CVE-2026-90086xsk: honor XDP_TX_METADATA in zero-copy path

Official description

In the Linux kernel, the following vulnerability has been resolved: xsk: honor XDP_TX_METADATA in zero-copy path The zero-copy path reads TX metadata whenever the UMEM has metadata space, even if the descriptor does not set XDP_TX_METADATA. Pass descriptor options through the metadata helpers and ignore metadata unless the option is set. This does not fix the existing per-WQE metadata handling for mlx5 MPWQEs. Only the descriptor that starts a session passes through xsk_tx_metadata_request() and configures offload state shared by the batch. Metadata on descriptors joining an open session is therefore not validated and does not configure its requested offloads. In addition, a non-NULL metadata pointer from such a descriptor is treated as a timestamp completion request even when XDP_TXMD_FLAGS_TIMESTAMP is not set, so its metadata union can be overwritten with an unrequested timestamp. Fixing mixed metadata states within one MPWQE requires a separate change.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/8ba0d143e471c85f8a116707c0b42bf046b0a7b3
• https://git.kernel.org/stable/c/53a5b262d706b572840cbe8feae392538077ee19
• https://git.kernel.org/stable/c/bf9387488d6394845076928c6ca5315ce5d84f54
• https://git.kernel.org/stable/c/a6e4b9a6deb9362ef7a0706c70d674e92fe1411a