ACPI: platform-profile: Fix CFI violation when accessing sysfs files

JIRA: https://issues.redhat.com/browse/RHEL-89362

commit dd4f730
Author: Nathan Chancellor <nathan@kernel.org>
Date: Tue, 18 Feb 2025 18:59:39 +0000

When an attribute group is created with sysfs_create_group(), the
->sysfs_ops() callback is set to kobj_sysfs_ops, which sets the ->show()
and ->store() callbacks to kobj_attr_show() and kobj_attr_store()
respectively. These functions use container_of() to get the respective
callback from the passed attribute, meaning that these callbacks need to
be of the same type as the callbacks in 'struct kobj_attribute'.

However, ->show() and ->store() in the platform_profile driver are
defined for struct device_attribute with the help of DEVICE_ATTR_RO()
and DEVICE_ATTR_RW(), which results in a CFI violation when accessing
platform_profile or platform_profile_choices under /sys/firmware/acpi
because the types do not match:

  CFI failure at kobj_attr_show+0x19/0x30 (target: platform_profile_choices_show+0x0/0x140; expected type: 0x7a69590c)

There is no functional issue from the type mismatch because the layout
of 'struct kobj_attribute' and 'struct device_attribute' are the same,
so the container_of() cast does not break anything aside from CFI.

Change the type of platform_profile_choices_show() and
platform_profile_{show,store}() to match the callbacks in
'struct kobj_attribute' and update the attribute variables to
match, which resolves the CFI violation.

Cc: All applicable <stable@vger.kernel.org>
Fixes: a2ff95e ("ACPI: platform: Add platform profile support")
Reported-by: John Rowley <lkml@johnrowley.me>
Closes: ClangBuiltLinux/linux#2047
Tested-by: John Rowley <lkml@johnrowley.me>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Tested-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Link: https://patch.msgid.link/20250210-acpi-platform_profile-fix-cfi-violation-v3-1-ed9e9901c33a@kernel.org
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Mark Langsdorf <mlangsdo@redhat.com>

Author: mlangsdorf

drivers/acpi/platform_profile.c

@@ -289,14 +289,14 @@ static int _remove_hidden_choices(struct device *dev, void *arg)
 
 /**
  * platform_profile_choices_show - Show the available profile choices for legacy sysfs interface
- * @dev: The device
+ * @kobj: The kobject
  * @attr: The attribute
  * @buf: The buffer to write to
  *
  * Return: The number of bytes written
  */
-static ssize_t platform_profile_choices_show(struct device *dev,
-					     struct device_attribute *attr,
+static ssize_t platform_profile_choices_show(struct kobject *kobj,
+					     struct kobj_attribute *attr,
 					     char *buf)
 {
 	struct aggregate_choices_data data = {
@@ -371,14 +371,14 @@ static int _store_and_notify(struct device *dev, void *data)
 
 /**
  * platform_profile_show - Show the current profile for legacy sysfs interface
- * @dev: The device
+ * @kobj: The kobject
  * @attr: The attribute
  * @buf: The buffer to write to
  *
  * Return: The number of bytes written
  */
-static ssize_t platform_profile_show(struct device *dev,
-				     struct device_attribute *attr,
+static ssize_t platform_profile_show(struct kobject *kobj,
+				     struct kobj_attribute *attr,
 				     char *buf)
 {
 	enum platform_profile_option profile = PLATFORM_PROFILE_LAST;
@@ -400,15 +400,15 @@ static ssize_t platform_profile_show(struct device *dev,
 
 /**
  * platform_profile_store - Set the profile for legacy sysfs interface
- * @dev: The device
+ * @kobj: The kobject
  * @attr: The attribute
  * @buf: The buffer to read from
  * @count: The number of bytes to read
  *
  * Return: The number of bytes read
  */
-static ssize_t platform_profile_store(struct device *dev,
-				      struct device_attribute *attr,
+static ssize_t platform_profile_store(struct kobject *kobj,
+				      struct kobj_attribute *attr,
 				      const char *buf, size_t count)
 {
 	struct aggregate_choices_data data = {
@@ -442,12 +442,12 @@ static ssize_t platform_profile_store(struct device *dev,
 	return count;
 }
 
-static DEVICE_ATTR_RO(platform_profile_choices);
-static DEVICE_ATTR_RW(platform_profile);
+static struct kobj_attribute attr_platform_profile_choices = __ATTR_RO(platform_profile_choices);
+static struct kobj_attribute attr_platform_profile = __ATTR_RW(platform_profile);
 
 static struct attribute *platform_profile_attrs[] = {
-	&dev_attr_platform_profile_choices.attr,
-	&dev_attr_platform_profile.attr,
+	&attr_platform_profile_choices.attr,
+	&attr_platform_profile.attr,
 	NULL
 };