101 lines
2.9 KiB
Go
101 lines
2.9 KiB
Go
package main
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import (
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"net"
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"os"
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"os/signal"
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"syscall"
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"google.golang.org/grpc"
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"google.golang.org/grpc/credentials"
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"golang.org/x/net/context"
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"golang.org/x/sys/unix"
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"github.com/containerd/containerd/reaper"
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"github.com/containerd/containerd/sys"
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runc "github.com/containerd/go-runc"
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"github.com/pkg/errors"
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)
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// setupSignals creates a new signal handler for all signals and sets the shim as a
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// sub-reaper so that the container processes are reparented
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func setupSignals() (chan os.Signal, error) {
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signals := make(chan os.Signal, 2048)
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signal.Notify(signals)
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// make sure runc is setup to use the monitor
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// for waiting on processes
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runc.Monitor = reaper.Default
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// set the shim as the subreaper for all orphaned processes created by the container
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if err := sys.SetSubreaper(1); err != nil {
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return nil, err
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}
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return signals, nil
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}
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// setupRoot sets up the root as the shim is started in its own mount namespace
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func setupRoot() error {
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return unix.Mount("", "/", "", unix.MS_SLAVE|unix.MS_REC, "")
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}
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func newServer() *grpc.Server {
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return grpc.NewServer(grpc.Creds(NewUnixSocketCredentils(0, 0)))
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}
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type unixSocketCredentials struct {
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uid int
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gid int
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serverName string
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}
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func NewUnixSocketCredentils(uid, gid int) credentials.TransportCredentials {
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return &unixSocketCredentials{uid, gid, "locahost"}
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}
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func (u *unixSocketCredentials) ClientHandshake(ctx context.Context, addr string, rawConn net.Conn) (net.Conn, credentials.AuthInfo, error) {
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return nil, nil, errors.New("ClientHandshake is not supported by unixSocketCredentials")
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}
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func (u *unixSocketCredentials) ServerHandshake(c net.Conn) (net.Conn, credentials.AuthInfo, error) {
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uc, ok := c.(*net.UnixConn)
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if !ok {
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return nil, nil, errors.New("unixSocketCredentials only supports unix socket")
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}
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f, err := uc.File()
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if err != nil {
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return nil, nil, errors.Wrap(err, "unixSocketCredentials: failed to retrieve connection underlying fd")
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}
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pcred, err := syscall.GetsockoptUcred(int(f.Fd()), syscall.SOL_SOCKET, syscall.SO_PEERCRED)
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if err != nil {
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return nil, nil, errors.Wrap(err, "unixSocketCredentials: failed to retrieve socket peer credentials")
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}
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if (u.uid != -1 && uint32(u.uid) != pcred.Uid) || (u.gid != -1 && uint32(u.gid) != pcred.Gid) {
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return nil, nil, errors.New("unixSocketCredentials: invalid credentials")
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}
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return c, u, nil
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}
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func (u *unixSocketCredentials) Info() credentials.ProtocolInfo {
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return credentials.ProtocolInfo{
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SecurityProtocol: "unix-socket-peer-creds",
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SecurityVersion: "1.0",
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ServerName: u.serverName,
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}
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}
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func (u *unixSocketCredentials) Clone() credentials.TransportCredentials {
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return &unixSocketCredentials{u.uid, u.gid, u.serverName}
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}
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func (u *unixSocketCredentials) OverrideServerName(serverName string) error {
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u.serverName = serverName
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return nil
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}
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func (u *unixSocketCredentials) AuthType() string {
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return "unix-socket-peer-creds"
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}
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