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: Jesper Juhl <jj@chaosbits.net>
Tested-by: Helge Deller <deller@gmx.de>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

diff --git a/drivers/input/serio/hil_mlc.c b/drivers/input/serio/hil_mlc.c
index e5624d8..bfd3865 100644 (file)
--- a/drivers/input/serio/hil_mlc.c
+++ b/drivers/input/serio/hil_mlc.c
@@ -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;

diff --git a/drivers/input/serio/hp_sdc_mlc.c b/drivers/input/serio/hp_sdc_mlc.c
index 7d2b820..d50f067 100644 (file)
--- a/drivers/input/serio/hp_sdc_mlc.c
+++ b/drivers/input/serio/hp_sdc_mlc.c
@@ -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)
@@ -323,22 +324,21 @@ 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;
+               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");
+               return -EBUSY;
        }
+
        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;
 }
 
 static void __exit hp_sdc_mlc_exit(void)