prefast/MartLubbers_prefast_exercise.cpp

   1 /*
   2  * Mart Lubbers (s4109503)
   3  */
   4 #include "stdafx.h"
   5 #include "stdio.h"
   6 #undef __analysis_assume
   7 #include <CodeAnalysis\SourceAnnotations.h>
   8
   9 #define BUF_SIZE 100
  10 #define STR_SIZE 200
  11
  12 void zeroing();
  13
  14 char *my_alloc(size_t size)
  15 {
  16         //FIXED
  17         char *ch  = (char *)calloc(size, 1);
  18         if (ch == NULL){
  19                 perror("malloc");
  20                 exit(EXIT_FAILURE);
  21         }
  22         return ch;
  23 }
  24
  25 bool input([SA_Post(Tainted=SA_Yes)] _Out_cap_c_(BUF_SIZE) char *buf)
  26 {
  27         //FIXED
  28         return (gets_s(buf, BUF_SIZE) != NULL) ? true : false;
  29 }
  30
  31 [returnvalue:SA_Post(Tainted=SA_Yes)] char *do_read()
  32 {
  33         //FIXED
  34         char *buf = my_alloc(STR_SIZE);
  35         printf("Allocated a string at %p", buf);
  36         if(!input(buf)){
  37                 puts("Error!");
  38                 exit(EXIT_FAILURE);
  39         }
  40         if (buf[0] == '\0')
  41                 printf("empty string");
  42         return buf;
  43 }
  44
  45 void copy_data([SA_Pre(Tainted=SA_Yes)]_In_count_c_(STR_SIZE) char *buf1, [SA_Post(Tainted=SA_Yes)] _Out_cap_c_(STR_SIZE) char *buf2)
  46 {
  47         memcpy(buf2,buf1,STR_SIZE);
  48         buf2[STR_SIZE-1] = NULL; // null terminate, just in case
  49 }
  50
  51 int execute([SA_Pre(Tainted=SA_No)] _In_count_c_(BUF_SIZE) char *buf)
  52 {
  53         return system(buf); // pass buf as command to be executed by the OS
  54 }
  55
  56 void validate([SA_Pre(Tainted=SA_Yes)][SA_Post(Tainted=SA_No)] _Inout_count_c_(BUF_SIZE) char *buf)
  57 {
  58         // This is a magical validation method, which turns tainted data
  59         // into untainted data, for which the code not shown.
  60         //
  61         // A real implementation might for example use a whitelist to filter
  62         // the string.
  63 }
  64
  65 _Check_return_ int test_ready()
  66 {
  67         // code not shown
  68         return 1;
  69 }
  70
  71 int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
  72 {
  73         char *buf1 = do_read();
  74         char *buf2 = my_alloc(BUF_SIZE);
  75         zeroing();
  76         //FIXED
  77         if(test_ready() != 0){
  78                 printf("Test not ready\n");
  79                 exit(EXIT_FAILURE);
  80         }
  81         //FIXED
  82         validate(buf1);
  83         execute(buf1);
  84
  85         char* buf3 = do_read();
  86         copy_data(buf3, buf2);
  87         //FIXED
  88         validate(buf2);
  89         execute(buf2);
  90
  91         char *buf4 = do_read();
  92         //FIXED
  93         validate(buf4);
  94         execute(buf4);
  95 }
  96
  97 // *****************************************************************
  98
  99 void zero(_Out_cap_(len) int *buf, int len)
 100 {
 101         int i;
 102         //FIXED
 103         for(i = 0; i < len; i++)
 104                 buf[i] = 0;
 105 }
 106
 107 void zeroboth(
 108                 _Out_cap_(len) int *buf, int len,
 109                 _Out_cap_(len3) int *buf3, int len3)
 110 {
 111         int *buf2 = buf;
 112         int len2 = len;
 113         zero(buf2, len2);
 114         zero(buf3, len3);
 115 }
 116
 117 void zeroboth2(_Out_cap_(len3) int *buf, int len, _Out_cap_(len) int *buf3, int len3)
 118 {
 119         zeroboth(buf, len3, buf3, len);
 120 }
 121
 122 void zeroing()
 123 {
 124         int elements[200];
 125         int oelements[100];
 126         //FIXED
 127         zeroboth2(elements, 100, oelements, 200);
 128 }