Medium: kernel

Issue Overview:

A flaw use-after-free in function sco_sock_sendmsg() of the Linux kernel HCI subsystem was found in the way user calls ioct UFFDIO_REGISTER or other way triggers race condition of the call sco_conn_del() together with the call sco_sock_sendmsg() with the expected controllable faulting memory page. A privileged local user could use this flaw to crash the system or escalate their privileges on the system. (CVE-2021-3640)

A flaw was found in the Linux SCTP stack. A blind attacker may be able to kill an existing SCTP association through invalid chunks if the attacker knows the IP-addresses and port numbers being used and the attacker can send packets with spoofed IP addresses. (CVE-2021-3772)

A memory leak flaw in the Linux kernel’s hugetlbfs memory usage was found in the way the user maps some regions of memory twice using shmget() which are aligned to PUD alignment with the fault of some of the memory pages. A local user could use this flaw to get unauthorized access to some data. (CVE-2021-4002)

Affected Packages:

kernel

Note:

This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.

Issue Correction:
Run yum update kernel to update your system.

New Packages:

aarch64:  
    kernel-4.14.256-197.484.amzn2.aarch64  
    kernel-headers-4.14.256-197.484.amzn2.aarch64  
    kernel-debuginfo-common-aarch64-4.14.256-197.484.amzn2.aarch64  
    perf-4.14.256-197.484.amzn2.aarch64  
    perf-debuginfo-4.14.256-197.484.amzn2.aarch64  
    python-perf-4.14.256-197.484.amzn2.aarch64  
    python-perf-debuginfo-4.14.256-197.484.amzn2.aarch64  
    kernel-tools-4.14.256-197.484.amzn2.aarch64  
    kernel-tools-devel-4.14.256-197.484.amzn2.aarch64  
    kernel-tools-debuginfo-4.14.256-197.484.amzn2.aarch64  
    kernel-devel-4.14.256-197.484.amzn2.aarch64  
    kernel-debuginfo-4.14.256-197.484.amzn2.aarch64  
  
i686:  
    kernel-headers-4.14.256-197.484.amzn2.i686  
  
src:  
    kernel-4.14.256-197.484.amzn2.src  
  
x86_64:  
    kernel-4.14.256-197.484.amzn2.x86_64  
    kernel-headers-4.14.256-197.484.amzn2.x86_64  
    kernel-debuginfo-common-x86_64-4.14.256-197.484.amzn2.x86_64  
    perf-4.14.256-197.484.amzn2.x86_64  
    perf-debuginfo-4.14.256-197.484.amzn2.x86_64  
    python-perf-4.14.256-197.484.amzn2.x86_64  
    python-perf-debuginfo-4.14.256-197.484.amzn2.x86_64  
    kernel-tools-4.14.256-197.484.amzn2.x86_64  
    kernel-tools-devel-4.14.256-197.484.amzn2.x86_64  
    kernel-tools-debuginfo-4.14.256-197.484.amzn2.x86_64  
    kernel-devel-4.14.256-197.484.amzn2.x86_64  
    kernel-debuginfo-4.14.256-197.484.amzn2.x86_64  
    kernel-livepatch-4.14.256-197.484-1.0-0.amzn2.x86_64  

Additional References

Red Hat: CVE-2021-3640, CVE-2021-3772, CVE-2021-4002

Mitre: CVE-2021-3640, CVE-2021-3772, CVE-2021-4002