netdev - [PATCH] nl80211: take RCU read lock when calling ieee80211_bss_get

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20180114180338.GA1569@light.dominikbrodowski.net>
Date:   Sun, 14 Jan 2018 19:03:38 +0100
From:   Dominik Brodowski <linux@...inikbrodowski.net>
To:     johannes.berg@...el.com
Cc:     regressions@...mhuis.info, netdev@...r.kernel.org,
        linux-wireless@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] nl80211: take RCU read lock when calling
 ieee80211_bss_get_ie()

As ieee80211_bss_get_ie() derefences an RCU, it needs to be called with
rcu_read_lock held.

Fixes: 44905265bc15 ("nl80211: don't expose wdev->ssid for most interfaces")
Signed-off-by: Dominik Brodowski <linux@...inikbrodowski.net>
---

This patch fixes the regression I reported in the last couple of weeks for
various v4.15-rcX revisions to netdev, where a "suspicious RCU usage"
showed up in net/wireless/util.c:778.

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 2b3dbcd40e46..1eecc249fb5e 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -2618,8 +2618,10 @@ static int nl80211_send_iface(struct sk_buff *msg, u32 portid, u32 seq, int flag
 		const u8 *ssid_ie;
 		if (!wdev->current_bss)
 			break;
+		rcu_read_lock();
 		ssid_ie = ieee80211_bss_get_ie(&wdev->current_bss->pub,
 					       WLAN_EID_SSID);
+		rcu_read_unlock();
 		if (!ssid_ie)
 			break;
 		if (nla_put(msg, NL80211_ATTR_SSID, ssid_ie[1], ssid_ie + 2))