kernel/git/stable/linux.git/net/mac80211/key.c, branch linux-4.9.y

mac80211: drop data frames without key on encrypted links

2021-08-26T12:37:25+00:00

commit a0761a301746ec2d92d7fcb82af69c0a6a4339aa upstream. If we know that we have an encrypted link (based on having had a key configured for TX in the past) then drop all data frames in the key selection handler if there's no key anymore. This fixes an issue with mac80211 internal TXQs - there we can buffer frames for an encrypted link, but then if the key is no longer there when they're dequeued, the frames are sent without encryption. This happens if a station is disconnected while the frames are still on the TXQ. Detecting that a link should be encrypted based on a first key having been configured for TX is fine as there are no use cases for a connection going from with encryption to no encryption. With extended key IDs, however, there is a case of having a key configured for only decryption, so we can't just trigger this behaviour on a key being configured. Cc: stable@vger.kernel.org Reported-by: Jouni Malinen Signed-off-by: Johannes Berg Signed-off-by: Luca Coelho Link: https://lore.kernel.org/r/iwlwifi.20200326150855.6865c7f28a14.I9fb1d911b064262d33e33dfba730cdeef83926ca@changeid Signed-off-by: Johannes Berg [pali: Backported to 4.19 and older versions] Signed-off-by: Pali Rohár Signed-off-by: Greg Kroah-Hartman

mac80211: prevent mixed key and fragment cache attacks

2021-06-03T06:23:28+00:00

commit 94034c40ab4a3fcf581fbc7f8fdf4e29943c4a24 upstream. Simultaneously prevent mixed key attacks (CVE-2020-24587) and fragment cache attacks (CVE-2020-24586). This is accomplished by assigning a unique color to every key (per interface) and using this to track which key was used to decrypt a fragment. When reassembling frames, it is now checked whether all fragments were decrypted using the same key. To assure that fragment cache attacks are also prevented, the ID that is assigned to keys is unique even over (re)associations and (re)connects. This means fragments separated by a (re)association or (re)connect will not be reassembled. Because mac80211 now also prevents the reassembly of mixed encrypted and plaintext fragments, all cache attacks are prevented. Cc: stable@vger.kernel.org Signed-off-by: Mathy Vanhoef Link: https://lore.kernel.org/r/20210511200110.3f8290e59823.I622a67769ed39257327a362cfc09c812320eb979@changeid Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman

mac80211: restrict delayed tailroom needed decrement

2018-09-26T06:36:33+00:00

[ 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

2017-11-18T10:22:24+00:00

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

2017-11-18T10:22:23+00:00

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

2017-11-18T10:22:23+00:00

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

mac80211: add fast-rx path

2016-04-06T11:18:18+00:00

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

2016-02-24T08:04:39+00:00

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

2016-02-24T08:04:38+00:00

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

mac80211: add atomic uploaded keys iterator

2015-12-04T13:43:32+00:00

add ieee80211_iter_keys_rcu() to iterate over uploaded keys in atomic context (when rcu is locked) The station removal code removes the keys only after calling synchronize_net(), so it's not safe to iterate the keys at this point (and postponing the actual key deletion with call_rcu() might result in some badly-ordered ops calls). Add a flag to indicate a station is being removed, and skip the configured keys if it's set. Signed-off-by: Eliad Peller Signed-off-by: Emmanuel Grumbach Signed-off-by: Johannes Berg