From e80251555f0befd1271e74b080bccf0ff0348bfc Mon Sep 17 00:00:00 2001 From: Jakub Sitnicki Date: Tue, 18 Feb 2020 17:10:15 +0000 Subject: 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 Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200218171023.844439-4-jakub@cloudflare.com --- net/ipv4/tcp_bpf.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'net/ipv4/tcp_bpf.c') 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; +} -- cgit