| Message ID | 20211002145329.3125293-1-anzaki@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Johannes Berg |
| Headers | show |
| Series | mac80211: fix a memory leak where sta_info is not freed | expand |
On Sat, 2021-10-02 at 08:53 -0600, Ahmed Zaki wrote: > > +++ b/net/mac80211/sta_info.c > @@ -640,12 +640,14 @@ static int sta_info_insert_finish(struct sta_info *sta) __acquires(RCU) > > /* check if STA exists already */ > if (sta_info_get_bss(sdata, sta->sta.addr)) { > + sta_info_free(local, sta); > err = -EEXIST; > goto out_err; > } > > sinfo = kzalloc(sizeof(struct station_info), GFP_KERNEL); > if (!sinfo) { > + sta_info_free(local, sta); > err = -ENOMEM; > goto out_err; > } We already have a "out_drop_sta", that calls cleanup_single_sta(), so shouldn't we just add a label there ("out_free_sta") just before cleanup_single_sta() and then we don't need the extra call? johannes
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c index 2b5acb37587f..35fb885040b1 100644 --- a/net/mac80211/sta_info.c +++ b/net/mac80211/sta_info.c @@ -640,12 +640,14 @@ static int sta_info_insert_finish(struct sta_info *sta) __acquires(RCU) /* check if STA exists already */ if (sta_info_get_bss(sdata, sta->sta.addr)) { + sta_info_free(local, sta); err = -EEXIST; goto out_err; } sinfo = kzalloc(sizeof(struct station_info), GFP_KERNEL); if (!sinfo) { + sta_info_free(local, sta); err = -ENOMEM; goto out_err; }
The following is from a system that went OOM due to a memory leak: wlan0: Allocated STA 74:83:c2:64:0b:87 wlan0: Allocated STA 74:83:c2:64:0b:87 wlan0: IBSS finish 74:83:c2:64:0b:87 (---from ieee80211_ibss_add_sta) wlan0: Adding new IBSS station 74:83:c2:64:0b:87 wlan0: moving STA 74:83:c2:64:0b:87 to state 2 wlan0: moving STA 74:83:c2:64:0b:87 to state 3 wlan0: Inserted STA 74:83:c2:64:0b:87 wlan0: IBSS finish 74:83:c2:64:0b:87 (---from ieee80211_ibss_work) wlan0: Adding new IBSS station 74:83:c2:64:0b:87 wlan0: moving STA 74:83:c2:64:0b:87 to state 2 wlan0: moving STA 74:83:c2:64:0b:87 to state 3 . . wlan0: expiring inactive not authorized STA 74:83:c2:64:0b:87 wlan0: moving STA 74:83:c2:64:0b:87 to state 2 wlan0: moving STA 74:83:c2:64:0b:87 to state 1 wlan0: Removed STA 74:83:c2:64:0b:87 wlan0: Destroyed STA 74:83:c2:64:0b:87 The ieee80211_ibss_finish_sta() is called twice on the same STA from 2 different locations. On the second attempt, the allocated STA is not destroyed creating a kernel memory leak. This is happening because sta_info_insert_finish() does not call sta_info_free() the second time when the STA already exists (returns -EEXIST). Note that the caller sta_info_insert_rcu() assumes STA is destroyed upon errors. Same fix is applied to -ENOMEM. Signed-off-by: Ahmed Zaki <anzaki@gmail.com> --- net/mac80211/sta_info.c | 2 ++ 1 file changed, 2 insertions(+)