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Issue metadata

Status: WontFix
Owner:
Closed: Jan 2018
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: Chrome
Pri: 2
Type: Bug-Security



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CVE-2017-17862 CrOS: Vulnerability reported in Linux kernel

Project Member Reported by vomit.go...@appspot.gserviceaccount.com, Jan 10 2018

Issue description

VOMIT (go/vomit) has received an external vulnerability report for the Linux kernel. 

Advisory: CVE-2017-17862
  Details: http://vomit.googleplex.com/advisory?id=CVE/CVE-2017-17862
  CVSS severity score: 4.9/10.0
  Description:

kernel/bpf/verifier.c in the Linux kernel through 4.14.8 ignores unreachable code, even though it would still be processed by JIT compilers. This behavior, also considered an improper branch-pruning logic issue, could possibly be used by local users for denial of service.



This bug was filed by http://go/vomit
Please contact us at vomit-team@google.com if you need any assistance.

 

Comment 1 by groeck@chromium.org, Jan 10 2018

Cc: wonderfly@google.com
Labels: Security_Severity-Low Security_Impact-None M-65 Pri-2
Owner: groeck@chromium.org
Status: ExternalDependency (was: Untriaged)
Upstream c131187db2d3fa2f8bf32fdf4e9a4ef805168467 ("Subject: bpf: fix branch pruning logic").

Only affects system with BPF_SYSCALL enabled, which is not the case with ChromeOS. Will apply fix into chromeos-4.4 and chromeos-4.14 through stable release merges.

Comment 2 by groeck@chromium.org, Jan 10 2018

Status: WontFix (was: ExternalDependency)
Already fixed in both chromeos-4.4 and chromeos-4.14 with stable release merges.

Cc: sawlani@google.com

Comment 4 by sawlani@google.com, Jan 10 2018

@groeck can you paste commit for 4.4? I'm not able to locate in 4.4 stable-tree.

Comment 5 by groeck@chromium.org, Jan 11 2018

Status: Assigned (was: WontFix)
#4: Thanks for having another look. I messed that one up. No idea where I got the idea from that it is fixed in 4.4.

Comment 6 by groeck@chromium.org, Jan 11 2018

Problem with 4.4 may be that this doesn't apply; the code changes are too substantial. We would have to effectively re-implement the code. We'll need to discuss if this is worth it given the low severity of the problem.


Comment 7 by groeck@chromium.org, Jan 11 2018

Status: WontFix (was: Assigned)
Per the description in commit c131187db2d3fa2f8bf3, this only creates a problem if BPF_JIT is enabled. However, BPF_JIT is not enabled in Chrome OS or Lakitu. Given that, due to the complexity of fixing the problem (assuming it applies) in chromeos-4.4, and since this is a low severity bug, marking it as WontFix again.

Comment 8 by sawlani@google.com, Jan 11 2018

Great! No need to backport.

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