Bug 1552048 (CVE-2018-1068) - CVE-2018-1068 kernel: Out-of-bounds write via userland offsets in ebt_entry struct in netfilter/ebtables.c
Summary: CVE-2018-1068 kernel: Out-of-bounds write via userland offsets in ebt_entry s...
Status: NEW
Alias: CVE-2018-1068
Product: Security Response
Classification: Other
Component: vulnerability   
(Show other bugs)
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard: impact=important,public=20180305,repo...
Keywords: Security
Depends On: 1552369 1552364 1552365 1552366 1552367 1552368 1552370 1557238 1557239
Blocks: 1551689
TreeView+ depends on / blocked
 
Reported: 2018-03-06 12:06 UTC by Pedro Sampaio
Modified: 2019-02-08 15:03 UTC (History)
47 users (show)

Fixed In Version: kernel-3.10.0-862.1.1.el7
Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in the Linux kernel's implementation of 32-bit syscall interface for bridging. This allowed a privileged user to arbitrarily write to a limited range of kernel memory.
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RHEL 7.3 requirements from Atomic Host:
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External Trackers
Tracker ID Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2018:1318 None None None 2018-05-08 18:25 UTC
Red Hat Product Errata RHSA-2018:1355 None None None 2018-05-08 22:24 UTC
Red Hat Product Errata RHSA-2018:2948 None None None 2018-10-30 08:59 UTC

Description Pedro Sampaio 2018-03-06 12:06:52 UTC
A flaw was found in the latest Linux kernel. A out-of-bounds write of kernel address space may be triggered via uncontrolled userland provided offset in ebt_entry struct in netfilter/ebtables.c.

References:

https://marc.info/?l=linux-netdev&m=152023808817590&w=2

https://marc.info/?l=linux-netdev&m=152025888924151&w=2

An upsteam patch:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b71812168571fa55e44cdd0254471331b9c4c4c6

https://github.com/torvalds/linux/commit/b71812168571fa55e44cdd0254471331b9c4c4c6

Comment 4 Vladis Dronov 2018-03-13 11:50:03 UTC
Notes:

The related permission check in the kernel code is as follows:

[ net/bridge/netfilter/ebtables.c ]
static int compat_do_ebt_set_ctl(struct sock *sk, ...
{
        ...
        if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
                return -EPERM;

This mean that this flaw can be exploited not only by a system's privileged user (a real "root" user), but also by an attacker who is a privileged user (a "root" user) in a user+network namespace, for example, on some container hosting. So, the impact of this flaw is rated as Important.

Comment 5 Vladis Dronov 2018-03-16 09:34:20 UTC
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1557238]

Comment 7 Fedora Update System 2018-03-20 17:36:10 UTC
kernel-4.15.10-200.fc26 has been pushed to the Fedora 26 stable repository. If problems still persist, please make note of it in this bug report.

Comment 8 errata-xmlrpc 2018-05-08 18:25:18 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2018:1318 https://access.redhat.com/errata/RHSA-2018:1318

Comment 9 errata-xmlrpc 2018-05-08 22:24:25 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2018:1355 https://access.redhat.com/errata/RHSA-2018:1355

Comment 10 errata-xmlrpc 2018-10-30 08:58:47 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2018:2948 https://access.redhat.com/errata/RHSA-2018:2948


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