[PATCH AUTOSEL 5.12 07/39] cfg80211: call cfg80211_leave_ocb when switching away from OCB

Sasha Levin
2021-06-21T17:52:25Z

From: Du Cheng <ducheng2@gmail.com>

[ Upstream commit a64b6a25dd9f984ed05fade603a00e2eae787d2f ]

If the userland switches back-and-forth between NL80211_IFTYPE_OCB and
NL80211_IFTYPE_ADHOC via send_msg(NL80211_CMD_SET_INTERFACE), there is a
chance where the cleanup cfg80211_leave_ocb() is not called. This leads
to initialization of in-use memory (e.g. init u.ibss while in-use by
u.ocb) due to a shared struct/union within ieee80211_sub_if_data:

struct ieee80211_sub_if_data {
...
union {
struct ieee80211_if_ap ap;
struct ieee80211_if_vlan vlan;
struct ieee80211_if_managed mgd;
struct ieee80211_if_ibss ibss; // <- shares address
struct ieee80211_if_mesh mesh;
struct ieee80211_if_ocb ocb; // <- shares address
struct ieee80211_if_mntr mntr;
struct ieee80211_if_nan nan;
} u;
...
}

Therefore add handling of otype == NL80211_IFTYPE_OCB, during
cfg80211_change_iface() to perform cleanup when leaving OCB mode.

link to syzkaller bug:
https://syzkaller.appspot.com/bug?id=0612dbfa595bf4b9b680ff7b4948257b8e3732d5

Reported-by: syzbot+105896fac213f26056f9@syzkaller.appspotmail.com
Signed-off-by: Du Cheng <ducheng2@gmail.com>
Link: https://lore.kernel.org/r/20210428063941.105161-1-ducheng2@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/wireless/util.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/net/wireless/util.c b/net/wireless/util.c
index f342b6147675..726e7d2342bd 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -1059,6 +1059,9 @@ int cfg80211_change_iface(struct cfg80211_registered_device *rdev,
case NL80211_IFTYPE_MESH_POINT:
/* mesh should be handled? */
break;
+ case NL80211_IFTYPE_OCB:
+ cfg80211_leave_ocb(rdev, dev);
+ break;
default:
break;
}
--
2.30.2