High [CVE-2026-80693] bound interrupt-vector register fill to the allocated array

In the Linux kernel, the following vulnerability has been resolved: idpf: bound interrupt-vector register fill to the allocated array idpf_get_reg_intr_vecs() fills the caller-allocated reg_vals[] array from the VIRTCHNL2_OP_ALLOC_VECTORS reply in adapter->req_vec_chunks, bounding its inner loop only by the per-chunk num_vectors.

The array is sized separately: idpf_intr_reg_init() allocates kzalloc_objs(struct idpf_vec_regs, total_vecs) from caps.num_allocated_vectors and only checks the returned count after the fill.

The sum of per-chunk num_vectors is never reconciled against total_vecs, so a reply with a small num_allocated_vectors but chunks summing higher writes past the end of reg_vals[].

Impact: a control plane (a PF or hypervisor device model) that returns a VIRTCHNL2_OP_ALLOC_VECTORS reply whose per-chunk num_vectors sum exceeds num_allocated_vectors writes struct idpf_vec_regs entries past the end of the reg_vals kmalloc allocation (KASAN slab-out-of-bounds write).

Bound the fill loop to the array capacity passed in by the callers, mirroring the sibling idpf_vport_get_q_reg(). The existing num_regs < num_vecs check then rejects an undersized reply without the out-of-bounds write happening first.

Affected products named by the advisory: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat package: kernel-rt.