diff options
author | Ian Lewis <ianmlewis@gmail.com> | 2020-08-17 21:44:31 -0400 |
---|---|---|
committer | Ian Lewis <ianmlewis@gmail.com> | 2020-08-17 21:44:31 -0400 |
commit | ac324f646ee3cb7955b0b45a7453aeb9671cbdf1 (patch) | |
tree | 0cbc5018e8807421d701d190dc20525726c7ca76 /pkg/sentry/socket/netlink | |
parent | 352ae1022ce19de28fc72e034cc469872ad79d06 (diff) | |
parent | 6d0c5803d557d453f15ac6f683697eeb46dab680 (diff) |
Merge branch 'master' into ip-forwarding
- Merges aleksej-paschenko's with HEAD
- Adds vfs2 support for ip_forward
Diffstat (limited to 'pkg/sentry/socket/netlink')
-rw-r--r-- | pkg/sentry/socket/netlink/BUILD | 29 | ||||
-rw-r--r-- | pkg/sentry/socket/netlink/message.go | 136 | ||||
-rw-r--r-- | pkg/sentry/socket/netlink/message_test.go | 312 | ||||
-rw-r--r-- | pkg/sentry/socket/netlink/port/BUILD | 7 | ||||
-rw-r--r-- | pkg/sentry/socket/netlink/port/port.go | 3 | ||||
-rw-r--r-- | pkg/sentry/socket/netlink/provider.go | 18 | ||||
-rw-r--r-- | pkg/sentry/socket/netlink/provider_vfs2.go | 69 | ||||
-rw-r--r-- | pkg/sentry/socket/netlink/route/BUILD | 9 | ||||
-rw-r--r-- | pkg/sentry/socket/netlink/route/protocol.go | 339 | ||||
-rw-r--r-- | pkg/sentry/socket/netlink/socket.go | 291 | ||||
-rw-r--r-- | pkg/sentry/socket/netlink/socket_vfs2.go | 152 | ||||
-rw-r--r-- | pkg/sentry/socket/netlink/uevent/BUILD | 16 | ||||
-rw-r--r-- | pkg/sentry/socket/netlink/uevent/protocol.go | 60 |
13 files changed, 1279 insertions, 162 deletions
diff --git a/pkg/sentry/socket/netlink/BUILD b/pkg/sentry/socket/netlink/BUILD index f95803f91..0546801bf 100644 --- a/pkg/sentry/socket/netlink/BUILD +++ b/pkg/sentry/socket/netlink/BUILD @@ -1,4 +1,4 @@ -load("//tools/go_stateify:defs.bzl", "go_library") +load("//tools:defs.bzl", "go_library", "go_test") package(licenses = ["notice"]) @@ -7,29 +7,48 @@ go_library( srcs = [ "message.go", "provider.go", + "provider_vfs2.go", "socket.go", + "socket_vfs2.go", ], - importpath = "gvisor.dev/gvisor/pkg/sentry/socket/netlink", visibility = ["//pkg/sentry:internal"], deps = [ "//pkg/abi/linux", "//pkg/binary", + "//pkg/context", "//pkg/sentry/arch", - "//pkg/sentry/context", "//pkg/sentry/device", "//pkg/sentry/fs", "//pkg/sentry/fs/fsutil", + "//pkg/sentry/fs/lock", + "//pkg/sentry/fsimpl/sockfs", "//pkg/sentry/kernel", + "//pkg/sentry/kernel/auth", "//pkg/sentry/kernel/time", - "//pkg/sentry/safemem", "//pkg/sentry/socket", "//pkg/sentry/socket/netlink/port", "//pkg/sentry/socket/unix", "//pkg/sentry/socket/unix/transport", - "//pkg/sentry/usermem", + "//pkg/sentry/vfs", + "//pkg/sync", "//pkg/syserr", "//pkg/syserror", "//pkg/tcpip", + "//pkg/usermem", "//pkg/waiter", + "//tools/go_marshal/marshal", + "//tools/go_marshal/primitive", + ], +) + +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 ce0a1afd0..0899c61d1 100644 --- a/pkg/sentry/socket/netlink/message.go +++ b/pkg/sentry/socket/netlink/message.go @@ -20,18 +20,19 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/binary" - "gvisor.dev/gvisor/pkg/sentry/usermem" + "gvisor.dev/gvisor/pkg/usermem" ) -// alignUp rounds a length up to an alignment. +// alignPad returns the length of padding required for alignment. // // Preconditions: align is a power of two. -func alignUp(length int, align uint) int { - return (length + int(align) - 1) &^ (int(align) - 1) +func alignPad(length int, align uint) int { + return binary.AlignUp(length, align) - length } // Message contains a complete serialized netlink message. type Message struct { + hdr linux.NetlinkMessageHeader buf []byte } @@ -40,10 +41,86 @@ 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. @@ -54,7 +131,7 @@ func (m *Message) Finalize() []byte { // Align the message. Note that the message length in the header (set // above) is the useful length of the message, not the total aligned // length. See net/netlink/af_netlink.c:__nlmsg_put. - aligned := alignUp(len(m.buf), linux.NLMSG_ALIGNTO) + aligned := binary.AlignUp(len(m.buf), linux.NLMSG_ALIGNTO) m.putZeros(aligned - len(m.buf)) return m.buf } @@ -89,7 +166,7 @@ func (m *Message) PutAttr(atype uint16, v interface{}) { m.Put(v) // Align the attribute. - aligned := alignUp(l, linux.NLA_ALIGNTO) + aligned := binary.AlignUp(l, linux.NLA_ALIGNTO) m.putZeros(aligned - l) } @@ -106,7 +183,7 @@ func (m *Message) PutAttrString(atype uint16, s string) { m.putZeros(1) // Align the attribute. - aligned := alignUp(l, linux.NLA_ALIGNTO) + aligned := binary.AlignUp(l, linux.NLA_ALIGNTO) m.putZeros(aligned - l) } @@ -157,3 +234,48 @@ 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/port/BUILD b/pkg/sentry/socket/netlink/port/BUILD index 463544c1a..3a22923d8 100644 --- a/pkg/sentry/socket/netlink/port/BUILD +++ b/pkg/sentry/socket/netlink/port/BUILD @@ -1,17 +1,16 @@ -load("@io_bazel_rules_go//go:def.bzl", "go_test") -load("//tools/go_stateify:defs.bzl", "go_library") +load("//tools:defs.bzl", "go_library", "go_test") package(licenses = ["notice"]) go_library( name = "port", srcs = ["port.go"], - importpath = "gvisor.dev/gvisor/pkg/sentry/socket/netlink/port", visibility = ["//pkg/sentry:internal"], + deps = ["//pkg/sync"], ) go_test( name = "port_test", srcs = ["port_test.go"], - embed = [":port"], + library = ":port", ) diff --git a/pkg/sentry/socket/netlink/port/port.go b/pkg/sentry/socket/netlink/port/port.go index e9d3275b1..2cd3afc22 100644 --- a/pkg/sentry/socket/netlink/port/port.go +++ b/pkg/sentry/socket/netlink/port/port.go @@ -24,7 +24,8 @@ import ( "fmt" "math" "math/rand" - "sync" + + "gvisor.dev/gvisor/pkg/sync" ) // maxPorts is a sanity limit on the maximum number of ports to allocate per diff --git a/pkg/sentry/socket/netlink/provider.go b/pkg/sentry/socket/netlink/provider.go index 689cad997..31e374833 100644 --- a/pkg/sentry/socket/netlink/provider.go +++ b/pkg/sentry/socket/netlink/provider.go @@ -18,7 +18,7 @@ import ( "fmt" "gvisor.dev/gvisor/pkg/abi/linux" - "gvisor.dev/gvisor/pkg/sentry/context" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/sentry/socket" @@ -30,12 +30,19 @@ type Protocol interface { // Protocol returns the Linux netlink protocol value. Protocol() int + // CanSend returns true if this protocol may ever send messages. + // + // TODO(gvisor.dev/issue/1119): This is a workaround to allow + // advertising support for otherwise unimplemented features on sockets + // that will never send messages, thus making those features no-ops. + CanSend() bool + // ProcessMessage processes a single message from userspace. // // 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 @@ -60,6 +67,8 @@ func RegisterProvider(protocol int, provider Provider) { protocols[protocol] = provider } +// LINT.IfChange + // socketProvider implements socket.Provider. type socketProvider struct { } @@ -88,7 +97,7 @@ func (*socketProvider) Socket(t *kernel.Task, stype linux.SockType, protocol int } d := socket.NewDirent(t, netlinkSocketDevice) - defer d.DecRef() + defer d.DecRef(t) return fs.NewFile(t, d, fs.FileFlags{Read: true, Write: true, NonSeekable: true}, s), nil } @@ -98,7 +107,10 @@ func (*socketProvider) Pair(*kernel.Task, linux.SockType, int) (*fs.File, *fs.Fi return nil, nil, syserr.ErrNotSupported } +// LINT.ThenChange(./provider_vfs2.go) + // init registers the socket provider. func init() { socket.RegisterProvider(linux.AF_NETLINK, &socketProvider{}) + socket.RegisterProviderVFS2(linux.AF_NETLINK, &socketProviderVFS2{}) } diff --git a/pkg/sentry/socket/netlink/provider_vfs2.go b/pkg/sentry/socket/netlink/provider_vfs2.go new file mode 100644 index 000000000..bb205be0d --- /dev/null +++ b/pkg/sentry/socket/netlink/provider_vfs2.go @@ -0,0 +1,69 @@ +// Copyright 2018 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 netlink + +import ( + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/sentry/fsimpl/sockfs" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserr" +) + +// socketProviderVFS2 implements socket.Provider. +type socketProviderVFS2 struct { +} + +// Socket implements socket.Provider.Socket. +func (*socketProviderVFS2) Socket(t *kernel.Task, stype linux.SockType, protocol int) (*vfs.FileDescription, *syserr.Error) { + // Netlink sockets must be specified as datagram or raw, but they + // behave the same regardless of type. + if stype != linux.SOCK_DGRAM && stype != linux.SOCK_RAW { + return nil, syserr.ErrSocketNotSupported + } + + provider, ok := protocols[protocol] + if !ok { + return nil, syserr.ErrProtocolNotSupported + } + + p, err := provider(t) + if err != nil { + return nil, err + } + + s, err := NewVFS2(t, stype, p) + if err != nil { + return nil, err + } + + vfsfd := &s.vfsfd + mnt := t.Kernel().SocketMount() + d := sockfs.NewDentry(t.Credentials(), mnt) + if err := vfsfd.Init(s, linux.O_RDWR, mnt, d, &vfs.FileDescriptionOptions{ + DenyPRead: true, + DenyPWrite: true, + UseDentryMetadata: true, + }); err != nil { + return nil, syserr.FromError(err) + } + return vfsfd, nil +} + +// Pair implements socket.Provider.Pair by returning an error. +func (*socketProviderVFS2) Pair(*kernel.Task, linux.SockType, int) (*vfs.FileDescription, *vfs.FileDescription, *syserr.Error) { + // Netlink sockets never supports creating socket pairs. + return nil, nil, syserr.ErrNotSupported +} diff --git a/pkg/sentry/socket/netlink/route/BUILD b/pkg/sentry/socket/netlink/route/BUILD index 1d4912753..93127398d 100644 --- a/pkg/sentry/socket/netlink/route/BUILD +++ b/pkg/sentry/socket/netlink/route/BUILD @@ -1,15 +1,16 @@ -load("//tools/go_stateify:defs.bzl", "go_library") +load("//tools:defs.bzl", "go_library") package(licenses = ["notice"]) go_library( name = "route", - srcs = ["protocol.go"], - importpath = "gvisor.dev/gvisor/pkg/sentry/socket/netlink/route", + srcs = [ + "protocol.go", + ], visibility = ["//pkg/sentry:internal"], deps = [ "//pkg/abi/linux", - "//pkg/sentry/context", + "//pkg/context", "//pkg/sentry/inet", "//pkg/sentry/kernel", "//pkg/sentry/kernel/auth", diff --git a/pkg/sentry/socket/netlink/route/protocol.go b/pkg/sentry/socket/netlink/route/protocol.go index cc70ac237..c84d8bd7c 100644 --- a/pkg/sentry/socket/netlink/route/protocol.go +++ b/pkg/sentry/socket/netlink/route/protocol.go @@ -17,9 +17,10 @@ package route import ( "bytes" + "syscall" "gvisor.dev/gvisor/pkg/abi/linux" - "gvisor.dev/gvisor/pkg/sentry/context" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/inet" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" @@ -61,8 +62,13 @@ func (p *Protocol) Protocol() int { return linux.NETLINK_ROUTE } -// dumpLinks handles RTM_GETLINK + NLM_F_DUMP requests. -func (p *Protocol) dumpLinks(ctx context.Context, hdr linux.NetlinkMessageHeader, data []byte, ms *netlink.MessageSet) *syserr.Error { +// CanSend implements netlink.Protocol.CanSend. +func (p *Protocol) CanSend() bool { + return true +} + +// dumpLinks handles RTM_GETLINK dump requests. +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. @@ -86,38 +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 + NLM_F_DUMP requests. -func (p *Protocol) dumpAddrs(ctx context.Context, hdr linux.NetlinkMessageHeader, data []byte, ms *netlink.MessageSet) *syserr.Error { +// 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. @@ -149,6 +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. @@ -158,22 +232,136 @@ func (p *Protocol) dumpAddrs(ctx context.Context, hdr linux.NetlinkMessageHeader return nil } -// dumpRoutes handles RTM_GETROUTE + NLM_F_DUMP requests. -func (p *Protocol) dumpRoutes(ctx context.Context, hdr linux.NetlinkMessageHeader, data []byte, ms *netlink.MessageSet) *syserr.Error { +// commonPrefixLen reports the length of the longest IP address prefix. +// This is a simplied version from Golang's src/net/addrselect.go. +func commonPrefixLen(a, b []byte) (cpl int) { + for len(a) > 0 { + if a[0] == b[0] { + cpl += 8 + a = a[1:] + b = b[1:] + continue + } + bits := 8 + ab, bb := a[0], b[0] + for { + ab >>= 1 + bb >>= 1 + bits-- + if ab == bb { + cpl += bits + return + } + } + } + return +} + +// fillRoute returns the Route using LPM algorithm. Refer to Linux's +// net/ipv4/route.c:rt_fill_info(). +func fillRoute(routes []inet.Route, addr []byte) (inet.Route, *syserr.Error) { + family := uint8(linux.AF_INET) + if len(addr) != 4 { + family = linux.AF_INET6 + } + + idx := -1 // Index of the Route rule to be returned. + idxDef := -1 // Index of the default route rule. + prefix := 0 // Current longest prefix. + for i, route := range routes { + if route.Family != family { + continue + } + + if len(route.GatewayAddr) > 0 && route.DstLen == 0 { + idxDef = i + continue + } + + cpl := commonPrefixLen(addr, route.DstAddr) + if cpl < int(route.DstLen) { + continue + } + cpl = int(route.DstLen) + if cpl > prefix { + idx = i + prefix = cpl + } + } + if idx == -1 { + idx = idxDef + } + if idx == -1 { + return inet.Route{}, syserr.ErrNoRoute + } + + route := routes[idx] + if family == linux.AF_INET { + route.DstLen = 32 + } else { + route.DstLen = 128 + } + route.DstAddr = addr + route.Flags |= linux.RTM_F_CLONED // This route is cloned. + return route, nil +} + +// parseForDestination parses a message as format of RouteMessage-RtAttr-dst. +func parseForDestination(msg *netlink.Message) ([]byte, *syserr.Error) { + var rtMsg linux.RouteMessage + attrs, ok := msg.GetData(&rtMsg) + if !ok { + return nil, syserr.ErrInvalidArgument + } + // 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. + if rtMsg.Flags != 0 && rtMsg.Flags != linux.RTM_F_LOOKUP_TABLE { + return nil, syserr.ErrNotSupported + } + + // Expect first attribute is RTA_DST. + if hdr, value, _, ok := attrs.ParseFirst(); ok && hdr.Type == linux.RTA_DST { + return value, nil + } + return nil, syserr.ErrInvalidArgument +} + +// dumpRoutes handles RTM_GETROUTE requests. +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. - // We always send back an NLMSG_DONE. - ms.Multi = true - stack := inet.StackFromContext(ctx) if stack == nil { // No network routes. return nil } - for _, rt := range stack.RouteTable() { + hdr := msg.Header() + routeTables := stack.RouteTable() + + if hdr.Flags == linux.NLM_F_REQUEST { + dst, err := parseForDestination(msg) + if err != nil { + return err + } + route, err := fillRoute(routeTables, dst) + if err != nil { + // TODO(gvisor.dev/issue/1237): return NLMSG_ERROR with ENETUNREACH. + return syserr.ErrNotSupported + } + routeTables = append([]inet.Route{}, route) + } else if hdr.Flags&linux.NLM_F_DUMP == linux.NLM_F_DUMP { + // We always send back an NLMSG_DONE. + ms.Multi = true + } else { + // TODO(b/68878065): Only above cases are supported. + return syserr.ErrNotSupported + } + + for _, rt := range routeTables { m := ms.AddMessage(linux.NetlinkMessageHeader{ Type: linux.RTM_NEWROUTE, }) @@ -214,10 +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 @@ -231,22 +464,32 @@ func (p *Protocol) ProcessMessage(ctx context.Context, hdr linux.NetlinkMessageH } } - // 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 - } - - 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 b2732ca29..68a9b9a96 100644 --- a/pkg/sentry/socket/netlink/socket.go +++ b/pkg/sentry/socket/netlink/socket.go @@ -17,27 +17,29 @@ package netlink import ( "math" - "sync" "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/binary" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/arch" - "gvisor.dev/gvisor/pkg/sentry/context" "gvisor.dev/gvisor/pkg/sentry/device" "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/fs/fsutil" "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time" - "gvisor.dev/gvisor/pkg/sentry/safemem" "gvisor.dev/gvisor/pkg/sentry/socket" "gvisor.dev/gvisor/pkg/sentry/socket/netlink/port" "gvisor.dev/gvisor/pkg/sentry/socket/unix" "gvisor.dev/gvisor/pkg/sentry/socket/unix/transport" - "gvisor.dev/gvisor/pkg/sentry/usermem" + "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/syserr" "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/tcpip" + "gvisor.dev/gvisor/pkg/usermem" "gvisor.dev/gvisor/pkg/waiter" + "gvisor.dev/gvisor/tools/go_marshal/marshal" + "gvisor.dev/gvisor/tools/go_marshal/primitive" ) const sizeOfInt32 int = 4 @@ -53,15 +55,19 @@ const ( maxSendBufferSize = 4 << 20 // 4MB ) +var errNoFilter = syserr.New("no filter attached", linux.ENOENT) + // netlinkSocketDevice is the netlink socket virtual device. var netlinkSocketDevice = device.NewAnonDevice() +// LINT.IfChange + // Socket is the base socket type for netlink sockets. // // This implementation only supports userspace sending and receiving messages // to/from the kernel. // -// Socket implements socket.Socket. +// Socket implements socket.Socket and transport.Credentialer. // // +stateify savable type Socket struct { @@ -72,6 +78,14 @@ type Socket struct { fsutil.FileNoSplice `state:"nosave"` fsutil.FileNoopFlush `state:"nosave"` fsutil.FileUseInodeUnstableAttr `state:"nosave"` + + socketOpsCommon +} + +// socketOpsCommon contains the socket operations common to VFS1 and VFS2. +// +// +stateify savable +type socketOpsCommon struct { socket.SendReceiveTimeout // ports provides netlink port allocation. @@ -104,9 +118,19 @@ type Socket struct { // sendBufferSize is the send buffer "size". We don't actually have a // fixed buffer but only consume this many bytes. sendBufferSize uint32 + + // passcred indicates if this socket wants SCM credentials. + passcred bool + + // filter indicates that this socket has a BPF filter "installed". + // + // TODO(gvisor.dev/issue/1119): We don't actually support filtering, + // this is just bookkeeping for tracking add/remove. + filter bool } var _ socket.Socket = (*Socket)(nil) +var _ transport.Credentialer = (*Socket)(nil) // NewSocket creates a new Socket. func NewSocket(t *kernel.Task, skType linux.SockType, protocol Protocol) (*Socket, *syserr.Error) { @@ -116,31 +140,33 @@ func NewSocket(t *kernel.Task, skType linux.SockType, protocol Protocol) (*Socke // Bind the endpoint for good measure so we can connect to it. The // bound address will never be exposed. if err := ep.Bind(tcpip.FullAddress{Addr: "dummy"}, nil); err != nil { - ep.Close() + ep.Close(t) return nil, err } // Create a connection from which the kernel can write messages. connection, err := ep.(transport.BoundEndpoint).UnidirectionalConnect(t) if err != nil { - ep.Close() + ep.Close(t) return nil, err } return &Socket{ - ports: t.Kernel().NetlinkPorts(), - protocol: protocol, - skType: skType, - ep: ep, - connection: connection, - sendBufferSize: defaultSendBufferSize, + socketOpsCommon: socketOpsCommon{ + ports: t.Kernel().NetlinkPorts(), + protocol: protocol, + skType: skType, + ep: ep, + connection: connection, + sendBufferSize: defaultSendBufferSize, + }, }, nil } // Release implements fs.FileOperations.Release. -func (s *Socket) Release() { - s.connection.Release() - s.ep.Close() +func (s *socketOpsCommon) Release(ctx context.Context) { + s.connection.Release(ctx) + s.ep.Close(ctx) if s.bound { s.ports.Release(s.protocol.Protocol(), s.portID) @@ -148,7 +174,7 @@ func (s *Socket) Release() { } // Readiness implements waiter.Waitable.Readiness. -func (s *Socket) Readiness(mask waiter.EventMask) waiter.EventMask { +func (s *socketOpsCommon) Readiness(mask waiter.EventMask) waiter.EventMask { // ep holds messages to be read and thus handles EventIn readiness. ready := s.ep.Readiness(mask) @@ -162,16 +188,32 @@ func (s *Socket) Readiness(mask waiter.EventMask) waiter.EventMask { } // EventRegister implements waiter.Waitable.EventRegister. -func (s *Socket) EventRegister(e *waiter.Entry, mask waiter.EventMask) { +func (s *socketOpsCommon) EventRegister(e *waiter.Entry, mask waiter.EventMask) { s.ep.EventRegister(e, mask) // Writable readiness never changes, so no registration is needed. } // EventUnregister implements waiter.Waitable.EventUnregister. -func (s *Socket) EventUnregister(e *waiter.Entry) { +func (s *socketOpsCommon) EventUnregister(e *waiter.Entry) { s.ep.EventUnregister(e) } +// Passcred implements transport.Credentialer.Passcred. +func (s *socketOpsCommon) Passcred() bool { + s.mu.Lock() + passcred := s.passcred + s.mu.Unlock() + return passcred +} + +// ConnectedPasscred implements transport.Credentialer.ConnectedPasscred. +func (s *socketOpsCommon) ConnectedPasscred() bool { + // This socket is connected to the kernel, which doesn't need creds. + // + // This is arbitrary, as ConnectedPasscred on this type has no callers. + return false +} + // Ioctl implements fs.FileOperations.Ioctl. func (*Socket) Ioctl(context.Context, *fs.File, usermem.IO, arch.SyscallArguments) (uintptr, error) { // TODO(b/68878065): no ioctls supported. @@ -199,7 +241,7 @@ func ExtractSockAddr(b []byte) (*linux.SockAddrNetlink, *syserr.Error) { // port of 0 defaults to the ThreadGroup ID. // // Preconditions: mu is held. -func (s *Socket) bindPort(t *kernel.Task, port int32) *syserr.Error { +func (s *socketOpsCommon) bindPort(t *kernel.Task, port int32) *syserr.Error { if s.bound { // Re-binding is only allowed if the port doesn't change. if port != s.portID { @@ -223,7 +265,7 @@ func (s *Socket) bindPort(t *kernel.Task, port int32) *syserr.Error { } // Bind implements socket.Socket.Bind. -func (s *Socket) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error { +func (s *socketOpsCommon) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error { a, err := ExtractSockAddr(sockaddr) if err != nil { return err @@ -241,7 +283,7 @@ func (s *Socket) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error { } // Connect implements socket.Socket.Connect. -func (s *Socket) Connect(t *kernel.Task, sockaddr []byte, blocking bool) *syserr.Error { +func (s *socketOpsCommon) Connect(t *kernel.Task, sockaddr []byte, blocking bool) *syserr.Error { a, err := ExtractSockAddr(sockaddr) if err != nil { return err @@ -272,25 +314,25 @@ func (s *Socket) Connect(t *kernel.Task, sockaddr []byte, blocking bool) *syserr } // Accept implements socket.Socket.Accept. -func (s *Socket) Accept(t *kernel.Task, peerRequested bool, flags int, blocking bool) (int32, linux.SockAddr, uint32, *syserr.Error) { +func (s *socketOpsCommon) Accept(t *kernel.Task, peerRequested bool, flags int, blocking bool) (int32, linux.SockAddr, uint32, *syserr.Error) { // Netlink sockets never support accept. return 0, nil, 0, syserr.ErrNotSupported } // Listen implements socket.Socket.Listen. -func (s *Socket) Listen(t *kernel.Task, backlog int) *syserr.Error { +func (s *socketOpsCommon) Listen(t *kernel.Task, backlog int) *syserr.Error { // Netlink sockets never support listen. return syserr.ErrNotSupported } // Shutdown implements socket.Socket.Shutdown. -func (s *Socket) Shutdown(t *kernel.Task, how int) *syserr.Error { +func (s *socketOpsCommon) Shutdown(t *kernel.Task, how int) *syserr.Error { // Netlink sockets never support shutdown. return syserr.ErrNotSupported } // GetSockOpt implements socket.Socket.GetSockOpt. -func (s *Socket) GetSockOpt(t *kernel.Task, level int, name int, outPtr usermem.Addr, outLen int) (interface{}, *syserr.Error) { +func (s *socketOpsCommon) GetSockOpt(t *kernel.Task, level int, name int, outPtr usermem.Addr, outLen int) (marshal.Marshallable, *syserr.Error) { switch level { case linux.SOL_SOCKET: switch name { @@ -300,18 +342,31 @@ func (s *Socket) GetSockOpt(t *kernel.Task, level int, name int, outPtr usermem. } s.mu.Lock() defer s.mu.Unlock() - return int32(s.sendBufferSize), nil + sendBufferSizeP := primitive.Int32(s.sendBufferSize) + return &sendBufferSizeP, nil case linux.SO_RCVBUF: if outLen < sizeOfInt32 { return nil, syserr.ErrInvalidArgument } // We don't have limit on receiving size. - return int32(math.MaxInt32), nil + recvBufferSizeP := primitive.Int32(math.MaxInt32) + return &recvBufferSizeP, nil + + case linux.SO_PASSCRED: + if outLen < sizeOfInt32 { + return nil, syserr.ErrInvalidArgument + } + var passcred primitive.Int32 + if s.Passcred() { + passcred = 1 + } + return &passcred, nil default: socket.GetSockOptEmitUnimplementedEvent(t, name) } + case linux.SOL_NETLINK: switch name { case linux.NETLINK_BROADCAST_ERROR, @@ -330,7 +385,7 @@ func (s *Socket) GetSockOpt(t *kernel.Task, level int, name int, outPtr usermem. } // SetSockOpt implements socket.Socket.SetSockOpt. -func (s *Socket) SetSockOpt(t *kernel.Task, level int, name int, opt []byte) *syserr.Error { +func (s *socketOpsCommon) SetSockOpt(t *kernel.Task, level int, name int, opt []byte) *syserr.Error { switch level { case linux.SOL_SOCKET: switch name { @@ -348,6 +403,7 @@ func (s *Socket) SetSockOpt(t *kernel.Task, level int, name int, opt []byte) *sy s.sendBufferSize = size s.mu.Unlock() return nil + case linux.SO_RCVBUF: if len(opt) < sizeOfInt32 { return syserr.ErrInvalidArgument @@ -355,6 +411,52 @@ func (s *Socket) SetSockOpt(t *kernel.Task, level int, name int, opt []byte) *sy // We don't have limit on receiving size. So just accept anything as // valid for compatibility. return nil + + case linux.SO_PASSCRED: + if len(opt) < sizeOfInt32 { + return syserr.ErrInvalidArgument + } + passcred := usermem.ByteOrder.Uint32(opt) + + s.mu.Lock() + s.passcred = passcred != 0 + s.mu.Unlock() + return nil + + case linux.SO_ATTACH_FILTER: + // TODO(gvisor.dev/issue/1119): We don't actually + // support filtering. If this socket can't ever send + // messages, then there is nothing to filter and we can + // advertise support. Otherwise, be conservative and + // return an error. + if s.protocol.CanSend() { + socket.SetSockOptEmitUnimplementedEvent(t, name) + return syserr.ErrProtocolNotAvailable + } + + s.mu.Lock() + s.filter = true + s.mu.Unlock() + return nil + + case linux.SO_DETACH_FILTER: + // TODO(gvisor.dev/issue/1119): See above. + if s.protocol.CanSend() { + socket.SetSockOptEmitUnimplementedEvent(t, name) + return syserr.ErrProtocolNotAvailable + } + + s.mu.Lock() + filter := s.filter + s.filter = false + s.mu.Unlock() + + if !filter { + return errNoFilter + } + + return nil + default: socket.SetSockOptEmitUnimplementedEvent(t, name) } @@ -380,7 +482,7 @@ func (s *Socket) SetSockOpt(t *kernel.Task, level int, name int, opt []byte) *sy } // GetSockName implements socket.Socket.GetSockName. -func (s *Socket) GetSockName(t *kernel.Task) (linux.SockAddr, uint32, *syserr.Error) { +func (s *socketOpsCommon) GetSockName(t *kernel.Task) (linux.SockAddr, uint32, *syserr.Error) { s.mu.Lock() defer s.mu.Unlock() @@ -392,7 +494,7 @@ func (s *Socket) GetSockName(t *kernel.Task) (linux.SockAddr, uint32, *syserr.Er } // GetPeerName implements socket.Socket.GetPeerName. -func (s *Socket) GetPeerName(t *kernel.Task) (linux.SockAddr, uint32, *syserr.Error) { +func (s *socketOpsCommon) GetPeerName(t *kernel.Task) (linux.SockAddr, uint32, *syserr.Error) { sa := &linux.SockAddrNetlink{ Family: linux.AF_NETLINK, // TODO(b/68878065): Support non-kernel peers. For now the peer @@ -403,7 +505,7 @@ func (s *Socket) GetPeerName(t *kernel.Task) (linux.SockAddr, uint32, *syserr.Er } // RecvMsg implements socket.Socket.RecvMsg. -func (s *Socket) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags int, haveDeadline bool, deadline ktime.Time, senderRequested bool, controlDataLen uint64) (int, int, linux.SockAddr, uint32, socket.ControlMessages, *syserr.Error) { +func (s *socketOpsCommon) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags int, haveDeadline bool, deadline ktime.Time, senderRequested bool, controlDataLen uint64) (int, int, linux.SockAddr, uint32, socket.ControlMessages, *syserr.Error) { from := &linux.SockAddrNetlink{ Family: linux.AF_NETLINK, PortID: 0, @@ -413,29 +515,29 @@ func (s *Socket) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags int, have trunc := flags&linux.MSG_TRUNC != 0 r := unix.EndpointReader{ + Ctx: t, Endpoint: s.ep, Peek: flags&linux.MSG_PEEK != 0, } + doRead := func() (int64, error) { + return dst.CopyOutFrom(t, &r) + } + // If MSG_TRUNC is set with a zero byte destination then we still need // to read the message and discard it, or in the case where MSG_PEEK is // set, leave it be. In both cases the full message length must be - // returned. However, the memory manager for the destination will not read - // the endpoint if the destination is zero length. - // - // In order for the endpoint to be read when the destination size is zero, - // we must cause a read of the endpoint by using a separate fake zero - // length block sequence and calling the EndpointReader directly. + // returned. if trunc && dst.Addrs.NumBytes() == 0 { - // Perform a read to a zero byte block sequence. We can ignore the - // original destination since it was zero bytes. The length returned by - // ReadToBlocks is ignored and we return the full message length to comply - // with MSG_TRUNC. - _, err := r.ReadToBlocks(safemem.BlockSeqOf(safemem.BlockFromSafeSlice(make([]byte, 0)))) - return int(r.MsgSize), linux.MSG_TRUNC, from, fromLen, socket.ControlMessages{}, syserr.FromError(err) + doRead = func() (int64, error) { + err := r.Truncate() + // Always return zero for bytes read since the destination size is + // zero. + return 0, err + } } - if n, err := dst.CopyOutFrom(t, &r); err != syserror.ErrWouldBlock || flags&linux.MSG_DONTWAIT != 0 { + if n, err := doRead(); err != syserror.ErrWouldBlock || flags&linux.MSG_DONTWAIT != 0 { var mflags int if n < int64(r.MsgSize) { mflags |= linux.MSG_TRUNC @@ -453,7 +555,7 @@ func (s *Socket) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags int, have defer s.EventUnregister(&e) for { - if n, err := dst.CopyOutFrom(t, &r); err != syserror.ErrWouldBlock { + if n, err := doRead(); err != syserror.ErrWouldBlock { var mflags int if n < int64(r.MsgSize) { mflags |= linux.MSG_TRUNC @@ -483,18 +585,43 @@ func (s *Socket) Read(ctx context.Context, _ *fs.File, dst usermem.IOSequence, _ }) } +// kernelSCM implements control.SCMCredentials with credentials that represent +// the kernel itself rather than a Task. +// +// +stateify savable +type kernelSCM struct{} + +// Equals implements transport.CredentialsControlMessage.Equals. +func (kernelSCM) Equals(oc transport.CredentialsControlMessage) bool { + _, ok := oc.(kernelSCM) + return ok +} + +// Credentials implements control.SCMCredentials.Credentials. +func (kernelSCM) Credentials(*kernel.Task) (kernel.ThreadID, auth.UID, auth.GID) { + return 0, auth.RootUID, auth.RootGID +} + +// kernelCreds is the concrete version of kernelSCM used in all creds. +var kernelCreds = &kernelSCM{} + // sendResponse sends the response messages in ms back to userspace. -func (s *Socket) sendResponse(ctx context.Context, ms *MessageSet) *syserr.Error { +func (s *socketOpsCommon) sendResponse(ctx context.Context, ms *MessageSet) *syserr.Error { // Linux combines multiple netlink messages into a single datagram. bufs := make([][]byte, 0, len(ms.Messages)) for _, m := range ms.Messages { bufs = append(bufs, m.Finalize()) } + // All messages are from the kernel. + cms := transport.ControlMessages{ + Credentials: kernelCreds, + } + if len(bufs) > 0 { // RecvMsg never receives the address, so we don't need to send // one. - _, notify, err := s.connection.Send(bufs, transport.ControlMessages{}, tcpip.FullAddress{}) + _, notify, err := s.connection.Send(ctx, bufs, cms, tcpip.FullAddress{}) // If the buffer is full, we simply drop messages, just like // Linux. if err != nil && err != syserr.ErrWouldBlock { @@ -521,7 +648,7 @@ func (s *Socket) sendResponse(ctx context.Context, ms *MessageSet) *syserr.Error // Add the dump_done_errno payload. m.Put(int64(0)) - _, notify, err := s.connection.Send([][]byte{m.Finalize()}, transport.ControlMessages{}, tcpip.FullAddress{}) + _, notify, err := s.connection.Send(ctx, [][]byte{m.Finalize()}, cms, tcpip.FullAddress{}) if err != nil && err != syserr.ErrWouldBlock { return err } @@ -533,47 +660,38 @@ 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 { +func (s *socketOpsCommon) 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 { @@ -581,19 +699,10 @@ 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 { @@ -605,7 +714,7 @@ func (s *Socket) processMessages(ctx context.Context, buf []byte) *syserr.Error } // sendMsg is the core of message send, used for SendMsg and Write. -func (s *Socket) sendMsg(ctx context.Context, src usermem.IOSequence, to []byte, flags int, controlMessages socket.ControlMessages) (int, *syserr.Error) { +func (s *socketOpsCommon) sendMsg(ctx context.Context, src usermem.IOSequence, to []byte, flags int, controlMessages socket.ControlMessages) (int, *syserr.Error) { dstPort := int32(0) if len(to) != 0 { @@ -652,7 +761,7 @@ func (s *Socket) sendMsg(ctx context.Context, src usermem.IOSequence, to []byte, } // SendMsg implements socket.Socket.SendMsg. -func (s *Socket) SendMsg(t *kernel.Task, src usermem.IOSequence, to []byte, flags int, haveDeadline bool, deadline ktime.Time, controlMessages socket.ControlMessages) (int, *syserr.Error) { +func (s *socketOpsCommon) SendMsg(t *kernel.Task, src usermem.IOSequence, to []byte, flags int, haveDeadline bool, deadline ktime.Time, controlMessages socket.ControlMessages) (int, *syserr.Error) { return s.sendMsg(t, src, to, flags, controlMessages) } @@ -663,11 +772,13 @@ func (s *Socket) Write(ctx context.Context, _ *fs.File, src usermem.IOSequence, } // State implements socket.Socket.State. -func (s *Socket) State() uint32 { +func (s *socketOpsCommon) State() uint32 { return s.ep.State() } // Type implements socket.Socket.Type. -func (s *Socket) Type() (family int, skType linux.SockType, protocol int) { +func (s *socketOpsCommon) Type() (family int, skType linux.SockType, protocol int) { return linux.AF_NETLINK, s.skType, s.protocol.Protocol() } + +// LINT.ThenChange(./socket_vfs2.go) diff --git a/pkg/sentry/socket/netlink/socket_vfs2.go b/pkg/sentry/socket/netlink/socket_vfs2.go new file mode 100644 index 000000000..a38d25da9 --- /dev/null +++ b/pkg/sentry/socket/netlink/socket_vfs2.go @@ -0,0 +1,152 @@ +// Copyright 2018 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 netlink + +import ( + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/sentry/arch" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/socket" + "gvisor.dev/gvisor/pkg/sentry/socket/unix" + "gvisor.dev/gvisor/pkg/sentry/socket/unix/transport" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserr" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/tcpip" + "gvisor.dev/gvisor/pkg/usermem" + "gvisor.dev/gvisor/pkg/waiter" +) + +// SocketVFS2 is the base VFS2 socket type for netlink sockets. +// +// This implementation only supports userspace sending and receiving messages +// to/from the kernel. +// +// SocketVFS2 implements socket.SocketVFS2 and transport.Credentialer. +type SocketVFS2 struct { + vfsfd vfs.FileDescription + vfs.FileDescriptionDefaultImpl + vfs.DentryMetadataFileDescriptionImpl + vfs.LockFD + + socketOpsCommon +} + +var _ socket.SocketVFS2 = (*SocketVFS2)(nil) +var _ transport.Credentialer = (*SocketVFS2)(nil) + +// NewVFS2 creates a new SocketVFS2. +func NewVFS2(t *kernel.Task, skType linux.SockType, protocol Protocol) (*SocketVFS2, *syserr.Error) { + // Datagram endpoint used to buffer kernel -> user messages. + ep := transport.NewConnectionless(t) + + // Bind the endpoint for good measure so we can connect to it. The + // bound address will never be exposed. + if err := ep.Bind(tcpip.FullAddress{Addr: "dummy"}, nil); err != nil { + ep.Close(t) + return nil, err + } + + // Create a connection from which the kernel can write messages. + connection, err := ep.(transport.BoundEndpoint).UnidirectionalConnect(t) + if err != nil { + ep.Close(t) + return nil, err + } + + fd := &SocketVFS2{ + socketOpsCommon: socketOpsCommon{ + ports: t.Kernel().NetlinkPorts(), + protocol: protocol, + skType: skType, + ep: ep, + connection: connection, + sendBufferSize: defaultSendBufferSize, + }, + } + fd.LockFD.Init(&vfs.FileLocks{}) + return fd, nil +} + +// Readiness implements waiter.Waitable.Readiness. +func (s *SocketVFS2) Readiness(mask waiter.EventMask) waiter.EventMask { + return s.socketOpsCommon.Readiness(mask) +} + +// EventRegister implements waiter.Waitable.EventRegister. +func (s *SocketVFS2) EventRegister(e *waiter.Entry, mask waiter.EventMask) { + s.socketOpsCommon.EventRegister(e, mask) +} + +// EventUnregister implements waiter.Waitable.EventUnregister. +func (s *SocketVFS2) EventUnregister(e *waiter.Entry) { + s.socketOpsCommon.EventUnregister(e) +} + +// Ioctl implements vfs.FileDescriptionImpl. +func (*SocketVFS2) Ioctl(context.Context, usermem.IO, arch.SyscallArguments) (uintptr, error) { + // TODO(b/68878065): no ioctls supported. + return 0, syserror.ENOTTY +} + +// PRead implements vfs.FileDescriptionImpl. +func (s *SocketVFS2) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) { + return 0, syserror.ESPIPE +} + +// Read implements vfs.FileDescriptionImpl. +func (s *SocketVFS2) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) { + // All flags other than RWF_NOWAIT should be ignored. + // TODO(gvisor.dev/issue/2601): Support RWF_NOWAIT. + if opts.Flags != 0 { + return 0, syserror.EOPNOTSUPP + } + + if dst.NumBytes() == 0 { + return 0, nil + } + return dst.CopyOutFrom(ctx, &unix.EndpointReader{ + Endpoint: s.ep, + }) +} + +// PWrite implements vfs.FileDescriptionImpl. +func (s *SocketVFS2) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) { + return 0, syserror.ESPIPE +} + +// Write implements vfs.FileDescriptionImpl. +func (s *SocketVFS2) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) { + // All flags other than RWF_NOWAIT should be ignored. + // TODO(gvisor.dev/issue/2601): Support RWF_NOWAIT. + if opts.Flags != 0 { + return 0, syserror.EOPNOTSUPP + } + + n, err := s.sendMsg(ctx, src, nil, 0, socket.ControlMessages{}) + return int64(n), err.ToError() +} + +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (s *SocketVFS2) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return s.Locks().LockPOSIX(ctx, &s.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (s *SocketVFS2) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return s.Locks().UnlockPOSIX(ctx, &s.vfsfd, uid, start, length, whence) +} diff --git a/pkg/sentry/socket/netlink/uevent/BUILD b/pkg/sentry/socket/netlink/uevent/BUILD new file mode 100644 index 000000000..b6434923c --- /dev/null +++ b/pkg/sentry/socket/netlink/uevent/BUILD @@ -0,0 +1,16 @@ +load("//tools:defs.bzl", "go_library") + +package(licenses = ["notice"]) + +go_library( + name = "uevent", + srcs = ["protocol.go"], + visibility = ["//pkg/sentry:internal"], + deps = [ + "//pkg/abi/linux", + "//pkg/context", + "//pkg/sentry/kernel", + "//pkg/sentry/socket/netlink", + "//pkg/syserr", + ], +) diff --git a/pkg/sentry/socket/netlink/uevent/protocol.go b/pkg/sentry/socket/netlink/uevent/protocol.go new file mode 100644 index 000000000..029ba21b5 --- /dev/null +++ b/pkg/sentry/socket/netlink/uevent/protocol.go @@ -0,0 +1,60 @@ +// Copyright 2019 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 uevent provides a NETLINK_KOBJECT_UEVENT socket protocol. +// +// NETLINK_KOBJECT_UEVENT sockets send udev-style device events. gVisor does +// not support any device events, so these sockets never send any messages. +package uevent + +import ( + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/socket/netlink" + "gvisor.dev/gvisor/pkg/syserr" +) + +// Protocol implements netlink.Protocol. +// +// +stateify savable +type Protocol struct{} + +var _ netlink.Protocol = (*Protocol)(nil) + +// NewProtocol creates a NETLINK_KOBJECT_UEVENT netlink.Protocol. +func NewProtocol(t *kernel.Task) (netlink.Protocol, *syserr.Error) { + return &Protocol{}, nil +} + +// Protocol implements netlink.Protocol.Protocol. +func (p *Protocol) Protocol() int { + return linux.NETLINK_KOBJECT_UEVENT +} + +// CanSend implements netlink.Protocol.CanSend. +func (p *Protocol) CanSend() bool { + return false +} + +// ProcessMessage implements netlink.Protocol.ProcessMessage. +func (p *Protocol) ProcessMessage(ctx context.Context, msg *netlink.Message, ms *netlink.MessageSet) *syserr.Error { + // Silently ignore all messages. + return nil +} + +// init registers the NETLINK_KOBJECT_UEVENT provider. +func init() { + netlink.RegisterProvider(linux.NETLINK_KOBJECT_UEVENT, NewProtocol) +} |