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Bug 1552048 - (CVE-2018-1068) CVE-2018-1068 kernel: Out-of-bounds write via userland offsets in ebt_entry struct in netfilter/ebtables.c
CVE-2018-1068 kernel: Out-of-bounds write via userland offsets in ebt_entry s...
Status: NEW
Product: Security Response
Classification: Other
Component: vulnerability (Show other bugs)
unspecified
All Linux
high Severity high
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Assigned To: Red Hat Product Security
impact=important,public=20180305,repo...
: Security
Depends On: 1552369 1552364 1552365 1552366 1552367 1552368 1552370 1557238 1557239
Blocks: 1551689
  Show dependency treegraph
 
Reported: 2018-03-06 07:06 EST by Pedro Sampaio
Modified: 2018-10-30 04:59 EDT (History)
48 users (show)

See Also:
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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Attachments (Terms of Use)


External Trackers
Tracker ID Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2018:1318 None None None 2018-05-08 14:25 EDT
Red Hat Product Errata RHSA-2018:1355 None None None 2018-05-08 18:24 EDT
Red Hat Product Errata RHSA-2018:2948 None None None 2018-10-30 04:59 EDT

  None (edit)
Description Pedro Sampaio 2018-03-06 07:06:52 EST
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 07:50:03 EDT
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 05:34:20 EDT
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1557238]
Comment 7 Fedora Update System 2018-03-20 13:36:10 EDT
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 14:25:18 EDT
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 18:24:25 EDT
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 04:58:47 EDT
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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