[VALIDATOR-483] DomainValidator conversion to ASCII uses an obsoleted standard

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: Routines

Environment

Java openjdk 11 on Linux

Language

Java

• Assignee: Unassigned
• Reporter: Julien Bernard
• Created: 11/Feb/22 04:20
• Updated: 22/Sep/22 20:11

Description

DomainValidator uses java.net.IDN for its conversion to ASCII which is based on RFC3490 (IDNA 2003) that is obsoleted by RFC 5891 (IDNA 2008).

An external library such as ICU4J may be used for an IDNA 2008 compliant conversion:

int flags = IDNA.CHECK_BIDI
       | IDNA.CHECK_CONTEXTJ
       | IDNA.CHECK_CONTEXTO
       | IDNA.NONTRANSITIONAL_TO_ASCII
       | IDNA.USE_STD3_RULES;
IDNA idna = IDNA.getUTS46Instance(flags);
IDNA.Info info = new IDNA.Info();
StringBuilder domainAscii = new StringBuilder();
idna.nameToASCII(domain, domainAscii, info);
// check error with info.hasErrors()