From 39de52104dd92bc0548a20201350111dc9317df9 Mon Sep 17 00:00:00 2001 From: Jesper Juhl Date: Sat, 20 Nov 2010 13:36:49 -0800 Subject: [PATCH] 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 Tested-by: Helge Deller Acked-by: Helge Deller Signed-off-by: Dmitry Torokhov --- drivers/input/serio/hil_mlc.c | 5 +++++ drivers/input/serio/hp_sdc_mlc.c | 18 +++++++++--------- 2 files changed, 14 insertions(+), 9 deletions(-) diff --git a/drivers/input/serio/hil_mlc.c b/drivers/input/serio/hil_mlc.c index e5624d8f1709..bfd3865d886b 100644 --- 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 7d2b820ef58d..d50f0678bf47 100644 --- 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) -- 2.39.2