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Category:   OS (Linux)  >   Linux Kernel Vendors:
(Red Hat Issues Fix) Linux Kernel UDP Processing Flaw Lets Remote Users Deny Service
SecurityTracker Alert ID:  1033567
SecurityTracker URL:
CVE Reference:   CVE-2015-5364, CVE-2015-5366   (Links to External Site)
Date:  Sep 16 2015
Impact:   Denial of service via network
Fix Available:  Yes  Vendor Confirmed:  Yes  
Version(s): RHEL 7 (Realtime)
Description:   Two vulnerabilities were reported in the Linux Kernel. A remote user can cause denial of service conditions on the target system.

A remote user can send a flood of UDP packets with specially crafted checksums to cause the target application to hang [CVE-2015-5364].

A remote user can send a flood of UDP packets with specially crafted checksums to cause the target application to stop reading packets [CVE-2015-5366].

Impact:   A remote user can cause the target application to hang.

A remote user can cause the target application to stop reading packets.

Solution:   Red Hat has issued a fix.

The Red Hat advisory is available at:

Vendor URL: (Links to External Site)
Cause:   State error

Message History:   This archive entry is a follow-up to the message listed below.
Jul 7 2015 Linux Kernel UDP Processing Flaw Lets Remote Users Deny Service

 Source Message Contents

Subject:  [RHSA-2015:1788-01] Important: kernel-rt security, bug fix, and enhancement update

Hash: SHA1

                   Red Hat Security Advisory

Synopsis:          Important: kernel-rt security, bug fix, and enhancement update
Advisory ID:       RHSA-2015:1788-01
Product:           Red Hat Enterprise Linux
Advisory URL:
Issue date:        2015-08-12
Updated on:        2015-09-15
CVE Names:         CVE-2014-9585 CVE-2015-0275 CVE-2015-1333 
                   CVE-2015-3212 CVE-2015-4700 CVE-2015-5364 

1. Summary:

Updated kernel-rt packages that fix multiple security issues, several bugs,
and add various enhancements are now available for Red Hat Enterprise
Linux 7.

Red Hat Product Security has rated this update as having Important security
impact. Common Vulnerability Scoring System (CVSS) base scores, which give
detailed severity ratings, are available for each vulnerability from the
CVE links in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Realtime (v. 7) - noarch, x86_64

3. Description:

The kernel-rt packages contain the Linux kernel, the core of any Linux
operating system.

* A flaw was found in the kernel's implementation of the Berkeley Packet
Filter (BPF). A local attacker could craft BPF code to crash the system by
creating a situation in which the JIT compiler would fail to correctly
optimize the JIT image on the last pass. This would lead to the CPU
executing instructions that were not part of the JIT code. (CVE-2015-4700,

* Two flaws were found in the way the Linux kernel's networking
implementation handled UDP packets with incorrect checksum values. A remote
attacker could potentially use these flaws to trigger an infinite loop in
the kernel, resulting in a denial of service on the system, or cause a
denial of service in applications using the edge triggered epoll
functionality. (CVE-2015-5364, CVE-2015-5366, Important)

* A flaw was found in the way the Linux kernel's ext4 file system handled
the "page size > block size" condition when the fallocate zero range
functionality was used. A local attacker could use this flaw to crash the
system. (CVE-2015-0275, Moderate)

* It was found that the Linux kernel's keyring implementation would leak
memory when adding a key to a keyring via the add_key() function. A local
attacker could use this flaw to exhaust all available memory on the system.
(CVE-2015-1333, Moderate)

* A race condition flaw was found in the way the Linux kernel's SCTP
implementation handled Address Configuration lists when performing Address
Configuration Change (ASCONF). A local attacker could use this flaw to
crash the system via a race condition triggered by setting certain ASCONF
options on a socket. (CVE-2015-3212, Moderate)

* An information leak flaw was found in the way the Linux kernel's Virtual
Dynamic Shared Object (vDSO) implementation performed address
randomization. A local, unprivileged user could use this flaw to leak
kernel memory addresses to user-space. (CVE-2014-9585, Low)

Red Hat would like to thank Daniel Borkmann for reporting CVE-2015-4700,
and Canonical for reporting the CVE-2015-1333 issue. The CVE-2015-0275
issue was discovered by Xiong Zhou of Red Hat, and the CVE-2015-3212 issue
was discovered by Ji Jianwen of Red Hat Engineering.

The kernel-rt packages have been upgraded to version 3.10.0-229.13.1, which
provides a number of bug fixes and enhancements over the previous version,

* Fix regression in scsi_send_eh_cmnd()

* boot hangs at "Console: switching to colour dummy device 80x25"

* Update tcp stack to 3.17 kernel

* Missing some code from patch "(...) Fix VGA switcheroo problem related to

* ksoftirqd high CPU usage due to stray tasklet from ioatdma driver

* During Live Partition Mobility (LPM) testing, RHEL 7.1 LPARs will crash
in kmem_cache_alloc


This update also fixes the following bug:

* The hwlat_detector.ko module samples the clock and records any intervals
between reads that exceed a specified threshold. However, the module
previously tracked the maximum interval seen for the "inner" interval but
did not record when the "outer" interval was greater. A patch has been
applied to fix this bug, and hwlat_detector.ko now correctly records if the
outer interval is the maximal interval encountered during the run.

All kernel-rt users are advised to upgrade to these updated packages, which
correct these issues and add these enhancements. The system must be
rebooted for this update to take effect.

4. Solution:

Before applying this update, make sure all previously released errata
relevant to your system have been applied.

For details on how to apply this update, refer to:

5. Bugs fixed (

1181054 - CVE-2014-9585 kernel: ASLR bruteforce possible for vdso library
1193907 - CVE-2015-0275 kernel: fs: ext4: fallocate zero range page size > block size BUG()
1226442 - CVE-2015-3212 kernel: SCTP race condition allows list corruption and panic from userlevel
1233615 - CVE-2015-4700 kernel: Crafted BPF filters may crash kernel during JIT optimisation
1239029 - CVE-2015-5366 CVE-2015-5364 kernel: net: incorrect processing of checksums in UDP implementation
1245658 - CVE-2015-1333 kernel: denial of service due to memory leak in add_key()
1253809 - kernel-rt: update to the RHEL7.1.z batch 5 source tree

6. Package List:

Red Hat Enterprise Linux Realtime (v. 7):




These packages are GPG signed by Red Hat for security.  Our key and
details on how to verify the signature are available from

7. References:

8. Contact:

The Red Hat security contact is <>. More contact
details at

Copyright 2015 Red Hat, Inc.
Version: GnuPG v1


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