AMD and Intel CPU security bugs bring Linux patches

It's not really a Linux problem, but as is so often the case, Linux kernel developers have to clean up after AMD and Intel. It happened again with the chipmakers' latest CPU vulnerabilities: AMD Inception and Intel Downfall. To fix these, Linux creator Linus Torvalds has released a new set of patches. Oddly, both are speculative side-channel attacks, which can lead to privileged data leakage to unprivileged processes. Torvalds described them as "yet another issue where userspace poisons a microarchitectural structure which can then be used to leak privileged information through a side channel." Also: How to choose the right Linux desktop distribution for you Does that sound familiar? It will be to Linux security experts. Yes, it's yet another example of the kind of security vulnerabilities that made Intel's Meltdown and Spectre infamous in Linux circles. Fortunately, unlike those two earlier cases, developers this time knew well in advance that there was trouble with the silicon, so the patches came out before news of the latest holes appeared. In this recent merge, Torvalds and company incorporated kernel-side measures that counteract AMD's Speculative Return Address Stack (RAS) overflow vulnerability to its Zen 3 and Zen 4 architectures. This vulnerability allows userspace to contaminate a microarchitectural structure, which can subsequently be exploited to siphon privileged information via a side channel. AMD will tell you it's not that big a deal: The chip giant believes ...