From e2c1084cc8eb52bdfda299df2386ba974c320d54 Mon Sep 17 00:00:00 2001 From: Bhasker Hariharan Date: Thu, 20 Aug 2020 13:23:21 -0700 Subject: Skip listening TCP ports when trying to bind a free port. PiperOrigin-RevId: 327686558 --- pkg/sentry/socket/netstack/netstack.go | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) (limited to 'pkg/sentry') diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go index 0e5913b60..4d0e33696 100644 --- a/pkg/sentry/socket/netstack/netstack.go +++ b/pkg/sentry/socket/netstack/netstack.go @@ -803,7 +803,20 @@ func (s *socketOpsCommon) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error { } // Issue the bind request to the endpoint. - return syserr.TranslateNetstackError(s.Endpoint.Bind(addr)) + err := s.Endpoint.Bind(addr) + if err == tcpip.ErrNoPortAvailable { + // Bind always returns EADDRINUSE irrespective of if the specified port was + // already bound or if an ephemeral port was requested but none were + // available. + // + // tcpip.ErrNoPortAvailable is mapped to EAGAIN in syserr package because + // UDP connect returns EAGAIN on ephemeral port exhaustion. + // + // TCP connect returns EADDRNOTAVAIL on ephemeral port exhaustion. + err = tcpip.ErrPortInUse + } + + return syserr.TranslateNetstackError(err) } // Listen implements the linux syscall listen(2) for sockets backed by -- cgit v1.2.3