Re: [PATCH v3 1/7] livepatch: Fix NULL pointer dereference in klp_find_func()

[Petr Mladek <pmladek@suse.com>]

On Tue 2026-06-23 10:20:38, Miroslav Benes wrote:
> > > Anyway, could you send the fix separately since it is an existing issue,
> > > please?
> > 
> > Does the following change look good to you ?
> > 
> > diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> > index 28d15ba58a26..317a3c866c76 100644
> > --- a/kernel/livepatch/core.c
> > +++ b/kernel/livepatch/core.c
> > @@ -799,9 +799,6 @@ void klp_free_replaced_patches_async(struct
> > klp_patch *new_patch)
> > 
> >  static int klp_init_func(struct klp_object *obj, struct klp_func *func)
> >  {
> > -       if (!func->old_name)
> > -               return -EINVAL;
> > -
> >         /*
> >          * NOPs get the address later. The patched module must be loaded,
> >          * see klp_init_object_loaded().
> > @@ -1107,8 +1104,9 @@ static int __klp_enable_patch(struct klp_patch *patch)
> >   */
> >  int klp_enable_patch(struct klp_patch *patch)
> >  {
> > -       int ret;
> >         struct klp_object *obj;
> > +       struct klp_func *func;
> > +       int ret;
> > 
> >         if (!patch || !patch->mod || !patch->objs)
> >                 return -EINVAL;
> > @@ -1116,9 +1114,12 @@ int klp_enable_patch(struct klp_patch *patch)
> >         klp_for_each_object_static(patch, obj) {
> >                 if (!obj->funcs)
> >                         return -EINVAL;
> > +               klp_for_each_func_static(obj, func) {
> > +                       if (!func->old_name)
> > +                               return -EINVAL;
> > +               }
> >         }
> > 
> > -
> >         if (!is_livepatch_module(patch->mod)) {
> >                 pr_err("module %s is not marked as a livepatch module\n",
> >                        patch->mod->name);
> 
> If you wrap it into klp_check_patch() which Petr proposed alongside 
> with all the checks at the beginning of klp_enable_patch() up to 
> is_livepatch_module(), then yes, I think.

+1

Best Regards,
Petr