APPLIED: [PATCH 0/1][SRU][B] CVE-2018-18281 - stale TLB entries via mremap()

Khaled Elmously khalid.elmously at canonical.com
Thu Jan 10 05:35:49 UTC 2019


On 2018-12-06 22:14:29 , Tyler Hicks wrote:
> https://people.canonical.com/~ubuntu-security/cve/2018/CVE-2018-18281.html
> 
>  Since Linux kernel version 3.2, the mremap() syscall performs TLB flushes
>  after dropping pagetable locks. If a syscall such as ftruncate() removes
>  entries from the pagetables of a task that is in the middle of mremap(), a
>  stale TLB entry can remain for a short time that permits access to a
>  physical page after it has been released back to the page allocator and
>  reused. This is fixed in the following kernel versions: 4.9.135, 4.14.78,
>  4.18.16, 4.19.
> 
> Clean cherry pick to Bionic. I tested this change using the --mremap
> stressor of stress-ng.
> 
> Tyler
> 
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