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Bug 1525761 (CVE-2017-17450)

Summary: CVE-2017-17450 kernel: Unchecked capabilities in net/netfilter/xt_osf.c allows for unprivileged modification to systemwide fingerprint list
Product: [Other] Security Response Reporter: Sam Fowler <sfowler>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED WONTFIX QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: agordeev, airlied, ajax, aquini, bhu, blc, bskeggs, dhoward, ewk, fhrbata, hdegoede, hkrzesin, hwkernel-mgr, ichavero, itamar, jarodwilson, jeremy, jforbes, jglisse, jkacur, john.j5live, jonathan, josef, jwboyer, kernel-maint, kernel-mgr, labbott, lgoncalv, linville, lwang, mchehab, mguzik, mjg59, mlangsdo, nmurray, plougher, rvrbovsk, skozina, slawomir, steved, vdronov, williams
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
net/netfilter/xt_osf.c in the Linux kernel through 4.14.4 does not require the CAP_NET_ADMIN capability for add_callback and remove_callback operations. This allows local users to bypass intended access restrictions because the xt_osf_fingers data structure is shared across all network namespaces.
Story Points: ---
Clone Of: Environment:
Last Closed: 2018-01-25 10:30:55 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1525764    
Bug Blocks:    

Description Sam Fowler 2017-12-14 01:25:57 UTC
net/netfilter/xt_osf.c in the Linux kernel through 4.14.4 does not require the CAP_NET_ADMIN capability for add_callback and remove_callback operations, which allows local users to bypass intended access restrictions because the xt_osf_fingers data structure is shared across all network namespaces.

References:

https://lkml.org/lkml/2017/12/5/982

https://marc.info/?t=151251761200002&r=1&w=2

An upstream patch:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=916a27901de01446bcf57ecca4783f6cff493309

Comment 1 Sam Fowler 2017-12-14 01:48:42 UTC
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1525764]

Comment 4 Vladis Dronov 2018-01-24 16:38:40 UTC
Statement:

This issue does not affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 5 and Red Hat Enterprise MRG 2, as a code with the flaw is not present or is not built in the products listed.

This issue affects the versions of the Linux kernel as shipped with Red Hat Enterprise Linux 6, 7, its real-time kernel, Red Hat Enterprise Linux 7 for ARM 64 and Red Hat Enterprise Linux 7 for Power 9 LE. This has been rated as having Low security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.

Comment 5 Vladis Dronov 2018-01-24 16:39:25 UTC
What is Red Hat Enterprise Linux 7 for ARM 64,
        Red Hat Enterprise Linux 7 for Power 9 LE

The kernel package as shipped with Red Hat Enterprise Linux 7 for ARM 64 and Red Hat Enterprise Linux 7 for Power 9 LE is an updated kernel intended to support new architectures not available at the time of Red Hat Enterprise Linux 7 original shipping. The new kernel version is based on an upstream Linux kernel version 4.11. The offering is distributed with other updated packages, but most of the userspace is the standard Red Hat Enterprise Linux 7 Server RPM files.

For more information please refer to:

https://access.redhat.com/articles/3158541
https://access.redhat.com/articles/3158511