From 42fb7d349137bd8847e7c3df6493fde3bc8e6e89 Mon Sep 17 00:00:00 2001 From: Andrei Vagin Date: Mon, 2 Mar 2020 10:32:20 -0800 Subject: [PATCH] socket: take readMu to access readView DATA RACE in netstack.(*SocketOperations).fetchReadView Write at 0x00c001dca138 by goroutine 1001: gvisor.dev/gvisor/pkg/sentry/socket/netstack.(*SocketOperations).fetchReadView() pkg/sentry/socket/netstack/netstack.go:418 +0x85 gvisor.dev/gvisor/pkg/sentry/socket/netstack.(*SocketOperations).coalescingRead() pkg/sentry/socket/netstack/netstack.go:2309 +0x67 gvisor.dev/gvisor/pkg/sentry/socket/netstack.(*SocketOperations).nonBlockingRead() pkg/sentry/socket/netstack/netstack.go:2378 +0x183d Previous read at 0x00c001dca138 by goroutine 1111: gvisor.dev/gvisor/pkg/sentry/socket/netstack.(*SocketOperations).Ioctl() pkg/sentry/socket/netstack/netstack.go:2666 +0x533 gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Ioctl() Reported-by: syzbot+d4c3885fcc346f08deb6@syzkaller.appspotmail.com PiperOrigin-RevId: 298387377 --- pkg/sentry/socket/netstack/netstack.go | 2 ++ 1 file changed, 2 insertions(+) diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go index 48c268bfa..1eeb37446 100644 --- a/pkg/sentry/socket/netstack/netstack.go +++ b/pkg/sentry/socket/netstack/netstack.go @@ -2663,7 +2663,9 @@ func (s *SocketOperations) Ioctl(ctx context.Context, _ *fs.File, io usermem.IO, } // Add bytes removed from the endpoint but not yet sent to the caller. + s.readMu.Lock() v += len(s.readView) + s.readMu.Unlock() if v > math.MaxInt32 { v = math.MaxInt32