[PATCH] wifi: add sk_requests_wifi_status()

[Bert Karwatzki <spasswolf@web.de>]

Checking the SOCK_WIFI_STATUS flag bit in sk_flags, may give a wrong result
since sk_flags are part of a union and the union is used otherwise. Add
a sk_requests_wifi_status() which checks if sk is non-NULL, sk is a full socket
and checks the flag bit.

Fixes: 76a853f86c97 ("wifi: free SKBTX_WIFI_STATUS skb tx_flags flag")
Idea-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Bert Karwatzki <spasswolf@web.de>
---
 drivers/net/wireless/ath/wil6210/txrx.h     | 3 +--
 drivers/net/wireless/marvell/mwifiex/main.c | 3 +--
 include/net/sock.h                          | 7 +++++++
 net/mac80211/mesh.c                         | 2 +-
 net/mac80211/tx.c                           | 6 +++---
 5 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/ath/wil6210/txrx.h b/drivers/net/wireless/ath/wil6210/txrx.h
index 33ccd0b248d4..fff8b7f8abc5 100644
--- a/drivers/net/wireless/ath/wil6210/txrx.h
+++ b/drivers/net/wireless/ath/wil6210/txrx.h
@@ -617,8 +617,7 @@ static inline bool wil_need_txstat(struct sk_buff *skb)
 {
 	const u8 *da = wil_skb_get_da(skb);
 
-	return is_unicast_ether_addr(da) && skb->sk &&
-	       sock_flag(skb->sk, SOCK_WIFI_STATUS);
+	return is_unicast_ether_addr(da) && sk_requests_wifi_status(skb->sk);
 }
 
 static inline void wil_consume_skb(struct sk_buff *skb, bool acked)
diff --git a/drivers/net/wireless/marvell/mwifiex/main.c b/drivers/net/wireless/marvell/mwifiex/main.c
index 1485f949ad4e..7b50a88a18e5 100644
--- a/drivers/net/wireless/marvell/mwifiex/main.c
+++ b/drivers/net/wireless/marvell/mwifiex/main.c
@@ -913,8 +913,7 @@ mwifiex_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	multicast = is_multicast_ether_addr(skb->data);
 
-	if (unlikely(!multicast && skb->sk &&
-		     sock_flag(skb->sk, SOCK_WIFI_STATUS) &&
+	if (unlikely(!multicast && sk_requests_wifi_status(skb->sk) &&
 		     priv->adapter->fw_api_ver == MWIFIEX_FW_V15))
 		skb = mwifiex_clone_skb_for_tx_status(priv,
 						      skb,
diff --git a/include/net/sock.h b/include/net/sock.h
index 3e15d7105ad2..2da289ec4c17 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2822,6 +2822,13 @@ sk_is_refcounted(struct sock *sk)
 	return !sk_fullsock(sk) || !sock_flag(sk, SOCK_RCU_FREE);
 }
 
+static inline bool
+sk_requests_wifi_status(struct sock *sk)
+{
+	return sk && sk_fullsock(sk) && sock_flag(sk,
+SOCK_WIFI_STATUS);
+}
+
 /* Checks if this SKB belongs to an HW offloaded socket
  * and whether any SW fallbacks are required based on dev.
  * Check decrypted mark in case skb_orphan() cleared socket.
diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c
index a381b4b756ea..5cc56d578048 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -777,7 +777,7 @@ bool ieee80211_mesh_xmit_fast(struct ieee80211_sub_if_data *sdata,
 	if (ethertype < ETH_P_802_3_MIN)
 		return false;
 
-	if (skb->sk && sock_flag(skb->sk, SOCK_WIFI_STATUS))
+	if (sk_requests_wifi_status(skb->sk))
 		return false;
 
 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 3b9392a6ddb2..d8d4f3d7d7f2 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -2859,7 +2859,7 @@ static struct sk_buff *ieee80211_build_hdr(struct ieee80211_sub_if_data *sdata,
 	}
 
 	if (unlikely(!multicast &&
-		     ((skb->sk && sock_flag(skb->sk, SOCK_WIFI_STATUS)) ||
+		     (sk_requests_wifi_status(skb->sk) ||
 		      ctrl_flags & IEEE80211_TX_CTL_REQ_TX_STATUS)))
 		info_id = ieee80211_store_ack_skb(local, skb, &info_flags,
 						  cookie);
@@ -3756,7 +3756,7 @@ static bool ieee80211_xmit_fast(struct ieee80211_sub_if_data *sdata,
 		return false;
 
 	/* don't handle TX status request here either */
-	if (skb->sk && sock_flag(skb->sk, SOCK_WIFI_STATUS))
+	if (sk_requests_wifi_status(skb->sk))
 		return false;
 
 	if (hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_QOS_DATA)) {
@@ -4648,7 +4648,7 @@ static void ieee80211_8023_xmit(struct ieee80211_sub_if_data *sdata,
 			memcpy(IEEE80211_SKB_CB(seg), info, sizeof(*info));
 	}
 
-	if (unlikely(skb->sk && sock_flag(skb->sk, SOCK_WIFI_STATUS))) {
+	if (unlikely(sk_requests_wifi_status(skb->sk))) {
 		info->status_data = ieee80211_store_ack_skb(local, skb,
 							    &info->flags, NULL);
 		if (info->status_data)
-- 
2.49.0

There are two calls to sock_flag(., SOCK_WIFI_STATUS) which I didn't change:
In __sock_recv_wifi_status() (in net/socket.c) which gets called by 
sock_recv_timestamp() and in sk_getsockopt() (in net/core/sock.c). These
existed before the error occured and seem to be fine. 

Bert Karwatzki