RHSA-2017:1491: Important: kernel security and bug fix update
The kernel packages contain the Linux kernel, the core of any Linux operating system.Security Fix(es): A flaw was found in the way memory was being allocated on the stack for user space binaries. If heap (or different memory region) and stack memory regions were adjacent to each other, an attacker could use this flaw to jump over the stack guard gap, cause controlled memory corruption on process stack or the adjacent memory region, and thus increase their privileges on the system. This is a kernel-side mitigation which increases the stack guard gap size from one page to 1 MiB to make successful exploitation of this issue more difficult. (CVE-2017-1000364, Important) Red Hat would like to thank Qualys Research Labs for reporting this issue.Bug Fix(es): Previously, a kernel panic occurred when the mcelog daemon executed a huge page memory offline. This update fixes the HugeTLB feature of the Linux kernel to check for the Page Table Entry (PTE) NULL pointer in the pagecheckaddress() function. As a result, the kernel panic no longer occurs under the described circumstances. (BZ#1444342) Previously, the kdump mechanism was trying to get the lock by the vmallocsyncall() function during a kernel panic. Consequently, a deadlock occurred, and the crashkernel did not boot. This update fixes the vmallocsyncall() function to avoid synchronizing the vmalloc area on the crashing CPU. As a result, the crashkernel parameter now boots as expected, and the kernel dump is collected successfully under the described circumstances. (BZ#1443494)
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-debugto a version that resolves this vulnerability.Fixed in 2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-debug-debuginfoto a version that resolves this vulnerability.Fixed in 2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-debug-develto a version that resolves this vulnerability.Fixed in 2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-debuginfoto a version that resolves this vulnerability.Fixed in 2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-develto a version that resolves this vulnerability.Fixed in 2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-docto a version that resolves this vulnerability.Fixed in 2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-firmwareto a version that resolves this vulnerability.Fixed in 2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-headersto a version that resolves this vulnerability.Fixed in 2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/perfto a version that resolves this vulnerability.Fixed in 2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/perf-debuginfoto a version that resolves this vulnerability.Fixed in 2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/python-perfto a version that resolves this vulnerability.Fixed in 2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/python-perf-debuginfoto a version that resolves this vulnerability.Fixed in 2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 0:2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-debugto a version that resolves this vulnerability.Fixed in 0:2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-debug-debuginfoto a version that resolves this vulnerability.Fixed in 0:2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-debug-develto a version that resolves this vulnerability.Fixed in 0:2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-debuginfoto a version that resolves this vulnerability.Fixed in 0:2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-debuginfo-common-x86_64to a version that resolves this vulnerability.Fixed in 0:2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-develto a version that resolves this vulnerability.Fixed in 0:2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-docto a version that resolves this vulnerability.Fixed in 0:2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-firmwareto a version that resolves this vulnerability.Fixed in 0:2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/kernel-headersto a version that resolves this vulnerability.Fixed in 0:2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/perfto a version that resolves this vulnerability.Fixed in 0:2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/perf-debuginfoto a version that resolves this vulnerability.Fixed in 0:2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/python-perf-debuginfoto a version that resolves this vulnerability.Fixed in 0:2.6.32-220.72.2.el6 - Upgrade
Upgrade
redhat/python-perfto a version that resolves this vulnerability.Fixed in 0:2.6.32-220.72.2.el6 - Compensating control
Use the kernel-side mitigation that increases the stack guard gap from one page to 1 MiB, making successful exploitation more difficult.
- Operational
Reboot the system for the update to take effect.
Event History
Frequently Asked Questions
What is the severity of RHSA-2017:1491?
The severity of RHSA-2017:1491 is classified as Important.
How do I fix RHSA-2017:1491?
To fix RHSA-2017:1491, you should update the kernel packages to version 2.6.32-220.72.2.el6 or later.
What systems are affected by RHSA-2017:1491?
RHSA-2017:1491 affects Red Hat Enterprise Linux 6 with specific kernel versions.
What is the nature of the vulnerability in RHSA-2017:1491?
The vulnerability in RHSA-2017:1491 involves improper memory allocation on the stack for user space binaries.
What are the possible consequences of not addressing RHSA-2017:1491?
Failing to address RHSA-2017:1491 could lead to potential exploit vulnerabilities that may compromise system integrity.