path: root/net/wireless/util.c
diff options
authorMichal Kazior <michal.kazior@tieto.com>2015-05-22 10:57:22 +0200
committerJohannes Berg <johannes.berg@intel.com>2015-05-29 13:05:40 +0200
commit6cbfb1bb66e4e85da5db78e8ff429a85bd84ce64 (patch)
treea308cacf6f712c7842b7df95c66877fbac3220b0 /net/wireless/util.c
parentab499db80fcf07c18e4053f91a619500f663e90e (diff)
cfg80211: ignore netif running state when changing iftype
It was possible for mac80211 to be coerced into an unexpected flow causing sdata union to become corrupted. Station pointer was put into sdata->u.vlan.sta memory location while it was really master AP's sdata->u.ap.next_beacon. This led to station entry being later freed as next_beacon before __sta_info_flush() in ieee80211_stop_ap() and a subsequent invalid pointer dereference crash. The problem was that ieee80211_ptr->use_4addr wasn't cleared on interface type changes. This could be reproduced with the following steps: # host A and host B have just booted; no # wpa_s/hostapd running; all vifs are down host A> iw wlan0 set type station host A> iw wlan0 set 4addr on host A> printf 'interface=wlan0\nssid=4addrcrash\nchannel=1\nwds_sta=1' > /tmp/hconf host A> hostapd -B /tmp/conf host B> iw wlan0 set 4addr on host B> ifconfig wlan0 up host B> iw wlan0 connect -w hostAssid host A> pkill hostapd # host A crashed: [ 127.928192] BUG: unable to handle kernel NULL pointer dereference at 00000000000006c8 [ 127.929014] IP: [<ffffffff816f4f32>] __sta_info_flush+0xac/0x158 ... [ 127.934578] [<ffffffff8170789e>] ieee80211_stop_ap+0x139/0x26c [ 127.934578] [<ffffffff8100498f>] ? dump_trace+0x279/0x28a [ 127.934578] [<ffffffff816dc661>] __cfg80211_stop_ap+0x84/0x191 [ 127.934578] [<ffffffff816dc7ad>] cfg80211_stop_ap+0x3f/0x58 [ 127.934578] [<ffffffff816c5ad6>] nl80211_stop_ap+0x1b/0x1d [ 127.934578] [<ffffffff815e53f8>] genl_family_rcv_msg+0x259/0x2b5 Note: This isn't a revert of f8cdddb8d61d ("cfg80211: check iface combinations only when iface is running") as far as functionality is considered because b6a550156bc ("cfg80211/mac80211: move more combination checks to mac80211") moved the logic somewhere else already. Fixes: f8cdddb8d61d ("cfg80211: check iface combinations only when iface is running") Signed-off-by: Michal Kazior <michal.kazior@tieto.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/wireless/util.c')
1 files changed, 1 insertions, 1 deletions
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 4cb34557b873..baf7218cec15 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -945,7 +945,7 @@ int cfg80211_change_iface(struct cfg80211_registered_device *rdev,
ntype == NL80211_IFTYPE_P2P_CLIENT))
return -EBUSY;
- if (ntype != otype && netif_running(dev)) {
+ if (ntype != otype) {
dev->ieee80211_ptr->use_4addr = false;
dev->ieee80211_ptr->mesh_id_up_len = 0;