lkml.org 
[lkml]   [2017]   [May]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map kernel in user mode
    From
    Date
    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.

    \
     
     \ /
      Last update: 2017-05-08 16:20    [W:4.465 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site