[PATCH v4.14 03/10] mac80211: properly handle A-MSDUs that start with an RFC 1042 header
From: Johannes Berg <johannes@sipsolutions.net>
Date: 2021-05-31 20:31:51
Also in:
stable
Subsystem:
802.11 (including cfg80211/nl80211), mac80211, the rest · Maintainers:
Johannes Berg, Linus Torvalds
From: Mathy Vanhoef <redacted> 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: Mathy Vanhoef <redacted> Link: https://lore.kernel.org/r/20210511200110.0b2b886492f0.I23dd5d685fe16d3b0ec8106e8f01b59f499dffed@changeid (local) Signed-off-by: Johannes Berg <redacted> --- include/net/cfg80211.h | 5 +++-- net/mac80211/rx.c | 3 ++- net/wireless/util.c | 5 +++-- 3 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 030eea38f258..be161f82abc6 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h@@ -4338,7 +4338,8 @@ 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
@@ -4350,7 +4351,7 @@ 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); } /**
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 8c126854aa06..be7e37edad12 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c@@ -2451,7 +2451,8 @@ ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx) if (ieee80211_data_to_8023_exthdr(skb, ðhdr, 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,
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 935929b45411..2aef1c487be6 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c@@ -422,7 +422,8 @@ 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 {
@@ -510,7 +511,7 @@ 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)))
--
2.31.1