C# creating buffer overflow -

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i'm trying create buffer overflow c# school project:

unsafe {     fixed (char* ptr_str = new char[6] {'h', 'a', 'l', 'l', 'o', ','})     {         fixed (char* ptr_str2 = new char[6] {'w', 'e', 'r', 'e', 'l', 'd'})         {             fixed (char* ptr_str3 = new char[6] {'!', '!', '!', '!', '!', '!'})             {                 (int = 0; < 8; i++)                 {                     ptr_str2[i] = 'a';                 }                  (int = 0; < 6; i++)                 {                     this.label2.text += ptr_str[i];                     this.label3.text += ptr_str2[i];                     this.label4.text += ptr_str3[i];                 }             }         }     } }

i thought flood ptr_str2 , thereby overwriting chars in ptr_str. not seem happen. execute values in ptr_str not overwritten.

can achieving this? don't understand i'm doing wrong.

you missing fact arrays objects themselves. have object header managed reference type , private field stores array size. have overwrite first before start overwriting array elements. on 32-bit machine, you'll start overwriting first element of ptr_str2 this:

                        (int = 0; < 13; i++) {                             ptr_str[i] = 'a';                         }

of course, had 13.

observe setting breakpoint on loop. debug + windows + memory + memory 1, type "ptr_str" in address box. step code see memory getting changed. you'll see ptr_str2 right after that, 4 bytes syncblk, 4 bytes method table pointer , 4 bytes array length. 12 bytes total, 6 chars.


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