CVE-2021-47045: 
Linux Kernel vulnerability analysis and mitigation

CVE-2021-47045 is a vulnerability in the scsi/lpfcIt subsystem of the Linux kernel. The vulnerability was discovered when it was found possible to call lpfc_issue_els_plogi() passing a did argument for which no matching ndlp is found, resulting in a null pointer dereference when lpfc_prep_els_iocb() is called with a NULL pointer to a lpfc_nodelist structure (Red Hat Portal).

The vulnerability exists in the Linux kernel's SCSI subsystem, specifically in the lpfc driver. The issue occurs when lpfc_issue_els_plogi() is called with a device ID (did) that has no corresponding node in the system. This leads to lpfc_prep_els_iocb() being called with a null pointer to the lpfc_nodelist structure. The vulnerability has been assigned a CVSS v3.1 score of 4.4, indicating moderate severity (Red Hat Portal).

When exploited, this vulnerability can result in a null pointer dereference, which typically leads to a system crash or denial of service condition. The impact is limited to availability, with no direct effects on confidentiality or integrity of the system (Red Hat Portal).

The vulnerability requires local access to the system and high privileges to exploit. The attack complexity is considered low, but the requirement for high privileges reduces the overall exploitability of the vulnerability (Red Hat Portal).

The vulnerability has been fixed by adding a check for null ndlp and returning an error status if no valid ndlp is found. The fix also includes updates to comments regarding ndlp reference counting (Kernel Git).