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Commit 39de5210 authored by Jesper Juhl's avatar Jesper Juhl Committed by Dmitry Torokhov
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Input: serio HIL MLC - don't deref null, don't leak and return proper error 



While reviewing various users of kernel memory allocation functions I came
across drivers/input/serio/hil_mlc.c::hil_mlc_register() and noticed that:

 - it calls kzalloc() but fails to check for a NULL return before use.
 - it makes several allocations and if one fails it doesn't free the
   previous ones.
 - It doesn't return -ENOMEM in the failed memory allocation case (it just
   crashes).

This patch corrects all of the above and also reworks the only caller of
this function that I could find
(drivers/input/serio/hp_sdc_mlc.c::hp_sdc_mlc_out()) so that it now checks
the return value of hil_mlc_register() and properly propagates it on
failure and I also restructured the code to remove some labels and goto's
to make it, IMHO nicer to read.

Signed-off-by: default avatarJesper Juhl <jj@chaosbits.net>
Tested-by: default avatarHelge Deller <deller@gmx.de>
Acked-by: default avatarHelge Deller <deller@gmx.de>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent bc95df78

drivers/input/serio/hil_mlc.c

+5 −0
Original line number Diff line number Diff line
@@ -932,6 +932,11 @@ int hil_mlc_register(hil_mlc *mlc) 
		hil_mlc_copy_di_scratch(mlc, i);

		mlc_serio = kzalloc(sizeof(*mlc_serio), GFP_KERNEL);

		mlc->serio[i] = mlc_serio;

		if (!mlc->serio[i]) {

			for (; i >= 0; i--)

				kfree(mlc->serio[i]);

			return -ENOMEM;

		}

		snprintf(mlc_serio->name, sizeof(mlc_serio->name)-1, "HIL_SERIO%d", i);

		snprintf(mlc_serio->phys, sizeof(mlc_serio->phys)-1, "HIL%d", i);

		mlc_serio->id			= hil_mlc_serio_id;

drivers/input/serio/hp_sdc_mlc.c

+9 −9
Original line number Diff line number Diff line
@@ -305,6 +305,7 @@ static void hp_sdc_mlc_out(hil_mlc *mlc) 
static int __init hp_sdc_mlc_init(void)

{

	hil_mlc *mlc = &hp_sdc_mlc;

	int err;



#ifdef __mc68000__

	if (!MACH_IS_HP300)
@@ -323,24 +324,23 @@ static int __init hp_sdc_mlc_init(void) 
	mlc->out = &hp_sdc_mlc_out;

	mlc->priv = &hp_sdc_mlc_priv;



	if (hil_mlc_register(mlc)) {

	err = hil_mlc_register(mlc);

	if (err) {

		printk(KERN_WARNING PREFIX "Failed to register MLC structure with hil_mlc\n");

		goto err0;

		return err;

	}



	if (hp_sdc_request_hil_irq(&hp_sdc_mlc_isr)) {

		printk(KERN_WARNING PREFIX "Request for raw HIL ISR hook denied\n");

		goto err1;

	}

	return 0;

 err1:

		if (hil_mlc_unregister(mlc))

			printk(KERN_ERR PREFIX "Failed to unregister MLC structure with hil_mlc.\n"

				"This is bad.  Could cause an oops.\n");

 err0:

		return -EBUSY;

	}



	return 0;

}



static void __exit hp_sdc_mlc_exit(void)

{

	hil_mlc *mlc = &hp_sdc_mlc;