CVE-2023-53426: linux kernel Use-After-Free — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: xsk: Fix xsk_diag use-after-free error during socket cleanup Fix a use-after-free error that is possible if the xsk_diag interface is used after the socket has been unbound from the device. This can happen either due to the socket being closed or the device disappearing. In the early days of AF_XDP, the way we tested that a socket was not bound to a device was to simply check if the netdevice pointer in the xsk socket structure was NULL. Later, a better system was introduced by having an explicit state variable in the xsk socket struct. For example, the state of a socket that is on the way to being closed and has been unbound from the device is XSK_UNBOUND. The commit in the Fixes tag below deleted the old way of signalling that a socket is unbound, setting dev to NULL. This in the belief that all code using the old way had been exterminated. That was unfortunately not true as the xsk diagnostics code was still using the old way and thus does not work as intended when a socket is going down. Fix this by introducing a test against the state variable. If the socket is in the state XSK_UNBOUND, simply abort the diagnostic's netlink operation.

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CVSS v3.1 Score

7.8

HIGH

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

Weakness Type (CWE)

CWE-416 Use After Free

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.15.33 — 5.15.132
linux	linux_kernel	5.16.19 — 5.17
linux	linux_kernel	5.17.2 — 6.1.54
linux	linux_kernel	6.2 — 6.5.4

References

Advisories & Patches

https://git.kernel.org/stable/c/3e019d8a05a38abb5c85d4f1e85fda964610aa14 https://git.kernel.org/stable/c/595931912357fa3507e522a7f8a0a76e423c23e4 https://git.kernel.org/stable/c/5979985f2d6b565b6cf0f79a62670a2855c0e96c https://git.kernel.org/stable/c/6436973164ea5506a495f39e56be5aea375e7832

Frequently Asked Questions

What is CVE-2023-53426? +

In the Linux kernel, the following vulnerability has been resolved: xsk: Fix xsk_diag use-after-free error during socket cleanup Fix a use-after-free error that is possible if the xsk_diag interface is used after the socket has been unbound from the device. This can happen either due to the socket being closed or the device disappearing. In the early days of AF_XDP, the way we tested that a socket was not bound to a device was to simply check if the netdevice pointer in the xsk socket structure was NULL. Later, a better system was introduced by having an explicit state variable in the xsk socket struct. For example, the state of a socket that is on the way to being closed and has been unbound from the device is XSK_UNBOUND. The commit in the Fixes tag below deleted the old way of signalling that a socket is unbound, setting dev to NULL. This in the belief that all code using the old way had been exterminated. That was unfortunately not true as the xsk diagnostics code was still using the old way and thus does not work as intended when a socket is going down. Fix this by introducing a test against the state variable. If the socket is in the state XSK_UNBOUND, simply abort the diagnostic's netlink operation. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2023-53426? +

CVE-2023-53426 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2023-53426? +

CVE-2023-53426 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-2023-53426? +

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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