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1448 lines
44 KiB
1448 lines
44 KiB
/*
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* Copyright (C) 2004 - 2005 Tomasz Kojm <tkojm@clamav.net>
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*
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* With additions from aCaB <acab@clamav.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#if HAVE_CONFIG_H
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#include "clamav-config.h"
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#endif
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#include <stdio.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <time.h>
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#include "cltypes.h"
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#include "clamav.h"
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#include "others.h"
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#include "pe.h"
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#include "upx.h"
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#include "petite.h"
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#include "fsg.h"
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#include "scanners.h"
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#include "rebuildpe.h"
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#include "str.h"
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#define IMAGE_DOS_SIGNATURE 0x5a4d /* MZ */
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#define IMAGE_DOS_SIGNATURE_OLD 0x4d5a /* ZM */
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#define IMAGE_NT_SIGNATURE 0x00004550
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#define IMAGE_OPTIONAL_SIGNATURE 0x010b
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#define DETECT_BROKEN (options & CL_SCAN_BLOCKBROKEN)
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#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"
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#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"
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#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"
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#if WORDS_BIGENDIAN == 0
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#define EC16(v) (v)
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#define EC32(v) (v)
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#else
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static inline uint16_t EC16(uint16_t v)
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{
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return ((v >> 8) + (v << 8));
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}
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static inline uint32_t EC32(uint32_t v)
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{
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return ((v >> 24) | ((v & 0x00FF0000) >> 8) | ((v & 0x0000FF00) << 8) | (v << 24));
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}
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#endif
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extern short cli_leavetemps_flag;
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static uint32_t cli_rawaddr(uint32_t rva, struct pe_image_section_hdr *shp, uint16_t nos, unsigned int *err)
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{
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int i, found = 0;
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for(i = 0; i < nos; i++) {
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if(EC32(shp[i].VirtualAddress) <= rva && EC32(shp[i].VirtualAddress) + EC32(shp[i].SizeOfRawData) > rva) {
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found = 1;
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break;
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}
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}
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if(!found) {
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cli_dbgmsg("Can't calculate raw address from RVA 0x%x\n", rva);
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*err = 1;
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return 0;
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}
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*err = 0;
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return rva - EC32(shp[i].VirtualAddress) + EC32(shp[i].PointerToRawData);
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}
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/*
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static int cli_ddump(int desc, int offset, int size, const char *file)
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{
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int pos, ndesc, bread, sum = 0;
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char buff[FILEBUFF];
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cli_dbgmsg("in ddump()\n");
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if((pos = lseek(desc, 0, SEEK_CUR)) == -1) {
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cli_dbgmsg("Invalid descriptor\n");
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return -1;
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}
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if(lseek(desc, offset, SEEK_SET) == -1) {
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cli_dbgmsg("lseek() failed\n");
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lseek(desc, pos, SEEK_SET);
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return -1;
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}
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if((ndesc = open(file, O_WRONLY|O_CREAT|O_TRUNC, S_IRWXU)) < 0) {
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cli_dbgmsg("Can't create file %s\n", file);
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lseek(desc, pos, SEEK_SET);
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return -1;
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}
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while((bread = read(desc, buff, FILEBUFF)) > 0) {
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if(sum + bread >= size) {
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if(write(ndesc, buff, size - sum) == -1) {
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cli_dbgmsg("Can't write to file\n");
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lseek(desc, pos, SEEK_SET);
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close(ndesc);
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unlink(file);
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return -1;
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}
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break;
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} else {
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if(write(ndesc, buff, bread) == -1) {
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cli_dbgmsg("Can't write to file\n");
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lseek(desc, pos, SEEK_SET);
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close(ndesc);
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unlink(file);
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return -1;
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}
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}
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sum += bread;
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}
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close(ndesc);
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lseek(desc, pos, SEEK_SET);
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return 0;
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}
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*/
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int cli_scanpe(int desc, const char **virname, long int *scanned, const struct cl_node *root, const struct cl_limits *limits, unsigned int options, unsigned int arec, unsigned int mrec)
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{
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uint16_t e_magic; /* DOS signature ("MZ") */
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uint16_t nsections;
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uint32_t e_lfanew; /* address of new exe header */
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uint32_t ep; /* entry point (raw) */
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time_t timestamp;
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struct pe_image_file_hdr file_hdr;
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struct pe_image_optional_hdr optional_hdr;
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struct pe_image_section_hdr *section_hdr;
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struct stat sb;
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char sname[9], buff[4096], *tempfile;
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unsigned int i, found, upx_success = 0, min = 0, max = 0, err, broken = 0;
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unsigned int ssize = 0, dsize = 0, dll = 0;
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int (*upxfn)(char *, int , char *, int *, uint32_t, uint32_t, uint32_t) = NULL;
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char *src = NULL, *dest = NULL;
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int ndesc, ret;
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if(read(desc, &e_magic, sizeof(e_magic)) != sizeof(e_magic)) {
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cli_dbgmsg("Can't read DOS signature\n");
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return CL_CLEAN;
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}
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if(EC16(e_magic) != IMAGE_DOS_SIGNATURE && EC16(e_magic) != IMAGE_DOS_SIGNATURE_OLD) {
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cli_dbgmsg("Invalid DOS signature\n");
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return CL_CLEAN;
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}
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lseek(desc, 58, SEEK_CUR); /* skip to the end of the DOS header */
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if(read(desc, &e_lfanew, sizeof(e_lfanew)) != sizeof(e_lfanew)) {
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cli_dbgmsg("Can't read new header address\n");
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/* truncated header? */
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if(DETECT_BROKEN) {
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if(virname)
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*virname = "Broken.Executable";
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return CL_VIRUS;
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}
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return CL_CLEAN;
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}
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e_lfanew = EC32(e_lfanew);
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cli_dbgmsg("e_lfanew == %d\n", e_lfanew);
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if(!e_lfanew) {
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cli_dbgmsg("Not a PE file\n");
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return CL_CLEAN;
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}
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if(lseek(desc, e_lfanew, SEEK_SET) < 0) {
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/* probably not a PE file */
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cli_dbgmsg("Can't lseek to e_lfanew\n");
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return CL_CLEAN;
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}
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if(read(desc, &file_hdr, sizeof(struct pe_image_file_hdr)) != sizeof(struct pe_image_file_hdr)) {
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/* bad information in e_lfanew - probably not a PE file */
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cli_dbgmsg("Can't read file header\n");
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return CL_CLEAN;
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}
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if(EC32(file_hdr.Magic) != IMAGE_NT_SIGNATURE) {
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cli_dbgmsg("Invalid PE signature (probably NE file)\n");
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return CL_CLEAN;
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}
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if(EC16(file_hdr.Characteristics) & 0x2000) {
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cli_dbgmsg("File type: DLL\n");
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dll = 1;
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} else if(EC16(file_hdr.Characteristics) & 0x01) {
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cli_dbgmsg("File type: Executable\n");
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}
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switch(EC16(file_hdr.Machine)) {
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case 0x14c:
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cli_dbgmsg("Machine type: 80386\n");
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break;
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case 0x014d:
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cli_dbgmsg("Machine type: 80486\n");
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break;
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case 0x014e:
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cli_dbgmsg("Machine type: 80586\n");
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break;
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case 0x162:
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cli_dbgmsg("Machine type: R3000\n");
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break;
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case 0x166:
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cli_dbgmsg("Machine type: R4000\n");
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break;
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case 0x168:
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cli_dbgmsg("Machine type: R10000\n");
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break;
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case 0x184:
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cli_dbgmsg("Machine type: DEC Alpha AXP\n");
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break;
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case 0x284:
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cli_dbgmsg("Machine type: DEC Alpha AXP 64bit\n");
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break;
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case 0x1f0:
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cli_dbgmsg("Machine type: PowerPC\n");
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break;
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case 0x200:
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cli_dbgmsg("Machine type: IA64\n");
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break;
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case 0x268:
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cli_dbgmsg("Machine type: M68k\n");
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break;
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case 0x266:
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cli_dbgmsg("Machine type: MIPS16\n");
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break;
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case 0x366:
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cli_dbgmsg("Machine type: MIPS+FPU\n");
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break;
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case 0x466:
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cli_dbgmsg("Machine type: MIPS16+FPU\n");
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break;
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case 0x1a2:
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cli_dbgmsg("Machine type: Hitachi SH3\n");
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break;
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case 0x1a6:
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cli_dbgmsg("Machine type: Hitachi SH4\n");
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break;
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case 0x1c0:
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cli_dbgmsg("Machine type: ARM\n");
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break;
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case 0x1c2:
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cli_dbgmsg("Machine type: THUMB\n");
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break;
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default:
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cli_warnmsg("Unknown machine type in PE header (0x%x)\n", EC16(file_hdr.Machine));
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}
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nsections = EC16(file_hdr.NumberOfSections);
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if(nsections < 1) {
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if(DETECT_BROKEN) {
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if(virname)
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*virname = "Broken.Executable";
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return CL_VIRUS;
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}
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cli_warnmsg("PE file contains no sections\n");
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return CL_CLEAN;
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}
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cli_dbgmsg("NumberOfSections: %d\n", nsections);
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timestamp = (time_t) EC32(file_hdr.TimeDateStamp);
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cli_dbgmsg("TimeDateStamp: %s", ctime(×tamp));
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cli_dbgmsg("SizeOfOptionalHeader: %d\n", EC16(file_hdr.SizeOfOptionalHeader));
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if(EC16(file_hdr.SizeOfOptionalHeader) != sizeof(struct pe_image_optional_hdr)) {
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cli_warnmsg("Broken PE header detected.\n");
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if(DETECT_BROKEN) {
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if(virname)
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*virname = "Broken.Executable";
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return CL_VIRUS;
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}
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return CL_CLEAN;
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}
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if(read(desc, &optional_hdr, sizeof(struct pe_image_optional_hdr)) != sizeof(struct pe_image_optional_hdr)) {
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cli_dbgmsg("Can't optional file header\n");
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if(DETECT_BROKEN) {
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if(virname)
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*virname = "Broken.Executable";
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return CL_VIRUS;
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}
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return CL_CLEAN;
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}
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cli_dbgmsg("MajorLinkerVersion: %d\n", optional_hdr.MajorLinkerVersion);
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cli_dbgmsg("MinorLinkerVersion: %d\n", optional_hdr.MinorLinkerVersion);
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cli_dbgmsg("SizeOfCode: %d\n", EC32(optional_hdr.SizeOfCode));
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cli_dbgmsg("SizeOfInitializedData: %d\n", EC32(optional_hdr.SizeOfInitializedData));
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cli_dbgmsg("SizeOfUninitializedData: %d\n", EC32(optional_hdr.SizeOfUninitializedData));
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cli_dbgmsg("AddressOfEntryPoint: 0x%x\n", EC32(optional_hdr.AddressOfEntryPoint));
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cli_dbgmsg("SectionAlignment: %d\n", EC32(optional_hdr.SectionAlignment));
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cli_dbgmsg("FileAlignment: %d\n", EC32(optional_hdr.FileAlignment));
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cli_dbgmsg("MajorSubsystemVersion: %d\n", EC16(optional_hdr.MajorSubsystemVersion));
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cli_dbgmsg("MinorSubsystemVersion: %d\n", EC16(optional_hdr.MinorSubsystemVersion));
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cli_dbgmsg("SizeOfImage: %d\n", EC32(optional_hdr.SizeOfImage));
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cli_dbgmsg("SizeOfHeaders: %d\n", EC32(optional_hdr.SizeOfHeaders));
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switch(EC16(optional_hdr.Subsystem)) {
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case 0:
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cli_dbgmsg("Subsystem: Unknown\n");
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break;
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case 1:
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cli_dbgmsg("Subsystem: Native (a driver ?)\n");
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break;
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case 2:
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cli_dbgmsg("Subsystem: Win32 GUI\n");
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break;
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case 3:
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cli_dbgmsg("Subsystem: Win32 console\n");
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break;
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case 5:
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cli_dbgmsg("Subsystem: OS/2 console\n");
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break;
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case 7:
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cli_dbgmsg("Subsystem: POSIX console\n");
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break;
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case 8:
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cli_dbgmsg("Subsystem: Native Win9x driver\n");
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break;
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case 9:
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cli_dbgmsg("Subsystem: WinCE GUI\n");
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break;
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case 10:
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cli_dbgmsg("Subsystem: EFI application\n");
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break;
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case 11:
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cli_dbgmsg("Subsystem: EFI driver\n");
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break;
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case 12:
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cli_dbgmsg("Subsystem: EFI runtime driver\n");
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break;
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default:
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cli_warnmsg("Unknown subsystem in PE header (0x%x)\n", EC16(optional_hdr.Subsystem));
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}
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cli_dbgmsg("NumberOfRvaAndSizes: %d\n", EC32(optional_hdr.NumberOfRvaAndSizes));
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cli_dbgmsg("------------------------------------\n");
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if(fstat(desc, &sb) == -1) {
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cli_dbgmsg("fstat failed\n");
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return CL_EIO;
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}
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section_hdr = (struct pe_image_section_hdr *) cli_calloc(nsections, sizeof(struct pe_image_section_hdr));
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if(!section_hdr) {
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cli_dbgmsg("Can't allocate memory for section headers\n");
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return CL_EMEM;
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}
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for(i = 0; i < nsections; i++) {
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if(read(desc, §ion_hdr[i], sizeof(struct pe_image_section_hdr)) != sizeof(struct pe_image_section_hdr)) {
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cli_dbgmsg("Can't read section header\n");
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cli_dbgmsg("Possibly broken PE file\n");
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free(section_hdr);
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if(DETECT_BROKEN) {
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if(virname)
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*virname = "Broken.Executable";
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return CL_VIRUS;
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}
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return CL_CLEAN;
|
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}
|
|
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strncpy(sname, section_hdr[i].Name, 8);
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sname[8] = 0;
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cli_dbgmsg("Section %d\n", i);
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cli_dbgmsg("Section name: %s\n", sname);
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cli_dbgmsg("VirtualSize: %d\n", EC32(section_hdr[i].VirtualSize));
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cli_dbgmsg("VirtualAddress: 0x%x\n", EC32(section_hdr[i].VirtualAddress));
|
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cli_dbgmsg("SizeOfRawData: %d\n", EC32(section_hdr[i].SizeOfRawData));
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cli_dbgmsg("PointerToRawData: 0x%x (%d)\n", EC32(section_hdr[i].PointerToRawData), EC32(section_hdr[i].PointerToRawData));
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|
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if(EC32(section_hdr[i].Characteristics) & 0x20) {
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cli_dbgmsg("Section contains executable code\n");
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|
|
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if(EC32(section_hdr[i].VirtualSize) < EC32(section_hdr[i].SizeOfRawData)) {
|
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cli_dbgmsg("Section contains free space\n");
|
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/*
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cli_dbgmsg("Dumping %d bytes\n", section_hdr.SizeOfRawData - section_hdr.VirtualSize);
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ddump(desc, section_hdr.PointerToRawData + section_hdr.VirtualSize, section_hdr.SizeOfRawData - section_hdr.VirtualSize, cli_gentemp(NULL));
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*/
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|
|
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}
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}
|
|
|
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if(EC32(section_hdr[i].Characteristics) & 0x20000000)
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cli_dbgmsg("Section's memory is executable\n");
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|
|
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if(EC32(section_hdr[i].Characteristics) & 0x80000000)
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cli_dbgmsg("Section's memory is writeable\n");
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|
|
|
cli_dbgmsg("------------------------------------\n");
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|
|
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if(EC32(section_hdr[i].PointerToRawData) + EC32(section_hdr[i].SizeOfRawData) > (unsigned long int) sb.st_size) {
|
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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), sb.st_size);
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if(DETECT_BROKEN) {
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if(virname)
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*virname = "Broken.Executable";
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free(section_hdr);
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return CL_VIRUS;
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}
|
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broken = 1;
|
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}
|
|
|
|
if(!i) {
|
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min = EC32(section_hdr[i].VirtualAddress);
|
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max = EC32(section_hdr[i].VirtualAddress) + EC32(section_hdr[i].SizeOfRawData);
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} else {
|
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if(EC32(section_hdr[i].VirtualAddress) < min)
|
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min = EC32(section_hdr[i].VirtualAddress);
|
|
|
|
if(EC32(section_hdr[i].VirtualAddress) + EC32(section_hdr[i].SizeOfRawData) > max)
|
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max = EC32(section_hdr[i].VirtualAddress) + EC32(section_hdr[i].SizeOfRawData);
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}
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|
|
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}
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|
|
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if((ep = EC32(optional_hdr.AddressOfEntryPoint)) >= min && !(ep = cli_rawaddr(EC32(optional_hdr.AddressOfEntryPoint), section_hdr, nsections, &err)) && err) {
|
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cli_dbgmsg("Possibly broken PE file\n");
|
|
free(section_hdr);
|
|
if(DETECT_BROKEN) {
|
|
if(virname)
|
|
*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(!dll && ep == EC32(section_hdr[nsections - 1].PointerToRawData)) {
|
|
lseek(desc, ep, SEEK_SET);
|
|
if(read(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) {
|
|
*virname = "W32.Parite.B";
|
|
free(section_hdr);
|
|
return CL_VIRUS;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* W32.Magistr.A/B */
|
|
if(!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(read(desc, buff, 4096) == 4096) {
|
|
if(cli_memstr(buff, 4091, "\xe8\x2c\x61\x00\x00", 5)) {
|
|
*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(read(desc, buff, 4096) == 4096) {
|
|
if(cli_memstr(buff, 4091, "\xe8\x04\x72\x00\x00", 5)) {
|
|
*virname = "W32.Magistr.B";
|
|
free(section_hdr);
|
|
return CL_VIRUS;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if(broken) {
|
|
free(section_hdr);
|
|
return CL_CLEAN;
|
|
}
|
|
|
|
/* 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(read(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(limits && limits->maxfilesize && (ssize > limits->maxfilesize || dsize > limits->maxfilesize)) {
|
|
cli_dbgmsg("FSG: Sizes exceeded (ssize: %d, dsize: %d, max: %lu)\n", ssize, dsize , limits->maxfilesize);
|
|
free(section_hdr);
|
|
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_hdr.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) read(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_hdr.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_hdr.ImageBase);
|
|
newesi = cli_readint32(dest + 4) - EC32(optional_hdr.ImageBase);
|
|
newebx = cli_readint32(dest + 16) - EC32(optional_hdr.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;
|
|
}
|
|
|
|
/* FIXME: unused atm, needed for pe rebuilding */
|
|
cli_dbgmsg("FSG: found old EP @%x\n", cli_readint32(newebx + 12 - EC32(section_hdr[i + 1].VirtualAddress) + src) - EC32(optional_hdr.ImageBase));
|
|
|
|
if((dest = (char *) cli_calloc(dsize, sizeof(char))) == NULL) {
|
|
free(section_hdr);
|
|
free(src);
|
|
return CL_EMEM;
|
|
}
|
|
|
|
if(unfsg_200(newesi - EC32(section_hdr[i + 1].VirtualAddress) + src, dest, ssize + EC32(section_hdr[i + 1].VirtualAddress) - newesi, dsize) == -1) {
|
|
cli_dbgmsg("FSG: Unpacking failed\n");
|
|
free(src);
|
|
free(dest);
|
|
break;
|
|
}
|
|
|
|
found = 0;
|
|
upx_success = 1;
|
|
cli_dbgmsg("FSG: Successfully decompressed\n");
|
|
}
|
|
}
|
|
|
|
if(found && buff[0] == '\xbe' && cli_readint32(buff + 1) - EC32(optional_hdr.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(limits && limits->maxfilesize && (ssize > limits->maxfilesize || dsize > limits->maxfilesize)) {
|
|
cli_dbgmsg("FSG: Sizes exceeded (ssize: %d, dsize: %d, max: %lu)\n", ssize, dsize, limits->maxfilesize);
|
|
free(section_hdr);
|
|
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_hdr.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(limits && limits->maxfilesize && (unsigned int) gp > limits->maxfilesize) {
|
|
cli_dbgmsg("FSG: Buffer size exceeded (size: %d, max: %lu)\n", gp, limits->maxfilesize);
|
|
free(section_hdr);
|
|
return CL_CLEAN;
|
|
}
|
|
|
|
if((support = (char *) cli_malloc(gp)) == NULL) {
|
|
free(section_hdr);
|
|
return CL_EMEM;
|
|
}
|
|
|
|
if(read(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_hdr.ImageBase); /* Unused */
|
|
newedi = cli_readint32(support + 4) - EC32(optional_hdr.ImageBase); /* 1st dest */
|
|
newesi = cli_readint32(support + 8) - EC32(optional_hdr.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_hdr.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_hdr.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) read(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_hdr.AddressOfEntryPoint) + 161 + 6 + cli_readint32(buff+163);
|
|
cli_dbgmsg("FSG: found old EP @%x\n", oldep);
|
|
|
|
tempfile = cli_gentemp(NULL);
|
|
if((ndesc = open(tempfile, O_RDWR|O_CREAT|O_TRUNC, 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_hdr.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, virname, scanned, root, limits, options, arec, mrec) == 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_hdr.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_hdr.ImageBase), t, sectcnt = 0;
|
|
char *support;
|
|
uint32_t newesi = cli_readint32(buff+11) - EC32(optional_hdr.ImageBase);
|
|
uint32_t newedi = cli_readint32(buff+6) - EC32(optional_hdr.ImageBase);
|
|
uint32_t oldep = EC32(optional_hdr.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(limits && limits->maxfilesize && (ssize > limits->maxfilesize || dsize > limits->maxfilesize)) {
|
|
cli_dbgmsg("FSG: Sizes exceeded (ssize: %d, dsize: %d, max: %lu)\n", ssize, dsize, limits->maxfilesize);
|
|
free(section_hdr);
|
|
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(limits && limits->maxfilesize && (unsigned int) gp > limits->maxfilesize) {
|
|
cli_dbgmsg("FSG: Buffer size exceeded (size: %d, max: %lu)\n", gp, limits->maxfilesize);
|
|
free(section_hdr);
|
|
return CL_CLEAN;
|
|
}
|
|
|
|
if((support = (char *) cli_malloc(gp)) == NULL) {
|
|
free(section_hdr);
|
|
return CL_EMEM;
|
|
}
|
|
|
|
if(read(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_hdr.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_hdr.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) read(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_hdr.AddressOfEntryPoint) + gp + 6 + cli_readint32(src+gp+2+oldep);
|
|
cli_dbgmsg("FSG: found old EP @%x\n", oldep);
|
|
|
|
tempfile = cli_gentemp(NULL);
|
|
if((ndesc = open(tempfile, O_RDWR|O_CREAT|O_TRUNC, 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_hdr.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, virname, scanned, root, limits, options, arec, mrec) == 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, section_hdr[i].Name, 8);
|
|
sname[8] = 0;
|
|
cli_dbgmsg("UPX: Section %d name: %s\n", i, sname);
|
|
strncpy(sname, section_hdr[i + 1].Name, 8);
|
|
sname[8] = 0;
|
|
cli_dbgmsg("UPX: Section %d name: %s\n", i + 1, sname);
|
|
|
|
if(strncmp(section_hdr[i].Name, "UPX0", 4) || strncmp(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(limits && limits->maxfilesize && (ssize > limits->maxfilesize || dsize > limits->maxfilesize)) {
|
|
cli_dbgmsg("UPX: Sizes exceeded (ssize: %d, dsize: %d, max: %lu)\n", ssize, dsize , limits->maxfilesize);
|
|
free(section_hdr);
|
|
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((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) read(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(read(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_hdr.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_hdr.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_hdr.AddressOfEntryPoint)-skew) >= 0 || upxfn(src, ssize, dest, &dsize, EC32(section_hdr[i].VirtualAddress), EC32(section_hdr[i + 1].VirtualAddress), EC32(optional_hdr.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_hdr.AddressOfEntryPoint)) == -1 && upx_inflate2b(src + 0x15, ssize - 0x15, dest, &dsize, EC32(section_hdr[i].VirtualAddress), EC32(section_hdr[i + 1].VirtualAddress), EC32(optional_hdr.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_hdr.AddressOfEntryPoint)) == -1 && upx_inflate2d(src + 0x15, ssize - 0x15, dest, &dsize, EC32(section_hdr[i].VirtualAddress), EC32(section_hdr[i + 1].VirtualAddress), EC32(optional_hdr.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_hdr.AddressOfEntryPoint)) == -1 && upx_inflate2e(src + 0x15, ssize - 0x15, dest, &dsize, EC32(section_hdr[i].VirtualAddress), EC32(section_hdr[i + 1].VirtualAddress), EC32(optional_hdr.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);
|
|
|
|
tempfile = cli_gentemp(NULL);
|
|
if((ndesc = open(tempfile, O_RDWR|O_CREAT|O_TRUNC, 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 rebuilt PE file *****\n");
|
|
if((ret = cli_magic_scandesc(ndesc, virname, scanned, root, limits, options, arec, mrec)) == 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(read(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_hdr.ImageBase)) {
|
|
if(nsections < 2 || buff[0] != '\xb8' || (uint32_t) cli_readint32(buff + 1) != EC32(section_hdr[nsections - 2].VirtualAddress) + EC32(optional_hdr.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(limits && limits->maxfilesize && dsize > limits->maxfilesize) {
|
|
cli_dbgmsg("Petite: Size exceeded (dsize: %d, max: %lu)\n", dsize, limits->maxfilesize);
|
|
free(section_hdr);
|
|
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) read(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;
|
|
}
|
|
}
|
|
}
|
|
|
|
tempfile = cli_gentemp(NULL);
|
|
if((ndesc = open(tempfile, O_RDWR|O_CREAT|O_TRUNC, 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_hdr.ImageBase),
|
|
EC32(optional_hdr.AddressOfEntryPoint), ndesc,
|
|
found, EC32(optional_hdr.DataDirectory[2].VirtualAddress),
|
|
EC32(optional_hdr.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, virname, scanned, root, limits, options, arec, mrec) == 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);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* to be continued ... */
|
|
|
|
free(section_hdr);
|
|
return CL_CLEAN;
|
|
}
|
|
|
|
int cli_peheader(int desc, struct cli_pe_info *peinfo)
|
|
{
|
|
uint16_t e_magic; /* DOS signature ("MZ") */
|
|
uint32_t e_lfanew; /* address of new exe header */
|
|
struct pe_image_file_hdr file_hdr;
|
|
struct pe_image_optional_hdr optional_hdr;
|
|
struct pe_image_section_hdr *section_hdr;
|
|
struct stat sb;
|
|
int i;
|
|
unsigned int err;
|
|
|
|
|
|
cli_dbgmsg("in cli_peheader\n");
|
|
|
|
if(read(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(read(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(read(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;
|
|
}
|
|
|
|
if(EC16(file_hdr.SizeOfOptionalHeader) != sizeof(struct pe_image_optional_hdr)) {
|
|
cli_warnmsg("Broken PE header detected.\n");
|
|
return -1;
|
|
}
|
|
|
|
peinfo->nsections = EC16(file_hdr.NumberOfSections);
|
|
|
|
if(read(desc, &optional_hdr, sizeof(struct pe_image_optional_hdr)) != sizeof(struct pe_image_optional_hdr)) {
|
|
cli_dbgmsg("Can't optional file header\n");
|
|
return -1;
|
|
}
|
|
|
|
peinfo->section = (struct SECTION *) cli_calloc(peinfo->nsections, sizeof(struct 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(read(desc, §ion_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);
|
|
}
|
|
|
|
peinfo->ep = cli_rawaddr(EC32(optional_hdr.AddressOfEntryPoint), section_hdr, peinfo->nsections, &err);
|
|
|
|
if(err) {
|
|
cli_dbgmsg("Possibly broken PE file\n");
|
|
free(section_hdr);
|
|
free(peinfo->section);
|
|
return -1;
|
|
}
|
|
|
|
free(section_hdr);
|
|
return 0;
|
|
}
|
|
|