /* HAVE_HWACCEL */
groot = engine->root[0]; /* generic signatures */
if(ftype) {
for(i = 0; i < CL_TARGET_TABLE_SIZE; i++) {
if(targettab[i] == ftype) {
tid = i;
break;
}
}
if(tid)
troot = engine->root[tid];
}
if(troot) {
if((partcnt = (int *) cli_calloc(troot->ac_partsigs + 1, sizeof(int))) == NULL) {
cli_dbgmsg("cli_scanbuff(): unable to cli_calloc(%d, %d)\n", troot->ac_partsigs + 1, sizeof(int));
return CL_EMEM;
}
if((partoff = (unsigned long int *) cli_calloc(troot->ac_partsigs + 1, sizeof(unsigned long int))) == NULL) {
cli_dbgmsg("cli_scanbuff(): unable to cli_calloc(%d, %d)\n", troot->ac_partsigs + 1, sizeof(unsigned long int));
free(partcnt);
return CL_EMEM;
}
if(troot->ac_only || (ret = cli_bm_scanbuff(buffer, length, virname, troot, 0, ftype, -1)) != CL_VIRUS)
ret = cli_ac_scanbuff(buffer, length, virname, troot, partcnt, 0, 0, partoff, ftype, -1, NULL);
free(partcnt);
free(partoff);
if(ret == CL_VIRUS)
return ret;
}
if((partcnt = (int *) cli_calloc(groot->ac_partsigs + 1, sizeof(int))) == NULL) {
cli_dbgmsg("cli_scanbuff(): unable to cli_calloc(%d, %d)\n", groot->ac_partsigs + 1, sizeof(int));
return CL_EMEM;
}
if((partoff = (unsigned long int *) cli_calloc(groot->ac_partsigs + 1, sizeof(unsigned long int))) == NULL) {
cli_dbgmsg("cli_scanbuff(): unable to cli_calloc(%d, %d)\n", groot->ac_partsigs + 1, sizeof(unsigned long int));
free(partcnt);
return CL_EMEM;
}
if(groot->ac_only || (ret = cli_bm_scanbuff(buffer, length, virname, groot, 0, ftype, -1)) != CL_VIRUS)
ret = cli_ac_scanbuff(buffer, length, virname, groot, partcnt, 0, 0, partoff, ftype, -1, NULL);
free(partcnt);
free(partoff);
return ret;
}
static struct cli_md5_node *cli_vermd5(const unsigned char *md5, const struct cl_engine *engine)
{
struct cli_md5_node *pt;
if(!(pt = engine->md5_hlist[md5[0] & 0xff]))
return NULL;
while(pt) {
if(!memcmp(pt->md5, md5, 16))
return pt;
pt = pt->next;
}
return NULL;
}
static long int cli_caloff(const char *offstr, int fd, unsigned short ftype)
{
struct cli_exe_info exeinfo;
int (*einfo)(int, struct cli_exe_info *) = NULL;
long int offset = -1;
int n;
if(ftype == CL_TYPE_MSEXE)
einfo = cli_peheader;
else if(ftype == CL_TYPE_ELF)
einfo = cli_elfheader;
if(isdigit(offstr[0])) {
return atoi(offstr);
} else if(einfo && (!strncmp(offstr, "EP+", 3) || !strncmp(offstr, "EP-", 3))) {
if((n = lseek(fd, 0, SEEK_CUR)) == -1) {
cli_dbgmsg("Invalid descriptor\n");
return -1;
}
lseek(fd, 0, SEEK_SET);
if(einfo(fd, &exeinfo)) {
lseek(fd, n, SEEK_SET);
return -1;
}
free(exeinfo.section);
lseek(fd, n, SEEK_SET);
if(offstr[2] == '+')
return exeinfo.ep + atoi(offstr + 3);
else
return exeinfo.ep - atoi(offstr + 3);
} else if(einfo && offstr[0] == 'S') {
if((n = lseek(fd, 0, SEEK_CUR)) == -1) {
cli_dbgmsg("Invalid descriptor\n");
return -1;
}
lseek(fd, 0, SEEK_SET);
if(einfo(fd, &exeinfo)) {
lseek(fd, n, SEEK_SET);
return -1;
}
lseek(fd, n, SEEK_SET);
if(!strncmp(offstr, "SL", 2)) {
if(sscanf(offstr, "SL+%ld", &offset) != 1) {
free(exeinfo.section);
return -1;
}
offset += exeinfo.section[exeinfo.nsections - 1].raw;
} else {
if(sscanf(offstr, "S%d+%ld", &n, &offset) != 2) {
free(exeinfo.section);
return -1;
}
if(n >= exeinfo.nsections) {
free(exeinfo.section);
return -1;
}
offset += exeinfo.section[n].raw;
}
free(exeinfo.section);
return offset;
} else if(!strncmp(offstr, "EOF-", 4)) {
struct stat sb;
if(fstat(fd, &sb) == -1)
return -1;
return sb.st_size - atoi(offstr + 4);
}
return -1;
}
int cli_checkfp(int fd, const struct cl_engine *engine)
{
struct cli_md5_node *md5_node;
unsigned char *digest;
if(engine->md5_hlist) {
if(!(digest = cli_md5digest(fd))) {
cli_errmsg("cli_checkfp(): Can't generate MD5 checksum\n");
return 0;
}
if((md5_node = cli_vermd5(digest, engine)) && md5_node->fp) {
struct stat sb;
if(fstat(fd, &sb))
return CL_EIO;
if((unsigned int) sb.st_size != md5_node->size) {
cli_warnmsg("Detected false positive MD5 match. Please report.\n");
} else {
cli_dbgmsg("Eliminated false positive match (fp sig: %s)\n", md5_node->virname);
free(digest);
return 1;
}
}
free(digest);
}
return 0;
}
int cli_validatesig(unsigned short target, unsigned short ftype, const char *offstr, unsigned long int fileoff, int desc, const char *virname)
{
if(offstr && desc != -1) {
long int off = cli_caloff(offstr, desc, ftype);
if(off == -1) {
cli_dbgmsg("Bad offset in signature (%s)\n", virname);
return 0;
}
if(fileoff != (unsigned long int) off) {
cli_dbgmsg("Virus offset: %d, expected: %d (%s)\n", fileoff, off, virname);
return 0;
}
}
return 1;
}
int cli_scandesc(int desc, cli_ctx *ctx, unsigned short otfrec, unsigned short ftype, struct cli_matched_type **ftoffset)
{
char *buffer, *buff, *endbl, *pt;
int ret = CL_CLEAN, *gpartcnt, *tpartcnt, type = CL_CLEAN, i, tid = 0, bytes;
unsigned int buffersize, length, maxpatlen, shift = 0;
unsigned long int *gpartoff, *tpartoff, offset = 0;
MD5_CTX md5ctx;
unsigned char digest[16];
struct cli_md5_node *md5_node;
struct cli_matcher *groot, *troot = NULL;
#ifdef HAVE_HWACCEL
void *streamhandle;
void *resulthandle;
unsigned long long hoffset;
uint32_t datamask[2] = { 0xffffffff, 0xffffffff };
int count, hret;
#endif
if(!ctx->engine) {
cli_errmsg("cli_scandesc: engine == NULL\n");
return CL_ENULLARG;
}
#ifdef HAVE_HWACCEL
if(ctx->engine->hwaccel) {
/* TODO: Setup proper data bitmask (need specs) */
if((hret = sn_sigscan_createstream(ctx->engine->hwdb, datamask, 2, &streamhandle)) < 0) {
cli_errmsg("cli_scandesc: can't create new hardware stream: %d\n", hret);
return CL_EHWIO;
}
if(!(buffer = (char *) cli_calloc(HWBUFFSIZE, sizeof(char)))) {
cli_dbgmsg("cli_scandesc: unable to cli_calloc(%u)\n", HWBUFFSIZE);
return CL_EMEM;
}
while((bytes = cli_readn(desc, buffer, HWBUFFSIZE)) > 0) {
if((hret = sn_sigscan_writestream(streamhandle, buffer, bytes)) < 0) {
cli_errmsg("cli_scandesc: can't write to hardware stream: %d\n", hret);
ret = CL_EHWIO;
break;
} else {
if(ctx->scanned)
*ctx->scanned += bytes / CL_COUNT_PRECISION;
}
}
free(buffer);
if((hret = sn_sigscan_closestream(streamhandle, &resulthandle)) < 0) {
cli_errmsg("cli_scandesc: can't close hardware stream: %d\n", hret);
return CL_EHWIO;
}
count = sn_sigscan_resultcount(resulthandle);
cli_dbgmsg("cli_scandesc: number of results: %d\n", count);
if(count > 0) {
if((hret = sn_sigscan_resultget(resulthandle, 0, ctx->virname, &hoffset)) < 0) {
cli_errmsg("cli_scandesc: can't get hardware match result: %d\n", hret);
sn_sigscan_resultfree(resulthandle);
return CL_EHWIO;
} else {
cli_dbgmsg("cli_scandesc: hardware match %s at %u\n", *ctx->virname, hoffset);
ret = CL_VIRUS;
}
}
if((hret = sn_sigscan_resultfree(resulthandle)) < 0) {
cli_errmsg("cli_scandesc: can't free results: %d\n", ret);
return CL_EHWIO;
}
return ret;
}
#endif /* HAVE_HWACCEL */
groot = ctx->engine->root[0]; /* generic signatures */
if(ftype) {
for(i = 0; i < CL_TARGET_TABLE_SIZE; i++) {
if(targettab[i] == ftype) {
tid = i;
break;
}
}
if(tid)
troot = ctx->engine->root[tid];
}
if(troot)
maxpatlen = MAX(troot->maxpatlen, groot->maxpatlen);
else
maxpatlen = groot->maxpatlen;
/* prepare the buffer */
buffersize = maxpatlen + SCANBUFF;
if(!(buffer = (char *) cli_calloc(buffersize, sizeof(char)))) {
cli_dbgmsg("cli_scandesc(): unable to cli_calloc(%d)\n", buffersize);
return CL_EMEM;
}
if((gpartcnt = (int *) cli_calloc(groot->ac_partsigs + 1, sizeof(int))) == NULL) {
cli_dbgmsg("cli_scandesc(): unable to cli_calloc(%d, %d)\n", groot->ac_partsigs + 1, sizeof(int));
free(buffer);
return CL_EMEM;
}
if((gpartoff = (unsigned long int *) cli_calloc(groot->ac_partsigs + 1, sizeof(unsigned long int))) == NULL) {
cli_dbgmsg("cli_scandesc(): unable to cli_calloc(%d, %d)\n", groot->ac_partsigs + 1, sizeof(unsigned long int));
free(buffer);
free(gpartcnt);
return CL_EMEM;
}
if(troot) {
if((tpartcnt = (int *) cli_calloc(troot->ac_partsigs + 1, sizeof(int))) == NULL) {
cli_dbgmsg("cli_scandesc(): unable to cli_calloc(%d, %d)\n", troot->ac_partsigs + 1, sizeof(int));
free(buffer);
free(gpartcnt);
free(gpartoff);
return CL_EMEM;
}
if((tpartoff = (unsigned long int *) cli_calloc(troot->ac_partsigs + 1, sizeof(unsigned long int))) == NULL) {
cli_dbgmsg("cli_scandesc(): unable to cli_calloc(%d, %d)\n", troot->ac_partsigs + 1, sizeof(unsigned long int));
free(buffer);
free(gpartcnt);
free(gpartoff);
free(tpartcnt);
return CL_EMEM;
}
}
if(ctx->engine->md5_hlist)
MD5_Init(&md5ctx);
buff = buffer;
buff += maxpatlen; /* pointer to read data block */
endbl = buff + SCANBUFF - maxpatlen; /* pointer to the last block
* length of maxpatlen
*/
pt = buff;
while((bytes = cli_readn(desc, buff + shift, SCANBUFF - shift)) > 0) {
if(ctx->scanned)
*ctx->scanned += bytes / CL_COUNT_PRECISION;
length = shift + bytes;
if(pt == buffer)
length += maxpatlen;
if(troot) {
if(troot->ac_only || (ret = cli_bm_scanbuff(pt, length, ctx->virname, troot, offset, ftype, desc)) != CL_VIRUS)
ret = cli_ac_scanbuff(pt, length, ctx->virname, troot, tpartcnt, otfrec, offset, tpartoff, ftype, desc, ftoffset);
if(ret == CL_VIRUS) {
free(buffer);
free(gpartcnt);
free(gpartoff);
free(tpartcnt);
free(tpartoff);
lseek(desc, 0, SEEK_SET);
if(cli_checkfp(desc, ctx->engine))
return CL_CLEAN;
else
return CL_VIRUS;
}
}
if(groot->ac_only || (ret = cli_bm_scanbuff(pt, length, ctx->virname, groot, offset, ftype, desc)) != CL_VIRUS)
ret = cli_ac_scanbuff(pt, length, ctx->virname, groot, gpartcnt, otfrec, offset, gpartoff, ftype, desc, ftoffset);
if(ret == CL_VIRUS) {
free(buffer);
free(gpartcnt);
free(gpartoff);
if(troot) {
free(tpartcnt);
free(tpartoff);
}
lseek(desc, 0, SEEK_SET);
if(cli_checkfp(desc, ctx->engine))
return CL_CLEAN;
else
return CL_VIRUS;
} else if(otfrec && ret >= CL_TYPENO) {
if(ret >= type)
type = ret;
}
if(ctx->engine->md5_hlist)
MD5_Update(&md5ctx, buff + shift, bytes);
if(bytes + shift == SCANBUFF) {
memmove(buffer, endbl, maxpatlen);
offset += SCANBUFF;
if(pt == buff) {
pt = buffer;
offset -= maxpatlen;
}
shift = 0;
} else {
shift += bytes;
}
}
free(buffer);
free(gpartcnt);
free(gpartoff);
if(troot) {
free(tpartcnt);
free(tpartoff);
}
if(ctx->engine->md5_hlist) {
MD5_Final(digest, &md5ctx);
if(cli_debug_flag) {
char md5str[33];
int i;
pt = md5str;
for(i = 0; i < 16; i++) {
sprintf(pt, "%02x", digest[i]);
pt += 2;
}
md5str[32] = 0;
}
if((md5_node = cli_vermd5(digest, ctx->engine)) && !md5_node->fp) {
struct stat sb;
if(fstat(desc, &sb))
return CL_EIO;
if((unsigned int) sb.st_size != md5_node->size) {
cli_warnmsg("Detected false positive MD5 match. Please report.\n");
} else {
if(ctx->virname)
*ctx->virname = md5_node->virname;
return CL_VIRUS;
}
}
}
return otfrec ? type : CL_CLEAN;
}