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Questions  |  score: 4  |  4.30 5.61 6.91 |  Solved By 276 People  |  50641 views  |  since Mar 24, 2012 - 01:30:23

Choose your Path II (Linux, Exploit, Warchall)

Choose your Path II
This is the level11 mini challenge found in /home/level/11/ on the warchall box.
The sequel to Choose your Path.
You can view the source here.

Proudly presented by Mart and the warchall staff.
GeSHi`ed C code for choose_your_path2.c
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h> 
#define BUFSIZE 256
 
int escape_single_quotes(char *to, char *from, int max)
{  int l= 0;
 
  for (;*from;from++)
  {
    switch (*from)    {
      case '\'':
        if (l>=max-4) return 0; // not enough space for escaped chars!
// replace ' with '\''
        *(to++)= '\'';        *(to++)= '\\';
        *(to++)= '\'';
        l += 3;
      default:
        if (l>=max-1) return 0; // not enough space for this char!        *(to++)= *from;
        l++;
    }
  }
   *to= 0;
 
  return 1;
}
 int main(int argc, char *argv[])
{
  FILE *fp;
  char buf[BUFSIZE];
  char escaped_name[BUFSIZE];  char *filename;
  int lines, chars, cpl;
 
  setregid(1012, 1012); // set real and effective GID to level11
   if (argc != 2)
  {
    fprintf(stderr, "Usage: %s filename\n", argv[0]);
    exit(EXIT_FAILURE);
  }  
  filename= argv[1];
  printf("Counting %s ... \n", filename);
 
  if (!escape_single_quotes(escaped_name, filename, BUFSIZE))  {
    fprintf(stderr, "Escaped filename is too long!\n");
    exit(EXIT_FAILURE);
  }
   if (snprintf(buf, BUFSIZE, "wc -l '%s'", escaped_name)>=BUFSIZE)
  {
    fprintf(stderr, "Filename %s is too long!\n", filename);
    exit(EXIT_FAILURE);
  } 
  fp= popen(buf, "r");
  if (!fp)
  {
    fprintf(stderr, "Command execution failed! Sorry!\n");    exit(EXIT_FAILURE);
  }
  if (1!=fscanf(fp, "%d", &lines))
  {
    fprintf(stderr, "Cannot scan! Sorry!\n");  }
  pclose(fp);
 
  snprintf(buf, BUFSIZE, "wc -c '%s'", escaped_name);
  fp= popen(buf, "r");  if (!fp)
  {
    fprintf(stderr, "Command execution failed! Bummer!\n");
    exit(EXIT_FAILURE);
  }  if (1!=fscanf(fp, "%d", &chars))
  {
    fprintf(stderr, "Cannot scan! Sorry!\n");
  }
  pclose(fp); 
  cpl= chars/lines;
 
  printf("Chars per line is %d.\n", cpl);
   return EXIT_SUCCESS;
}
 
 
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