kernel/linux.git/net/mac80211/key.c, branch linux-4.4.y

mac80211: prevent mixed key and fragment cache attacks

2021-06-03T06:22:05+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

2018-09-26T06:35:06+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

2017-11-18T10:11:05+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

2017-11-18T10:11:05+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

2017-11-18T10:11:04+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: remove sta_info.gtk_idx

2015-07-17T13:37:54+00:00

This struct member is only assigned, never used otherwise; remove it. Signed-off-by: Johannes Berg

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2015-06-24T09:58:51+00:00

Conflicts: drivers/net/ethernet/mellanox/mlx4/main.c net/packet/af_packet.c Both conflicts were cases of simple overlapping changes. Signed-off-by: David S. Miller

mac80211: fix locking in update_vlan_tailroom_need_count()

2015-06-21T17:06:07+00:00

Unfortunately, Michal's change to fix AP_VLAN crypto tailroom caused a locking issue that was reported by lockdep, but only in a few cases - the issue was a classic ABBA deadlock caused by taking the mtx after the key_mtx, where normally they're taken the other way around. As the key mutex protects the field in question (I'm adding a few annotations to make that clear) only the iteration needs to be protected, but we can also iterate the interface list with just RCU protection while holding the key mutex. Fixes: f9dca80b98ca ("mac80211: fix AP_VLAN crypto tailroom calculation") Signed-off-by: Johannes Berg Signed-off-by: David S. Miller

mac80211: convert HW flags to unsigned long bitmap

2015-06-10T14:05:36+00:00

As we're running out of hardware capability flags pretty quickly, convert them to use the regular test_bit() style unsigned long bitmaps. This introduces a number of helper functions/macros to set and to test the bits, along with new debugfs code. The occurrences of an explicit __clear_bit() are intentional, the drivers were never supposed to change their supported bits on the fly. We should investigate changing this to be a per-frame flag. Signed-off-by: Johannes Berg

Merge remote-tracking branch 'net-next/master' into mac80211-next

2015-06-10T10:45:09+00:00

Merge back net-next to get wireless driver changes (from Kalle) to be able to create the API change across all trees properly. Signed-off-by: Johannes Berg