MIT researchers uncover ‘unpatchable’ flaw in Apple M1 chips

Re:MIT researchers uncover ‘unpatchable’ flaw in Apple M1 chips by gjsman-1000 on Friday June 10, 2022 @12:08PM (#31696075)

Also important to mention that PAC is a new ARMv8.2 feature and previous versions of ARM have no PAC system at all. The only ARM chips with PAC are from Apple and AWS Graviton3 - any other chip has no hardware protections against this.

So ultimately, right now, it's just downgrading a very new protection to as if it didn't exist, which is exactly how 98% of ARM chips in the world operate right now. Not great, not terrible, A for effort, was worth a shot, speculative execution breaks everything.

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Re:MIT researchers uncover ‘unpatchable’ flaw in Apple M1 chips by adrian_b on Friday June 10, 2022 @03:18PM (#31698330)

Besides the Apple CPUs and Graviton 3 (Armv8.4-A), the cores introduced by ARM in 2021 and present in some 2022 smartphones (Cortex-X2, Cortex-A710, Cortex-A510), which implement Armv9.0-A, also support PAC.

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Re:MIT researchers uncover ‘unpatchable’ flaw in Apple M1 chips by fulafel on Saturday June 11, 2022 @06:12AM (#31703358)

The doc in the kernel tree is dated 2017, so it's percolated to products quite slowly: https://www.kernel.org/doc/html/latest/arm64/pointer-authent...

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Re:MIT researchers uncover ‘unpatchable’ flaw in Apple M1 chips by shp0ngle on Friday June 10, 2022 @11:52PM (#31701762)

Ah thanks, this finally makes sense in context

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Re:MIT researchers uncover ‘unpatchable’ flaw in Apple M1 chips by gjsman-1000 on Friday June 10, 2022 @02:38PM (#31697853)

Edit: Correction, ARMv8.3, not ARMv8.2.

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