ssh: Implement authentication for new ssh server

internal/wisski/ingredient/barrel/barrel.go

@@ -1,6 +1,8 @@
 package barrel
 
 import (
+	"path/filepath"
+
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/locker"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/mstore"
@@ -13,3 +15,11 @@ type Barrel struct {
 	Locker *locker.Locker
 	MStore *mstore.MStore
 }
+
+func (barrel *Barrel) DataPath() string {
+	return filepath.Join(barrel.FilesystemBase, "data")
+}
+
+func (barrel *Barrel) AuthorizedKeysPath() string {
+	return filepath.Join(barrel.DataPath(), "authorized_keys")
+}

internal/wisski/ingredient/barrel/ssh/ssh.go

@@ -0,0 +1,32 @@
+package ssh
+
+import (
+	"io"
+
+	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient"
+	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/barrel"
+	"github.com/FAU-CDI/wisski-distillery/pkg/environment"
+	"github.com/FAU-CDI/wisski-distillery/pkg/sshx"
+	"github.com/gliderlabs/ssh"
+)
+
+type SSH struct {
+	ingredient.Base
+	Barrel *barrel.Barrel
+}
+
+func (ssh *SSH) Keys() ([]ssh.PublicKey, error) {
+	file, err := ssh.Environment.Open(ssh.Barrel.AuthorizedKeysPath())
+	if environment.IsNotExist(err) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	bytes, err := io.ReadAll(file)
+	if err != nil {
+		return nil, err
+	}
+	return sshx.ParseAllKeys(bytes), nil
+}

internal/wisski/wisski.go

@@ -8,6 +8,7 @@ import (
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/barrel"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/barrel/drush"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/barrel/provisioner"
+	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/barrel/ssh"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/bookkeeping"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/info"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/locker"
@@ -76,6 +77,10 @@ func (wisski *WissKI) Info() *info.Info {
 	return export[*info.Info](wisski)
 }
 
+func (wisski *WissKI) SSH() *ssh.SSH {
+	return export[*ssh.SSH](wisski)
+}
+
 //
 // All components
 // THESE SHOULD NEVER BE CALLED DIRECTLY
@@ -112,5 +117,7 @@ func (wisski *WissKI) allIngredients() []initFunc {
 		auto[*drush.Drush],
 
 		auto[*reserve.Reserve],
+
+		auto[*ssh.SSH],
 	}
 }