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authorJakub Sitnicki <jakub@cloudflare.com>2020-02-18 17:10:15 +0000
committerDaniel Borkmann <daniel@iogearbox.net>2020-02-21 22:29:45 +0100
commite80251555f0befd1271e74b080bccf0ff0348bfc (patch)
tree3387dd45af325c1929a160a8fab7b84dd0142e08 /net
parentf1ff5ce2cd5ef3335f19c0f6576582c87045b04f (diff)
tcp_bpf: Don't let child socket inherit parent protocol ops on copy
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. Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200218171023.844439-4-jakub@cloudflare.com
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp_bpf.c14
-rw-r--r--net/ipv4/tcp_minisocks.c2
2 files changed, 16 insertions, 0 deletions
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index dd183b050642..7d6e1b75d4d4 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -693,3 +693,17 @@ int tcp_bpf_init(struct sock *sk)
rcu_read_unlock();
return 0;
}
+
+/* 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)
+{
+ int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4;
+ struct proto *prot = newsk->sk_prot;
+
+ if (prot == &tcp_bpf_prots[family][TCP_BPF_BASE])
+ newsk->sk_prot = sk->sk_prot_creator;
+}
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;