IR: ene_ir: problems in unwinding on probe

There were a couple issues here. If the allocation failed for "dev" then it would lead to a NULL dereference. If request_irq() or request_region() failed it would release the irq and the region even though they were not successfully aquired.

Signed-off-by Dan Carpenter <[email protected]>

drivers/media/IR/ene_ir.c +22 -17

index 5447750..8e5e964 100644
@@ -781,21 +781,24 @@ static int ene_probe(struct pnp_dev *pnp_dev, const struct pnp_device_id *id)
 
 	/* allocate memory */
 	input_dev = input_allocate_device();
+	if (!input_dev)
+		goto err_out;
 	ir_props = kzalloc(sizeof(struct ir_dev_props), GFP_KERNEL);
+	if (!ir_props)
+		goto err_input_dev;
 	dev = kzalloc(sizeof(struct ene_device), GFP_KERNEL);
-
-	if (!input_dev || !ir_props || !dev)
-		goto error;
+	if (!dev)
+		goto err_ir_props;
 
 	/* validate resources */
 	error = -ENODEV;
 
 	if (!pnp_port_valid(pnp_dev, 0) ||
 	    pnp_port_len(pnp_dev, 0) < ENE_MAX_IO)
-		goto error;
+		goto err_dev;
 
 	if (!pnp_irq_valid(pnp_dev, 0))
-		goto error;
+		goto err_dev;
 
 	dev->hw_io = pnp_port_start(pnp_dev, 0);
 	dev->irq = pnp_irq(pnp_dev, 0);

@@ -804,11 +807,11 @@ static int ene_probe(struct pnp_dev *pnp_dev, const struct pnp_device_id *id)
 	/* claim the resources */
 	error = -EBUSY;
 	if (!request_region(dev->hw_io, ENE_MAX_IO, ENE_DRIVER_NAME))
-		goto error;
+		goto err_dev;
 
 	if (request_irq(dev->irq, ene_isr,
 			IRQF_SHARED, ENE_DRIVER_NAME, (void *)dev))
-		goto error;
+		goto err_region;
 
 	pnp_set_drvdata(pnp_dev, dev);
 	dev->pnp_dev = pnp_dev;

@@ -816,7 +819,7 @@ static int ene_probe(struct pnp_dev *pnp_dev, const struct pnp_device_id *id)
 	/* detect hardware version and features */
 	error = ene_hw_detect(dev);
 	if (error)
-		goto error;
+		goto err_irq;
 
 	ene_setup_settings(dev);
 

@@ -889,20 +892,22 @@ static int ene_probe(struct pnp_dev *pnp_dev, const struct pnp_device_id *id)
 	error = -ENODEV;
 	if (ir_input_register(input_dev, RC_MAP_RC6_MCE, ir_props,
 							ENE_DRIVER_NAME))
-		goto error;
-
+		goto err_irq;
 
 	ene_printk(KERN_NOTICE, "driver has been succesfully loaded\n");
 	return 0;
-error:
-	if (dev->irq)
-		free_irq(dev->irq, dev);
-	if (dev->hw_io)
-		release_region(dev->hw_io, ENE_MAX_IO);
 
-	input_free_device(input_dev);
-	kfree(ir_props);
+err_irq:
+	free_irq(dev->irq, dev);
+err_region:
+	release_region(dev->hw_io, ENE_MAX_IO);
+err_dev:
 	kfree(dev);
+err_ir_props:
+	kfree(ir_props);
+err_input_dev:
+	input_free_device(input_dev);
+err_out:
 	return error;
 }
 

Quoted 5 lines · Dan Carpenter

There were a couple issues here. If the allocation failed for "dev" then it would lead to a NULL dereference. If request_irq() or request_region() failed it would release the irq and the region even though they were not successfully aquired.

Quoted 1 line

Signed-off-by Dan Carpenter <[email protected]>

I don't think this is needed.
I just alloc all the stuff, and if one of allocations fail, I free them all. {k}free on NULL pointer is perfectly legal.

Same about IO and IRQ.
IRQ0 and IO 0 isn't valid, and I do test that in error path.

Quoted 6 lines · Maxim Levitsky

Quoted 5 lines · Dan Carpenter

There were a couple issues here. If the allocation failed for "dev" then it would lead to a NULL dereference. If request_irq() or request_region() failed it would release the irq and the region even though they were not successfully aquired.

Quoted 10 lines

Quoted 1 line

Signed-off-by Dan Carpenter <[email protected]>

I don't think this is needed.
I just alloc all the stuff, and if one of allocations fail, I free them all. {k}free on NULL pointer is perfectly legal.

Same about IO and IRQ.
IRQ0 and IO 0 isn't valid, and I do test that in error path.

Here is the original code:

Here is where we set "dev".

   785          dev = kzalloc(sizeof(struct ene_device), GFP_KERNEL);
   786  
   787          if (!input_dev || !ir_props || !dev)
   788                  goto error;

	[snip]

Here is where we set the IO and IRQ:

   800          dev->hw_io = pnp_port_start(pnp_dev, 0);
   801          dev->irq = pnp_irq(pnp_dev, 0);

	[snip]

Here is where the request_region() and request_irq() are.

   806          if (!request_region(dev->hw_io, ENE_MAX_IO, ENE_DRIVER_NAME))
   807                  goto error;
   808  
   809          if (request_irq(dev->irq, ene_isr, 
   810                          IRQF_SHARED, ENE_DRIVER_NAME, (void *)dev))
   811                  goto error;

	[snip]

Here is the error label:

   897  error:
   898          if (dev->irq)
		    ^^^^^^^^

	Oops!  The allocation of dev failed and this is a NULL
	dereference.

   899                  free_irq(dev->irq, dev);

	Oops!  Request region failed and dev->irq is non-zero but
	request_irq() hasn't been called.

   900          if (dev->hw_io)
   901                  release_region(dev->hw_io, ENE_MAX_IO);

	Oops! dev->hw_io is non-zero but request_region() failed and so
	we just released someone else's region.