Messages in this thread | | | Subject | Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map kernel in user mode | From | Daniel Gruss <> | Date | Mon, 8 May 2017 16:19:29 +0200 |
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On 08.05.2017 16:09, Thomas Garnier wrote: >> Just to correct my answer here as well: Although we experimented with fixed >> mappings for per-cpu addresses, the current patch does not incorporate this >> yet, so it indeed still leaks. However, it is not a severe problem. The >> mapping of the required (per-cpu) variables would be at a fixed location in >> the user CR3, instead of the ones that are used in the kernel. > > Why do you think it should be at a fixed location in the user CR3? I > see that you just mirror the entries. You also mirror > __entry_text_start / __entry_text_end which is part of the binary so > will leak the base address of the kernel. Maybe I am missing > something.
As I said, the current patch does not incorporate this yet, so yes, this part currently still leaks because we did not implement it yet.
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