Missing error handling for a large allocation

[insuyun]

Hi.

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <malloc.h>

void* p[256];
uintptr_t buf[256];

int main() {
  p[0] = malloc(-8);
  fprintf(stderr, "%p\n", p[0]);
}

This program will crash if we run it with SlimGuard.
The reason is that SlimGuard checks mark_used without validating the return value from previous call, which could be zero( https://github.com/ssrg-vt/SlimGuard/blob/master/src/slimguard.c#L409)

Best,
Insu Yun.

[olivierpierre]

Hello, thank you very much for reporting this bug, you are correct, and it should be fixed in this commit.

Best,

Pierre