What is the use of -fno-stack-protector?

c buffer stack-overflow protection callstack
touvlo2000 picture touvlo2000 · May 23, 2012 · Viewed 47.4k times · Source

I have written an application in C, and I'm trying to understand what is the purpose of the -fno-stack-protector command when compiling. For my specific application, it makes no difference if I use this command or not in terms of protecting against buffer overflow.

I've read online that the -fstack-protector and -fno-stack-protector commands enable and disable respectively the stack-smashing protector, but if I'm compiling the application myself, how can the protector be enabled beforehand? Does the usage of the command maybe depend on what system the application is running on?

Answer

R.. GitHub STOP HELPING ICE picture R.. GitHub STOP HELPING ICE · May 23, 2012

In the standard/stock GCC, stack protector is off by default. However, some Linux distributions have patched GCC to turn it on by default. In my opinion, this is rather harmful, as it breaks the ability to compile anything that's not linked against the standard userspace libraries unless the Makefile specifically disables stack protector. It would even break the Linux kernel build except that the distributions with this hack added additional hacks to GCC to detect that the kernel is being built and disable it.

Related questions

Causing a buffer Overflow with fgets

I'm experimenting with buffer overflows and try to overwrite the return address of the stack with a certain input of fgets This is the code: void foo() { fprintf(stderr, "You did it.\n"); } void bar() { char buf[20]; puts("Input:"); fgets(…

Read More
C char array initialization

I'm not sure what will be in the char array after initialization in the following ways. 1.char buf[10] = ""; 2. char buf[10] = " "; 3. char buf[10] = "a"; For case 2, I think buf[0] should be ' ', buf[1] should be '\0', and from buf[2] …

Read More
How to clear input buffer in C?

I have the following program: int main(int argc, char *argv[]) { char ch1, ch2; printf("Input the first character:"); // Line 1 scanf("%c", &ch1); printf("Input the second character:"); // Line 2 ch2 = getchar(); printf("ch1=%c, ASCII code = %d\n", ch1, …

Read More