ydb-go-sdk token in custom credentials object can leak through logs

Impact

Since ydb-go-sdk/v3.48.6 if you use a custom credentials object (implementation of interface Credentials) it may leak into logs. This happens because this object could be serialized into an error message using fmt.Errorf("something went wrong (credentials: %q)", credentials) during connection to the YDB server. Printf func use placeholder %q for string representation of argument with quotes. If an argument implements interface fmt.Stringer, it will used through String() func. In other cases used fallback - serialization with reflection.

If such logging occurred, a malicious user with access to logs could read sensitive information (i.e. credentials) information and use it to get access to the database.

Who is impacted: applications with custom credentials object with an explicit token field.

A leak could have occurred if all of these conditions were met simultaneously:

1. The credentials object does not implement the fmt.Stringer interface (does not have a String() method) - potentially these are custom credentials. Official credentials have a String() method.
2. There was an error connecting to YDB during driver creation via ydb.Open(...).
3. Some logging system was configured (ydb-go-sdk does not log such errors by default).
4. The connection error was logged into a system that a malicious user had access to.

Patches

ydb-go-sdk contains this problem in versions from v3.48.6 to v3.53.2. The fix for this problem has been released in version v3.53.3 (PR).

Workarounds

Implement the fmt.Stringer interface in your custom credentials type with explicit stringify of object state.