[PATCH net 6/6] netfilter: nft_meta: use skb_to_full_sk() helper

[Eric Dumazet]

SYNACK packets might be attached to request sockets.

Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of 
listener")
Signed-off-by: Eric Dumazet <eduma...@google.com>
---
 net/netfilter/nft_meta.c | 36 ++++++++++++++++++++----------------
 1 file changed, 20 insertions(+), 16 deletions(-)

diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c
index e4ad2c24bc41..9dfaf4d55ee0 100644
--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -31,6 +31,7 @@ void nft_meta_get_eval(const struct nft_expr *expr,
        const struct nft_meta *priv = nft_expr_priv(expr);
        const struct sk_buff *skb = pkt->skb;
        const struct net_device *in = pkt->in, *out = pkt->out;
+       struct sock *sk;
        u32 *dest = &regs->data[priv->dreg];
 
        switch (priv->key) {
@@ -86,33 +87,35 @@ void nft_meta_get_eval(const struct nft_expr *expr,
                *(u16 *)dest = out->type;
                break;
        case NFT_META_SKUID:
-               if (skb->sk == NULL || !sk_fullsock(skb->sk))
+               sk = skb_to_full_sk(skb);
+               if (!sk || !sk_fullsock(sk))
                        goto err;
 
-               read_lock_bh(&skb->sk->sk_callback_lock);
-               if (skb->sk->sk_socket == NULL ||
-                   skb->sk->sk_socket->file == NULL) {
-                       read_unlock_bh(&skb->sk->sk_callback_lock);
+               read_lock_bh(&sk->sk_callback_lock);
+               if (sk->sk_socket == NULL ||
+                   sk->sk_socket->file == NULL) {
+                       read_unlock_bh(&sk->sk_callback_lock);
                        goto err;
                }
 
                *dest = from_kuid_munged(&init_user_ns,
-                               skb->sk->sk_socket->file->f_cred->fsuid);
-               read_unlock_bh(&skb->sk->sk_callback_lock);
+                               sk->sk_socket->file->f_cred->fsuid);
+               read_unlock_bh(&sk->sk_callback_lock);
                break;
        case NFT_META_SKGID:
-               if (skb->sk == NULL || !sk_fullsock(skb->sk))
+               sk = skb_to_full_sk(skb);
+               if (!sk || !sk_fullsock(sk))
                        goto err;
 
-               read_lock_bh(&skb->sk->sk_callback_lock);
-               if (skb->sk->sk_socket == NULL ||
-                   skb->sk->sk_socket->file == NULL) {
-                       read_unlock_bh(&skb->sk->sk_callback_lock);
+               read_lock_bh(&sk->sk_callback_lock);
+               if (sk->sk_socket == NULL ||
+                   sk->sk_socket->file == NULL) {
+                       read_unlock_bh(&sk->sk_callback_lock);
                        goto err;
                }
                *dest = from_kgid_munged(&init_user_ns,
-                                skb->sk->sk_socket->file->f_cred->fsgid);
-               read_unlock_bh(&skb->sk->sk_callback_lock);
+                                sk->sk_socket->file->f_cred->fsgid);
+               read_unlock_bh(&sk->sk_callback_lock);
                break;
 #ifdef CONFIG_IP_ROUTE_CLASSID
        case NFT_META_RTCLASSID: {
@@ -168,9 +171,10 @@ void nft_meta_get_eval(const struct nft_expr *expr,
                break;
 #ifdef CONFIG_CGROUP_NET_CLASSID
        case NFT_META_CGROUP:
-               if (skb->sk == NULL || !sk_fullsock(skb->sk))
+               sk = skb_to_full_sk(skb);
+               if (!sk || !sk_fullsock(sk))
                        goto err;
-               *dest = skb->sk->sk_classid;
+               *dest = sk->sk_classid;
                break;
 #endif
        default:
-- 
2.6.0.rc2.230.g3dd15c0

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