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cfg80211: fix a bunch of RCU issues in multi-bssid code

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cfg80211_update_notlisted_nontrans() leaves the RCU critical session
too early, while still using nontrans_ssid which is RCU protected. In
addition, it performs a bunch of RCU pointer update operations such
as rcu_access_pointer and rcu_assign_pointer.

The caller, cfg80211_inform_bss_frame_data(), also accesses the RCU
pointer without holding the lock.

Just wrap all of this with bss_lock.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/20191004123706.15768-3-luca@coelho.fi
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Sara Sharon 2019-10-04 15:37:06 +03:00 committed by Johannes Berg
parent 1399c59fa9
commit 461c4c2b4c
1 changed files with 13 additions and 10 deletions
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23
net/wireless/scan.c
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@ -1703,8 +1703,7 @@ cfg80211_parse_mbssid_frame_data(struct wiphy *wiphy,
static void
cfg80211_update_notlisted_nontrans(struct wiphy *wiphy,
struct cfg80211_bss *nontrans_bss,
struct ieee80211_mgmt *mgmt, size_t len,
gfp_t gfp)
struct ieee80211_mgmt *mgmt, size_t len)
{
u8 *ie, *new_ie, *pos;
const u8 *nontrans_ssid, *trans_ssid, *mbssid;
@ -1715,6 +1714,8 @@ cfg80211_update_notlisted_nontrans(struct wiphy *wiphy,
const struct cfg80211_bss_ies *old;
u8 cpy_len;
lockdep_assert_held(&wiphy_to_rdev(wiphy)->bss_lock);
ie = mgmt->u.probe_resp.variable;
new_ie_len = ielen;
@ -1731,23 +1732,22 @@ cfg80211_update_notlisted_nontrans(struct wiphy *wiphy,
if (!mbssid || mbssid < trans_ssid)
return;
new_ie_len -= mbssid[1];
rcu_read_lock();
nontrans_ssid = ieee80211_bss_get_ie(nontrans_bss, WLAN_EID_SSID);
if (!nontrans_ssid) {
rcu_read_unlock();
if (!nontrans_ssid)
return;
}
new_ie_len += nontrans_ssid[1];
rcu_read_unlock();
/* generate new ie for nontrans BSS
* 1. replace SSID with nontrans BSS' SSID
* 2. skip MBSSID IE
*/
new_ie = kzalloc(new_ie_len, gfp);
new_ie = kzalloc(new_ie_len, GFP_ATOMIC);
if (!new_ie)
return;
new_ies = kzalloc(sizeof(*new_ies) + new_ie_len, gfp);
new_ies = kzalloc(sizeof(*new_ies) + new_ie_len, GFP_ATOMIC);
if (!new_ies)
goto out_free;
@ -1901,6 +1901,8 @@ cfg80211_inform_bss_frame_data(struct wiphy *wiphy,
cfg80211_parse_mbssid_frame_data(wiphy, data, mgmt, len,
&non_tx_data, gfp);
spin_lock_bh(&wiphy_to_rdev(wiphy)->bss_lock);
/* check if the res has other nontransmitting bss which is not
* in MBSSID IE
*/
@ -1915,8 +1917,9 @@ cfg80211_inform_bss_frame_data(struct wiphy *wiphy,
ies2 = rcu_access_pointer(tmp_bss->ies);
if (ies2->tsf < ies1->tsf)
cfg80211_update_notlisted_nontrans(wiphy, tmp_bss,
mgmt, len, gfp);
mgmt, len);
}
spin_unlock_bh(&wiphy_to_rdev(wiphy)->bss_lock);
return res;
}