From: Mathy Vanhoef <Mathy.Vanhoef@xxxxxxxxxxx> 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@xxxxxxxxxxxxxxx Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@xxxxxxxxxxx> Link: https://lore.kernel.org/r/20210511200110.0b2b886492f0.I23dd5d685fe16d3b0ec8106e8f01b59f499dffed@changeid Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> --- 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 28a0d7a8c142..ba388549b38c 100644 --- a/include/net/cfg80211.h +++ b/include/net/cfg80211.h @@ -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); } /** diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index d3aee2859f0a..6c54941a3265 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -2428,7 +2428,8 @@ 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 262922cf6a0c..8c67b7cf1def 100644 --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -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))) -- 2.31.1
