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Commit 240b4cc8 authored by Jan Kara's avatar Jan Kara Committed by Martin K. Petersen
Browse files

scsi: vmw_pscsi: Fix use-after-free in pvscsi_queue_lck() 



Once we unlock adapter->hw_lock in pvscsi_queue_lck() nothing prevents just
queued scsi_cmnd from completing and freeing the request. Thus cmd->cmnd[0]
dereference can dereference already freed request leading to kernel crashes
or other issues (which one of our customers observed). Store cmd->cmnd[0]
in a local variable before unlocking adapter->hw_lock to fix the issue.

CC: <stable@vger.kernel.org>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarEwan D. Milne <emilne@redhat.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 5589b08e

drivers/scsi/vmw_pvscsi.c

+4 −2
Original line number Diff line number Diff line
@@ -763,6 +763,7 @@ static int pvscsi_queue_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd 
	struct pvscsi_adapter *adapter = shost_priv(host);

	struct pvscsi_ctx *ctx;

	unsigned long flags;

	unsigned char op;



	spin_lock_irqsave(&adapter->hw_lock, flags);
@@ -775,13 +776,14 @@ static int pvscsi_queue_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd 
	}



	cmd->scsi_done = done;

	op = cmd->cmnd[0];



	dev_dbg(&cmd->device->sdev_gendev,

		"queued cmd %p, ctx %p, op=%x\n", cmd, ctx, cmd->cmnd[0]);

		"queued cmd %p, ctx %p, op=%x\n", cmd, ctx, op);



	spin_unlock_irqrestore(&adapter->hw_lock, flags);



	pvscsi_kick_io(adapter, cmd->cmnd[0]);

	pvscsi_kick_io(adapter, op);



	return 0;

}