linux-stable.git/net/mac80211, branch v4.4.271

mac80211: extend protection against mixed key and fragment cache attacks

2021-06-03T06:22:05+00:00

commit 3edc6b0d6c061a70d8ca3c3c72eb1f58ce29bfb1 upstream.

For some chips/drivers, e.g., QCA6174 with ath10k, the decryption is
done by the hardware, and the Protected bit in the Frame Control field
is cleared in the lower level driver before the frame is passed to
mac80211. In such cases, the condition for ieee80211_has_protected() is
not met in ieee80211_rx_h_defragment() of mac80211 and the new security
validation steps are not executed.

Extend mac80211 to cover the case where the Protected bit has been
cleared, but the frame is indicated as having been decrypted by the
hardware. This extends protection against mixed key and fragment cache
attack for additional drivers/chips. This fixes CVE-2020-24586 and
CVE-2020-24587 for such cases.

Tested-on: QCA6174 hw3.2 PCI WLAN.RM.4.4.1-00110-QCARMSWP-1

Cc: stable@vger.kernel.org
Signed-off-by: Wen Gong 
Signed-off-by: Jouni Malinen 
Link: https://lore.kernel.org/r/20210511200110.037aa5ca0390.I7bb888e2965a0db02a67075fcb5deb50eb7408aa@changeid
Signed-off-by: Johannes Berg 
Signed-off-by: Greg Kroah-Hartman

mac80211: do not accept/forward invalid EAPOL frames

2021-06-03T06:22:05+00:00

commit a8c4d76a8dd4fb9666fc8919a703d85fb8f44ed8 upstream.

EAPOL frames are used for authentication and key management between the
AP and each individual STA associated in the BSS. Those frames are not
supposed to be sent by one associated STA to another associated STA
(either unicast for broadcast/multicast).

Similarly, in 802.11 they're supposed to be sent to the authenticator
(AP) address.

Since it is possible for unexpected EAPOL frames to result in misbehavior
in supplicant implementations, it is better for the AP to not allow such
cases to be forwarded to other clients either directly, or indirectly if
the AP interface is part of a bridge.

Accept EAPOL (control port) frames only if they're transmitted to the
own address, or, due to interoperability concerns, to the PAE group
address.

Disable forwarding of EAPOL (or well, the configured control port
protocol) frames back to wireless medium in all cases. Previously, these
frames were accepted from fully authenticated and authorized stations
and also from unauthenticated stations for one of the cases.

Additionally, to avoid forwarding by the bridge, rewrite the PAE group
address case to the local MAC address.

Cc: stable@vger.kernel.org
Co-developed-by: Jouni Malinen 
Signed-off-by: Jouni Malinen 
Link: https://lore.kernel.org/r/20210511200110.cb327ed0cabe.Ib7dcffa2a31f0913d660de65ba3c8aca75b1d10f@changeid
Signed-off-by: Johannes Berg 
Signed-off-by: Greg Kroah-Hartman

mac80211: prevent attacks on TKIP/WEP as well

2021-06-03T06:22:05+00:00

commit 7e44a0b597f04e67eee8cdcbe7ee706c6f5de38b upstream.

Similar to the issues fixed in previous patches, TKIP and WEP
should be protected even if for TKIP we have the Michael MIC
protecting it, and WEP is broken anyway.

However, this also somewhat protects potential other algorithms
that drivers might implement.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210511200110.430e8c202313.Ia37e4e5b6b3eaab1a5ae050e015f6c92859dbe27@changeid
Signed-off-by: Johannes Berg 
Signed-off-by: Greg Kroah-Hartman

mac80211: check defrag PN against current frame

2021-06-03T06:22:05+00:00

commit bf30ca922a0c0176007e074b0acc77ed345e9990 upstream.

As pointed out by Mathy Vanhoef, we implement the RX PN check
on fragmented frames incorrectly - we check against the last
received PN prior to the new frame, rather than to the one in
this frame itself.

Prior patches addressed the security issue here, but in order
to be able to reason better about the code, fix it to really
compare against the current frame's PN, not the last stored
one.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210511200110.bfbc340ff071.Id0b690e581da7d03d76df90bb0e3fd55930bc8a0@changeid
Signed-off-by: Johannes Berg 
Signed-off-by: Greg Kroah-Hartman

mac80211: add fragment cache to sta_info

2021-06-03T06:22:05+00:00

commit 3a11ce08c45b50d69c891d71760b7c5b92074709 upstream.

Prior patches protected against fragmentation cache attacks
by coloring keys, but this shows that it can lead to issues
when multiple stations use the same sequence number. Add a
fragment cache to struct sta_info (in addition to the one in
the interface) to separate fragments for different stations
properly.

This then automatically clear most of the fragment cache when a
station disconnects (or reassociates) from an AP, or when client
interfaces disconnect from the network, etc.

On the way, also fix the comment there since this brings us in line
with the recommendation in 802.11-2016 ("An AP should support ...").
Additionally, remove a useless condition (since there's no problem
purging an already empty list).

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210511200110.fc35046b0d52.I1ef101e3784d13e8f6600d83de7ec9a3a45bcd52@changeid
Signed-off-by: Johannes Berg 
Signed-off-by: Greg Kroah-Hartman

mac80211: drop A-MSDUs on old ciphers

2021-06-03T06:22:05+00:00

commit 270032a2a9c4535799736142e1e7c413ca7b836e upstream.

With old ciphers (WEP and TKIP) we shouldn't be using A-MSDUs
since A-MSDUs are only supported if we know that they are, and
the only practical way for that is HT support which doesn't
support old ciphers.

However, we would normally accept them anyway. Since we check
the MMIC before deaggregating A-MSDUs, and the A-MSDU bit in
the QoS header is not protected in TKIP (or WEP), this enables
attacks similar to CVE-2020-24588. To prevent that, drop A-MSDUs
completely with old ciphers.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210511200110.076543300172.I548e6e71f1ee9cad4b9a37bf212ae7db723587aa@changeid
Signed-off-by: Johannes Berg 
Signed-off-by: Greg Kroah-Hartman

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: assure all fragments are encrypted

2021-06-03T06:22:04+00:00

commit 965a7d72e798eb7af0aa67210e37cf7ecd1c9cad upstream.

Do not mix plaintext and encrypted fragments in protected Wi-Fi
networks. This fixes CVE-2020-26147.

Previously, an attacker was able to first forward a legitimate encrypted
fragment towards a victim, followed by a plaintext fragment. The
encrypted and plaintext fragment would then be reassembled. For further
details see Section 6.3 and Appendix D in the paper "Fragment and Forge:
Breaking Wi-Fi Through Frame Aggregation and Fragmentation".

Because of this change there are now two equivalent conditions in the
code to determine if a received fragment requires sequential PNs, so we
also move this test to a separate function to make the code easier to
maintain.

Cc: stable@vger.kernel.org
Signed-off-by: Mathy Vanhoef 
Link: https://lore.kernel.org/r/20210511200110.30c4394bb835.I5acfdb552cc1d20c339c262315950b3eac491397@changeid
Signed-off-by: Johannes Berg 
Signed-off-by: Greg Kroah-Hartman

mac80211: clear the beacon's CRC after channel switch

2021-05-22T08:38:27+00:00

[ Upstream commit d6843d1ee283137723b4a8c76244607ce6db1951 ]

After channel switch, we should consider any beacon with a
CSA IE as a new switch. If the CSA IE is a leftover from
before the switch that the AP forgot to remove, we'll get
a CSA-to-Self.

This caused issues in iwlwifi where the firmware saw a beacon
with a CSA-to-Self with mode = 1 on the new channel after a
switch. The firmware considered this a new switch and closed
its queues. Since the beacon didn't change between before and
after the switch, we wouldn't handle it (the CRC is the same)
and we wouldn't let the firmware open its queues again or
disconnect if the CSA IE stays for too long.

Clear the CRC valid state after we switch to make sure that
we handle the beacon and handle the CSA IE as required.

Signed-off-by: Emmanuel Grumbach 
Link: https://lore.kernel.org/r/20210408143124.b9e68aa98304.I465afb55ca2c7d59f7bf610c6046a1fd732b4c28@changeid
Signed-off-by: Johannes Berg 
Signed-off-by: Sasha Levin

mac80211: bail out if cipher schemes are invalid

2021-05-22T08:38:25+00:00

[ Upstream commit db878e27a98106a70315d264cc92230d84009e72 ]

If any of the cipher schemes specified by the driver are invalid, bail
out and fail the registration rather than just warning.  Otherwise, we
might later crash when we try to use the invalid cipher scheme, e.g.
if the hdr_len is (significantly) less than the pn_offs + pn_len, we'd
have an out-of-bounds access in RX validation.

Fixes: 2475b1cc0d52 ("mac80211: add generic cipher scheme support")
Link: https://lore.kernel.org/r/20210408143149.38a3a13a1b19.I6b7f5790fa0958ed8049cf02ac2a535c61e9bc96@changeid
Signed-off-by: Johannes Berg 
Signed-off-by: Sasha Levin