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disable userfaultfd for all unprivileged users #5167

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merged 1 commit into from
Aug 12, 2021

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leodido
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@leodido leodido commented Aug 12, 2021

The userfaultfd system call (and subsequent API) can be misused making it easier to exploit existing use-after-free (and similar) bugs that might otherwise only make a short window or race condition available.

Thus, we here disable it (on the host nodes) for unprivileged users through the global sysctl knob "vm.unprivileged_userfaultfd".

Fixes #5156

Signed-off-by: Leo Di Donato [email protected]

The `userfaultfd` syscall (and subsequent API) can be misued making easier to exploit existing use-after-free (and similar) bugs that might otherwise only make a short window or race condition available.

Thus, we here disable it (on the host nodes) for unprivileged users through the global sysctl knob "vm.unprivileged_userfaultfd".

Signed-off-by: Leo Di Donato <[email protected]>
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/lgtm

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LGTM label has been added.

Git tree hash: bec2f70b59adb39d07f221e0d3a0ed1a2158550e

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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: csweichel

Associated issue: #5156

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leodido commented Aug 12, 2021

/hold

@roboquat roboquat merged commit 64f4677 into main Aug 12, 2021
@roboquat roboquat deleted the leo/disable-userfaultfd-unprivileged branch August 12, 2021 10:52
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Disable userfaultfd for unprivileged users
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