Red Hat Security Advisory: kernel security and bug fix update
🔗 CVE IDs covered (9)
📋 Description
CVE-2020-0465 — kernel: out of bounds write in hid-multitouch.c may lead to escalation of privilege CVE-2020-0466 — kernel: use after free in eventpoll.c may lead to escalation of privilege CVE-2021-0920 — kernel: Use After Free in unix_gc() which could result in a local privilege escalation CVE-2021-3564 — kernel: double free in bluetooth subsystem when the HCI device initialization fails CVE-2021-3573 — kernel: use-after-free in function hci_sock_bound_ioctl() CVE-2021-3752 — kernel: possible use-after-free in bluetooth module CVE-2021-4155 — kernel: xfs: raw block device data leak in XFS_IOC_ALLOCSP IOCTL CVE-2022-0330 — kernel: possible privileges escalation due to missing TLB flush CVE-2022-22942 — kernel: failing usercopy allows for use-after-free exploitation
🎯 Affected products162
- Red Hat Enterprise Linux Client (v. 7)
- Red Hat Enterprise Linux Client Optional (v. 7)
- Red Hat Enterprise Linux ComputeNode Optional (v. 7)
- Red Hat Enterprise Linux Server (v. 7)
- Red Hat Enterprise Linux Server Optional (v. 7)
- Red Hat Enterprise Linux Workstation (v. 7)
- Red Hat Enterprise Linux Workstation Optional (v. 7)
- bpftool-0:3.10.0-1160.59.1.el7.ppc64 as a component of Red Hat Enterprise Linux Server (v. 7)
- bpftool-0:3.10.0-1160.59.1.el7.ppc64le as a component of Red Hat Enterprise Linux Server (v. 7)
- bpftool-0:3.10.0-1160.59.1.el7.s390x as a component of Red Hat Enterprise Linux Server (v. 7)
- bpftool-0:3.10.0-1160.59.1.el7.x86_64 as a component of Red Hat Enterprise Linux Client (v. 7)
- bpftool-0:3.10.0-1160.59.1.el7.x86_64 as a component of Red Hat Enterprise Linux Server (v. 7)
- bpftool-0:3.10.0-1160.59.1.el7.x86_64 as a component of Red Hat Enterprise Linux Workstation (v. 7)
- bpftool-debuginfo-0:3.10.0-1160.59.1.el7.ppc64 as a component of Red Hat Enterprise Linux Server (v. 7)
- bpftool-debuginfo-0:3.10.0-1160.59.1.el7.ppc64 as a component of Red Hat Enterprise Linux Server Optional (v. 7)
- bpftool-debuginfo-0:3.10.0-1160.59.1.el7.ppc64le as a component of Red Hat Enterprise Linux Server (v. 7)
- bpftool-debuginfo-0:3.10.0-1160.59.1.el7.ppc64le as a component of Red Hat Enterprise Linux Server Optional (v. 7)
- bpftool-debuginfo-0:3.10.0-1160.59.1.el7.s390x as a component of Red Hat Enterprise Linux Server (v. 7)
- bpftool-debuginfo-0:3.10.0-1160.59.1.el7.x86_64 as a component of Red Hat Enterprise Linux Client (v. 7)
- bpftool-debuginfo-0:3.10.0-1160.59.1.el7.x86_64 as a component of Red Hat Enterprise Linux Client Optional (v. 7)
- bpftool-debuginfo-0:3.10.0-1160.59.1.el7.x86_64 as a component of Red Hat Enterprise Linux ComputeNode Optional (v. 7)
- bpftool-debuginfo-0:3.10.0-1160.59.1.el7.x86_64 as a component of Red Hat Enterprise Linux Server (v. 7)
- bpftool-debuginfo-0:3.10.0-1160.59.1.el7.x86_64 as a component of Red Hat Enterprise Linux Server Optional (v. 7)
- bpftool-debuginfo-0:3.10.0-1160.59.1.el7.x86_64 as a component of Red Hat Enterprise Linux Workstation (v. 7)
- bpftool-debuginfo-0:3.10.0-1160.59.1.el7.x86_64 as a component of Red Hat Enterprise Linux Workstation Optional (v. 7)
- kernel-0:3.10.0-1160.59.1.el7.ppc64 as a component of Red Hat Enterprise Linux Server (v. 7)
- kernel-0:3.10.0-1160.59.1.el7.ppc64le as a component of Red Hat Enterprise Linux Server (v. 7)
- kernel-0:3.10.0-1160.59.1.el7.s390x as a component of Red Hat Enterprise Linux Server (v. 7)
- kernel-0:3.10.0-1160.59.1.el7.src as a component of Red Hat Enterprise Linux Client (v. 7)
- kernel-0:3.10.0-1160.59.1.el7.src as a component of Red Hat Enterprise Linux Server (v. 7)
- +132 more not shown
✅ Remediation
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. Workaround: As the multitouch module will be auto-loaded when required, its use can be disabled by preventing the module from loading with the following instructions: # echo "install hid-multitouch /bin/true" >> /etc/modprobe.d/disable-hid-multitouch.conf The system may need to be restarted if the hid-multitouch module is loaded. In most circumstances, a kernel modules will be unable to be unloaded while in use. If the system requires this module to work correctly, this mitigation may not be suitable. If you need further assistance, see KCS article https://access.redhat.com/solutions/41278 or contact Red Hat Global Support Services. Workaround: Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible. Workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. Workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising easThe required privileges is CAP_NET_ADMIN capabilities. This would require a privileged user with CAP_SYS_ADMIN or root to be able to abuse this flaw reducing its attack space.e of use and deployment, applicability to widespread installation base or stability. Workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation baser or stability. The possible solution is to disable Bluetooth completely: https://access.redhat.com/solutions/2682931 Workaround: This issue can be mitigated by ensuring xfs_alloc_file_space is not called with "0" as an argument. This can be done with a SystemTap script (which resets "0" with XFS_BMAPI_PREALLOC), below are the steps: 1) Save the following script in a 'CVE-2021-4155.stp' file --- On Red Hat Enterprise Linux 6 --- probe module("xfs").function("xfs_alloc_file_space") { if ($alloc_type == 0) $alloc_type = 0x40; # XFS_BMAPI_PREALLOC } --- On Red Hat Enterprise Linux 6 --- --- On Red Hat Enterprise Linux 7 onwards --- probe module("xfs").function("xfs_alloc_file_space") { if ($alloc_type == 0) $alloc_type = 0x8; # XFS_BMAPI_PREALLOC } --- On Red Hat Enterprise Linux 7 onwards --- 2) Install systemtap package and its dependencies # yum install -y systemtap systemtap-runtime # yum install -y kernel-devel kernel-debuginfo 3) Build the mitigation kernel module as root. # stap -r `uname -r` -m cve_2021_4155.ko -g CVE-2021-4155.stp -p4 4) Load the mitigation module as root # staprun -L cve_2021_4155.ko What is SystemTap and how to use it? https://access.redhat.com/solutions/5441 Workaround: Mitigation for this issue is to skip loading the affected module vmwgfx onto the system until we have a fix available. This can be done by a blacklist mechanism and ensures the driver is not loaded at the boot time. ~~~ How do I blacklist a kernel module to prevent it from loading automatically? https://access.redhat.com/solutions/41278 ~~~
🔗 References (12)
- selfhttps://access.redhat.com/errata/RHSA-2022:0620
- externalhttps://access.redhat.com/security/updates/classification/#important
- externalhttps://bugzilla.redhat.com/show_bug.cgi?id=1920471
- externalhttps://bugzilla.redhat.com/show_bug.cgi?id=1920480
- externalhttps://bugzilla.redhat.com/show_bug.cgi?id=1964139
- externalhttps://bugzilla.redhat.com/show_bug.cgi?id=1966578
- externalhttps://bugzilla.redhat.com/show_bug.cgi?id=1999544
- externalhttps://bugzilla.redhat.com/show_bug.cgi?id=2031930
- externalhttps://bugzilla.redhat.com/show_bug.cgi?id=2034813
- externalhttps://bugzilla.redhat.com/show_bug.cgi?id=2042404
- externalhttps://bugzilla.redhat.com/show_bug.cgi?id=2044809
- selfhttps://security.access.redhat.com/data/csaf/v2/advisories/2022/rhsa-2022_0620.json