Cook: security things in Linux v4.17
Kees Cook describes
the security-oriented changes included in the 4.17 kernel release.
"
It was possible that old memory contents would live in a new process’s kernel stack. While normally not visible, “uninitialized” memory read flaws or read overflows could expose these contents (especially stuff “deeper” in the stack that may never get overwritten for the life of the process). To avoid this, I made sure that new stacks were always zeroed. Oddly, this “priming” of the cache appeared to actually improve performance, though it was mostly in the noise."