mac80211: backport upstream fixes for FragAttacks

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>

1 files changed, 109 insertions, 0 deletions

diff --git a/package/kernel/mac80211/patches/ath/305-ath10k-Validate-first-subframe-of-A-MSDU-before-proc.patch b/package/kernel/mac80211/patches/ath/305-ath10k-Validate-first-subframe-of-A-MSDU-before-proc.patch
new file mode 100644
index 0000000000..0bdbed78d5
--- /dev/null
+++ b/package/kernel/mac80211/patches/ath/305-ath10k-Validate-first-subframe-of-A-MSDU-before-proc.patch
@@ -0,0 +1,109 @@
+From: Sriram R <srirrama@codeaurora.org>
+Date: Tue, 11 May 2021 20:02:57 +0200
+Subject: [PATCH] ath10k: Validate first subframe of A-MSDU before
+ processing the list
+
+In certain scenarios a normal MSDU can be received as an A-MSDU when
+the A-MSDU present bit of a QoS header gets flipped during reception.
+Since this bit is unauthenticated, the hardware crypto engine can pass
+the frame to the driver without any error indication.
+
+This could result in processing unintended subframes collected in the
+A-MSDU list. Hence, validate A-MSDU list by checking if the first frame
+has a valid subframe header.
+
+Comparing the non-aggregated MSDU and an A-MSDU, the fields of the first
+subframe DA matches the LLC/SNAP header fields of a normal MSDU.
+In order to avoid processing such frames, add a validation to
+filter such A-MSDU frames where the first subframe header DA matches
+with the LLC/SNAP header pattern.
+
+Tested-on: QCA9984 hw1.0 PCI 10.4-3.10-00047
+
+Cc: stable@vger.kernel.org
+Signed-off-by: Sriram R <srirrama@codeaurora.org>
+Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
+Signed-off-by: Johannes Berg <johannes.berg@intel.com>
+---
+
+--- a/drivers/net/wireless/ath/ath10k/htt_rx.c
++++ b/drivers/net/wireless/ath/ath10k/htt_rx.c
+@@ -2108,14 +2108,62 @@ static void ath10k_htt_rx_h_unchain(stru
+ 	ath10k_unchain_msdu(amsdu, unchain_cnt);
+ }
+ 
++static bool ath10k_htt_rx_validate_amsdu(struct ath10k *ar,
++					 struct sk_buff_head *amsdu)
++{
++	u8 *subframe_hdr;
++	struct sk_buff *first;
++	bool is_first, is_last;
++	struct htt_rx_desc *rxd;
++	struct ieee80211_hdr *hdr;
++	size_t hdr_len, crypto_len;
++	enum htt_rx_mpdu_encrypt_type enctype;
++	int bytes_aligned = ar->hw_params.decap_align_bytes;
++
++	first = skb_peek(amsdu);
++
++	rxd = (void *)first->data - sizeof(*rxd);
++	hdr = (void *)rxd->rx_hdr_status;
++
++	is_first = !!(rxd->msdu_end.common.info0 &
++		      __cpu_to_le32(RX_MSDU_END_INFO0_FIRST_MSDU));
++	is_last = !!(rxd->msdu_end.common.info0 &
++		     __cpu_to_le32(RX_MSDU_END_INFO0_LAST_MSDU));
++
++	/* Return in case of non-aggregated msdu */
++	if (is_first && is_last)
++		return true;
++
++	/* First msdu flag is not set for the first msdu of the list */
++	if (!is_first)
++		return false;
++
++	enctype = MS(__le32_to_cpu(rxd->mpdu_start.info0),
++		     RX_MPDU_START_INFO0_ENCRYPT_TYPE);
++
++	hdr_len = ieee80211_hdrlen(hdr->frame_control);
++	crypto_len = ath10k_htt_rx_crypto_param_len(ar, enctype);
++
++	subframe_hdr = (u8 *)hdr + round_up(hdr_len, bytes_aligned) +
++		       crypto_len;
++
++	/* Validate if the amsdu has a proper first subframe.
++	 * There are chances a single msdu can be received as amsdu when
++	 * the unauthenticated amsdu flag of a QoS header
++	 * gets flipped in non-SPP AMSDU's, in such cases the first
++	 * subframe has llc/snap header in place of a valid da.
++	 * return false if the da matches rfc1042 pattern
++	 */
++	if (ether_addr_equal(subframe_hdr, rfc1042_header))
++		return false;
++
++	return true;
++}
++
+ static bool ath10k_htt_rx_amsdu_allowed(struct ath10k *ar,
+ 					struct sk_buff_head *amsdu,
+ 					struct ieee80211_rx_status *rx_status)
+ {
+-	/* FIXME: It might be a good idea to do some fuzzy-testing to drop
+-	 * invalid/dangerous frames.
+-	 */
+-
+ 	if (!rx_status->freq) {
+ 		ath10k_dbg(ar, ATH10K_DBG_HTT, "no channel configured; ignoring frame(s)!\n");
+ 		return false;
+@@ -2126,6 +2174,11 @@ static bool ath10k_htt_rx_amsdu_allowed(
+ 		return false;
+ 	}
+ 
++	if (!ath10k_htt_rx_validate_amsdu(ar, amsdu)) {
++		ath10k_dbg(ar, ATH10K_DBG_HTT, "invalid amsdu received\n");
++		return false;
++	}
++
+ 	return true;
+ }
+