Assertion failed! esp32

[OsamaBillah]

Hi, I'm learing to check how bufferoverflow happen what kind of mistake the developers do. and for that my supervisor told me to write the code and he helped me. As we know first we have to perform windowoverflow and then bufferoverflow. and for that i worte below code:

Code: [Select all] [Expand/Collapse]

1. #include <stdio.h>
2. #include <stdbool.h>
3. #include <unistd.h>
4. #include <string.h>
5.  
6.  
7. void function_A(){
8.  
9.     asm("");
10.  
11. }
12.  
13. void function_B(){
14.     function_A();
15. }
16.  
17.  
18. char myNumbers[] = {1, 2, 3, 4,5, 6, 7, 8,9, 10, 11, 12,13, 14, 15, 16,17, 18, 19, 20,21, 22, 23, 24,25, 26, 27, 28,29, 30, 31, 32,33, 34, 35, 36,
19.         1, 2, 3, 4,5, 6, 7, 8,9, 10, 11, 12,13, 14, 15, 16,17, 18, 19, 20,21, 22, 23, 24,25, 26, 27, 28,29, 30, 31, 32,33, 34, 35, 36,
20.         1, 2, 3, 4,5, 6, 7, 8,9, 10, 11, 12,13, 14, 15, 16,17, 18, 19, 20,21, 22, 23, 24,25, 26, 27, 28,29, 30, 31, 32,33, 34, 35, 36,
21.         };
22.  
23. void function_C(){
24.     function_B();
25.  
26.     char small_array[] = {'a','b','c','d'};
27.     strcpy(small_array, myNumbers);
28.  
29. }
30.  
31. void function_D(){
32.     function_C();
33. }
34.  
35.  
36. void app_main(void)
37. {
38.     function_D();
39.  
40. }

GeSHi © Codebox Plus Extension

error::

Assertion failed!


Program: C:\Espressif\tools\openocd-esp32\v0.11.0-esp32-20221026\openocd-esp32\bin\openocd.exe
File: ../src/flash/nor/esp_flash.c, Line 1129


Expression: sw_bp->insn_sz <= sizeof(sw_bp->insn)

Note::

Addresses are calculated correctly.

[mbratch]

I'm not sure what your question is.

The example code will overwrite the stack and cause undefined behaviour.

[OsamaBillah]

so basically I want to learn how bufferoverflow attack works. and for that i worte the mention code. this code first create windowoverflow and then come to underflow and then to doubleexception so that i know that overflow happend and this is what i want. but my code while debugging and when debugger comes to function_c

Code: [Select all] [Expand/Collapse]

1. void function_C(){
2.     function_B();
3.  
4.     char small_array[] = {'a','b','c','d'};
5.     strcpy(small_array, myNumbers);
6.  
7. }

GeSHi © Codebox Plus Extension

it has to go to function_B so that windowoverflow happed first and then the rest. but it directly comes to thee strcpy so the other steps missed and then it give me the Assertion failed

[ESP_Sprite]

That's because the compiler sees a bunch of your functions do nothing or very little and inlines them or skips them alltogether. proof.

[mbratch]

That's because the compiler sees a bunch of your functions do nothing or very little and inlines them or skips them alltogether. proof.

Is there a compiler option the OP can set which turns off all the optimizations?

[OsamaBillah]

That's what I'm looking for. that somehow I can turns off all the optimizations. then maybe it can work.

[MicroController]

asm volatile (""); makes a function look "not empty" to the compiler, and __attribute__((noinline)) reduces the chances of a function being inlined.

[MicroController]

this code first create windowoverflow and then ...

The ESP32's LX6 has 64 registers and gcc uses the CALL8 ABI, so each nested function call 'uses up' only 8 of the 64 registers.