Fix a bug where Synapse fails to start if a signing key file contains an empty line. (#13738)

2 files changed, 13 insertions, 1 deletions

diff --git a/changelog.d/13738.bugfix b/changelog.d/13738.bugfix
new file mode 100644

index 0000000000..d64fa0b4de
--- /dev/null
+++ b/changelog.d/13738.bugfix
@@ -0,0 +1 @@
+Fix a bug where Synapse fails to start if a signing key file contains an empty line.
\ No newline at end of file
diff --git a/synapse/config/key.py b/synapse/config/key.py

index cc75efdf8f..f3dc4df695 100644
--- a/synapse/config/key.py
+++ b/synapse/config/key.py
@@ -217,7 +217,18 @@ class KeyConfig(Config):
 
         signing_keys = self.read_file(signing_key_path, name)
         try:
-            return read_signing_keys(signing_keys.splitlines(True))
+            loaded_signing_keys = read_signing_keys(
+                [
+                    signing_key_line
+                    for signing_key_line in signing_keys.splitlines(keepends=False)
+                    if signing_key_line.strip()
+                ]
+            )
+
+            if not loaded_signing_keys:
+                raise ConfigError(f"No signing keys in file {signing_key_path}")
+
+            return loaded_signing_keys
         except Exception as e:
             raise ConfigError("Error reading %s: %s" % (name, str(e)))