Hi Dan,
On Fri, 20 Mar 2020 at 13:23, Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
>
> If the "handles" allocation or the copy_from_user() fails then we leak
> "objs". It's supposed to be freed in panfrost_job_cleanup().
>
> Fixes: c117aa4d8701 ("drm: Add a drm_gem_objects_lookup helper")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
> drivers/gpu/drm/drm_gem.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> index a9e4a610445a..f28724f2eb69 100644
> --- a/drivers/gpu/drm/drm_gem.c
> +++ b/drivers/gpu/drm/drm_gem.c
> @@ -710,6 +710,8 @@ int drm_gem_objects_lookup(struct drm_file *filp, void __user *bo_handles,
> if (!objs)
> return -ENOMEM;
>
> + *objs_out = objs;
> +
> handles = kvmalloc_array(count, sizeof(u32), GFP_KERNEL);
> if (!handles) {
> ret = -ENOMEM;
> @@ -723,8 +725,6 @@ int drm_gem_objects_lookup(struct drm_file *filp, void __user *bo_handles,
> }
>
> ret = objects_lookup(filp, handles, count, objs);
> - *objs_out = objs;
> -
> out:
> kvfree(handles);
> return ret;
It seems that this will return error to the caller, mangle the output
pointer and effectively still leak the objs.
Better option IMHO is to:
- move the __user/copy_from_user into the caller
Removes a silly kvmalloc_array(1,...) in ~90+ users and drops the "out" label.
Extra bonus, this is the only instance in drm_gem with __user -
consistency is nice.
- add "err" or similar label, where the objs is freed before returning an error.
-Emil
