initrd/bootstrap.go
2023-12-17 17:16:53 +01:00

171 lines
3.4 KiB
Go

package main
import (
"bytes"
"fmt"
"io"
"log"
"net/http"
"os"
"path/filepath"
"strings"
config "novit.tech/direktil/pkg/bootstrapconfig"
)
func bootstrap(cfg *config.Config) {
if cfg.Bootstrap.Dev == "" {
fatalf("bootstrap device not defined!")
}
const bsDir = "/bootstrap"
os.MkdirAll(bsDir, 0700)
run("mount", cfg.Bootstrap.Dev, bsDir)
baseDir := filepath.Join(bsDir, bootVersion)
sysCfgPath := filepath.Join(baseDir, "config.yaml")
if _, err := os.Stat(sysCfgPath); os.IsNotExist(err) {
log.Printf("bootstrap %q does not exist", bootVersion)
seed := cfg.Bootstrap.Seed
if seed == "" {
fatalf("boostrap seed not defined, admin required")
}
log.Printf("seeding bootstrap from %s", seed)
err = os.MkdirAll(baseDir, 0700)
if err != nil {
fatalf("failed to create bootstrap dir: %v", err)
}
bootstrapFile := filepath.Join(baseDir, "bootstrap.tar")
err = func() (err error) {
resp, err := http.Get(seed)
if err != nil {
return
}
if resp.StatusCode != http.StatusOK {
err = fmt.Errorf("bad HTTP status: %s", resp.Status)
return
}
defer resp.Body.Close()
out, err := os.Create(bootstrapFile)
if err != nil {
return
}
defer out.Close()
_, err = io.Copy(out, resp.Body)
return
}()
if err != nil {
fatalf("seeding failed: %v", err)
}
log.Print("unpacking bootstrap file")
run("tar", "xvf", bootstrapFile, "-C", baseDir)
}
layersDir = baseDir
layersOverride["modules"] = "/modules.sqfs"
sysCfg := applyConfig(sysCfgPath, false)
localGenDir := filepath.Join(bsDir, "local-gen")
// vpns are v2+
for _, vpn := range sysCfg.VPNs {
setupVPN(vpn, localGenDir)
}
// mounts are v2+
for _, mount := range sysCfg.Mounts {
log.Print("mount ", mount.Dev, " to system's ", mount.Path)
path := filepath.Join("/system", mount.Path)
os.MkdirAll(path, 0755)
args := []string{mount.Dev, path}
if mount.Type != "" {
args = append(args, "-t", mount.Type)
}
if mount.Options != "" {
args = append(args, "-o", mount.Options)
}
run("mount", args...)
}
// setup root user
if ph := sysCfg.RootUser.PasswordHash; ph != "" {
log.Print("setting root's password")
setUserPass("root", ph)
}
if ak := sysCfg.RootUser.AuthorizedKeys; len(ak) != 0 {
log.Print("setting root's authorized keys")
setAuthorizedKeys(ak)
}
}
func setUserPass(user, passwordHash string) {
const fpath = "/system/etc/shadow"
ba, err := os.ReadFile(fpath)
if err != nil {
fatalf("failed to read shadow: %v", err)
}
lines := bytes.Split(ba, []byte{'\n'})
buf := new(bytes.Buffer)
for _, line := range lines {
line := string(line)
p := strings.Split(line, ":")
if len(p) < 2 || p[0] != user {
buf.WriteString(line)
buf.WriteByte('\n')
continue
}
p[1] = passwordHash
line = strings.Join(p, ":")
buf.WriteString(line)
buf.WriteByte('\n')
}
err = os.WriteFile(fpath, buf.Bytes(), 0600)
if err != nil {
fatalf("failed to write shadow: %v", err)
}
}
func setAuthorizedKeys(ak []string) {
buf := new(bytes.Buffer)
for _, k := range ak {
buf.WriteString(k)
buf.WriteByte('\n')
}
const sshDir = "/system/root/.ssh"
err := os.MkdirAll(sshDir, 0700)
if err != nil {
fatalf("failed to create %s: %v", sshDir, err)
}
err = os.WriteFile(filepath.Join(sshDir, "authorized_keys"), buf.Bytes(), 0600)
if err != nil {
fatalf("failed to write authorized keys: %v", err)
}
}