Messages in this thread | | | From | Dongliang Mu <> | Date | Fri, 23 Jul 2021 17:13:59 +0800 | Subject | Re: [PATCH] cfg80211: free the object allocated in wiphy_apply_custom_regulatory |
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On Fri, Jul 23, 2021 at 4:37 PM Johannes Berg <johannes@sipsolutions.net> wrote: > > On Fri, 2021-07-23 at 13:09 +0800, Dongliang Mu wrote: > > The commit beee24695157 ("cfg80211: Save the regulatory domain when > > setting custom regulatory") forgets to free the newly allocated regd > > object. > > Not really? It's not forgetting it, it just saves it?
Yes, it saves the regd object in the function wiphy_apply_custom_regulatory.
But its parent function - mac80211_hwsim_new_radio forgets to free this object when the ieee80211_register_hw fails.
> > + new_regd = reg_copy_regd(regd); > + if (IS_ERR(new_regd)) > + return; > + > + tmp = get_wiphy_regdom(wiphy); > + rcu_assign_pointer(wiphy->regd, new_regd); > + rcu_free_regdom(tmp); > > > Fix this by freeing the regd object in the error handling code and > > deletion function - mac80211_hwsim_del_radio. > > This can't be right - the same would affect all other users of that > function, no?
The problem occurs in the error handling code of mac80211_hwsim_new_radio, not wiphy_apply_custom_regulatory. My commit message may be not very clear.
So I think the code in the mac80211_hwsim_del_radio paired with mac80211_hwsim_new_radio should be changed correspondingly. If I miss any problems, please let me know.
I have successfully tested my patch in the syzbot dashboard [1].
[1] https://syzkaller.appspot.com/bug?extid=1638e7c770eef6b6c0d0
> > Perhaps somewhere we have a case where wiphy->regd is leaked, but than > that should be fixed more generally in cfg80211? > > johannes >
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