CVE-2024-35996

In the Linux kernel, the following vulnerability has been resolved:

cpu: Re-enable CPU mitigations by default for !X86 architectures

Rename x86s to CPU_MITIGATIONS, define it in generic code, and force it on for all architectures exception x86. A recent commit to turn mitigations off by default if SPECULATION_MITIGATIONS=n kinda sorta missed that cpu_mitigations is completely generic, whereas SPECULATION_MITIGATIONS is x86-specific.

Rename x86s SPECULATIVE_MITIGATIONS instead of keeping both and have it select CPU_MITIGATIONS, as having two configs for the same thing is unnecessary and confusing. This will also allow x86 to use the knob to manage mitigations that arent strictly related to speculative execution.

Use another Kconfig to communicate to common code that CPU_MITIGATIONS is already defined instead of having x86s menu depend on the common CPU_MITIGATIONS. This allows keeping a single point of contact for all of x86s mitigations, and its not clear that other architectures want to allow disabling mitigations at compile-time.

Affected Software

References

• https://git.kernel.org/stable/c/36b32816fbab267611f073223f1b0b816ec5920f
• https://git.kernel.org/stable/c/38f17d1fbb5bfb56ca1419e2d06376d57a9396f9
• https://git.kernel.org/stable/c/8292f4f8dd1b005d0688d726261004f816ef730a
• https://git.kernel.org/stable/c/af6d6a923b40bf6471e44067ac61cc5814b48e7f
• https://git.kernel.org/stable/c/fd8547ebc187037cc69441a15c1441aeaab80f49
• https://git.kernel.org/stable/c/fe42754b94a42d08cf9501790afc25c4f6a5f631
• https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html