FireFox Nightly Enables W^X

The security policy W^X, also known as “Write XOR Execute” and relates to the memory that defines memory pages as either writable or executable, but not both and is a feature present in the OpenBSD operating systems since 2003 and helps to alleviates certain buffer overflow attacks by ensuring that the stack is not executable, arbitrary code injected into it will not execute but instead cause the program to terminate. Most JIT (Just in Time) compilers use RWX (read-write-execute) permissions for memory pages which allows the compiler to patch code without performance overhead. This is the case for Firefox’s current JIT compiler, but also for Chrome’s or Safari’s compiler. Continue reading this story here.