-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 ==================================================================== Red Hat Security Advisory Synopsis: Important: kernel-rt security and bug fix update Advisory ID: RHSA-2018:2789-01 Product: Red Hat Enterprise MRG for RHEL-6 Advisory URL: https://access.redhat.com/errata/RHSA-2018:2789 Issue date: 2018-09-25 CVE Names: CVE-2018-5390 ==================================================================== 1. Summary: An update for kernel-rt is now available for Red Hat Enterprise MRG 2. 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. 2. Relevant releases/architectures: Red Hat MRG Realtime for RHEL 6 Server v.2 - noarch, x86_64 3. Description: The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements. Security Fix(es): * A flaw named SegmentSmack was found in the way the Linux kernel handled specially crafted TCP packets. A remote attacker could use this flaw to trigger time and calculation expensive calls to tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() functions by sending specially modified packets within ongoing TCP sessions which could lead to a CPU saturation and hence a denial of service on the system. Maintaining the denial of service condition requires continuous two-way TCP sessions to a reachable open port, thus the attacks cannot be performed using spoofed IP addresses. (CVE-2018-5390) Red Hat would like to thank Juha-Matti Tilli (Aalto University - Department of Communications and Networking and Nokia Bell Labs) for reporting this issue. Bug Fix(es): * The kernel-rt packages have been upgraded to the 3.10.0-693.39.1 source tree, which provides a number of bug fixes over the previous version. (BZ#1616431) * Previously, preemption was enabled too early after a context switch. If a task was migrated to another CPU after a context switch, a mismatch between CPU and runqueue during load balancing sometimes occurred. Consequently, a runnable task on an idle CPU failed to run, and the operating system became unresponsive. This update disables preemption in the schedule_tail() function. As a result, CPU migration during post-schedule processing no longer occurs, which prevents the above mismatch. The operating system no longer hangs due to this bug. (BZ#1618466) 4. 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. 5. Bugs fixed (https://bugzilla.redhat.com/): 1601704 - CVE-2018-5390 kernel: TCP segments with random offsets allow a remote denial of service (SegmentSmack) 1616431 - update the MRG 2.5.z 3.10 kernel-rt sources 1618466 - RT system hang due to wrong of rq's nr_running [MRG-RT] 6. Package List: Red Hat MRG Realtime for RHEL 6 Server v.2: Source: kernel-rt-3.10.0-693.39.1.rt56.629.el6rt.src.rpm noarch: kernel-rt-doc-3.10.0-693.39.1.rt56.629.el6rt.noarch.rpm kernel-rt-firmware-3.10.0-693.39.1.rt56.629.el6rt.noarch.rpm x86_64: kernel-rt-3.10.0-693.39.1.rt56.629.el6rt.x86_64.rpm kernel-rt-debug-3.10.0-693.39.1.rt56.629.el6rt.x86_64.rpm kernel-rt-debug-debuginfo-3.10.0-693.39.1.rt56.629.el6rt.x86_64.rpm kernel-rt-debug-devel-3.10.0-693.39.1.rt56.629.el6rt.x86_64.rpm kernel-rt-debuginfo-3.10.0-693.39.1.rt56.629.el6rt.x86_64.rpm kernel-rt-debuginfo-common-x86_64-3.10.0-693.39.1.rt56.629.el6rt.x86_64.rpm kernel-rt-devel-3.10.0-693.39.1.rt56.629.el6rt.x86_64.rpm kernel-rt-trace-3.10.0-693.39.1.rt56.629.el6rt.x86_64.rpm kernel-rt-trace-debuginfo-3.10.0-693.39.1.rt56.629.el6rt.x86_64.rpm kernel-rt-trace-devel-3.10.0-693.39.1.rt56.629.el6rt.x86_64.rpm kernel-rt-vanilla-3.10.0-693.39.1.rt56.629.el6rt.x86_64.rpm kernel-rt-vanilla-debuginfo-3.10.0-693.39.1.rt56.629.el6rt.x86_64.rpm kernel-rt-vanilla-devel-3.10.0-693.39.1.rt56.629.el6rt.x86_64.rpm These packages are GPG signed by Red Hat for security. Our key and details on how to verify the signature are available from https://access.redhat.com/security/team/key/ 7. References: https://access.redhat.com/security/cve/CVE-2018-5390 https://access.redhat.com/security/updates/classification/#important 8. Contact: The Red Hat security contact is . More contact details at https://access.redhat.com/security/team/contact/ Copyright 2018 Red Hat, Inc. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIVAwUBW6qY8tzjgjWX9erEAQjRShAAnmRkv6mo27RSa3mR4eLxu7ropKwD9Zfm YfD67ILqkL5SQc1XGK/q3HAsIrIK3HEvfvzeuBG7Z1HMKZPIfPDZdXD+AjQmsdvG oQumulHt8Ykcx798cCj6d0ZBpzu1se15tfiDlyyaSVscV+yYrGYatZkn1llqVEl5 Ab5sWkE3zHlm9aEWJn4WVluhjbOCb4LuUGyYBkMKpC4uF7bYLGQHG3nJ33YYKxzG DIuVCmuTSLyOh+If7RyQrTgf1QTTgfupHBZ1UkqRj5vV1mie4+1rSujQsCR4eFhz ngIp/kPaXedPFd26CxRrEMmdtV1fZvsvhTEgijEmlOVnmQURBcj068nqDafVIqXS t0Z/tiRUbauq+83qdrPS9y2YizwQfMC8/Ehos6deQ6ac2hTMgq2wqs/VKGgHjpe4 WAnh8y9Ii87bgQyZhHqBfuQtsQ2F0ABvQKcIrNFitiPxzfRXUT7PwOe1TnC1ZNIx qGpSCt2z4TzcvFHUghfnitbyBOJT/CCEIZnlI8kLl5809/94I9mbqfuYtDDN7qmv IdG2gQpiCM1agcGO2U+XZbmnBbex7gAkZtl2hE3uAWkjfKEZKA3f/pye/zHwFKko IrGagq3BrghsNcpEObEI+8IsLnMaFtLQfuEWHNn2yhFZFMSTtDmkD6mfHt+xIaKr V4OlIJQJyq8=s8NF -----END PGP SIGNATURE----- -- RHSA-announce mailing list RHSA-announce@redhat.com https://www.redhat.com/mailman/listinfo/rhsa-announce