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Core 2 Duo: Bugged Beyond Belief?
Developers are worried the unusual number of processor bugs in Intel's latest will be exploited by black hats.
Theo de Raadt is worried. The growing number of unfixed bugs in Intel's Core 2 Duo processors are going to become black hat attack vectors, writes the uncompromising OpenBSD lead to their mailing list.
These processors are buggy as hell, and some of these bugs don't just cause development / debugging problems, but will *ASSUREDLY* be exploitable from userland code.
The current full errata from Intel is available here.
The MMU simply does not operate as specified / implemented in previous generations of x86 hardware. Some of the bugs are along the lines of 'buffer overflow' where a write-protect or non-execute bit for a page table entry is ignored. Others are floating point instruction non-coherencies or memory corruptions - outside of the range of permitted writing for the process - running common instruction sequences.
We bet there are many more errata not yet announced - every month this file gets larger. Intel understate the impact of these errata very significantly. Almost all operating systems will run into these bugs.
All of this is just unbelievable to many of us.
Not Just Intel
Intel aren't the only culprits, insists de Raadt. All the x86 processors currently on the market are bugged beyond belief. Even AMD bug lists are growing geometrically and their concomitant support for 'support' is proportionately waning.
At this time, I cannot recommend purchase of any machines based on the Intel Core 2 until these issues are dealt with (which I suspect will take more than a year). Intel must become more transparent.
Linus: 'Calm Down!'
Linux head Linus Torwalds doesn't believe these bugs are anything to lose sleep over.
The biggest problem is Intel should just have documented the TLB behavior better. The Core 2 changes are kind of gray area and the old documentation simply didn't talk about the higher level page table structures and the caching rules for them. So that part is just a good clarification and while it could be called a 'bug' just because older CPUs didn't do that caching I don't think it's errata per se.
I'd expect other CPUs to generally have more errata than most commodity x86 chips.