On 17/01/2025 18:14, Sabrina Dubroca wrote:
2025-01-13, 10:31:31 +0100, Antonio Quartulli wrote:+static int ovpn_tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, + int flags, int *addr_len) +{ + int err = 0, off, copied = 0, ret; + struct ovpn_socket *sock; + struct ovpn_peer *peer; + struct sk_buff *skb; + + rcu_read_lock(); + sock = rcu_dereference_sk_user_data(sk); + if (!sock || !sock->peer) { + rcu_read_unlock(); + return -EBADF; + } + /* we take a reference to the peer linked to this TCP socket, because + * in turn the peer holds a reference to the socket itself.
Going back now to this specific comment:
Not anymore since v12? [*] I think it's ok here because we're only using peer and sk (not anything from ovpn_socket), but it is relevant in _sendmsg, which has the same peer_hold pattern without this comment.
After applying to _sendmsg() the modifications you suggested (i.e. reference peer directly instead of sock->peer), it also only uses peer and sk, but not ovpn_socket.
Therefore it should be fine too. This said, the comment above should go away or at least should be modified.
[*] v11: - https://lore.kernel.org/netdev/20241029-b4-ovpn-v11-8-de4698c73a25@xxxxxxxxxxx/ ovpn_peer_release -> ovpn_socket_put v12: - https://lore.kernel.org/netdev/20241202-b4-ovpn-v12-9-239ff733bf97@xxxxxxxxxxx/ ovpn_peer_release doesn't do ovpn_socket_put - https://lore.kernel.org/netdev/20241202-b4-ovpn-v12-7-239ff733bf97@xxxxxxxxxxx/ ovpn_socket_put is done directly at ovpn_peer_remove time, before the final peer_put
Right - the lifetime of ovpn_socket is not tied to ovpn_peer anymore. However, with the current code I don't think we ever assume that. Regards, -- Antonio Quartulli OpenVPN Inc.
