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 the same type as the callbacks in 'struct kobj_attribute'.
However, the platform_profile sysfs functions have the type of the
->show() and ->store() callbacks in 'struct device_attribute', which
results 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)
This happens to work because the layout of 'struct kobj_attribute' and
'struct device_attribute' are the same, so the container_of() cast
happens to allow the callbacks to still work.
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: stable@xxxxxxxxxxxxxxx
Fixes: a2ff95e018f1 ("ACPI: platform: Add platform profile support")
Reported-by: John Rowley <lkml@xxxxxxxxxxxxx>
Closes: https://github.com/ClangBuiltLinux/linux/issues/2047
Tested-by: John Rowley <lkml@xxxxxxxxxxxxx>
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
---
drivers/acpi/platform_profile.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c
index d2f7fd7743a1..11278f785526 100644
--- a/drivers/acpi/platform_profile.c
+++ b/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
};
---
base-commit: 47ac09b91befbb6a235ab620c32af719f8208399
change-id: 20240819-acpi-platform_profile-fix-cfi-violation-de278753bd5f
Best regards,
--
Nathan Chancellor <nathan@xxxxxxxxxx>
