PROSAGA码农传奇-二进制漏洞-在c中隐藏char字符串

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    你可以用它做一些数学计算，例如：
  
   <pre>
 <code>
 static unsigned char secret[] = {'m' + 10, 'y' + 10, 's' + 10, 'e' + 10, 'c' + 10, 'r' + 10, 'e' + 10, 't' + 10, 's' + 10, 't' + 10, 'r' + 10, 'i' + 10, 'n' + 10, 'g' + 10};

</code>
 </pre>
  
    因为你的秘密字符串可能在RO段：
  
   <pre>
 <code>
 char *decode(const unsigned char *str, int c)
{
 int len = 0;
 char *ml, *cl;
 while(*str != abs(c))
 len++;
 ml = malloc(len + 1);
 if(ml != NULL)
 {
 cl = ml;
 while(*str != abs(c))
 *cl++ = *str++ + c;
 *cl = 0;
 }
 return ml;
}

</code>
 </pre>
  
    当然，编写将为您编写字符串文字的脚本更容易。编码机制可能要复杂得多 - 在这个例子中，我只是微不足道
  
  
    C中的示例编码功能
  
   <pre>
 <code>
 #define VNAMEMAX 20
#define VVALUEMAX 200

typedef struct
{
    char vname[VNAMEMAX];
    char vvalue[VVALUEMAX];
}VDEF_T;

VDEF_T varialbles[] =
{
    {.vname = "mystring",.vvalue = "Something very secret"},
    {.vname = "secret_var",.vvalue = "Something even more secret" },
    {0,},
};

int code(VDEF_T *v, char *fname, int c)
{
    FILE *fp = fopen(fname, "wt");
    int result = (fp == NULL) * -1;

if (!result)
 {
 fprintf(fp, "#ifndef _MYSECRET\n#define _MYSECRET\n\n\n");
 while (!result && v->vname[0])
 {
 fprintf(fp, "static unsigned char %s[] = {\n\t\t", v->vname);
 for (int i = 0; i <= strlen(v->vvalue); i++)
 {
 if (fprintf(fp, "0x%02x,", v->vvalue[i] + c) < 0)
 {
 result = -1;
 break;
 }
 }
 if (fprintf(fp, "};\n\n") < 0) result = -1;
 v++;
 }
 if(fprintf(fp, "#endif") < 0) result = -1;
 fclose(fp);
 }
 return result;
}

</code>
 </pre>
  
    结果
     <code>
 .h
 </code>
     文件;
  
   <pre>
 <code>
 #ifndef _MYSECRET
#define _MYSECRET

static unsigned char mystring[] = {
        0x5d,0x79,0x77,0x6f,0x7e,0x72,0x73,0x78,0x71,0x2a,0x80,0x6f,0x7c,0x83,0x2a,0x7d,0x6f,0x6d,0x7c,0x6f,0x7e,0x0a,};

static unsigned char secret_var[] = {
        0x5d,0x79,0x77,0x6f,0x7e,0x72,0x73,0x78,0x71,0x2a,0x6f,0x80,0x6f,0x78,0x2a,0x77,0x79,0x7c,0x6f,0x2a,0x7d,0x6f,0x6d,0x7c,0x6f,0x7e,0x0a,};

#endif

</code>
 </pre>
</DIV>