1 files changed, 195 insertions, 0 deletions
diff --git a/pkg/sentry/socket/netstack/provider.go b/pkg/sentry/socket/netstack/provider.go
new file mode 100644
index 000000000..2d2c1ba2a
--- /dev/null
+++ b/pkg/sentry/socket/netstack/provider.go
@@ -0,0 +1,195 @@
+// 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 netstack
+
+import (
+	"syscall"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/sentry/fs"
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sentry/socket"
+	"gvisor.dev/gvisor/pkg/syserr"
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
+	"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
+	"gvisor.dev/gvisor/pkg/tcpip/network/ipv6"
+	"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
+	"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
+	"gvisor.dev/gvisor/pkg/waiter"
+)
+
+// provider is an inet socket provider.
+type provider struct {
+	family   int
+	netProto tcpip.NetworkProtocolNumber
+}
+
+// getTransportProtocol figures out transport protocol. Currently only TCP,
+// UDP, and ICMP are supported. The bool return value is true when this socket
+// is associated with a transport protocol. This is only false for SOCK_RAW,
+// IPPROTO_IP sockets.
+func getTransportProtocol(ctx context.Context, stype linux.SockType, protocol int) (tcpip.TransportProtocolNumber, bool, *syserr.Error) {
+	switch stype {
+	case linux.SOCK_STREAM:
+		if protocol != 0 && protocol != syscall.IPPROTO_TCP {
+			return 0, true, syserr.ErrInvalidArgument
+		}
+		return tcp.ProtocolNumber, true, nil
+
+	case linux.SOCK_DGRAM:
+		switch protocol {
+		case 0, syscall.IPPROTO_UDP:
+			return udp.ProtocolNumber, true, nil
+		case syscall.IPPROTO_ICMP:
+			return header.ICMPv4ProtocolNumber, true, nil
+		case syscall.IPPROTO_ICMPV6:
+			return header.ICMPv6ProtocolNumber, true, nil
+		}
+
+	case linux.SOCK_RAW:
+		// TODO(b/142504697): "In order to create a raw socket, a
+		// process must have the CAP_NET_RAW capability in the user
+		// namespace that governs its network namespace." - raw(7)
+
+		// Raw sockets require CAP_NET_RAW.
+		creds := auth.CredentialsFromContext(ctx)
+		if !creds.HasCapability(linux.CAP_NET_RAW) {
+			return 0, true, syserr.ErrNotPermitted
+		}
+
+		switch protocol {
+		case syscall.IPPROTO_ICMP:
+			return header.ICMPv4ProtocolNumber, true, nil
+		case syscall.IPPROTO_UDP:
+			return header.UDPProtocolNumber, true, nil
+		case syscall.IPPROTO_TCP:
+			return header.TCPProtocolNumber, true, nil
+		// IPPROTO_RAW signifies that the raw socket isn't assigned to
+		// a transport protocol. Users will be able to write packets'
+		// IP headers and won't receive anything.
+		case syscall.IPPROTO_RAW:
+			return tcpip.TransportProtocolNumber(0), false, nil
+		}
+	}
+	return 0, true, syserr.ErrProtocolNotSupported
+}
+
+// Socket creates a new socket object for the AF_INET, AF_INET6, or AF_PACKET
+// family.
+func (p *provider) Socket(t *kernel.Task, stype linux.SockType, protocol int) (*fs.File, *syserr.Error) {
+	// Fail right away if we don't have a stack.
+	stack := t.NetworkContext()
+	if stack == nil {
+		// Don't propagate an error here. Instead, allow the socket
+		// code to continue searching for another provider.
+		return nil, nil
+	}
+	eps, ok := stack.(*Stack)
+	if !ok {
+		return nil, nil
+	}
+
+	// Packet sockets are handled separately, since they are neither INET
+	// nor INET6 specific.
+	if p.family == linux.AF_PACKET {
+		return packetSocket(t, eps, stype, protocol)
+	}
+
+	// Figure out the transport protocol.
+	transProto, associated, err := getTransportProtocol(t, stype, protocol)
+	if err != nil {
+		return nil, err
+	}
+
+	// Create the endpoint.
+	var ep tcpip.Endpoint
+	var e *tcpip.Error
+	wq := &waiter.Queue{}
+	if stype == linux.SOCK_RAW {
+		ep, e = eps.Stack.NewRawEndpoint(transProto, p.netProto, wq, associated)
+	} else {
+		ep, e = eps.Stack.NewEndpoint(transProto, p.netProto, wq)
+	}
+	if e != nil {
+		return nil, syserr.TranslateNetstackError(e)
+	}
+
+	return New(t, p.family, stype, int(transProto), wq, ep)
+}
+
+func packetSocket(t *kernel.Task, epStack *Stack, stype linux.SockType, protocol int) (*fs.File, *syserr.Error) {
+	// TODO(b/142504697): "In order to create a packet socket, a process
+	// must have the CAP_NET_RAW capability in the user namespace that
+	// governs its network namespace." - packet(7)
+
+	// Packet sockets require CAP_NET_RAW.
+	creds := auth.CredentialsFromContext(t)
+	if !creds.HasCapability(linux.CAP_NET_RAW) {
+		return nil, syserr.ErrNotPermitted
+	}
+
+	// "cooked" packets don't contain link layer information.
+	var cooked bool
+	switch stype {
+	case linux.SOCK_DGRAM:
+		cooked = true
+	case linux.SOCK_RAW:
+		cooked = false
+	default:
+		return nil, syserr.ErrProtocolNotSupported
+	}
+
+	// protocol is passed in network byte order, but netstack wants it in
+	// host order.
+	netProto := tcpip.NetworkProtocolNumber(ntohs(uint16(protocol)))
+
+	wq := &waiter.Queue{}
+	ep, err := epStack.Stack.NewPacketEndpoint(cooked, netProto, wq)
+	if err != nil {
+		return nil, syserr.TranslateNetstackError(err)
+	}
+
+	return New(t, linux.AF_PACKET, stype, protocol, wq, ep)
+}
+
+// Pair just returns nil sockets (not supported).
+func (*provider) Pair(*kernel.Task, linux.SockType, int) (*fs.File, *fs.File, *syserr.Error) {
+	return nil, nil, nil
+}
+
+// init registers socket providers for AF_INET, AF_INET6, and AF_PACKET.
+func init() {
+	// Providers backed by netstack.
+	p := []provider{
+		{
+			family:   linux.AF_INET,
+			netProto: ipv4.ProtocolNumber,
+		},
+		{
+			family:   linux.AF_INET6,
+			netProto: ipv6.ProtocolNumber,
+		},
+		{
+			family: linux.AF_PACKET,
+		},
+	}
+
+	for i := range p {
+		socket.RegisterProvider(p[i].family, &p[i])
+	}
+}