CVE-2025-38413

/// Technical description

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

virtio-net: xsk: rx: fix the frame's length check

When calling buf_to_xdp, the len argument is the frame data's length

without virtio header's length (vi->hdr_len). We check that len with

xsk_pool_get_rx_frame_size() + vi->hdr_len

to ensure the provided len does not larger than the allocated chunk

size. The additional vi->hdr_len is because in virtnet_add_recvbuf_xsk,

we use part of XDP_PACKET_HEADROOM for virtio header and ask the vhost

to start placing data from

hard_start + XDP_PACKET_HEADROOM - vi->hdr_len

not

hard_start + XDP_PACKET_HEADROOM

But the first buffer has virtio_header, so the maximum frame's length in

the first buffer can only be

xsk_pool_get_rx_frame_size()

not

xsk_pool_get_rx_frame_size() + vi->hdr_len

like in the current check.

This commit adds an additional argument to buf_to_xdp differentiate

between the first buffer and other ones to correctly calculate the maximum

frame's length.

/// 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