kernel.git/net/mac80211/key.c, branch linux-3.18.y

mac80211: restrict delayed tailroom needed decrement

2018-09-26T06:33:56Z

[ Upstream commit 133bf90dbb8b873286f8ec2e81ba26e863114b8c ] As explained in ieee80211_delayed_tailroom_dec(), during roam, keys of the old AP will be destroyed and new keys will be installed. Deletion of the old key causes crypto_tx_tailroom_needed_cnt to go from 1 to 0 and the new key installation causes a transition from 0 to 1. Whenever crypto_tx_tailroom_needed_cnt transitions from 0 to 1, we invoke synchronize_net(); the reason for doing this is to avoid a race in the TX path as explained in increment_tailroom_need_count(). This synchronize_net() operation can be slow and can affect the station roam time. To avoid this, decrementing the crypto_tx_tailroom_needed_cnt is delayed for a while so that upon installation of new key the transition would be from 1 to 2 instead of 0 to 1 and thereby improving the roam time. This is all correct for a STA iftype, but deferring the tailroom_needed decrement for other iftypes may be unnecessary. For example, let's consider the case of a 4-addr client connecting to an AP for which AP_VLAN interface is also created, let the initial value for tailroom_needed on the AP be 1. * 4-addr client connects to the AP (AP: tailroom_needed = 1) * AP will clear old keys, delay decrement of tailroom_needed count * AP_VLAN is created, it takes the tailroom count from master (AP_VLAN: tailroom_needed = 1, AP: tailroom_needed = 1) * Install new key for the station, assume key is plumbed in the HW, there won't be any change in tailroom_needed count on AP iface * Delayed decrement of tailroom_needed count on AP (AP: tailroom_needed = 0, AP_VLAN: tailroom_needed = 1) Because of the delayed decrement on AP iface, tailroom_needed count goes out of sync between AP(master iface) and AP_VLAN(slave iface) and there would be unnecessary tailroom created for the packets going through AP_VLAN iface. Also, WARN_ONs were observed while trying to bring down the AP_VLAN interface: (warn_slowpath_common) (warn_slowpath_null+0x18/0x20) (warn_slowpath_null) (ieee80211_free_keys+0x114/0x1e4) (ieee80211_free_keys) (ieee80211_del_virtual_monitor+0x51c/0x850) (ieee80211_del_virtual_monitor) (ieee80211_stop+0x30/0x3c) (ieee80211_stop) (__dev_close_many+0x94/0xb8) (__dev_close_many) (dev_close_many+0x5c/0xc8) Restricting delayed decrement to station interface alone fixes the problem and it makes sense to do so because delayed decrement is done to improve roam time which is applicable only for client devices. Signed-off-by: Manikanta Pubbisetty Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

mac80211: don't compare TKIP TX MIC key in reinstall prevention

2017-11-18T10:06:29Z

commit cfbb0d90a7abb289edc91833d0905931f8805f12 upstream. For the reinstall prevention, the code I had added compares the whole key. It turns out though that iwlwifi firmware doesn't provide the TKIP TX MIC key as it's not needed in client mode, and thus the comparison will always return false. For client mode, thus always zero out the TX MIC key part before doing the comparison in order to avoid accepting the reinstall of the key with identical encryption and RX MIC key, but not the same TX MIC key (since the supplicant provides the real one.) Fixes: fdf7cb4185b6 ("mac80211: accept key reinstall without changing anything") Signed-off-by: Johannes Berg Cc: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

mac80211: use constant time comparison with keys

2017-11-18T10:06:29Z

commit 2bdd713b92a9cade239d3c7d15205a09f556624d upstream. Otherwise we risk leaking information via timing side channel. Fixes: fdf7cb4185b6 ("mac80211: accept key reinstall without changing anything") Signed-off-by: Jason A. Donenfeld Signed-off-by: Johannes Berg Cc: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

mac80211: accept key reinstall without changing anything

2017-11-18T10:06:29Z

commit fdf7cb4185b60c68e1a75e61691c4afdc15dea0e upstream. When a key is reinstalled we can reset the replay counters etc. which can lead to nonce reuse and/or replay detection being impossible, breaking security properties, as described in the "KRACK attacks". In particular, CVE-2017-13080 applies to GTK rekeying that happened in firmware while the host is in D3, with the second part of the attack being done after the host wakes up. In this case, the wpa_supplicant mitigation isn't sufficient since wpa_supplicant doesn't know the GTK material. In case this happens, simply silently accept the new key coming from userspace but don't take any action on it since it's the same key; this keeps the PN replay counters intact. Signed-off-by: Johannes Berg Cc: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

Revert "mac80211: Fix accounting of the tailroom-needed counter"

2015-01-16T14:59:56Z

commit 1e359a5de861a57aa04d92bb620f52a5c1d7f8b1 upstream. This reverts commit ca34e3b5c808385b175650605faa29e71e91991b. It turns out that the p54 and cw2100 drivers assume that there's tailroom even when they don't say they really need it. However, there's currently no way for them to explicitly say they do need it, so for now revert this. This fixes https://bugzilla.kernel.org/show_bug.cgi?id=90331. Fixes: ca34e3b5c808 ("mac80211: Fix accounting of the tailroom-needed counter") Reported-by: Christopher Chavez Bisected-by: Larry Finger Debugged-by: Christian Lamparter Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman

mac80211: free management frame keys when removing station

2015-01-08T18:30:23Z

commit 28a9bc68124c319b2b3dc861e80828a8865fd1ba upstream. When writing the code to allow per-station GTKs, I neglected to take into account the management frame keys (index 4 and 5) when freeing the station and only added code to free the first four data frame keys. Fix this by iterating the array of keys over the right length. Fixes: e31b82136d1a ("cfg80211/mac80211: allow per-station GTKs") Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman

mac80211: clear key material when freeing keys

2014-09-11T10:07:23Z

When freeing the key, clear the memory to avoid having the key material stick around in memory "forever". Signed-off-by: Johannes Berg

mac80211: add Intel Mobile Communications copyright

2014-09-05T11:52:06Z

Our legal structure changed at some point (see wikipedia), but we forgot to immediately switch over to the new copyright notice. For files that we have modified in the time since the change, add the proper copyright notice now. Signed-off-by: Johannes Berg Signed-off-by: Emmanuel Grumbach Signed-off-by: Johannes Berg

mac80211: Fix accounting of the tailroom-needed counter

2014-08-26T09:15:59Z

When hw acceleration is enabled, the GENERATE_IV or PUT_IV_SPACE flags will only require headroom space. Consequently, the tailroom-needed counter can safely be decremented. Signed-off-by: Ido Yariv Signed-off-by: Emmanuel Grumbach Signed-off-by: Johannes Berg

mac80211: remove useless NULL checks

2014-07-21T14:04:27Z

sdata can't be NULL, and key being NULL is really not possible unless the code is modified. The sdata check made a static analyze (klocwork) unhappy because we would get pointer to local (sdata->local) and only then check if sdata is non-NULL. Signed-off-by: Eytan Lifshitz Signed-off-by: Emmanuel Grumbach [remove !key check as well] Signed-off-by: Johannes Berg