fortify/main.go

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package main
import (
"errors"
"flag"
"fmt"
"io/fs"
"os"
"path"
"strconv"
"syscall"
"git.ophivana.moe/cat/fortify/internal/acl"
"git.ophivana.moe/cat/fortify/internal/app"
"git.ophivana.moe/cat/fortify/internal/state"
"git.ophivana.moe/cat/fortify/internal/system"
"git.ophivana.moe/cat/fortify/internal/util"
"git.ophivana.moe/cat/fortify/internal/xcb"
)
var (
Version = "impure"
a *app.App
)
func tryVersion() {
if printVersion {
fmt.Println(Version)
os.Exit(0)
}
}
const (
term = "TERM"
display = "DISPLAY"
// https://manpages.debian.org/experimental/libwayland-doc/wl_display_connect.3.en.html
waylandDisplay = "WAYLAND_DISPLAY"
)
func main() {
flag.Parse()
// launcher payload early exit
app.Early(printVersion)
// version/license command early exit
tryVersion()
tryLicense()
system.Retrieve(flagVerbose)
a = app.New(userName, flag.Args())
state.Set(*a.User, a.Command(), a.UID())
// ensure RunDir (e.g. `/run/user/%d/fortify`)
if err := os.Mkdir(system.V.RunDir, 0700); err != nil && !errors.Is(err, fs.ErrExist) {
state.Fatal("Error creating runtime directory:", err)
}
// state query command early exit
state.Early()
// ensure Share (e.g. `/tmp/fortify.%d`)
// acl is unnecessary as this directory is world executable
if err := os.Mkdir(system.V.Share, 0701); err != nil && !errors.Is(err, fs.ErrExist) {
state.Fatal("Error creating shared directory:", err)
}
// warn about target user home directory ownership
if stat, err := os.Stat(a.HomeDir); err != nil {
if system.V.Verbose {
switch {
case errors.Is(err, fs.ErrPermission):
fmt.Printf("User %s home directory %s is not accessible", a.Username, a.HomeDir)
case errors.Is(err, fs.ErrNotExist):
fmt.Printf("User %s home directory %s does not exist", a.Username, a.HomeDir)
default:
fmt.Printf("Error stat user %s home directory %s: %s", a.Username, a.HomeDir, err)
}
}
return
} else {
// FreeBSD: not cross-platform
if u := strconv.Itoa(int(stat.Sys().(*syscall.Stat_t).Uid)); u != a.Uid {
fmt.Printf("User %s home directory %s has incorrect ownership (expected UID %s, found %s)", a.Username, a.HomeDir, a.Uid, u)
}
}
// ensure runtime directory ACL (e.g. `/run/user/%d`)
if s, err := os.Stat(system.V.Runtime); err != nil {
if errors.Is(err, fs.ErrNotExist) {
state.Fatal("Runtime directory does not exist")
}
state.Fatal("Error accessing runtime directory:", err)
} else if !s.IsDir() {
state.Fatal(fmt.Sprintf("Path '%s' is not a directory", system.V.Runtime))
} else {
if err = acl.UpdatePerm(system.V.Runtime, a.UID(), acl.Execute); err != nil {
state.Fatal("Error preparing runtime dir:", err)
} else {
state.RegisterRevertPath(system.V.Runtime)
}
if system.V.Verbose {
fmt.Printf("Runtime data dir '%s' configured\n", system.V.Runtime)
}
}
// ensure Wayland socket ACL (e.g. `/run/user/%d/wayland-%d`)
if w, ok := os.LookupEnv(waylandDisplay); !ok {
if system.V.Verbose {
fmt.Println("Wayland: WAYLAND_DISPLAY not set, skipping")
}
} else {
// add environment variable for new process
wp := path.Join(system.V.Runtime, w)
a.AppendEnv(waylandDisplay, wp)
if err := acl.UpdatePerm(wp, a.UID(), acl.Read, acl.Write, acl.Execute); err != nil {
state.Fatal(fmt.Sprintf("Error preparing Wayland '%s':", w), err)
} else {
state.RegisterRevertPath(wp)
}
if system.V.Verbose {
fmt.Printf("Wayland socket '%s' configured\n", w)
}
}
// discovery X11 and grant user permission via the `ChangeHosts` command
if d, ok := os.LookupEnv(display); !ok {
if system.V.Verbose {
fmt.Println("X11: DISPLAY not set, skipping")
}
} else {
// add environment variable for new process
a.AppendEnv(display, d)
if system.V.Verbose {
fmt.Printf("X11: Adding XHost entry SI:localuser:%s to display '%s'\n", a.Username, d)
}
if err := xcb.ChangeHosts(xcb.HostModeInsert, xcb.FamilyServerInterpreted, "localuser\x00"+a.Username); err != nil {
state.Fatal(fmt.Sprintf("Error adding XHost entry to '%s':", d), err)
} else {
state.XcbActionComplete()
}
}
// ensure PulseAudio directory ACL (e.g. `/run/user/%d/pulse`)
pulse := path.Join(system.V.Runtime, "pulse")
pulseS := path.Join(pulse, "native")
if s, err := os.Stat(pulse); err != nil {
if !errors.Is(err, fs.ErrNotExist) {
state.Fatal("Error accessing PulseAudio directory:", err)
}
if mustPulse {
state.Fatal("PulseAudio is unavailable")
}
if system.V.Verbose {
fmt.Printf("PulseAudio dir '%s' not found, skipping\n", pulse)
}
} else {
// add environment variable for new process
a.AppendEnv(util.PulseServer, "unix:"+pulseS)
if err = acl.UpdatePerm(pulse, a.UID(), acl.Execute); err != nil {
state.Fatal("Error preparing PulseAudio:", err)
} else {
state.RegisterRevertPath(pulse)
}
// ensure PulseAudio socket permission (e.g. `/run/user/%d/pulse/native`)
if s, err = os.Stat(pulseS); err != nil {
if errors.Is(err, fs.ErrNotExist) {
state.Fatal("PulseAudio directory found but socket does not exist")
}
state.Fatal("Error accessing PulseAudio socket:", err)
} else {
if m := s.Mode(); m&0o006 != 0o006 {
state.Fatal(fmt.Sprintf("Unexpected permissions on '%s':", pulseS), m)
}
}
// Publish current user's pulse-cookie for target user
pulseCookieSource := util.DiscoverPulseCookie()
pulseCookieFinal := path.Join(system.V.Share, "pulse-cookie")
a.AppendEnv(util.PulseCookie, pulseCookieFinal)
if system.V.Verbose {
fmt.Printf("Publishing PulseAudio cookie '%s' to '%s'\n", pulseCookieSource, pulseCookieFinal)
}
if err = util.CopyFile(pulseCookieFinal, pulseCookieSource); err != nil {
state.Fatal("Error copying PulseAudio cookie:", err)
}
if err = acl.UpdatePerm(pulseCookieFinal, a.UID(), acl.Read); err != nil {
state.Fatal("Error publishing PulseAudio cookie:", err)
} else {
state.RegisterRevertPath(pulseCookieFinal)
}
if system.V.Verbose {
fmt.Printf("PulseAudio dir '%s' configured\n", pulse)
}
}
// pass $TERM to launcher
if t, ok := os.LookupEnv(term); ok {
a.AppendEnv(term, t)
}
a.Run()
}