scsi: scsi_transport_fc: Widen FPIN pname walker counter to u32

Overview

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

scsi: scsi_transport_fc: 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 N_Port 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 pname_count field, and did not bound pname_count by the descriptor body already validated by the TLV walker. A pname_count of 256 therefore wraps the counter and keeps the loop condition true indefinitely.

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

Affected

• Linux >= 3dcfe0de5a9752e646a61f4ce513ac059960c7c3 < 07776b7779c9426982c1ad74aad91bd531593790
• Linux >= 3dcfe0de5a9752e646a61f4ce513ac059960c7c3 < 29f126f09e34a425b376b3646c89aa7cc18b142c
• Linux >= 3dcfe0de5a9752e646a61f4ce513ac059960c7c3 < 163bd704d7515c3df6c2e03bcba93d1db79edbff
• Linux >= 3dcfe0de5a9752e646a61f4ce513ac059960c7c3 < ee57b89e5da9fffbe0d26647e4ff0750dacb9943
• Linux >= 3dcfe0de5a9752e646a61f4ce513ac059960c7c3 < 35461d23744175a78b6280293892cca357c22793
• Linux >= 3dcfe0de5a9752e646a61f4ce513ac059960c7c3 < bdff76dff6ec23d6fe35812fa33e5c4ce2cdb770
• Linux >= 3dcfe0de5a9752e646a61f4ce513ac059960c7c3 < a9a39233ec1fc9f97ea1340a4d09bb7ec2be5153
• Linux 5.11

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.