CVE-2021-47556

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.

The following products are affected by CVE-2021-47556 vulnerability.

Here, you will find a curated list of external links that provide in-depth information to CVE-2021-47556.

URL	Resource
https://git.kernel.org/stable/c/0276af2176c78771da7f311621a25d7608045827
https://git.kernel.org/stable/c/abfdd9e2f0f9699015d72317f74154d3e53664e6
https://lore.kernel.org/linux-cve-announce/2024052443-CVE-2021-47556-558e@gregkh/T
https://nvd.nist.gov/vuln/detail/CVE-2021-47556
https://www.cve.org/CVERecord?id=CVE-2021-47556