c/troll23/troll23.c

   1 #define _GNU_SOURCE
   2 #include <stdlib.h>
   3 #include <stdio.h>
   4 #include <sys/types.h>
   5 #include <sys/syscall.h>
   6 #include <dlfcn.h>
   7 #include <stdarg.h>
   8 #include <time.h>
   9
  10 //Catch rand() calls etc...
  11 time_t time(time_t *tloc) { srand(23); return (time_t)0; }
  12 int rand(void) {        srand(23); return 23; }
  13 long int random(void) { srand(23); return 23; }
  14 int rand_r(unsigned int *seedp) { srand(23); return 23; }
  15 int random_r(struct random_data *buf, int32_t *result) { srand(23); return 23; }
  16
  17 //Catch open() calls (while redirecting filename):
  18 static const char *redirect_name(const char *name)
  19 {
  20         if(
  21                 (strcmp(name,"/dev/random") == 0) ||
  22                 (strcmp(name,"/dev/urandom") == 0)
  23         ) {
  24                 printf("REDIRECT HIT: %s\n", name);
  25                 return "/dev/zero";
  26         }
  27         return name;
  28 }
  29
  30 int open(const char *filename, int flags, ...)
  31 {
  32         //srand(23);
  33         static int (*open_orig)(const char *, int, mode_t);
  34         int ret;
  35         va_list ap;
  36         mode_t mode;
  37
  38         if (!open_orig) {
  39                 open_orig = dlsym(RTLD_NEXT, "open");
  40         }
  41
  42         va_start(ap, flags);
  43         mode = va_arg(ap, mode_t);
  44         va_end(ap);
  45
  46         ret = open_orig(redirect_name(filename), flags, mode);
  47         //ret = syscall(SYS_open,redirect_name(filename),flags,mode);
  48
  49         printf("open(\"%s\", 0x%x, %o) -> %d\n", filename, flags, mode, ret);
  50
  51         return ret;
  52 }
  53
  54 int open64(const char *filename, int flags, ...)
  55 {
  56         //srand(23);
  57         static int (*open64_orig)(const char *, int, mode_t);
  58         int ret;
  59         va_list ap;
  60         mode_t mode;
  61
  62         if (!open64_orig) {
  63                 open64_orig = dlsym(RTLD_NEXT, "open64");
  64         }
  65
  66         va_start(ap, flags);
  67         mode = va_arg(ap, mode_t);
  68         va_end(ap);
  69
  70         ret = open64_orig(redirect_name(filename), flags, mode);
  71         //ret = syscall(SYS_open64,redirect_name(filename),flags,mode);
  72
  73         printf("open64(\"%s\", 0x%x, %o) -> %d\n", filename, flags, mode, ret);
  74
  75         return ret;
  76 }