gitle/main.go
2022-08-12 17:13:18 -06:00

112 lines
2.5 KiB
Go

package main
import (
"bufio"
"bytes"
"fmt"
"io/ioutil"
"log"
"os"
"golang.org/x/crypto/ssh"
"suah.dev/gitkit"
"suah.dev/protect"
)
func envOr(name string, def string) string {
s := os.Getenv(name)
if s == "" {
return def
}
return s
}
func main() {
repos := envOr("GITLE_REPOS", "/var/gitle/repos")
akSrc := envOr("GITLE_AUTH_KEYS", "/var/gitle/authorized_keys")
hostKey := envOr("GITLE_HOST_KEY", "/var/gitle/host_key")
faFPs := envOr("GITLE_FULL_ACCESS_FINGREPRINTS", "/var/gitle/full_access_fingreprints")
port := envOr("GITLE_PORT", ":2222")
protect.Unveil(repos, "rwc")
protect.Unveil(akSrc, "r")
protect.Unveil(faFPs, "r")
protect.Unveil(hostKey, "r")
protect.Unveil("/dev", "r")
protect.Unveil("/dev/null", "rw")
protect.Unveil("/usr/local/bin/", "rx")
protect.UnveilBlock()
server := gitkit.NewSSH(gitkit.Config{
Dir: repos,
AutoCreate: true,
})
fa, err := ioutil.ReadFile(faFPs)
if err != nil {
log.Fatalf("can't load full_access_fingreprints file: %s, err: %v", faFPs, err)
}
fpMap := map[string]bool{}
scanner := bufio.NewScanner(bytes.NewReader(fa))
for scanner.Scan() {
fp := scanner.Text()
fpMap[fp] = true
}
akb, err := ioutil.ReadFile(akSrc)
if err != nil {
log.Fatalf("can't load authorized keys file: %s, err: %v", akSrc, err)
}
akMap := map[string]bool{}
for len(akb) > 0 {
pubKey, _, _, rest, err := ssh.ParseAuthorizedKey(akb)
if err != nil {
log.Fatalf("failed to read pubKey entry: %v", err)
}
akMap[string(pubKey.Marshal())] = true
akb = rest
}
b, err := ioutil.ReadFile(hostKey)
if err != nil {
log.Fatalf("failed to read %s: %v", hostKey, err)
}
pk, err := ssh.ParsePrivateKey(b)
if err != nil {
log.Fatalf("failed to parse %s: %v", hostKey, err)
}
server.SSHConfig = &ssh.ServerConfig{
ServerVersion: "SSH-2.0-gitle",
PublicKeyCallback: func(conn ssh.ConnMetadata, pubKey ssh.PublicKey) (*ssh.Permissions, error) {
if akMap[string(pubKey.Marshal())] {
fp := ssh.FingerprintSHA256(pubKey)
isRO := "yes"
if fpMap[fp] {
isRO = "no"
}
return &ssh.Permissions{
Extensions: map[string]string{
"pubkey-fp": fp,
"key-id": fp,
},
CriticalOptions: map[string]string{
"is-ro": isRO,
},
}, nil
}
return nil, fmt.Errorf("unknown public key for %q", conn.User())
},
}
server.SSHConfig.AddHostKey(pk)
server.SetupDone = true
err = server.ListenAndServe(port)
if err != nil {
log.Fatalf("failed to listen: %v\n", err)
}
}