CVE-2020-36787: media: aspeed: fix clock handling logic

Published Feb 28, 2024
·
Updated

In the Linux kernel, the following vulnerability has been resolved:

media: aspeed: fix clock handling logic

Video engine uses eclk and vclk for its clock sources and its reset control is coupled with eclk so the current clock enabling sequence works like below.

Enable eclk De-assert Video Engine reset 10ms delay Enable vclk

It introduces improper reset on the Video Engine hardware and eventually the hardware generates unexpected DMA memory transfers that can corrupt memory region in random and sporadic patterns. This issue is observed very rarely on some specific AST2500 SoCs but it causes a critical kernel panic with making a various shape of signature so it's extremely hard to debug. Moreover, the issue is observed even when the video engine is not actively used because udevd turns on the video engine hardware for a short time to make a query in every boot.

To fix this issue, this commit changes the clock handling logic to make the reset de-assertion triggered after enabling both eclk and vclk. Also, it adds clkunprepare call for a case when probe fails.

clk: ast2600: fix reset settings for eclk and vclk Video engine reset setting should be coupled with eclk to match it with the setting for previous Aspeed SoCs which is defined in clk-aspeed.c since all Aspeed SoCs are sharing a single video engine driver. Also, reset bit 6 is defined as 'Video Engine' reset in datasheet so it should be de-asserted when eclk is enabled. This commit fixes the setting.

Affected Software

94 affected componentsFixes available
Linux Linux kernel>=5.0<5.4.119
Linux Linux kernel>=5.5<5.10.37
Linux Linux kernel>=5.11<5.11.21
Linux Linux kernel>=5.12<5.12.4
ubuntu/linux-hwe-edge*
ubuntu/linux-aws-5.4<5.4.0-1051.53~18.04.1
5.4.0-1051.53~18.04.1
ubuntu/linux-azure-5.4<5.4.0-1051.53~18.04.1
5.4.0-1051.53~18.04.1
ubuntu/linux-gcp-5.4<5.4.0-1046.49~18.04.1
5.4.0-1046.49~18.04.1
ubuntu/linux-hwe-5.4<5.4.0-77.86~18.04.1
5.4.0-77.86~18.04.1
ubuntu/linux-oracle-5.4<5.4.0-1048.52~18.04.1
5.4.0-1048.52~18.04.1
ubuntu/linux-raspi-5.4<5.4.0-1038.41~18.04.1
5.4.0-1038.41~18.04.1
ubuntu/linux-aws-5.0*
ubuntu/linux-aws-5.3*
ubuntu/linux-azure*
ubuntu/linux-azure-5.3*
ubuntu/linux-azure-edge*
ubuntu/linux-gcp*
ubuntu/linux-gcp-5.3*
ubuntu/linux-gke-4.15*
ubuntu/linux-gke-5.4*
ubuntu/linux-gkeop-5.4*
ubuntu/linux-hwe*
ubuntu/linux-hwe-edge*
ubuntu/linux-oem*
ubuntu/linux-oracle-5.0*
ubuntu/linux-oracle-5.3*
ubuntu/linux<5.4.0-77.86
5.4.0-77.86
ubuntu/linux-aws<5.4.0-1051.53
5.4.0-1051.53
ubuntu/linux-azure<5.4.0-1051.53
5.4.0-1051.53
ubuntu/linux-bluefield<5.4.0-1013.16
5.4.0-1013.16
ubuntu/linux-gcp<5.4.0-1046.49
5.4.0-1046.49
ubuntu/linux-gkeop<5.4.0-1018.19
5.4.0-1018.19
ubuntu/linux-kvm<5.4.0-1041.42
5.4.0-1041.42
ubuntu/linux-oracle<5.4.0-1048.52
5.4.0-1048.52
ubuntu/linux-raspi<5.4.0-1038.41
5.4.0-1038.41
ubuntu/linux-aws-5.11*
ubuntu/linux-aws-5.13*
ubuntu/linux-aws-5.8*
ubuntu/linux-azure-5.11*
ubuntu/linux-azure-5.13*
ubuntu/linux-azure-5.8*
ubuntu/linux-azure-fde*
ubuntu/linux-gcp-5.11*
ubuntu/linux-gcp-5.13*
ubuntu/linux-gcp-5.8*
ubuntu/linux-gke*
ubuntu/linux-gke-5.15*
ubuntu/linux-hwe-5.11*
ubuntu/linux-hwe-5.13*
ubuntu/linux-hwe-5.8*
ubuntu/linux-intel-5.13*
ubuntu/linux-oem-5.10*
ubuntu/linux-oem-5.13*
ubuntu/linux-oem-5.6*
ubuntu/linux-oracle-5.11*
ubuntu/linux-oracle-5.13*
ubuntu/linux-oracle-5.8*
ubuntu/linux-raspi2*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.11*
ubuntu/linux-riscv-5.8*
ubuntu/linux-aws-fips<5.4.0-1069.73+fips2
5.4.0-1069.73+fips2
ubuntu/linux-azure-fips<5.4.0-1073.76+fips1
5.4.0-1073.76+fips1
ubuntu/linux-fips<5.4.0-1028.32
5.4.0-1028.32
ubuntu/linux-gcp-fips<5.4.0-1067.71~20.04.1
5.4.0-1067.71~20.04.1
ubuntu/linux-aws-fips*
ubuntu/linux-azure-fips*
ubuntu/linux-fips*
ubuntu/linux-gcp-fips*
ubuntu/linux-allwinner-5.19*
ubuntu/linux-aws-5.19*
ubuntu/linux-aws-6.2*
ubuntu/linux-azure-5.19*
ubuntu/linux-azure-6.2*
ubuntu/linux-azure-fde-5.19*
ubuntu/linux-azure-fde-6.2*
ubuntu/linux-gcp-5.19*
ubuntu/linux-gcp-6.2*
ubuntu/linux-hwe-5.19*
ubuntu/linux-hwe-6.2*
ubuntu/linux-intel-iot-realtime*
ubuntu/linux-lowlatency-hwe-5.19*
ubuntu/linux-lowlatency-hwe-6.2*
ubuntu/linux-nvidia-6.2*
ubuntu/linux-oem-5.17*
ubuntu/linux-oem-6.0*
ubuntu/linux-oem-6.1*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.19*
ubuntu/linux-starfive-5.19*
ubuntu/linux-starfive-6.2*
ubuntu/linux-raspi-realtime*
ubuntu/linux-vmware*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade ubuntu/linux-aws-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1051.53~18.04.1
  2. Upgrade

    Upgrade ubuntu/linux-azure-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1051.53~18.04.1
  3. Upgrade

    Upgrade ubuntu/linux-gcp-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1046.49~18.04.1
  4. Upgrade

    Upgrade ubuntu/linux-hwe-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-77.86~18.04.1
  5. Upgrade

    Upgrade ubuntu/linux-oracle-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1048.52~18.04.1
  6. Upgrade

    Upgrade ubuntu/linux-raspi-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1038.41~18.04.1
  7. Upgrade

    Upgrade ubuntu/linux to a version that resolves this vulnerability.

    Fixed in 5.4.0-77.86
  8. Upgrade

    Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.

    Fixed in 5.4.0-1051.53
  9. Upgrade

    Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.

    Fixed in 5.4.0-1051.53
  10. Upgrade

    Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.

    Fixed in 5.4.0-1013.16
  11. Upgrade

    Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.

    Fixed in 5.4.0-1046.49
  12. Upgrade

    Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.

    Fixed in 5.4.0-1018.19
  13. Upgrade

    Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.

    Fixed in 5.4.0-1041.42
  14. Upgrade

    Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.

    Fixed in 5.4.0-1048.52
  15. Upgrade

    Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.

    Fixed in 5.4.0-1038.41
  16. Upgrade

    Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.

    Fixed in 5.4.0-1069.73+fips2
  17. Upgrade

    Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.

    Fixed in 5.4.0-1073.76+fips1
  18. Upgrade

    Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.

    Fixed in 5.4.0-1028.32
  19. Upgrade

    Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.

    Fixed in 5.4.0-1067.71~20.04.1
  20. Configuration

    Change the clock handling logic so Video Engine reset de-assertion occurs only after both eclk and vclk are enabled; also call clk_unprepare when probe fails.

    Linux kernel Aspeed video engine driver Video Engine reset sequencing = Enable eclk and vclk before de-asserting the Video Engine reset

Event History

Feb 28, 2024
CVE Published
via MITRE·08:13 AM
Data Sourced
via MITRE·08:13 AM
DescriptionSeverity
Data Sourced
via OSV·09:15 AM
DescriptionSeverityAffected Software
Data Sourced
via NVD·09:15 AM
RemedyDescriptionSeverityAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2020-36787?

CVE-2020-36787 has a severity rating of medium.

2

How do I fix CVE-2020-36787?

To fix CVE-2020-36787, users should update their Linux kernel to a version higher than 5.12.4.

3

What versions of the Linux kernel are affected by CVE-2020-36787?

CVE-2020-36787 affects Linux kernel versions from 5.0 to 5.12.4.

4

What components are impacted by CVE-2020-36787?

CVE-2020-36787 impacts the clock handling logic used by the video engine in the Linux kernel.

5

Is there a workaround for CVE-2020-36787?

There are no known workarounds for CVE-2020-36787, so updating the kernel is recommended.

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