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 <unistd.h>
   8 #include <stdarg.h>
   9 #include <time.h>
  10 #include <string.h>
  11
  12 #define i { srand(23); printf("%s();\n",__func__); }
  13
  14 //Catch rand() calls etc...
  15 int rand(void) { i; return 23; }
  16 long int random(void) { i; return 23; }
  17 int rand_r(unsigned int *seedp) { i; return 23; }
  18 int random_r(struct random_data *buf, int32_t *result) { i; return 23; }
  19 //Time
  20 time_t time(time_t *tloc) { i; return (time_t)0; }
  21 int clock_gettime(clockid_t clk_id, struct timespec *tp) { i; tp->tv_nsec=0; tp->tv_sec=0; return (time_t)0; }
  22 //OpenSSL (not working i guess...)
  23 int RAND_bytes(unsigned char *buf, int num) { i; memset(buf, 23, (size_t) num); return 23; }
  24 int RAND_pseudo_bytes(unsigned char *buf, int num) { i; memset(buf, 23, (size_t) num); return 23; }
  25 int FIPS_rand_bytes(unsigned char *buf, int num) { i; memset(buf, 23, (size_t) num); return 23; }
  26 int FIPS_rand_pseudo_bytes(unsigned char *buf, int num) { i; memset(buf, 23, (size_t) num); return 23; }
  27 //IDs
  28 pid_t getpid(void) { i; return (pid_t)0; }
  29 uid_t getuid(void) { i; return (uid_t)0; }
  30 gid_t getgid(void) { i; return (gid_t)0; }
  31 uid_t geteuid(void) { i; return (uid_t)0; }
  32 gid_t getegid(void) { i; return (gid_t)0; }
  33
  34 //Catch open() calls (while redirecting filename):
  35 static const char *redirect_name(const char *name)
  36 {
  37         if(
  38                 (strcmp(name,"/dev/random") == 0) ||
  39                 (strcmp(name,"/dev/urandom") == 0)
  40         ) {
  41                 printf("REDIRECT HIT: %s\n", name);
  42                 return "/dev/zero";
  43         }
  44         return name;
  45 }
  46
  47 int open(const char *filename, int flags, ...)
  48 {
  49         //srand(23);
  50         static int (*open_orig)(const char *, int, mode_t);
  51         int ret;
  52         va_list ap;
  53         mode_t mode;
  54
  55         if (!open_orig) {
  56                 open_orig = dlsym(RTLD_NEXT, "open");
  57         }
  58
  59         va_start(ap, flags);
  60         mode = va_arg(ap, mode_t);
  61         va_end(ap);
  62
  63         ret = open_orig(redirect_name(filename), flags, mode);
  64         //ret = syscall(SYS_open,redirect_name(filename),flags,mode);
  65
  66         printf("open(\"%s\", 0x%x, %o) -> %d\n", filename, flags, mode, ret);
  67
  68         return ret;
  69 }
  70
  71 int open64(const char *filename, int flags, ...)
  72 {
  73         //srand(23);
  74         static int (*open64_orig)(const char *, int, mode_t);
  75         int ret;
  76         va_list ap;
  77         mode_t mode;
  78
  79         if (!open64_orig) {
  80                 open64_orig = dlsym(RTLD_NEXT, "open64");
  81         }
  82
  83         va_start(ap, flags);
  84         mode = va_arg(ap, mode_t);
  85         va_end(ap);
  86
  87         ret = open64_orig(redirect_name(filename), flags, mode);
  88         //ret = syscall(SYS_open64,redirect_name(filename),flags,mode);
  89
  90         printf("open64(\"%s\", 0x%x, %o) -> %d\n", filename, flags, mode, ret);
  91
  92         return ret;
  93 }