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 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):

• kernel: size_t-to-int conversion vulnerability in the filesystem layer (CVE-2021-33909)
• kernel: use-after-free in net/bluetooth/hci_event.c when destroying an hci_chan (CVE-2021-33034)
• kernel: use-after-free in show_numa_stats function (CVE-2019-20934)
• kernel: mishandles invalid descriptors in drivers/media/usb/gspca/xirlink_cit.c (CVE-2020-11668)
• kernel: use-after-free in cipso_v4_genopt in net/ipv4/cipso_ipv4.c (CVE-2021-33033)

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):

• [RHEL7.9.z] n_tty_open: "BUG: unable to handle kernel paging request" (BZ#1872778)
• [ESXi][RHEL7.8]"qp_alloc_hypercall result = -20" / "Could not attach to queue pair with -20" with vSphere Fault Tolerance enabled (BZ#1892237)
• [RHEL7.9][s390x][Regression] Sino Nomine swapgen IBM z/VM emulated DASD with DIAG driver returns EOPNOTSUPP (BZ#1910395)
• False-positive hard lockup detected while processing the thread state information (SysRq-T) (BZ#1912221)
• RHEL7.9 zstream - s390x LPAR with NVMe SSD will panic when it has 32 or more IFL (pci) (BZ#1917943)
• The NMI watchdog detected a hard lockup while printing RCU CPU stall warning messages to the serial console (BZ#1924688)
• nvme hangs when trying to allocate reserved tag (BZ#1926825)
• [REGRESSION] "call into AER handling regardless of severity" triggers do_recovery() unnecessarily on correctable PCIe errors (BZ#1933663)
• Module nvme_core: A double free of the kmalloc-512 cache between nvme_trans_log_temperature() and nvme_get_log_page(). (BZ#1946793)
• sctp - SCTP_CMD_TIMER_START queues active timer kernel BUG at kernel/timer.c:1000! (BZ#1953052)
• [Hyper-V][RHEL-7]When CONFIG_NET_POLL_CONTROLLER is set, mainline commit 2a7f8c3b1d3fee is needed (BZ#1953075)
• Kernel panic at cgroup_is_descendant (BZ#1957719)
• [Hyper-V][RHEL-7]Commits To Fix Kdump Failures (BZ#1957803)
• IGMPv2 JOIN packets incorrectly routed to loopback (BZ#1958339)
• [CKI kernel builds]: x86 binaries in non-x86 kernel rpms breaks systemtap [7.9.z] (BZ#1960193)
• mlx4: Fix memory allocation in mlx4_buddy_init needed (BZ#1962406)
• incorrect assertion on pi_state->pi_mutex.wait_lock from pi_state_update_owner() (BZ#1965495)

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 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

Fixes

• BZ - 1824792 - CVE-2020-11668 kernel: mishandles invalid descriptors in drivers/media/usb/gspca/xirlink_cit.c
• BZ - 1902788 - CVE-2019-20934 kernel: use-after-free in show_numa_stats function
• BZ - 1961300 - CVE-2021-33033 kernel: use-after-free in cipso_v4_genopt in net/ipv4/cipso_ipv4.c
• BZ - 1961305 - CVE-2021-33034 kernel: use-after-free in net/bluetooth/hci_event.c when destroying an hci_chan
• BZ - 1970273 - CVE-2021-33909 kernel: size_t-to-int conversion vulnerability in the filesystem layer

CVEs

• CVE-2019-20934
• CVE-2020-11668
• CVE-2021-33033
• CVE-2021-33034
• CVE-2021-33909

References

• https://access.redhat.com/security/updates/classification/#important
• https://access.redhat.com/security/vulnerabilities/RHSB-2021-006