Topic

An update for kernel is now available for Red Hat Enterprise Linux 7.4 Extended Update Support.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

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

Security Fix(es):

• A flaw was found in the implementation of the "fill buffer", a mechanism used by modern CPUs when a cache-miss is made on L1 CPU cache. If an attacker can generate a load operation that would create a page fault, the execution will continue speculatively with incorrect data from the fill buffer while the data is fetched from higher level caches. This response time can be measured to infer data in the fill buffer. (CVE-2018-12130)
• Modern Intel microprocessors implement hardware-level micro-optimizations to improve the performance of writing data back to CPU caches. The write operation is split into STA (STore Address) and STD (STore Data) sub-operations. These sub-operations allow the processor to hand-off address generation logic into these sub-operations for optimized writes. Both of these sub-operations write to a shared distributed processor structure called the 'processor store buffer'. As a result, an unprivileged attacker could use this flaw to read private data resident within the CPU's processor store buffer. (CVE-2018-12126)
• Microprocessors use a ‘load port’ subcomponent to perform load operations from memory or IO. During a load operation, the load port receives data from the memory or IO subsystem and then provides the data to the CPU registers and operations in the CPU’s pipelines. Stale load operations results are stored in the 'load port' table until overwritten by newer operations. Certain load-port operations triggered by an attacker can be used to reveal data about previous stale requests leaking data back to the attacker via a timing side-channel. (CVE-2018-12127)
• Uncacheable memory on some microprocessors utilizing speculative execution may allow an authenticated user to potentially enable information disclosure via a side channel with local access. (CVE-2019-11091)
• kernel: Buffer overflow in firewire driver via crafted incoming packets (CVE-2016-8633)
• kernel: crypto: privilege escalation in skcipher_recvmsg function (CVE-2017-13215)
• Kernel: ipsec: xfrm: use-after-free leading to potential privilege escalation (CVE-2017-16939)
• kernel: Out-of-bounds write via userland offsets in ebt_entry struct in netfilter/ebtables.c (CVE-2018-1068)
• kernel: Use-after-free due to race condition in AF_PACKET implementation (CVE-2018-18559)
• kernel: media: use-after-free in [tuner-xc2028] media driver (CVE-2016-7913)
• kernel: Out-of-bounds access via an XFRM_MSG_MIGRATE xfrm Netlink message (CVE-2017-11600)
• kernel: memory leak when merging buffers in SCSI IO vectors (CVE-2017-12190)
• kernel: Unallocated memory access by malicious USB device via bNumInterfaces overflow (CVE-2017-17558)
• Kernel: KVM: DoS via write flood to I/O port 0x80 (CVE-2017-1000407)
• Kernel: FPU state information leakage via lazy FPU restore (CVE-2018-3665)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Bug Fix(es):

• rwsem in inconsistent state leading system to hung (BZ#1690321)
• efi_bgrt_init fails to ioremap error during boot (BZ#1692284)

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.

Affected Products

• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.4 x86_64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.4 ppc64
• Red Hat Enterprise Linux EUS Compute Node 7.4 x86_64
• Red Hat Enterprise Linux Server - AUS 7.4 x86_64
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.4 s390x
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.4 ppc64le
• Red Hat Enterprise Linux Server - TUS 7.4 x86_64
• Red Hat Enterprise Linux Server (for IBM Power LE) - Update Services for SAP Solutions 7.4 ppc64le
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.4 x86_64

Fixes

• BZ - 1391490 - CVE-2016-8633 kernel: Buffer overflow in firewire driver via crafted incoming packets
• BZ - 1402885 - CVE-2016-7913 kernel: media: use-after-free in [tuner-xc2028] media driver
• BZ - 1474928 - CVE-2017-11600 kernel: Out-of-bounds access via an XFRM_MSG_MIGRATE xfrm Netlink message
• BZ - 1495089 - CVE-2017-12190 kernel: memory leak when merging buffers in SCSI IO vectors
• BZ - 1517220 - CVE-2017-16939 Kernel: ipsec: xfrm: use-after-free leading to potential privilege escalation
• BZ - 1520328 - CVE-2017-1000407 Kernel: KVM: DoS via write flood to I/O port 0x80
• BZ - 1525474 - CVE-2017-17558 kernel: Unallocated memory access by malicious USB device via bNumInterfaces overflow
• BZ - 1535173 - CVE-2017-13215 kernel: crypto: privilege escalation in skcipher_recvmsg function
• BZ - 1552048 - CVE-2018-1068 kernel: Out-of-bounds write via userland offsets in ebt_entry struct in netfilter/ebtables.c
• BZ - 1585011 - CVE-2018-3665 Kernel: FPU state information leakage via lazy FPU restore
• BZ - 1641878 - CVE-2018-18559 kernel: Use-after-free due to race condition in AF_PACKET implementation
• BZ - 1646781 - CVE-2018-12126 hardware: Microarchitectural Store Buffer Data Sampling (MSBDS)
• BZ - 1646784 - CVE-2018-12130 hardware: Microarchitectural Fill Buffer Data Sampling (MFBDS)
• BZ - 1667782 - CVE-2018-12127 hardware: Micro-architectural Load Port Data Sampling - Information Leak (MLPDS)
• BZ - 1705312 - CVE-2019-11091 hardware: Microarchitectural Data Sampling Uncacheable Memory (MDSUM)

CVEs

• CVE-2016-7913
• CVE-2016-8633
• CVE-2017-11600
• CVE-2017-12190
• CVE-2017-13215
• CVE-2017-16939
• CVE-2017-17558
• CVE-2017-1000407
• CVE-2018-1068
• CVE-2018-3665
• CVE-2018-12126
• CVE-2018-12127
• CVE-2018-12130
• CVE-2018-18559
• CVE-2019-11091

References

• https://access.redhat.com/security/updates/classification/#important
• https://access.redhat.com/security/vulnerabilities/mds