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#include <sys/types.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <sys/user.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
void
hexdump (unsigned char *data, unsigned int amount);
int
main (int argc, char *argv[])
{
pid_t fpid;
struct user regs;
unsigned long int addr,
len;
unsigned long int addr_walker,
eip;
unsigned char data_saved[256];
if (argc < 5 || sscanf (argv[1], "0x%lx", &eip) != 1 ||
sscanf (argv[2], "0x%lx", &addr) != 1 ||
sscanf (argv[3], "0x%lx", &len) != 1)
{
printf ("usage: %s <eip> <addr> <len> <argv0 [argv1 [...]]>\n\n", argv[0]);
printf ("will run 'argv0' as program with given arguments, until 'eip' is reached, then\n"
"dumping 'len' bytes from 'addr'.\n\n"
"example: %s 0x08049014 0x08048000 0x100 /bin/ls -l\n\n", argv[0]);
exit (EXIT_FAILURE);
}
fpid = fork ();
if (fpid < 0) {
perror ("fork");
exit (EXIT_FAILURE);
}
if (fpid == 0) { /* child */
if (ptrace (PTRACE_TRACEME, 0, NULL, NULL) != 0) {
perror ("ptrace PTRACE_TRACEME");
exit (EXIT_FAILURE);
}
fprintf (stderr, " child: TRACEME set\n");
fprintf (stderr, " child: executing: %s\n", argv[4]);
close (1);
dup2 (2, 1);
execve (argv[4], &argv[4], NULL);
/* failed ? */
perror ("execve");
exit (EXIT_FAILURE);
}
#if 0
if (ptrace (PTRACE_ATTACH, fpid, NULL, NULL) < 0) {
perror ("ptrace");
exit (EXIT_FAILURE);
}
fprintf (stderr, "attached to pid %d (from us, the parent, pid %d)\n", fpid, getpid ());
#endif
// sleep (1);
#if 0
/* trace until trap'ed */
if (ptrace (PTRACE_CONT, fpid, NULL, NULL) < 0) {
perror ("ptrace PTRACE_CONT");
exit (EXIT_FAILURE);
}
#endif
fprintf (stderr, "it should execve now\n");
sleep (1);
memset (®s, 0, sizeof (regs));
if (ptrace (PTRACE_GETREGS, fpid, NULL, ®s) < 0) {
perror ("ptrace PTRACE_GETREGS");
exit (EXIT_FAILURE);
}
fprintf (stderr, "[0x%08lx] first stop\n", regs.regs.eip);
/* now single step until given eip is reached */
do {
if (ptrace (PTRACE_SINGLESTEP, fpid, NULL, NULL) < 0) {
perror ("ptrace PTRACE_SINGLESTEP");
exit (EXIT_FAILURE);
}
wait (NULL);
memset (®s, 0, sizeof (regs));
if (ptrace (PTRACE_GETREGS, fpid, NULL, ®s) < 0) {
perror ("ptrace PTRACE_GETREGS");
exit (EXIT_FAILURE);
}
} while (regs.regs.eip != eip);
fprintf (stderr, "hook traped @ 0x%08lx\n", eip);
fprintf (stderr, "dumping 0x%lx bytes @ 0x%08lx\n", len, addr);
/* save data */
for (addr_walker = 0 ; addr_walker < len ; ++addr_walker) {
errno = 0;
*((unsigned long int *) &data_saved[0]) = ptrace (PTRACE_PEEKDATA, fpid,
addr + addr_walker, NULL);
if (errno == 0)
write (1, &data_saved[0], 1);
else
fprintf (stderr, "- [0x%08lx] invalid PTRACE_PEEKDATA\n",
addr + addr_walker), _exit(1);
}
// hexdump (data_saved, sizeof (data_saved));
if (ptrace (PTRACE_DETACH, fpid, NULL, NULL) < 0) {
perror ("ptrace PTRACE_DETACH");
exit (EXIT_FAILURE);
}
fprintf (stderr, "success. terminating.\n");
exit (EXIT_SUCCESS);
}
void
hexdump (unsigned char *data, unsigned int amount)
{
unsigned int dp, p; /* data pointer */
const char trans[] =
"................................ !\"#$%&'()*+,-./0123456789"
":;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklm"
"nopqrstuvwxyz{|}~...................................."
"....................................................."
"........................................";
for (dp = 1; dp <= amount; dp++) {
printf ("%02x ", data[dp-1]);
if ((dp % 8) == 0)
printf (" ");
if ((dp % 16) == 0) {
printf ("| ");
p = dp;
for (dp -= 16; dp < p; dp++)
printf ("%c", trans[data[dp]]);
printf ("\n");
}
}
if ((amount % 16) != 0) {
p = dp = 16 - (amount % 16);
for (dp = p; dp > 0; dp--) {
printf (" ");
if (((dp % 8) == 0) && (p != 8))
printf (" ");
}
printf (" | ");
for (dp = (amount - (16 - p)); dp < amount; dp++)
printf ("%c", trans[data[dp]]);
}
printf ("\n");
return;
}
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