From bd83f0ac993bc5bee0b0f96c74d24cab142ba385 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Thu, 20 May 2021 18:09:55 +0200 Subject: conn: linux: protect read fds The -1 protection was removed and the wrong error was returned, causing us to read from a bogus fd. As well, remove the useless closures that aren't doing anything, since this is all synchronized anyway. Fixes: 10533c3 ("all: make conn.Bind.Open return a slice of receive functions") Signed-off-by: Jason A. Donenfeld --- conn/bind_linux.go | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-) diff --git a/conn/bind_linux.go b/conn/bind_linux.go index c10d8b6..7b970e6 100644 --- a/conn/bind_linux.go +++ b/conn/bind_linux.go @@ -148,12 +148,12 @@ again: var fns []ReceiveFunc if sock4 != -1 { - fns = append(fns, bind.makeReceiveIPv4(sock4)) bind.sock4 = sock4 + fns = append(fns, bind.receiveIPv4) } if sock6 != -1 { - fns = append(fns, bind.makeReceiveIPv6(sock6)) bind.sock6 = sock6 + fns = append(fns, bind.receiveIPv6) } if len(fns) == 0 { return nil, 0, syscall.EAFNOSUPPORT @@ -224,20 +224,26 @@ func (bind *LinuxSocketBind) Close() error { return err2 } -func (*LinuxSocketBind) makeReceiveIPv6(sock int) ReceiveFunc { - return func(buff []byte) (int, Endpoint, error) { - var end LinuxSocketEndpoint - n, err := receive6(sock, buff, &end) - return n, &end, err +func (bind *LinuxSocketBind) receiveIPv4(buf []byte) (int, Endpoint, error) { + bind.mu.RLock() + defer bind.mu.RUnlock() + if bind.sock4 == -1 { + return 0, nil, net.ErrClosed } + var end LinuxSocketEndpoint + n, err := receive4(bind.sock4, buf, &end) + return n, &end, err } -func (*LinuxSocketBind) makeReceiveIPv4(sock int) ReceiveFunc { - return func(buff []byte) (int, Endpoint, error) { - var end LinuxSocketEndpoint - n, err := receive4(sock, buff, &end) - return n, &end, err +func (bind *LinuxSocketBind) receiveIPv6(buf []byte) (int, Endpoint, error) { + bind.mu.RLock() + defer bind.mu.RUnlock() + if bind.sock6 == -1 { + return 0, nil, net.ErrClosed } + var end LinuxSocketEndpoint + n, err := receive6(bind.sock6, buf, &end) + return n, &end, err } func (bind *LinuxSocketBind) Send(buff []byte, end Endpoint) error { -- cgit v1.2.3