The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 51e13359cd5ea34acc62c90627603352956380af Mon Sep 17 00:00:00 2001 From: Johannes Berg <johannes.berg@xxxxxxxxx> Date: Tue, 17 Oct 2017 21:56:20 +0200 Subject: [PATCH] cfg80211: fix connect/disconnect edge cases If we try to connect while already connected/connecting, but this fails, we set ssid_len=0 but leave current_bss hanging, leading to errors. Check all of this better, first of all ensuring that we can't try to connect to a different SSID while connected/ing; ensure that prev_bssid is set for re-association attempts even in the case of the driver supporting the connect() method, and don't reset ssid_len in the failure cases. While at it, also reset ssid_len while disconnecting unless we were connected and expect a disconnected event, and warn on a successful connection without ssid_len being set. Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> diff --git a/net/wireless/sme.c b/net/wireless/sme.c index 0a49b88070d0..b6533ecbf5b1 100644 --- a/net/wireless/sme.c +++ b/net/wireless/sme.c @@ -522,11 +522,6 @@ static int cfg80211_sme_connect(struct wireless_dev *wdev, return -EOPNOTSUPP; if (wdev->current_bss) { - if (!prev_bssid) - return -EALREADY; - if (prev_bssid && - !ether_addr_equal(prev_bssid, wdev->current_bss->pub.bssid)) - return -ENOTCONN; cfg80211_unhold_bss(wdev->current_bss); cfg80211_put_bss(wdev->wiphy, &wdev->current_bss->pub); wdev->current_bss = NULL; @@ -1063,11 +1058,35 @@ int cfg80211_connect(struct cfg80211_registered_device *rdev, ASSERT_WDEV_LOCK(wdev); - if (WARN_ON(wdev->connect_keys)) { - kzfree(wdev->connect_keys); - wdev->connect_keys = NULL; + /* + * If we have an ssid_len, we're trying to connect or are + * already connected, so reject a new SSID unless it's the + * same (which is the case for re-association.) + */ + if (wdev->ssid_len && + (wdev->ssid_len != connect->ssid_len || + memcmp(wdev->ssid, connect->ssid, wdev->ssid_len))) + return -EALREADY; + + /* + * If connected, reject (re-)association unless prev_bssid + * matches the current BSSID. + */ + if (wdev->current_bss) { + if (!prev_bssid) + return -EALREADY; + if (!ether_addr_equal(prev_bssid, wdev->current_bss->pub.bssid)) + return -ENOTCONN; } + /* + * Reject if we're in the process of connecting with WEP, + * this case isn't very interesting and trying to handle + * it would make the code much more complex. + */ + if (wdev->connect_keys) + return -EINPROGRESS; + cfg80211_oper_and_ht_capa(&connect->ht_capa_mask, rdev->wiphy.ht_capa_mod_mask); @@ -1118,7 +1137,12 @@ int cfg80211_connect(struct cfg80211_registered_device *rdev, if (err) { wdev->connect_keys = NULL; - wdev->ssid_len = 0; + /* + * This could be reassoc getting refused, don't clear + * ssid_len in that case. + */ + if (!wdev->current_bss) + wdev->ssid_len = 0; return err; } @@ -1145,6 +1169,14 @@ int cfg80211_disconnect(struct cfg80211_registered_device *rdev, else if (wdev->ssid_len) err = rdev_disconnect(rdev, dev, reason); + /* + * Clear ssid_len unless we actually were fully connected, + * in which case cfg80211_disconnected() will take care of + * this later. + */ + if (!wdev->current_bss) + wdev->ssid_len = 0; + return err; }