From c46f7d63165fabcb6ca21d4ee663f4b9da8ae36a Mon Sep 17 00:00:00 2001
From: Kegan Dougal <kegan@matrix.org>
Date: Tue, 27 Jul 2021 18:30:38 +0100
Subject: [PATCH] Apparently only the current version supports uploading keys

---
 sytest-whitelist        |  1 +
 userapi/internal/api.go | 13 +++++++------
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/sytest-whitelist b/sytest-whitelist
index d9efa8264..6bb3d770a 100644
--- a/sytest-whitelist
+++ b/sytest-whitelist
@@ -546,6 +546,7 @@ Responds correctly when backup is empty
 Can backup keys
 Can update keys with better versions
 Will not update keys with worse versions
+Will not back up to an old backup version
 Can create more than 10 backup versions
 Can delete backup
 Deleted & recreated backups are empty
diff --git a/userapi/internal/api.go b/userapi/internal/api.go
index 006e1eff1..cd760e41c 100644
--- a/userapi/internal/api.go
+++ b/userapi/internal/api.go
@@ -444,10 +444,6 @@ func (a *UserInternalAPI) QueryOpenIDToken(ctx context.Context, req *api.QueryOp
 }
 
 func (a *UserInternalAPI) PerformKeyBackup(ctx context.Context, req *api.PerformKeyBackupRequest, res *api.PerformKeyBackupResponse) {
-	logrus.Infof("PerformKeyBackup REQ= %+v", *req)
-	defer func() {
-		logrus.Infof("PerformKeyBackup RESP= %+v", *res)
-	}()
 	// Delete metadata
 	if req.DeleteBackup {
 		if req.Version == "" {
@@ -488,8 +484,8 @@ func (a *UserInternalAPI) PerformKeyBackup(ctx context.Context, req *api.Perform
 }
 
 func (a *UserInternalAPI) uploadBackupKeys(ctx context.Context, req *api.PerformKeyBackupRequest, res *api.PerformKeyBackupResponse) {
-	// ensure the version metadata exists
-	version, _, _, _, deleted, err := a.AccountDB.GetKeyBackup(ctx, req.UserID, req.Version)
+	// you can only upload keys for the CURRENT version
+	version, _, _, _, deleted, err := a.AccountDB.GetKeyBackup(ctx, req.UserID, "")
 	if err != nil {
 		res.Error = fmt.Sprintf("failed to query version: %s", err)
 		return
@@ -498,6 +494,11 @@ func (a *UserInternalAPI) uploadBackupKeys(ctx context.Context, req *api.Perform
 		res.Error = "backup was deleted"
 		return
 	}
+	if version != req.Version {
+		res.BadInput = true
+		res.Error = fmt.Sprintf("%s isn't the current version, %s is.", req.Version, version)
+		return
+	}
 	res.Exists = true
 	res.Version = version