RHSA-2021:0336 - Security Advisory

Topic

An update for kernel is now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having a security impact of Moderate. 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):

• kernel: use-after-free in fs/block_dev.c (CVE-2020-15436)
• kernel: Nfsd failure to clear umask after processing an open or create (CVE-2020-35513)

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):

• double free issue in filelayout_alloc_commit_info (BZ#1679980)
• Regression: Plantronics Device SHS2355-11 PTT button does not work after update to 7.7 (BZ#1769502)
• Openstack network node reports unregister_netdevice: waiting for qr-3cec0c92-9a to become free. Usage count = 1 (BZ#1809519)
• dlm: add ability to interrupt waiting for acquire POSIX lock (BZ#1826858)
• [Azure][RHEL7] soft lockups and performance loss occurring during final fsync with parallel dd writes to xfs filesystem in azure instance (BZ#1859364)
• Guest crashed when hotplug vcpus on booting kernel stage (BZ#1866138)
• soft lockup occurs while a thread group leader is waiting on tasklist_waiters in mm_update_next_owner() where a huge number of the thread group members are exiting and trying to take the tasklist_lock. (BZ#1872110)
• [DELL EMC 7.6 BUG] Kioxia CM6 NVMe drive fails to enumerate (BZ#1883403)
• [Hyper-V][RHEL7] Request to included a commit that adds a timeout to vmbus_wait_for_unload (BZ#1888979)
• Unable to discover the LUNs from new storage port (BZ#1889311)
• RHEL 7.9 Kernel panic at ceph_put_snap_realm+0x21 (BZ#1890386)
• A hard lockup occurrs where one task is looping in an sk_lock spinlock that has been taken by another task running timespec64_add_ns(). (BZ#1890911)
• ethtool/mlx5_core provides incorrect SFP module info (BZ#1896756)
• RHEL7.7 - zcrypt: Fix ZCRYPT_PERDEV_REQCNT ioctl (BZ#1896826)
• RHEL7.7 - s390/dasd: Fix zero write for FBA devices (BZ#1896839)
• [Azure]IP forwarding issue in netvsc[7.9.z] (BZ#1898280)
• Security patch for CVE-2020-25212 breaks directory listings via 'ls' on NFS V4.2 shares mounted with selinux enabled labels (BZ#1917504)

Enhancement(s):

• RFE : handle better ERRbaduid on SMB1 (BZ#1847041)

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 Server 7 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 7 x86_64
• Red Hat Enterprise Linux Workstation 7 x86_64
• Red Hat Enterprise Linux Desktop 7 x86_64
• Red Hat Enterprise Linux for IBM z Systems 7 s390x
• Red Hat Enterprise Linux for Power, big endian 7 ppc64
• Red Hat Enterprise Linux for Scientific Computing 7 x86_64
• Red Hat Enterprise Linux for Power, little endian 7 ppc64le
• Red Hat Virtualization Host 4 for RHEL 7 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 7 s390x
• Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, big endian 7 ppc64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, little endian 7 ppc64le

Fixes

• BZ - 1901168 - CVE-2020-15436 kernel: use-after-free in fs/block_dev.c
• BZ - 1905208 - CVE-2020-35513 kernel: fix nfsd failure to clear umask after processing an open or create [rhel-7]
• BZ - 1911309 - CVE-2020-35513 kernel: Nfsd failure to clear umask after processing an open or create
• BZ - 1917504 - Security patch for CVE-2020-25212 breaks directory listings via 'ls' on NFS V4.2 shares mounted with selinux enabled labels

CVEs

• CVE-2020-15436
• CVE-2020-35513

References

• https://access.redhat.com/security/updates/classification/#moderate