QID 353150

Date Published: 2022-02-01

QID 353150: Amazon Linux Security Advisory for kernel : ALAS2KERNEL-5.4-2022-001

a null pointer dereference flaw was found in the linux kernels gpu nouveau driver functionality in the way the user calls ioctl drm_ioctl_nouveau_channel_alloc.
This flaw allows a local user to crash the system. (
( CVE-2020-25639) an issue was discovered in the linux kernel 3.11 through 5.10.16, as used by xen.
To service requests to the pv backend, the driver maps grant references provided by the frontend.
In this process, errors may be encountered.
In one case, an error encountered earlier might be discarded by later processing, resulting in the caller assuming successful mapping, and hence subsequent operations trying to access space that wasnt mapped.
In another case, internal state would be insufficiently updated, preventing safe recovery from the error.
This affects drivers/block/xen-blkback/blkback.c. (
( CVE-2021-26930) an issue was discovered in the linux kernel 2.6.39 through 5.10.16, as used in xen.
Block, net, and scsi backends consider certain errors a plain bug, deliberately causing a kernel crash.
For errors potentially being at least under the influence of guests (such as out of memory conditions), it isnt correct to assume a plain bug.
Memory allocations potentially causing such crashes occur only when linux is running in pv mode, though.
This affects drivers/block/xen-blkback/blkback.c and drivers/xen/xen-scsiback.c. (
( CVE-2021-26931) an issue was discovered in the linux kernel 3.2 through 5.10.16, as used by xen.
Unfortunately, when running in pv mode, the linux backend drivers mishandle this: some errors are ignored, effectively implying their success from the success of related batch elements.
( CVE-2021-28038)



Note: The preceding description block is extracted directly from the security advisory. Using automation, we have attempted to clean and format it as much as possible without introducing additional issues.

Successful exploitation of this vulnerability could lead to a securitybreach or could affect integrity, availability, and confidentiality.

  • CVSS V3 rated as High - 7.8 severity.
  • CVSS V2 rated as Medium - 4.6 severity.
    • Solution
    Please refer to Amazon advisory: ALAS2KERNEL-5.4-2022-001 for affected packages and patching details, or update with your package manager.
    Vendor References

    CVEs related to QID 353150

    CVE-2021-26931 | CVE-2021-27365 | CVE-2021-28038 | CVE-2021-27364 | CVE-2021-27363 | CVE-2021-26930 | CVE-2021-26932 | CVE-2020-25639 |
    Software Advisories
    Advisory ID Software Component Link
    ALAS2KERNEL-5.4-2022-001 Amazon Linux 2 URL Logo alas.aws.amazon.com/AL2/ALASKERNEL-5.4-2022-001.html
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