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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:  1033563
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
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-2015:1787-01] 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-2015:1787-01
Product:           Red Hat Enterprise MRG for RHEL-6
Advisory URL:
Issue date:        2015-09-15
CVE Names:         CVE-2014-9585 CVE-2015-0275 CVE-2015-1333 
                   CVE-2015-3212 CVE-2015-5364 CVE-2015-5366 

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:

MRG Realtime for RHEL 6 Server v.2 - noarch, x86_64

3. Description:

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

* 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 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

This update provides a build of the kernel-rt package for Red Hat
Enterprise MRG 2.5 that is layered on Red Hat Enterprise Linux 6, and fixes
the following issues:

* Fix regression in scsi_send_eh_cmnd()

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

* Update tcp stack to 3.17 kernel

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


This update also fixes the following bugs:

* The configuration option CONFIG_RTC_HCTOSYS was disabled on the realtime
kernel causing the RTC clock to be adjusted with the UTC time even if the
system is configured to set the RTC to the local time. By enabling the
CONFIG_RTC_HCTOSYS configuration option, when the system is configured to
use local time, RTC will correctly update with the local time and not try
to use another timezone. (BZ#1248047)

* In the realtime kernel, if a rt_mutex was taken while in interrupt
context the normal priority inheritance protocol would falsely identify a
deadlock and trigger a kernel crash. The patch that added the rt_mutex in
this interrupt context was reverted. (BZ#1250649)

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
1239029 - CVE-2015-5366 CVE-2015-5364 kernel: net: incorrect processing of checksums in UDP implementation
1245345 - RFE: update the MRG 2.5 3.10 kernel-rt sources
1245658 - CVE-2015-1333 kernel: denial of service due to memory leak in add_key()

6. Package List:

MRG Realtime for RHEL 6 Server v.2:




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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