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Commit 56eeeb79 authored by Mathy Vanhoef's avatar Mathy Vanhoef Committed by Greg Kroah-Hartman
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mac80211: properly handle A-MSDUs that start with an RFC 1042 header 



commit a1d5ff5651ea592c67054233b14b30bf4452999c upstream.

Properly parse A-MSDUs whose first 6 bytes happen to equal a rfc1042
header. This can occur in practice when the destination MAC address
equals AA:AA:03:00:00:00. More importantly, this simplifies the next
patch to mitigate A-MSDU injection attacks.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarMathy Vanhoef <Mathy.Vanhoef@kuleuven.be>
Link: https://lore.kernel.org/r/20210511200110.0b2b886492f0.I23dd5d685fe16d3b0ec8106e8f01b59f499dffed@changeid


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent bb474664

include/net/cfg80211.h

+3 −2
Original line number Diff line number Diff line
@@ -4056,7 +4056,8 @@ unsigned int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr); 
 * Return: 0 on success. Non-zero on error.

 */

int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr,

				  const u8 *addr, enum nl80211_iftype iftype);

				  const u8 *addr, enum nl80211_iftype iftype,

				  bool is_amsdu);



/**

 * ieee80211_data_to_8023 - convert an 802.11 data frame to 802.3
@@ -4068,7 +4069,7 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr, 
static inline int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,

					 enum nl80211_iftype iftype)

{

	return ieee80211_data_to_8023_exthdr(skb, NULL, addr, iftype);

	return ieee80211_data_to_8023_exthdr(skb, NULL, addr, iftype, false);

}



/**

net/mac80211/rx.c

+2 −1
Original line number Diff line number Diff line
@@ -2428,7 +2428,8 @@ ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx) 


	if (ieee80211_data_to_8023_exthdr(skb, &ethhdr,

					  rx->sdata->vif.addr,

					  rx->sdata->vif.type))

					  rx->sdata->vif.type,

					  true))

		return RX_DROP_UNUSABLE;



	ieee80211_amsdu_to_8023s(skb, &frame_list, dev->dev_addr,

net/wireless/util.c

+3 −2
Original line number Diff line number Diff line
@@ -421,7 +421,8 @@ unsigned int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr) 
EXPORT_SYMBOL(ieee80211_get_mesh_hdrlen);



int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr,

				  const u8 *addr, enum nl80211_iftype iftype)

				  const u8 *addr, enum nl80211_iftype iftype,

				  bool is_amsdu)

{

	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;

	struct {
@@ -509,7 +510,7 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr, 
	skb_copy_bits(skb, hdrlen, &payload, sizeof(payload));

	tmp.h_proto = payload.proto;



	if (likely((ether_addr_equal(payload.hdr, rfc1042_header) &&

	if (likely((!is_amsdu && ether_addr_equal(payload.hdr, rfc1042_header) &&

		    tmp.h_proto != htons(ETH_P_AARP) &&

		    tmp.h_proto != htons(ETH_P_IPX)) ||

		   ether_addr_equal(payload.hdr, bridge_tunnel_header)))