On Mon, 13 Nov 2023, Harshit Mogalapalli wrote:
> 'attr_name_kobj' is allocated using kzalloc, but on all the error paths
> it is not freed, hence we have a memory leak.
>
> Fix the error path before kobject_init_and_add() by adding kfree().
>
> kobject_put() must be always called after passing the object to
> kobject_init_and_add(). Only the error path which is immediately next
> to kobject_init_and_add() calls kobject_put() and not any other error
> path after it.
>
> Fix the error handling after kobject_init_and_add() by moving the
> kobject_put() into the goto label err_other_attr_init that is already
> used by all the error paths after kobject_init_and_add().
>
> Fixes: a34fc329b189 ("platform/x86: hp-bioscfg: bioscfg")
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Reported-by: Dan Carpenter <error27@xxxxxxxxx>
> Closes: https://lore.kernel.org/r/202309201412.on0VXJGo-lkp@xxxxxxxxx/
> Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>
> ---
> This is based on static analysis, only compile tested.
>
> v3->v4: Add more explicit statement on how we are fixing it, suggested
> by Ilpo
Thanks a lot, this looks fine too now.
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
--
i.
> ---
> drivers/platform/x86/hp/hp-bioscfg/bioscfg.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c
> index a3599498c4e8..6ddca857cc4d 100644
> --- a/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c
> +++ b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c
> @@ -575,77 +575,79 @@ static void release_attributes_data(void)
> /**
> * hp_add_other_attributes() - Initialize HP custom attributes not
> * reported by BIOS and required to support Secure Platform and Sure
> * Start.
> *
> * @attr_type: Custom HP attribute not reported by BIOS
> *
> * Initialize all 2 types of attributes: Platform and Sure Start
> * object. Populates each attribute types respective properties
> * under sysfs files.
> *
> * Returns zero(0) if successful. Otherwise, a negative value.
> */
> static int hp_add_other_attributes(int attr_type)
> {
> struct kobject *attr_name_kobj;
> union acpi_object *obj = NULL;
> int ret;
> char *attr_name;
>
> attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL);
> if (!attr_name_kobj)
> return -ENOMEM;
>
> mutex_lock(&bioscfg_drv.mutex);
>
> /* Check if attribute type is supported */
> switch (attr_type) {
> case HPWMI_SECURE_PLATFORM_TYPE:
> attr_name_kobj->kset = bioscfg_drv.authentication_dir_kset;
> attr_name = SPM_STR;
> break;
>
> case HPWMI_SURE_START_TYPE:
> attr_name_kobj->kset = bioscfg_drv.main_dir_kset;
> attr_name = SURE_START_STR;
> break;
>
> default:
> pr_err("Error: Unknown attr_type: %d\n", attr_type);
> ret = -EINVAL;
> - goto err_other_attr_init;
> + kfree(attr_name_kobj);
> + goto unlock_drv_mutex;
> }
>
> ret = kobject_init_and_add(attr_name_kobj, &attr_name_ktype,
> NULL, "%s", attr_name);
> if (ret) {
> pr_err("Error encountered [%d]\n", ret);
> - kobject_put(attr_name_kobj);
> goto err_other_attr_init;
> }
>
> /* Populate attribute data */
> switch (attr_type) {
> case HPWMI_SECURE_PLATFORM_TYPE:
> ret = hp_populate_secure_platform_data(attr_name_kobj);
> break;
>
> case HPWMI_SURE_START_TYPE:
> ret = hp_populate_sure_start_data(attr_name_kobj);
> break;
>
> default:
> ret = -EINVAL;
> }
>
> if (ret)
> goto err_other_attr_init;
>
> mutex_unlock(&bioscfg_drv.mutex);
> return 0;
>
> err_other_attr_init:
> + kobject_put(attr_name_kobj);
> +unlock_drv_mutex:
> mutex_unlock(&bioscfg_drv.mutex);
> kfree(obj);
> return ret;
> }
>
