1 //===-- enable_execute_stack_test.c - Test __enable_execute_stack ----------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 11 #include <stdio.h> 12 #include <string.h> 13 #include <stdint.h> 14 #include <sys/mman.h> 15 16 17 18 extern void __clear_cache(void* start, void* end); 19 extern void __enable_execute_stack(void* addr); 20 21 typedef int (*pfunc)(void); 22 func1()23int func1() 24 { 25 return 1; 26 } 27 func2()28int func2() 29 { 30 return 2; 31 } 32 33 34 35 main()36int main() 37 { 38 unsigned char execution_buffer[128]; 39 // mark stack page containing execution_buffer to be executable 40 __enable_execute_stack(execution_buffer); 41 42 // verify you can copy and execute a function 43 memcpy(execution_buffer, (void *)(uintptr_t)&func1, 128); 44 __clear_cache(execution_buffer, &execution_buffer[128]); 45 pfunc f1 = (pfunc)(uintptr_t)execution_buffer; 46 if ( (*f1)() != 1 ) 47 return 1; 48 49 // verify you can overwrite a function with another 50 memcpy(execution_buffer, (void *)(uintptr_t)&func2, 128); 51 __clear_cache(execution_buffer, &execution_buffer[128]); 52 pfunc f2 = (pfunc)(uintptr_t)execution_buffer; 53 if ( (*f2)() != 2 ) 54 return 1; 55 56 return 0; 57 } 58