4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Daniel Borkmann daniel@iogearbox.net
[ Upstream commit 90545cdc3f2b2ea700e24335610cd181e73756da ]
I found that in BPF sockmap programs once we either delete a socket from the map or we updated a map slot and the old socket was purged from the map that these socket can never get reattached into a map even though their related psock has been dropped entirely at that point.
Reason is that tcp_cleanup_ulp() leaves the old icsk->icsk_ulp_ops intact, so that on the next tcp_set_ulp_id() the kernel returns an -EEXIST thinking there is still some active ULP attached.
BPF sockmap is the only one that has this issue as the other user, kTLS, only calls tcp_cleanup_ulp() from tcp_v4_destroy_sock() whereas sockmap semantics allow dropping the socket from the map with all related psock state being cleaned up.
Fixes: 1aa12bdf1bfb ("bpf: sockmap, add sock close() hook to remove socks") Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: John Fastabend john.fastabend@gmail.com Acked-by: Song Liu songliubraving@fb.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/tcp_ulp.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/net/ipv4/tcp_ulp.c +++ b/net/ipv4/tcp_ulp.c @@ -129,6 +129,8 @@ void tcp_cleanup_ulp(struct sock *sk) if (icsk->icsk_ulp_ops->release) icsk->icsk_ulp_ops->release(sk); module_put(icsk->icsk_ulp_ops->owner); + + icsk->icsk_ulp_ops = NULL; }
/* Change upper layer protocol for socket */