Plumbing for iptables sockopts.

PiperOrigin-RevId: 261413396

11 files changed, 121 insertions, 9 deletions

diff --git a/pkg/sentry/socket/epsocket/BUILD b/pkg/sentry/socket/epsocket/BUILD
index 1f014f399..e927821e1 100644
--- a/pkg/sentry/socket/epsocket/BUILD
+++ b/pkg/sentry/socket/epsocket/BUILD
@@ -31,6 +31,7 @@ go_library(
         "//pkg/sentry/kernel/time",
         "//pkg/sentry/safemem",
         "//pkg/sentry/socket",
+        "//pkg/sentry/socket/netfilter",
         "//pkg/sentry/unimpl",
         "//pkg/sentry/usermem",
         "//pkg/syserr",
@@ -38,6 +39,7 @@ go_library(
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
         "//pkg/tcpip/header",
+        "//pkg/tcpip/iptables",
         "//pkg/tcpip/network/ipv4",
         "//pkg/tcpip/network/ipv6",
         "//pkg/tcpip/stack",
diff --git a/pkg/sentry/socket/epsocket/epsocket.go b/pkg/sentry/socket/epsocket/epsocket.go
index 0f483faa8..1a4442959 100644
--- a/pkg/sentry/socket/epsocket/epsocket.go
+++ b/pkg/sentry/socket/epsocket/epsocket.go
@@ -43,6 +43,7 @@ import (
 	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/netfilter"
 	"gvisor.dev/gvisor/pkg/sentry/unimpl"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
 	"gvisor.dev/gvisor/pkg/syserr"
@@ -624,7 +625,7 @@ func (s *SocketOperations) Shutdown(t *kernel.Task, how int) *syserr.Error {
 
 // GetSockOpt implements the linux syscall getsockopt(2) for sockets backed by
 // tcpip.Endpoint.
-func (s *SocketOperations) GetSockOpt(t *kernel.Task, level, name, outLen int) (interface{}, *syserr.Error) {
+func (s *SocketOperations) GetSockOpt(t *kernel.Task, level, name int, outPtr usermem.Addr, outLen int) (interface{}, *syserr.Error) {
 	// TODO(b/78348848): Unlike other socket options, SO_TIMESTAMP is
 	// implemented specifically for epsocket.SocketOperations rather than
 	// commonEndpoint. commonEndpoint should be extended to support socket
@@ -655,6 +656,33 @@ func (s *SocketOperations) GetSockOpt(t *kernel.Task, level, name, outLen int) (
 		return val, nil
 	}
 
+	if s.skType == linux.SOCK_RAW && level == linux.IPPROTO_IP {
+		switch name {
+		case linux.IPT_SO_GET_INFO:
+			if outLen < linux.SizeOfIPTGetinfo {
+				return nil, syserr.ErrInvalidArgument
+			}
+
+			info, err := netfilter.GetInfo(t, s.Endpoint, outPtr)
+			if err != nil {
+				return nil, err
+			}
+			return info, nil
+
+		case linux.IPT_SO_GET_ENTRIES:
+			if outLen < linux.SizeOfIPTGetEntries {
+				return nil, syserr.ErrInvalidArgument
+			}
+
+			entries, err := netfilter.GetEntries(t, s.Endpoint, outPtr, outLen)
+			if err != nil {
+				return nil, err
+			}
+			return entries, nil
+
+		}
+	}
+
 	return GetSockOpt(t, s, s.Endpoint, s.family, s.skType, level, name, outLen)
 }
 
diff --git a/pkg/sentry/socket/epsocket/stack.go b/pkg/sentry/socket/epsocket/stack.go
index 27774be33..0cf235b31 100644
--- a/pkg/sentry/socket/epsocket/stack.go
+++ b/pkg/sentry/socket/epsocket/stack.go
@@ -18,9 +18,11 @@ import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/inet"
+	"gvisor.dev/gvisor/pkg/sentry/socket/netfilter"
 	"gvisor.dev/gvisor/pkg/syserr"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
+	"gvisor.dev/gvisor/pkg/tcpip/iptables"
 	"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
 	"gvisor.dev/gvisor/pkg/tcpip/network/ipv6"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
@@ -188,3 +190,14 @@ func (s *Stack) RouteTable() []inet.Route {
 
 	return routeTable
 }
+
+// IPTables returns the stack's iptables.
+func (s *Stack) IPTables() (iptables.IPTables, error) {
+	return s.Stack.IPTables(), nil
+}
+
+// FillDefaultIPTables sets the stack's iptables to the default tables, which
+// allow and do not modify all traffic.
+func (s *Stack) FillDefaultIPTables() error {
+	return netfilter.FillDefaultIPTables(s.Stack)
+}
diff --git a/pkg/sentry/socket/hostinet/socket.go b/pkg/sentry/socket/hostinet/socket.go
index 7f69406b7..618ea42c7 100644
--- a/pkg/sentry/socket/hostinet/socket.go
+++ b/pkg/sentry/socket/hostinet/socket.go
@@ -272,7 +272,7 @@ func (s *socketOperations) Shutdown(t *kernel.Task, how int) *syserr.Error {
 }
 
 // GetSockOpt implements socket.Socket.GetSockOpt.
-func (s *socketOperations) GetSockOpt(t *kernel.Task, level int, name int, outLen int) (interface{}, *syserr.Error) {
+func (s *socketOperations) GetSockOpt(t *kernel.Task, level int, name int, outPtr usermem.Addr, outLen int) (interface{}, *syserr.Error) {
 	if outLen < 0 {
 		return nil, syserr.ErrInvalidArgument
 	}
diff --git a/pkg/sentry/socket/netfilter/BUILD b/pkg/sentry/socket/netfilter/BUILD
new file mode 100644
index 000000000..3021f83e7
--- /dev/null
+++ b/pkg/sentry/socket/netfilter/BUILD
@@ -0,0 +1,23 @@
+package(licenses = ["notice"])
+
+load("//tools/go_stateify:defs.bzl", "go_library")
+
+go_library(
+    name = "netfilter",
+    srcs = [
+        "netfilter.go",
+    ],
+    importpath = "gvisor.dev/gvisor/pkg/sentry/socket/netfilter",
+    # This target depends on netstack and should only be used by epsocket,
+    # which is allowed to depend on netstack.
+    visibility = ["//pkg/sentry:internal"],
+    deps = [
+        "//pkg/abi/linux",
+        "//pkg/sentry/kernel",
+        "//pkg/sentry/usermem",
+        "//pkg/syserr",
+        "//pkg/tcpip",
+        "//pkg/tcpip/iptables",
+        "//pkg/tcpip/stack",
+    ],
+)
diff --git a/pkg/sentry/socket/netfilter/netfilter.go b/pkg/sentry/socket/netfilter/netfilter.go
new file mode 100644
index 000000000..efdb42903
--- /dev/null
+++ b/pkg/sentry/socket/netfilter/netfilter.go
@@ -0,0 +1,46 @@
+// 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 netfilter helps the sentry interact with netstack's netfilter
+// capabilities.
+package netfilter
+
+import (
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/syserr"
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/iptables"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
+)
+
+// GetInfo returns information about iptables.
+func GetInfo(t *kernel.Task, ep tcpip.Endpoint, outPtr usermem.Addr) (linux.IPTGetinfo, *syserr.Error) {
+	// TODO(b/129292233): Implement.
+	return linux.IPTGetinfo{}, syserr.ErrInvalidArgument
+}
+
+// GetEntries returns netstack's iptables rules encoded for the iptables tool.
+func GetEntries(t *kernel.Task, ep tcpip.Endpoint, outPtr usermem.Addr, outLen int) (linux.KernelIPTGetEntries, *syserr.Error) {
+	// TODO(b/129292233): Implement.
+	return linux.KernelIPTGetEntries{}, syserr.ErrInvalidArgument
+}
+
+// FillDefaultIPTables sets stack's IPTables to the default tables and
+// populates them with metadata.
+func FillDefaultIPTables(stack *stack.Stack) error {
+	stack.SetIPTables(iptables.DefaultTables())
+	return nil
+}
diff --git a/pkg/sentry/socket/netlink/socket.go b/pkg/sentry/socket/netlink/socket.go
index f3d6c1e9b..81c488b29 100644
--- a/pkg/sentry/socket/netlink/socket.go
+++ b/pkg/sentry/socket/netlink/socket.go
@@ -289,7 +289,7 @@ func (s *Socket) Shutdown(t *kernel.Task, how int) *syserr.Error {
 }
 
 // GetSockOpt implements socket.Socket.GetSockOpt.
-func (s *Socket) GetSockOpt(t *kernel.Task, level int, name int, outLen int) (interface{}, *syserr.Error) {
+func (s *Socket) GetSockOpt(t *kernel.Task, level int, name int, outPtr usermem.Addr, outLen int) (interface{}, *syserr.Error) {
 	switch level {
 	case linux.SOL_SOCKET:
 		switch name {
diff --git a/pkg/sentry/socket/rpcinet/socket.go b/pkg/sentry/socket/rpcinet/socket.go
index ccaaddbfc..0e58819bc 100644
--- a/pkg/sentry/socket/rpcinet/socket.go
+++ b/pkg/sentry/socket/rpcinet/socket.go
@@ -395,7 +395,7 @@ func (s *socketOperations) Shutdown(t *kernel.Task, how int) *syserr.Error {
 }
 
 // GetSockOpt implements socket.Socket.GetSockOpt.
-func (s *socketOperations) GetSockOpt(t *kernel.Task, level int, name int, outLen int) (interface{}, *syserr.Error) {
+func (s *socketOperations) GetSockOpt(t *kernel.Task, level int, name int, outPtr usermem.Addr, outLen int) (interface{}, *syserr.Error) {
 	// SO_RCVTIMEO and SO_SNDTIMEO are special because blocking is performed
 	// within the sentry.
 	if level == linux.SOL_SOCKET && name == linux.SO_RCVTIMEO {
diff --git a/pkg/sentry/socket/socket.go b/pkg/sentry/socket/socket.go
index 0efa58a58..30f0a3167 100644
--- a/pkg/sentry/socket/socket.go
+++ b/pkg/sentry/socket/socket.go
@@ -64,7 +64,7 @@ type Socket interface {
 	Shutdown(t *kernel.Task, how int) *syserr.Error
 
 	// GetSockOpt implements the getsockopt(2) linux syscall.
-	GetSockOpt(t *kernel.Task, level int, name int, outLen int) (interface{}, *syserr.Error)
+	GetSockOpt(t *kernel.Task, level int, name int, outPtr usermem.Addr, outLen int) (interface{}, *syserr.Error)
 
 	// SetSockOpt implements the setsockopt(2) linux syscall.
 	SetSockOpt(t *kernel.Task, level int, name int, opt []byte) *syserr.Error
diff --git a/pkg/sentry/socket/unix/unix.go b/pkg/sentry/socket/unix/unix.go
index eb262ecaf..6b1f8679c 100644
--- a/pkg/sentry/socket/unix/unix.go
+++ b/pkg/sentry/socket/unix/unix.go
@@ -166,7 +166,7 @@ func (s *SocketOperations) Ioctl(ctx context.Context, _ *fs.File, io usermem.IO,
 
 // GetSockOpt implements the linux syscall getsockopt(2) for sockets backed by
 // a transport.Endpoint.
-func (s *SocketOperations) GetSockOpt(t *kernel.Task, level, name, outLen int) (interface{}, *syserr.Error) {
+func (s *SocketOperations) GetSockOpt(t *kernel.Task, level, name int, outPtr usermem.Addr, outLen int) (interface{}, *syserr.Error) {
 	return epsocket.GetSockOpt(t, s, s.ep, linux.AF_UNIX, s.ep.Type(), level, name, outLen)
 }
 
diff --git a/pkg/sentry/syscalls/linux/sys_socket.go b/pkg/sentry/syscalls/linux/sys_socket.go
index fa568a660..3bac4d90d 100644
--- a/pkg/sentry/syscalls/linux/sys_socket.go
+++ b/pkg/sentry/syscalls/linux/sys_socket.go
@@ -460,7 +460,7 @@ func GetSockOpt(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy
 	}
 
 	// Call syscall implementation then copy both value and value len out.
-	v, e := getSockOpt(t, s, int(level), int(name), int(optLen))
+	v, e := getSockOpt(t, s, int(level), int(name), optValAddr, int(optLen))
 	if e != nil {
 		return 0, nil, e.ToError()
 	}
@@ -483,7 +483,7 @@ func GetSockOpt(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy
 
 // getSockOpt tries to handle common socket options, or dispatches to a specific
 // socket implementation.
-func getSockOpt(t *kernel.Task, s socket.Socket, level, name, len int) (interface{}, *syserr.Error) {
+func getSockOpt(t *kernel.Task, s socket.Socket, level, name int, optValAddr usermem.Addr, len int) (interface{}, *syserr.Error) {
 	if level == linux.SOL_SOCKET {
 		switch name {
 		case linux.SO_TYPE, linux.SO_DOMAIN, linux.SO_PROTOCOL:
@@ -505,7 +505,7 @@ func getSockOpt(t *kernel.Task, s socket.Socket, level, name, len int) (interfac
 		}
 	}
 
-	return s.GetSockOpt(t, level, name, len)
+	return s.GetSockOpt(t, level, name, optValAddr, len)
 }
 
 // SetSockOpt implements the linux syscall setsockopt(2).