Linux · Linux Kernel · CVE-2021-47562
Name of the Vulnerable Software and Affected Versions:
Linux kernel versions prior to 5.15.0-rc5+
Description:
The vulnerability is related to a NULL pointer dereference in the Linux kernel, specifically in the ice driver. The issue occurs when the Rx queue count differs from the Tx queue count, causing a hidden bug to be exposed. The vulnerability can be triggered when ethtool -L is used and XDP rings are configured. The estimated number of potentially affected devices is not specified. There is no information about real-world incidents where this issue was exploited.
Technical details about exploitation include:
- The `ice vsi free arrays()` function is vulnerable.
- The `ice vsi rebuild()` function is also affected.
- The `devres remove()` function is involved in the NULL pointer dereference.
- The `ethtool -L` command can trigger the vulnerability when XDP rings are configured.
Recommendations:
To resolve the issue, update the Linux kernel to a version that includes the fix for the ice driver, taking into account the value that `num possible cpus()` yields in addition to `vsi->alloc txq` instead of doubling the latter.
At the moment, there is no information about a newer version that contains a fix for this vulnerability.