diff options
| -rw-r--r-- | pkg/tcpip/transport/udp/endpoint.go | 29 | ||||
| -rw-r--r-- | test/syscalls/linux/tuntap.cc | 20 |
2 files changed, 40 insertions, 9 deletions
diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go index 8c7895713..c5e3c73ef 100644 --- a/pkg/tcpip/transport/udp/endpoint.go +++ b/pkg/tcpip/transport/udp/endpoint.go @@ -15,6 +15,7 @@ package udp import ( + "gvisor.dev/gvisor/pkg/sleep" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/tcpip/buffer" @@ -425,24 +426,33 @@ func (e *endpoint) write(p tcpip.Payloader, opts tcpip.WriteOptions) (int64, <-c } var route *stack.Route + var resolve func(waker *sleep.Waker) (ch <-chan struct{}, err *tcpip.Error) var dstPort uint16 if to == nil { route = &e.route dstPort = e.dstPort - - if route.IsResolutionRequired() { - // Promote lock to exclusive if using a shared route, given that it may need to - // change in Route.Resolve() call below. + resolve = func(waker *sleep.Waker) (ch <-chan struct{}, err *tcpip.Error) { + // Promote lock to exclusive if using a shared route, given that it may + // need to change in Route.Resolve() call below. e.mu.RUnlock() - defer e.mu.RLock() - e.mu.Lock() - defer e.mu.Unlock() // Recheck state after lock was re-acquired. if e.state != StateConnected { - return 0, nil, tcpip.ErrInvalidEndpointState + err = tcpip.ErrInvalidEndpointState + } + if err == nil && route.IsResolutionRequired() { + ch, err = route.Resolve(waker) + } + + e.mu.Unlock() + e.mu.RLock() + + // Recheck state after lock was re-acquired. + if e.state != StateConnected { + err = tcpip.ErrInvalidEndpointState } + return } } else { // Reject destination address if it goes through a different @@ -473,10 +483,11 @@ func (e *endpoint) write(p tcpip.Payloader, opts tcpip.WriteOptions) (int64, <-c route = &r dstPort = dst.Port + resolve = route.Resolve } if route.IsResolutionRequired() { - if ch, err := route.Resolve(nil); err != nil { + if ch, err := resolve(nil); err != nil { if err == tcpip.ErrWouldBlock { return 0, ch, tcpip.ErrNoLinkAddress } diff --git a/test/syscalls/linux/tuntap.cc b/test/syscalls/linux/tuntap.cc index 6195b11e1..97d554e72 100644 --- a/test/syscalls/linux/tuntap.cc +++ b/test/syscalls/linux/tuntap.cc @@ -398,5 +398,25 @@ TEST_F(TuntapTest, SendUdpTriggersArpResolution) { } } +// Write hang bug found by syskaller: b/155928773 +// https://syzkaller.appspot.com/bug?id=065b893bd8d1d04a4e0a1d53c578537cde1efe99 +TEST_F(TuntapTest, WriteHangBug155928773) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_ADMIN))); + + FileDescriptor fd = + ASSERT_NO_ERRNO_AND_VALUE(OpenAndAttachTap(kTapName, "10.0.0.1")); + + int sock = socket(AF_INET, SOCK_DGRAM, 0); + ASSERT_THAT(sock, SyscallSucceeds()); + + struct sockaddr_in remote = {}; + remote.sin_family = AF_INET; + remote.sin_port = htons(42); + inet_pton(AF_INET, "10.0.0.1", &remote.sin_addr); + // Return values do not matter in this test. + connect(sock, reinterpret_cast<struct sockaddr*>(&remote), sizeof(remote)); + write(sock, "hello", 5); +} + } // namespace testing } // namespace gvisor |