url: update IDNA handling

Remove custom tests for invalid IDNA domains in url-idna.js in favor of
the more comprehensive official set.

PR-URL: #13362
Refs: whatwg/url#309
Refs: web-platform-tests/wpt#5976
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>

src/node_i18n.cc

@@ -450,6 +450,9 @@ int32_t ToUnicode(MaybeStackBuffer<char>* buf,
  &info,
  &status);
 
+ // Do not check info.errors like we do with ToASCII since ToUnicode always
+ // returns a string, despite any possible errors that may have occurred.
+
  if (status == U_BUFFER_OVERFLOW_ERROR) {
  status = U_ZERO_ERROR;
  buf->AllocateSufficientStorage(len);
@@ -477,9 +480,18 @@ int32_t ToUnicode(MaybeStackBuffer<char>* buf,
 int32_t ToASCII(MaybeStackBuffer<char>* buf,
  const char* input,
  size_t length,
- bool lenient) {
+ enum idna_mode mode) {
  UErrorCode status = U_ZERO_ERROR;
- uint32_t options = UIDNA_NONTRANSITIONAL_TO_ASCII | UIDNA_CHECK_BIDI;
+ uint32_t options = // CheckHyphens = false; handled later
+ UIDNA_CHECK_BIDI | // CheckBidi = true
+ UIDNA_CHECK_CONTEXTJ | // CheckJoiners = true
+ UIDNA_NONTRANSITIONAL_TO_ASCII; // Nontransitional_Processing
+ if (mode == IDNA_STRICT) {
+ options |= UIDNA_USE_STD3_RULES; // UseSTD3ASCIIRules = beStrict
+ // VerifyDnsLength = beStrict;
+ // handled later
+ }
+
  UIDNA* uidna = uidna_openUTS46(options, &status);
  if (U_FAILURE(status))
  return -1;
@@ -501,21 +513,17 @@ int32_t ToASCII(MaybeStackBuffer<char>* buf,
  &status);
  }
 
- // The WHATWG URL "domain to ASCII" algorithm explicitly sets the
- // VerifyDnsLength flag to false, which disables the domain name length
- // verification step in ToASCII (as specified by UTS #46). Unfortunately,
- // ICU4C's IDNA module does not support disabling this flag through `options`,
- // so just filter out the errors that may be caused by the verification step
- // afterwards.
- info.errors &= ~UIDNA_ERROR_EMPTY_LABEL;
- info.errors &= ~UIDNA_ERROR_LABEL_TOO_LONG;
- info.errors &= ~UIDNA_ERROR_DOMAIN_NAME_TOO_LONG;
-
- // These error conditions are mandated unconditionally by UTS #46 version
- // 9.0.0 (rev. 17), but were found to be incompatible with actual domain
- // names in the wild. As such, in the current UTS #46 draft (rev. 18) these
- // checks are made optional depending on the CheckHyphens flag, which will be
- // disabled in WHATWG URL's "domain to ASCII" algorithm soon.
+ // In UTS #46 which specifies ToASCII, certain error conditions are
+ // configurable through options, and the WHATWG URL Standard promptly elects
+ // to disable some of them to accomodate for real-world use cases.
+ // Unfortunately, ICU4C's IDNA module does not support disabling some of
+ // these options through `options` above, and thus continues throwing
+ // unnecessary errors. To counter this situation, we just filter out the
+ // errors that may have happened afterwards, before deciding whether to
+ // return an error from this function.
+
+ // CheckHyphens = false
+ // (Specified in the current UTS #46 draft rev. 18.)
  // Refs:
  // - https://github.com/whatwg/url/issues/53
  // - https://github.com/whatwg/url/pull/309
@@ -526,7 +534,14 @@ int32_t ToASCII(MaybeStackBuffer<char>* buf,
  info.errors &= ~UIDNA_ERROR_LEADING_HYPHEN;
  info.errors &= ~UIDNA_ERROR_TRAILING_HYPHEN;
 
- if (U_FAILURE(status) || (!lenient && info.errors != 0)) {
+ if (mode != IDNA_STRICT) {
+ // VerifyDnsLength = beStrict
+ info.errors &= ~UIDNA_ERROR_EMPTY_LABEL;
+ info.errors &= ~UIDNA_ERROR_LABEL_TOO_LONG;
+ info.errors &= ~UIDNA_ERROR_DOMAIN_NAME_TOO_LONG;
+ }
+
+ if (U_FAILURE(status) || (mode != IDNA_LENIENT && info.errors != 0)) {
  len = -1;
  buf->SetLength(0);
  } else {
@@ -564,9 +579,10 @@ static void ToASCII(const FunctionCallbackInfo<Value>& args) {
  Utf8Value val(env->isolate(), args[0]);
  // optional arg
  bool lenient = args[1]->BooleanValue(env->context()).FromJust();
+ enum idna_mode mode = lenient ? IDNA_LENIENT : IDNA_DEFAULT;
 
  MaybeStackBuffer<char> buf;
- int32_t len = ToASCII(&buf, *val, val.length(), lenient);
+ int32_t len = ToASCII(&buf, *val, val.length(), mode);
 
  if (len < 0) {
  return env->ThrowError("Cannot convert name to ASCII");

src/node_i18n.h

@@ -37,10 +37,26 @@ namespace i18n {
 
 bool InitializeICUDirectory(const std::string& path);
 
+enum idna_mode {
+ // Default mode for maximum compatibility.
+ IDNA_DEFAULT,
+ // Ignore all errors in IDNA conversion, if possible.
+ IDNA_LENIENT,
+ // Enforce STD3 rules (UseSTD3ASCIIRules) and DNS length restrictions
+ // (VerifyDnsLength). Corresponds to `beStrict` flag in the "domain to ASCII"
+ // algorithm.
+ IDNA_STRICT
+};
+
+// Implements the WHATWG URL Standard "domain to ASCII" algorithm.
+// https://url.spec.whatwg.org/#concept-domain-to-ascii
 int32_t ToASCII(MaybeStackBuffer<char>* buf,
  const char* input,
  size_t length,
- bool lenient = false);
+ enum idna_mode mode = IDNA_DEFAULT);
+
+// Implements the WHATWG URL Standard "domain to Unicode" algorithm.
+// https://url.spec.whatwg.org/#concept-domain-to-unicode
 int32_t ToUnicode(MaybeStackBuffer<char>* buf,
  const char* input,
  size_t length);