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| author |   Michal Kazior <michal.kazior@tieto.com> | 2015-05-22 10:57:22 +0200 |
|---|---|---|
| committer |   Johannes Berg <johannes.berg@intel.com> | 2015-05-29 13:05:40 +0200 |
| commit | 6cbfb1bb66e4e85da5db78e8ff429a85bd84ce64 (patch) | |
| tree | a308cacf6f712c7842b7df95c66877fbac3220b0 /net/wireless | |
| parent | mac80211: prevent possible crypto tx tailroom corruption (diff) | |
| download | linux-dev-6cbfb1bb66e4e85da5db78e8ff429a85bd84ce64.tar.xz linux-dev-6cbfb1bb66e4e85da5db78e8ff429a85bd84ce64.zip | |
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')
| -rw-r--r-- | net/wireless/util.c | 2 |
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; wdev_lock(dev->ieee80211_ptr); |