CVE-2021-47587

MEDIUM
Published Jun 19, 2024 Modified Nov 21, 2024 CWE-667

Description

In the Linux kernel, the following vulnerability has been resolved: net: systemport: Add global locking for descriptor lifecycle The descriptor list is a shared resource across all of the transmit queues, and the locking mechanism used today only protects concurrency across a given transmit queue between the transmit and reclaiming. This creates an opportunity for the SYSTEMPORT hardware to work on corrupted descriptors if we have multiple producers at once which is the case when using multiple transmit queues. This was particularly noticeable when using multiple flows/transmit queues and it showed up in interesting ways in that UDP packets would get a correct UDP header checksum being calculated over an incorrect packet length. Similarly TCP packets would get an equally correct checksum computed by the hardware over an incorrect packet length. The SYSTEMPORT hardware maintains an internal descriptor list that it re-arranges when the driver produces a new descriptor anytime it writes to the WRITE_PORT_{HI,LO} registers, there is however some delay in the hardware to re-organize its descriptors and it is possible that concurrent TX queues eventually break this internal allocation scheme to the point where the length/status part of the descriptor gets used for an incorrect data buffer. The fix is to impose a global serialization for all TX queues in the short section where we are writing to the WRITE_PORT_{HI,LO} registers which solves the corruption even with multiple concurrent TX queues being used.

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CVSS v3.1 Score

5.5
MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-667 CWE-667

Affected Products

Vendor Product
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel

References

Advisories & Patches

https://git.kernel.org/stable/c/595a684fa6f23b21958379a18cfa83862c73c2e1 https://git.kernel.org/stable/c/6e1011cd183faae8daff275c72444edcdfe0d473 https://git.kernel.org/stable/c/8b8e6e782456f1ce02a7ae914bbd5b1053f0b034 https://git.kernel.org/stable/c/8ed2f5d08d6e59f8c78b2869bfb95d0be32c094c https://git.kernel.org/stable/c/c675256a7f131f5ba3f331efb715e8f31ea0e392 https://git.kernel.org/stable/c/de57f62f76450b934de8203711bdc4f7953c3421 https://git.kernel.org/stable/c/eb4687c7442942e115420a30185f8d83faf37696 https://git.kernel.org/stable/c/f3fde37d3f0d429f0fcce214cb52588a9e21260e https://git.kernel.org/stable/c/595a684fa6f23b21958379a18cfa83862c73c2e1 https://git.kernel.org/stable/c/6e1011cd183faae8daff275c72444edcdfe0d473 https://git.kernel.org/stable/c/8b8e6e782456f1ce02a7ae914bbd5b1053f0b034 https://git.kernel.org/stable/c/8ed2f5d08d6e59f8c78b2869bfb95d0be32c094c https://git.kernel.org/stable/c/c675256a7f131f5ba3f331efb715e8f31ea0e392 https://git.kernel.org/stable/c/de57f62f76450b934de8203711bdc4f7953c3421 https://git.kernel.org/stable/c/eb4687c7442942e115420a30185f8d83faf37696 https://git.kernel.org/stable/c/f3fde37d3f0d429f0fcce214cb52588a9e21260e

Frequently Asked Questions

What is CVE-2021-47587? +
In the Linux kernel, the following vulnerability has been resolved: net: systemport: Add global locking for descriptor lifecycle The descriptor list is a shared resource across all of the transmit queues, and the locking mechanism used today only protects concurrency across a given transmit queue between the transmit and reclaiming. This creates an opportunity for the SYSTEMPORT hardware to work on corrupted descriptors if we have multiple producers at once which is the case when using multiple transmit queues. This was particularly noticeable when using multiple flows/transmit queues and it showed up in interesting ways in that UDP packets would get a correct UDP header checksum being calculated over an incorrect packet length. Similarly TCP packets would get an equally correct checksum computed by the hardware over an incorrect packet length. The SYSTEMPORT hardware maintains an internal descriptor list that it re-arranges when the driver produces a new descriptor anytime it writes to the WRITE_PORT_{HI,LO} registers, there is however some delay in the hardware to re-organize its descriptors and it is possible that concurrent TX queues eventually break this internal allocation scheme to the point where the length/status part of the descriptor gets used for an incorrect data buffer. The fix is to impose a global serialization for all TX queues in the short section where we are writing to the WRITE_PORT_{HI,LO} registers which solves the corruption even with multiple concurrent TX queues being used. It has a CVSS v3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2021-47587? +
CVE-2021-47587 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.
What products are affected by CVE-2021-47587? +
CVE-2021-47587 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2021-47587? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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