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Issue metadata

Status: Duplicate
Merged: issue 798431
Owner:
Closed: Jan 2018
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: Chrome
Pri: ----
Type: Bug-Security



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CVE-2017-16995 CVE-2017-16996: Security: Arbitrary read/write in kernel due to eBPF verifier bugs

Project Member Reported by mnissler@chromium.org, Dec 22 2017

Issue description

See https://bugs.chromium.org/p/project-zero/issues/detail?id=1454

Can be used for privilege escalation to kernel/root.

I don't think we have CONFIG_BPF_SYSCALL enabled, so the exploit vector used in the report and POC https://github.com/brl/grlh/blob/master/get-rekt-linux-hardened.c shouldn't work. Not sure about whether there are other eBPF uses, hopefully groeck@ will know more.

Fix is coming in via the net tree per https://bugs.chromium.org/p/project-zero/issues/detail?id=1454#c7

Looks like something we would want to patch even though BPF is currently off just in case we decide to enable it at a later point.
 
Also see http://seclists.org/oss-sec/2017/q4/429

The description there suggests that only 4.9+ is affected.
And here are a couple CVEs that got allocated: CVE-2017-16995 CVE-2017-16996
Project Member

Comment 3 by sheriffbot@chromium.org, Dec 22 2017

Status: Assigned (was: Unconfirmed)

Comment 4 by groeck@chromium.org, Dec 22 2017

Summary: CVE-2017-16995 CVE-2017-16996: Security: Arbitrary read/write in kernel due to eBPF verifier bugs (was: Security: Arbitrary read/write in kernel due to eBPF verifier bugs)

Comment 5 by groeck@chromium.org, Dec 22 2017

Cc: wonderfly@google.com
Status: ExternalDependency (was: Assigned)
As per description and #1, only v4.9+ are affected which are not shipping. Given that, we'll pull in the fixes through stable tree merges. Marking ExternalDependency for tracking.

As far as I can tell, you cannot hit eBPF without the bpf(2) syscall. Guenter's approach SGTM.
Mergedinto: 798431
Status: Duplicate (was: ExternalDependency)
Will be fixed with merge of v4.14.10 ( crbug.com/798431 ). Marking as duplicate.

#6: Lakitu has CONFIG_BPF_SYSCALL enabled.

Cc: adityakali@google.com
Yes, CONFIG_BPF_SYSCALL was recently enabled on lakitu per user request (though we don't allow unprivileged user to make bpf syscalls). Getting the patch through a 4.14 merge sounds good.
Project Member

Comment 10 by sheriffbot@chromium.org, Apr 11 2018

Labels: -Restrict-View-SecurityTeam allpublic
This bug has been closed for more than 14 weeks. Removing security view restrictions.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

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