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From: Cong Wang <xiyou.wangcong@gmail.com>
To: netdev@vger.kernel.org
Cc: bpf@vger.kernel.org, Cong Wang <cong.wang@bytedance.com>,
	John Fastabend <john.fastabend@gmail.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Jakub Sitnicki <jakub@cloudflare.com>,
	Lorenz Bauer <lmb@cloudflare.com>
Subject: [Patch bpf v2 1/4] skmsg: introduce sk_psock_get_checked()
Date: Mon, 27 Sep 2021 17:22:09 -0700	[thread overview]
Message-ID: <20210928002212.14498-2-xiyou.wangcong@gmail.com> (raw)
In-Reply-To: <20210928002212.14498-1-xiyou.wangcong@gmail.com>

From: Cong Wang <cong.wang@bytedance.com>

Although we have sk_psock_get(), it assumes the psock
retrieved from sk_user_data is for sockmap, this is not
sufficient if we call it outside of sockmap, for example,
reuseport_array.

Fortunately sock_map_psock_get_checked() is more strict
and checks for sock_map_close before using psock. So we can
refactor it and rename it to sk_psock_get_checked(), which
can be safely called outside of sockmap.

Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jakub Sitnicki <jakub@cloudflare.com>
Cc: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
---
 include/linux/skmsg.h | 20 ++++++++++++++++++++
 net/core/sock_map.c   | 22 +---------------------
 2 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 14ab0c0bc924..8f577739fc36 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -452,6 +452,26 @@ static inline struct sk_psock *sk_psock_get(struct sock *sk)
 	return psock;
 }
 
+static inline struct sk_psock *sk_psock_get_checked(struct sock *sk)
+{
+	struct sk_psock *psock;
+
+	rcu_read_lock();
+	psock = sk_psock(sk);
+	if (psock) {
+#if defined(CONFIG_BPF_SYSCALL)
+		if (sk->sk_prot->close != sock_map_close) {
+			rcu_read_unlock();
+			return ERR_PTR(-EBUSY);
+		}
+#endif
+		if (!refcount_inc_not_zero(&psock->refcnt))
+			psock = ERR_PTR(-EBUSY);
+	}
+	rcu_read_unlock();
+	return psock;
+}
+
 void sk_psock_drop(struct sock *sk, struct sk_psock *psock);
 
 static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index e252b8ec2b85..6612bb0b95b5 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -191,26 +191,6 @@ static int sock_map_init_proto(struct sock *sk, struct sk_psock *psock)
 	return sk->sk_prot->psock_update_sk_prot(sk, psock, false);
 }
 
-static struct sk_psock *sock_map_psock_get_checked(struct sock *sk)
-{
-	struct sk_psock *psock;
-
-	rcu_read_lock();
-	psock = sk_psock(sk);
-	if (psock) {
-		if (sk->sk_prot->close != sock_map_close) {
-			psock = ERR_PTR(-EBUSY);
-			goto out;
-		}
-
-		if (!refcount_inc_not_zero(&psock->refcnt))
-			psock = ERR_PTR(-EBUSY);
-	}
-out:
-	rcu_read_unlock();
-	return psock;
-}
-
 static int sock_map_link(struct bpf_map *map, struct sock *sk)
 {
 	struct sk_psock_progs *progs = sock_map_progs(map);
@@ -255,7 +235,7 @@ static int sock_map_link(struct bpf_map *map, struct sock *sk)
 		}
 	}
 
-	psock = sock_map_psock_get_checked(sk);
+	psock = sk_psock_get_checked(sk);
 	if (IS_ERR(psock)) {
 		ret = PTR_ERR(psock);
 		goto out_progs;
-- 
2.30.2


  reply	other threads:[~2021-09-28  0:22 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-28  0:22 [Patch bpf v2 0/4] sock_map: fix ->poll() and update selftests Cong Wang
2021-09-28  0:22 ` Cong Wang [this message]
2021-09-28  0:22 ` [Patch bpf v2 2/4] net: rename ->stream_memory_read to ->sock_is_readable Cong Wang
2021-09-28  0:22 ` [Patch bpf v2 3/4] net: implement ->sock_is_readable for UDP and AF_UNIX Cong Wang
2021-09-30 21:44   ` John Fastabend
2021-10-02  0:00     ` Cong Wang
2021-09-28  0:22 ` [Patch bpf v2 4/4] selftests/bpf: use recv_timeout() instead of retries Cong Wang

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