Guard authenticate() entry point against exceptions

manifest.json

@@ -1,6 +1,6 @@
 {
   "name": "vsql_oauth2",
-  "version": "0.0.2",
+  "version": "0.0.3",
   "description": "OAuth2/OIDC JWT authentication method for VillageSQL",
   "author": "VillageSQL Contributors",
   "license": "GPL-2.0"

src/extension.cc

@@ -220,7 +220,7 @@ bool auto_grant_enabled() { return g_auto_grant; }
 // Decision to the auth context. Fail closed: only an explicit accept returns
 // AuthResult::kOk.
 vsql::preview_auth::AuthResult
-authenticate(vsql::preview_auth::AuthContext &c) {
+authenticate_impl(vsql::preview_auth::AuthContext &c) {
   using vsql::preview_auth::AuthResult;
 
   // Read the token. An empty span means the client disconnected or sent a
@@ -289,6 +289,27 @@ authenticate(vsql::preview_auth::AuthContext &c) {
   return AuthResult::kOk;
 }
 
+// Thin wrapper: authenticate_impl's own body does real allocating work
+// (std::string construction from the raw packet, build_config/
+// build_key_resolver's std::function/std::string copies, the two
+// std::vector<const char*> role-pointer buffers) outside of the
+// already-guarded evaluate()/map_roles()/JwksCache calls it makes. The VEF
+// SDK does not catch exceptions at the preview/auth entry-point boundary, so
+// an escaping bad_alloc here would crash the whole server rather than just
+// fail this one login -- fail closed on any exception, consistent with
+// every other rejection path in authenticate_impl.
+vsql::preview_auth::AuthResult
+authenticate(vsql::preview_auth::AuthContext &c) {
+  using vsql::preview_auth::AuthResult;
+  try {
+    return authenticate_impl(c);
+  } catch (const std::exception &) {
+    return AuthResult::kError;
+  } catch (...) {
+    return AuthResult::kError;
+  }
+}
+
 // The client-side auth plugin the server advertises as the default for this
 // method. We use the built-in "mysql_clear_password": it ships with every
 // client and driver, so a client that does not name a plugin of its own is