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T-700:Red Hat: kernel security, bug fix, and enhancement update

August 24, 2011 - 3:45pm

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PROBLEM:

Updated kernel packages that fix several security issues, various bugs, and add two enhancements are now available for Red Hat Enterprise Linux 6.

PLATFORM:

Red Hat Enterprise Linux Desktop (v. 6)
Red Hat Enterprise Linux HPC Node (v. 6)
Red Hat Enterprise Linux Server (v. 6)
Red Hat Enterprise Linux Server EUS (v. 6.1.z)
Red Hat Enterprise Linux Workstation (v. 6)

ABSTRACT:

Red Hat: kernel security, bug fix, and enhancement update.

reference LINKS:

RHSA-2011: 1189-1
Secunia Advisory: SA45746
Red Hat Download
CVE-2011-1182 , CVE-2011-1576
CVE-2011-1593 , CVE-2011-1776
CVE-2011-1898 , CVE-2011-2183
CVE-2011-2213 , CVE-2011-2491
CVE-2011-2492 , CVE-2011-2495
CVE-2011-2497 , CVE-2011-2517
CVE-2011-2689 , CVE-2011-2695

IMPACT ASSESSMENT:

High

Discussion:

* Using PCI passthrough without interrupt remapping support allowed KVM guests to generate MSI interrupts and thus potentially inject traps. A privileged guest user could use this flaw to crash the host or possibly escalate their privileges on the host.
The fix for this issue can prevent PCI passthrough working and guests starting. Refer to Red Hat Bugzilla bug 715555 for details. (CVE-2011-1898, Important)
* Flaw in the client-side NLM implementation could allow a local, unprivileged user to cause a denial of service. (CVE-2011-2491, Important)
* Integer underflow in the Bluetooth implementation could allow a remote attacker to cause a denial of service or escalate their privileges by sending a specially-crafted request to a target system via Bluetooth. (CVE-2011-2497, Important)
* Buffer overflows in the netlink-based wireless configuration interface implementation could allow a local user, who has the CAP_NET_ADMIN capability, to cause a denial of service or escalate their privileges on systems that have an active wireless interface. (CVE-2011-2517, Important)
* Flaw in the way the maximum file offset was handled for ext4 file systems could allow a local, unprivileged user to cause a denial of service. (CVE-2011-2695, Important)
* Flaw allowed napi_reuse_skb() to be called on VLAN packets. An attacker on the local network could use this flaw to send crafted packets to a target, possibly causing a denial of service. (CVE-2011-1576, Moderate)
* Integer signedness error in next_pidmap() could allow a local, unprivileged user to cause a denial of service. (CVE-2011-1593, Moderate)
* Race condition in the memory merging support (KSM) could allow a local, unprivileged user to cause a denial of service. KSM is off by default, but on systems running VDSM, or on KVM hosts, it is likely turned on by the ksm/ksmtuned services. (CVE-2011-2183, Moderate)
* Flaw in inet_diag_bc_audit() could allow a local, unprivileged user to cause a denial of service. (CVE-2011-2213, Moderate)
* Flaw in the way space was allocated in the Global File System 2 (GFS2) implementation. If the file system was almost full, and a local, unprivileged user made an fallocate() request, it could result in a denial of service.
Setting quotas to prevent users from using all available disk space would prevent exploitation of this flaw. (CVE-2011-2689, Moderate)
* Local, unprivileged users could send signals via the sigqueueinfo system call, with si_code set to SI_TKILL and with spoofed process and user IDs, to other processes. This flaw does not allow existing permission checks to be bypassed; signals can only be sent if your privileges allow you to already do so. (CVE-2011-1182, Low)
* Heap overflow in the EFI GUID Partition Table (GPT) implementation could allow a local attacker to cause a denial of service by mounting a disk containing crafted partition tables. (CVE-2011-1776, Low)
* Structure padding in two structures in the Bluetooth implementation was not initialized properly before being copied to user-space, possibly allowing local, unprivileged users to leak kernel stack memory to user-space. (CVE-2011-2492, Low)
* /proc/[PID]/io is world-readable by default. Previously, these files could be read without any further restrictions. A local, unprivileged user could read these files, belonging to other, possibly privileged processes to gather confidential information, such as the length of a password used in a process. (CVE-2011-2495, Low)

Impact:

Bug 690028 - CVE-2011-1182 kernel signal spoofing issue
Bug 695173 - CVE-2011-1576 kernel: net: Fix memory leak/corruption on VLAN GRO_DROP
Bug 697822 - CVE-2011-1593 kernel: proc: signedness issue in next_pidmap()
Bug 703019 - CVE-2011-2492 kernel: bluetooth: l2cap and rfcomm: fix 1 byte infoleak to userspace
Bug 703026 - CVE-2011-1776 kernel: validate size of EFI GUID partition entries
Bug 709393 - CVE-2011-2491 kernel: rpc task leak after flock()ing NFS share
Bug 710338 - CVE-2011-2183 kernel: ksm: race between ksmd and exiting task
Bug 713827 - Parallel port issue in RHEL 6.0 server
Bug 714536 - CVE-2011-2213 kernel: inet_diag: insufficient validation
Bug 714982 - GFS2: Update to rhel6.1 broke dovecot writing to a gfs2 filesystem
Bug 715555 - CVE-2011-1898 virt: VT-d (PCI passthrough) MSI trap injection
Bug 716539 - bump domain memory limits [6.1.z]
Bug 716805 - CVE-2011-2497 kernel: bluetooth: buffer overflow in l2cap config request
Bug 716825 - CVE-2011-2495 kernel: /proc/PID/io infoleak
Bug 718152 - CVE-2011-2517 kernel: nl80211: missing check for valid SSID size in scan operations
Bug 720861 - CVE-2011-2689 kernel: gfs2: make sure fallocate bytes is a multiple of blksize
Bug 722557 - CVE-2011-2695 kernel: ext4: kernel panic when writing data to the last block of sparse file

Solution:

Red Hat has issued an update for the kernel. This fixes multiple vulnerabilities, which can be exploited by malicious, local users to disclose certain system information, bypass certain security restrictions, cause a DoS (Denial of Service) and by malicious people to potentially compromise a vulnerable system.
Administrator should upgrade to these updated packages, which contain backported patches to correct these issues, and fix the bugs and add the enhancements noted in the Technical Notes. The system must be rebooted for this update to take effect.
To install kernel packages manually, use "rpm -ivh [package]". Do not use "rpm -Uvh" as that will remove the running kernel binaries from your system. You may use "rpm -e" to remove old kernels after determining that the new kernel functions properly on your system.
Red Hat Support
 

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