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

commit dd4f730 upstream.

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 <[email protected]>
Fixes: a2ff95e ("ACPI: platform: Add platform profile support")
Reported-by: John Rowley <[email protected]>
Closes: ClangBuiltLinux/linux#2047
Tested-by: John Rowley <[email protected]>
Reviewed-by: Sami Tolvanen <[email protected]>
Signed-off-by: Nathan Chancellor <[email protected]>
Acked-by: Greg Kroah-Hartman <[email protected]>
Reviewed-by: Mark Pearson <[email protected]>
Tested-by: Mark Pearson <[email protected]>
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 <[email protected]>
[nathan: Fix conflicts in older stable branches]
Signed-off-by: Nathan Chancellor <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: nathanchance

drivers/acpi/platform_profile.c

@@ -22,8 +22,8 @@ static const char * const profile_names[] = {
 };
 static_assert(ARRAY_SIZE(profile_names) == PLATFORM_PROFILE_LAST);
 
-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)
 {
 	int len = 0;
@@ -49,8 +49,8 @@ static ssize_t platform_profile_choices_show(struct device *dev,
 	return len;
 }
 
-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_BALANCED;
@@ -77,8 +77,8 @@ static ssize_t platform_profile_show(struct device *dev,
 	return sysfs_emit(buf, "%s\n", profile_names[profile]);
 }
 
-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)
 {
 	int err, i;
@@ -115,12 +115,12 @@ 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
 };