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-rw-r--r--pkg/sentry/fs/proc/BUILD1
-rw-r--r--pkg/sentry/fs/proc/sys_net.go105
-rw-r--r--pkg/sentry/fs/proc/sys_net_state.go21
-rw-r--r--pkg/sentry/fs/proc/sys_net_test.go68
-rw-r--r--pkg/sentry/inet/BUILD5
-rw-r--r--pkg/sentry/inet/inet.go8
-rw-r--r--pkg/sentry/inet/test_stack.go16
-rw-r--r--pkg/sentry/socket/hostinet/BUILD3
-rw-r--r--pkg/sentry/socket/hostinet/stack.go30
-rw-r--r--pkg/sentry/socket/netstack/stack.go24
-rw-r--r--pkg/sentry/socket/rpcinet/stack.go11
11 files changed, 290 insertions, 2 deletions
diff --git a/pkg/sentry/fs/proc/BUILD b/pkg/sentry/fs/proc/BUILD
index 75cbb0622..f21e2a65c 100644
--- a/pkg/sentry/fs/proc/BUILD
+++ b/pkg/sentry/fs/proc/BUILD
@@ -53,6 +53,7 @@ go_library(
"//pkg/sentry/usermem",
"//pkg/syserror",
"//pkg/tcpip/header",
+ "//pkg/tcpip/network/ipv4",
"//pkg/waiter",
],
)
diff --git a/pkg/sentry/fs/proc/sys_net.go b/pkg/sentry/fs/proc/sys_net.go
index f3b63dfc2..794723d9c 100644
--- a/pkg/sentry/fs/proc/sys_net.go
+++ b/pkg/sentry/fs/proc/sys_net.go
@@ -27,6 +27,7 @@ import (
"gvisor.dev/gvisor/pkg/sentry/fs/ramfs"
"gvisor.dev/gvisor/pkg/sentry/inet"
"gvisor.dev/gvisor/pkg/sentry/usermem"
+ "gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
"gvisor.dev/gvisor/pkg/waiter"
)
@@ -280,11 +281,115 @@ func (p *proc) newSysNetCore(ctx context.Context, msrc *fs.MountSource, s inet.S
return newProcInode(ctx, d, msrc, fs.SpecialDirectory, nil)
}
+// ipForwarding implements fs.InodeOperations.
+//
+// ipForwarding is used to enable/disable packet forwarding of netstack.
+//
+// +stateify savable
+type ipForwarding struct {
+ stack inet.Stack `state:".(ipForwardingState)"`
+ fsutil.SimpleFileInode
+}
+
+// ipForwardingState is used to stores a state of netstack
+// for packet forwarding because netstack itself is stateless.
+//
+// +stateify savable
+type ipForwardingState struct {
+ stack inet.Stack `state:"wait"`
+
+ // enabled stores packet forwarding settings during save, and sets it back
+ // in netstack in restore. We must save/restore this here, since
+ // netstack itself is stateless.
+ enabled bool
+}
+
+func newIPForwardingInode(ctx context.Context, msrc *fs.MountSource, s inet.Stack) *fs.Inode {
+ ipf := &ipForwarding{
+ SimpleFileInode: *fsutil.NewSimpleFileInode(ctx, fs.RootOwner, fs.FilePermsFromMode(0444), 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, ipf, msrc, sattr)
+}
+
+// +stateify savable
+type ipForwardingFile 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"`
+
+ stack inet.Stack `state:"wait"`
+}
+
+// GetFile implements fs.InodeOperations.GetFile.
+func (ipf *ipForwarding) 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, &ipForwardingFile{
+ stack: ipf.stack,
+ }), nil
+}
+
+// Read implements fs.FileOperations.Read.
+func (f *ipForwardingFile) Read(ctx context.Context, _ *fs.File, dst usermem.IOSequence, offset int64) (int64, error) {
+ if offset != 0 {
+ return 0, io.EOF
+ }
+
+ val := "0\n"
+ if f.stack.Forwarding(ipv4.ProtocolNumber) {
+ // Technically, this is not quite compatible with Linux. Linux
+ // stores these as an integer, so if you write "2" into
+ // ip_forward, you should get 2 back.
+ val = "1\n"
+ }
+
+ n, err := dst.CopyOut(ctx, []byte(val))
+ return int64(n), err
+}
+
+// Write implements fs.FileOperations.Write.
+//
+// Offset is ignored, multiple writes are not supported.
+func (f *ipForwardingFile) Write(ctx context.Context, _ *fs.File, src usermem.IOSequence, offset int64) (int64, error) {
+ if src.NumBytes() == 0 {
+ return 0, nil
+ }
+
+ // Only consider size of one memory page for input.
+ 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 n, err
+ }
+
+ enabled := v != 0
+ return n, f.stack.SetForwarding(ipv4.ProtocolNumber, enabled)
+}
+
func (p *proc) newSysNetIPv4Dir(ctx context.Context, msrc *fs.MountSource, s inet.Stack) *fs.Inode {
contents := map[string]*fs.Inode{
// Add tcp_sack.
"tcp_sack": newTCPSackInode(ctx, msrc, s),
+ // Add ip_forward.
+ "ip_forward": newIPForwardingInode(ctx, msrc, s),
+
// The following files are simple stubs until they are
// implemented in netstack, most of these files are
// configuration related. We use the value closest to the
diff --git a/pkg/sentry/fs/proc/sys_net_state.go b/pkg/sentry/fs/proc/sys_net_state.go
index 6eba709c6..02e43297f 100644
--- a/pkg/sentry/fs/proc/sys_net_state.go
+++ b/pkg/sentry/fs/proc/sys_net_state.go
@@ -14,7 +14,10 @@
package proc
-import "fmt"
+import (
+ "fmt"
+ "gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
+)
// beforeSave is invoked by stateify.
func (t *tcpMemInode) beforeSave() {
@@ -40,3 +43,19 @@ func (s *tcpSack) afterLoad() {
}
}
}
+
+// saveStack is invoked by stateify.
+func (ipf *ipForwarding) saveStack() ipForwardingState {
+ return ipForwardingState{
+ ipf.stack,
+ ipf.stack.Forwarding(ipv4.ProtocolNumber),
+ }
+}
+
+// loadStack is invoked by stateify.
+func (ipf *ipForwarding) loadStack(s ipForwardingState) {
+ ipf.stack = s.stack
+ if err := ipf.stack.SetForwarding(ipv4.ProtocolNumber, s.enabled); err != nil {
+ panic(fmt.Sprintf("failed to set previous IPv4 forwarding configuration [%v]: %v", s.enabled, err))
+ }
+}
diff --git a/pkg/sentry/fs/proc/sys_net_test.go b/pkg/sentry/fs/proc/sys_net_test.go
index 6abae7a60..6e51dfbb7 100644
--- a/pkg/sentry/fs/proc/sys_net_test.go
+++ b/pkg/sentry/fs/proc/sys_net_test.go
@@ -123,3 +123,71 @@ func TestConfigureRecvBufferSize(t *testing.T) {
}
}
}
+
+func TestConfigureIPForwarding(t *testing.T) {
+ ctx := context.Background()
+ s := inet.NewTestStack()
+
+ var cases = []struct {
+ comment string
+ initial bool
+ str string
+ final bool
+ }{
+ {
+ comment: `Forwarding is disabled; write 1 and enable forwarding`,
+ initial: false,
+ str: "1",
+ final: true,
+ },
+ {
+ comment: `Forwarding is disabled; write 0 and disable forwarding`,
+ initial: false,
+ str: "0",
+ final: false,
+ },
+ {
+ comment: `Forwarding is enabled; write 1 and enable forwarding`,
+ initial: true,
+ str: "1",
+ final: true,
+ },
+ {
+ comment: `Forwarding is enabled; write 0 and disable forwarding`,
+ initial: true,
+ str: "0",
+ final: false,
+ },
+ {
+ comment: `Forwarding is disabled; write 2404 and enable forwarding`,
+ initial: false,
+ str: "2404",
+ final: true,
+ },
+ {
+ comment: `Forwarding is enabled; write 2404 and enable forwarding`,
+ initial: true,
+ str: "2404",
+ final: true,
+ },
+ }
+ for _, c := range cases {
+ t.Run(c.comment, func(t *testing.T) {
+ s.IPForwarding = c.initial
+
+ file := &ipForwardingFile{stack: s}
+
+ // Write the values.
+ src := usermem.BytesIOSequence([]byte(c.str))
+ if n, err := file.Write(ctx, nil, src, 0); n != int64(len(c.str)) || err != nil {
+ t.Errorf("file.Write(ctx, nil, %v, 0) = (%d, %v); wanted (%d, nil)", c.str, n, err, len(c.str))
+ }
+
+ // Read the values from the stack and check them.
+ if s.IPForwarding != c.final {
+ t.Errorf("s.IPForwarding = %v; wanted %v", s.IPForwarding, c.final)
+ }
+
+ })
+ }
+}
diff --git a/pkg/sentry/inet/BUILD b/pkg/sentry/inet/BUILD
index d5284f0d9..99481e05e 100644
--- a/pkg/sentry/inet/BUILD
+++ b/pkg/sentry/inet/BUILD
@@ -13,5 +13,8 @@ go_library(
"test_stack.go",
],
importpath = "gvisor.dev/gvisor/pkg/sentry/inet",
- deps = ["//pkg/sentry/context"],
+ deps = [
+ "//pkg/sentry/context",
+ "//pkg/tcpip",
+ ],
)
diff --git a/pkg/sentry/inet/inet.go b/pkg/sentry/inet/inet.go
index bc6cb1095..6217100b2 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 represents a TCP/IP stack.
type Stack interface {
// Interfaces returns all network interfaces as a mapping from interface
@@ -58,6 +60,12 @@ type Stack interface {
// Resume restarts the network stack after restore.
Resume()
+
+ // Forwarding returns if packet forwarding between NICs is enabled.
+ Forwarding(protocol tcpip.NetworkProtocolNumber) bool
+
+ // SetForwarding enables or disables packet forwarding between NICs.
+ SetForwarding(protocol tcpip.NetworkProtocolNumber, enable bool) error
}
// Interface contains information about a network interface.
diff --git a/pkg/sentry/inet/test_stack.go b/pkg/sentry/inet/test_stack.go
index b9eed7c3a..c6907cfcb 100644
--- a/pkg/sentry/inet/test_stack.go
+++ b/pkg/sentry/inet/test_stack.go
@@ -14,6 +14,10 @@
package inet
+import (
+ "gvisor.dev/gvisor/pkg/tcpip"
+)
+
// TestStack is a dummy implementation of Stack for tests.
type TestStack struct {
InterfacesMap map[int32]Interface
@@ -23,6 +27,7 @@ type TestStack struct {
TCPRecvBufSize TCPBufferSize
TCPSendBufSize TCPBufferSize
TCPSACKFlag bool
+ IPForwarding bool
}
// NewTestStack returns a TestStack with no network interfaces. The value of
@@ -96,3 +101,14 @@ func (s *TestStack) RouteTable() []Route {
// Resume implements Stack.Resume.
func (s *TestStack) Resume() {
}
+
+// Forwarding implements inet.Stack.Forwarding.
+func (s *TestStack) Forwarding(protocol tcpip.NetworkProtocolNumber) bool {
+ return s.IPForwarding
+}
+
+// SetForwarding implements inet.Stack.SetForwarding.
+func (s *TestStack) SetForwarding(protocol tcpip.NetworkProtocolNumber, enable bool) error {
+ s.IPForwarding = enable
+ return nil
+}
diff --git a/pkg/sentry/socket/hostinet/BUILD b/pkg/sentry/socket/hostinet/BUILD
index 4d174dda4..c1b20eaf8 100644
--- a/pkg/sentry/socket/hostinet/BUILD
+++ b/pkg/sentry/socket/hostinet/BUILD
@@ -32,6 +32,9 @@ go_library(
"//pkg/sentry/usermem",
"//pkg/syserr",
"//pkg/syserror",
+ "//pkg/tcpip",
+ "//pkg/tcpip/network/ipv4",
+ "//pkg/tcpip/network/ipv6",
"//pkg/waiter",
],
)
diff --git a/pkg/sentry/socket/hostinet/stack.go b/pkg/sentry/socket/hostinet/stack.go
index d4387f5d4..4b460d30e 100644
--- a/pkg/sentry/socket/hostinet/stack.go
+++ b/pkg/sentry/socket/hostinet/stack.go
@@ -31,6 +31,9 @@ import (
"gvisor.dev/gvisor/pkg/sentry/usermem"
"gvisor.dev/gvisor/pkg/syserr"
"gvisor.dev/gvisor/pkg/syserror"
+ "gvisor.dev/gvisor/pkg/tcpip"
+ "gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
+ "gvisor.dev/gvisor/pkg/tcpip/network/ipv6"
)
var defaultRecvBufSize = inet.TCPBufferSize{
@@ -57,6 +60,8 @@ type Stack struct {
tcpSACKEnabled bool
netDevFile *os.File
netSNMPFile *os.File
+ ipv4Forwarding bool
+ ipv6Forwarding bool
}
// NewStack returns an empty Stack containing no configuration.
@@ -116,6 +121,13 @@ func (s *Stack) Configure() error {
s.netSNMPFile = f
}
+ s.ipv4Forwarding = false
+ if ipForwarding, err := ioutil.ReadFile("/proc/sys/net/ipv4/ip_forward"); err == nil {
+ s.ipv4Forwarding = strings.TrimSpace(string(ipForwarding)) != "0"
+ } else {
+ log.Warningf("Failed to read if IPv4 forwarding is enabled, setting to false")
+ }
+
return nil
}
@@ -442,3 +454,21 @@ func (s *Stack) RouteTable() []inet.Route {
// Resume implements inet.Stack.Resume.
func (s *Stack) Resume() {}
+
+// Forwarding implements inet.Stack.Forwarding.
+func (s *Stack) Forwarding(protocol tcpip.NetworkProtocolNumber) bool {
+ switch protocol {
+ case ipv4.ProtocolNumber:
+ return s.ipv4Forwarding
+ case ipv6.ProtocolNumber:
+ return s.ipv6Forwarding
+ default:
+ log.Warningf("Forwarding(%v) failed: unsupported protocol", protocol)
+ return false
+ }
+}
+
+// SetForwarding implements inet.Stack.SetForwarding.
+func (s *Stack) SetForwarding(protocol tcpip.NetworkProtocolNumber, enable bool) error {
+ return syserror.EACCES
+}
diff --git a/pkg/sentry/socket/netstack/stack.go b/pkg/sentry/socket/netstack/stack.go
index d5db8c17c..d0102cfa3 100644
--- a/pkg/sentry/socket/netstack/stack.go
+++ b/pkg/sentry/socket/netstack/stack.go
@@ -20,6 +20,7 @@ import (
"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"
@@ -291,3 +292,26 @@ func (s *Stack) FillDefaultIPTables() {
func (s *Stack) Resume() {
s.Stack.Resume()
}
+
+// Forwarding implements inet.Stack.Forwarding.
+func (s *Stack) Forwarding(protocol tcpip.NetworkProtocolNumber) bool {
+ switch protocol {
+ case ipv4.ProtocolNumber, ipv6.ProtocolNumber:
+ return s.Stack.Forwarding(protocol)
+ default:
+ log.Warningf("Forwarding(%v) failed: unsupported protocol", protocol)
+ return false
+ }
+}
+
+// SetForwarding implements inet.Stack.SetForwarding.
+func (s *Stack) SetForwarding(protocol tcpip.NetworkProtocolNumber, enable bool) error {
+ switch protocol {
+ case ipv4.ProtocolNumber, ipv6.ProtocolNumber:
+ s.Stack.SetForwarding(protocol, enable)
+ default:
+ log.Warningf("SetForwarding(%v) failed: unsupported protocol", protocol)
+ return syserr.ErrProtocolNotSupported.ToError()
+ }
+ return nil
+}
diff --git a/pkg/sentry/socket/rpcinet/stack.go b/pkg/sentry/socket/rpcinet/stack.go
index 5dcb6b455..f5441b826 100644
--- a/pkg/sentry/socket/rpcinet/stack.go
+++ b/pkg/sentry/socket/rpcinet/stack.go
@@ -23,6 +23,7 @@ import (
"gvisor.dev/gvisor/pkg/sentry/socket/rpcinet/conn"
"gvisor.dev/gvisor/pkg/sentry/socket/rpcinet/notifier"
"gvisor.dev/gvisor/pkg/syserr"
+ "gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/unet"
)
@@ -165,3 +166,13 @@ func (s *Stack) RouteTable() []inet.Route {
// Resume implements inet.Stack.Resume.
func (s *Stack) Resume() {}
+
+// Forwarding implements inet.Stack.Forwarding.
+func (s *Stack) Forwarding(protocol tcpip.NetworkProtocolNumber) bool {
+ panic("rpcinet handles procfs directly this method should not be called")
+}
+
+// SetForwarding implements inet.Stack.SetForwarding.
+func (s *Stack) SetForwarding(protocol tcpip.NetworkProtocolNumber, enable bool) error {
+ panic("rpcinet handles procfs directly this method should not be called")
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-06 07:36:35 +0000