CVE-2026-63889: scsi: scsi_transport_fc: Widen FPIN pname walker counter to u32

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

scsi: scsitransportfc: Widen FPIN pname walker counter to u32

An adjacent Fibre Channel fabric actor that can deliver an FPIN ELS frame to an lpfc or qla2xxx Linux initiator can trigger a non-return in the generic FC transport. This is not a local userspace or IP network path; the attacker must be able to inject fabric traffic, for example as a compromised switch or fabric controller, or as a same-zone NPort on a fabric that permits source spoofing.

The Link-Integrity and Peer-Congestion FPIN walkers used a u8 loop counter against the 32-bit on-wire pnamecount field, and did not bound pnamecount by the descriptor body already validated by the TLV walker. A pnamecount of 256 therefore wraps the counter and keeps the loop condition true indefinitely.

Factor the shared pnamelist[] walk into one helper, widen the counter to u32, and clamp pnamecount against the entries that fit in the descriptor body before iterating.