7.2 - RHSA-2012:0743

Problem Description:

Updated kernel packages that fix multiple security issues and several bugs are now available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team 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 Desktop (v. 6) - i386, noarch, x86_64 Red Hat Enterprise Linux Desktop Optional (v. 6) - i386, x86_64 Red Hat Enterprise Linux HPC Node (v. 6) - noarch, x86_64 Red Hat Enterprise Linux HPC Node Optional (v. 6) - x86_64 Red Hat Enterprise Linux Server (v. 6) - i386, noarch, ppc64, s390x, x86_64 Red Hat Enterprise Linux Server Optional (v. 6) - i386, ppc64, s390x, x86_64 Red Hat Enterprise Linux Workstation (v. 6) - i386, noarch, x86_64 Red Hat Enterprise Linux Workstation Optional (v. 6) - i386, x86_64

3. Description:

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

This update fixes the following security issues:

* A local, unprivileged user could use an integer overflow flaw in drm_mode_dirtyfb_ioctl() to cause a denial of service or escalate their privileges. (CVE-2012-0044, Important)

* A buffer overflow flaw was found in the macvtap device driver, used for creating a bridged network between the guest and the host in KVM (Kernel-based Virtual Machine) environments. A privileged guest user in a KVM guest could use this flaw to crash the host. Note: This issue only affected hosts that have the vhost_net module loaded with the experimental_zcopytx module option enabled (it is not enabled by default), and that also have macvtap configured for at least one guest. (CVE-2012-2119, Important)

* When a set user ID (setuid) application is executed, certain personality flags for controlling the application's behavior are cleared (that is, a privileged application will not be affected by those flags). It was found that those flags were not cleared if the application was made privileged via file system capabilities. A local, unprivileged user could use this flaw to change the behavior of such applications, allowing them to bypass intended restrictions. Note that for default installations, no application shipped by Red Hat for Red Hat Enterprise Linux is made privileged via file system capabilities. (CVE-2012-2123, Important)

* It was found that the data_len parameter of the sock_alloc_send_pskb() function in the Linux kernel's networking implementation was not validated before use. A privileged guest user in a KVM guest could use this flaw to crash the host or, possibly, escalate their privileges on the host. (CVE-2012-2136, Important)

* A buffer overflow flaw was found in the setup_routing_entry() function in the KVM subsystem of the Linux kernel in the way the Message Signaled Interrupts (MSI) routing entry was handled. A local, unprivileged user could use this flaw to cause a denial of service or, possibly, escalate their privileges. (CVE-2012-2137, Important)

* A race condition was found in the Linux kernel's memory management subsystem in the way pmd_none_or_clear_bad(), when called with mmap_sem in read mode, and Transparent Huge Pages (THP) page faults interacted. A privileged user in a KVM guest with the ballooning functionality enabled could potentially use this flaw to crash the host. A local, unprivileged user could use this flaw to crash the system. (CVE-2012-1179, Moderate)

* A flaw was found in the way device memory was handled during guest device removal. Upon successful device removal, memory used by the device was not properly unmapped from the corresponding IOMMU or properly released from the kernel, leading to a memory leak. A malicious user on a KVM host who has the ability to assign a device to a guest could use this flaw to crash the host. (CVE-2012-2121, Moderate)

* A flaw was found in the Linux kernel's Reliable Datagram Sockets (RDS) protocol implementation. A local, unprivileged user could use this flaw to cause a denial of service. (CVE-2012-2372, Moderate)

* A race condition was found in the Linux kernel's memory management subsystem in the way pmd_populate() and pte_offset_map_lock() interacted on 32-bit x86 systems with more than 4GB of RAM. A local, unprivileged user could use this flaw to cause a denial of service. (CVE-2012-2373, Moderate)

Red Hat would like to thank Chen Haogang for reporting CVE-2012-0044.

This update also fixes several bugs. Documentation for these changes will be available shortly from the Technical Notes document linked to in the References section.

Users should upgrade to these updated packages, which contain backported patches to correct these issues, and fix the bugs noted in the Technical Notes. 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.

This update is available via the Red Hat Network. Details on how to use the Red Hat Network to apply this update are available at https://access.redhat.com/knowledge/articles/11258

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.

5. Bugs fixed (http://bugzilla.redhat.com/):

772894 - CVE-2012-0044 kernel: drm: integer overflow in drm_mode_dirtyfb_ioctl() 803793 - CVE-2012-1179 kernel: thp:__split_huge_page() mapcount != page_mapcount BUG_ON() 806722 - CVE-2012-2123 kernel: fcaps: clear the same personality flags as suid when fcaps are used 814149 - CVE-2012-2121 kvm: device assignment page leak 814278 - CVE-2012-2119 kernel: macvtap: zerocopy: vector length is not validated before pinning user pages 814657 - kernel crash at ieee80211_mgd_probe_ap_send [rhel-6.2.z] 816151 - CVE-2012-2137 kernel: kvm: buffer overflow in kvm_set_irq() 816226 - add option to disable 5GHz band to iwlwifi [rhel-6.2.z] 816289 - CVE-2012-2136 kernel: net: insufficient data_len validation in sock_alloc_send_pskb() 818504 - Disable LRO for all NICs that have LRO enabled [rhel-6.2.z] 818505 - xen: fix drive naming [rhel-6.2.z] 819614 - 2.6.32-220 kernel does not work on a HP DL385G6 with HP Smart Array P410 controller and hpsa driver [rhel-6.2.z] 822754 - CVE-2012-2372 kernel: rds-ping cause kernel panic 822821 - CVE-2012-2373 kernel: mm: read_pmd_atomic: 32bit PAE pmd walk vs pmd_populate SMP race condition