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From: Jakub Sitnicki <jakub@cloudflare.com>
To: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org, kernel-team@cloudflare.com,
	Martin KaFai Lau <kafai@fb.com>
Subject: [PATCH bpf-next v5 04/12] tcp_bpf: Don't let child socket inherit parent protocol ops on copy
Date: Mon, 27 Jan 2020 13:55:26 +0100	[thread overview]
Message-ID: <20200127125534.137492-5-jakub@cloudflare.com> (raw)
In-Reply-To: <20200127125534.137492-1-jakub@cloudflare.com>

Prepare for cloning listening sockets that have their protocol callbacks
overridden by sk_msg. Child sockets must not inherit parent callbacks that
access state stored in sk_user_data owned by the parent.

Restore the child socket protocol callbacks before it gets hashed and any
of the callbacks can get invoked.

Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
---
 include/net/tcp.h        |  7 +++++++
 net/ipv4/tcp_bpf.c       | 13 +++++++++++++
 net/ipv4/tcp_minisocks.c |  2 ++
 3 files changed, 22 insertions(+)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index a5ea27df3c2b..07f947cc80e6 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -2203,6 +2203,13 @@ int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 		    int nonblock, int flags, int *addr_len);
 int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock,
 		      struct msghdr *msg, int len, int flags);
+#ifdef CONFIG_NET_SOCK_MSG
+void tcp_bpf_clone(const struct sock *sk, struct sock *newsk);
+#else
+static inline void tcp_bpf_clone(const struct sock *sk, struct sock *newsk)
+{
+}
+#endif
 
 /* Call BPF_SOCK_OPS program that returns an int. If the return value
  * is < 0, then the BPF op failed (for example if the loaded BPF
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index dd183b050642..c0439c015341 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -579,6 +579,19 @@ static void tcp_bpf_close(struct sock *sk, long timeout)
 	saved_close(sk, timeout);
 }
 
+/* If a child got cloned from a listening socket that had tcp_bpf
+ * protocol callbacks installed, we need to restore the callbacks to
+ * the default ones because the child does not inherit the psock state
+ * that tcp_bpf callbacks expect.
+ */
+void tcp_bpf_clone(const struct sock *sk, struct sock *newsk)
+{
+	struct proto *prot = newsk->sk_prot;
+
+	if (prot->unhash == tcp_bpf_unhash)
+		newsk->sk_prot = sk->sk_prot_creator;
+}
+
 enum {
 	TCP_BPF_IPV4,
 	TCP_BPF_IPV6,
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index ad3b56d9fa71..c8274371c3d0 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -548,6 +548,8 @@ struct sock *tcp_create_openreq_child(const struct sock *sk,
 	newtp->fastopen_req = NULL;
 	RCU_INIT_POINTER(newtp->fastopen_rsk, NULL);
 
+	tcp_bpf_clone(sk, newsk);
+
 	__TCP_INC_STATS(sock_net(sk), TCP_MIB_PASSIVEOPENS);
 
 	return newsk;
-- 
2.24.1


  parent reply	other threads:[~2020-01-27 12:55 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-27 12:55 [PATCH bpf-next v5 00/12] Extend SOCKMAP to store listening sockets Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 01/12] bpf, sk_msg: Don't clear saved sock proto on restore Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 02/12] net, sk_msg: Annotate lockless access to sk_prot on clone Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 03/12] net, sk_msg: Clear sk_user_data pointer on clone if tagged Jakub Sitnicki
2020-01-27 12:55 ` Jakub Sitnicki [this message]
2020-01-27 12:55 ` [PATCH bpf-next v5 05/12] bpf, sockmap: Allow inserting listening TCP sockets into sockmap Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 06/12] bpf, sockmap: Don't set up sockmap progs for listening sockets Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 07/12] bpf, sockmap: Return socket cookie on lookup from syscall Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 08/12] bpf, sockmap: Let all kernel-land lookup values in SOCKMAP Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 09/12] bpf: Allow selecting reuseport socket from a SOCKMAP Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 10/12] net: Generate reuseport group ID on group creation Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 11/12] selftests/bpf: Extend SK_REUSEPORT tests to cover SOCKMAP Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 12/12] selftests/bpf: Tests for SOCKMAP holding listening sockets Jakub Sitnicki
2020-03-11 18:48   ` Andrii Nakryiko
2020-03-11 19:49     ` Jakub Sitnicki
2020-03-11 21:02       ` Andrii Nakryiko
2020-03-12 17:25         ` Jakub Sitnicki
2020-01-27 13:01 ` [PATCH bpf-next v5 00/12] Extend SOCKMAP to store " Jakub Sitnicki
2020-01-27 13:05 ` Jakub Sitnicki

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