diff options
Diffstat (limited to 'test')
| -rw-r--r-- | test/iptables/BUILD | 1 | ||||
| -rw-r--r-- | test/iptables/iptables_test.go | 8 | ||||
| -rw-r--r-- | test/iptables/iptables_unsafe.go | 63 | ||||
| -rw-r--r-- | test/iptables/iptables_util.go | 51 | ||||
| -rw-r--r-- | test/iptables/nat.go | 152 |
5 files changed, 268 insertions, 7 deletions
diff --git a/test/iptables/BUILD b/test/iptables/BUILD index 40b63ebbe..66453772a 100644 --- a/test/iptables/BUILD +++ b/test/iptables/BUILD @@ -9,6 +9,7 @@ go_library( "filter_input.go", "filter_output.go", "iptables.go", + "iptables_unsafe.go", "iptables_util.go", "nat.go", ], diff --git a/test/iptables/iptables_test.go b/test/iptables/iptables_test.go index 550b6198a..fda5f694f 100644 --- a/test/iptables/iptables_test.go +++ b/test/iptables/iptables_test.go @@ -371,3 +371,11 @@ func TestFilterAddrs(t *testing.T) { } } } + +func TestNATPreOriginalDst(t *testing.T) { + singleTest(t, NATPreOriginalDst{}) +} + +func TestNATOutOriginalDst(t *testing.T) { + singleTest(t, NATOutOriginalDst{}) +} diff --git a/test/iptables/iptables_unsafe.go b/test/iptables/iptables_unsafe.go new file mode 100644 index 000000000..bd85a8fea --- /dev/null +++ b/test/iptables/iptables_unsafe.go @@ -0,0 +1,63 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package iptables + +import ( + "fmt" + "syscall" + "unsafe" +) + +type originalDstError struct { + errno syscall.Errno +} + +func (e originalDstError) Error() string { + return fmt.Sprintf("errno (%d) when calling getsockopt(SO_ORIGINAL_DST): %v", int(e.errno), e.errno.Error()) +} + +// SO_ORIGINAL_DST gets the original destination of a redirected packet via +// getsockopt. +const SO_ORIGINAL_DST = 80 + +func originalDestination4(connfd int) (syscall.RawSockaddrInet4, error) { + var addr syscall.RawSockaddrInet4 + var addrLen uint32 = syscall.SizeofSockaddrInet4 + if errno := originalDestination(connfd, syscall.SOL_IP, unsafe.Pointer(&addr), &addrLen); errno != 0 { + return syscall.RawSockaddrInet4{}, originalDstError{errno} + } + return addr, nil +} + +func originalDestination6(connfd int) (syscall.RawSockaddrInet6, error) { + var addr syscall.RawSockaddrInet6 + var addrLen uint32 = syscall.SizeofSockaddrInet6 + if errno := originalDestination(connfd, syscall.SOL_IPV6, unsafe.Pointer(&addr), &addrLen); errno != 0 { + return syscall.RawSockaddrInet6{}, originalDstError{errno} + } + return addr, nil +} + +func originalDestination(connfd int, level uintptr, optval unsafe.Pointer, optlen *uint32) syscall.Errno { + _, _, errno := syscall.Syscall6( + syscall.SYS_GETSOCKOPT, + uintptr(connfd), + level, + SO_ORIGINAL_DST, + uintptr(optval), + uintptr(unsafe.Pointer(optlen)), + 0) + return errno +} diff --git a/test/iptables/iptables_util.go b/test/iptables/iptables_util.go index ca80a4b5f..5125fe47b 100644 --- a/test/iptables/iptables_util.go +++ b/test/iptables/iptables_util.go @@ -15,6 +15,8 @@ package iptables import ( + "encoding/binary" + "errors" "fmt" "net" "os/exec" @@ -218,17 +220,58 @@ func filterAddrs(addrs []string, ipv6 bool) []string { // getInterfaceName returns the name of the interface other than loopback. func getInterfaceName() (string, bool) { - var ifname string + iface, ok := getNonLoopbackInterface() + if !ok { + return "", false + } + return iface.Name, true +} + +func getInterfaceAddrs(ipv6 bool) ([]net.IP, error) { + iface, ok := getNonLoopbackInterface() + if !ok { + return nil, errors.New("no non-loopback interface found") + } + addrs, err := iface.Addrs() + if err != nil { + return nil, err + } + + // Get only IPv4 or IPv6 addresses. + ips := make([]net.IP, 0, len(addrs)) + for _, addr := range addrs { + parts := strings.Split(addr.String(), "/") + var ip net.IP + // To16() returns IPv4 addresses as IPv4-mapped IPv6 addresses. + // So we check whether To4() returns nil to test whether the + // address is v4 or v6. + if v4 := net.ParseIP(parts[0]).To4(); ipv6 && v4 == nil { + ip = net.ParseIP(parts[0]).To16() + } else { + ip = v4 + } + if ip != nil { + ips = append(ips, ip) + } + } + return ips, nil +} + +func getNonLoopbackInterface() (net.Interface, bool) { if interfaces, err := net.Interfaces(); err == nil { for _, intf := range interfaces { if intf.Name != "lo" { - ifname = intf.Name - break + return intf, true } } } + return net.Interface{}, false +} - return ifname, ifname != "" +func htons(x uint16) uint16 { + buf := make([]byte, 2) + binary.BigEndian.PutUint16(buf, x) + return binary.LittleEndian.Uint16(buf) } func localIP(ipv6 bool) string { diff --git a/test/iptables/nat.go b/test/iptables/nat.go index ac0d91bb2..b7fea2527 100644 --- a/test/iptables/nat.go +++ b/test/iptables/nat.go @@ -18,12 +18,11 @@ import ( "errors" "fmt" "net" + "syscall" "time" ) -const ( - redirectPort = 42 -) +const redirectPort = 42 func init() { RegisterTestCase(NATPreRedirectUDPPort{}) @@ -42,6 +41,8 @@ func init() { RegisterTestCase(NATOutRedirectInvert{}) RegisterTestCase(NATRedirectRequiresProtocol{}) RegisterTestCase(NATLoopbackSkipsPrerouting{}) + RegisterTestCase(NATPreOriginalDst{}) + RegisterTestCase(NATOutOriginalDst{}) } // NATPreRedirectUDPPort tests that packets are redirected to different port. @@ -471,6 +472,151 @@ func (NATLoopbackSkipsPrerouting) LocalAction(ip net.IP, ipv6 bool) error { return nil } +// NATPreOriginalDst tests that SO_ORIGINAL_DST returns the pre-NAT destination +// of PREROUTING NATted packets. +type NATPreOriginalDst struct{} + +// Name implements TestCase.Name. +func (NATPreOriginalDst) Name() string { + return "NATPreOriginalDst" +} + +// ContainerAction implements TestCase.ContainerAction. +func (NATPreOriginalDst) ContainerAction(ip net.IP, ipv6 bool) error { + // Redirect incoming TCP connections to acceptPort. + if err := natTable(ipv6, "-A", "PREROUTING", + "-p", "tcp", + "--destination-port", fmt.Sprintf("%d", dropPort), + "-j", "REDIRECT", "--to-port", fmt.Sprintf("%d", acceptPort)); err != nil { + return err + } + + addrs, err := getInterfaceAddrs(ipv6) + if err != nil { + return err + } + return listenForRedirectedConn(ipv6, addrs) +} + +// LocalAction implements TestCase.LocalAction. +func (NATPreOriginalDst) LocalAction(ip net.IP, ipv6 bool) error { + return connectTCP(ip, dropPort, sendloopDuration) +} + +// NATOutOriginalDst tests that SO_ORIGINAL_DST returns the pre-NAT destination +// of OUTBOUND NATted packets. +type NATOutOriginalDst struct{} + +// Name implements TestCase.Name. +func (NATOutOriginalDst) Name() string { + return "NATOutOriginalDst" +} + +// ContainerAction implements TestCase.ContainerAction. +func (NATOutOriginalDst) ContainerAction(ip net.IP, ipv6 bool) error { + // Redirect incoming TCP connections to acceptPort. + if err := natTable(ipv6, "-A", "OUTPUT", "-p", "tcp", "-j", "REDIRECT", "--to-port", fmt.Sprintf("%d", acceptPort)); err != nil { + return err + } + + connCh := make(chan error) + go func() { + connCh <- connectTCP(ip, dropPort, sendloopDuration) + }() + + if err := listenForRedirectedConn(ipv6, []net.IP{ip}); err != nil { + return err + } + return <-connCh +} + +// LocalAction implements TestCase.LocalAction. +func (NATOutOriginalDst) LocalAction(ip net.IP, ipv6 bool) error { + // No-op. + return nil +} + +func listenForRedirectedConn(ipv6 bool, originalDsts []net.IP) error { + // The net package doesn't give guarantee access to the connection's + // underlying FD, and thus we cannot call getsockopt. We have to use + // traditional syscalls for SO_ORIGINAL_DST. + + // Create the listening socket, bind, listen, and accept. + family := syscall.AF_INET + if ipv6 { + family = syscall.AF_INET6 + } + sockfd, err := syscall.Socket(family, syscall.SOCK_STREAM, 0) + if err != nil { + return err + } + defer syscall.Close(sockfd) + + var bindAddr syscall.Sockaddr + if ipv6 { + bindAddr = &syscall.SockaddrInet6{ + Port: acceptPort, + Addr: [16]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, // in6addr_any + } + } else { + bindAddr = &syscall.SockaddrInet4{ + Port: acceptPort, + Addr: [4]byte{0, 0, 0, 0}, // INADDR_ANY + } + } + if err := syscall.Bind(sockfd, bindAddr); err != nil { + return err + } + + if err := syscall.Listen(sockfd, 1); err != nil { + return err + } + + connfd, _, err := syscall.Accept(sockfd) + if err != nil { + return err + } + defer syscall.Close(connfd) + + // Verify that, despite listening on acceptPort, SO_ORIGINAL_DST + // indicates the packet was sent to originalDst:dropPort. + if ipv6 { + got, err := originalDestination6(connfd) + if err != nil { + return err + } + // The original destination could be any of our IPs. + for _, dst := range originalDsts { + want := syscall.RawSockaddrInet6{ + Family: syscall.AF_INET6, + Port: htons(dropPort), + } + copy(want.Addr[:], dst.To16()) + if got == want { + return nil + } + } + return fmt.Errorf("SO_ORIGINAL_DST returned %+v, but wanted one of %+v (note: port numbers are in network byte order)", got, originalDsts) + } else { + got, err := originalDestination4(connfd) + if err != nil { + return err + } + // The original destination could be any of our IPs. + for _, dst := range originalDsts { + want := syscall.RawSockaddrInet4{ + Family: syscall.AF_INET, + Port: htons(dropPort), + } + copy(want.Addr[:], dst.To4()) + if got == want { + return nil + } + } + return fmt.Errorf("SO_ORIGINAL_DST returned %+v, but wanted one of %+v (note: port numbers are in network byte order)", got, originalDsts) + } +} + // loopbackTests runs an iptables rule and ensures that packets sent to // dest:dropPort are received by localhost:acceptPort. func loopbackTest(ipv6 bool, dest net.IP, args ...string) error { |