CVE-2021-47183

/// Technical description

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

scsi: lpfc: Fix link down processing to address NULL pointer dereference

If an FC link down transition while PLOGIs are outstanding to fabric well

known addresses, outstanding ABTS requests may result in a NULL pointer

dereference. Driver unload requests may hang with repeated "2878" log

messages.

The Link down processing results in ABTS requests for outstanding ELS

requests. The Abort WQEs are sent for the ELSs before the driver had set

the link state to down. Thus the driver is sending the Abort with the

expectation that an ABTS will be sent on the wire. The Abort request is

stalled waiting for the link to come up. In some conditions the driver may

auto-complete the ELSs thus if the link does come up, the Abort completions

may reference an invalid structure.

Fix by ensuring that Abort set the flag to avoid link traffic if issued due

to conditions where the link failed.

/// 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