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/* memory dump utility
* -scut
*/
#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>
#include <libgen.h> /* basename */
void
hexdump (unsigned char *data, unsigned int amount);
int
main (int argc, char *argv[])
{
pid_t fpid; /* child pid, gets ptraced */
char * argv0;
struct user regs; /* PTRACE pulled registers */
unsigned long int addr, /* segment start address */
addr_end, /* segment end address */
len; /* length of segment */
unsigned long int addr_walker, /* walker to dump memory */
eip; /* current childs eip */
/* array to temporarily store data into */
unsigned char data_saved[sizeof (unsigned long int)];
/* file to read mapping information */
FILE * map_f; /* /proc/<pid>/maps stream */
unsigned char map_line[256]; /* one line each from map */
/* data for the dump files */
FILE * dump_f; /* stream */
char dump_name[64]; /* filename buffer */
if (argc < 3 || sscanf (argv[1], "0x%lx", &eip) != 1) {
printf ("usage: %s <eip> <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);
}
argv0 = argv[2];
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[2]);
close (1);
dup2 (2, 1);
execve (argv[2], &argv[2], NULL);
/* failed ? */
perror ("execve");
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);
}
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);
}
fprintf (stderr, "0x%08lx\n", regs.regs.eip);
} while (regs.regs.eip != eip);
fprintf (stderr, "MEMDUMP: eip @ 0x%08lx, dumping...\n", eip);
snprintf (dump_name, sizeof (dump_name), "%s.regs",
basename (argv0));
dump_name[sizeof (dump_name) - 1] = '\0';
dump_f = fopen (dump_name, "w");
if (dump_f == NULL) {
perror ("fopen dumpfile regs");
exit (EXIT_FAILURE);
}
fprintf (dump_f, "eax = 0x%08lx\n", regs.regs.eax);
fprintf (dump_f, "ebx = 0x%08lx\n", regs.regs.ebx);
fprintf (dump_f, "ecx = 0x%08lx\n", regs.regs.ecx);
fprintf (dump_f, "edx = 0x%08lx\n", regs.regs.edx);
fprintf (dump_f, "esi = 0x%08lx\n", regs.regs.esi);
fprintf (dump_f, "edi = 0x%08lx\n", regs.regs.edi);
fprintf (dump_f, "ebp = 0x%08lx\n", regs.regs.ebp);
fprintf (dump_f, "esp = 0x%08lx\n", regs.regs.esp);
fprintf (dump_f, "eflags = 0x%08lx\n", regs.regs.eflags);
fprintf (dump_f, "xcs = 0x%08lx\n", regs.regs.xcs);
fprintf (dump_f, "xds = 0x%08lx\n", regs.regs.xds);
fprintf (dump_f, "xes = 0x%08lx\n", regs.regs.xes);
fprintf (dump_f, "xss = 0x%08lx\n", regs.regs.xss);
fclose (dump_f);
snprintf (map_line, sizeof (map_line), "/proc/%d/maps", fpid);
map_line[sizeof (map_line) - 1] = '\0';
map_f = fopen (map_line, "r");
if (map_f == NULL) {
perror ("fopen map-file");
exit (EXIT_FAILURE);
}
while (fgets (map_line, sizeof (map_line), map_f) != NULL) {
char map_perm[8];
if (sscanf (map_line, "%08lx-%08lx %7[rwxp-] ",
&addr, &addr_end, map_perm) != 3)
{
perror ("invalid map-line");
exit (EXIT_FAILURE);
}
if (addr_end < addr) {
fprintf (stderr, "sanity required, not so: "
"addr = 0x%08lx, addr_end = 0x%08lx",
addr, addr_end);
exit (EXIT_FAILURE);
}
len = addr_end - addr;
map_perm[sizeof (map_perm) - 1] = '\0'; /* ;-) */
fprintf (stderr, "MEMDUMP: -> 0x%08lx (0x%08lx bytes, "
"perm %s)\n", addr, len, map_perm);
snprintf (dump_name, sizeof (dump_name),
"%s.0x%08lx.0x%08lx.%s",
basename (argv0), addr, len, map_perm);
dump_name[sizeof (dump_name) - 1] = '\0';
dump_f = fopen (dump_name, "wb");
if (dump_f == NULL) {
perror ("fopen dumpfile");
exit (EXIT_FAILURE);
}
/* save data, assuming addr is page aligned */
for (addr_walker = 0 ; addr_walker < len ;
addr_walker += sizeof (data_saved))
{
errno = 0;
*((unsigned long int *) &data_saved[0]) =
ptrace (PTRACE_PEEKDATA, fpid,
addr + addr_walker, NULL);
if (errno == 0 && fwrite (&data_saved[0], 1, 4,
dump_f) != 4)
{
perror ("fwrite dumpfile");
exit (EXIT_FAILURE);
} else if (errno != 0) {
fprintf (stderr,
"[0x%08lx] invalid PTRACE_PEEKDATA\n",
addr + addr_walker);
exit (EXIT_FAILURE);
}
}
fclose (dump_f);
}
fclose (map_f);
if (ptrace (PTRACE_DETACH, fpid, NULL, NULL) < 0) {
perror ("ptrace PTRACE_DETACH");
exit (EXIT_FAILURE);
}
fprintf (stderr, "MEMDUMP: 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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