Bug 1674819 - Fixup a51fae403328, enum type may be signed. r=bbeurdouche

Differential Revision: https://phabricator.services.mozilla.com/D102964

--HG--
extra : moz-landing-system : lando

lib/ssl/ssl3exthandle.c

@@ -921,7 +921,7 @@ ssl_ParseSessionTicket(sslSocket *ss, const SECItem *decryptedTicket,
 #ifndef UNSAFE_FUZZER_MODE
     PORT_Assert(temp < ssl_auth_size);
 #else
-    temp %= (8 * sizeof(SSLAuthType));
+    temp %= (8 * sizeof(SSLAuthType)) - 1;
 #endif
 
     parsedTicket->authType = (SSLAuthType)temp;