linux-kernel - [PATCH v4 3/4] platform/x86: hp-bioscfg: Fix error handling in hp_add_other

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Message-ID: <20231113200742.3593548-3-harshit.m.mogalapalli@oracle.com>
Date:   Mon, 13 Nov 2023 12:07:39 -0800
From:   Harshit Mogalapalli <harshit.m.mogalapalli@...cle.com>
To:     Jorge Lopez <jorge.lopez2@...com>,
        Hans de Goede <hdegoede@...hat.com>,
        Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
        Mark Gross <markgross@...nel.org>,
        Thomas Weißschuh <linux@...ssschuh.net>,
        platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     dan.carpenter@...aro.org, kernel-janitors@...r.kernel.org,
        error27@...il.com, vegard.nossum@...cle.com,
        harshit.m.mogalapalli@...cle.com, kernel test robot <lkp@...el.com>
Subject: [PATCH v4 3/4] platform/x86: hp-bioscfg: Fix error handling in hp_add_other_attributes()

'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@...el.com>
Reported-by: Dan Carpenter <error27@...il.com>
Closes: https://lore.kernel.org/r/202309201412.on0VXJGo-lkp@intel.com/
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@...cle.com>
---
This is based on static analysis, only compile tested.

v3->v4: Add more explicit statement on how we are fixing it, suggested
by Ilpo
---
 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;
 }
-- 
2.42.0