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

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/*
* Copyright (C) 2004 - 2006 Tomasz Kojm <tkojm@clamav.net>
*
* With additions from aCaB <acab@clamav.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License 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 <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/stat.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <time.h>
#include "cltypes.h"
#include "clamav.h"
#include "others.h"
#include "pe.h"
#include "petite.h"
#include "fsg.h"
#include "spin.h"
#include "upx.h"
#include "yc.h"
#include "wwunpack.h"
#include "suecrypt.h"
#include "scanners.h"
#include "rebuildpe.h"
#include "str.h"
#include "execs.h"
#ifndef O_BINARY
#define O_BINARY 0
#endif
#define IMAGE_DOS_SIGNATURE 0x5a4d /* MZ */
#define IMAGE_DOS_SIGNATURE_OLD 0x4d5a /* ZM */
#define IMAGE_NT_SIGNATURE 0x00004550
#define PE32_SIGNATURE 0x010b
#define PE32P_SIGNATURE 0x020b
#define UPX_NRV2B "\x11\xdb\x11\xc9\x01\xdb\x75\x07\x8b\x1e\x83\xee\xfc\x11\xdb\x11\xc9\x11\xc9\x75\x20\x41\x01\xdb"
#define UPX_NRV2D "\x83\xf0\xff\x74\x78\xd1\xf8\x89\xc5\xeb\x0b\x01\xdb\x75\x07\x8b\x1e\x83\xee\xfc\x11\xdb\x11\xc9"
#define UPX_NRV2E "\xeb\x52\x31\xc9\x83\xe8\x03\x72\x11\xc1\xe0\x08\x8a\x06\x46\x83\xf0\xff\x74\x75\xd1\xf8\x89\xc5"
#define EC32(x) le32_to_host(x) /* Convert little endian to host */
#define EC16(x) le16_to_host(x)
extern short cli_leavetemps_flag;
struct offset_list {
uint32_t offset;
struct offset_list *next;
};
static uint32_t cli_rawaddr(uint32_t rva, struct pe_image_section_hdr *shp, uint16_t nos, unsigned int *err)
{
int i, found = 0;
for(i = 0; i < nos; i++) {
if(EC32(shp[i].VirtualAddress) <= rva && EC32(shp[i].VirtualAddress) + EC32(shp[i].SizeOfRawData) > rva) {
found = 1;
break;
}
}
if(!found) {
*err = 1;
return 0;
}
*err = 0;
return rva - EC32(shp[i].VirtualAddress) + EC32(shp[i].PointerToRawData);
}
static void xckriz(char **opcode, int *len, int checksize, int reg) {
while(*len>6) {
if (**opcode>='\x48' && **opcode<='\x4f' && **opcode!='\x4c') {
if ((char)(**opcode-reg)=='\x48') break;
(*len)--;
(*opcode)++;
continue;
}
if (**opcode>='\xb8' && **opcode<='\xbf' && **opcode!='\xbc') {
if (checksize && cli_readint32(*opcode+1)==0x0fd2) break;
(*len)-=5;
(*opcode)+=5;
continue;
}
if (**opcode=='\x81') {
(*len)-=6;
(*opcode)+=6;
continue;
}
break;
}
}
/*
static int cli_ddump(int desc, int offset, int size, const char *file)
{
int pos, ndesc, bread, sum = 0;
char buff[FILEBUFF];
cli_dbgmsg("in ddump()\n");
if((pos = lseek(desc, 0, SEEK_CUR)) == -1) {
cli_dbgmsg("Invalid descriptor\n");
return -1;
}
if(lseek(desc, offset, SEEK_SET) == -1) {
cli_dbgmsg("lseek() failed\n");
lseek(desc, pos, SEEK_SET);
return -1;
}
if((ndesc = open(file, O_WRONLY|O_CREAT|O_TRUNC|O_BINARY, S_IRWXU)) < 0) {
cli_dbgmsg("Can't create file %s\n", file);
lseek(desc, pos, SEEK_SET);
return -1;
}
while((bread = cli_readn(desc, buff, FILEBUFF)) > 0) {
if(sum + bread >= size) {
if(write(ndesc, buff, size - sum) == -1) {
cli_dbgmsg("Can't write to file\n");
lseek(desc, pos, SEEK_SET);
close(ndesc);
unlink(file);
return -1;
}
break;
} else {
if(write(ndesc, buff, bread) == -1) {
cli_dbgmsg("Can't write to file\n");
lseek(desc, pos, SEEK_SET);
close(ndesc);
unlink(file);
return -1;
}
}
sum += bread;
}
close(ndesc);
lseek(desc, pos, SEEK_SET);
return 0;
}
*/
int cli_scanpe(int desc, cli_ctx *ctx)
{
uint16_t e_magic; /* DOS signature ("MZ") */
uint16_t nsections;
uint32_t e_lfanew; /* address of new exe header */
uint32_t ep; /* entry point (raw) */
uint8_t polipos = 0;
time_t timestamp;
struct pe_image_file_hdr file_hdr;
struct pe_image_optional_hdr32 optional_hdr32;
struct pe_image_optional_hdr64 optional_hdr64;
struct pe_image_section_hdr *section_hdr;
struct stat sb;
char sname[9], buff[4096], *tempfile;
unsigned char *ubuff;
ssize_t bytes;
unsigned int i, found, upx_success = 0, min = 0, max = 0, err, broken = 0;
unsigned int ssize = 0, dsize = 0, dll = 0, pe_plus = 0;
int (*upxfn)(char *, uint32_t, char *, uint32_t *, uint32_t, uint32_t, uint32_t) = NULL;
char *src = NULL, *dest = NULL;
int ndesc, ret = CL_CLEAN;
size_t fsize;
if(cli_readn(desc, &e_magic, sizeof(e_magic)) != sizeof(e_magic)) {
cli_dbgmsg("Can't read DOS signature\n");
return CL_CLEAN;
}
if(EC16(e_magic) != IMAGE_DOS_SIGNATURE && EC16(e_magic) != IMAGE_DOS_SIGNATURE_OLD) {
cli_dbgmsg("Invalid DOS signature\n");
return CL_CLEAN;
}
lseek(desc, 58, SEEK_CUR); /* skip to the end of the DOS header */
if(cli_readn(desc, &e_lfanew, sizeof(e_lfanew)) != sizeof(e_lfanew)) {
cli_dbgmsg("Can't read new header address\n");
/* truncated header? */
if(DETECT_BROKEN) {
if(ctx->virname)
*ctx->virname = "Broken.Executable";
return CL_VIRUS;
}
return CL_CLEAN;
}
e_lfanew = EC32(e_lfanew);
cli_dbgmsg("e_lfanew == %d\n", e_lfanew);
if(!e_lfanew) {
cli_dbgmsg("Not a PE file\n");
return CL_CLEAN;
}
if(lseek(desc, e_lfanew, SEEK_SET) < 0) {
/* probably not a PE file */
cli_dbgmsg("Can't lseek to e_lfanew\n");
return CL_CLEAN;
}
if(cli_readn(desc, &file_hdr, sizeof(struct pe_image_file_hdr)) != sizeof(struct pe_image_file_hdr)) {
/* bad information in e_lfanew - probably not a PE file */
cli_dbgmsg("Can't read file header\n");
return CL_CLEAN;
}
if(EC32(file_hdr.Magic) != IMAGE_NT_SIGNATURE) {
cli_dbgmsg("Invalid PE signature (probably NE file)\n");
return CL_CLEAN;
}
if(EC16(file_hdr.Characteristics) & 0x2000) {
cli_dbgmsg("File type: DLL\n");
dll = 1;
} else if(EC16(file_hdr.Characteristics) & 0x01) {
cli_dbgmsg("File type: Executable\n");
}
switch(EC16(file_hdr.Machine)) {
case 0x0:
cli_dbgmsg("Machine type: Unknown\n");
case 0x14c:
cli_dbgmsg("Machine type: 80386\n");
break;
case 0x14d:
cli_dbgmsg("Machine type: 80486\n");
break;
case 0x14e:
cli_dbgmsg("Machine type: 80586\n");
break;
case 0x160:
cli_dbgmsg("Machine type: R30000 (big-endian)\n");
break;
case 0x162:
cli_dbgmsg("Machine type: R3000\n");
break;
case 0x166:
cli_dbgmsg("Machine type: R4000\n");
break;
case 0x168:
cli_dbgmsg("Machine type: R10000\n");
break;
case 0x184:
cli_dbgmsg("Machine type: DEC Alpha AXP\n");
break;
case 0x284:
cli_dbgmsg("Machine type: DEC Alpha AXP 64bit\n");
break;
case 0x1f0:
cli_dbgmsg("Machine type: PowerPC\n");
break;
case 0x200:
cli_dbgmsg("Machine type: IA64\n");
break;
case 0x268:
cli_dbgmsg("Machine type: M68k\n");
break;
case 0x266:
cli_dbgmsg("Machine type: MIPS16\n");
break;
case 0x366:
cli_dbgmsg("Machine type: MIPS+FPU\n");
break;
case 0x466:
cli_dbgmsg("Machine type: MIPS16+FPU\n");
break;
case 0x1a2:
cli_dbgmsg("Machine type: Hitachi SH3\n");
break;
case 0x1a3:
cli_dbgmsg("Machine type: Hitachi SH3-DSP\n");
break;
case 0x1a4:
cli_dbgmsg("Machine type: Hitachi SH3-E\n");
break;
case 0x1a6:
cli_dbgmsg("Machine type: Hitachi SH4\n");
break;
case 0x1a8:
cli_dbgmsg("Machine type: Hitachi SH5\n");
break;
case 0x1c0:
cli_dbgmsg("Machine type: ARM\n");
break;
case 0x1c2:
cli_dbgmsg("Machine type: THUMB\n");
break;
case 0x1d3:
cli_dbgmsg("Machine type: AM33\n");
break;
case 0x520:
cli_dbgmsg("Machine type: Infineon TriCore\n");
break;
case 0xcef:
cli_dbgmsg("Machine type: CEF\n");
break;
case 0xebc:
cli_dbgmsg("Machine type: EFI Byte Code\n");
break;
case 0x9041:
cli_dbgmsg("Machine type: M32R\n");
break;
case 0xc0ee:
cli_dbgmsg("Machine type: CEE\n");
break;
case 0x8664:
cli_dbgmsg("Machine type: AMD64\n");
break;
default:
cli_warnmsg("Unknown machine type in PE header (0x%x)\n", EC16(file_hdr.Machine));
}
nsections = EC16(file_hdr.NumberOfSections);
if(nsections < 1 || nsections > 99) {
if(DETECT_BROKEN) {
if(ctx->virname)
*ctx->virname = "Broken.Executable";
return CL_VIRUS;
}
if(nsections)
cli_warnmsg("PE file contains %d sections\n", nsections);
else
cli_warnmsg("PE file contains no sections\n");
return CL_CLEAN;
}
cli_dbgmsg("NumberOfSections: %d\n", nsections);
timestamp = (time_t) EC32(file_hdr.TimeDateStamp);
cli_dbgmsg("TimeDateStamp: %s", ctime(&timestamp));
cli_dbgmsg("SizeOfOptionalHeader: %d\n", EC16(file_hdr.SizeOfOptionalHeader));
if(EC16(file_hdr.SizeOfOptionalHeader) != sizeof(struct pe_image_optional_hdr32)) {
if(EC16(file_hdr.SizeOfOptionalHeader) == sizeof(struct pe_image_optional_hdr64)) {
pe_plus = 1;
} else {
cli_dbgmsg("Incorrect value of SizeOfOptionalHeader\n");
if(DETECT_BROKEN) {
if(ctx->virname)
*ctx->virname = "Broken.Executable";
return CL_VIRUS;
}
return CL_CLEAN;
}
}
if(!pe_plus) { /* PE */
if(cli_readn(desc, &optional_hdr32, sizeof(struct pe_image_optional_hdr32)) != sizeof(struct pe_image_optional_hdr32)) {
cli_dbgmsg("Can't read optional file header\n");
if(DETECT_BROKEN) {
if(ctx->virname)
*ctx->virname = "Broken.Executable";
return CL_VIRUS;
}
return CL_CLEAN;
}
if(EC16(optional_hdr32.Magic) != PE32_SIGNATURE) {
cli_warnmsg("Incorrect magic number in optional header\n");
if(DETECT_BROKEN) {
if(ctx->virname)
*ctx->virname = "Broken.Executable";
return CL_VIRUS;
}
}
cli_dbgmsg("File format: PE\n");
cli_dbgmsg("MajorLinkerVersion: %d\n", optional_hdr32.MajorLinkerVersion);
cli_dbgmsg("MinorLinkerVersion: %d\n", optional_hdr32.MinorLinkerVersion);
cli_dbgmsg("SizeOfCode: %d\n", EC32(optional_hdr32.SizeOfCode));
cli_dbgmsg("SizeOfInitializedData: %d\n", EC32(optional_hdr32.SizeOfInitializedData));
cli_dbgmsg("SizeOfUninitializedData: %d\n", EC32(optional_hdr32.SizeOfUninitializedData));
cli_dbgmsg("AddressOfEntryPoint: 0x%x\n", EC32(optional_hdr32.AddressOfEntryPoint));
cli_dbgmsg("BaseOfCode: 0x%x\n", EC32(optional_hdr32.BaseOfCode));
cli_dbgmsg("SectionAlignment: %d\n", EC32(optional_hdr32.SectionAlignment));
cli_dbgmsg("FileAlignment: %d\n", EC32(optional_hdr32.FileAlignment));
cli_dbgmsg("MajorSubsystemVersion: %d\n", EC16(optional_hdr32.MajorSubsystemVersion));
cli_dbgmsg("MinorSubsystemVersion: %d\n", EC16(optional_hdr32.MinorSubsystemVersion));
cli_dbgmsg("SizeOfImage: %d\n", EC32(optional_hdr32.SizeOfImage));
cli_dbgmsg("SizeOfHeaders: %d\n", EC32(optional_hdr32.SizeOfHeaders));
cli_dbgmsg("NumberOfRvaAndSizes: %d\n", EC32(optional_hdr32.NumberOfRvaAndSizes));
} else { /* PE+ */
if(cli_readn(desc, &optional_hdr64, sizeof(struct pe_image_optional_hdr64)) != sizeof(struct pe_image_optional_hdr64)) {
cli_dbgmsg("Can't optional file header\n");
if(DETECT_BROKEN) {
if(ctx->virname)
*ctx->virname = "Broken.Executable";
return CL_VIRUS;
}
return CL_CLEAN;
}
if(EC16(optional_hdr64.Magic) != PE32P_SIGNATURE) {
cli_warnmsg("Incorrect magic number in optional header\n");
if(DETECT_BROKEN) {
if(ctx->virname)
*ctx->virname = "Broken.Executable";
return CL_VIRUS;
}
}
cli_dbgmsg("File format: PE32+\n");
cli_dbgmsg("MajorLinkerVersion: %d\n", optional_hdr64.MajorLinkerVersion);
cli_dbgmsg("MinorLinkerVersion: %d\n", optional_hdr64.MinorLinkerVersion);
cli_dbgmsg("SizeOfCode: %d\n", EC32(optional_hdr64.SizeOfCode));
cli_dbgmsg("SizeOfInitializedData: %d\n", EC32(optional_hdr64.SizeOfInitializedData));
cli_dbgmsg("SizeOfUninitializedData: %d\n", EC32(optional_hdr64.SizeOfUninitializedData));
cli_dbgmsg("AddressOfEntryPoint: 0x%x\n", EC32(optional_hdr64.AddressOfEntryPoint));
cli_dbgmsg("BaseOfCode: 0x%x\n", EC32(optional_hdr64.BaseOfCode));
cli_dbgmsg("SectionAlignment: %d\n", EC32(optional_hdr64.SectionAlignment));
cli_dbgmsg("FileAlignment: %d\n", EC32(optional_hdr64.FileAlignment));
cli_dbgmsg("MajorSubsystemVersion: %d\n", EC16(optional_hdr64.MajorSubsystemVersion));
cli_dbgmsg("MinorSubsystemVersion: %d\n", EC16(optional_hdr64.MinorSubsystemVersion));
cli_dbgmsg("SizeOfImage: %d\n", EC32(optional_hdr64.SizeOfImage));
cli_dbgmsg("SizeOfHeaders: %d\n", EC32(optional_hdr64.SizeOfHeaders));
cli_dbgmsg("NumberOfRvaAndSizes: %d\n", EC32(optional_hdr64.NumberOfRvaAndSizes));
}
switch(pe_plus ? EC16(optional_hdr64.Subsystem) : EC16(optional_hdr32.Subsystem)) {
case 0:
cli_dbgmsg("Subsystem: Unknown\n");
break;
case 1:
cli_dbgmsg("Subsystem: Native (a driver ?)\n");
break;
case 2:
cli_dbgmsg("Subsystem: Win32 GUI\n");
break;
case 3:
cli_dbgmsg("Subsystem: Win32 console\n");
break;
case 5:
cli_dbgmsg("Subsystem: OS/2 console\n");
break;
case 7:
cli_dbgmsg("Subsystem: POSIX console\n");
break;
case 8:
cli_dbgmsg("Subsystem: Native Win9x driver\n");
break;
case 9:
cli_dbgmsg("Subsystem: WinCE GUI\n");
break;
case 10:
cli_dbgmsg("Subsystem: EFI application\n");
break;
case 11:
cli_dbgmsg("Subsystem: EFI driver\n");
break;
case 12:
cli_dbgmsg("Subsystem: EFI runtime driver\n");
break;
default:
cli_warnmsg("Unknown subsystem in PE header (0x%x)\n", pe_plus ? EC16(optional_hdr64.Subsystem) : EC16(optional_hdr32.Subsystem));
}
cli_dbgmsg("------------------------------------\n");
if(fstat(desc, &sb) == -1) {
cli_dbgmsg("fstat failed\n");
return CL_EIO;
}
fsize = sb.st_size;
section_hdr = (struct pe_image_section_hdr *) cli_calloc(nsections, sizeof(struct pe_image_section_hdr));
if(!section_hdr) {
cli_dbgmsg("Can't allocate memory for section headers\n");
return CL_EMEM;
}
for(i = 0; i < nsections; i++) {
if(cli_readn(desc, &section_hdr[i], sizeof(struct pe_image_section_hdr)) != sizeof(struct pe_image_section_hdr)) {
cli_dbgmsg("Can't read section header\n");
cli_dbgmsg("Possibly broken PE file\n");
free(section_hdr);
if(DETECT_BROKEN) {
if(ctx->virname)
*ctx->virname = "Broken.Executable";
return CL_VIRUS;
}
return CL_CLEAN;
}
strncpy(sname, (char *) section_hdr[i].Name, 8);
sname[8] = 0;
cli_dbgmsg("Section %d\n", i);
cli_dbgmsg("Section name: %s\n", sname);
cli_dbgmsg("VirtualSize: %d\n", EC32(section_hdr[i].VirtualSize));
cli_dbgmsg("VirtualAddress: 0x%x\n", EC32(section_hdr[i].VirtualAddress));
cli_dbgmsg("SizeOfRawData: %d\n", EC32(section_hdr[i].SizeOfRawData));
cli_dbgmsg("PointerToRawData: 0x%x (%d)\n", EC32(section_hdr[i].PointerToRawData), EC32(section_hdr[i].PointerToRawData));
if(EC32(section_hdr[i].Characteristics) & 0x20) {
cli_dbgmsg("Section contains executable code\n");
if(EC32(section_hdr[i].VirtualSize) < EC32(section_hdr[i].SizeOfRawData)) {
cli_dbgmsg("Section contains free space\n");
/*
cli_dbgmsg("Dumping %d bytes\n", section_hdr.SizeOfRawData - section_hdr.VirtualSize);
ddump(desc, section_hdr.PointerToRawData + section_hdr.VirtualSize, section_hdr.SizeOfRawData - section_hdr.VirtualSize, cli_gentemp(NULL));
*/
}
}
if(EC32(section_hdr[i].Characteristics) & 0x20000000)
cli_dbgmsg("Section's memory is executable\n");
if(EC32(section_hdr[i].Characteristics) & 0x80000000)
cli_dbgmsg("Section's memory is writeable\n");
cli_dbgmsg("------------------------------------\n");
if(!CLI_ISCONTAINED2(0, (uint32_t) fsize, EC32(section_hdr[i].PointerToRawData), EC32(section_hdr[i].SizeOfRawData)) || EC32(section_hdr[i].PointerToRawData) > fsize) {
cli_dbgmsg("Possibly broken PE file - Section %d out of file (Offset@ %d, Rsize %d, Total filesize %d)\n", i, EC32(section_hdr[i].PointerToRawData), EC32(section_hdr[i].SizeOfRawData), fsize);
if(DETECT_BROKEN) {
if(ctx->virname)
*ctx->virname = "Broken.Executable";
free(section_hdr);
return CL_VIRUS;
}
broken = 1;
}
if(!i) {
min = EC32(section_hdr[i].VirtualAddress);
max = EC32(section_hdr[i].VirtualAddress) + EC32(section_hdr[i].SizeOfRawData);
} else {
if(EC32(section_hdr[i].VirtualAddress) < min)
min = EC32(section_hdr[i].VirtualAddress);
if(EC32(section_hdr[i].VirtualAddress) + EC32(section_hdr[i].SizeOfRawData) > max)
max = EC32(section_hdr[i].VirtualAddress) + EC32(section_hdr[i].SizeOfRawData);
}
if(SCAN_ALGO && !strlen(sname)) {
if(EC32(section_hdr[i].VirtualSize) > 40000 && EC32(section_hdr[i].VirtualSize) < 70000) {
if(EC32(section_hdr[i].Characteristics) == 0xe0000060) {
polipos = i;
}
}
}
}
if(pe_plus)
ep = EC32(optional_hdr64.AddressOfEntryPoint);
else
ep = EC32(optional_hdr32.AddressOfEntryPoint);
if(ep >= min && !(ep = cli_rawaddr(ep, section_hdr, nsections, &err)) && err) {
cli_dbgmsg("Possibly broken PE file\n");
free(section_hdr);
if(DETECT_BROKEN) {
if(ctx->virname)
*ctx->virname = "Broken.Executable";
return CL_VIRUS;
}
return CL_CLEAN;
}
cli_dbgmsg("EntryPoint offset: 0x%x (%d)\n", ep, ep);
/* Attempt to detect some popular polymorphic viruses */
/* W32.Parite.B */
if(SCAN_ALGO && !dll && ep == EC32(section_hdr[nsections - 1].PointerToRawData)) {
lseek(desc, ep, SEEK_SET);
if(cli_readn(desc, buff, 4096) == 4096) {
const char *pt = cli_memstr(buff, 4040, "\x47\x65\x74\x50\x72\x6f\x63\x41\x64\x64\x72\x65\x73\x73\x00", 15);
if(pt) {
uint32_t dw1, dw2;
pt += 15;
if(((dw1 = cli_readint32(pt)) ^ (dw2 = cli_readint32(pt + 4))) == 0x505a4f && ((dw1 = cli_readint32(pt + 8)) ^ (dw2 = cli_readint32(pt + 12))) == 0xffffb && ((dw1 = cli_readint32(pt + 16)) ^ (dw2 = cli_readint32(pt + 20))) == 0xb8) {
*ctx->virname = "W32.Parite.B";
free(section_hdr);
return CL_VIRUS;
}
}
}
}
/* Kriz */
if(SCAN_ALGO && CLI_ISCONTAINED(EC32(section_hdr[nsections - 1].PointerToRawData), EC32(section_hdr[nsections - 1].SizeOfRawData), ep, 0x0fd2)) {
cli_dbgmsg("in kriz\n");
lseek(desc, ep, SEEK_SET);
if(cli_readn(desc, buff, 200) == 200) {
while (1) {
char *krizpos=buff+3;
char *krizmov, *krizxor;
int krizleft = 200-3;
int krizrega,krizregb;
if (buff[1]!='\x9c' || buff[2]!='\x60') break; /* EP+1 */
xckriz(&krizpos, &krizleft, 0, 8);
if (krizleft < 6 || *krizpos!='\xe8' || krizpos[2] || krizpos[3] || krizpos[4]) break; /* call DELTA */
krizleft-=5+(unsigned char)krizpos[1];
if (krizleft < 2) break;
krizpos+=5+(unsigned char)krizpos[1];
if (*krizpos<'\x58' || *krizpos>'\x5f' || *krizpos=='\x5c') break; /* pop DELTA */
krizrega=*krizpos-'\x58';
cli_dbgmsg("kriz: pop delta using %d\n", krizrega);
krizpos+=1;
krizleft-=1;
xckriz(&krizpos, &krizleft, 1, 8);
if (krizleft <6 || *krizpos<'\xb8' || *krizpos>'\xbf' || *krizpos=='\xbc' || cli_readint32(krizpos+1)!=0x0fd2) break;
krizregb=*krizpos-'\xb8';
if (krizrega==krizregb) break;
cli_dbgmsg("kriz: using %d for size\n", krizregb);
krizpos+=5;
krizleft-=5;
krizmov = krizpos;
xckriz(&krizpos, &krizleft, 0, 8);
krizxor=krizpos;
if (krizleft && *krizpos=='\x3e') {
/* strip ds: */
krizpos++;
krizleft--;
}
if (krizleft<8 || *krizpos!='\x80' || (char)(krizpos[1]-krizrega)!='\xb0') {
cli_dbgmsg("kriz: bogus opcode or register\n");
break;
}
krizpos+=7;
krizleft-=7;
xckriz(&krizpos, &krizleft, 0, krizrega);
if (! krizleft || (char)(*krizpos-krizrega)!='\x48') break; /* dec delta */
krizpos++;
krizleft--;
cli_dbgmsg("kriz: dec delta found\n");
xckriz(&krizpos, &krizleft, 0, krizregb);
if (krizleft <4 || (char)(*krizpos-krizregb)!='\x48' || krizpos[1]!='\x75') break; /* dec size + jne loop */
if (krizpos+3+(int)krizpos[2]<krizmov || krizpos+3+(int)krizpos[2]>krizxor) {
cli_dbgmsg("kriz: jmp back out of range (%d>%d>%d)\n", krizmov-(krizpos+3), (int)krizpos[2], krizxor-(krizpos+3));
break;
}
*ctx->virname = "Win32.Kriz";
free(section_hdr);
return CL_VIRUS;
}
}
}
/* W32.Magistr.A/B */
if(SCAN_ALGO && !dll && (EC32(section_hdr[nsections - 1].Characteristics) & 0x80000000)) {
uint32_t rsize, vsize;
rsize = EC32(section_hdr[nsections - 1].SizeOfRawData);
vsize = EC32(section_hdr[nsections - 1].VirtualSize);
if(rsize >= 0x612c && vsize >= 0x612c && ((vsize & 0xff) == 0xec)) {
int bw = rsize < 0x7000 ? rsize : 0x7000;
lseek(desc, EC32(section_hdr[nsections - 1].PointerToRawData) + rsize - bw, SEEK_SET);
if(cli_readn(desc, buff, 4096) == 4096) {
if(cli_memstr(buff, 4091, "\xe8\x2c\x61\x00\x00", 5)) {
*ctx->virname = "W32.Magistr.A";
free(section_hdr);
return CL_VIRUS;
}
}
} else if(rsize >= 0x7000 && vsize >= 0x7000 && ((vsize & 0xff) == 0xed)) {
int bw = rsize < 0x8000 ? rsize : 0x8000;
lseek(desc, EC32(section_hdr[nsections - 1].PointerToRawData) + rsize - bw, SEEK_SET);
if(cli_readn(desc, buff, 4096) == 4096) {
if(cli_memstr(buff, 4091, "\xe8\x04\x72\x00\x00", 5)) {
*ctx->virname = "W32.Magistr.B";
free(section_hdr);
return CL_VIRUS;
}
}
}
}
/* W32.Polipos.A */
if(polipos && !dll && !pe_plus && nsections > 2 && nsections < 13 && e_lfanew <= 0x800 && (EC16(optional_hdr32.Subsystem) == 2 || EC16(optional_hdr32.Subsystem) == 3) && EC16(file_hdr.Machine) == 0x14c && optional_hdr32.SizeOfStackReserve >= 0x80000) {
uint32_t remaining = EC32(section_hdr[0].SizeOfRawData);
uint32_t chunk = sizeof(buff);
uint32_t val, shift, raddr, total = 0;
const char *jpt;
struct offset_list *offlist = NULL, *offnode;
cli_dbgmsg("Detected W32.Polipos.A characteristics\n");
if(remaining < chunk)
chunk = remaining;
lseek(desc, EC32(section_hdr[0].PointerToRawData), SEEK_SET);
while((bytes = cli_readn(desc, buff, chunk)) > 0) {
shift = 0;
while(bytes - 5 > shift) {
jpt = buff + shift;
if(*jpt!='\xe9' && *jpt!='\xe8') {
shift++;
continue;
}
val = cli_readint32(jpt + 1);
val += 5 + EC32(section_hdr[0].VirtualAddress) + total + shift;
raddr = cli_rawaddr(val, section_hdr, nsections, &err);
if(!err && (raddr >= EC32(section_hdr[polipos].PointerToRawData) && raddr < EC32(section_hdr[polipos].PointerToRawData) + EC32(section_hdr[polipos].SizeOfRawData)) && (!offlist || (raddr != offlist->offset))) {
offnode = (struct offset_list *) cli_malloc(sizeof(struct offset_list));
if(!offnode) {
free(section_hdr);
while(offlist) {
offnode = offlist;
offlist = offlist->next;
free(offnode);
}
return CL_EMEM;
}
offnode->offset = raddr;
offnode->next = offlist;
offlist = offnode;
}
shift++;
}
if(remaining < chunk) {
chunk = remaining;
} else {
remaining -= bytes;
if(remaining < chunk) {
chunk = remaining;
}
}
if(!remaining)
break;
total += bytes;
}
offnode = offlist;
while(offnode) {
cli_dbgmsg("Polipos: Checking offset 0x%x (%u)", offnode->offset, offnode->offset);
lseek(desc, offnode->offset, SEEK_SET);
if(cli_readn(desc, buff, 9) == 9) {
ubuff = (unsigned char *) buff;
if(ubuff[0] == 0x55 && ubuff[1] == 0x8b && ubuff[2] == 0xec &&
((ubuff[3] == 0x83 && ubuff[4] == 0xec && ubuff[6] == 0x60) || ubuff[3] == 0x60 ||
(ubuff[3] == 0x81 && ubuff[4] == 0xec && ubuff[7] == 0x00 && ubuff[8] == 0x00))) {
ret = CL_VIRUS;
*ctx->virname = "W32.Polipos.A";
break;
}
}
offnode = offnode->next;
}
while(offlist) {
offnode = offlist;
offlist = offlist->next;
free(offnode);
}
if(ret == CL_VIRUS) {
free(section_hdr);
return CL_VIRUS;
}
}
if(broken) {
free(section_hdr);
return CL_CLEAN;
}
if(pe_plus) { /* Do not continue for PE32+ files */
free(section_hdr);
return CL_CLEAN;
}
#ifdef CONFIG_EXPERIMENTAL
/* SUE */
if(nsections > 2 && EC32(optional_hdr32.AddressOfEntryPoint) == EC32(section_hdr[nsections - 1].VirtualAddress) && EC32(section_hdr[nsections - 1].SizeOfRawData) > 0x350 && EC32(section_hdr[nsections - 1].SizeOfRawData) < 0x292+0x350+1000) {
char *sue=buff+0x74;
uint32_t key;
if(lseek(desc, ep-4, SEEK_SET) == -1) {
cli_dbgmsg("SUE: lseek() failed - EP out of file\n");
free(section_hdr);
return CL_EIO;
}
if((unsigned int) cli_readn(desc, buff, EC32(section_hdr[nsections - 1].SizeOfRawData)+4) == EC32(section_hdr[nsections - 1].SizeOfRawData)+4) {
found=0;
while(CLI_ISCONTAINED(buff+4, EC32(section_hdr[nsections - 1].SizeOfRawData), sue, 4*3)) {
if((cli_readint32(sue)^cli_readint32(sue+4))==0x5c41090e && (cli_readint32(sue)^cli_readint32(sue+8))==0x021e0145) {
found=1;
key=(cli_readint32(sue)^0x6e72656b);
break;
}
sue++;
}
cli_dbgmsg("SUE: key(%x) found @%x\n", key, sue-buff);
if (found && CLI_ISCONTAINED(buff, EC32(section_hdr[nsections - 1].SizeOfRawData), sue-0x74, 0xbe) &&
(sue=sudecrypt(desc, fsize, section_hdr, nsections-1, sue, key, cli_readint32(buff), e_lfanew))) {
if(!(tempfile = cli_gentemp(NULL))) {
free(sue);
free(section_hdr);
return CL_EMEM;
}
if((ndesc = open(tempfile, O_RDWR|O_CREAT|O_TRUNC|O_BINARY, S_IRWXU)) < 0) {
cli_dbgmsg("sue: Can't create file %s\n", tempfile);
free(tempfile);
free(sue);
free(section_hdr);
return CL_EIO;
}
if((unsigned int) write(ndesc, sue, ep) != ep) {
cli_dbgmsg("sue: Can't write %d bytes\n", ep);
close(ndesc);
free(tempfile);
free(sue);
free(section_hdr);
return CL_EIO;
}
free(sue);
if (cli_leavetemps_flag)
cli_dbgmsg("SUE: Decrypted executable saved in %s\n", tempfile);
else
cli_dbgmsg("SUE: Executable decrypted\n");
fsync(ndesc);
lseek(ndesc, 0, SEEK_SET);
if(cli_magic_scandesc(ndesc, ctx) == CL_VIRUS) {
free(section_hdr);
close(ndesc);
if(!cli_leavetemps_flag)
unlink(tempfile);
free(tempfile);
return CL_VIRUS;
}
close(ndesc);
if(!cli_leavetemps_flag)
unlink(tempfile);
free(tempfile);
}
}
}
#endif
/* UPX & FSG support */
/* try to find the first section with physical size == 0 */
found = 0;
for(i = 0; i < (unsigned int) nsections - 1; i++) {
if(!section_hdr[i].SizeOfRawData && section_hdr[i].VirtualSize && section_hdr[i + 1].SizeOfRawData && section_hdr[i + 1].VirtualSize) {
found = 1;
cli_dbgmsg("UPX/FSG: empty section found - assuming compression\n");
break;
}
}
if(found) {
/* Check EP for UPX vs. FSG */
if(lseek(desc, ep, SEEK_SET) == -1) {
cli_dbgmsg("UPX/FSG: lseek() failed\n");
free(section_hdr);
return CL_EIO;
}
if(cli_readn(desc, buff, 168) != 168) {
cli_dbgmsg("UPX/FSG: Can't read 168 bytes at 0x%x (%d)\n", ep, ep);
cli_dbgmsg("UPX/FSG: Broken or not UPX/FSG compressed file\n");
free(section_hdr);
return CL_CLEAN;
}
if(buff[0] == '\x87' && buff[1] == '\x25') {
/* FSG v2.0 support - thanks to aCaB ! */
ssize = EC32(section_hdr[i + 1].SizeOfRawData);
dsize = EC32(section_hdr[i].VirtualSize);
while(found) {
uint32_t newesi, newedi, newebx, newedx;
if(ctx->limits && ctx->limits->maxfilesize && (ssize > ctx->limits->maxfilesize || dsize > ctx->limits->maxfilesize)) {
cli_dbgmsg("FSG: Sizes exceeded (ssize: %u, dsize: %u, max: %lu)\n", ssize, dsize , ctx->limits->maxfilesize);
free(section_hdr);
if(BLOCKMAX) {
*ctx->virname = "PE.FSG.ExceededFileSize";
return CL_VIRUS;
} else {
return CL_CLEAN;
}
}
if(ssize <= 0x19 || dsize <= ssize) {
cli_dbgmsg("FSG: Size mismatch (ssize: %d, dsize: %d)\n", ssize, dsize);
free(section_hdr);
return CL_CLEAN;
}
if((newedx = cli_readint32(buff + 2) - EC32(optional_hdr32.ImageBase)) < EC32(section_hdr[i + 1].VirtualAddress) || newedx >= EC32(section_hdr[i + 1].VirtualAddress) + EC32(section_hdr[i + 1].SizeOfRawData) - 4) {
cli_dbgmsg("FSG: xchg out of bounds (%x), giving up\n", newedx);
break;
}
if((src = (char *) cli_malloc(ssize)) == NULL) {
free(section_hdr);
return CL_EMEM;
}
lseek(desc, EC32(section_hdr[i + 1].PointerToRawData), SEEK_SET);
if((unsigned int) cli_readn(desc, src, ssize) != ssize) {
cli_dbgmsg("Can't read raw data of section %d\n", i);
free(section_hdr);
free(src);
return CL_EIO;
}
if(newedx < EC32(section_hdr[i + 1].VirtualAddress) || ((dest = src + newedx - EC32(section_hdr[i + 1].VirtualAddress)) < src && dest >= src + EC32(section_hdr[i + 1].VirtualAddress) + EC32(section_hdr[i + 1].SizeOfRawData) - 4)) {
cli_dbgmsg("FSG: New ESP out of bounds\n");
free(src);
break;
}
if((newedx = cli_readint32(dest) - EC32(optional_hdr32.ImageBase)) <= EC32(section_hdr[i + 1].VirtualAddress) || newedx >= EC32(section_hdr[i + 1].VirtualAddress) + EC32(section_hdr[i + 1].SizeOfRawData) - 4) {
cli_dbgmsg("FSG: New ESP (%x) is wrong\n", newedx);
free(src);
break;
}
if((dest = src + newedx - EC32(section_hdr[i + 1].VirtualAddress)) < src || dest >= src + EC32(section_hdr[i + 1].VirtualAddress) + EC32(section_hdr[i + 1].SizeOfRawData) - 32) {
cli_dbgmsg("FSG: New stack out of bounds\n");
free(src);
break;
}
newedi = cli_readint32(dest) - EC32(optional_hdr32.ImageBase);
newesi = cli_readint32(dest + 4) - EC32(optional_hdr32.ImageBase);
newebx = cli_readint32(dest + 16) - EC32(optional_hdr32.ImageBase);
newedx = cli_readint32(dest + 20);
if(newedi != EC32(section_hdr[i].VirtualAddress)) {
cli_dbgmsg("FSG: Bad destination buffer (edi is %x should be %x)\n", newedi, EC32(section_hdr[i].VirtualAddress));
free(src);
break;
}
if(newesi < EC32(section_hdr[i + 1].VirtualAddress) || newesi >= EC32(section_hdr[i + 1].VirtualAddress) + EC32(section_hdr[i + 1].SizeOfRawData)) {
cli_dbgmsg("FSG: Source buffer out of section bounds\n");
free(src);
break;
}
if(newebx < EC32(section_hdr[i + 1].VirtualAddress) || newebx >= EC32(section_hdr[i + 1].VirtualAddress) + EC32(section_hdr[i + 1].SizeOfRawData) - 16) {
cli_dbgmsg("FSG: Array of functions out of bounds\n");
free(src);
break;
}
newedx=cli_readint32(newebx + 12 - EC32(section_hdr[i + 1].VirtualAddress) + src) - EC32(optional_hdr32.ImageBase);
cli_dbgmsg("FSG: found old EP @%x\n",newedx);
if((dest = (char *) cli_calloc(dsize, sizeof(char))) == NULL) {
free(section_hdr);
free(src);
return CL_EMEM;
}
if(!(tempfile = cli_gentemp(NULL))) {
free(section_hdr);
free(src);
return CL_EMEM;
}
if((ndesc = open(tempfile, O_RDWR|O_CREAT|O_TRUNC|O_BINARY, S_IRWXU)) < 0) {
cli_dbgmsg("FSG: Can't create file %s\n", tempfile);
free(tempfile);
free(section_hdr);
free(src);
free(dest);
return CL_EIO;
}
switch (unfsg_200(newesi - EC32(section_hdr[i + 1].VirtualAddress) + src, dest, ssize + EC32(section_hdr[i + 1].VirtualAddress) - newesi, dsize, newedi, EC32(optional_hdr32.ImageBase), newedx, ndesc)) {
case 1: /* Everything OK */
cli_dbgmsg("FSG: Unpacked and rebuilt executable saved in %s\n", tempfile);
free(src);
free(dest);
fsync(ndesc);
lseek(ndesc, 0, SEEK_SET);
cli_dbgmsg("***** Scanning rebuilt PE file *****\n");
if(cli_magic_scandesc(ndesc, ctx) == CL_VIRUS) {
free(section_hdr);
close(ndesc);
if(!cli_leavetemps_flag)
unlink(tempfile);
free(tempfile);
return CL_VIRUS;
}
close(ndesc);
if(!cli_leavetemps_flag)
unlink(tempfile);
free(tempfile);
free(section_hdr);
return CL_CLEAN;
case 0: /* We've got an unpacked buffer, no exe though */
cli_dbgmsg("FSG: FSG: Successfully decompressed\n");
close(ndesc);
unlink(tempfile);
free(tempfile);
found = 0;
upx_success = 1;
break; /* Go and scan the buffer! */
default: /* Everything gone wrong */
cli_dbgmsg("FSG: Unpacking failed\n");
close(ndesc);
unlink(tempfile); /* It's empty anyway */
free(tempfile);
free(src);
free(dest);
break;
}
break; /* were done with 2 */
}
}
if(found && buff[0] == '\xbe' && cli_readint32(buff + 1) - EC32(optional_hdr32.ImageBase) < min) {
/* FSG support - v. 1.33 (thx trog for the many samples) */
ssize = EC32(section_hdr[i + 1].SizeOfRawData);
dsize = EC32(section_hdr[i].VirtualSize);
while(found) {
int gp, t, sectcnt = 0;
char *support;
uint32_t newesi, newedi, newebx, oldep;
struct SECTION *sections;
if(ctx->limits && ctx->limits->maxfilesize && (ssize > ctx->limits->maxfilesize || dsize > ctx->limits->maxfilesize)) {
cli_dbgmsg("FSG: Sizes exceeded (ssize: %u, dsize: %u, max: %lu)\n", ssize, dsize, ctx->limits->maxfilesize);
free(section_hdr);
if(BLOCKMAX) {
*ctx->virname = "PE.FSG.ExceededFileSize";
return CL_VIRUS;
} else {
return CL_CLEAN;
}
}
if(ssize <= 0x19 || dsize <= ssize) {
cli_dbgmsg("FSG: Size mismatch (ssize: %d, dsize: %d)\n", ssize, dsize);
free(section_hdr);
return CL_CLEAN;
}
if((gp = cli_readint32(buff + 1) - EC32(optional_hdr32.ImageBase)) >= (int) EC32(section_hdr[i + 1].PointerToRawData) || gp < 0) {
cli_dbgmsg("FSG: Support data out of padding area (vaddr: %d)\n", EC32(section_hdr[i].VirtualAddress));
break;
}
lseek(desc, gp, SEEK_SET);
gp = EC32(section_hdr[i + 1].PointerToRawData) - gp;
if(ctx->limits && ctx->limits->maxfilesize && (unsigned int) gp > ctx->limits->maxfilesize) {
cli_dbgmsg("FSG: Buffer size exceeded (size: %d, max: %lu)\n", gp, ctx->limits->maxfilesize);
free(section_hdr);
if(BLOCKMAX) {
*ctx->virname = "PE.FSG.ExceededFileSize";
return CL_VIRUS;
} else {
return CL_CLEAN;
}
}
if((support = (char *) cli_malloc(gp)) == NULL) {
free(section_hdr);
return CL_EMEM;
}
if(cli_readn(desc, support, gp) != gp) {
cli_dbgmsg("Can't read %d bytes from padding area\n", gp);
free(section_hdr);
free(support);
return CL_EIO;
}
newebx = cli_readint32(support) - EC32(optional_hdr32.ImageBase); /* Unused */
newedi = cli_readint32(support + 4) - EC32(optional_hdr32.ImageBase); /* 1st dest */
newesi = cli_readint32(support + 8) - EC32(optional_hdr32.ImageBase); /* Source */
if(newesi < EC32(section_hdr[i + 1].VirtualAddress) || newesi >= EC32(section_hdr[i + 1].VirtualAddress) + EC32(section_hdr[i + 1].SizeOfRawData)) {
cli_dbgmsg("FSG: Source buffer out of section bounds\n");
free(support);
break;
}
if(newedi != EC32(section_hdr[i].VirtualAddress)) {
cli_dbgmsg("FSG: Bad destination (is %x should be %x)\n", newedi, EC32(section_hdr[i].VirtualAddress));
free(support);
break;
}
/* Counting original sections */
for(t = 12; t < gp - 4; t += 4) {
uint32_t rva = cli_readint32(support+t);
if(!rva)
break;
rva -= EC32(optional_hdr32.ImageBase)+1;
sectcnt++;
if(rva % 0x1000)
/* FIXME: really need to bother? */
cli_dbgmsg("FSG: Original section %d is misaligned\n", sectcnt);
if(rva < EC32(section_hdr[i].VirtualAddress) || rva >= EC32(section_hdr[i].VirtualAddress)+EC32(section_hdr[i].VirtualSize)) {
cli_dbgmsg("FSG: Original section %d is out of bounds\n", sectcnt);
break;
}
}
if(t >= gp - 4 || cli_readint32(support + t)) {
free(support);
break;
}
if((sections = (struct SECTION *) cli_malloc((sectcnt + 1) * sizeof(struct SECTION))) == NULL) {
free(section_hdr);
free(support);
return CL_EMEM;
}
sections[0].rva = newedi;
for(t = 1; t <= sectcnt; t++)
sections[t].rva = cli_readint32(support + 8 + t * 4) - 1 -EC32(optional_hdr32.ImageBase);
free(support);
if((src = (char *) cli_malloc(ssize)) == NULL) {
free(section_hdr);
free(sections);
return CL_EMEM;
}
lseek(desc, EC32(section_hdr[i + 1].PointerToRawData), SEEK_SET);
if((unsigned int) cli_readn(desc, src, ssize) != ssize) {
cli_dbgmsg("Can't read raw data of section %d\n", i);
free(section_hdr);
free(sections);
free(src);
return CL_EIO;
}
if((dest = (char *) cli_calloc(dsize, sizeof(char))) == NULL) {
free(section_hdr);
free(src);
free(sections);
return CL_EMEM;
}
oldep = EC32(optional_hdr32.AddressOfEntryPoint) + 161 + 6 + cli_readint32(buff+163);
cli_dbgmsg("FSG: found old EP @%x\n", oldep);
if(!(tempfile = cli_gentemp(NULL))) {
free(section_hdr);
free(src);
free(dest);
free(sections);
return CL_EMEM;
}
if((ndesc = open(tempfile, O_RDWR|O_CREAT|O_TRUNC|O_BINARY, S_IRWXU)) < 0) {
cli_dbgmsg("FSG: Can't create file %s\n", tempfile);
free(tempfile);
free(section_hdr);
free(src);
free(dest);
free(sections);
return CL_EIO;
}
switch(unfsg_133(src + newesi - EC32(section_hdr[i + 1].VirtualAddress), dest, ssize + EC32(section_hdr[i + 1].VirtualAddress) - newesi, dsize, sections, sectcnt, EC32(optional_hdr32.ImageBase), oldep, ndesc)) {
case 1: /* Everything OK */
cli_dbgmsg("FSG: Unpacked and rebuilt executable saved in %s\n", tempfile);
free(src);
free(dest);
free(sections);
fsync(ndesc);
lseek(ndesc, 0, SEEK_SET);
cli_dbgmsg("***** Scanning rebuilt PE file *****\n");
if(cli_magic_scandesc(ndesc, ctx) == CL_VIRUS) {
free(section_hdr);
close(ndesc);
if(!cli_leavetemps_flag)
unlink(tempfile);
free(tempfile);
return CL_VIRUS;
}
close(ndesc);
if(!cli_leavetemps_flag)
unlink(tempfile);
free(tempfile);
free(section_hdr);
return CL_CLEAN;
case 0: /* We've got an unpacked buffer, no exe though */
cli_dbgmsg("FSG: FSG: Successfully decompressed\n");
close(ndesc);
unlink(tempfile);
free(tempfile);
free(sections);
found = 0;
upx_success = 1;
break; /* Go and scan the buffer! */
default: /* Everything gone wrong */
cli_dbgmsg("FSG: Unpacking failed\n");
close(ndesc);
unlink(tempfile); /* It's empty anyway */
free(tempfile);
free(src);
free(dest);
free(sections);
break;
}
break; /* were done with 1.33 */
}
}
/* FIXME: easy 2 hack */
if(found && buff[0] == '\xbb' && cli_readint32(buff + 1) - EC32(optional_hdr32.ImageBase) < min && buff[5] == '\xbf' && buff[10] == '\xbe') {
/* FSG support - v. 1.31 */
ssize = EC32(section_hdr[i + 1].SizeOfRawData);
dsize = EC32(section_hdr[i].VirtualSize);
while(found) {
int gp = cli_readint32(buff+1) - EC32(optional_hdr32.ImageBase), t, sectcnt = 0;
char *support;
uint32_t newesi = cli_readint32(buff+11) - EC32(optional_hdr32.ImageBase);
uint32_t newedi = cli_readint32(buff+6) - EC32(optional_hdr32.ImageBase);
uint32_t oldep = EC32(optional_hdr32.AddressOfEntryPoint);
struct SECTION *sections;
if (oldep <= EC32(section_hdr[i + 1].VirtualAddress) || oldep > EC32(section_hdr[i + 1].VirtualAddress)+EC32(section_hdr[i + 1].SizeOfRawData) - 0xe0) {
cli_dbgmsg("FSG: EP not in section %d\n", i+1);
break;
}
oldep -= EC32(section_hdr[i + 1].VirtualAddress);
if(newesi < EC32(section_hdr[i + 1].VirtualAddress) || newesi >= EC32(section_hdr[i + 1].VirtualAddress) + EC32(section_hdr[i + 1].SizeOfRawData)) {
cli_dbgmsg("FSG: Source buffer out of section bounds\n");
break;
}
if(newedi != EC32(section_hdr[i].VirtualAddress)) {
cli_dbgmsg("FSG: Bad destination (is %x should be %x)\n", newedi, EC32(section_hdr[i].VirtualAddress));
break;
}
if(ctx->limits && ctx->limits->maxfilesize && (ssize > ctx->limits->maxfilesize || dsize > ctx->limits->maxfilesize)) {
cli_dbgmsg("FSG: Sizes exceeded (ssize: %u, dsize: %u, max: %lu)\n", ssize, dsize, ctx->limits->maxfilesize);
free(section_hdr);
if(BLOCKMAX) {
*ctx->virname = "PE.FSG.ExceededFileSize";
return CL_VIRUS;
} else {
return CL_CLEAN;
}
}
if(ssize <= 0x19 || dsize <= ssize) {
cli_dbgmsg("FSG: Size mismatch (ssize: %d, dsize: %d)\n", ssize, dsize);
free(section_hdr);
return CL_CLEAN;
}
if(gp >= (int) EC32(section_hdr[i + 1].PointerToRawData) || gp < 0) {
cli_dbgmsg("FSG: Support data out of padding area (newedi: %d, vaddr: %d)\n", newedi, EC32(section_hdr[i].VirtualAddress));
break;
}
lseek(desc, gp, SEEK_SET);
gp = EC32(section_hdr[i + 1].PointerToRawData) - gp;
if(ctx->limits && ctx->limits->maxfilesize && (unsigned int) gp > ctx->limits->maxfilesize) {
cli_dbgmsg("FSG: Buffer size exceeded (size: %d, max: %lu)\n", gp, ctx->limits->maxfilesize);
free(section_hdr);
if(BLOCKMAX) {
*ctx->virname = "PE.FSG.ExceededFileSize";
return CL_VIRUS;
} else {
return CL_CLEAN;
}
}
if((support = (char *) cli_malloc(gp)) == NULL) {
free(section_hdr);
return CL_EMEM;
}
if(cli_readn(desc, support, gp) != gp) {
cli_dbgmsg("Can't read %d bytes from padding area\n", gp);
free(section_hdr);
free(support);
return CL_EIO;
}
/* Counting original sections */
for(t = 0; t < gp - 2; t += 2) {
uint32_t rva = support[t]+256*support[t+1];
if (rva == 2 || rva == 1)
break;
rva = ((rva-2)<<12) - EC32(optional_hdr32.ImageBase);
sectcnt++;
if(rva < EC32(section_hdr[i].VirtualAddress) || rva >= EC32(section_hdr[i].VirtualAddress)+EC32(section_hdr[i].VirtualSize)) {
cli_dbgmsg("FSG: Original section %d is out of bounds\n", sectcnt);
break;
}
}
if(t >= gp-10 || cli_readint32(support + t + 6) != 2) {
free(support);
break;
}
if((sections = (struct SECTION *) cli_malloc((sectcnt + 1) * sizeof(struct SECTION))) == NULL) {
free(section_hdr);
free(support);
return CL_EMEM;
}
sections[0].rva = newedi;
for(t = 0; t <= sectcnt - 1; t++) {
sections[t+1].rva = (((support[t*2]+256*support[t*2+1])-2)<<12)-EC32(optional_hdr32.ImageBase);
}
free(support);
if((src = (char *) cli_malloc(ssize)) == NULL) {
free(section_hdr);
free(sections);
return CL_EMEM;
}
lseek(desc, EC32(section_hdr[i + 1].PointerToRawData), SEEK_SET);
if((unsigned int) cli_readn(desc, src, ssize) != ssize) {
cli_dbgmsg("Can't read raw data of section %d\n", i);
free(section_hdr);
free(sections);
free(src);
return CL_EIO;
}
if((dest = (char *) cli_calloc(dsize, sizeof(char))) == NULL) {
free(section_hdr);
free(src);
free(sections);
return CL_EMEM;
}
/* Better not increasing buff size any further, let's go the hard way */
gp = 0xda + 6*(buff[16]=='\xe8');
oldep = EC32(optional_hdr32.AddressOfEntryPoint) + gp + 6 + cli_readint32(src+gp+2+oldep);
cli_dbgmsg("FSG: found old EP @%x\n", oldep);
if(!(tempfile = cli_gentemp(NULL))) {
free(section_hdr);
free(src);
free(dest);
free(sections);
return CL_EMEM;
}
if((ndesc = open(tempfile, O_RDWR|O_CREAT|O_TRUNC|O_BINARY, S_IRWXU)) < 0) {
cli_dbgmsg("FSG: Can't create file %s\n", tempfile);
free(tempfile);
free(section_hdr);
free(src);
free(dest);
free(sections);
return CL_EIO;
}
switch(unfsg_133(src + newesi - EC32(section_hdr[i + 1].VirtualAddress), dest, ssize + EC32(section_hdr[i + 1].VirtualAddress) - newesi, dsize, sections, sectcnt, EC32(optional_hdr32.ImageBase), oldep, ndesc)) {
case 1: /* Everything OK */
cli_dbgmsg("FSG: Unpacked and rebuilt executable saved in %s\n", tempfile);
free(src);
free(dest);
free(sections);
fsync(ndesc);
lseek(ndesc, 0, SEEK_SET);
cli_dbgmsg("***** Scanning rebuilt PE file *****\n");
if(cli_magic_scandesc(ndesc, ctx) == CL_VIRUS) {
free(section_hdr);
close(ndesc);
if(!cli_leavetemps_flag)
unlink(tempfile);
free(tempfile);
return CL_VIRUS;
}
close(ndesc);
if(!cli_leavetemps_flag)
unlink(tempfile);
free(tempfile);
free(section_hdr);
return CL_CLEAN;
case 0: /* We've got an unpacked buffer, no exe though */
cli_dbgmsg("FSG: FSG: Successfully decompressed\n");
close(ndesc);
unlink(tempfile);
free(tempfile);
free(sections);
found = 0;
upx_success = 1;
break; /* Go and scan the buffer! */
default: /* Everything gone wrong */
cli_dbgmsg("FSG: Unpacking failed\n");
close(ndesc);
unlink(tempfile); /* It's empty anyway */
free(tempfile);
free(src);
free(dest);
free(sections);
break;
}
break; /* were done with 1.31 */
}
}
if(found) {
/* UPX support */
strncpy(sname, (char *) section_hdr[i].Name, 8);
sname[8] = 0;
cli_dbgmsg("UPX: Section %d name: %s\n", i, sname);
strncpy(sname, (char *) section_hdr[i + 1].Name, 8);
sname[8] = 0;
cli_dbgmsg("UPX: Section %d name: %s\n", i + 1, sname);
if(strncmp((char *) section_hdr[i].Name, "UPX0", 4) || strncmp((char *) section_hdr[i + 1].Name, "UPX1", 4))
cli_dbgmsg("UPX: Possibly hacked UPX section headers\n");
/* we assume (i + 1) is UPX1 */
ssize = EC32(section_hdr[i + 1].SizeOfRawData);
dsize = EC32(section_hdr[i].VirtualSize) + EC32(section_hdr[i + 1].VirtualSize);
if(ctx->limits && ctx->limits->maxfilesize && (ssize > ctx->limits->maxfilesize || dsize > ctx->limits->maxfilesize)) {
cli_dbgmsg("UPX: Sizes exceeded (ssize: %u, dsize: %u, max: %lu)\n", ssize, dsize , ctx->limits->maxfilesize);
free(section_hdr);
if(BLOCKMAX) {
*ctx->virname = "PE.UPX.ExceededFileSize";
return CL_VIRUS;
} else {
return CL_CLEAN;
}
}
if(ssize <= 0x19 || dsize <= ssize) { /* FIXME: What are reasonable values? */
cli_dbgmsg("UPX: Size mismatch (ssize: %d, dsize: %d)\n", ssize, dsize);
free(section_hdr);
return CL_CLEAN;
}
/* FIXME: use file operations in case of big files */
if((src = (char *) cli_malloc(ssize)) == NULL) {
free(section_hdr);
return CL_EMEM;
}
if(dsize > CLI_MAX_ALLOCATION) {
cli_errmsg("UPX: Too big value of dsize\n");
free(section_hdr);
free(src);
return CL_EMEM;
}
if((dest = (char *) cli_calloc(dsize + 1024 + nsections * 40, sizeof(char))) == NULL) {
free(section_hdr);
free(src);
return CL_EMEM;
}
lseek(desc, EC32(section_hdr[i + 1].PointerToRawData), SEEK_SET);
if((unsigned int) cli_readn(desc, src, ssize) != ssize) {
cli_dbgmsg("Can't read raw data of section %d\n", i);
free(section_hdr);
free(src);
free(dest);
return CL_EIO;
}
/* try to detect UPX code */
if(lseek(desc, ep, SEEK_SET) == -1) {
cli_dbgmsg("lseek() failed\n");
free(section_hdr);
free(src);
free(dest);
return CL_EIO;
}
if(cli_readn(desc, buff, 126) != 126) { /* i.e. 0x69 + 13 + 8 */
cli_dbgmsg("UPX: Can't read 126 bytes at 0x%x (%d)\n", ep, ep);
cli_dbgmsg("UPX/FSG: Broken or not UPX/FSG compressed file\n");
free(section_hdr);
free(src);
free(dest);
return CL_CLEAN;
} else {
if(cli_memstr(UPX_NRV2B, 24, buff + 0x69, 13) || cli_memstr(UPX_NRV2B, 24, buff + 0x69 + 8, 13)) {
cli_dbgmsg("UPX: Looks like a NRV2B decompression routine\n");
upxfn = upx_inflate2b;
} else if(cli_memstr(UPX_NRV2D, 24, buff + 0x69, 13) || cli_memstr(UPX_NRV2D, 24, buff + 0x69 + 8, 13)) {
cli_dbgmsg("UPX: Looks like a NRV2D decompression routine\n");
upxfn = upx_inflate2d;
} else if(cli_memstr(UPX_NRV2E, 24, buff + 0x69, 13) || cli_memstr(UPX_NRV2E, 24, buff + 0x69 + 8, 13)) {
cli_dbgmsg("UPX: Looks like a NRV2E decompression routine\n");
upxfn = upx_inflate2e;
}
}
if(upxfn) {
int skew = cli_readint32(buff + 2) - EC32(optional_hdr32.ImageBase) - EC32(section_hdr[i + 1].VirtualAddress);
if(buff[1] != '\xbe' || skew <= 0 || skew > 0xfff) { /* FIXME: legit skews?? */
skew = 0;
if(upxfn(src, ssize, dest, &dsize, EC32(section_hdr[i].VirtualAddress), EC32(section_hdr[i + 1].VirtualAddress), EC32(optional_hdr32.AddressOfEntryPoint)) >= 0)
upx_success = 1;
} else {
cli_dbgmsg("UPX: UPX1 seems skewed by %d bytes\n", skew);
if(upxfn(src + skew, ssize - skew, dest, &dsize, EC32(section_hdr[i].VirtualAddress), EC32(section_hdr[i + 1].VirtualAddress), EC32(optional_hdr32.AddressOfEntryPoint)-skew) >= 0 || upxfn(src, ssize, dest, &dsize, EC32(section_hdr[i].VirtualAddress), EC32(section_hdr[i + 1].VirtualAddress), EC32(optional_hdr32.AddressOfEntryPoint)) >= 0)
upx_success = 1;
}
if(upx_success)
cli_dbgmsg("UPX: Successfully decompressed\n");
else
cli_dbgmsg("UPX: Prefered decompressor failed\n");
}
if(!upx_success && upxfn != upx_inflate2b) {
if(upx_inflate2b(src, ssize, dest, &dsize, EC32(section_hdr[i].VirtualAddress), EC32(section_hdr[i + 1].VirtualAddress), EC32(optional_hdr32.AddressOfEntryPoint)) == -1 && upx_inflate2b(src + 0x15, ssize - 0x15, dest, &dsize, EC32(section_hdr[i].VirtualAddress), EC32(section_hdr[i + 1].VirtualAddress), EC32(optional_hdr32.AddressOfEntryPoint) - 0x15) == -1) {
cli_dbgmsg("UPX: NRV2B decompressor failed\n");
} else {
upx_success = 1;
cli_dbgmsg("UPX: Successfully decompressed with NRV2B\n");
}
}
if(!upx_success && upxfn != upx_inflate2d) {
if(upx_inflate2d(src, ssize, dest, &dsize, EC32(section_hdr[i].VirtualAddress), EC32(section_hdr[i + 1].VirtualAddress), EC32(optional_hdr32.AddressOfEntryPoint)) == -1 && upx_inflate2d(src + 0x15, ssize - 0x15, dest, &dsize, EC32(section_hdr[i].VirtualAddress), EC32(section_hdr[i + 1].VirtualAddress), EC32(optional_hdr32.AddressOfEntryPoint) - 0x15) == -1) {
cli_dbgmsg("UPX: NRV2D decompressor failed\n");
} else {
upx_success = 1;
cli_dbgmsg("UPX: Successfully decompressed with NRV2D\n");
}
}
if(!upx_success && upxfn != upx_inflate2e) {
if(upx_inflate2e(src, ssize, dest, &dsize, EC32(section_hdr[i].VirtualAddress), EC32(section_hdr[i + 1].VirtualAddress), EC32(optional_hdr32.AddressOfEntryPoint)) == -1 && upx_inflate2e(src + 0x15, ssize - 0x15, dest, &dsize, EC32(section_hdr[i].VirtualAddress), EC32(section_hdr[i + 1].VirtualAddress), EC32(optional_hdr32.AddressOfEntryPoint) - 0x15) == -1) {
cli_dbgmsg("UPX: NRV2E decompressor failed\n");
} else {
upx_success = 1;
cli_dbgmsg("UPX: Successfully decompressed with NRV2E\n");
}
}
if(!upx_success) {
cli_dbgmsg("UPX: All decompressors failed\n");
free(src);
free(dest);
}
}
if(upx_success) {
free(src);
free(section_hdr);
if(!(tempfile = cli_gentemp(NULL))) {
free(dest);
return CL_EMEM;
}
if((ndesc = open(tempfile, O_RDWR|O_CREAT|O_TRUNC|O_BINARY, S_IRWXU)) < 0) {
cli_dbgmsg("UPX/FSG: Can't create file %s\n", tempfile);
free(tempfile);
free(dest);
return CL_EIO;
}
if((unsigned int) write(ndesc, dest, dsize) != dsize) {
cli_dbgmsg("UPX/FSG: Can't write %d bytes\n", dsize);
free(tempfile);
free(dest);
close(ndesc);
return CL_EIO;
}
free(dest);
fsync(ndesc);
lseek(ndesc, 0, SEEK_SET);
if(cli_leavetemps_flag)
cli_dbgmsg("UPX/FSG: Decompressed data saved in %s\n", tempfile);
cli_dbgmsg("***** Scanning decompressed file *****\n");
if((ret = cli_magic_scandesc(ndesc, ctx)) == CL_VIRUS) {
close(ndesc);
if(!cli_leavetemps_flag)
unlink(tempfile);
free(tempfile);
return CL_VIRUS;
}
close(ndesc);
if(!cli_leavetemps_flag)
unlink(tempfile);
free(tempfile);
return ret;
}
}
/* Petite */
found = 2;
lseek(desc, ep, SEEK_SET);
if(cli_readn(desc, buff, 200) != 200) {
cli_dbgmsg("Can't read 200 bytes\n");
free(section_hdr);
return CL_EIO;
}
if(buff[0] != '\xb8' || (uint32_t) cli_readint32(buff + 1) != EC32(section_hdr[nsections - 1].VirtualAddress) + EC32(optional_hdr32.ImageBase)) {
if(nsections < 2 || buff[0] != '\xb8' || (uint32_t) cli_readint32(buff + 1) != EC32(section_hdr[nsections - 2].VirtualAddress) + EC32(optional_hdr32.ImageBase))
found = 0;
else
found = 1;
}
if(found) {
cli_dbgmsg("Petite: v2.%d compression detected\n", found);
if(cli_readint32(buff + 0x80) == 0x163c988d) {
cli_dbgmsg("Petite: level zero compression is not supported yet\n");
} else {
dsize = max - min;
if(ctx->limits && ctx->limits->maxfilesize && dsize > ctx->limits->maxfilesize) {
cli_dbgmsg("Petite: Size exceeded (dsize: %u, max: %lu)\n", dsize, ctx->limits->maxfilesize);
free(section_hdr);
if(BLOCKMAX) {
*ctx->virname = "PE.Petite.ExceededFileSize";
return CL_VIRUS;
} else {
return CL_CLEAN;
}
}
if((dest = (char *) cli_calloc(dsize, sizeof(char))) == NULL) {
cli_dbgmsg("Petite: Can't allocate %d bytes\n", dsize);
free(section_hdr);
return CL_EMEM;
}
for(i = 0 ; i < nsections; i++) {
if(section_hdr[i].SizeOfRawData) {
uint32_t offset = cli_rawaddr(EC32(section_hdr[i].VirtualAddress), section_hdr, nsections, &err);
if(err || lseek(desc, offset, SEEK_SET) == -1 || (unsigned int) cli_readn(desc, dest + EC32(section_hdr[i].VirtualAddress) - min, EC32(section_hdr[i].SizeOfRawData)) != EC32(section_hdr[i].SizeOfRawData)) {
free(section_hdr);
free(dest);
return CL_EIO;
}
}
}
if(!(tempfile = cli_gentemp(NULL))) {
free(dest);
free(section_hdr);
return CL_EMEM;
}
if((ndesc = open(tempfile, O_RDWR|O_CREAT|O_TRUNC|O_BINARY, S_IRWXU)) < 0) {
cli_dbgmsg("Petite: Can't create file %s\n", tempfile);
free(tempfile);
free(section_hdr);
free(dest);
return CL_EIO;
}
/* aCaB: Fixed to allow petite v2.1 unpacking (last section is a ghost) */
switch(petite_inflate2x_1to9(dest, min, max - min, section_hdr,
nsections - (found == 1 ? 1 : 0), EC32(optional_hdr32.ImageBase),
EC32(optional_hdr32.AddressOfEntryPoint), ndesc,
found, EC32(optional_hdr32.DataDirectory[2].VirtualAddress),
EC32(optional_hdr32.DataDirectory[2].Size))) {
case 1:
cli_dbgmsg("Petite: Unpacked and rebuilt executable saved in %s\n", tempfile);
cli_dbgmsg("***** Scanning rebuilt PE file *****\n");
break;
case 0:
cli_dbgmsg("Petite: Unpacked data saved in %s\n", tempfile);
break;
default:
cli_dbgmsg("Petite: Unpacking failed\n");
}
free(dest);
fsync(ndesc);
lseek(ndesc, 0, SEEK_SET);
if(cli_magic_scandesc(ndesc, ctx) == CL_VIRUS) {
free(section_hdr);
close(ndesc);
if(!cli_leavetemps_flag) {
unlink(tempfile);
free(tempfile);
} else {
free(tempfile);
}
return CL_VIRUS;
}
close(ndesc);
if(!cli_leavetemps_flag) {
unlink(tempfile);
free(tempfile);
} else {
free(tempfile);
}
}
}
/* PESpin 1.1 */
if(nsections > 1 &&
EC32(optional_hdr32.AddressOfEntryPoint) >= EC32(section_hdr[nsections - 1].VirtualAddress) &&
EC32(optional_hdr32.AddressOfEntryPoint) < EC32(section_hdr[nsections - 1].VirtualAddress) + EC32(section_hdr[nsections - 1].SizeOfRawData) - 0x3217 - 4 &&
memcmp(buff+4, "\xe8\x00\x00\x00\x00\x8b\x1c\x24\x83\xc3", 10) == 0) {
char *spinned;
if((spinned = (char *) cli_malloc(fsize)) == NULL) {
free(section_hdr);
return CL_EMEM;
}
lseek(desc, 0, SEEK_SET);
if((size_t) cli_readn(desc, spinned, fsize) != fsize) {
cli_dbgmsg("PESpin: Can't read %d bytes\n", fsize);
free(spinned);
free(section_hdr);
return CL_EIO;
}
if(!(tempfile = cli_gentemp(NULL))) {
free(spinned);
free(section_hdr);
return CL_EMEM;
}
if((ndesc = open(tempfile, O_RDWR|O_CREAT|O_TRUNC|O_BINARY, S_IRWXU)) < 0) {
cli_dbgmsg("PESpin: Can't create file %s\n", tempfile);
free(tempfile);
free(spinned);
free(section_hdr);
return CL_EIO;
}
if(!unspin(spinned, fsize, section_hdr, nsections - 1, EC32(optional_hdr32.AddressOfEntryPoint), ndesc)) {
free(spinned);
cli_dbgmsg("PESpin: Unpacked and rebuilt executable saved in %s\n", tempfile);
fsync(ndesc);
lseek(ndesc, 0, SEEK_SET);
if(cli_magic_scandesc(ndesc, ctx) == CL_VIRUS) {
free(section_hdr);
close(ndesc);
if(!cli_leavetemps_flag) {
unlink(tempfile);
free(tempfile);
} else {
free(tempfile);
}
return CL_VIRUS;
}
} else {
free(spinned);
cli_dbgmsg("PESpin: Rebuilding failed\n");
}
close(ndesc);
if(!cli_leavetemps_flag) {
unlink(tempfile);
free(tempfile);
} else {
free(tempfile);
}
}
/* yC 1.3 */
if(nsections > 1 &&
EC32(optional_hdr32.AddressOfEntryPoint) == EC32(section_hdr[nsections - 1].VirtualAddress) + 0x60 &&
memcmp(buff, "\x55\x8B\xEC\x53\x56\x57\x60\xE8\x00\x00\x00\x00\x5D\x81\xED\x6C\x28\x40\x00\xB9\x5D\x34\x40\x00\x81\xE9\xC6\x28\x40\x00\x8B\xD5\x81\xC2\xC6\x28\x40\x00\x8D\x3A\x8B\xF7\x33\xC0\xEB\x04\x90\xEB\x01\xC2\xAC", 51) == 0) {
char *spinned;
if ( fsize >= EC32(section_hdr[nsections - 1].PointerToRawData) + 0xC6 + 0xb97 ) { /* size check on yC sect */
if((spinned = (char *) cli_malloc(fsize)) == NULL) {
free(section_hdr);
return CL_EMEM;
}
lseek(desc, 0, SEEK_SET);
if((size_t) cli_readn(desc, spinned, fsize) != fsize) {
cli_dbgmsg("yC: Can't read %d bytes\n", fsize);
free(spinned);
free(section_hdr);
return CL_EIO;
}
if(!(tempfile = cli_gentemp(NULL))) {
free(spinned);
free(section_hdr);
return CL_EMEM;
}
if((ndesc = open(tempfile, O_RDWR|O_CREAT|O_TRUNC|O_BINARY, S_IRWXU)) < 0) {
cli_dbgmsg("yC: Can't create file %s\n", tempfile);
free(tempfile);
free(spinned);
free(section_hdr);
return CL_EIO;
}
if(!yc_decrypt(spinned, fsize, section_hdr, nsections-1, e_lfanew, ndesc)) {
free(spinned);
cli_dbgmsg("yC: Unpacked and rebuilt executable saved in %s\n", tempfile);
fsync(ndesc);
lseek(ndesc, 0, SEEK_SET);
if(cli_magic_scandesc(ndesc, ctx) == CL_VIRUS) {
free(section_hdr);
close(ndesc);
if(!cli_leavetemps_flag) {
unlink(tempfile);
free(tempfile);
} else {
free(tempfile);
}
return CL_VIRUS;
}
} else {
free(spinned);
cli_dbgmsg("yC: Rebuilding failed\n");
}
close(ndesc);
if(!cli_leavetemps_flag) {
unlink(tempfile);
free(tempfile);
} else {
free(tempfile);
}
}
}
/* WWPack */
if(nsections > 1 &&
EC32(section_hdr[nsections-1].SizeOfRawData)>0x2b1 &&
EC32(optional_hdr32.AddressOfEntryPoint) == EC32(section_hdr[nsections - 1].VirtualAddress) &&
EC32(section_hdr[nsections - 1].VirtualAddress)+EC32(section_hdr[nsections - 1].SizeOfRawData) == max &&
memcmp(buff, "\x53\x55\x8b\xe8\x33\xdb\xeb", 7) == 0 &&
memcmp(buff+0x68, "\xe8\x00\x00\x00\x00\x58\x2d\x6d\x00\x00\x00\x50\x60\x33\xc9\x50\x58\x50\x50", 19) == 0) {
uint32_t headsize=EC32(section_hdr[nsections - 1].PointerToRawData);
char *dest, *wwp;
for(i = 0 ; i < (unsigned int)nsections-1; i++) {
uint32_t offset = cli_rawaddr(EC32(section_hdr[i].VirtualAddress), section_hdr, nsections, &err);
if (!err && offset<headsize) headsize=offset;
}
dsize = max-min+headsize-EC32(section_hdr[nsections - 1].SizeOfRawData);
if(ctx->limits && ctx->limits->maxfilesize && dsize > ctx->limits->maxfilesize) {
cli_dbgmsg("WWPack: Size exceeded (dsize: %u, max: %lu)\n", dsize, ctx->limits->maxfilesize);
free(section_hdr);
if(BLOCKMAX) {
*ctx->virname = "PE.WWPack.ExceededFileSize";
return CL_VIRUS;
} else {
return CL_CLEAN;
}
}
if((dest = (char *) cli_calloc(dsize, sizeof(char))) == NULL) {
cli_dbgmsg("WWPack: Can't allocate %d bytes\n", dsize);
free(section_hdr);
return CL_EMEM;
}
memset(dest, 0, dsize);
lseek(desc, 0, SEEK_SET);
if((size_t) cli_readn(desc, dest, headsize) != headsize) {
cli_dbgmsg("WWPack: Can't read %d bytes from headers\n", headsize);
free(dest);
free(section_hdr);
return CL_EIO;
}
for(i = 0 ; i < (unsigned int)nsections-1; i++) {
if(section_hdr[i].SizeOfRawData) {
uint32_t offset = cli_rawaddr(EC32(section_hdr[i].VirtualAddress), section_hdr, nsections, &err);
if(err || lseek(desc, offset, SEEK_SET) == -1 || (unsigned int) cli_readn(desc, dest + headsize + EC32(section_hdr[i].VirtualAddress) - min, EC32(section_hdr[i].SizeOfRawData)) != EC32(section_hdr[i].SizeOfRawData)) {
free(dest);
free(section_hdr);
return CL_EIO;
}
}
}
if((wwp = (char *) cli_calloc(EC32(section_hdr[nsections - 1].SizeOfRawData), sizeof(char))) == NULL) {
cli_dbgmsg("WWPack: Can't allocate %d bytes\n", EC32(section_hdr[nsections - 1].SizeOfRawData));
free(dest);
free(section_hdr);
return CL_EMEM;
}
lseek(desc, EC32(section_hdr[nsections - 1].PointerToRawData), SEEK_SET);
if((size_t) cli_readn(desc, wwp, EC32(section_hdr[nsections - 1].SizeOfRawData)) != EC32(section_hdr[nsections - 1].SizeOfRawData)) {
cli_dbgmsg("WWPack: Can't read %d bytes from wwpack sect\n", EC32(section_hdr[nsections - 1].SizeOfRawData));
free(dest);
free(wwp);
free(section_hdr);
return CL_EIO;
}
if (!wwunpack(dest, dsize, headsize, min, EC32(section_hdr[nsections-1].VirtualAddress), e_lfanew, wwp, EC32(section_hdr[nsections - 1].SizeOfRawData), nsections-1)) {
free(wwp);
if(!(tempfile = cli_gentemp(NULL))) {
free(dest);
free(section_hdr);
return CL_EMEM;
}
if((ndesc = open(tempfile, O_RDWR|O_CREAT|O_TRUNC|O_BINARY, S_IRWXU)) < 0) {
cli_dbgmsg("WWPack: Can't create file %s\n", tempfile);
free(tempfile);
free(dest);
free(section_hdr);
return CL_EIO;
}
if((unsigned int) write(ndesc, dest, dsize) != dsize) {
cli_dbgmsg("WWPack: Can't write %d bytes\n", dsize);
close(ndesc);
free(tempfile);
free(dest);
free(section_hdr);
return CL_EIO;
}
free(dest);
if (cli_leavetemps_flag)
cli_dbgmsg("WWPack: Unpacked and rebuilt executable saved in %s\n", tempfile);
else
cli_dbgmsg("WWPack: Unpacked and rebuilt executable\n");
fsync(ndesc);
lseek(ndesc, 0, SEEK_SET);
if(cli_magic_scandesc(ndesc, ctx) == CL_VIRUS) {
free(section_hdr);
close(ndesc);
if(!cli_leavetemps_flag)
unlink(tempfile);
free(tempfile);
return CL_VIRUS;
}
close(ndesc);
if(!cli_leavetemps_flag)
unlink(tempfile);
free(tempfile);
} else {
free(wwp);
free(dest);
cli_dbgmsg("WWPpack: Decompression failed\n");
}
}
/* to be continued ... */
free(section_hdr);
return CL_CLEAN;
}
int cli_peheader(int desc, struct cli_exe_info *peinfo)
{
uint16_t e_magic; /* DOS signature ("MZ") */
uint32_t e_lfanew; /* address of new exe header */
uint32_t min = 0, max = 0;
struct pe_image_file_hdr file_hdr;
struct pe_image_optional_hdr32 optional_hdr32;
struct pe_image_optional_hdr64 optional_hdr64;
struct pe_image_section_hdr *section_hdr;
struct stat sb;
int i;
unsigned int err, pe_plus = 0;
cli_dbgmsg("in cli_peheader\n");
if(cli_readn(desc, &e_magic, sizeof(e_magic)) != sizeof(e_magic)) {
cli_dbgmsg("Can't read DOS signature\n");
return -1;
}
if(EC16(e_magic) != IMAGE_DOS_SIGNATURE && EC16(e_magic) != IMAGE_DOS_SIGNATURE_OLD) {
cli_dbgmsg("Invalid DOS signature\n");
return -1;
}
lseek(desc, 58, SEEK_CUR); /* skip to the end of the DOS header */
if(cli_readn(desc, &e_lfanew, sizeof(e_lfanew)) != sizeof(e_lfanew)) {
cli_dbgmsg("Can't read new header address\n");
/* truncated header? */
return -1;
}
e_lfanew = EC32(e_lfanew);
if(!e_lfanew) {
cli_dbgmsg("Not a PE file\n");
return -1;
}
if(lseek(desc, e_lfanew, SEEK_SET) < 0) {
/* probably not a PE file */
cli_dbgmsg("Can't lseek to e_lfanew\n");
return -1;
}
if(cli_readn(desc, &file_hdr, sizeof(struct pe_image_file_hdr)) != sizeof(struct pe_image_file_hdr)) {
/* bad information in e_lfanew - probably not a PE file */
cli_dbgmsg("Can't read file header\n");
return -1;
}
if(EC32(file_hdr.Magic) != IMAGE_NT_SIGNATURE) {
cli_dbgmsg("Invalid PE signature (probably NE file)\n");
return -1;
}
peinfo->nsections = EC16(file_hdr.NumberOfSections);
if(EC16(file_hdr.SizeOfOptionalHeader) != sizeof(struct pe_image_optional_hdr32)) {
if(EC16(file_hdr.SizeOfOptionalHeader) == sizeof(struct pe_image_optional_hdr64)) {
pe_plus = 1;
} else {
cli_dbgmsg("Incorrect value of SizeOfOptionalHeader\n");
return -1;
}
}
if(!pe_plus) { /* PE */
cli_dbgmsg("File format: PE\n");
if(cli_readn(desc, &optional_hdr32, sizeof(struct pe_image_optional_hdr32)) != sizeof(struct pe_image_optional_hdr32)) {
cli_dbgmsg("Can't optional file header\n");
return -1;
}
} else { /* PE+ */
cli_dbgmsg("File format: PE32+\n");
if(cli_readn(desc, &optional_hdr64, sizeof(struct pe_image_optional_hdr64)) != sizeof(struct pe_image_optional_hdr64)) {
cli_dbgmsg("Can't optional file header\n");
return -1;
}
}
peinfo->section = (struct cli_exe_section *) cli_calloc(peinfo->nsections, sizeof(struct cli_exe_section));
if(!peinfo->section) {
cli_dbgmsg("Can't allocate memory for section headers\n");
return -1;
}
if(fstat(desc, &sb) == -1) {
cli_dbgmsg("fstat failed\n");
free(peinfo->section);
return -1;
}
section_hdr = (struct pe_image_section_hdr *) cli_calloc(peinfo->nsections, sizeof(struct pe_image_section_hdr));
if(!section_hdr) {
cli_dbgmsg("Can't allocate memory for section headers\n");
free(peinfo->section);
return -1;
}
for(i = 0; i < peinfo->nsections; i++) {
if(cli_readn(desc, &section_hdr[i], sizeof(struct pe_image_section_hdr)) != sizeof(struct pe_image_section_hdr)) {
cli_dbgmsg("Can't read section header\n");
cli_dbgmsg("Possibly broken PE file\n");
free(section_hdr);
free(peinfo->section);
return -1;
}
peinfo->section[i].rva = EC32(section_hdr[i].VirtualAddress);
peinfo->section[i].vsz = EC32(section_hdr[i].VirtualSize);
peinfo->section[i].raw = EC32(section_hdr[i].PointerToRawData);
peinfo->section[i].rsz = EC32(section_hdr[i].SizeOfRawData);
if(!i) {
min = EC32(section_hdr[i].VirtualAddress);
max = EC32(section_hdr[i].VirtualAddress) + EC32(section_hdr[i].SizeOfRawData);
} else {
if(EC32(section_hdr[i].VirtualAddress) < min)
min = EC32(section_hdr[i].VirtualAddress);
if(EC32(section_hdr[i].VirtualAddress) + EC32(section_hdr[i].SizeOfRawData) > max)
max = EC32(section_hdr[i].VirtualAddress) + EC32(section_hdr[i].SizeOfRawData);
}
}
if(pe_plus)
peinfo->ep = EC32(optional_hdr64.AddressOfEntryPoint);
else
peinfo->ep = EC32(optional_hdr32.AddressOfEntryPoint);
if(peinfo->ep >= min && !(peinfo->ep = cli_rawaddr(peinfo->ep, section_hdr, peinfo->nsections, &err)) && err) {
cli_dbgmsg("Possibly broken PE file\n");
free(section_hdr);
free(peinfo->section);
return -1;
}
free(section_hdr);
return 0;
}