CVE-2023-53000

In the Linux kernel, the following vulnerability has been resolved:

netlink: prevent potential spectre v1 gadgets

Most netlink attributes are parsed and validated from __nla_validate_parse() or validate_nla()

u16 type = nla_type(nla);

if (type == 0 || type > maxtype) {
    /* error or continue */
}

@type is then used as an array index and can be used as a Spectre v1 gadget.

array_index_nospec() can be used to prevent leaking content of kernel memory to malicious users.

This should take care of vast majority of netlink uses, but an audit is needed to take care of others where validation is not yet centralized in core netlink functions.

The bug is that potentially could happen read out of bounds for the usage of variable type in validate_nla and __nla_validate_parse functions. However required checks of this type value (validation of array index) existed before the fix too, so no known scenario how to trigger the bug. The security impact is limited. For the Red Hat Enterprise Linux 9 and later versions the bug already fixed.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.