kernel.git/net/mac80211/key.c, branch linux-4.18.y

mac80211: restrict delayed tailroom needed decrement

2018-09-26T06:39:26Z

[ 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: allow AP_VLAN operation on crypto controlled devices

2018-03-29T09:35:22Z

In the current implementation, mac80211 advertises the support of AP_VLANs based on the driver's support for AP mode; it also blocks encrypted AP_VLAN operation on devices advertising SW_CRYPTO_CONTROL. The implementation seems weird in it's current form and could be often confusing, this is because there can be drivers advertising both SW_CRYPTO_CONTROL and AP mode support (ex: ath10k) in which case AP_VLAN will still be supported but only in open BSS and not in secured BSS. When SW_CRYPTO_CONTROL is enabled, it makes more sense if the decision to support AP_VLANs is left to the driver. Mac80211 can then allow AP_VLAN operations depending on the driver support. Signed-off-by: Manikanta Pubbisetty Signed-off-by: Johannes Berg

mac80211: Add MIC space only for TX key option

2017-12-11T11:20:17Z

Add a key flag to indicates that the device only needs MIC space and not a real MIC. In such cases, keep the MIC zeroed for ease of debug. Signed-off-by: David Spinadel Signed-off-by: Luca Coelho Signed-off-by: Johannes Berg

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

2017-10-25T09:04:45Z

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

mac80211: use constant time comparison with keys

2017-10-18T07:39:14Z

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

mac80211: accept key reinstall without changing anything

2017-10-16T11:02:03Z

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

mac80211: don't call drv_set_default_unicast_key() for VLANs

2016-12-13T14:57:59Z

Since drivers know nothing about AP_VLAN interfaces, trying to call drv_set_default_unicast_key() just results in a warning and no call to the driver. Avoid the warning by not calling the driver for this on AP_VLAN interfaces. This means that drivers that somehow need this call for AP mode will fail to work properly in the presence of VLAN interfaces, but the current drivers don't seem to use it, and mac80211 will select and indicate the key - so drivers should be OK now. Reported-by: Jouni Malinen Signed-off-by: Johannes Berg

mac80211: add fast-rx path

2016-04-06T11:18:18Z

The regular RX path has a lot of code, but with a few assumptions on the hardware it's possible to reduce the amount of code significantly. Currently the assumptions on the driver are the following: * hardware/driver reordering buffer (if supporting aggregation) * hardware/driver decryption & PN checking (if using encryption) * hardware/driver did de-duplication * hardware/driver did A-MSDU deaggregation * AP_LINK_PS is used (in AP mode) * no client powersave handling in mac80211 (in client mode) of which some are actually checked per packet: * de-duplication * PN checking * decryption and additionally packets must * not be A-MSDU (have been deaggregated by driver/device) * be data packets * not be fragmented * be unicast * have RFC 1042 header Additionally dynamically we assume: * no encryption or CCMP/GCMP, TKIP/WEP/other not allowed * station must be authorized * 4-addr format not enabled Some data needed for the RX path is cached in a new per-station "fast_rx" structure, so that we only need to look at this and the packet, no other memory when processing packets on the fast RX path. After doing the above per-packet checks, the data path collapses down to a pretty simple conversion function taking advantage of the data cached in the small fast_rx struct. This should speed up the RX processing, and will make it easier to reason about parallelizing RX (for which statistics will need to be per-CPU still.) Signed-off-by: Johannes Berg

mac80211: remove ieee80211_get_key_tx_seq/ieee80211_set_key_tx_seq

2016-02-24T08:04:39Z

Since the PNs of all the tx keys are now tracked in the public part of the key struct (with atomic counter), we no longer need these functions. dvm and vt665{5,6} are currently the only users of these functions, so update them accordingly. Signed-off-by: Eliad Peller Signed-off-by: Emmanuel Grumbach Signed-off-by: Johannes Berg

mac80211: move TKIP TX IVs to public part of key struct

2016-02-24T08:04:38Z

Some drivers/devices might want to set the IVs by themselves (and still let mac80211 generate MMIC). Specifically, this is needed when the device does offloading at certain times, and the driver has to make sure that the IVs of new tx frames (from the host) are synchronized with IVs that were potentially used during the offloading. Similarly to CCMP, move the TX IVs of TKIP keys to the public part of the key struct, and export a function to add the IV right into the crypto header. The public tx_pn field is defined as atomic64, so define TKIP_PN_TO_IV16/32 helper macros to convert it to iv16/32 when needed. Since the iv32 used for the p1k cache is taken directly from the frame, we can safely remove iv16/32 from being protected by tkip.txlock. Signed-off-by: Eliad Peller Signed-off-by: Emmanuel Grumbach Signed-off-by: Johannes Berg