2021-06-21 17:56:12

by Sasha Levin

[permalink] [raw]
Subject: [PATCH AUTOSEL 5.10 07/35] cfg80211: call cfg80211_leave_ocb when switching away from OCB

From: Du Cheng <[email protected]>

[ 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:

Reported-by: [email protected]
Signed-off-by: Du Cheng <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Johannes Berg <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
net/wireless/util.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/net/wireless/util.c b/net/wireless/util.c
index 2731267fd0f9..4fb8d1b14e76 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -1059,6 +1059,9 @@ int cfg80211_change_iface(struct cfg80211_registered_device *rdev,
/* mesh should be handled? */
+ case NL80211_IFTYPE_OCB:
+ cfg80211_leave_ocb(rdev, dev);
+ break;