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Vulnerability · Published May 21, 2024 · Assigned by Linux

CVE-2021-47229PCI: aardvark: Fix kernel panic during PIO transfer

Medium 5.5

In plain English

A medium-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 13% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.5Medium
Exploit odds (30 days)0.2%top 86.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: PCI: aardvark: Fix kernel panic during PIO transfer Trying to start a new PIO transfer by writing value 0 in PIO_START register when previous transfer has not yet completed (which is indicated by value 1 in PIO_START) causes an External Abort on CPU, which results in kernel panic: SError Interrupt on CPU0, code 0xbf000002 -- SError Kernel panic - not syncing: Asynchronous SError Interrupt To prevent kernel panic, it is required to reject a new PIO transfer when previous one has not finished yet. If previous PIO transfer is not finished yet, the kernel may issue a new PIO request only if the previous PIO transfer timed out. In the past the root cause of this issue was incorrectly identified (as it often happens during link retraining or after link down event) and special hack was implemented in Trusted Firmware to catch all SError events in EL3, to ignore errors with code 0xbf000002 and not forwarding any other errors to kernel and instead throw panic from EL3 Trusted Firmware handler. Links to discussion and patches about this issue: https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/commit/?id=3c7dcdac5c50 https://lore.kernel.org/linux-pci/20190316161243.29517-1-repk@triplefau.lt/ https://lore.kernel.org/linux-pci/971be151d24312cc533989a64bd454b4@www.loen.fr/ https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/1541 But the real cause was the fact that during link retraining or after link down event the PIO transfer may take longer time, up to the 1.44s until it times out. This increased probability that a new PIO transfer would be issued by kernel while previous one has not finished yet. After applying this change into the kernel, it is possible to revert the mentioned TF-A hack and SError events do not have to be caught in TF-A EL3.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux5.10.46-1DEBIAN-CVE-2021-47229
Debian:13linux5.10.46-1DEBIAN-CVE-2021-47229
Debian:14linux5.10.46-1DEBIAN-CVE-2021-47229
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2021-47229
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2021-47229
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2021-47229

Affected products (as reported)

VendorProductVersions
Linux Linux 8c39d710363c14ecb09219332869707395d1d495 – before 400e6b1860c8be61388d0b77814c53260f96e17a8c39d710363c14ecb09219332869707395d1d495 – before b00a9aaa4be20ad6e3311fb78a485eae0899e89a8c39d710363c14ecb09219332869707395d1d495 – before 4c90f90a91d75c3c73dd633827c90e8746d9f54d8c39d710363c14ecb09219332869707395d1d495 – before 1a1dbc4473974867fe8c5f195c17b341c8e828678c39d710363c14ecb09219332869707395d1d495 – before 3d213a4ddf49a860be6e795482c17f87e0c82b2a8c39d710363c14ecb09219332869707395d1d495 – before f18139966d072dab8e4398c95ce955a9742e04f7
Linux Linux 4.8

References