internal: move shim and init into app

This structure makes more sense, as both processes are part of an app's lifecycle.

Signed-off-by: Ophestra <cat@gensokyo.uk>

1 files changed, 0 insertions, 154 deletions

diff --git a/internal/priv/shim/main.go b/internal/priv/shim/main.go
deleted file mode 100644
index 7baf5330..00000000
--- a/internal/priv/shim/main.go
+++ /dev/null
@@ -1,154 +0,0 @@
-package shim
-
-import (
-	"context"
-	"errors"
-	"os"
-	"os/exec"
-	"os/signal"
-	"path"
-	"strconv"
-	"syscall"
-
-	"git.gensokyo.uk/security/fortify/fst"
-	"git.gensokyo.uk/security/fortify/helper"
-	"git.gensokyo.uk/security/fortify/helper/proc"
-	"git.gensokyo.uk/security/fortify/helper/seccomp"
-	"git.gensokyo.uk/security/fortify/internal"
-	"git.gensokyo.uk/security/fortify/internal/fmsg"
-	init0 "git.gensokyo.uk/security/fortify/internal/priv/init"
-)
-
-// everything beyond this point runs as unconstrained target user
-// proceed with caution!
-
-func Main() {
-	// sharing stdout with fortify
-	// USE WITH CAUTION
-	fmsg.SetPrefix("shim")
-
-	// setting this prevents ptrace
-	if err := internal.PR_SET_DUMPABLE__SUID_DUMP_DISABLE(); err != nil {
-		fmsg.Fatalf("cannot set SUID_DUMP_DISABLE: %s", err)
-		panic("unreachable")
-	}
-
-	// receive setup payload
-	var (
-		payload    Payload
-		closeSetup func() error
-	)
-	if f, err := proc.Receive(Env, &payload); err != nil {
-		if errors.Is(err, proc.ErrInvalid) {
-			fmsg.Fatal("invalid config descriptor")
-		}
-		if errors.Is(err, proc.ErrNotSet) {
-			fmsg.Fatal("FORTIFY_SHIM not set")
-		}
-
-		fmsg.Fatalf("cannot decode shim setup payload: %v", err)
-		panic("unreachable")
-	} else {
-		fmsg.SetVerbose(payload.Verbose)
-		closeSetup = f
-	}
-
-	if payload.Bwrap == nil {
-		fmsg.Fatal("bwrap config not supplied")
-	}
-
-	// restore bwrap sync fd
-	var syncFd *os.File
-	if payload.Sync != nil {
-		syncFd = os.NewFile(*payload.Sync, "sync")
-	}
-
-	// close setup socket
-	if err := closeSetup(); err != nil {
-		fmsg.Println("cannot close setup pipe:", err)
-		// not fatal
-	}
-
-	// ensure home directory as target user
-	if s, err := os.Stat(payload.Home); err != nil {
-		if os.IsNotExist(err) {
-			if err = os.Mkdir(payload.Home, 0700); err != nil {
-				fmsg.Fatalf("cannot create home directory: %v", err)
-			}
-		} else {
-			fmsg.Fatalf("cannot access home directory: %v", err)
-		}
-
-		// home directory is created, proceed
-	} else if !s.IsDir() {
-		fmsg.Fatalf("data path %q is not a directory", payload.Home)
-	}
-
-	var ic init0.Payload
-
-	// resolve argv0
-	ic.Argv = payload.Argv
-	if len(ic.Argv) > 0 {
-		// looked up from $PATH by parent
-		ic.Argv0 = payload.Exec[1]
-	} else {
-		// no argv, look up shell instead
-		var ok bool
-		if payload.Bwrap.SetEnv == nil {
-			fmsg.Fatal("no command was specified and environment is unset")
-		}
-		if ic.Argv0, ok = payload.Bwrap.SetEnv["SHELL"]; !ok {
-			fmsg.Fatal("no command was specified and $SHELL was unset")
-		}
-
-		ic.Argv = []string{ic.Argv0}
-	}
-
-	conf := payload.Bwrap
-
-	var extraFiles []*os.File
-
-	// serve setup payload
-	if fd, encoder, err := proc.Setup(&extraFiles); err != nil {
-		fmsg.Fatalf("cannot pipe: %v", err)
-	} else {
-		conf.SetEnv[init0.Env] = strconv.Itoa(fd)
-		go func() {
-			fmsg.VPrintln("transmitting config to init")
-			if err = encoder.Encode(&ic); err != nil {
-				fmsg.Fatalf("cannot transmit init config: %v", err)
-			}
-		}()
-	}
-
-	helper.BubblewrapName = payload.Exec[0] // resolved bwrap path by parent
-	if fmsg.Verbose() {
-		seccomp.CPrintln = fmsg.Println
-	}
-	if b, err := helper.NewBwrap(
-		conf, path.Join(fst.Tmp, "sbin/init"),
-		nil, func(int, int) []string { return make([]string, 0) },
-		extraFiles,
-		syncFd,
-	); err != nil {
-		fmsg.Fatalf("malformed sandbox config: %v", err)
-	} else {
-		b.Stdin(os.Stdin).Stdout(os.Stdout).Stderr(os.Stderr)
-		ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
-		defer stop() // unreachable
-
-		// run and pass through exit code
-		if err = b.Start(ctx, false); err != nil {
-			fmsg.Fatalf("cannot start target process: %v", err)
-		} else if err = b.Wait(); err != nil {
-			var exitError *exec.ExitError
-			if !errors.As(err, &exitError) {
-				fmsg.Println("wait:", err)
-				fmsg.Exit(127)
-				panic("unreachable")
-			}
-			fmsg.Exit(exitError.ExitCode())
-			panic("unreachable")
-		}
-	}
-}