proc/priv/shim: merge shim into main program

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

1 files changed, 0 insertions, 165 deletions

diff --git a/cmd/fshim/main.go b/cmd/fshim/main.go
deleted file mode 100644
index 5aece38f..00000000
--- a/cmd/fshim/main.go
+++ /dev/null
@@ -1,165 +0,0 @@
-package main
-
-import (
-	"errors"
-	"os"
-	"path"
-	"strconv"
-	"syscall"
-
-	init0 "git.gensokyo.uk/security/fortify/cmd/finit/ipc"
-	shim "git.gensokyo.uk/security/fortify/cmd/fshim/ipc"
-	"git.gensokyo.uk/security/fortify/fst"
-	"git.gensokyo.uk/security/fortify/helper"
-	"git.gensokyo.uk/security/fortify/internal"
-	"git.gensokyo.uk/security/fortify/internal/fmsg"
-	"git.gensokyo.uk/security/fortify/internal/proc"
-)
-
-// 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")
-	}
-
-	// re-exec
-	if len(os.Args) > 0 && (os.Args[0] != "fshim" || len(os.Args) != 1) && path.IsAbs(os.Args[0]) {
-		if err := syscall.Exec(os.Args[0], []string{"fshim"}, os.Environ()); err != nil {
-			fmsg.Println("cannot re-exec self:", err)
-			// continue anyway
-		}
-	}
-
-	// check path to finit
-	var finitPath string
-	if p, ok := internal.Path(internal.Finit); !ok {
-		fmsg.Fatal("invalid finit path, this copy of fshim is not compiled correctly")
-	} else {
-		finitPath = p
-	}
-
-	// receive setup payload
-	var (
-		payload    shim.Payload
-		closeSetup func() error
-	)
-	if f, err := proc.Receive(shim.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
-	if payload.Sync != nil {
-		payload.Bwrap.SetSync(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)
-			}
-		}()
-	}
-
-	// bind finit inside sandbox
-	finitInnerPath := path.Join(fst.Tmp, "sbin", "init")
-	conf.Bind(finitPath, finitInnerPath)
-
-	helper.BubblewrapName = payload.Exec[0] // resolved bwrap path by parent
-	if b, err := helper.NewBwrap(conf, nil, finitInnerPath,
-		func(int, int) []string { return make([]string, 0) }); err != nil {
-		fmsg.Fatalf("malformed sandbox config: %v", err)
-	} else {
-		cmd := b.Unwrap()
-		cmd.Stdin, cmd.Stdout, cmd.Stderr = os.Stdin, os.Stdout, os.Stderr
-		cmd.ExtraFiles = extraFiles
-
-		if fmsg.Verbose() {
-			fmsg.VPrintln("bwrap args:", conf.Args())
-		}
-
-		// run and pass through exit code
-		if err = b.Start(); err != nil {
-			fmsg.Fatalf("cannot start target process: %v", err)
-		} else if err = b.Wait(); err != nil {
-			fmsg.VPrintln("wait:", err)
-		}
-		if b.Unwrap().ProcessState != nil {
-			fmsg.Exit(b.Unwrap().ProcessState.ExitCode())
-		} else {
-			fmsg.Exit(127)
-		}
-	}
-}