CVE-2024-14040

Technical Description

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

net: nexthop: Increase weight to u16

In CLOS networks, as link failures occur at various points in the network,

ECMP weights of the involved nodes are adjusted to compensate. With high

fan-out of the involved nodes, and overall high number of nodes,

a (non-)ECMP weight ratio that we would like to configure does not fit into

8 bits. Instead of, say, 255:254, we might like to configure something like

1000:999. For these deployments, the 8-bit weight may not be enough.

To that end, in this patch increase the next hop weight from u8 to u16.

Increasing the width of an integral type can be tricky, because while the

code still compiles, the types may not check out anymore, and numerical

errors come up. To prevent this, the conversion was done in two steps.

First the type was changed from u8 to a single-member structure, which

invalidated all uses of the field. This allowed going through them one by

one and audit for type

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References