[PATCH 5.15 139/279] platform/x86: think-lmi: Abort probe on analyze failure

Greg Kroah-Hartman
2021-11-24T13:53:33Z

From: Alex Williamson <alex.williamson@redhat.com>

[ Upstream commit 812fcc609502096e98cc3918a4b807722dba8fd9 ]

A Lenovo ThinkStation S20 (4157CTO BIOS 60KT41AUS) fails to boot on
recent kernels including the think-lmi driver, due to the fact that
errors returned by the tlmi_analyze() function are ignored by
tlmi_probe(), where tlmi_sysfs_init() is called unconditionally.
This results in making use of an array of already freed, non-null
pointers and other uninitialized globals, causing all sorts of nasty
kobject and memory faults.

Make use of the analyze function return value, free a couple leaked
allocations, and remove the settings_count field, which is incremented
but never consumed.

Fixes: a40cd7ef22fb ("platform/x86: think-lmi: Add WMI interface support on Lenovo platforms")
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Mark Gross <markgross@kernel.org>
Reviewed-by: Mark Pearson <markpearson@lenovo.com>
Link: https://lore.kernel.org/r/163639463588.1330483.15850167112490200219.stgit@omen
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/platform/x86/think-lmi.c | 13 ++++++++++---
drivers/platform/x86/think-lmi.h | 1 -
2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
index 9472aae72df29..c4d9c45350f7c 100644
--- a/drivers/platform/x86/think-lmi.c
+++ b/drivers/platform/x86/think-lmi.c
@@ -888,8 +888,10 @@ static int tlmi_analyze(void)
break;
if (!item)
break;
- if (!*item)
+ if (!*item) {
+ kfree(item);
continue;
+ }

/* It is not allowed to have '/' for file name. Convert it into '\'. */
strreplace(item, '/', '\\');
@@ -902,6 +904,7 @@ static int tlmi_analyze(void)
setting = kzalloc(sizeof(*setting), GFP_KERNEL);
if (!setting) {
ret = -ENOMEM;
+ kfree(item);
goto fail_clear_attr;
}
setting->index = i;
@@ -916,7 +919,6 @@ static int tlmi_analyze(void)
}
kobject_init(&setting->kobj, &tlmi_attr_setting_ktype);
tlmi_priv.setting[i] = setting;
- tlmi_priv.settings_count++;
kfree(item);
}

@@ -983,7 +985,12 @@ static void tlmi_remove(struct wmi_device *wdev)

static int tlmi_probe(struct wmi_device *wdev, const void *context)
{
- tlmi_analyze();
+ int ret;
+
+ ret = tlmi_analyze();
+ if (ret)
+ return ret;
+
return tlmi_sysfs_init();
}

diff --git a/drivers/platform/x86/think-lmi.h b/drivers/platform/x86/think-lmi.h
index f8e26823075fd..2ce5086a5af27 100644
--- a/drivers/platform/x86/think-lmi.h
+++ b/drivers/platform/x86/think-lmi.h
@@ -55,7 +55,6 @@ struct tlmi_attr_setting {
struct think_lmi {
struct wmi_device *wmi_device;

- int settings_count;
bool can_set_bios_settings;
bool can_get_bios_selections;
bool can_set_bios_password;
--
2.33.0