2023-09-23 22:00:47

by Armin Wolf

Subject: [PATCH] platform/x86: think-lmi: Fix reference leak

If a duplicate attribute is found using kset_find_obj(), a reference
to that attribute is returned which needs to be disposed accordingly
using kobject_put(). Move the setting name validation into a separate
function to allow for this change without having to duplicate the
cleanup code for this setting.
As a side note, a very similar bug was fixed in
commit 7295a996fdab ("platform/x86: dell-sysman: Fix reference leak"),
so it seems that the bug was copied from that driver.

Compile-tested only.

Fixes: 1bcad8e510b2 ("platform/x86: think-lmi: Fix issues with duplicate attributes")
Signed-off-by: Armin Wolf <[email protected]>
---
drivers/platform/x86/think-lmi.c | 24 ++++++++++++++++++++----
1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
index 4be6f28d4600..3a396b763c49 100644
--- a/drivers/platform/x86/think-lmi.c
+++ b/drivers/platform/x86/think-lmi.c
@@ -1344,6 +1344,24 @@ static void tlmi_release_attr(void)
kset_unregister(tlmi_priv.authentication_kset);
}

+static int tlmi_validate_setting_name(struct kset *attribute_kset, char *name)
+{
+ struct kobject *duplicate;
+
+ if (!strcmp(name, "Reserved"))
+ return -EINVAL;
+
+ duplicate = kset_find_obj(attribute_kset, name);
+ if (duplicate) {
+ pr_debug("Duplicate attribute name found - %s\n", name);
+ /* kset_find_obj() returns a reference */
+ kobject_put(duplicate);
+ return -EBUSY;
+ }
+
+ return 0;
+}
+
static int tlmi_sysfs_init(void)
{
int i, ret;
@@ -1372,10 +1390,8 @@ static int tlmi_sysfs_init(void)
continue;

/* check for duplicate or reserved values */
- if (kset_find_obj(tlmi_priv.attribute_kset, tlmi_priv.setting[i]->display_name) ||
- !strcmp(tlmi_priv.setting[i]->display_name, "Reserved")) {
- pr_debug("duplicate or reserved attribute name found - %s\n",
- tlmi_priv.setting[i]->display_name);
+ if (tlmi_validate_setting_name(tlmi_priv.attribute_kset,
+ tlmi_priv.setting[i]->display_name) < 0) {
kfree(tlmi_priv.setting[i]->possible_values);
kfree(tlmi_priv.setting[i]);
tlmi_priv.setting[i] = NULL;
--
2.39.2

2023-09-25 14:10:36

by Ilpo Järvinen

Subject: Re: [PATCH] platform/x86: think-lmi: Fix reference leak

On Sat, 23 Sep 2023, Armin Wolf wrote:

> If a duplicate attribute is found using kset_find_obj(), a reference
> to that attribute is returned which needs to be disposed accordingly
> using kobject_put(). Move the setting name validation into a separate
> function to allow for this change without having to duplicate the
> cleanup code for this setting.
> As a side note, a very similar bug was fixed in
> commit 7295a996fdab ("platform/x86: dell-sysman: Fix reference leak"),
> so it seems that the bug was copied from that driver.
>
> Compile-tested only.
>
> Fixes: 1bcad8e510b2 ("platform/x86: think-lmi: Fix issues with duplicate attributes")
> Signed-off-by: Armin Wolf <[email protected]>
> ---
> drivers/platform/x86/think-lmi.c | 24 ++++++++++++++++++++----
> 1 file changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
> index 4be6f28d4600..3a396b763c49 100644
> --- a/drivers/platform/x86/think-lmi.c
> +++ b/drivers/platform/x86/think-lmi.c
> @@ -1344,6 +1344,24 @@ static void tlmi_release_attr(void)
> kset_unregister(tlmi_priv.authentication_kset);
> }
>
> +static int tlmi_validate_setting_name(struct kset *attribute_kset, char *name)
> +{
> + struct kobject *duplicate;
> +
> + if (!strcmp(name, "Reserved"))
> + return -EINVAL;
> +
> + duplicate = kset_find_obj(attribute_kset, name);
> + if (duplicate) {
> + pr_debug("Duplicate attribute name found - %s\n", name);
> + /* kset_find_obj() returns a reference */
> + kobject_put(duplicate);
> + return -EBUSY;
> + }
> +
> + return 0;
> +}
> +
> static int tlmi_sysfs_init(void)
> {
> int i, ret;
> @@ -1372,10 +1390,8 @@ static int tlmi_sysfs_init(void)
> continue;
>
> /* check for duplicate or reserved values */
> - if (kset_find_obj(tlmi_priv.attribute_kset, tlmi_priv.setting[i]->display_name) ||
> - !strcmp(tlmi_priv.setting[i]->display_name, "Reserved")) {
> - pr_debug("duplicate or reserved attribute name found - %s\n",
> - tlmi_priv.setting[i]->display_name);
> + if (tlmi_validate_setting_name(tlmi_priv.attribute_kset,
> + tlmi_priv.setting[i]->display_name) < 0) {
> kfree(tlmi_priv.setting[i]->possible_values);
> kfree(tlmi_priv.setting[i]);
> tlmi_priv.setting[i] = NULL;

Reviewed-by: Ilpo J?rvinen <[email protected]>

There seem to be two more of these in hp-bioscfg.

--
i.

2023-09-26 08:52:27

by Mark Pearson

Subject: Re: [External] [PATCH] platform/x86: think-lmi: Fix reference leak

Thanks Armin,

On 9/23/23 16:41, Armin Wolf wrote:
> If a duplicate attribute is found using kset_find_obj(), a reference
> to that attribute is returned which needs to be disposed accordingly
> using kobject_put(). Move the setting name validation into a separate
> function to allow for this change without having to duplicate the
> cleanup code for this setting.
> As a side note, a very similar bug was fixed in
> commit 7295a996fdab ("platform/x86: dell-sysman: Fix reference leak"),
> so it seems that the bug was copied from that driver.
>
> Compile-tested only.
>
> Fixes: 1bcad8e510b2 ("platform/x86: think-lmi: Fix issues with duplicate attributes")
> Signed-off-by: Armin Wolf <[email protected]>
> ---
> drivers/platform/x86/think-lmi.c | 24 ++++++++++++++++++++----
> 1 file changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
> index 4be6f28d4600..3a396b763c49 100644
> --- a/drivers/platform/x86/think-lmi.c
> +++ b/drivers/platform/x86/think-lmi.c
> @@ -1344,6 +1344,24 @@ static void tlmi_release_attr(void)
> kset_unregister(tlmi_priv.authentication_kset);
> }
>
> +static int tlmi_validate_setting_name(struct kset *attribute_kset, char *name)
> +{
> + struct kobject *duplicate;
> +
> + if (!strcmp(name, "Reserved"))
> + return -EINVAL;
> +
> + duplicate = kset_find_obj(attribute_kset, name);
> + if (duplicate) {
> + pr_debug("Duplicate attribute name found - %s\n", name);
> + /* kset_find_obj() returns a reference */
> + kobject_put(duplicate);
> + return -EBUSY;
> + }
> +
> + return 0;
> +}
> +
> static int tlmi_sysfs_init(void)
> {
> int i, ret;
> @@ -1372,10 +1390,8 @@ static int tlmi_sysfs_init(void)
> continue;
>
> /* check for duplicate or reserved values */
> - if (kset_find_obj(tlmi_priv.attribute_kset, tlmi_priv.setting[i]->display_name) ||
> - !strcmp(tlmi_priv.setting[i]->display_name, "Reserved")) {
> - pr_debug("duplicate or reserved attribute name found - %s\n",
> - tlmi_priv.setting[i]->display_name);
> + if (tlmi_validate_setting_name(tlmi_priv.attribute_kset,
> + tlmi_priv.setting[i]->display_name) < 0) {
> kfree(tlmi_priv.setting[i]->possible_values);
> kfree(tlmi_priv.setting[i]);
> tlmi_priv.setting[i] = NULL;
> --
> 2.39.2
>

Reviewed-by: Mark Pearson <[email protected]>

Do you have any reports of our platforms where these are seen? If so I'd like to get it fixed in FW too (and I can get it tested on HW if that helps)

Mark