From: Nathan Chancellor Date: Fri, 13 May 2022 07:51:36 +0000 (+0100) Subject: drm/i915: Fix CFI violation with show_dynamic_id() X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=18fb42db05a0b93ab5dd5eab5315e50eaa3ca620;p=linux.git drm/i915: Fix CFI violation with show_dynamic_id() When an attribute group is created with sysfs_create_group(), the ->sysfs_ops() callback is set to kobj_sysfs_ops, which sets the ->show() callback to kobj_attr_show(). kobj_attr_show() uses container_of() to get the ->show() callback from the attribute it was passed, meaning the ->show() callback needs to be the same type as the ->show() callback in 'struct kobj_attribute'. However, show_dynamic_id() has the type of the ->show() callback in 'struct device_attribute', which causes a CFI violation when opening the 'id' sysfs node under drm/card0/metrics. 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 ->show() callback to still work. Change the type of show_dynamic_id() to match the ->show() callback in 'struct kobj_attributes' and update the type of sysfs_metric_id to match, which resolves the CFI violation. Fixes: f89823c21224 ("drm/i915/perf: Implement I915_PERF_ADD/REMOVE_CONFIG interface") Signed-off-by: Nathan Chancellor Reviewed-by: Kees Cook Reviewed-by: Sami Tolvanen Signed-off-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20220513075136.1027007-1-tvrtko.ursulin@linux.intel.com --- diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c index 0a9c3fcc09b1e..1577ab6754db1 100644 --- a/drivers/gpu/drm/i915/i915_perf.c +++ b/drivers/gpu/drm/i915/i915_perf.c @@ -4050,8 +4050,8 @@ addr_err: return ERR_PTR(err); } -static ssize_t show_dynamic_id(struct device *dev, - struct device_attribute *attr, +static ssize_t show_dynamic_id(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) { struct i915_oa_config *oa_config = diff --git a/drivers/gpu/drm/i915/i915_perf_types.h b/drivers/gpu/drm/i915/i915_perf_types.h index 473a3c0544bb8..05cb9a335a971 100644 --- a/drivers/gpu/drm/i915/i915_perf_types.h +++ b/drivers/gpu/drm/i915/i915_perf_types.h @@ -55,7 +55,7 @@ struct i915_oa_config { struct attribute_group sysfs_metric; struct attribute *attrs[2]; - struct device_attribute sysfs_metric_id; + struct kobj_attribute sysfs_metric_id; struct kref ref; struct rcu_head rcu;