Commit 7bc40aed authored Nov 12, 2020 by Johannes Berg

mac80211: free sta in sta_info_insert_finish() on errors



If sta_info_insert_finish() fails, we currently keep the station
around and free it only in the caller, but there's only one such
caller and it always frees it immediately.

As syzbot found, another consequence of this split is that we can
put things that sleep only into __cleanup_single_sta() and not in
sta_info_free(), but this is the only place that requires such of
sta_info_free() now.

Change this to free the station in sta_info_insert_finish(), in
which case we can still sleep. This will also let us unify the
cleanup code later.

Cc: stable@vger.kernel.org
Fixes: dcd479e1 ("mac80211: always wind down STA state")
Reported-by:  <syzbot+32c6c38c4812d22f2f0b@syzkaller.appspotmail.com>
Reported-by:  <syzbot+4c81fe92e372d26c4246@syzkaller.appspotmail.com>
Reported-by:  <syzbot+6a7fe9faf0d1d61bc24a@syzkaller.appspotmail.com>
Reported-by:  <syzbot+abed06851c5ffe010921@syzkaller.appspotmail.com>
Reported-by:  <syzbot+b7aeb9318541a1c709f1@syzkaller.appspotmail.com>
Reported-by:  <syzbot+d5a9416c6cafe53b5dd0@syzkaller.appspotmail.com>
Link: https://lore.kernel.org/r/20201112112201.ee6b397b9453.I9c31d667a0ea2151441cc64ed6613d36c18a48e0@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>

parent b2911a84

net/mac80211/sta_info.c

+4 −10

Original line number	Diff line number	Diff line
		@@ -705,7 +705,7 @@ static int sta_info_insert_finish(struct sta_info *sta) __acquires(RCU)
		out_drop_sta:
		local->num_sta--;
		synchronize_net();
		__cleanup_single_sta(sta);
		cleanup_single_sta(sta);
		out_err:
		mutex_unlock(&local->sta_mtx);
		kfree(sinfo);
		@@ -724,19 +724,13 @@ int sta_info_insert_rcu(struct sta_info *sta) __acquires(RCU)

		err = sta_info_insert_check(sta);
		if (err) {
		sta_info_free(local, sta);
		mutex_unlock(&local->sta_mtx);
		rcu_read_lock();
		goto out_free;
		return err;
		}

		err = sta_info_insert_finish(sta);
		if (err)
		goto out_free;

		return 0;
		out_free:
		sta_info_free(local, sta);
		return err;
		return sta_info_insert_finish(sta);
		}

		int sta_info_insert(struct sta_info *sta)

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