From a2c51efe3669f0380042b2375eae79e403d3680c Mon Sep 17 00:00:00 2001 From: Ian Gudger Date: Tue, 29 Oct 2019 16:13:43 -0700 Subject: Add endpoint tracking to the stack. In the future this will replace DanglingEndpoints. DanglingEndpoints must be kept for now due to issues with save/restore. This is arguably a cleaner design and allows the stack to know which transport endpoints might still be using its link endpoints. Updates #837 PiperOrigin-RevId: 277386633 --- pkg/sentry/inet/inet.go | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'pkg/sentry/inet/inet.go') diff --git a/pkg/sentry/inet/inet.go b/pkg/sentry/inet/inet.go index bc6cb1095..a7dfb78a7 100644 --- a/pkg/sentry/inet/inet.go +++ b/pkg/sentry/inet/inet.go @@ -15,6 +15,8 @@ // Package inet defines semantics for IP stacks. package inet +import "gvisor.dev/gvisor/pkg/tcpip/stack" + // Stack represents a TCP/IP stack. type Stack interface { // Interfaces returns all network interfaces as a mapping from interface @@ -58,6 +60,16 @@ type Stack interface { // Resume restarts the network stack after restore. Resume() + + // RegisteredEndpoints returns all endpoints which are currently registered. + RegisteredEndpoints() []stack.TransportEndpoint + + // CleanupEndpoints returns endpoints currently in the cleanup state. + CleanupEndpoints() []stack.TransportEndpoint + + // RestoreCleanupEndpoints adds endpoints to cleanup tracking. This is useful + // for restoring a stack after a save. + RestoreCleanupEndpoints([]stack.TransportEndpoint) } // Interface contains information about a network interface. -- cgit v1.2.3 From 665b614e4a6e715bac25bea15c5c29184016e549 Mon Sep 17 00:00:00 2001 From: Ting-Yu Wang Date: Tue, 4 Feb 2020 18:04:26 -0800 Subject: Support RTM_NEWADDR and RTM_GETLINK in (rt)netlink. PiperOrigin-RevId: 293271055 --- pkg/sentry/inet/inet.go | 4 + pkg/sentry/inet/test_stack.go | 6 + pkg/sentry/socket/hostinet/stack.go | 5 + pkg/sentry/socket/netlink/BUILD | 14 +- pkg/sentry/socket/netlink/message.go | 129 +++++++++++ pkg/sentry/socket/netlink/message_test.go | 312 +++++++++++++++++++++++++++ pkg/sentry/socket/netlink/provider.go | 2 +- pkg/sentry/socket/netlink/route/BUILD | 2 - pkg/sentry/socket/netlink/route/protocol.go | 238 ++++++++++++++------ pkg/sentry/socket/netlink/socket.go | 54 ++--- pkg/sentry/socket/netlink/uevent/protocol.go | 2 +- pkg/sentry/socket/netstack/stack.go | 55 +++++ pkg/tcpip/stack/stack.go | 9 + test/syscalls/linux/BUILD | 2 + test/syscalls/linux/socket_netlink_route.cc | 296 ++++++++++++++++++++----- test/syscalls/linux/socket_netlink_util.cc | 45 +++- test/syscalls/linux/socket_netlink_util.h | 9 + 17 files changed, 1022 insertions(+), 162 deletions(-) create mode 100644 pkg/sentry/socket/netlink/message_test.go (limited to 'pkg/sentry/inet/inet.go') diff --git a/pkg/sentry/inet/inet.go b/pkg/sentry/inet/inet.go index a7dfb78a7..2916a0644 100644 --- a/pkg/sentry/inet/inet.go +++ b/pkg/sentry/inet/inet.go @@ -28,6 +28,10 @@ type Stack interface { // interface indexes to a slice of associated interface address properties. InterfaceAddrs() map[int32][]InterfaceAddr + // AddInterfaceAddr adds an address to the network interface identified by + // index. + AddInterfaceAddr(idx int32, addr InterfaceAddr) error + // SupportsIPv6 returns true if the stack supports IPv6 connectivity. SupportsIPv6() bool diff --git a/pkg/sentry/inet/test_stack.go b/pkg/sentry/inet/test_stack.go index dcfcbd97e..d8961fc94 100644 --- a/pkg/sentry/inet/test_stack.go +++ b/pkg/sentry/inet/test_stack.go @@ -47,6 +47,12 @@ func (s *TestStack) InterfaceAddrs() map[int32][]InterfaceAddr { return s.InterfaceAddrsMap } +// AddInterfaceAddr implements Stack.AddInterfaceAddr. +func (s *TestStack) AddInterfaceAddr(idx int32, addr InterfaceAddr) error { + s.InterfaceAddrsMap[idx] = append(s.InterfaceAddrsMap[idx], addr) + return nil +} + // SupportsIPv6 implements Stack.SupportsIPv6. func (s *TestStack) SupportsIPv6() bool { return s.SupportsIPv6Flag diff --git a/pkg/sentry/socket/hostinet/stack.go b/pkg/sentry/socket/hostinet/stack.go index 034eca676..a48082631 100644 --- a/pkg/sentry/socket/hostinet/stack.go +++ b/pkg/sentry/socket/hostinet/stack.go @@ -310,6 +310,11 @@ func (s *Stack) InterfaceAddrs() map[int32][]inet.InterfaceAddr { return addrs } +// AddInterfaceAddr implements inet.Stack.AddInterfaceAddr. +func (s *Stack) AddInterfaceAddr(idx int32, addr inet.InterfaceAddr) error { + return syserror.EACCES +} + // SupportsIPv6 implements inet.Stack.SupportsIPv6. func (s *Stack) SupportsIPv6() bool { return s.supportsIPv6 diff --git a/pkg/sentry/socket/netlink/BUILD b/pkg/sentry/socket/netlink/BUILD index f8b8e467d..1911cd9b8 100644 --- a/pkg/sentry/socket/netlink/BUILD +++ b/pkg/sentry/socket/netlink/BUILD @@ -1,4 +1,4 @@ -load("//tools:defs.bzl", "go_library") +load("//tools:defs.bzl", "go_library", "go_test") package(licenses = ["notice"]) @@ -33,3 +33,15 @@ go_library( "//pkg/waiter", ], ) + +go_test( + name = "netlink_test", + size = "small", + srcs = [ + "message_test.go", + ], + deps = [ + ":netlink", + "//pkg/abi/linux", + ], +) diff --git a/pkg/sentry/socket/netlink/message.go b/pkg/sentry/socket/netlink/message.go index b21e0ca4b..4ea252ccb 100644 --- a/pkg/sentry/socket/netlink/message.go +++ b/pkg/sentry/socket/netlink/message.go @@ -30,8 +30,16 @@ func alignUp(length int, align uint) int { return (length + int(align) - 1) &^ (int(align) - 1) } +// alignPad returns the length of padding required for alignment. +// +// Preconditions: align is a power of two. +func alignPad(length int, align uint) int { + return alignUp(length, align) - length +} + // Message contains a complete serialized netlink message. type Message struct { + hdr linux.NetlinkMessageHeader buf []byte } @@ -40,10 +48,86 @@ type Message struct { // The header length will be updated by Finalize. func NewMessage(hdr linux.NetlinkMessageHeader) *Message { return &Message{ + hdr: hdr, buf: binary.Marshal(nil, usermem.ByteOrder, hdr), } } +// ParseMessage parses the first message seen at buf, returning the rest of the +// buffer. If message is malformed, ok of false is returned. For last message, +// padding check is loose, if there isn't enought padding, whole buf is consumed +// and ok is set to true. +func ParseMessage(buf []byte) (msg *Message, rest []byte, ok bool) { + b := BytesView(buf) + + hdrBytes, ok := b.Extract(linux.NetlinkMessageHeaderSize) + if !ok { + return + } + var hdr linux.NetlinkMessageHeader + binary.Unmarshal(hdrBytes, usermem.ByteOrder, &hdr) + + // Msg portion. + totalMsgLen := int(hdr.Length) + _, ok = b.Extract(totalMsgLen - linux.NetlinkMessageHeaderSize) + if !ok { + return + } + + // Padding. + numPad := alignPad(totalMsgLen, linux.NLMSG_ALIGNTO) + // Linux permits the last message not being aligned, just consume all of it. + // Ref: net/netlink/af_netlink.c:netlink_rcv_skb + if numPad > len(b) { + numPad = len(b) + } + _, ok = b.Extract(numPad) + if !ok { + return + } + + return &Message{ + hdr: hdr, + buf: buf[:totalMsgLen], + }, []byte(b), true +} + +// Header returns the header of this message. +func (m *Message) Header() linux.NetlinkMessageHeader { + return m.hdr +} + +// GetData unmarshals the payload message header from this netlink message, and +// returns the attributes portion. +func (m *Message) GetData(msg interface{}) (AttrsView, bool) { + b := BytesView(m.buf) + + _, ok := b.Extract(linux.NetlinkMessageHeaderSize) + if !ok { + return nil, false + } + + size := int(binary.Size(msg)) + msgBytes, ok := b.Extract(size) + if !ok { + return nil, false + } + binary.Unmarshal(msgBytes, usermem.ByteOrder, msg) + + numPad := alignPad(linux.NetlinkMessageHeaderSize+size, linux.NLMSG_ALIGNTO) + // Linux permits the last message not being aligned, just consume all of it. + // Ref: net/netlink/af_netlink.c:netlink_rcv_skb + if numPad > len(b) { + numPad = len(b) + } + _, ok = b.Extract(numPad) + if !ok { + return nil, false + } + + return AttrsView(b), true +} + // Finalize returns the []byte containing the entire message, with the total // length set in the message header. The Message must not be modified after // calling Finalize. @@ -157,3 +241,48 @@ func (ms *MessageSet) AddMessage(hdr linux.NetlinkMessageHeader) *Message { ms.Messages = append(ms.Messages, m) return m } + +// AttrsView is a view into the attributes portion of a netlink message. +type AttrsView []byte + +// Empty returns whether there is no attribute left in v. +func (v AttrsView) Empty() bool { + return len(v) == 0 +} + +// ParseFirst parses first netlink attribute at the beginning of v. +func (v AttrsView) ParseFirst() (hdr linux.NetlinkAttrHeader, value []byte, rest AttrsView, ok bool) { + b := BytesView(v) + + hdrBytes, ok := b.Extract(linux.NetlinkAttrHeaderSize) + if !ok { + return + } + binary.Unmarshal(hdrBytes, usermem.ByteOrder, &hdr) + + value, ok = b.Extract(int(hdr.Length) - linux.NetlinkAttrHeaderSize) + if !ok { + return + } + + _, ok = b.Extract(alignPad(int(hdr.Length), linux.NLA_ALIGNTO)) + if !ok { + return + } + + return hdr, value, AttrsView(b), ok +} + +// BytesView supports extracting data from a byte slice with bounds checking. +type BytesView []byte + +// Extract removes the first n bytes from v and returns it. If n is out of +// bounds, it returns false. +func (v *BytesView) Extract(n int) ([]byte, bool) { + if n < 0 || n > len(*v) { + return nil, false + } + extracted := (*v)[:n] + *v = (*v)[n:] + return extracted, true +} diff --git a/pkg/sentry/socket/netlink/message_test.go b/pkg/sentry/socket/netlink/message_test.go new file mode 100644 index 000000000..ef13d9386 --- /dev/null +++ b/pkg/sentry/socket/netlink/message_test.go @@ -0,0 +1,312 @@ +// 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 message_test + +import ( + "bytes" + "reflect" + "testing" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/sentry/socket/netlink" +) + +type dummyNetlinkMsg struct { + Foo uint16 +} + +func TestParseMessage(t *testing.T) { + tests := []struct { + desc string + input []byte + + header linux.NetlinkMessageHeader + dataMsg *dummyNetlinkMsg + restLen int + ok bool + }{ + { + desc: "valid", + input: []byte{ + 0x14, 0x00, 0x00, 0x00, // Length + 0x01, 0x00, // Type + 0x02, 0x00, // Flags + 0x03, 0x00, 0x00, 0x00, // Seq + 0x04, 0x00, 0x00, 0x00, // PortID + 0x30, 0x31, 0x00, 0x00, // Data message with 2 bytes padding + }, + header: linux.NetlinkMessageHeader{ + Length: 20, + Type: 1, + Flags: 2, + Seq: 3, + PortID: 4, + }, + dataMsg: &dummyNetlinkMsg{ + Foo: 0x3130, + }, + restLen: 0, + ok: true, + }, + { + desc: "valid with next message", + input: []byte{ + 0x14, 0x00, 0x00, 0x00, // Length + 0x01, 0x00, // Type + 0x02, 0x00, // Flags + 0x03, 0x00, 0x00, 0x00, // Seq + 0x04, 0x00, 0x00, 0x00, // PortID + 0x30, 0x31, 0x00, 0x00, // Data message with 2 bytes padding + 0xFF, // Next message (rest) + }, + header: linux.NetlinkMessageHeader{ + Length: 20, + Type: 1, + Flags: 2, + Seq: 3, + PortID: 4, + }, + dataMsg: &dummyNetlinkMsg{ + Foo: 0x3130, + }, + restLen: 1, + ok: true, + }, + { + desc: "valid for last message without padding", + input: []byte{ + 0x12, 0x00, 0x00, 0x00, // Length + 0x01, 0x00, // Type + 0x02, 0x00, // Flags + 0x03, 0x00, 0x00, 0x00, // Seq + 0x04, 0x00, 0x00, 0x00, // PortID + 0x30, 0x31, // Data message + }, + header: linux.NetlinkMessageHeader{ + Length: 18, + Type: 1, + Flags: 2, + Seq: 3, + PortID: 4, + }, + dataMsg: &dummyNetlinkMsg{ + Foo: 0x3130, + }, + restLen: 0, + ok: true, + }, + { + desc: "valid for last message not to be aligned", + input: []byte{ + 0x13, 0x00, 0x00, 0x00, // Length + 0x01, 0x00, // Type + 0x02, 0x00, // Flags + 0x03, 0x00, 0x00, 0x00, // Seq + 0x04, 0x00, 0x00, 0x00, // PortID + 0x30, 0x31, // Data message + 0x00, // Excessive 1 byte permitted at end + }, + header: linux.NetlinkMessageHeader{ + Length: 19, + Type: 1, + Flags: 2, + Seq: 3, + PortID: 4, + }, + dataMsg: &dummyNetlinkMsg{ + Foo: 0x3130, + }, + restLen: 0, + ok: true, + }, + { + desc: "header.Length too short", + input: []byte{ + 0x04, 0x00, 0x00, 0x00, // Length + 0x01, 0x00, // Type + 0x02, 0x00, // Flags + 0x03, 0x00, 0x00, 0x00, // Seq + 0x04, 0x00, 0x00, 0x00, // PortID + 0x30, 0x31, 0x00, 0x00, // Data message with 2 bytes padding + }, + ok: false, + }, + { + desc: "header.Length too long", + input: []byte{ + 0xFF, 0xFF, 0x00, 0x00, // Length + 0x01, 0x00, // Type + 0x02, 0x00, // Flags + 0x03, 0x00, 0x00, 0x00, // Seq + 0x04, 0x00, 0x00, 0x00, // PortID + 0x30, 0x31, 0x00, 0x00, // Data message with 2 bytes padding + }, + ok: false, + }, + { + desc: "header incomplete", + input: []byte{ + 0x04, 0x00, 0x00, 0x00, // Length + }, + ok: false, + }, + { + desc: "empty message", + input: []byte{}, + ok: false, + }, + } + for _, test := range tests { + msg, rest, ok := netlink.ParseMessage(test.input) + if ok != test.ok { + t.Errorf("%v: got ok = %v, want = %v", test.desc, ok, test.ok) + continue + } + if !test.ok { + continue + } + if !reflect.DeepEqual(msg.Header(), test.header) { + t.Errorf("%v: got hdr = %+v, want = %+v", test.desc, msg.Header(), test.header) + } + + dataMsg := &dummyNetlinkMsg{} + _, dataOk := msg.GetData(dataMsg) + if !dataOk { + t.Errorf("%v: GetData.ok = %v, want = true", test.desc, dataOk) + } else if !reflect.DeepEqual(dataMsg, test.dataMsg) { + t.Errorf("%v: GetData.msg = %+v, want = %+v", test.desc, dataMsg, test.dataMsg) + } + + if got, want := rest, test.input[len(test.input)-test.restLen:]; !bytes.Equal(got, want) { + t.Errorf("%v: got rest = %v, want = %v", test.desc, got, want) + } + } +} + +func TestAttrView(t *testing.T) { + tests := []struct { + desc string + input []byte + + // Outputs for ParseFirst. + hdr linux.NetlinkAttrHeader + value []byte + restLen int + ok bool + + // Outputs for Empty. + isEmpty bool + }{ + { + desc: "valid", + input: []byte{ + 0x06, 0x00, // Length + 0x01, 0x00, // Type + 0x30, 0x31, 0x00, 0x00, // Data with 2 bytes padding + }, + hdr: linux.NetlinkAttrHeader{ + Length: 6, + Type: 1, + }, + value: []byte{0x30, 0x31}, + restLen: 0, + ok: true, + isEmpty: false, + }, + { + desc: "at alignment", + input: []byte{ + 0x08, 0x00, // Length + 0x01, 0x00, // Type + 0x30, 0x31, 0x32, 0x33, // Data + }, + hdr: linux.NetlinkAttrHeader{ + Length: 8, + Type: 1, + }, + value: []byte{0x30, 0x31, 0x32, 0x33}, + restLen: 0, + ok: true, + isEmpty: false, + }, + { + desc: "at alignment with rest data", + input: []byte{ + 0x08, 0x00, // Length + 0x01, 0x00, // Type + 0x30, 0x31, 0x32, 0x33, // Data + 0xFF, 0xFE, // Rest data + }, + hdr: linux.NetlinkAttrHeader{ + Length: 8, + Type: 1, + }, + value: []byte{0x30, 0x31, 0x32, 0x33}, + restLen: 2, + ok: true, + isEmpty: false, + }, + { + desc: "hdr.Length too long", + input: []byte{ + 0xFF, 0x00, // Length + 0x01, 0x00, // Type + 0x30, 0x31, 0x32, 0x33, // Data + }, + ok: false, + isEmpty: false, + }, + { + desc: "hdr.Length too short", + input: []byte{ + 0x01, 0x00, // Length + 0x01, 0x00, // Type + 0x30, 0x31, 0x32, 0x33, // Data + }, + ok: false, + isEmpty: false, + }, + { + desc: "empty", + input: []byte{}, + ok: false, + isEmpty: true, + }, + } + for _, test := range tests { + attrs := netlink.AttrsView(test.input) + + // Test ParseFirst(). + hdr, value, rest, ok := attrs.ParseFirst() + if ok != test.ok { + t.Errorf("%v: got ok = %v, want = %v", test.desc, ok, test.ok) + } else if test.ok { + if !reflect.DeepEqual(hdr, test.hdr) { + t.Errorf("%v: got hdr = %+v, want = %+v", test.desc, hdr, test.hdr) + } + if !bytes.Equal(value, test.value) { + t.Errorf("%v: got value = %v, want = %v", test.desc, value, test.value) + } + if wantRest := test.input[len(test.input)-test.restLen:]; !bytes.Equal(rest, wantRest) { + t.Errorf("%v: got rest = %v, want = %v", test.desc, rest, wantRest) + } + } + + // Test Empty(). + if got, want := attrs.Empty(), test.isEmpty; got != want { + t.Errorf("%v: got empty = %v, want = %v", test.desc, got, want) + } + } +} diff --git a/pkg/sentry/socket/netlink/provider.go b/pkg/sentry/socket/netlink/provider.go index 07f860a49..b0dc70e5c 100644 --- a/pkg/sentry/socket/netlink/provider.go +++ b/pkg/sentry/socket/netlink/provider.go @@ -42,7 +42,7 @@ type Protocol interface { // If err == nil, any messages added to ms will be sent back to the // other end of the socket. Setting ms.Multi will cause an NLMSG_DONE // message to be sent even if ms contains no messages. - ProcessMessage(ctx context.Context, hdr linux.NetlinkMessageHeader, data []byte, ms *MessageSet) *syserr.Error + ProcessMessage(ctx context.Context, msg *Message, ms *MessageSet) *syserr.Error } // Provider is a function that creates a new Protocol for a specific netlink diff --git a/pkg/sentry/socket/netlink/route/BUILD b/pkg/sentry/socket/netlink/route/BUILD index 622a1eafc..93127398d 100644 --- a/pkg/sentry/socket/netlink/route/BUILD +++ b/pkg/sentry/socket/netlink/route/BUILD @@ -10,13 +10,11 @@ go_library( visibility = ["//pkg/sentry:internal"], deps = [ "//pkg/abi/linux", - "//pkg/binary", "//pkg/context", "//pkg/sentry/inet", "//pkg/sentry/kernel", "//pkg/sentry/kernel/auth", "//pkg/sentry/socket/netlink", "//pkg/syserr", - "//pkg/usermem", ], ) diff --git a/pkg/sentry/socket/netlink/route/protocol.go b/pkg/sentry/socket/netlink/route/protocol.go index 2b3c7f5b3..c84d8bd7c 100644 --- a/pkg/sentry/socket/netlink/route/protocol.go +++ b/pkg/sentry/socket/netlink/route/protocol.go @@ -17,16 +17,15 @@ package route import ( "bytes" + "syscall" "gvisor.dev/gvisor/pkg/abi/linux" - "gvisor.dev/gvisor/pkg/binary" "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/inet" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" "gvisor.dev/gvisor/pkg/sentry/socket/netlink" "gvisor.dev/gvisor/pkg/syserr" - "gvisor.dev/gvisor/pkg/usermem" ) // commandKind describes the operational class of a message type. @@ -69,13 +68,7 @@ func (p *Protocol) CanSend() bool { } // dumpLinks handles RTM_GETLINK dump requests. -func (p *Protocol) dumpLinks(ctx context.Context, hdr linux.NetlinkMessageHeader, data []byte, ms *netlink.MessageSet) *syserr.Error { - // TODO(b/68878065): Only the dump variant of the types below are - // supported. - if hdr.Flags&linux.NLM_F_DUMP != linux.NLM_F_DUMP { - return syserr.ErrNotSupported - } - +func (p *Protocol) dumpLinks(ctx context.Context, msg *netlink.Message, ms *netlink.MessageSet) *syserr.Error { // NLM_F_DUMP + RTM_GETLINK messages are supposed to include an // ifinfomsg. However, Linux <3.9 only checked for rtgenmsg, and some // userspace applications (including glibc) still include rtgenmsg. @@ -99,44 +92,105 @@ func (p *Protocol) dumpLinks(ctx context.Context, hdr linux.NetlinkMessageHeader return nil } - for id, i := range stack.Interfaces() { - m := ms.AddMessage(linux.NetlinkMessageHeader{ - Type: linux.RTM_NEWLINK, - }) + for idx, i := range stack.Interfaces() { + addNewLinkMessage(ms, idx, i) + } - m.Put(linux.InterfaceInfoMessage{ - Family: linux.AF_UNSPEC, - Type: i.DeviceType, - Index: id, - Flags: i.Flags, - }) + return nil +} - m.PutAttrString(linux.IFLA_IFNAME, i.Name) - m.PutAttr(linux.IFLA_MTU, i.MTU) +// getLinks handles RTM_GETLINK requests. +func (p *Protocol) getLink(ctx context.Context, msg *netlink.Message, ms *netlink.MessageSet) *syserr.Error { + stack := inet.StackFromContext(ctx) + if stack == nil { + // No network devices. + return nil + } - mac := make([]byte, 6) - brd := mac - if len(i.Addr) > 0 { - mac = i.Addr - brd = bytes.Repeat([]byte{0xff}, len(i.Addr)) + // Parse message. + var ifi linux.InterfaceInfoMessage + attrs, ok := msg.GetData(&ifi) + if !ok { + return syserr.ErrInvalidArgument + } + + // Parse attributes. + var byName []byte + for !attrs.Empty() { + ahdr, value, rest, ok := attrs.ParseFirst() + if !ok { + return syserr.ErrInvalidArgument } - m.PutAttr(linux.IFLA_ADDRESS, mac) - m.PutAttr(linux.IFLA_BROADCAST, brd) + attrs = rest - // TODO(gvisor.dev/issue/578): There are many more attributes. + switch ahdr.Type { + case linux.IFLA_IFNAME: + if len(value) < 1 { + return syserr.ErrInvalidArgument + } + byName = value[:len(value)-1] + + // TODO(gvisor.dev/issue/578): Support IFLA_EXT_MASK. + } } + found := false + for idx, i := range stack.Interfaces() { + switch { + case ifi.Index > 0: + if idx != ifi.Index { + continue + } + case byName != nil: + if string(byName) != i.Name { + continue + } + default: + // Criteria not specified. + return syserr.ErrInvalidArgument + } + + addNewLinkMessage(ms, idx, i) + found = true + break + } + if !found { + return syserr.ErrNoDevice + } return nil } -// dumpAddrs handles RTM_GETADDR dump requests. -func (p *Protocol) dumpAddrs(ctx context.Context, hdr linux.NetlinkMessageHeader, data []byte, ms *netlink.MessageSet) *syserr.Error { - // TODO(b/68878065): Only the dump variant of the types below are - // supported. - if hdr.Flags&linux.NLM_F_DUMP != linux.NLM_F_DUMP { - return syserr.ErrNotSupported +// addNewLinkMessage appends RTM_NEWLINK message for the given interface into +// the message set. +func addNewLinkMessage(ms *netlink.MessageSet, idx int32, i inet.Interface) { + m := ms.AddMessage(linux.NetlinkMessageHeader{ + Type: linux.RTM_NEWLINK, + }) + + m.Put(linux.InterfaceInfoMessage{ + Family: linux.AF_UNSPEC, + Type: i.DeviceType, + Index: idx, + Flags: i.Flags, + }) + + m.PutAttrString(linux.IFLA_IFNAME, i.Name) + m.PutAttr(linux.IFLA_MTU, i.MTU) + + mac := make([]byte, 6) + brd := mac + if len(i.Addr) > 0 { + mac = i.Addr + brd = bytes.Repeat([]byte{0xff}, len(i.Addr)) } + m.PutAttr(linux.IFLA_ADDRESS, mac) + m.PutAttr(linux.IFLA_BROADCAST, brd) + + // TODO(gvisor.dev/issue/578): There are many more attributes. +} +// dumpAddrs handles RTM_GETADDR dump requests. +func (p *Protocol) dumpAddrs(ctx context.Context, msg *netlink.Message, ms *netlink.MessageSet) *syserr.Error { // RTM_GETADDR dump requests need not contain anything more than the // netlink header and 1 byte protocol family common to all // NETLINK_ROUTE requests. @@ -168,6 +222,7 @@ func (p *Protocol) dumpAddrs(ctx context.Context, hdr linux.NetlinkMessageHeader Index: uint32(id), }) + m.PutAttr(linux.IFA_LOCAL, []byte(a.Addr)) m.PutAttr(linux.IFA_ADDRESS, []byte(a.Addr)) // TODO(gvisor.dev/issue/578): There are many more attributes. @@ -252,12 +307,12 @@ func fillRoute(routes []inet.Route, addr []byte) (inet.Route, *syserr.Error) { } // parseForDestination parses a message as format of RouteMessage-RtAttr-dst. -func parseForDestination(data []byte) ([]byte, *syserr.Error) { +func parseForDestination(msg *netlink.Message) ([]byte, *syserr.Error) { var rtMsg linux.RouteMessage - if len(data) < linux.SizeOfRouteMessage { + attrs, ok := msg.GetData(&rtMsg) + if !ok { return nil, syserr.ErrInvalidArgument } - binary.Unmarshal(data[:linux.SizeOfRouteMessage], usermem.ByteOrder, &rtMsg) // iproute2 added the RTM_F_LOOKUP_TABLE flag in version v4.4.0. See // commit bc234301af12. Note we don't check this flag for backward // compatibility. @@ -265,26 +320,15 @@ func parseForDestination(data []byte) ([]byte, *syserr.Error) { return nil, syserr.ErrNotSupported } - data = data[linux.SizeOfRouteMessage:] - - // TODO(gvisor.dev/issue/1611): Add generic attribute parsing. - var rtAttr linux.RtAttr - if len(data) < linux.SizeOfRtAttr { - return nil, syserr.ErrInvalidArgument + // Expect first attribute is RTA_DST. + if hdr, value, _, ok := attrs.ParseFirst(); ok && hdr.Type == linux.RTA_DST { + return value, nil } - binary.Unmarshal(data[:linux.SizeOfRtAttr], usermem.ByteOrder, &rtAttr) - if rtAttr.Type != linux.RTA_DST { - return nil, syserr.ErrInvalidArgument - } - - if len(data) < int(rtAttr.Len) { - return nil, syserr.ErrInvalidArgument - } - return data[linux.SizeOfRtAttr:rtAttr.Len], nil + return nil, syserr.ErrInvalidArgument } // dumpRoutes handles RTM_GETROUTE requests. -func (p *Protocol) dumpRoutes(ctx context.Context, hdr linux.NetlinkMessageHeader, data []byte, ms *netlink.MessageSet) *syserr.Error { +func (p *Protocol) dumpRoutes(ctx context.Context, msg *netlink.Message, ms *netlink.MessageSet) *syserr.Error { // RTM_GETROUTE dump requests need not contain anything more than the // netlink header and 1 byte protocol family common to all // NETLINK_ROUTE requests. @@ -295,10 +339,11 @@ func (p *Protocol) dumpRoutes(ctx context.Context, hdr linux.NetlinkMessageHeade return nil } + hdr := msg.Header() routeTables := stack.RouteTable() if hdr.Flags == linux.NLM_F_REQUEST { - dst, err := parseForDestination(data) + dst, err := parseForDestination(msg) if err != nil { return err } @@ -357,10 +402,55 @@ func (p *Protocol) dumpRoutes(ctx context.Context, hdr linux.NetlinkMessageHeade return nil } +// newAddr handles RTM_NEWADDR requests. +func (p *Protocol) newAddr(ctx context.Context, msg *netlink.Message, ms *netlink.MessageSet) *syserr.Error { + stack := inet.StackFromContext(ctx) + if stack == nil { + // No network stack. + return syserr.ErrProtocolNotSupported + } + + var ifa linux.InterfaceAddrMessage + attrs, ok := msg.GetData(&ifa) + if !ok { + return syserr.ErrInvalidArgument + } + + for !attrs.Empty() { + ahdr, value, rest, ok := attrs.ParseFirst() + if !ok { + return syserr.ErrInvalidArgument + } + attrs = rest + + switch ahdr.Type { + case linux.IFA_LOCAL: + err := stack.AddInterfaceAddr(int32(ifa.Index), inet.InterfaceAddr{ + Family: ifa.Family, + PrefixLen: ifa.PrefixLen, + Flags: ifa.Flags, + Addr: value, + }) + if err == syscall.EEXIST { + flags := msg.Header().Flags + if flags&linux.NLM_F_EXCL != 0 { + return syserr.ErrExists + } + } else if err != nil { + return syserr.ErrInvalidArgument + } + } + } + return nil +} + // ProcessMessage implements netlink.Protocol.ProcessMessage. -func (p *Protocol) ProcessMessage(ctx context.Context, hdr linux.NetlinkMessageHeader, data []byte, ms *netlink.MessageSet) *syserr.Error { +func (p *Protocol) ProcessMessage(ctx context.Context, msg *netlink.Message, ms *netlink.MessageSet) *syserr.Error { + hdr := msg.Header() + // All messages start with a 1 byte protocol family. - if len(data) < 1 { + var family uint8 + if _, ok := msg.GetData(&family); !ok { // Linux ignores messages missing the protocol family. See // net/core/rtnetlink.c:rtnetlink_rcv_msg. return nil @@ -374,16 +464,32 @@ func (p *Protocol) ProcessMessage(ctx context.Context, hdr linux.NetlinkMessageH } } - switch hdr.Type { - case linux.RTM_GETLINK: - return p.dumpLinks(ctx, hdr, data, ms) - case linux.RTM_GETADDR: - return p.dumpAddrs(ctx, hdr, data, ms) - case linux.RTM_GETROUTE: - return p.dumpRoutes(ctx, hdr, data, ms) - default: - return syserr.ErrNotSupported + if hdr.Flags&linux.NLM_F_DUMP == linux.NLM_F_DUMP { + // TODO(b/68878065): Only the dump variant of the types below are + // supported. + switch hdr.Type { + case linux.RTM_GETLINK: + return p.dumpLinks(ctx, msg, ms) + case linux.RTM_GETADDR: + return p.dumpAddrs(ctx, msg, ms) + case linux.RTM_GETROUTE: + return p.dumpRoutes(ctx, msg, ms) + default: + return syserr.ErrNotSupported + } + } else if hdr.Flags&linux.NLM_F_REQUEST == linux.NLM_F_REQUEST { + switch hdr.Type { + case linux.RTM_GETLINK: + return p.getLink(ctx, msg, ms) + case linux.RTM_GETROUTE: + return p.dumpRoutes(ctx, msg, ms) + case linux.RTM_NEWADDR: + return p.newAddr(ctx, msg, ms) + default: + return syserr.ErrNotSupported + } } + return syserr.ErrNotSupported } // init registers the NETLINK_ROUTE provider. diff --git a/pkg/sentry/socket/netlink/socket.go b/pkg/sentry/socket/netlink/socket.go index c4b95debb..2ca02567d 100644 --- a/pkg/sentry/socket/netlink/socket.go +++ b/pkg/sentry/socket/netlink/socket.go @@ -644,47 +644,38 @@ func (s *Socket) sendResponse(ctx context.Context, ms *MessageSet) *syserr.Error return nil } -func (s *Socket) dumpErrorMesage(ctx context.Context, hdr linux.NetlinkMessageHeader, ms *MessageSet, err *syserr.Error) *syserr.Error { +func dumpErrorMesage(hdr linux.NetlinkMessageHeader, ms *MessageSet, err *syserr.Error) { m := ms.AddMessage(linux.NetlinkMessageHeader{ Type: linux.NLMSG_ERROR, }) - m.Put(linux.NetlinkErrorMessage{ Error: int32(-err.ToLinux().Number()), Header: hdr, }) - return nil +} +func dumpAckMesage(hdr linux.NetlinkMessageHeader, ms *MessageSet) { + m := ms.AddMessage(linux.NetlinkMessageHeader{ + Type: linux.NLMSG_ERROR, + }) + m.Put(linux.NetlinkErrorMessage{ + Error: 0, + Header: hdr, + }) } // processMessages handles each message in buf, passing it to the protocol // handler for final handling. func (s *Socket) processMessages(ctx context.Context, buf []byte) *syserr.Error { for len(buf) > 0 { - if len(buf) < linux.NetlinkMessageHeaderSize { + msg, rest, ok := ParseMessage(buf) + if !ok { // Linux ignores messages that are too short. See // net/netlink/af_netlink.c:netlink_rcv_skb. break } - - var hdr linux.NetlinkMessageHeader - binary.Unmarshal(buf[:linux.NetlinkMessageHeaderSize], usermem.ByteOrder, &hdr) - - if hdr.Length < linux.NetlinkMessageHeaderSize || uint64(hdr.Length) > uint64(len(buf)) { - // Linux ignores malformed messages. See - // net/netlink/af_netlink.c:netlink_rcv_skb. - break - } - - // Data from this message. - data := buf[linux.NetlinkMessageHeaderSize:hdr.Length] - - // Advance to the next message. - next := alignUp(int(hdr.Length), linux.NLMSG_ALIGNTO) - if next >= len(buf)-1 { - next = len(buf) - 1 - } - buf = buf[next:] + buf = rest + hdr := msg.Header() // Ignore control messages. if hdr.Type < linux.NLMSG_MIN_TYPE { @@ -692,19 +683,10 @@ func (s *Socket) processMessages(ctx context.Context, buf []byte) *syserr.Error } ms := NewMessageSet(s.portID, hdr.Seq) - var err *syserr.Error - // TODO(b/68877377): ACKs not supported yet. - if hdr.Flags&linux.NLM_F_ACK == linux.NLM_F_ACK { - err = syserr.ErrNotSupported - } else { - - err = s.protocol.ProcessMessage(ctx, hdr, data, ms) - } - if err != nil { - ms = NewMessageSet(s.portID, hdr.Seq) - if err := s.dumpErrorMesage(ctx, hdr, ms, err); err != nil { - return err - } + if err := s.protocol.ProcessMessage(ctx, msg, ms); err != nil { + dumpErrorMesage(hdr, ms, err) + } else if hdr.Flags&linux.NLM_F_ACK == linux.NLM_F_ACK { + dumpAckMesage(hdr, ms) } if err := s.sendResponse(ctx, ms); err != nil { diff --git a/pkg/sentry/socket/netlink/uevent/protocol.go b/pkg/sentry/socket/netlink/uevent/protocol.go index 1ee4296bc..029ba21b5 100644 --- a/pkg/sentry/socket/netlink/uevent/protocol.go +++ b/pkg/sentry/socket/netlink/uevent/protocol.go @@ -49,7 +49,7 @@ func (p *Protocol) CanSend() bool { } // ProcessMessage implements netlink.Protocol.ProcessMessage. -func (p *Protocol) ProcessMessage(ctx context.Context, hdr linux.NetlinkMessageHeader, data []byte, ms *netlink.MessageSet) *syserr.Error { +func (p *Protocol) ProcessMessage(ctx context.Context, msg *netlink.Message, ms *netlink.MessageSet) *syserr.Error { // Silently ignore all messages. return nil } diff --git a/pkg/sentry/socket/netstack/stack.go b/pkg/sentry/socket/netstack/stack.go index 31ea66eca..0692482e9 100644 --- a/pkg/sentry/socket/netstack/stack.go +++ b/pkg/sentry/socket/netstack/stack.go @@ -20,6 +20,8 @@ import ( "gvisor.dev/gvisor/pkg/sentry/inet" "gvisor.dev/gvisor/pkg/sentry/socket/netfilter" "gvisor.dev/gvisor/pkg/syserr" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/tcpip/header" "gvisor.dev/gvisor/pkg/tcpip/iptables" "gvisor.dev/gvisor/pkg/tcpip/network/ipv4" @@ -88,6 +90,59 @@ func (s *Stack) InterfaceAddrs() map[int32][]inet.InterfaceAddr { return nicAddrs } +// AddInterfaceAddr implements inet.Stack.AddInterfaceAddr. +func (s *Stack) AddInterfaceAddr(idx int32, addr inet.InterfaceAddr) error { + var ( + protocol tcpip.NetworkProtocolNumber + address tcpip.Address + ) + switch addr.Family { + case linux.AF_INET: + if len(addr.Addr) < header.IPv4AddressSize { + return syserror.EINVAL + } + if addr.PrefixLen > header.IPv4AddressSize*8 { + return syserror.EINVAL + } + protocol = ipv4.ProtocolNumber + address = tcpip.Address(addr.Addr[:header.IPv4AddressSize]) + + case linux.AF_INET6: + if len(addr.Addr) < header.IPv6AddressSize { + return syserror.EINVAL + } + if addr.PrefixLen > header.IPv6AddressSize*8 { + return syserror.EINVAL + } + protocol = ipv6.ProtocolNumber + address = tcpip.Address(addr.Addr[:header.IPv6AddressSize]) + + default: + return syserror.ENOTSUP + } + + protocolAddress := tcpip.ProtocolAddress{ + Protocol: protocol, + AddressWithPrefix: tcpip.AddressWithPrefix{ + Address: address, + PrefixLen: int(addr.PrefixLen), + }, + } + + // Attach address to interface. + if err := s.Stack.AddProtocolAddressWithOptions(tcpip.NICID(idx), protocolAddress, stack.CanBePrimaryEndpoint); err != nil { + return syserr.TranslateNetstackError(err).ToError() + } + + // Add route for local network. + s.Stack.AddRoute(tcpip.Route{ + Destination: protocolAddress.AddressWithPrefix.Subnet(), + Gateway: "", // No gateway for local network. + NIC: tcpip.NICID(idx), + }) + return nil +} + // TCPReceiveBufferSize implements inet.Stack.TCPReceiveBufferSize. func (s *Stack) TCPReceiveBufferSize() (inet.TCPBufferSize, error) { var rs tcp.ReceiveBufferSizeOption diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go index 7057b110e..b793f1d74 100644 --- a/pkg/tcpip/stack/stack.go +++ b/pkg/tcpip/stack/stack.go @@ -795,6 +795,8 @@ func (s *Stack) Forwarding() bool { // SetRouteTable assigns the route table to be used by this stack. It // specifies which NIC to use for given destination address ranges. +// +// This method takes ownership of the table. func (s *Stack) SetRouteTable(table []tcpip.Route) { s.mu.Lock() defer s.mu.Unlock() @@ -809,6 +811,13 @@ func (s *Stack) GetRouteTable() []tcpip.Route { return append([]tcpip.Route(nil), s.routeTable...) } +// AddRoute appends a route to the route table. +func (s *Stack) AddRoute(route tcpip.Route) { + s.mu.Lock() + defer s.mu.Unlock() + s.routeTable = append(s.routeTable, route) +} + // NewEndpoint creates a new transport layer endpoint of the given protocol. func (s *Stack) NewEndpoint(transport tcpip.TransportProtocolNumber, network tcpip.NetworkProtocolNumber, waiterQueue *waiter.Queue) (tcpip.Endpoint, *tcpip.Error) { t, ok := s.transportProtocols[transport] diff --git a/test/syscalls/linux/BUILD b/test/syscalls/linux/BUILD index 273b014d6..f2e3c7072 100644 --- a/test/syscalls/linux/BUILD +++ b/test/syscalls/linux/BUILD @@ -2769,9 +2769,11 @@ cc_binary( deps = [ ":socket_netlink_util", ":socket_test_util", + "//test/util:capability_util", "//test/util:cleanup", "//test/util:file_descriptor", "@com_google_absl//absl/strings:str_format", + "@com_google_absl//absl/types:optional", gtest, "//test/util:test_main", "//test/util:test_util", diff --git a/test/syscalls/linux/socket_netlink_route.cc b/test/syscalls/linux/socket_netlink_route.cc index 1e28e658d..e5aed1eec 100644 --- a/test/syscalls/linux/socket_netlink_route.cc +++ b/test/syscalls/linux/socket_netlink_route.cc @@ -14,6 +14,7 @@ #include #include +#include #include #include #include @@ -25,8 +26,10 @@ #include "gtest/gtest.h" #include "absl/strings/str_format.h" +#include "absl/types/optional.h" #include "test/syscalls/linux/socket_netlink_util.h" #include "test/syscalls/linux/socket_test_util.h" +#include "test/util/capability_util.h" #include "test/util/cleanup.h" #include "test/util/file_descriptor.h" #include "test/util/test_util.h" @@ -38,6 +41,8 @@ namespace testing { namespace { +constexpr uint32_t kSeq = 12345; + using ::testing::AnyOf; using ::testing::Eq; @@ -113,58 +118,224 @@ void CheckGetLinkResponse(const struct nlmsghdr* hdr, int seq, int port) { // TODO(mpratt): Check ifinfomsg contents and following attrs. } +PosixError DumpLinks( + const FileDescriptor& fd, uint32_t seq, + const std::function& fn) { + struct request { + struct nlmsghdr hdr; + struct ifinfomsg ifm; + }; + + struct request req = {}; + req.hdr.nlmsg_len = sizeof(req); + req.hdr.nlmsg_type = RTM_GETLINK; + req.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP; + req.hdr.nlmsg_seq = seq; + req.ifm.ifi_family = AF_UNSPEC; + + return NetlinkRequestResponse(fd, &req, sizeof(req), fn, false); +} + TEST(NetlinkRouteTest, GetLinkDump) { FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(NetlinkBoundSocket(NETLINK_ROUTE)); uint32_t port = ASSERT_NO_ERRNO_AND_VALUE(NetlinkPortID(fd.get())); + // Loopback is common among all tests, check that it's found. + bool loopbackFound = false; + ASSERT_NO_ERRNO(DumpLinks(fd, kSeq, [&](const struct nlmsghdr* hdr) { + CheckGetLinkResponse(hdr, kSeq, port); + if (hdr->nlmsg_type != RTM_NEWLINK) { + return; + } + ASSERT_GE(hdr->nlmsg_len, NLMSG_SPACE(sizeof(struct ifinfomsg))); + const struct ifinfomsg* msg = + reinterpret_cast(NLMSG_DATA(hdr)); + std::cout << "Found interface idx=" << msg->ifi_index + << ", type=" << std::hex << msg->ifi_type; + if (msg->ifi_type == ARPHRD_LOOPBACK) { + loopbackFound = true; + EXPECT_NE(msg->ifi_flags & IFF_LOOPBACK, 0); + } + })); + EXPECT_TRUE(loopbackFound); +} + +struct Link { + int index; + std::string name; +}; + +PosixErrorOr> FindLoopbackLink() { + ASSIGN_OR_RETURN_ERRNO(FileDescriptor fd, NetlinkBoundSocket(NETLINK_ROUTE)); + + absl::optional link; + RETURN_IF_ERRNO(DumpLinks(fd, kSeq, [&](const struct nlmsghdr* hdr) { + if (hdr->nlmsg_type != RTM_NEWLINK || + hdr->nlmsg_len < NLMSG_SPACE(sizeof(struct ifinfomsg))) { + return; + } + const struct ifinfomsg* msg = + reinterpret_cast(NLMSG_DATA(hdr)); + if (msg->ifi_type == ARPHRD_LOOPBACK) { + const auto* rta = FindRtAttr(hdr, msg, IFLA_IFNAME); + if (rta == nullptr) { + // Ignore links that do not have a name. + return; + } + + link = Link(); + link->index = msg->ifi_index; + link->name = std::string(reinterpret_cast(RTA_DATA(rta))); + } + })); + return link; +} + +// CheckLinkMsg checks a netlink message against an expected link. +void CheckLinkMsg(const struct nlmsghdr* hdr, const Link& link) { + ASSERT_THAT(hdr->nlmsg_type, Eq(RTM_NEWLINK)); + ASSERT_GE(hdr->nlmsg_len, NLMSG_SPACE(sizeof(struct ifinfomsg))); + const struct ifinfomsg* msg = + reinterpret_cast(NLMSG_DATA(hdr)); + EXPECT_EQ(msg->ifi_index, link.index); + + const struct rtattr* rta = FindRtAttr(hdr, msg, IFLA_IFNAME); + EXPECT_NE(nullptr, rta) << "IFLA_IFNAME not found in message."; + if (rta != nullptr) { + std::string name(reinterpret_cast(RTA_DATA(rta))); + EXPECT_EQ(name, link.name); + } +} + +TEST(NetlinkRouteTest, GetLinkByIndex) { + absl::optional loopback_link = + ASSERT_NO_ERRNO_AND_VALUE(FindLoopbackLink()); + ASSERT_TRUE(loopback_link.has_value()); + + FileDescriptor fd = + ASSERT_NO_ERRNO_AND_VALUE(NetlinkBoundSocket(NETLINK_ROUTE)); + struct request { struct nlmsghdr hdr; struct ifinfomsg ifm; }; - constexpr uint32_t kSeq = 12345; - struct request req = {}; req.hdr.nlmsg_len = sizeof(req); req.hdr.nlmsg_type = RTM_GETLINK; - req.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP; + req.hdr.nlmsg_flags = NLM_F_REQUEST; req.hdr.nlmsg_seq = kSeq; req.ifm.ifi_family = AF_UNSPEC; + req.ifm.ifi_index = loopback_link->index; - // Loopback is common among all tests, check that it's found. - bool loopbackFound = false; + bool found = false; ASSERT_NO_ERRNO(NetlinkRequestResponse( fd, &req, sizeof(req), [&](const struct nlmsghdr* hdr) { - CheckGetLinkResponse(hdr, kSeq, port); - if (hdr->nlmsg_type != RTM_NEWLINK) { - return; - } - ASSERT_GE(hdr->nlmsg_len, NLMSG_SPACE(sizeof(struct ifinfomsg))); - const struct ifinfomsg* msg = - reinterpret_cast(NLMSG_DATA(hdr)); - std::cout << "Found interface idx=" << msg->ifi_index - << ", type=" << std::hex << msg->ifi_type; - if (msg->ifi_type == ARPHRD_LOOPBACK) { - loopbackFound = true; - EXPECT_NE(msg->ifi_flags & IFF_LOOPBACK, 0); - } + CheckLinkMsg(hdr, *loopback_link); + found = true; }, false)); - EXPECT_TRUE(loopbackFound); + EXPECT_TRUE(found) << "Netlink response does not contain any links."; } -TEST(NetlinkRouteTest, MsgHdrMsgUnsuppType) { +TEST(NetlinkRouteTest, GetLinkByName) { + absl::optional loopback_link = + ASSERT_NO_ERRNO_AND_VALUE(FindLoopbackLink()); + ASSERT_TRUE(loopback_link.has_value()); + FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(NetlinkBoundSocket(NETLINK_ROUTE)); struct request { struct nlmsghdr hdr; struct ifinfomsg ifm; + struct rtattr rtattr; + char ifname[IFNAMSIZ]; + char pad[NLMSG_ALIGNTO + RTA_ALIGNTO]; }; - constexpr uint32_t kSeq = 12345; + struct request req = {}; + req.hdr.nlmsg_type = RTM_GETLINK; + req.hdr.nlmsg_flags = NLM_F_REQUEST; + req.hdr.nlmsg_seq = kSeq; + req.ifm.ifi_family = AF_UNSPEC; + req.rtattr.rta_type = IFLA_IFNAME; + req.rtattr.rta_len = RTA_LENGTH(loopback_link->name.size() + 1); + strncpy(req.ifname, loopback_link->name.c_str(), sizeof(req.ifname)); + req.hdr.nlmsg_len = + NLMSG_LENGTH(sizeof(req.ifm)) + NLMSG_ALIGN(req.rtattr.rta_len); + + bool found = false; + ASSERT_NO_ERRNO(NetlinkRequestResponse( + fd, &req, sizeof(req), + [&](const struct nlmsghdr* hdr) { + CheckLinkMsg(hdr, *loopback_link); + found = true; + }, + false)); + EXPECT_TRUE(found) << "Netlink response does not contain any links."; +} + +TEST(NetlinkRouteTest, GetLinkByIndexNotFound) { + FileDescriptor fd = + ASSERT_NO_ERRNO_AND_VALUE(NetlinkBoundSocket(NETLINK_ROUTE)); + + struct request { + struct nlmsghdr hdr; + struct ifinfomsg ifm; + }; + + struct request req = {}; + req.hdr.nlmsg_len = sizeof(req); + req.hdr.nlmsg_type = RTM_GETLINK; + req.hdr.nlmsg_flags = NLM_F_REQUEST; + req.hdr.nlmsg_seq = kSeq; + req.ifm.ifi_family = AF_UNSPEC; + req.ifm.ifi_index = 1234590; + + EXPECT_THAT(NetlinkRequestAckOrError(fd, kSeq, &req, sizeof(req)), + PosixErrorIs(ENODEV, ::testing::_)); +} + +TEST(NetlinkRouteTest, GetLinkByNameNotFound) { + const std::string name = "nodevice?!"; + + FileDescriptor fd = + ASSERT_NO_ERRNO_AND_VALUE(NetlinkBoundSocket(NETLINK_ROUTE)); + + struct request { + struct nlmsghdr hdr; + struct ifinfomsg ifm; + struct rtattr rtattr; + char ifname[IFNAMSIZ]; + char pad[NLMSG_ALIGNTO + RTA_ALIGNTO]; + }; + + struct request req = {}; + req.hdr.nlmsg_type = RTM_GETLINK; + req.hdr.nlmsg_flags = NLM_F_REQUEST; + req.hdr.nlmsg_seq = kSeq; + req.ifm.ifi_family = AF_UNSPEC; + req.rtattr.rta_type = IFLA_IFNAME; + req.rtattr.rta_len = RTA_LENGTH(name.size() + 1); + strncpy(req.ifname, name.c_str(), sizeof(req.ifname)); + req.hdr.nlmsg_len = + NLMSG_LENGTH(sizeof(req.ifm)) + NLMSG_ALIGN(req.rtattr.rta_len); + + EXPECT_THAT(NetlinkRequestAckOrError(fd, kSeq, &req, sizeof(req)), + PosixErrorIs(ENODEV, ::testing::_)); +} + +TEST(NetlinkRouteTest, MsgHdrMsgUnsuppType) { + FileDescriptor fd = + ASSERT_NO_ERRNO_AND_VALUE(NetlinkBoundSocket(NETLINK_ROUTE)); + + struct request { + struct nlmsghdr hdr; + struct ifinfomsg ifm; + }; struct request req = {}; req.hdr.nlmsg_len = sizeof(req); @@ -175,18 +346,8 @@ TEST(NetlinkRouteTest, MsgHdrMsgUnsuppType) { req.hdr.nlmsg_seq = kSeq; req.ifm.ifi_family = AF_UNSPEC; - ASSERT_NO_ERRNO(NetlinkRequestResponse( - fd, &req, sizeof(req), - [&](const struct nlmsghdr* hdr) { - EXPECT_THAT(hdr->nlmsg_type, Eq(NLMSG_ERROR)); - EXPECT_EQ(hdr->nlmsg_seq, kSeq); - EXPECT_GE(hdr->nlmsg_len, sizeof(*hdr) + sizeof(struct nlmsgerr)); - - const struct nlmsgerr* msg = - reinterpret_cast(NLMSG_DATA(hdr)); - EXPECT_EQ(msg->error, -EOPNOTSUPP); - }, - true)); + EXPECT_THAT(NetlinkRequestAckOrError(fd, kSeq, &req, sizeof(req)), + PosixErrorIs(EOPNOTSUPP, ::testing::_)); } TEST(NetlinkRouteTest, MsgHdrMsgTrunc) { @@ -198,8 +359,6 @@ TEST(NetlinkRouteTest, MsgHdrMsgTrunc) { struct ifinfomsg ifm; }; - constexpr uint32_t kSeq = 12345; - struct request req = {}; req.hdr.nlmsg_len = sizeof(req); req.hdr.nlmsg_type = RTM_GETLINK; @@ -238,8 +397,6 @@ TEST(NetlinkRouteTest, MsgTruncMsgHdrMsgTrunc) { struct ifinfomsg ifm; }; - constexpr uint32_t kSeq = 12345; - struct request req = {}; req.hdr.nlmsg_len = sizeof(req); req.hdr.nlmsg_type = RTM_GETLINK; @@ -282,8 +439,6 @@ TEST(NetlinkRouteTest, ControlMessageIgnored) { struct ifinfomsg ifm; }; - constexpr uint32_t kSeq = 12345; - struct request req = {}; // This control message is ignored. We still receive a response for the @@ -317,8 +472,6 @@ TEST(NetlinkRouteTest, GetAddrDump) { struct rtgenmsg rgm; }; - constexpr uint32_t kSeq = 12345; - struct request req; req.hdr.nlmsg_len = sizeof(req); req.hdr.nlmsg_type = RTM_GETADDR; @@ -367,6 +520,57 @@ TEST(NetlinkRouteTest, LookupAll) { ASSERT_GT(count, 0); } +TEST(NetlinkRouteTest, AddAddr) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_ADMIN))); + + absl::optional loopback_link = + ASSERT_NO_ERRNO_AND_VALUE(FindLoopbackLink()); + ASSERT_TRUE(loopback_link.has_value()); + + FileDescriptor fd = + ASSERT_NO_ERRNO_AND_VALUE(NetlinkBoundSocket(NETLINK_ROUTE)); + + struct request { + struct nlmsghdr hdr; + struct ifaddrmsg ifa; + struct rtattr rtattr; + struct in_addr addr; + char pad[NLMSG_ALIGNTO + RTA_ALIGNTO]; + }; + + struct request req = {}; + req.hdr.nlmsg_type = RTM_NEWADDR; + req.hdr.nlmsg_seq = kSeq; + req.ifa.ifa_family = AF_INET; + req.ifa.ifa_prefixlen = 24; + req.ifa.ifa_flags = 0; + req.ifa.ifa_scope = 0; + req.ifa.ifa_index = loopback_link->index; + req.rtattr.rta_type = IFA_LOCAL; + req.rtattr.rta_len = RTA_LENGTH(sizeof(req.addr)); + inet_pton(AF_INET, "10.0.0.1", &req.addr); + req.hdr.nlmsg_len = + NLMSG_LENGTH(sizeof(req.ifa)) + NLMSG_ALIGN(req.rtattr.rta_len); + + // Create should succeed, as no such address in kernel. + req.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_ACK; + EXPECT_NO_ERRNO( + NetlinkRequestAckOrError(fd, req.hdr.nlmsg_seq, &req, req.hdr.nlmsg_len)); + + // Replace an existing address should succeed. + req.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_REPLACE | NLM_F_ACK; + req.hdr.nlmsg_seq++; + EXPECT_NO_ERRNO( + NetlinkRequestAckOrError(fd, req.hdr.nlmsg_seq, &req, req.hdr.nlmsg_len)); + + // Create exclusive should fail, as we created the address above. + req.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL | NLM_F_ACK; + req.hdr.nlmsg_seq++; + EXPECT_THAT( + NetlinkRequestAckOrError(fd, req.hdr.nlmsg_seq, &req, req.hdr.nlmsg_len), + PosixErrorIs(EEXIST, ::testing::_)); +} + // GetRouteDump tests a RTM_GETROUTE + NLM_F_DUMP request. TEST(NetlinkRouteTest, GetRouteDump) { FileDescriptor fd = @@ -378,8 +582,6 @@ TEST(NetlinkRouteTest, GetRouteDump) { struct rtmsg rtm; }; - constexpr uint32_t kSeq = 12345; - struct request req = {}; req.hdr.nlmsg_len = sizeof(req); req.hdr.nlmsg_type = RTM_GETROUTE; @@ -538,8 +740,6 @@ TEST(NetlinkRouteTest, RecvmsgTrunc) { struct rtgenmsg rgm; }; - constexpr uint32_t kSeq = 12345; - struct request req; req.hdr.nlmsg_len = sizeof(req); req.hdr.nlmsg_type = RTM_GETADDR; @@ -615,8 +815,6 @@ TEST(NetlinkRouteTest, RecvmsgTruncPeek) { struct rtgenmsg rgm; }; - constexpr uint32_t kSeq = 12345; - struct request req; req.hdr.nlmsg_len = sizeof(req); req.hdr.nlmsg_type = RTM_GETADDR; @@ -695,8 +893,6 @@ TEST(NetlinkRouteTest, NoPasscredNoCreds) { struct rtgenmsg rgm; }; - constexpr uint32_t kSeq = 12345; - struct request req; req.hdr.nlmsg_len = sizeof(req); req.hdr.nlmsg_type = RTM_GETADDR; @@ -743,8 +939,6 @@ TEST(NetlinkRouteTest, PasscredCreds) { struct rtgenmsg rgm; }; - constexpr uint32_t kSeq = 12345; - struct request req; req.hdr.nlmsg_len = sizeof(req); req.hdr.nlmsg_type = RTM_GETADDR; diff --git a/test/syscalls/linux/socket_netlink_util.cc b/test/syscalls/linux/socket_netlink_util.cc index cd2212a1a..952eecfe8 100644 --- a/test/syscalls/linux/socket_netlink_util.cc +++ b/test/syscalls/linux/socket_netlink_util.cc @@ -16,6 +16,7 @@ #include #include +#include #include #include @@ -71,9 +72,10 @@ PosixError NetlinkRequestResponse( iov.iov_base = buf.data(); iov.iov_len = buf.size(); - // Response is a series of NLM_F_MULTI messages, ending with a NLMSG_DONE - // message. + // If NLM_F_MULTI is set, response is a series of messages that ends with a + // NLMSG_DONE message. int type = -1; + int flags = 0; do { int len; RETURN_ERROR_IF_SYSCALL_FAIL(len = RetryEINTR(recvmsg)(fd.get(), &msg, 0)); @@ -89,6 +91,7 @@ PosixError NetlinkRequestResponse( for (struct nlmsghdr* hdr = reinterpret_cast(buf.data()); NLMSG_OK(hdr, len); hdr = NLMSG_NEXT(hdr, len)) { fn(hdr); + flags = hdr->nlmsg_flags; type = hdr->nlmsg_type; // Done should include an integer payload for dump_done_errno. // See net/netlink/af_netlink.c:netlink_dump @@ -98,11 +101,11 @@ PosixError NetlinkRequestResponse( EXPECT_GE(hdr->nlmsg_len, NLMSG_LENGTH(sizeof(int))); } } - } while (type != NLMSG_DONE && type != NLMSG_ERROR); + } while ((flags & NLM_F_MULTI) && type != NLMSG_DONE && type != NLMSG_ERROR); if (expect_nlmsgerr) { EXPECT_EQ(type, NLMSG_ERROR); - } else { + } else if (flags & NLM_F_MULTI) { EXPECT_EQ(type, NLMSG_DONE); } return NoError(); @@ -146,5 +149,39 @@ PosixError NetlinkRequestResponseSingle( return NoError(); } +PosixError NetlinkRequestAckOrError(const FileDescriptor& fd, uint32_t seq, + void* request, size_t len) { + // Dummy negative number for no error message received. + // We won't get a negative error number so there will be no confusion. + int err = -42; + RETURN_IF_ERRNO(NetlinkRequestResponse( + fd, request, len, + [&](const struct nlmsghdr* hdr) { + EXPECT_EQ(NLMSG_ERROR, hdr->nlmsg_type); + EXPECT_EQ(hdr->nlmsg_seq, seq); + EXPECT_GE(hdr->nlmsg_len, sizeof(*hdr) + sizeof(struct nlmsgerr)); + + const struct nlmsgerr* msg = + reinterpret_cast(NLMSG_DATA(hdr)); + err = -msg->error; + }, + true)); + return PosixError(err); +} + +const struct rtattr* FindRtAttr(const struct nlmsghdr* hdr, + const struct ifinfomsg* msg, int16_t attr) { + const int ifi_space = NLMSG_SPACE(sizeof(*msg)); + int attrlen = hdr->nlmsg_len - ifi_space; + const struct rtattr* rta = reinterpret_cast( + reinterpret_cast(hdr) + NLMSG_ALIGN(ifi_space)); + for (; RTA_OK(rta, attrlen); rta = RTA_NEXT(rta, attrlen)) { + if (rta->rta_type == attr) { + return rta; + } + } + return nullptr; +} + } // namespace testing } // namespace gvisor diff --git a/test/syscalls/linux/socket_netlink_util.h b/test/syscalls/linux/socket_netlink_util.h index 3678c0599..e13ead406 100644 --- a/test/syscalls/linux/socket_netlink_util.h +++ b/test/syscalls/linux/socket_netlink_util.h @@ -19,6 +19,7 @@ // socket.h has to be included before if_arp.h. #include #include +#include #include "test/util/file_descriptor.h" #include "test/util/posix_error.h" @@ -47,6 +48,14 @@ PosixError NetlinkRequestResponseSingle( const FileDescriptor& fd, void* request, size_t len, const std::function& fn); +// Send the passed request then expect and return an ack or error. +PosixError NetlinkRequestAckOrError(const FileDescriptor& fd, uint32_t seq, + void* request, size_t len); + +// Find rtnetlink attribute in message. +const struct rtattr* FindRtAttr(const struct nlmsghdr* hdr, + const struct ifinfomsg* msg, int16_t attr); + } // namespace testing } // namespace gvisor -- cgit v1.2.3 From 35312a95c4c8626365b4ece5ffb0bcab44b4bede Mon Sep 17 00:00:00 2001 From: Nayana Bidari Date: Wed, 5 Aug 2020 20:45:02 -0700 Subject: Add loss recovery option for TCP. /proc/sys/net/ipv4/tcp_recovery is used to enable RACK loss recovery in TCP. PiperOrigin-RevId: 325157807 --- pkg/sentry/fs/proc/sys_net.go | 95 +++++++++++++++++++++++++++++++++++++ pkg/sentry/fsimpl/proc/tasks_sys.go | 49 ++++++++++++++++++- pkg/sentry/inet/inet.go | 17 +++++++ pkg/sentry/inet/test_stack.go | 12 +++++ pkg/sentry/socket/hostinet/stack.go | 11 +++++ pkg/sentry/socket/netstack/stack.go | 14 ++++++ pkg/tcpip/transport/tcp/protocol.go | 33 +++++++++++++ test/syscalls/linux/proc_net.cc | 38 +++++++++++++++ 8 files changed, 268 insertions(+), 1 deletion(-) (limited to 'pkg/sentry/inet/inet.go') diff --git a/pkg/sentry/fs/proc/sys_net.go b/pkg/sentry/fs/proc/sys_net.go index 702fdd392..8615b60f0 100644 --- a/pkg/sentry/fs/proc/sys_net.go +++ b/pkg/sentry/fs/proc/sys_net.go @@ -272,6 +272,96 @@ func (f *tcpSackFile) Write(ctx context.Context, _ *fs.File, src usermem.IOSeque return n, f.tcpSack.stack.SetTCPSACKEnabled(*f.tcpSack.enabled) } +// +stateify savable +type tcpRecovery struct { + fsutil.SimpleFileInode + + stack inet.Stack `state:"wait"` + recovery inet.TCPLossRecovery +} + +func newTCPRecoveryInode(ctx context.Context, msrc *fs.MountSource, s inet.Stack) *fs.Inode { + ts := &tcpRecovery{ + SimpleFileInode: *fsutil.NewSimpleFileInode(ctx, fs.RootOwner, fs.FilePermsFromMode(0644), linux.PROC_SUPER_MAGIC), + stack: s, + } + sattr := fs.StableAttr{ + DeviceID: device.ProcDevice.DeviceID(), + InodeID: device.ProcDevice.NextIno(), + BlockSize: usermem.PageSize, + Type: fs.SpecialFile, + } + return fs.NewInode(ctx, ts, msrc, sattr) +} + +// Truncate implements fs.InodeOperations.Truncate. +func (*tcpRecovery) Truncate(context.Context, *fs.Inode, int64) error { + return nil +} + +// GetFile implements fs.InodeOperations.GetFile. +func (r *tcpRecovery) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags) (*fs.File, error) { + flags.Pread = true + flags.Pwrite = true + return fs.NewFile(ctx, dirent, flags, &tcpRecoveryFile{ + tcpRecovery: r, + stack: r.stack, + }), nil +} + +// +stateify savable +type tcpRecoveryFile struct { + fsutil.FileGenericSeek `state:"nosave"` + fsutil.FileNoIoctl `state:"nosave"` + fsutil.FileNoMMap `state:"nosave"` + fsutil.FileNoSplice `state:"nosave"` + fsutil.FileNoopRelease `state:"nosave"` + fsutil.FileNoopFlush `state:"nosave"` + fsutil.FileNoopFsync `state:"nosave"` + fsutil.FileNotDirReaddir `state:"nosave"` + fsutil.FileUseInodeUnstableAttr `state:"nosave"` + waiter.AlwaysReady `state:"nosave"` + + tcpRecovery *tcpRecovery + + stack inet.Stack `state:"wait"` +} + +// Read implements fs.FileOperations.Read. +func (f *tcpRecoveryFile) Read(ctx context.Context, _ *fs.File, dst usermem.IOSequence, offset int64) (int64, error) { + if offset != 0 { + return 0, io.EOF + } + + recovery, err := f.stack.TCPRecovery() + if err != nil { + return 0, err + } + f.tcpRecovery.recovery = recovery + s := fmt.Sprintf("%d\n", f.tcpRecovery.recovery) + n, err := dst.CopyOut(ctx, []byte(s)) + return int64(n), err +} + +// Write implements fs.FileOperations.Write. +func (f *tcpRecoveryFile) Write(ctx context.Context, _ *fs.File, src usermem.IOSequence, offset int64) (int64, error) { + if src.NumBytes() == 0 { + return 0, nil + } + src = src.TakeFirst(usermem.PageSize - 1) + + var v int32 + n, err := usermem.CopyInt32StringInVec(ctx, src.IO, src.Addrs, &v, src.Opts) + if err != nil { + return 0, err + } + f.tcpRecovery.recovery = inet.TCPLossRecovery(v) + if err := f.tcpRecovery.stack.SetTCPRecovery(f.tcpRecovery.recovery); err != nil { + return 0, err + } + return n, nil +} + func (p *proc) newSysNetCore(ctx context.Context, msrc *fs.MountSource, s inet.Stack) *fs.Inode { // The following files are simple stubs until they are implemented in // netstack, most of these files are configuration related. We use the @@ -351,6 +441,11 @@ func (p *proc) newSysNetIPv4Dir(ctx context.Context, msrc *fs.MountSource, s ine contents["tcp_wmem"] = newTCPMemInode(ctx, msrc, s, tcpWMem) } + // Add tcp_recovery. + if _, err := s.TCPRecovery(); err == nil { + contents["tcp_recovery"] = newTCPRecoveryInode(ctx, msrc, s) + } + d := ramfs.NewDir(ctx, contents, fs.RootOwner, fs.FilePermsFromMode(0555)) return newProcInode(ctx, d, msrc, fs.SpecialDirectory, nil) } diff --git a/pkg/sentry/fsimpl/proc/tasks_sys.go b/pkg/sentry/fsimpl/proc/tasks_sys.go index 6dac2afa4..b71778128 100644 --- a/pkg/sentry/fsimpl/proc/tasks_sys.go +++ b/pkg/sentry/fsimpl/proc/tasks_sys.go @@ -55,7 +55,8 @@ func (fs *filesystem) newSysNetDir(root *auth.Credentials, k *kernel.Kernel) *ke if stack := k.RootNetworkNamespace().Stack(); stack != nil { contents = map[string]*kernfs.Dentry{ "ipv4": kernfs.NewStaticDir(root, linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), 0555, map[string]*kernfs.Dentry{ - "tcp_sack": fs.newDentry(root, fs.NextIno(), 0644, &tcpSackData{stack: stack}), + "tcp_recovery": fs.newDentry(root, fs.NextIno(), 0644, &tcpRecoveryData{stack: stack}), + "tcp_sack": fs.newDentry(root, fs.NextIno(), 0644, &tcpSackData{stack: stack}), // The following files are simple stubs until they are implemented in // netstack, most of these files are configuration related. We use the @@ -207,3 +208,49 @@ func (d *tcpSackData) Write(ctx context.Context, src usermem.IOSequence, offset *d.enabled = v != 0 return n, d.stack.SetTCPSACKEnabled(*d.enabled) } + +// tcpRecoveryData implements vfs.WritableDynamicBytesSource for +// /proc/sys/net/ipv4/tcp_recovery. +// +// +stateify savable +type tcpRecoveryData struct { + kernfs.DynamicBytesFile + + stack inet.Stack `state:"wait"` +} + +var _ vfs.WritableDynamicBytesSource = (*tcpRecoveryData)(nil) + +// Generate implements vfs.DynamicBytesSource. +func (d *tcpRecoveryData) Generate(ctx context.Context, buf *bytes.Buffer) error { + recovery, err := d.stack.TCPRecovery() + if err != nil { + return err + } + + buf.WriteString(fmt.Sprintf("%d\n", recovery)) + return nil +} + +func (d *tcpRecoveryData) Write(ctx context.Context, src usermem.IOSequence, offset int64) (int64, error) { + if offset != 0 { + // No need to handle partial writes thus far. + return 0, syserror.EINVAL + } + if src.NumBytes() == 0 { + return 0, nil + } + + // Limit the amount of memory allocated. + src = src.TakeFirst(usermem.PageSize - 1) + + var v int32 + n, err := usermem.CopyInt32StringInVec(ctx, src.IO, src.Addrs, &v, src.Opts) + if err != nil { + return 0, err + } + if err := d.stack.SetTCPRecovery(inet.TCPLossRecovery(v)); err != nil { + return 0, err + } + return n, nil +} diff --git a/pkg/sentry/inet/inet.go b/pkg/sentry/inet/inet.go index 2916a0644..c0b4831d1 100644 --- a/pkg/sentry/inet/inet.go +++ b/pkg/sentry/inet/inet.go @@ -56,6 +56,12 @@ type Stack interface { // settings. SetTCPSACKEnabled(enabled bool) error + // TCPRecovery returns the TCP loss detection algorithm. + TCPRecovery() (TCPLossRecovery, error) + + // SetTCPRecovery attempts to change TCP loss detection algorithm. + SetTCPRecovery(recovery TCPLossRecovery) error + // Statistics reports stack statistics. Statistics(stat interface{}, arg string) error @@ -189,3 +195,14 @@ type StatSNMPUDP [8]uint64 // StatSNMPUDPLite describes UdpLite line of /proc/net/snmp. type StatSNMPUDPLite [8]uint64 + +// TCPLossRecovery indicates TCP loss detection and recovery methods to use. +type TCPLossRecovery int32 + +// Loss recovery constants from include/net/tcp.h which are used to set +// /proc/sys/net/ipv4/tcp_recovery. +const ( + TCP_RACK_LOSS_DETECTION TCPLossRecovery = 1 << iota + TCP_RACK_STATIC_REO_WND + TCP_RACK_NO_DUPTHRESH +) diff --git a/pkg/sentry/inet/test_stack.go b/pkg/sentry/inet/test_stack.go index d8961fc94..9771f01fc 100644 --- a/pkg/sentry/inet/test_stack.go +++ b/pkg/sentry/inet/test_stack.go @@ -25,6 +25,7 @@ type TestStack struct { TCPRecvBufSize TCPBufferSize TCPSendBufSize TCPBufferSize TCPSACKFlag bool + Recovery TCPLossRecovery } // NewTestStack returns a TestStack with no network interfaces. The value of @@ -91,6 +92,17 @@ func (s *TestStack) SetTCPSACKEnabled(enabled bool) error { return nil } +// TCPRecovery implements Stack.TCPRecovery. +func (s *TestStack) TCPRecovery() (TCPLossRecovery, error) { + return s.Recovery, nil +} + +// SetTCPRecovery implements Stack.SetTCPRecovery. +func (s *TestStack) SetTCPRecovery(recovery TCPLossRecovery) error { + s.Recovery = recovery + return nil +} + // Statistics implements inet.Stack.Statistics. func (s *TestStack) Statistics(stat interface{}, arg string) error { return nil diff --git a/pkg/sentry/socket/hostinet/stack.go b/pkg/sentry/socket/hostinet/stack.go index a48082631..fda3dcb35 100644 --- a/pkg/sentry/socket/hostinet/stack.go +++ b/pkg/sentry/socket/hostinet/stack.go @@ -53,6 +53,7 @@ type Stack struct { interfaceAddrs map[int32][]inet.InterfaceAddr routes []inet.Route supportsIPv6 bool + tcpRecovery inet.TCPLossRecovery tcpRecvBufSize inet.TCPBufferSize tcpSendBufSize inet.TCPBufferSize tcpSACKEnabled bool @@ -350,6 +351,16 @@ func (s *Stack) SetTCPSACKEnabled(enabled bool) error { return syserror.EACCES } +// TCPRecovery implements inet.Stack.TCPRecovery. +func (s *Stack) TCPRecovery() (inet.TCPLossRecovery, error) { + return s.tcpRecovery, nil +} + +// SetTCPRecovery implements inet.Stack.SetTCPRecovery. +func (s *Stack) SetTCPRecovery(recovery inet.TCPLossRecovery) error { + return syserror.EACCES +} + // getLine reads one line from proc file, with specified prefix. // The last argument, withHeader, specifies if it contains line header. func getLine(f *os.File, prefix string, withHeader bool) string { diff --git a/pkg/sentry/socket/netstack/stack.go b/pkg/sentry/socket/netstack/stack.go index 67737ae87..f0fe18684 100644 --- a/pkg/sentry/socket/netstack/stack.go +++ b/pkg/sentry/socket/netstack/stack.go @@ -207,6 +207,20 @@ func (s *Stack) SetTCPSACKEnabled(enabled bool) error { return syserr.TranslateNetstackError(s.Stack.SetTransportProtocolOption(tcp.ProtocolNumber, tcp.SACKEnabled(enabled))).ToError() } +// TCPRecovery implements inet.Stack.TCPRecovery. +func (s *Stack) TCPRecovery() (inet.TCPLossRecovery, error) { + var recovery tcp.Recovery + if err := s.Stack.TransportProtocolOption(tcp.ProtocolNumber, &recovery); err != nil { + return 0, syserr.TranslateNetstackError(err).ToError() + } + return inet.TCPLossRecovery(recovery), nil +} + +// SetTCPRecovery implements inet.Stack.SetTCPRecovery. +func (s *Stack) SetTCPRecovery(recovery inet.TCPLossRecovery) error { + return syserr.TranslateNetstackError(s.Stack.SetTransportProtocolOption(tcp.ProtocolNumber, tcp.Recovery(recovery))).ToError() +} + // Statistics implements inet.Stack.Statistics. func (s *Stack) Statistics(stat interface{}, arg string) error { switch stats := stat.(type) { diff --git a/pkg/tcpip/transport/tcp/protocol.go b/pkg/tcpip/transport/tcp/protocol.go index b34e47bbd..d9abb8d94 100644 --- a/pkg/tcpip/transport/tcp/protocol.go +++ b/pkg/tcpip/transport/tcp/protocol.go @@ -80,6 +80,25 @@ const ( // enable/disable SACK support in TCP. See: https://tools.ietf.org/html/rfc2018. type SACKEnabled bool +// Recovery is used by stack.(*Stack).TransportProtocolOption to +// set loss detection algorithm in TCP. +type Recovery int32 + +const ( + // RACKLossDetection indicates RACK is used for loss detection and + // recovery. + RACKLossDetection Recovery = 1 << iota + + // RACKStaticReoWnd indicates the reordering window should not be + // adjusted when DSACK is received. + RACKStaticReoWnd + + // RACKNoDupTh indicates RACK should not consider the classic three + // duplicate acknowledgements rule to mark the segments as lost. This + // is used when reordering is not detected. + RACKNoDupTh +) + // DelayEnabled is used by stack.(Stack*).TransportProtocolOption to // enable/disable Nagle's algorithm in TCP. type DelayEnabled bool @@ -161,6 +180,7 @@ func (s *synRcvdCounter) Threshold() uint64 { type protocol struct { mu sync.RWMutex sackEnabled bool + recovery Recovery delayEnabled bool sendBufferSize SendBufferSizeOption recvBufferSize ReceiveBufferSizeOption @@ -280,6 +300,12 @@ func (p *protocol) SetOption(option interface{}) *tcpip.Error { p.mu.Unlock() return nil + case Recovery: + p.mu.Lock() + p.recovery = Recovery(v) + p.mu.Unlock() + return nil + case DelayEnabled: p.mu.Lock() p.delayEnabled = bool(v) @@ -394,6 +420,12 @@ func (p *protocol) Option(option interface{}) *tcpip.Error { p.mu.RUnlock() return nil + case *Recovery: + p.mu.RLock() + *v = Recovery(p.recovery) + p.mu.RUnlock() + return nil + case *DelayEnabled: p.mu.RLock() *v = DelayEnabled(p.delayEnabled) @@ -535,6 +567,7 @@ func NewProtocol() stack.TransportProtocol { minRTO: MinRTO, maxRTO: MaxRTO, maxRetries: MaxRetries, + recovery: RACKLossDetection, } p.dispatcher.init(runtime.GOMAXPROCS(0)) return &p diff --git a/test/syscalls/linux/proc_net.cc b/test/syscalls/linux/proc_net.cc index 3377b65cf..4fab097f4 100644 --- a/test/syscalls/linux/proc_net.cc +++ b/test/syscalls/linux/proc_net.cc @@ -477,6 +477,44 @@ TEST(ProcNetSnmp, CheckSnmp) { EXPECT_EQ(value_count, 1); } +TEST(ProcSysNetIpv4Recovery, Exists) { + EXPECT_THAT(open("/proc/sys/net/ipv4/tcp_recovery", O_RDONLY), + SyscallSucceeds()); +} + +TEST(ProcSysNetIpv4Recovery, CanReadAndWrite) { + // TODO(b/162988252): Enable save/restore for this test after the bug is + // fixed. + DisableSave ds; + + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability((CAP_DAC_OVERRIDE)))); + + auto const fd = ASSERT_NO_ERRNO_AND_VALUE( + Open("/proc/sys/net/ipv4/tcp_recovery", O_RDWR)); + + char buf[10] = {'\0'}; + char to_write = '2'; + + // Check initial value is set to 1. + EXPECT_THAT(PreadFd(fd.get(), &buf, sizeof(buf), 0), + SyscallSucceedsWithValue(sizeof(to_write) + 1)); + EXPECT_EQ(strcmp(buf, "1\n"), 0); + + // Set tcp_recovery to one of the allowed constants. + EXPECT_THAT(PwriteFd(fd.get(), &to_write, sizeof(to_write), 0), + SyscallSucceedsWithValue(sizeof(to_write))); + EXPECT_THAT(PreadFd(fd.get(), &buf, sizeof(buf), 0), + SyscallSucceedsWithValue(sizeof(to_write) + 1)); + EXPECT_EQ(strcmp(buf, "2\n"), 0); + + // Set tcp_recovery to any random value. + char kMessage[] = "100"; + EXPECT_THAT(PwriteFd(fd.get(), kMessage, strlen(kMessage), 0), + SyscallSucceedsWithValue(strlen(kMessage))); + EXPECT_THAT(PreadFd(fd.get(), buf, sizeof(kMessage), 0), + SyscallSucceedsWithValue(sizeof(kMessage))); + EXPECT_EQ(strcmp(buf, "100\n"), 0); +} } // namespace } // namespace testing } // namespace gvisor -- cgit v1.2.3