Re: [PATCH] scsi: ibmvfc: fix OOB access in ibmvfc_discover_targets_done()

[Tyrel Datwyler]

On 3/14/26 10:01 AM, Tyllis Xu wrote:
> A malicious or compromised VIO server can return a num_written value in
> the discover targets MAD response that exceeds max_targets. This value
> is stored directly in vhost->num_targets without validation, and is then
> used as the loop bound in ibmvfc_alloc_targets() to index into disc_buf[],
> which is only allocated for max_targets entries. Indices at or beyond
> max_targets access kernel memory outside the DMA-coherent allocation.
> The out-of-bounds data is subsequently embedded in Implicit Logout and
> PLOGI MADs that are sent back to the VIO server, leaking kernel memory.
> 
> Fix by clamping num_written to max_targets before storing it.
> 
> Fixes: 072b91f9c651 ("[SCSI] ibmvfc: IBM Power Virtual Fibre Channel Adapter Client Driver")
> Reported-by: Yuhao Jiang <danisjiang@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Tyllis Xu <LivelyCarpet87@xxxxxxxxx>

Acked-by: Tyrel Datwyler <tyreld@xxxxxxxxxxxxx>