Revised Intel Shadow Stack Support May Be Ready For Linux 6.5

Written by Michael Larabel in Intel on 19 June 2023 at 07:55 AM EDT. 5 Comments
Intel engineers had sent in Shadow Stack support for Linux 6.4 as this feature part of Control-flow Enforcement Technology (CET) but it hit a last-minute snag during the merge window with issues raised by Linus Torvalds. Now it looks like the cleaned-up Shadow Stack code will be re-submitted for the upcoming Linux 6.5 cycle.

Prior to the weekend tip/tip.git's x86/shstk branch pulled in all of the latest Intel Shadow Stack patches. With those new patches now making their way back into TIP.git, it's believed they will be re-submitted for the upcoming Linux 6.5 merge window.

Shadow Stack take 2

Assuming nothing crazy happens this week, Linux 6.4 stable is likely to be released next weekend and that in turn will mark the start of the Linux 6.5 merge window... Otherwise it would be dragged out an extra week if Linux 6.4-rc8 is instead warranted.

In any event now that Linus Torvalds' concerns are addressed, this Shadow Stack security functionality should be merged for Linux 6.5 to benefit Intel Tiger Lake CPUs and newer. Shadow Stack functionality is intended to provide return address protection to defend against ROP attacks.
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