2022-10-07 13:00:13

by Felix Fietkau

Subject: [PATCH v2 6.1 1/2] wifi: cfg80211: fix ieee80211_data_to_8023_exthdr handling of small packets

STP topology change notification packets only have a payload of 7 bytes,
so they get dropped due to the skb->len < hdrlen + 8 check.
Fix this by removing skb->len based checks and instead check the return code
on the skb_copy_bits calls.

Fixes: 2d1c304cb2d5 ("cfg80211: add function for 802.3 conversion with separate output buffer")
Reported-by: Chad Monroe <[email protected]>
Signed-off-by: Felix Fietkau <[email protected]>
---
net/wireless/util.c | 40 +++++++++++++++++++++-------------------
1 file changed, 21 insertions(+), 19 deletions(-)

diff --git a/net/wireless/util.c b/net/wireless/util.c
index 01493568a21d..1f285b515028 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -559,7 +559,7 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr,
return -1;

hdrlen = ieee80211_hdrlen(hdr->frame_control) + data_offset;
- if (skb->len < hdrlen + 8)
+ if (skb->len < hdrlen)
return -1;

/* convert IEEE 802.11 header + possible LLC headers into Ethernet
@@ -574,8 +574,9 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr,
memcpy(tmp.h_dest, ieee80211_get_DA(hdr), ETH_ALEN);
memcpy(tmp.h_source, ieee80211_get_SA(hdr), ETH_ALEN);

- if (iftype == NL80211_IFTYPE_MESH_POINT)
- skb_copy_bits(skb, hdrlen, &mesh_flags, 1);
+ if (iftype == NL80211_IFTYPE_MESH_POINT &&
+ skb_copy_bits(skb, hdrlen, &mesh_flags, 1) < 0)
+ return -1;

mesh_flags &= MESH_FLAGS_AE;

@@ -595,11 +596,12 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr,
if (iftype == NL80211_IFTYPE_MESH_POINT) {
if (mesh_flags == MESH_FLAGS_AE_A4)
return -1;
- if (mesh_flags == MESH_FLAGS_AE_A5_A6) {
- skb_copy_bits(skb, hdrlen +
- offsetof(struct ieee80211s_hdr, eaddr1),
- tmp.h_dest, 2 * ETH_ALEN);
- }
+ if (mesh_flags == MESH_FLAGS_AE_A5_A6 &&
+ skb_copy_bits(skb, hdrlen +
+ offsetof(struct ieee80211s_hdr, eaddr1),
+ tmp.h_dest, 2 * ETH_ALEN) < 0)
+ return -1;
+
hdrlen += __ieee80211_get_mesh_hdrlen(mesh_flags);
}
break;
@@ -613,10 +615,11 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr,
if (iftype == NL80211_IFTYPE_MESH_POINT) {
if (mesh_flags == MESH_FLAGS_AE_A5_A6)
return -1;
- if (mesh_flags == MESH_FLAGS_AE_A4)
- skb_copy_bits(skb, hdrlen +
- offsetof(struct ieee80211s_hdr, eaddr1),
- tmp.h_source, ETH_ALEN);
+ if (mesh_flags == MESH_FLAGS_AE_A4 &&
+ skb_copy_bits(skb, hdrlen +
+ offsetof(struct ieee80211s_hdr, eaddr1),
+ tmp.h_source, ETH_ALEN) < 0)
+ return -1;
hdrlen += __ieee80211_get_mesh_hdrlen(mesh_flags);
}
break;
@@ -628,16 +631,15 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr,
break;
}

- skb_copy_bits(skb, hdrlen, &payload, sizeof(payload));
- tmp.h_proto = payload.proto;
-
- 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))) {
+ if (likely(skb_copy_bits(skb, hdrlen, &payload, sizeof(payload)) == 0 &&
+ ((!is_amsdu && ether_addr_equal(payload.hdr, rfc1042_header) &&
+ payload.proto != htons(ETH_P_AARP) &&
+ payload.proto != htons(ETH_P_IPX)) ||
+ ether_addr_equal(payload.hdr, bridge_tunnel_header)))) {
/* remove RFC1042 or Bridge-Tunnel encapsulation and
* replace EtherType */
hdrlen += ETH_ALEN + 2;
+ tmp.h_proto = payload.proto;
skb_postpull_rcsum(skb, &payload, ETH_ALEN + 2);
} else {
tmp.h_proto = htons(skb->len - hdrlen);
--
2.36.1

2022-10-07 13:00:28

by Felix Fietkau

Subject: [PATCH v2 6.1 2/2] wifi: mac80211: do not drop packets smaller than the LLC-SNAP header on fast-rx

Since STP TCN frames are only 7 bytes, the pskb_may_pull call returns an error.
Instead of dropping those packets, bump them back to the slow path for proper
processing.

Fixes: 49ddf8e6e234 ("mac80211: add fast-rx path")
Reported-by: Chad Monroe <[email protected]>
Signed-off-by: Felix Fietkau <[email protected]>
---
net/mac80211/rx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 9183e5f1ad29..589521717c35 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -4709,7 +4709,7 @@ static bool ieee80211_invoke_fast_rx(struct ieee80211_rx_data *rx,

if (!(status->rx_flags & IEEE80211_RX_AMSDU)) {
if (!pskb_may_pull(skb, snap_offs + sizeof(*payload)))
- goto drop;
+ return false;

payload = (void *)(skb->data + snap_offs);

--
2.36.1