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/* |
d6bc83e4 |
* Copyright (C) 2004 - 2005 Tomasz Kojm <tkojm@clamav.net> |
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* |
3daea9cf |
* With additions from aCaB <acab@clamav.net>
* |
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* 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., 675 Mass Ave, Cambridge, MA 02139, 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>
#include <unistd.h>
#include <time.h>
#include "cltypes.h"
#include "clamav.h"
#include "others.h" |
5ede41fa |
#include "pe.h" |
f2eb2372 |
#include "upx.h" |
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#include "petite.h" |
3c5b57d4 |
#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 */ |
3d9cb459 |
#define IMAGE_DOS_SIGNATURE_OLD 0x4d5a /* ZM */ |
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#define IMAGE_NT_SIGNATURE 0x00004550
#define IMAGE_OPTIONAL_SIGNATURE 0x010b
|
ac4e01f9 |
#define DETECT_BROKEN (options & CL_SCAN_BLOCKBROKEN) |
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#define BLOCKMAX (options & CL_SCAN_BLOCKMAX) |
f8355d13 |
|
3d9cb459 |
#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" |
f2eb2372 |
|
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#if WORDS_BIGENDIAN == 0
#define EC16(v) (v)
#define EC32(v) (v)
#else
static inline uint16_t EC16(uint16_t v)
{
return ((v >> 8) + (v << 8));
}
static inline uint32_t EC32(uint32_t v)
{
return ((v >> 24) | ((v & 0x00FF0000) >> 8) | ((v & 0x0000FF00) << 8) | (v << 24));
}
#endif
extern short cli_leavetemps_flag;
|
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struct offset_list {
uint32_t offset;
struct offset_list *next;
};
|
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static uint32_t cli_rawaddr(uint32_t rva, struct pe_image_section_hdr *shp, uint16_t nos, unsigned int *err) |
e3886d61 |
{
int i, found = 0;
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) { |
e3886d61 |
found = 1;
break;
}
}
if(!found) { |
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*err = 1;
return 0; |
e3886d61 |
}
|
a8b53539 |
*err = 0; |
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return rva - EC32(shp[i].VirtualAddress) + EC32(shp[i].PointerToRawData); |
e3886d61 |
}
|
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/* |
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static int cli_ddump(int desc, int offset, int size, const char *file) |
cea6b75d |
{
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"); |
c2484690 |
return -1; |
cea6b75d |
}
if(lseek(desc, offset, SEEK_SET) == -1) {
cli_dbgmsg("lseek() failed\n");
lseek(desc, pos, SEEK_SET); |
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return -1; |
cea6b75d |
}
if((ndesc = open(file, O_WRONLY|O_CREAT|O_TRUNC, S_IRWXU)) < 0) {
cli_dbgmsg("Can't create file %s\n", file);
lseek(desc, pos, SEEK_SET); |
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return -1; |
cea6b75d |
}
while((bread = read(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); |
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return -1; |
cea6b75d |
}
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); |
c2484690 |
return -1; |
cea6b75d |
}
}
sum += bread;
}
close(ndesc);
lseek(desc, pos, SEEK_SET);
return 0;
} |
a8b53539 |
*/ |
cea6b75d |
|
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int cli_scanpe(int desc, const char **virname, unsigned 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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{
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 */ |
e3886d61 |
uint32_t ep; /* entry point (raw) */ |
f0635204 |
uint8_t polipos = 0; |
f91f55e0 |
time_t timestamp; |
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struct pe_image_file_hdr file_hdr;
struct pe_image_optional_hdr optional_hdr; |
e3886d61 |
struct pe_image_section_hdr *section_hdr; |
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struct stat sb; |
289ed7c4 |
char sname[9], buff[4096], *tempfile; |
f0635204 |
unsigned char *ubuff;
ssize_t bytes; |
b76bf2c4 |
unsigned int i, found, upx_success = 0, min = 0, max = 0, err, broken = 0;
unsigned int ssize = 0, dsize = 0, dll = 0; |
d99b1840 |
int (*upxfn)(char *, uint32_t , char *, uint32_t *, uint32_t, uint32_t, uint32_t) = NULL; |
0d32af73 |
char *src = NULL, *dest = NULL; |
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int ndesc, ret = CL_CLEAN; |
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if(read(desc, &e_magic, sizeof(e_magic)) != sizeof(e_magic)) { |
cea6b75d |
cli_dbgmsg("Can't read DOS signature\n"); |
1f576bce |
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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}
lseek(desc, 58, SEEK_CUR); /* skip to the end of the DOS header */
if(read(desc, &e_lfanew, sizeof(e_lfanew)) != sizeof(e_lfanew)) { |
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cli_dbgmsg("Can't read new header address\n"); |
1f576bce |
/* truncated header? */
if(DETECT_BROKEN) {
if(virname)
*virname = "Broken.Executable";
return CL_VIRUS;
}
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);
if(!e_lfanew) {
cli_dbgmsg("Not a PE file\n"); |
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return CL_CLEAN; |
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} |
0b2b8b9b |
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;
} |
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if(read(desc, &file_hdr, sizeof(struct pe_image_file_hdr)) != sizeof(struct pe_image_file_hdr)) { |
0b2b8b9b |
/* bad information in e_lfanew - probably not a PE file */ |
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cli_dbgmsg("Can't read file header\n"); |
0b2b8b9b |
return CL_CLEAN; |
e60810eb |
}
|
c2484690 |
if(EC32(file_hdr.Magic) != IMAGE_NT_SIGNATURE) { |
cea6b75d |
cli_dbgmsg("Invalid PE signature (probably NE file)\n"); |
c2484690 |
return CL_CLEAN; |
e60810eb |
}
|
b76bf2c4 |
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");
}
|
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switch(EC16(file_hdr.Machine)) { |
9c8806fb |
case 0x0:
cli_dbgmsg("Machine type: Unknown\n"); |
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case 0x14c: |
cea6b75d |
cli_dbgmsg("Machine type: 80386\n"); |
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break; |
9c8806fb |
case 0x14d: |
cea6b75d |
cli_dbgmsg("Machine type: 80486\n"); |
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break; |
9c8806fb |
case 0x14e: |
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cli_dbgmsg("Machine type: 80586\n"); |
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break; |
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case 0x160:
cli_dbgmsg("Machine type: R30000 (big-endian)\n");
break; |
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case 0x162: |
cea6b75d |
cli_dbgmsg("Machine type: R3000\n"); |
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break;
case 0x166: |
cea6b75d |
cli_dbgmsg("Machine type: R4000\n"); |
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break;
case 0x168: |
cea6b75d |
cli_dbgmsg("Machine type: R10000\n"); |
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break;
case 0x184: |
cea6b75d |
cli_dbgmsg("Machine type: DEC Alpha AXP\n"); |
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break; |
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case 0x284:
cli_dbgmsg("Machine type: DEC Alpha AXP 64bit\n");
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:
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; |
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case 0x1a3:
cli_dbgmsg("Machine type: Hitachi SH3-DSP\n");
break;
case 0x1a4:
cli_dbgmsg("Machine type: Hitachi SH3-E\n");
break; |
da034cc1 |
case 0x1a6:
cli_dbgmsg("Machine type: Hitachi SH4\n");
break; |
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case 0x1a8:
cli_dbgmsg("Machine type: Hitachi SH5\n");
break; |
da034cc1 |
case 0x1c0:
cli_dbgmsg("Machine type: ARM\n");
break;
case 0x1c2:
cli_dbgmsg("Machine type: THUMB\n");
break; |
9c8806fb |
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; |
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default: |
da034cc1 |
cli_warnmsg("Unknown machine type in PE header (0x%x)\n", EC16(file_hdr.Machine)); |
e60810eb |
}
|
c2484690 |
nsections = EC16(file_hdr.NumberOfSections); |
e82a5185 |
if(nsections < 1 || nsections > 99) { |
f2284195 |
if(DETECT_BROKEN) {
if(virname)
*virname = "Broken.Executable";
return CL_VIRUS;
} |
e82a5185 |
if(nsections)
cli_warnmsg("PE file contains %d sections\n", nsections);
else
cli_warnmsg("PE file contains no sections\n"); |
f2284195 |
return CL_CLEAN;
} |
c2484690 |
cli_dbgmsg("NumberOfSections: %d\n", nsections);
|
f91f55e0 |
timestamp = (time_t) EC32(file_hdr.TimeDateStamp);
cli_dbgmsg("TimeDateStamp: %s", ctime(×tamp)); |
e60810eb |
|
c2484690 |
cli_dbgmsg("SizeOfOptionalHeader: %d\n", EC16(file_hdr.SizeOfOptionalHeader)); |
e60810eb |
|
c2484690 |
if(EC16(file_hdr.SizeOfOptionalHeader) != sizeof(struct pe_image_optional_hdr)) { |
d99b1840 |
/* Support for PE32+ binaries available in CVS */ |
c2484690 |
return CL_CLEAN; |
e60810eb |
}
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"); |
f8355d13 |
if(DETECT_BROKEN) {
if(virname)
*virname = "Broken.Executable";
return CL_VIRUS;
}
return CL_CLEAN; |
e60810eb |
}
cli_dbgmsg("MajorLinkerVersion: %d\n", optional_hdr.MajorLinkerVersion);
cli_dbgmsg("MinorLinkerVersion: %d\n", optional_hdr.MinorLinkerVersion); |
c2484690 |
cli_dbgmsg("SizeOfCode: %d\n", EC32(optional_hdr.SizeOfCode));
cli_dbgmsg("SizeOfInitializedData: %d\n", EC32(optional_hdr.SizeOfInitializedData));
cli_dbgmsg("SizeOfUninitializedData: %d\n", EC32(optional_hdr.SizeOfUninitializedData));
cli_dbgmsg("AddressOfEntryPoint: 0x%x\n", EC32(optional_hdr.AddressOfEntryPoint));
cli_dbgmsg("SectionAlignment: %d\n", EC32(optional_hdr.SectionAlignment));
cli_dbgmsg("FileAlignment: %d\n", EC32(optional_hdr.FileAlignment));
cli_dbgmsg("MajorSubsystemVersion: %d\n", EC16(optional_hdr.MajorSubsystemVersion));
cli_dbgmsg("MinorSubsystemVersion: %d\n", EC16(optional_hdr.MinorSubsystemVersion));
cli_dbgmsg("SizeOfImage: %d\n", EC32(optional_hdr.SizeOfImage));
cli_dbgmsg("SizeOfHeaders: %d\n", EC32(optional_hdr.SizeOfHeaders));
switch(EC16(optional_hdr.Subsystem)) { |
04268c03 |
case 0:
cli_dbgmsg("Subsystem: Unknown\n");
break; |
e60810eb |
case 1: |
cea6b75d |
cli_dbgmsg("Subsystem: Native (a driver ?)\n"); |
e60810eb |
break;
case 2: |
cea6b75d |
cli_dbgmsg("Subsystem: Win32 GUI\n"); |
e60810eb |
break;
case 3: |
cea6b75d |
cli_dbgmsg("Subsystem: Win32 console\n"); |
e60810eb |
break;
case 5: |
cea6b75d |
cli_dbgmsg("Subsystem: OS/2 console\n"); |
e60810eb |
break;
case 7: |
cea6b75d |
cli_dbgmsg("Subsystem: POSIX console\n"); |
e60810eb |
break; |
da034cc1 |
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; |
e60810eb |
default: |
04268c03 |
cli_warnmsg("Unknown subsystem in PE header (0x%x)\n", EC16(optional_hdr.Subsystem)); |
e60810eb |
}
|
c2484690 |
cli_dbgmsg("NumberOfRvaAndSizes: %d\n", EC32(optional_hdr.NumberOfRvaAndSizes)); |
5ede41fa |
cli_dbgmsg("------------------------------------\n"); |
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|
e263999b |
if(fstat(desc, &sb) == -1) {
cli_dbgmsg("fstat failed\n");
return CL_EIO;
}
|
c2484690 |
section_hdr = (struct pe_image_section_hdr *) cli_calloc(nsections, sizeof(struct pe_image_section_hdr)); |
e3886d61 |
if(!section_hdr) {
cli_dbgmsg("Can't allocate memory for section headers\n");
return CL_EMEM;
}
|
c2484690 |
for(i = 0; i < nsections; i++) { |
e60810eb |
|
e3886d61 |
if(read(desc, §ion_hdr[i], sizeof(struct pe_image_section_hdr)) != sizeof(struct pe_image_section_hdr)) { |
e60810eb |
cli_dbgmsg("Can't read section header\n"); |
55ab2cea |
cli_dbgmsg("Possibly broken PE file\n"); |
e3886d61 |
free(section_hdr); |
f8355d13 |
if(DETECT_BROKEN) {
if(virname)
*virname = "Broken.Executable";
return CL_VIRUS;
} |
f2eb2372 |
return CL_CLEAN; |
e60810eb |
}
|
e3886d61 |
strncpy(sname, section_hdr[i].Name, 8); |
e60810eb |
sname[8] = 0; |
8ce7d5f5 |
cli_dbgmsg("Section %d\n", i); |
e60810eb |
cli_dbgmsg("Section name: %s\n", sname); |
c2484690 |
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)); |
e60810eb |
|
c2484690 |
if(EC32(section_hdr[i].Characteristics) & 0x20) { |
cea6b75d |
cli_dbgmsg("Section contains executable code\n");
|
c2484690 |
if(EC32(section_hdr[i].VirtualSize) < EC32(section_hdr[i].SizeOfRawData)) { |
cea6b75d |
cli_dbgmsg("Section contains free space\n");
/*
cli_dbgmsg("Dumping %d bytes\n", section_hdr.SizeOfRawData - section_hdr.VirtualSize); |
f91f55e0 |
ddump(desc, section_hdr.PointerToRawData + section_hdr.VirtualSize, section_hdr.SizeOfRawData - section_hdr.VirtualSize, cli_gentemp(NULL)); |
cea6b75d |
*/
}
} |
e60810eb |
|
c2484690 |
if(EC32(section_hdr[i].Characteristics) & 0x20000000) |
cea6b75d |
cli_dbgmsg("Section's memory is executable\n"); |
b76bf2c4 |
if(EC32(section_hdr[i].Characteristics) & 0x80000000)
cli_dbgmsg("Section's memory is writeable\n");
|
5ede41fa |
cli_dbgmsg("------------------------------------\n"); |
cea6b75d |
|
a8b53539 |
if(EC32(section_hdr[i].PointerToRawData) + EC32(section_hdr[i].SizeOfRawData) > (unsigned long int) sb.st_size) { |
f8355d13 |
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);
if(DETECT_BROKEN) {
if(virname)
*virname = "Broken.Executable"; |
b76bf2c4 |
free(section_hdr); |
f8355d13 |
return CL_VIRUS;
} |
b76bf2c4 |
broken = 1; |
f8355d13 |
}
|
5ede41fa |
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); |
cea6b75d |
|
5ede41fa |
if(EC32(section_hdr[i].VirtualAddress) + EC32(section_hdr[i].SizeOfRawData) > max)
max = EC32(section_hdr[i].VirtualAddress) + EC32(section_hdr[i].SizeOfRawData); |
cea6b75d |
} |
e60810eb |
|
f0635204 |
if(!strlen(sname)) {
if(EC32(section_hdr[i].VirtualSize) > 40000 && EC32(section_hdr[i].VirtualSize) < 70000) {
if(EC32(section_hdr[i].Characteristics) == 0xe0000060)
polipos = i;
}
} |
e60810eb |
}
|
a8b53539 |
if((ep = EC32(optional_hdr.AddressOfEntryPoint)) >= min && !(ep = cli_rawaddr(EC32(optional_hdr.AddressOfEntryPoint), section_hdr, nsections, &err)) && err) { |
5ede41fa |
cli_dbgmsg("Possibly broken PE file\n"); |
e3886d61 |
free(section_hdr); |
f8355d13 |
if(DETECT_BROKEN) {
if(virname)
*virname = "Broken.Executable";
return CL_VIRUS;
} |
f2eb2372 |
return CL_CLEAN; |
e60810eb |
}
|
f2eb2372 |
cli_dbgmsg("EntryPoint offset: 0x%x (%d)\n", ep, ep);
|
d6bc83e4 |
/* Attempt to detect some popular polymorphic viruses */
/* W32.Parite.B */ |
b76bf2c4 |
if(!dll && ep == EC32(section_hdr[nsections - 1].PointerToRawData)) { |
3d4cb247 |
lseek(desc, ep, SEEK_SET); |
d6bc83e4 |
if(read(desc, buff, 4096) == 4096) { |
f58ad3be |
const char *pt = cli_memstr(buff, 4040, "\x47\x65\x74\x50\x72\x6f\x63\x41\x64\x64\x72\x65\x73\x73\x00", 15); |
d6bc83e4 |
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"; |
98454000 |
free(section_hdr); |
d6bc83e4 |
return CL_VIRUS;
}
}
}
}
|
b76bf2c4 |
/* 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;
}
}
}
}
|
f0635204 |
/* W32.Polipos.A */
if(polipos && !dll && nsections > 2 && nsections < 13 && e_lfanew <= 0x800 && (EC16(optional_hdr.Subsystem) == 2 || EC16(optional_hdr.Subsystem) == 3) && EC16(file_hdr.Machine) == 0x14c && optional_hdr.SizeOfStackReserve >= 0x80000) {
uint32_t remaining = EC32(section_hdr[0].SizeOfRawData);
uint32_t chunk = sizeof(buff);
uint32_t val, shift, raddr, curroff, 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;
*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;
}
}
|
9c8806fb |
if(broken) {
free(section_hdr); |
b76bf2c4 |
return CL_CLEAN; |
9c8806fb |
} |
b76bf2c4 |
|
3c5b57d4 |
/* UPX & FSG support */ |
c2484690 |
/* try to find the first section with physical size == 0 */
found = 0; |
a8b53539 |
for(i = 0; i < (unsigned int) nsections - 1; i++) { |
3c5b57d4 |
if(!section_hdr[i].SizeOfRawData && section_hdr[i].VirtualSize && section_hdr[i + 1].SizeOfRawData && section_hdr[i + 1].VirtualSize) { |
c2484690 |
found = 1; |
3c5b57d4 |
cli_dbgmsg("UPX/FSG: empty section found - assuming compression\n"); |
c2484690 |
break;
}
}
if(found) {
|
3c5b57d4 |
/* Check EP for UPX vs. FSG */
if(lseek(desc, ep, SEEK_SET) == -1) {
cli_dbgmsg("UPX/FSG: lseek() failed\n"); |
9c3920b9 |
free(section_hdr); |
3c5b57d4 |
return CL_EIO; |
5115a5eb |
}
|
3daea9cf |
if(read(desc, buff, 168) != 168) { |
6bd80fe3 |
cli_dbgmsg("UPX/FSG: Can't read 168 bytes at 0x%x (%d)\n", ep, ep); |
b5666f50 |
cli_dbgmsg("UPX/FSG: Broken or not UPX/FSG compressed file\n"); |
3c5b57d4 |
free(section_hdr); |
b5666f50 |
return CL_CLEAN; |
fbbf7cd2 |
}
|
3daea9cf |
if(buff[0] == '\x87' && buff[1] == '\x25') { |
f2eb2372 |
|
3daea9cf |
/* FSG v2.0 support - thanks to aCaB ! */ |
f2eb2372 |
|
3c5b57d4 |
ssize = EC32(section_hdr[i + 1].SizeOfRawData);
dsize = EC32(section_hdr[i].VirtualSize); |
f2eb2372 |
|
3c5b57d4 |
while(found) {
uint32_t newesi, newedi, newebx, newedx; |
5115a5eb |
|
3c5b57d4 |
if(limits && limits->maxfilesize && (ssize > limits->maxfilesize || dsize > limits->maxfilesize)) { |
e82a5185 |
cli_dbgmsg("FSG: Sizes exceeded (ssize: %u, dsize: %u, max: %lu)\n", ssize, dsize , limits->maxfilesize); |
3c5b57d4 |
free(section_hdr); |
d99b1840 |
if(BLOCKMAX) {
*virname = "PE.FSG.ExceededFileSize";
return CL_VIRUS;
} else {
return CL_CLEAN;
} |
3c5b57d4 |
} |
5115a5eb |
|
3c5b57d4 |
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); |
a8b53539 |
if((unsigned int) read(desc, src, ssize) != ssize) { |
3c5b57d4 |
cli_dbgmsg("Can't read raw data of section %d\n", i);
free(section_hdr);
free(src);
return CL_EIO;
}
|
a8b53539 |
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)) { |
3c5b57d4 |
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;
}
|
d99b1840 |
newedx=cli_readint32(newebx + 12 - EC32(section_hdr[i + 1].VirtualAddress) + src) - EC32(optional_hdr.ImageBase);
cli_dbgmsg("FSG: found old EP @%x\n",newedx); |
3c5b57d4 |
if((dest = (char *) cli_calloc(dsize, sizeof(char))) == NULL) {
free(section_hdr);
free(src);
return CL_EMEM;
}
|
d99b1840 |
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);
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_hdr.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, 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: Successfully decompressed\n");
close(ndesc);
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);
free(tempfile);
free(src);
free(dest);
break; |
3c5b57d4 |
}
|
d99b1840 |
break; /* were done with 2 */ |
5115a5eb |
}
}
|
3daea9cf |
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) { |
6bd80fe3 |
int gp, t, sectcnt = 0; |
3daea9cf |
char *support;
uint32_t newesi, newedi, newebx, oldep;
struct SECTION *sections;
if(limits && limits->maxfilesize && (ssize > limits->maxfilesize || dsize > limits->maxfilesize)) { |
e82a5185 |
cli_dbgmsg("FSG: Sizes exceeded (ssize: %u, dsize: %u, max: %lu)\n", ssize, dsize, limits->maxfilesize); |
3daea9cf |
free(section_hdr); |
d99b1840 |
if(BLOCKMAX) {
*virname = "PE.FSG.ExceededFileSize";
return CL_VIRUS;
} else {
return CL_CLEAN;
} |
3daea9cf |
}
if(ssize <= 0x19 || dsize <= ssize) {
cli_dbgmsg("FSG: Size mismatch (ssize: %d, dsize: %d)\n", ssize, dsize);
free(section_hdr);
return CL_CLEAN;
}
|
a8b53539 |
if((gp = cli_readint32(buff + 1) - EC32(optional_hdr.ImageBase)) >= (int) EC32(section_hdr[i + 1].PointerToRawData) || gp < 0) { |
0d32af73 |
cli_dbgmsg("FSG: Support data out of padding area (vaddr: %d)\n", EC32(section_hdr[i].VirtualAddress)); |
3daea9cf |
break;
}
|
6bd80fe3 |
lseek(desc, gp, SEEK_SET);
gp = EC32(section_hdr[i + 1].PointerToRawData) - gp;
|
a8b53539 |
if(limits && limits->maxfilesize && (unsigned int) gp > limits->maxfilesize) { |
3daea9cf |
cli_dbgmsg("FSG: Buffer size exceeded (size: %d, max: %lu)\n", gp, limits->maxfilesize);
free(section_hdr); |
d99b1840 |
if(BLOCKMAX) {
*virname = "PE.FSG.ExceededFileSize";
return CL_VIRUS;
} else {
return CL_CLEAN;
} |
3daea9cf |
}
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 */
|
9c8806fb |
if(newesi < EC32(section_hdr[i + 1].VirtualAddress) || newesi >= EC32(section_hdr[i + 1].VirtualAddress) + EC32(section_hdr[i + 1].SizeOfRawData)) { |
3daea9cf |
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;
}
}
|
d8f0a45c |
if(t >= gp - 4 || cli_readint32(support + t)) { |
3daea9cf |
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); |
a8b53539 |
if((unsigned int) read(desc, src, ssize) != ssize) { |
3daea9cf |
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);
|
7c00689d |
cli_dbgmsg("***** Scanning rebuilt PE file *****\n"); |
3daea9cf |
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 */
}
}
|
6bd80fe3 |
/* 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);
|
9c8806fb |
if(newesi < EC32(section_hdr[i + 1].VirtualAddress) || newesi >= EC32(section_hdr[i + 1].VirtualAddress) + EC32(section_hdr[i + 1].SizeOfRawData)) { |
6bd80fe3 |
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)) { |
e82a5185 |
cli_dbgmsg("FSG: Sizes exceeded (ssize: %u, dsize: %u, max: %lu)\n", ssize, dsize, limits->maxfilesize); |
6bd80fe3 |
free(section_hdr); |
d99b1840 |
if(BLOCKMAX) {
*virname = "PE.FSG.ExceededFileSize";
return CL_VIRUS;
} else {
return CL_CLEAN;
} |
6bd80fe3 |
}
if(ssize <= 0x19 || dsize <= ssize) {
cli_dbgmsg("FSG: Size mismatch (ssize: %d, dsize: %d)\n", ssize, dsize);
free(section_hdr);
return CL_CLEAN;
}
|
a8b53539 |
if(gp >= (int) EC32(section_hdr[i + 1].PointerToRawData) || gp < 0) { |
6bd80fe3 |
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;
|
a8b53539 |
if(limits && limits->maxfilesize && (unsigned int) gp > limits->maxfilesize) { |
6bd80fe3 |
cli_dbgmsg("FSG: Buffer size exceeded (size: %d, max: %lu)\n", gp, limits->maxfilesize);
free(section_hdr); |
d99b1840 |
if(BLOCKMAX) {
*virname = "PE.FSG.ExceededFileSize";
return CL_VIRUS;
} else {
return CL_CLEAN;
} |
6bd80fe3 |
}
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;
}
}
|
d6bc83e4 |
if(t >= gp-10 || cli_readint32(support + t + 6) != 2) { |
6bd80fe3 |
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); |
a8b53539 |
if((unsigned int) read(desc, src, ssize) != ssize) { |
6bd80fe3 |
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 */ |
920406d9 |
gp = 0xda + 6*(buff[16]=='\xe8');
oldep = EC32(optional_hdr.AddressOfEntryPoint) + gp + 6 + cli_readint32(src+gp+2+oldep); |
6bd80fe3 |
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);
|
7c00689d |
cli_dbgmsg("***** Scanning rebuilt PE file *****\n"); |
6bd80fe3 |
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; |
d99b1840 |
break; /* Go and scan the decompressed data */ |
6bd80fe3 |
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 */
}
}
|
3c5b57d4 |
if(found) { |
fbbf7cd2 |
|
3c5b57d4 |
/* UPX support */ |
fbbf7cd2 |
|
3c5b57d4 |
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)) { |
e82a5185 |
cli_dbgmsg("UPX: Sizes exceeded (ssize: %u, dsize: %u, max: %lu)\n", ssize, dsize , limits->maxfilesize); |
3c5b57d4 |
free(section_hdr); |
d99b1840 |
if(BLOCKMAX) {
*virname = "PE.UPX.ExceededFileSize";
return CL_VIRUS;
} else {
return CL_CLEAN;
} |
f2eb2372 |
} |
fbbf7cd2 |
|
3c5b57d4 |
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;
} |
f2eb2372 |
|
3c5b57d4 |
/* FIXME: use file operations in case of big files */
if((src = (char *) cli_malloc(ssize)) == NULL) {
free(section_hdr);
return CL_EMEM; |
f2eb2372 |
}
|
e82a5185 |
if(dsize > CLI_MAX_ALLOCATION) {
cli_errmsg("UPX: Too big value of dsize\n");
free(section_hdr);
free(src);
return CL_EMEM;
}
|
7c00689d |
if((dest = (char *) cli_calloc(dsize + 1024 + nsections * 40, sizeof(char))) == NULL) { |
3c5b57d4 |
free(section_hdr);
free(src);
return CL_EMEM; |
f2eb2372 |
}
|
3c5b57d4 |
lseek(desc, EC32(section_hdr[i + 1].PointerToRawData), SEEK_SET); |
a8b53539 |
if((unsigned int) read(desc, src, ssize) != ssize) { |
3c5b57d4 |
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); |
b5666f50 |
cli_dbgmsg("UPX/FSG: Broken or not UPX/FSG compressed file\n"); |
3c5b57d4 |
free(section_hdr);
free(src);
free(dest); |
b5666f50 |
return CL_CLEAN; |
f2eb2372 |
} else { |
3c5b57d4 |
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);
|
d6bc83e4 |
if(buff[1] != '\xbe' || skew <= 0 || skew > 0xfff) { /* FIXME: legit skews?? */ |
3c5b57d4 |
skew = 0; |
7c00689d |
if(upxfn(src, ssize, dest, &dsize, EC32(section_hdr[i].VirtualAddress), EC32(section_hdr[i + 1].VirtualAddress), EC32(optional_hdr.AddressOfEntryPoint)) >= 0) |
3c5b57d4 |
upx_success = 1;
} else {
cli_dbgmsg("UPX: UPX1 seems skewed by %d bytes\n", skew); |
7c00689d |
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) |
3c5b57d4 |
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) { |
7c00689d |
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) {
|
3c5b57d4 |
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) { |
7c00689d |
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) {
|
3c5b57d4 |
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) { |
7c00689d |
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) { |
3c5b57d4 |
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); |
c2484690 |
}
} |
f2eb2372 |
|
3c5b57d4 |
if(upx_success) { |
7c00689d |
free(src);
free(section_hdr); |
f2eb2372 |
|
7c00689d |
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;
} |
f2eb2372 |
|
a8b53539 |
if((unsigned int) write(ndesc, dest, dsize) != dsize) { |
7c00689d |
cli_dbgmsg("UPX/FSG: Can't write %d bytes\n", dsize);
free(tempfile);
free(dest); |
f2eb2372 |
close(ndesc); |
7c00689d |
return CL_EIO;
}
free(dest);
fsync(ndesc);
lseek(ndesc, 0, SEEK_SET);
if(cli_leavetemps_flag) |
3c5b57d4 |
cli_dbgmsg("UPX/FSG: Decompressed data saved in %s\n", tempfile); |
7c00689d |
|
c840fa41 |
cli_dbgmsg("***** Scanning decompressed data *****\n"); |
7c00689d |
if((ret = cli_magic_scandesc(ndesc, virname, scanned, root, limits, options, arec, mrec)) == CL_VIRUS) {
close(ndesc);
if(!cli_leavetemps_flag)
unlink(tempfile); |
f2eb2372 |
free(tempfile); |
7c00689d |
return CL_VIRUS; |
f2eb2372 |
}
|
7c00689d |
close(ndesc);
if(!cli_leavetemps_flag)
unlink(tempfile);
free(tempfile); |
65ab8d96 |
return ret; |
3c5b57d4 |
} |
f2eb2372 |
} |
e3886d61 |
|
5ede41fa |
/* Petite */
found = 2;
lseek(desc, ep, SEEK_SET); |
f8355d13 |
if(read(desc, buff, 200) != 200) { |
3daea9cf |
cli_dbgmsg("Can't read 200 bytes\n"); |
f8355d13 |
free(section_hdr); |
5ede41fa |
return CL_EIO; |
f8355d13 |
} |
5ede41fa |
|
a8b53539 |
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)) |
5ede41fa |
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) { |
e82a5185 |
cli_dbgmsg("Petite: Size exceeded (dsize: %u, max: %lu)\n", dsize, limits->maxfilesize); |
5ede41fa |
free(section_hdr); |
d99b1840 |
if(BLOCKMAX) {
*virname = "PE.Petite.ExceededFileSize";
return CL_VIRUS;
} else {
return CL_CLEAN;
} |
5ede41fa |
}
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++) { |
65ab8d96 |
if(section_hdr[i].SizeOfRawData) { |
a8b53539 |
uint32_t offset = cli_rawaddr(EC32(section_hdr[i].VirtualAddress), section_hdr, nsections, &err); |
65ab8d96 |
|
a8b53539 |
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)) { |
65ab8d96 |
free(section_hdr);
free(dest);
return CL_EIO;
}
} |
5ede41fa |
}
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;
}
|
65ab8d96 |
/* aCaB: Fixed to allow petite v2.1 unpacking (last section is a ghost) */ |
5ede41fa |
switch(petite_inflate2x_1to9(dest, min, max - min, section_hdr, |
65ab8d96 |
nsections - (found == 1 ? 1 : 0), EC32(optional_hdr.ImageBase), |
d414d959 |
EC32(optional_hdr.AddressOfEntryPoint), ndesc, |
5ede41fa |
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); |
7c00689d |
cli_dbgmsg("***** Scanning rebuilt PE file *****\n"); |
5ede41fa |
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);
}
}
}
|
e60810eb |
/* to be continued ... */
|
e3886d61 |
free(section_hdr); |
f2eb2372 |
return CL_CLEAN; |
e60810eb |
} |
e263999b |
|
856d9c84 |
int cli_peheader(int desc, struct cli_pe_info *peinfo) |
e263999b |
{
uint16_t e_magic; /* DOS signature ("MZ") */
uint32_t e_lfanew; /* address of new exe header */ |
c840fa41 |
uint32_t min, max; |
e263999b |
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; |
a8b53539 |
unsigned int err; |
e263999b |
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)) {
return -1;
}
|
856d9c84 |
peinfo->nsections = EC16(file_hdr.NumberOfSections); |
e263999b |
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;
}
|
856d9c84 |
peinfo->section = (struct SECTION *) cli_calloc(peinfo->nsections, sizeof(struct SECTION)); |
e263999b |
|
856d9c84 |
if(!peinfo->section) { |
e263999b |
cli_dbgmsg("Can't allocate memory for section headers\n");
return -1;
}
if(fstat(desc, &sb) == -1) {
cli_dbgmsg("fstat failed\n"); |
856d9c84 |
free(peinfo->section); |
e263999b |
return -1;
}
|
856d9c84 |
section_hdr = (struct pe_image_section_hdr *) cli_calloc(peinfo->nsections, sizeof(struct pe_image_section_hdr)); |
e263999b |
if(!section_hdr) {
cli_dbgmsg("Can't allocate memory for section headers\n"); |
856d9c84 |
free(peinfo->section); |
e263999b |
return -1;
}
|
856d9c84 |
for(i = 0; i < peinfo->nsections; i++) { |
e263999b |
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); |
856d9c84 |
free(peinfo->section); |
e263999b |
return -1;
}
|
856d9c84 |
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); |
e263999b |
|
c840fa41 |
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);
}
} |
a8b53539 |
|
c840fa41 |
if((peinfo->ep = EC32(optional_hdr.AddressOfEntryPoint)) >= min && !(peinfo->ep = cli_rawaddr(EC32(optional_hdr.AddressOfEntryPoint), section_hdr, peinfo->nsections, &err)) && err) { |
e263999b |
cli_dbgmsg("Possibly broken PE file\n");
free(section_hdr); |
856d9c84 |
free(peinfo->section); |
e263999b |
return -1;
}
free(section_hdr);
return 0;
} |