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025bd93f36
From the patch series description: Several security issues in the 802.11 implementations were found by Mathy Vanhoef (New York University Abu Dhabi), who has published all the details at https://papers.mathyvanhoef.com/usenix2021.pdf Specifically, the following CVEs were assigned: * CVE-2020-24586 - Fragmentation cache not cleared on reconnection * CVE-2020-24587 - Reassembling fragments encrypted under different keys * CVE-2020-24588 - Accepting non-SPP A-MSDU frames, which leads to payload being parsed as an L2 frame under an A-MSDU bit toggling attack * CVE-2020-26139 - Forwarding EAPOL from unauthenticated sender * CVE-2020-26140 - Accepting plaintext data frames in protected networks * CVE-2020-26141 - Not verifying TKIP MIC of fragmented frames * CVE-2020-26142 - Processing fragmented frames as full frames * CVE-2020-26143 - Accepting fragmented plaintext frames in protected networks * CVE-2020-26144 - Always accepting unencrypted A-MSDU frames that start with RFC1042 header with EAPOL ethertype * CVE-2020-26145 - Accepting plaintext broadcast fragments as full frames * CVE-2020-26146 - Reassembling encrypted fragments with non-consecutive packet numbers * CVE-2020-26147 - Reassembling mixed encrypted/plaintext fragments In general, the scope of these attacks is that they may allow an attacker to * inject L2 frames that they can more or less control (depending on the vulnerability and attack method) into an otherwise protected network; * exfiltrate (some) network data under certain conditions, this is specific to the fragmentation issues. A subset of these issues is known to apply to the Linux IEEE 802.11 implementation (mac80211). Where it is affected, the attached patches fix the issues, even if not all of them reference the exact CVE IDs. In addition, driver and/or firmware updates may be necessary, as well as potentially more fixes to mac80211, depending on how drivers are using it. Specifically, for Intel devices, firmware needs to be updated to the most recently released versions (which was done without any reference to the security issues) to address some of the vulnerabilities. To have a single set of patches, I'm also including patches for the ath10k and ath11k drivers here. We currently don't have information about how other drivers are, if at all, affected. Signed-off-by: Felix Fietkau <nbd@nbd.name>
70 lines
2.7 KiB
Diff
70 lines
2.7 KiB
Diff
From: Mathy Vanhoef <Mathy.Vanhoef@kuleuven.be>
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Date: Tue, 11 May 2021 20:02:42 +0200
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Subject: [PATCH] mac80211: assure all fragments are encrypted
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Do not mix plaintext and encrypted fragments in protected Wi-Fi
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networks. This fixes CVE-2020-26147.
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Previously, an attacker was able to first forward a legitimate encrypted
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fragment towards a victim, followed by a plaintext fragment. The
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encrypted and plaintext fragment would then be reassembled. For further
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details see Section 6.3 and Appendix D in the paper "Fragment and Forge:
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Breaking Wi-Fi Through Frame Aggregation and Fragmentation".
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Because of this change there are now two equivalent conditions in the
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code to determine if a received fragment requires sequential PNs, so we
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also move this test to a separate function to make the code easier to
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maintain.
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Cc: stable@vger.kernel.org
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Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@kuleuven.be>
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Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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---
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--- a/net/mac80211/rx.c
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+++ b/net/mac80211/rx.c
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@@ -2204,6 +2204,16 @@ ieee80211_reassemble_find(struct ieee802
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return NULL;
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}
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+static bool requires_sequential_pn(struct ieee80211_rx_data *rx, __le16 fc)
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+{
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+ return rx->key &&
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+ (rx->key->conf.cipher == WLAN_CIPHER_SUITE_CCMP ||
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+ rx->key->conf.cipher == WLAN_CIPHER_SUITE_CCMP_256 ||
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+ rx->key->conf.cipher == WLAN_CIPHER_SUITE_GCMP ||
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+ rx->key->conf.cipher == WLAN_CIPHER_SUITE_GCMP_256) &&
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+ ieee80211_has_protected(fc);
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+}
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+
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static ieee80211_rx_result debug_noinline
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ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
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{
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@@ -2248,12 +2258,7 @@ ieee80211_rx_h_defragment(struct ieee802
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/* This is the first fragment of a new frame. */
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entry = ieee80211_reassemble_add(rx->sdata, frag, seq,
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rx->seqno_idx, &(rx->skb));
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- if (rx->key &&
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- (rx->key->conf.cipher == WLAN_CIPHER_SUITE_CCMP ||
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- rx->key->conf.cipher == WLAN_CIPHER_SUITE_CCMP_256 ||
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- rx->key->conf.cipher == WLAN_CIPHER_SUITE_GCMP ||
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- rx->key->conf.cipher == WLAN_CIPHER_SUITE_GCMP_256) &&
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- ieee80211_has_protected(fc)) {
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+ if (requires_sequential_pn(rx, fc)) {
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int queue = rx->security_idx;
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/* Store CCMP/GCMP PN so that we can verify that the
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@@ -2295,11 +2300,7 @@ ieee80211_rx_h_defragment(struct ieee802
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u8 pn[IEEE80211_CCMP_PN_LEN], *rpn;
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int queue;
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- if (!rx->key ||
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- (rx->key->conf.cipher != WLAN_CIPHER_SUITE_CCMP &&
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- rx->key->conf.cipher != WLAN_CIPHER_SUITE_CCMP_256 &&
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- rx->key->conf.cipher != WLAN_CIPHER_SUITE_GCMP &&
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- rx->key->conf.cipher != WLAN_CIPHER_SUITE_GCMP_256))
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+ if (!requires_sequential_pn(rx, fc))
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return RX_DROP_UNUSABLE;
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memcpy(pn, entry->last_pn, IEEE80211_CCMP_PN_LEN);
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for (i = IEEE80211_CCMP_PN_LEN - 1; i >= 0; i--) {
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