Commit 61d099ac authored by Tyllis Xu's avatar Tyllis Xu Committed by Martin K. Petersen
Browse files

scsi: ibmvfc: Fix OOB access in ibmvfc_discover_targets_done() 



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: 072b91f9 ("[SCSI] ibmvfc: IBM Power Virtual Fibre Channel Adapter Client Driver")
Reported-by: default avatarYuhao Jiang <danisjiang@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarTyllis Xu <LivelyCarpet87@gmail.com>
Reviewed-by: default avatarDave Marquardt <davemarq@linux.ibm.com>
Acked-by: default avatarTyrel Datwyler <tyreld@linux.ibm.com>
Link: https://patch.msgid.link/20260314170151.548614-1-LivelyCarpet87@gmail.com


Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 7a9f448d

drivers/scsi/ibmvscsi/ibmvfc.c

+2 −1
Original line number Diff line number Diff line
@@ -4966,7 +4966,8 @@ static void ibmvfc_discover_targets_done(struct ibmvfc_event *evt) 
	switch (mad_status) {

	case IBMVFC_MAD_SUCCESS:

		ibmvfc_dbg(vhost, "Discover Targets succeeded\n");

		vhost->num_targets = be32_to_cpu(rsp->num_written);

		vhost->num_targets = min_t(u32, be32_to_cpu(rsp->num_written),

					   max_targets);

		ibmvfc_set_host_action(vhost, IBMVFC_HOST_ACTION_ALLOC_TGTS);

		break;

	case IBMVFC_MAD_FAILED: