CVE-2021-47556

ethtool: ioctl: fix potential NULL deref in ethtool_set_coalesce()

Description

In the Linux kernel, the following vulnerability has been resolved: ethtool: ioctl: fix potential NULL deref in ethtool_set_coalesce() ethtool_set_coalesce() now uses both the .get_coalesce() and .set_coalesce() callbacks. But the check for their availability is buggy, so changing the coalesce settings on a device where the driver provides only _one_ of the callbacks results in a NULL pointer dereference instead of an -EOPNOTSUPP. Fix the condition so that the availability of both callbacks is ensured. This also matches the netlink code. Note that reproducing this requires some effort - it only affects the legacy ioctl path, and needs a specific combination of driver options: - have .get_coalesce() and .coalesce_supported but no .set_coalesce(), or - have .set_coalesce() but no .get_coalesce(). Here eg. ethtool doesn't cause the crash as it first attempts to call ethtool_get_coalesce() and bails out on error.

Category

5.5
CVSS
Severity: Medium
CVSS 3.1 •
EPSS 0.05%
Affected: Linux Linux
Affected: Linux Linux
Published at:
Updated at:

References

Link Tags
https://git.kernel.org/stable/c/abfdd9e2f0f9699015d72317f74154d3e53664e6 patch
https://git.kernel.org/stable/c/0276af2176c78771da7f311621a25d7608045827 patch

Frequently Asked Questions

What is the severity of CVE-2021-47556?
CVE-2021-47556 has been scored as a medium severity vulnerability.
How to fix CVE-2021-47556?
To fix CVE-2021-47556, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-47556 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-47556 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-47556?
CVE-2021-47556 affects Linux Linux, Linux Linux.
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