wip

Signed-off-by: Sumner Evans <sumner@beeper.com>

client.go

@@ -21,6 +21,7 @@ import (
 	"go.mau.fi/util/retryafter"
 	"maunium.net/go/maulogger/v2/maulogadapt"
 
+	"maunium.net/go/mautrix/crypto/backup"
 	"maunium.net/go/mautrix/event"
 	"maunium.net/go/mautrix/id"
 	"maunium.net/go/mautrix/pushrules"
@@ -1944,7 +1945,7 @@ func (cli *Client) GetKeyChanges(ctx context.Context, from, to string) (resp *Re
 // GetKeyBackup retrieves the keys from the backup.
 //
 // See: https://spec.matrix.org/v1.9/client-server-api/#get_matrixclientv3room_keyskeys
-func (cli *Client) GetKeyBackup(ctx context.Context, version string) (resp *RespRoomKeys, err error) {
+func (cli *Client) GetKeyBackup(ctx context.Context, version string) (resp *RespRoomKeys[backup.EncryptedMegolmSessionData], err error) {
 	urlPath := cli.BuildURLWithQuery(ClientURLPath{"v3", "room_keys", "keys"}, map[string]string{
 		"version": version,
 	})
@@ -1977,7 +1978,7 @@ func (cli *Client) DeleteKeyBackup(ctx context.Context, version string) (resp *R
 // GetKeyBackupForRoom retrieves the keys from the backup for the given room.
 //
 // See: https://spec.matrix.org/v1.9/client-server-api/#get_matrixclientv3room_keyskeysroomid
-func (cli *Client) GetKeyBackupForRoom(ctx context.Context, version string, roomID id.RoomID) (resp *RespRoomKeyBackup, err error) {
+func (cli *Client) GetKeyBackupForRoom(ctx context.Context, version string, roomID id.RoomID) (resp *RespRoomKeyBackup[backup.EncryptedMegolmSessionData], err error) {
 	urlPath := cli.BuildURLWithQuery(ClientURLPath{"v3", "room_keys", "keys", roomID.String()}, map[string]string{
 		"version": version,
 	})
@@ -2011,7 +2012,7 @@ func (cli *Client) DeleteKeysFromBackupForRoom(ctx context.Context, version stri
 // GetKeyBackupForRoomAndSession retrieves a key from the backup.
 //
 // See: https://spec.matrix.org/v1.9/client-server-api/#get_matrixclientv3room_keyskeysroomidsessionid
-func (cli *Client) GetKeyBackupForRoomAndSession(ctx context.Context, version string, roomID id.RoomID, sessionID id.SessionID) (resp *RespKeyBackupData, err error) {
+func (cli *Client) GetKeyBackupForRoomAndSession(ctx context.Context, version string, roomID id.RoomID, sessionID id.SessionID) (resp *RespKeyBackupData[backup.EncryptedMegolmSessionData], err error) {
 	urlPath := cli.BuildURLWithQuery(ClientURLPath{"v3", "room_keys", "keys", roomID.String(), sessionID.String()}, map[string]string{
 		"version": version,
 	})
@@ -2044,7 +2045,7 @@ func (cli *Client) DeleteKeysInBackupForRoomAndSession(ctx context.Context, vers
 // GetKeyBackupLatestVersion returns information about the latest backup version.
 //
 // See: https://spec.matrix.org/v1.9/client-server-api/#get_matrixclientv3room_keysversion
-func (cli *Client) GetKeyBackupLatestVersion(ctx context.Context) (resp *RespRoomKeysVersion, err error) {
+func (cli *Client) GetKeyBackupLatestVersion(ctx context.Context) (resp *RespRoomKeysVersion[backup.MegolmAuthData], err error) {
 	urlPath := cli.BuildClientURL("v3", "room_keys", "version")
 	_, err = cli.MakeRequest(ctx, http.MethodGet, urlPath, nil, &resp)
 	return
@@ -2062,7 +2063,7 @@ func (cli *Client) CreateKeyBackupVersion(ctx context.Context, req *ReqRoomKeysV
 // GetKeyBackupVersion returns information about an existing key backup.
 //
 // See: https://spec.matrix.org/v1.9/client-server-api/#get_matrixclientv3room_keysversionversion
-func (cli *Client) GetKeyBackupVersion(ctx context.Context, version string) (resp *RespRoomKeysVersion, err error) {
+func (cli *Client) GetKeyBackupVersion(ctx context.Context, version string) (resp *RespRoomKeysVersion[backup.MegolmAuthData], err error) {
 	urlPath := cli.BuildClientURL("v3", "room_keys", "version", version)
 	_, err = cli.MakeRequest(ctx, http.MethodGet, urlPath, nil, &resp)
 	return

crypto/backup/ed25519aessha2.go

@@ -1,12 +1,14 @@
 package backup
 
 import (
+	"crypto/ed25519"
+
 	"maunium.net/go/mautrix/crypto/signatures"
 	"maunium.net/go/mautrix/id"
 )
 
 // MegolmAuthData is the auth_data when the key backup is created with
-// the [id.KeyBackupAlgorithmCurve25519AESSHA2] algorithm as defined in
+// the [id.KeyBackupAlgorithmMegolmBackupV1] algorithm as defined in
 // [Section 11.12.3.2.2 of the Spec].
 //
 // [Section 11.12.3.2.2 of the Spec]: https://spec.matrix.org/v1.9/client-server-api/#backup-algorithm-mmegolm_backupv1curve25519-aes-sha2
@@ -15,11 +17,23 @@ type MegolmAuthData struct {
 	Signatures signatures.Signatures `json:"signatures"`
 }
 
-// MegolmSessionData is the session_data when the key backup is created
-// with the [id.KeyBackupAlgorithmCurve25519AESSHA2] algorithm as defined in
-// [Section 11.12.3.2.2 of the Spec].
+// EncryptedSessionData is the encrypted session_data field of a key backup as
+// defined in [Section 11.12.3.2.2 of the Spec].
+//
+// The type parameter B represents the format of the session data contained in
+// the encrypted payload.
 //
 // [Section 11.12.3.2.2 of the Spec]: https://spec.matrix.org/v1.9/client-server-api/#backup-algorithm-mmegolm_backupv1curve25519-aes-sha2
+type EncryptedSessionData[T any] struct {
+	Ciphertext []byte `json:"ciphertext"`
+	Ephemeral  []byte `json:"ephemeral"`
+	Mac        []byte `json:"mac"`
+}
+
+func (e *EncryptedSessionData[T]) Encrypt(recoveryKey ed25519.PrivateKey) (*T, error) {
+	return nil, nil
+}
+
 type MegolmSessionData struct {
 	Algorithm                    id.Algorithm               `json:"algorithm"`
 	ForwardingCurve25519KeyChain []string                   `json:"forwarding_curve25519_key_chain"`

crypto/machine.go

@@ -15,6 +15,7 @@ import (
 
 	"github.com/rs/zerolog"
 
+	"maunium.net/go/mautrix/crypto/olm"
 	"maunium.net/go/mautrix/crypto/ssss"
 	"maunium.net/go/mautrix/id"
 
@@ -688,3 +689,52 @@ func (mach *OlmMachine) ExpiredKeyDeleteLoop(ctx context.Context) {
 		}
 	}
 }
+
+func (mach *OlmMachine) DownloadAndStoreLatestKeyBackup(ctx context.Context) error {
+	log := mach.machOrContextLog(ctx).With().
+		Str("action", "download and store latest key backup").
+		Logger()
+	versionInfo, err := mach.Client.GetKeyBackupLatestVersion(ctx)
+	if err != nil {
+		return err
+	}
+
+	if versionInfo.Algorithm != id.KeyBackupAlgorithmMegolmBackupV1 {
+		return fmt.Errorf("unsupported key backup algorithm: %s", versionInfo.Algorithm)
+	}
+
+	log = log.With().
+		Int("count", versionInfo.Count).
+		Str("etag", versionInfo.ETag).
+		Str("key_backup_version", versionInfo.Version).
+		Logger()
+
+	if versionInfo.Count == 0 {
+		log.Debug().Msg("No keys found in key backup")
+		return nil
+	}
+
+	keys, err := mach.Client.GetKeyBackup(ctx, versionInfo.Version)
+	if err != nil {
+		return err
+	}
+
+	for roomID, backup := range keys.Rooms {
+		fmt.Printf("Sessions for %s\n", roomID)
+		for sessionID, keyBackupData := range backup.Sessions {
+			// TODO
+			fmt.Printf("\t%s: %v\n", sessionID, keyBackupData)
+
+			olm.NewInboundGroupSession([]byte(keyBackupData.SessionData.SessionKey))
+
+			err := mach.CryptoStore.PutGroupSession(ctx, roomID, keyBackupData.SessionData.SenderKey, sessionID, &InboundGroupSession{
+				Internal: olm.InboundGroupSession,
+			})
+			if err != nil {
+				return nil
+			}
+		}
+	}
+
+	return nil
+}

responses.go

@@ -596,27 +596,27 @@ type RespRoomKeysVersionCreate struct {
 	Version string `json:"version"`
 }
 
-type RespRoomKeysVersion struct {
+type RespRoomKeysVersion[A any] struct {
 	Algorithm id.KeyBackupAlgorithm `json:"algorithm"`
-	AuthData  json.RawMessage       `json:"auth_data"`
+	AuthData  A                     `json:"auth_data"`
 	Count     int                   `json:"count"`
 	ETag      string                `json:"etag"`
 	Version   string                `json:"version"`
 }
 
-type RespRoomKeys struct {
-	Rooms map[id.RoomID]RespRoomKeyBackup `json:"rooms"`
+type RespRoomKeys[S any] struct {
+	Rooms map[id.RoomID]RespRoomKeyBackup[S] `json:"rooms"`
 }
 
-type RespRoomKeyBackup struct {
-	Sessions map[id.SessionID]RespKeyBackupData `json:"sessions"`
+type RespRoomKeyBackup[S any] struct {
+	Sessions map[id.SessionID]RespKeyBackupData[S] `json:"sessions"`
 }
 
-type RespKeyBackupData struct {
-	FirstMessageIndex int             `json:"first_message_index"`
-	ForwardedCount    int             `json:"forwarded_count"`
-	IsVerified        bool            `json:"is_verified"`
-	SessionData       json.RawMessage `json:"session_data"`
+type RespKeyBackupData[S any] struct {
+	FirstMessageIndex int  `json:"first_message_index"`
+	ForwardedCount    int  `json:"forwarded_count"`
+	IsVerified        bool `json:"is_verified"`
+	SessionData       S    `json:"session_data"`
 }
 
 type RespRoomKeysUpdate struct {