CVE-2024-43816

What it actually does

Incorrect endian handling in lpfc_prep_embed_io causes memcpy to use a little-endian sge_len value directly on big-endian systems, resulting in out-of-bounds pointer dereference and memory corruption when FCP targets are zoned.

Why it matters to the business

Big-endian systems using the lpfc driver can experience unexpected kernel crashes during storage I/O with zoned FCP targets, leading to downtime and potential data access disruption.

How an attack unfolds

An attacker with the ability to influence FCP target zoning on a vulnerable big-endian Linux system triggers lpfc_prep_embed_io during normal storage operations; the missing le32_to_cpu conversion causes the memcpy to reference invalid memory lengths and crash the kernel.

How to fix it

Update the lpfc driver to the revision that redefines the sgl pointer as struct sli4_sge_le and applies proper le32_to_cpu conversions; apply the corresponding mainline or distribution kernel update containing commit 532b3c416420c2d30be9c9757b8c001a8e3cb49e where available.

How to confirm the fix worked

Inspect the lpfc driver source for the struct sli4_sge_le change and le32_to_cpu usage around the memcpy call; confirm the updated kernel boots without the described crash on big-endian hardware with zoned FCP targets.

Typical attack path

1. Identify big-endian Linux hosts running the vulnerable lpfc driver
2. Configure or trigger FCP target zoning that exercises embedded I/O paths
3. Initiate storage commands that invoke lpfc_prep_embed_io
4. Trigger the memcpy with the unconverted little-endian length value
5. Cause out-of-bounds access resulting in kernel panic

How to detect it

Search kernel logs and crash dumps for lpfc_prep_embed_io call stacks or memory faults on big-endian systems; correlate with FCP zoning events or storage I/O activity around the time of the panic.

What your security team should do

• Apply the endian-fix patch immediately on big-endian architectures
• Prioritize testing and deployment on production systems that use lpfc with FCP zoning
• Monitor kernel logs for lpfc-related oops or panics on affected hardware
• Review storage zoning configurations to reduce unnecessary trigger conditions until patched