From 431cb63afee9109afcd8bcd780e8f6031d4356cf Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Thu, 30 Sep 2021 13:11:21 +0200 Subject: [PATCH] cfg80211: scan: fix RCU in cfg80211_add_nontrans_list() commit a2083eeb119fb9307258baea9b7c243ca9a2e0b6 upstream. The SSID pointer is pointing to RCU protected data, so we need to have it under rcu_read_lock() for the entire use. Fix this. Cc: stable@vger.kernel.org Fixes: ac2a324087a0 ("cfg80211: Parsing of Multiple BSSID information in scanning") Link: https://lore.kernel.org/r/20210930131120.6ddfc603aa1d.I2137344c4e2426525b1a8e4ce5fca82f8ecbfe7e@changeid Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/wireless/scan.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/net/wireless/scan.c b/net/wireless/scan.c index 1580535d53f86..6cefaad3b7f84 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -379,14 +379,17 @@ cfg80211_add_nontrans_list(struct cfg80211_bss *trans_bss, } ssid_len = ssid[1]; ssid = ssid + 2; - rcu_read_unlock(); /* check if nontrans_bss is in the list */ list_for_each_entry(bss, &trans_bss->nontrans_list, nontrans_list) { - if (is_bss(bss, nontrans_bss->bssid, ssid, ssid_len)) + if (is_bss(bss, nontrans_bss->bssid, ssid, ssid_len)) { + rcu_read_unlock(); return 0; + } } + rcu_read_unlock(); + /* add to the list */ list_add_tail(&nontrans_bss->nontrans_list, &trans_bss->nontrans_list); return 0; -- 2.39.5