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Fix mounts (#241)

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Co-authored-by: Dimitris Karakasilis <dimitris@karakasilis.me>
This commit is contained in:
Itxaka 2024-03-15 09:24:54 +01:00 committed by GitHub
parent f25066af47
commit a78e2b7ce7
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GPG Key ID: B5690EEEBB952194
3 changed files with 159 additions and 55 deletions
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2
internal/utils/mounts.go
View File

@ -202,10 +202,12 @@ func MountBasic() {
_ = os.MkdirAll("/proc", 0755)
if !IsMounted("/proc") {
_ = syscall.Mount("proc", "/proc", "proc", syscall.MS_NOSUID|syscall.MS_NODEV|syscall.MS_NOEXEC|syscall.MS_RELATIME, "")
_ = syscall.Mount("", "/proc", "", syscall.MS_SHARED, "")
}
_ = os.MkdirAll("/run", 0755)
if !IsMounted("/run") {
_ = syscall.Mount("tmpfs", "/run", "tmpfs", syscall.MS_NOSUID|syscall.MS_NODEV|syscall.MS_NOEXEC|syscall.MS_RELATIME, "mode=755")
_ = syscall.Mount("", "/run", "", syscall.MS_SHARED, "")
}
}

191
pkg/mount/dag_steps.go
View File

@ -11,7 +11,6 @@ import (
"syscall"
"time"
"github.com/sanity-io/litter"
"golang.org/x/sys/unix"
"github.com/foxboron/go-uefi/efi"
@ -432,17 +431,24 @@ func (s *State) UKIMountBaseSystem(g *herd.Graph) error {
"",
},
{
"/dev",
"devtmpfs",
"devtmpfs",
syscall.MS_NOSUID,
"mode=755",
"/sys",
"",
"",
syscall.MS_SHARED,
"",
},
{
"/tmp",
"tmpfs",
"tmpfs",
syscall.MS_NOSUID | syscall.MS_NODEV,
"/sys/kernel/security",
"securityfs",
"securityfs",
0,
"",
},
{
"/sys/kernel/debug",
"debugfs",
"debugfs",
0,
"",
},
{
@ -452,6 +458,61 @@ func (s *State) UKIMountBaseSystem(g *herd.Graph) error {
syscall.MS_NOSUID | syscall.MS_NODEV | syscall.MS_NOEXEC | syscall.MS_RELATIME,
"",
},
{
"/dev",
"devtmpfs",
"devtmpfs",
syscall.MS_NOSUID,
"mode=755",
},
{
"/dev",
"",
"",
syscall.MS_SHARED,
"",
},
{
"/dev/pts",
"devpts",
"devpts",
syscall.MS_NOSUID | syscall.MS_NOEXEC,
"ptmxmode=000,gid=5,mode=620",
},
{
"/dev/shm",
"tmpfs",
"tmpfs",
0,
"",
},
{
"/tmp",
"tmpfs",
"tmpfs",
syscall.MS_NOSUID | syscall.MS_NODEV,
"",
},
{
"/tmp",
"",
"",
syscall.MS_SHARED,
"",
},
}
for dir, perm := range map[string]os.FileMode{
"/proc": 0o555,
"/dev": 0o777,
"/dev/pts": 0o777,
"/dev/shm": 0o777,
"/sys": 0o555,
} {
e := os.MkdirAll(dir, perm)
if e != nil {
internalUtils.Log.Err(e).Str("dir", dir).Interface("permissions", perm).Msg("Creating dir")
}
}
for _, m := range mounts {
e := os.MkdirAll(m.where, 0755)
@ -788,27 +849,42 @@ func (s *State) UKIBootInitDagStep(g *herd.Graph) error {
herd.WeakDeps,
herd.WithWeakDeps(cnst.OpRemountRootRO, cnst.OpRootfsHook, cnst.OpInitramfsHook, cnst.OpWriteFstab),
herd.WithCallback(func(ctx context.Context) error {
var err error
output, err := internalUtils.CommandWithPath("/usr/lib/systemd/systemd-pcrphase --graceful leave-initrd")
if err != nil {
internalUtils.Log.Err(err).Msg("running systemd-pcrphase")
internalUtils.Log.Debug().Str("out", output).Msg("systemd-pcrphase leave-initrd")
dropToShell()
}
// make s.OverlayDirs shared so their submounts are moved to the new root
// We mount some mounts as overlay and then mount things on top of them
// If they are private, when moving the mount it will end up empty in the new sysroot
// so we make it shared so it propagates correctly with whatever is mounted on it
for _, d := range s.OverlayDirs {
internalUtils.Log.Debug().Str("what", d).Msg("Move overlay")
err := syscall.Mount(d, d, "", syscall.MS_SHARED|syscall.MS_REC, "")
if err != nil {
internalUtils.Log.Err(err).Str("what", d).Msg("mounting overlay as shared")
}
}
// Print dag before exit, otherwise its never printed as we never exit the program
internalUtils.Log.Info().Msg(s.WriteDAG(g))
// Mount a tmpfs under sysroot
err = syscall.Mount("tmpfs", s.path(cnst.UkiSysrootDir), "tmpfs", syscall.MS_NOSUID|syscall.MS_NODEV|syscall.MS_NOEXEC, "")
internalUtils.Log.Debug().Msg("Mounting tmpfs on sysroot")
err = syscall.Mount("tmpfs", s.path(cnst.UkiSysrootDir), "tmpfs", 0, "")
if err != nil {
internalUtils.Log.Err(err).Msg("mounting tmpfs on sysroot")
dropToShell()
}
// Move all the dirs in root FS that are not a mountpoint to the new root via Bind mount
// Move all the dirs in root FS that are not a mountpoint to the new root via cp -R
rootDirs, err := os.ReadDir(s.Rootdir)
if err != nil {
internalUtils.Log.Err(err).Msg("reading rootdir content")
}
mountPoints := []string{}
internalUtils.Log.Debug().Str("s", litter.Sdump(rootDirs)).Msg("Moving root dirs to sysroot")
var mountPoints []string
for _, file := range rootDirs {
if file.Name() == cnst.UkiSysrootDir {
continue
@ -826,25 +902,22 @@ func (s *State) UKIBootInitDagStep(g *herd.Graph) error {
}
// If the directory has the same device as its parent, it's not a mount point.
if fileInfo.Sys().(*syscall.Stat_t).Dev == parentInfo.Sys().(*syscall.Stat_t).Dev {
internalUtils.Log.Debug().Msg(fmt.Sprintf("%s is a simple directory", path))
internalUtils.Log.Debug().Str("what", path).Msg("simple directory")
err = os.MkdirAll(filepath.Join(s.path(cnst.UkiSysrootDir), path), 0755)
if err != nil {
internalUtils.Log.Err(err).Str("what", filepath.Join(s.path(cnst.UkiSysrootDir), path)).Msg("mkdir")
return err
}
// Bind mount it
err = syscall.Mount(s.path(path), filepath.Join(s.path(cnst.UkiSysrootDir), path), "", syscall.MS_BIND, "")
if err != nil {
internalUtils.Log.Err(err).Str("what", s.path(path)).
Str("where", filepath.Join(s.path(cnst.UkiSysrootDir), path)).Msg("bind mount")
return err
}
internalUtils.Log.Debug().Msg(fmt.Sprintf("Bind mounted %s to %s", s.path(path), filepath.Join(s.path(cnst.UkiSysrootDir), path)))
// Copy it over
out, err := internalUtils.CommandWithPath(fmt.Sprintf("cp -a %s %s", s.path(path), s.path(cnst.UkiSysrootDir)))
if err != nil {
internalUtils.Log.Err(err).Str("out", out).Str("what", s.path(path)).Str("where", s.path(cnst.UkiSysrootDir)).Msg("copying dir into sysroot")
}
continue
}
internalUtils.Log.Debug().Msg(fmt.Sprintf("%s is a mount point, skipping", s.path(path)))
internalUtils.Log.Debug().Str("what", path).Msg("mount point")
mountPoints = append(mountPoints, s.path(path))
continue
@ -862,7 +935,8 @@ func (s *State) UKIBootInitDagStep(g *herd.Graph) error {
symlinkPath := s.path(filepath.Join(cnst.UkiSysrootDir, file.Name()))
err = os.Symlink(target, symlinkPath)
if err != nil {
return fmt.Errorf("failed to create symlink: %w", err)
internalUtils.Log.Err(err).Str("from", target).Str("to", symlinkPath).Msg("Symlink")
dropToShell()
}
internalUtils.Log.Debug().Str("from", target).Str("to", symlinkPath).Msg("Symlinked file")
} else {
@ -870,51 +944,64 @@ func (s *State) UKIBootInitDagStep(g *herd.Graph) error {
content, _ := os.ReadFile(s.path(file.Name()))
newFilePath := s.path(filepath.Join(cnst.UkiSysrootDir, file.Name()))
_ = os.WriteFile(newFilePath, content, info.Mode())
internalUtils.Log.Debug().Msg(fmt.Sprintf("Copied %s to %s", s.path(file.Name()), newFilePath))
internalUtils.Log.Debug().Str("from", s.path(file.Name())).Str("to", newFilePath).Msg("Copied file")
}
}
// Now move the system mounts into the new dir
for _, d := range mountPoints {
newDir := filepath.Join(s.path(cnst.UkiSysrootDir), d)
err := os.MkdirAll(newDir, 0755)
if err != nil {
internalUtils.Log.Err(err).Str("what", newDir).Msg("mkdir")
if _, err := os.Stat(newDir); err != nil {
err = os.MkdirAll(newDir, 0755)
if err != nil {
internalUtils.Log.Err(err).Str("what", newDir).Msg("mkdir")
}
}
err = syscall.Mount(filepath.Join(s.path(), d), newDir, "", syscall.MS_MOVE, "")
err = syscall.Mount(d, newDir, "", syscall.MS_MOVE, "")
if err != nil {
internalUtils.Log.Err(err).Str("what", filepath.Join(s.Rootdir, d)).Str("where", newDir).Msg("move mount")
internalUtils.Log.Err(err).Str("what", d).Str("where", newDir).Msg("move mount")
continue
}
internalUtils.Log.Debug().Str("from", filepath.Join(s.path(), d)).Str("to", newDir).Msg("Mount moved")
internalUtils.Log.Debug().Str("from", d).Str("to", newDir).Msg("Mount moved")
}
// remount sysroot as readonly before chrooting
if err = syscall.Mount("", s.path(cnst.UkiSysrootDir), "", syscall.MS_REMOUNT|syscall.MS_RDONLY, ""); err != nil {
internalUtils.Log.Err(err).Msg("re-mounting sysroot as read only")
}
// Now chdir+chroot into the new dir
if err := unix.Chdir(s.path(cnst.UkiSysrootDir)); err != nil {
internalUtils.Log.Debug().Str("to", s.path(cnst.UkiSysrootDir)).Msg("Changing dir")
if err = unix.Chdir(s.path(cnst.UkiSysrootDir)); err != nil {
internalUtils.Log.Err(err).Msg("chdir")
return fmt.Errorf("failed change directory to new_root %v", err)
dropToShell()
}
internalUtils.Log.Debug().Msg("Chdir to sysroot done")
err = unix.Chroot(".")
if err != nil {
internalUtils.Log.Debug().Str("what", s.path(cnst.UkiSysrootDir)).Str("where", "/").Msg("Moving mount")
if err = unix.Mount(s.path(cnst.UkiSysrootDir), "/", "", unix.MS_MOVE, ""); err != nil {
internalUtils.Log.Err(err).Msg("mount move")
dropToShell()
}
internalUtils.Log.Debug().Str("to", ".").Msg("Chrooting")
if err = unix.Chroot("."); err != nil {
internalUtils.Log.Err(err).Msg("chroot")
return fmt.Errorf("failed to chroot %v", err)
dropToShell()
}
internalUtils.Log.Debug().Msg("Chroot to sysroot done")
// Print dag before exit, otherwise its never printed as we never exit the program
internalUtils.Log.Info().Msg(s.WriteDAG(g))
internalUtils.Log.Debug().Msg("Executing init callback!")
if err := unix.Exec("/sbin/init", []string{"/sbin/init"}, os.Environ()); err != nil {
internalUtils.Log.Err(err).Msg("running init")
// drop to emergency shell
if err := unix.Exec("/bin/bash", []string{"/bin/bash"}, os.Environ()); err != nil {
internalUtils.Log.Fatal().Msg("Could not drop to emergency shell")
}
dropToShell()
}
return nil
}))
}
func dropToShell() {
if err := unix.Exec("/bin/bash", []string{"/bin/bash"}, os.Environ()); err != nil {
if err := unix.Exec("/bin/sh", []string{"/bin/sh"}, os.Environ()); err != nil {
if err := unix.Exec("/sysroot/bin/bash", []string{"/sysroot/bin/bash"}, os.Environ()); err != nil {
if err := unix.Exec("/sysroot/bin/sh", []string{"/sysroot/bin/sh"}, os.Environ()); err != nil {
internalUtils.Log.Fatal().Msg("Could not drop to emergency shell")
}
}
}
}
}

21
pkg/mount/state.go
View File

@ -118,8 +118,7 @@ func (s *State) RunStageOp(stage string) func(context.Context) error {
case "initramfs":
// Not sure if it will work under UKI where the s.Rootdir is the current root already
internalUtils.Log.Info().Msg("Running initramfs stage")
chroot := internalUtils.NewChroot(s.Rootdir)
return chroot.RunCallback(func() error {
if internalUtils.IsUKI() {
output, _ := internalUtils.RunStage("initramfs")
internalUtils.Log.Debug().Msg(output.String())
err := internalUtils.CreateIfNotExists(constants.LogDir)
@ -131,7 +130,23 @@ func (s *State) RunStageOp(stage string) func(context.Context) error {
internalUtils.Log.Err(e).Msg("Writing log for initramfs stage")
}
return err
})
} else {
chroot := internalUtils.NewChroot(s.Rootdir)
return chroot.RunCallback(func() error {
output, _ := internalUtils.RunStage("initramfs")
internalUtils.Log.Debug().Msg(output.String())
err := internalUtils.CreateIfNotExists(constants.LogDir)
if err != nil {
return err
}
e := os.WriteFile(filepath.Join(constants.LogDir, "initramfs_stage.log"), output.Bytes(), os.ModePerm)
if e != nil {
internalUtils.Log.Err(e).Msg("Writing log for initramfs stage")
}
return err
})
}
default:
return errors.New("no stage that we know off")
}