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996 lines
33 KiB
C++
996 lines
33 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This code is made available to you under your choice of the following sets
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* of licensing terms:
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*/
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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/* Copyright 2014 Mozilla Contributors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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// This code attempts to implement RFC6125 name matching.
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//
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// In this code, identifiers are classified as either "presented" or
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// "reference" identifiers are defined in
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// http://tools.ietf.org/html/rfc6125#section-1.8. A "presented identifier" is
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// one in the subjectAltName of the certificate, or sometimes within a CN of
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// the certificate's subject. The "reference identifier" is the one we are
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// being asked to match the certificate against.
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//
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// On Windows and maybe other platforms, OS-provided IP address parsing
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// functions might fail if the protocol (IPv4 or IPv6) has been disabled, so we
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// can't rely on them.
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#include "pkix/bind.h"
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#include "pkixutil.h"
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namespace mozilla { namespace pkix {
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namespace {
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// GeneralName ::= CHOICE {
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// otherName [0] OtherName,
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// rfc822Name [1] IA5String,
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// dNSName [2] IA5String,
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// x400Address [3] ORAddress,
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// directoryName [4] Name,
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// ediPartyName [5] EDIPartyName,
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// uniformResourceIdentifier [6] IA5String,
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// iPAddress [7] OCTET STRING,
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// registeredID [8] OBJECT IDENTIFIER }
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MOZILLA_PKIX_ENUM_CLASS GeneralNameType : uint8_t
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{
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dNSName = der::CONTEXT_SPECIFIC | 2,
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iPAddress = der::CONTEXT_SPECIFIC | 7,
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};
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MOZILLA_PKIX_ENUM_CLASS FallBackToCommonName { No = 0, Yes = 1 };
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Result SearchForName(const Input* subjectAltName, Input subject,
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GeneralNameType referenceIDType,
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Input referenceID,
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FallBackToCommonName fallBackToCommonName,
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/*out*/ bool& foundMatch);
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Result SearchWithinRDN(Reader& rdn,
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GeneralNameType referenceIDType,
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Input referenceID,
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/*in/out*/ bool& foundMatch);
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Result SearchWithinAVA(Reader& rdn,
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GeneralNameType referenceIDType,
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Input referenceID,
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/*in/out*/ bool& foundMatch);
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Result MatchPresentedIDWithReferenceID(GeneralNameType referenceIDType,
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Input presentedID,
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Input referenceID,
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/*out*/ bool& foundMatch);
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uint8_t LocaleInsensitveToLower(uint8_t a);
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bool StartsWithIDNALabel(Input id);
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MOZILLA_PKIX_ENUM_CLASS ValidDNSIDMatchType
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{
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ReferenceID = 0,
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PresentedID = 1,
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};
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bool IsValidDNSID(Input hostname, ValidDNSIDMatchType matchType);
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} // unnamed namespace
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bool IsValidReferenceDNSID(Input hostname);
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bool IsValidPresentedDNSID(Input hostname);
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bool ParseIPv4Address(Input hostname, /*out*/ uint8_t (&out)[4]);
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bool ParseIPv6Address(Input hostname, /*out*/ uint8_t (&out)[16]);
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bool PresentedDNSIDMatchesReferenceDNSID(Input presentedDNSID,
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Input referenceDNSID);
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// Verify that the given end-entity cert, which is assumed to have been already
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// validated with BuildCertChain, is valid for the given hostname. hostname is
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// assumed to be a string representation of an IPv4 address, an IPv6 addresss,
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// or a normalized ASCII (possibly punycode) DNS name.
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Result
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CheckCertHostname(Input endEntityCertDER, Input hostname)
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{
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BackCert cert(endEntityCertDER, EndEntityOrCA::MustBeEndEntity, nullptr);
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Result rv = cert.Init();
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if (rv != Success) {
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return rv;
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}
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const Input* subjectAltName(cert.GetSubjectAltName());
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Input subject(cert.GetSubject());
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// For backward compatibility with legacy certificates, we fall back to
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// searching for a name match in the subject common name for DNS names and
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// IPv4 addresses. We don't do so for IPv6 addresses because we do not think
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// there are many certificates that would need such fallback, and because
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// comparisons of string representations of IPv6 addresses are particularly
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// error prone due to the syntactic flexibility that IPv6 addresses have.
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//
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// IPv4 and IPv6 addresses are represented using the same type of GeneralName
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// (iPAddress); they are differentiated by the lengths of the values.
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bool found;
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uint8_t ipv6[16];
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uint8_t ipv4[4];
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if (IsValidReferenceDNSID(hostname)) {
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rv = SearchForName(subjectAltName, subject, GeneralNameType::dNSName,
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hostname, FallBackToCommonName::Yes, found);
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} else if (ParseIPv6Address(hostname, ipv6)) {
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rv = SearchForName(subjectAltName, subject, GeneralNameType::iPAddress,
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Input(ipv6), FallBackToCommonName::No, found);
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} else if (ParseIPv4Address(hostname, ipv4)) {
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rv = SearchForName(subjectAltName, subject, GeneralNameType::iPAddress,
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Input(ipv4), FallBackToCommonName::Yes, found);
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} else {
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return Result::ERROR_BAD_CERT_DOMAIN;
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}
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if (rv != Success) {
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return rv;
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}
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if (!found) {
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return Result::ERROR_BAD_CERT_DOMAIN;
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}
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return Success;
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}
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namespace {
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Result
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SearchForName(/*optional*/ const Input* subjectAltName,
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Input subject,
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GeneralNameType referenceIDType,
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Input referenceID,
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FallBackToCommonName fallBackToCommonName,
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/*out*/ bool& foundMatch)
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{
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Result rv;
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foundMatch = false;
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// RFC 6125 says "A client MUST NOT seek a match for a reference identifier
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// of CN-ID if the presented identifiers include a DNS-ID, SRV-ID, URI-ID, or
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// any application-specific identifier types supported by the client."
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// Accordingly, we only consider CN-IDs if there are no DNS-IDs in the
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// subjectAltName.
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//
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// RFC 6125 says that IP addresses are out of scope, but for backward
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// compatibility we accept them, by considering IP addresses to be an
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// "application-specific identifier type supported by the client."
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//
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// TODO(bug XXXXXXX): Consider strengthening this check to "A client MUST NOT
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// seek a match for a reference identifier of CN-ID if the certificate
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// contains a subjectAltName extension."
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//
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// TODO(bug XXXXXXX): Consider dropping support for IP addresses as
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// identifiers completely.
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bool hasAtLeastOneDNSNameOrIPAddressSAN = false;
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if (subjectAltName) {
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Reader altNames;
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rv = der::ExpectTagAndGetValueAtEnd(*subjectAltName, der::SEQUENCE,
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altNames);
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if (rv != Success) {
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return rv;
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}
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// do { ... } while(...) because subjectAltName isn't allowed to be empty.
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do {
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uint8_t tag;
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Input presentedID;
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rv = der::ReadTagAndGetValue(altNames, tag, presentedID);
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if (rv != Success) {
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return rv;
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}
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if (tag == static_cast<uint8_t>(referenceIDType)) {
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rv = MatchPresentedIDWithReferenceID(referenceIDType, presentedID,
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referenceID, foundMatch);
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if (rv != Success) {
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return rv;
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}
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if (foundMatch) {
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return Success;
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}
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}
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if (tag == static_cast<uint8_t>(GeneralNameType::dNSName) ||
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tag == static_cast<uint8_t>(GeneralNameType::iPAddress)) {
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hasAtLeastOneDNSNameOrIPAddressSAN = true;
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}
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} while (!altNames.AtEnd());
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}
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if (hasAtLeastOneDNSNameOrIPAddressSAN ||
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fallBackToCommonName != FallBackToCommonName::Yes) {
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return Success;
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}
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// Attempt to match the reference ID against the CN-ID, which we consider to
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// be the most-specific CN AVA in the subject field.
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//
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// https://tools.ietf.org/html/rfc6125#section-2.3.1 says:
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//
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// To reduce confusion, in this specification we avoid such terms and
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// instead use the terms provided under Section 1.8; in particular, we
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// do not use the term "(most specific) Common Name field in the subject
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// field" from [HTTP-TLS] and instead state that a CN-ID is a Relative
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// Distinguished Name (RDN) in the certificate subject containing one
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// and only one attribute-type-and-value pair of type Common Name (thus
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// removing the possibility that an RDN might contain multiple AVAs
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// (Attribute Value Assertions) of type CN, one of which could be
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// considered "most specific").
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//
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// https://tools.ietf.org/html/rfc6125#section-7.4 says:
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//
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// [...] Although it would be preferable to
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// forbid multiple CN-IDs entirely, there are several reasons at this
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// time why this specification states that they SHOULD NOT (instead of
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// MUST NOT) be included [...]
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//
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// Consequently, it is unclear what to do when there are multiple CNs in the
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// subject, regardless of whether there "SHOULD NOT" be.
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//
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// NSS's CERT_VerifyCertName mostly follows RFC2818 in this instance, which
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// says:
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//
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// If a subjectAltName extension of type dNSName is present, that MUST
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// be used as the identity. Otherwise, the (most specific) Common Name
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// field in the Subject field of the certificate MUST be used.
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//
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// [...]
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//
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// In some cases, the URI is specified as an IP address rather than a
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// hostname. In this case, the iPAddress subjectAltName must be present
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// in the certificate and must exactly match the IP in the URI.
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//
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// (The main difference from RFC2818 is that NSS's CERT_VerifyCertName also
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// matches IP addresses in the most-specific CN.)
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//
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// NSS's CERT_VerifyCertName finds the most specific CN via
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// CERT_GetCommoName, which uses CERT_GetLastNameElement. Note that many
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// NSS-based applications, including Gecko, also use CERT_GetCommonName. It
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// is likely that other, non-NSS-based, applications also expect only the
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// most specific CN to be matched against the reference ID.
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//
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// "A Layman's Guide to a Subset of ASN.1, BER, and DER" and other sources
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// agree that an RDNSequence is ordered from most significant (least
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// specific) to least significant (most specific), as do other references.
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//
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// However, Chromium appears to use the least-specific (first) CN instead of
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// the most-specific; see https://crbug.com/366957. Also, MSIE and some other
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// popular implementations apparently attempt to match the reference ID
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// against any/all CNs in the subject. Since we're trying to phase out the
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// use of CN-IDs, we intentionally avoid trying to match MSIE's more liberal
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// behavior.
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// Name ::= CHOICE { -- only one possibility for now --
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// rdnSequence RDNSequence }
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//
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// RDNSequence ::= SEQUENCE OF RelativeDistinguishedName
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//
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// RelativeDistinguishedName ::=
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// SET SIZE (1..MAX) OF AttributeTypeAndValue
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Reader subjectReader(subject);
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return der::NestedOf(subjectReader, der::SEQUENCE, der::SET,
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der::EmptyAllowed::Yes,
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bind(SearchWithinRDN, _1, referenceIDType,
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referenceID, ref(foundMatch)));
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}
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// RelativeDistinguishedName ::=
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// SET SIZE (1..MAX) OF AttributeTypeAndValue
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//
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// AttributeTypeAndValue ::= SEQUENCE {
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// type AttributeType,
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// value AttributeValue }
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Result
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SearchWithinRDN(Reader& rdn,
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GeneralNameType referenceIDType,
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Input referenceID,
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/*in/out*/ bool& foundMatch)
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{
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do {
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Result rv = der::Nested(rdn, der::SEQUENCE,
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bind(SearchWithinAVA, _1, referenceIDType,
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referenceID, ref(foundMatch)));
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if (rv != Success) {
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return rv;
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}
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} while (!rdn.AtEnd());
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return Success;
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}
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// AttributeTypeAndValue ::= SEQUENCE {
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// type AttributeType,
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// value AttributeValue }
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//
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// AttributeType ::= OBJECT IDENTIFIER
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//
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// AttributeValue ::= ANY -- DEFINED BY AttributeType
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//
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// DirectoryString ::= CHOICE {
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// teletexString TeletexString (SIZE (1..MAX)),
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// printableString PrintableString (SIZE (1..MAX)),
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// universalString UniversalString (SIZE (1..MAX)),
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// utf8String UTF8String (SIZE (1..MAX)),
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// bmpString BMPString (SIZE (1..MAX)) }
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Result
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SearchWithinAVA(Reader& rdn,
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GeneralNameType referenceIDType,
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Input referenceID,
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/*in/out*/ bool& foundMatch)
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{
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// id-at OBJECT IDENTIFIER ::= { joint-iso-ccitt(2) ds(5) 4 }
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// id-at-commonName AttributeType ::= { id-at 3 }
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// python DottedOIDToCode.py id-at-commonName 2.5.4.3
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static const uint8_t id_at_commonName[] = {
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0x55, 0x04, 0x03
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};
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// AttributeTypeAndValue ::= SEQUENCE {
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// type AttributeType,
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// value AttributeValue }
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//
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// AttributeType ::= OBJECT IDENTIFIER
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//
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// AttributeValue ::= ANY -- DEFINED BY AttributeType
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//
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// DirectoryString ::= CHOICE {
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// teletexString TeletexString (SIZE (1..MAX)),
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// printableString PrintableString (SIZE (1..MAX)),
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// universalString UniversalString (SIZE (1..MAX)),
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// utf8String UTF8String (SIZE (1..MAX)),
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// bmpString BMPString (SIZE (1..MAX)) }
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Reader type;
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Result rv = der::ExpectTagAndGetValue(rdn, der::OIDTag, type);
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if (rv != Success) {
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return rv;
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}
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// We're only interested in CN attributes.
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if (!type.MatchRest(id_at_commonName)) {
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rdn.SkipToEnd();
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return Success;
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}
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// We might have previously found a match. Now that we've found another CN,
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// we no longer consider that previous match to be a match, so "forget" about
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// it.
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foundMatch = false;
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uint8_t valueEncodingTag;
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Input presentedID;
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rv = der::ReadTagAndGetValue(rdn, valueEncodingTag, presentedID);
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if (rv != Success) {
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return rv;
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}
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// PrintableString is a subset of ASCII that contains all the characters
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// allowed in CN-IDs except '*'. Although '*' is illegal, there are many
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// real-world certificates that are encoded this way, so we accept it.
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//
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// In the case of UTF8String, we rely on the fact that in UTF-8 the octets in
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// a multi-byte encoding of a code point are always distinct from ASCII. Any
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// non-ASCII byte in a UTF-8 string causes us to fail to match. We make no
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// attempt to detect or report malformed UTF-8 (e.g. incomplete or overlong
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// encodings of code points, or encodings of invalid code points).
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//
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// TeletexString is supported as long as it does not contain any escape
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// sequences, which are not supported. We'll reject escape sequences as
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// invalid characters in names, which means we only accept strings that are
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// in the default character set, which is a superset of ASCII. Note that NSS
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// actually treats TeletexString as ISO-8859-1. Many certificates that have
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// wildcard CN-IDs (e.g. "*.example.com") use TeletexString because
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// PrintableString is defined to not allow '*' and because, at one point in
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// history, UTF8String was too new to use for compatibility reasons.
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//
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// UniversalString and BMPString are also deprecated, and they are a little
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// harder to support because they are not single-byte ASCII superset
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// encodings, so we don't bother.
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if (valueEncodingTag != der::PrintableString &&
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valueEncodingTag != der::UTF8String &&
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valueEncodingTag != der::TeletexString) {
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return Success;
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}
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switch (referenceIDType)
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{
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case GeneralNameType::dNSName:
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foundMatch = PresentedDNSIDMatchesReferenceDNSID(presentedID,
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referenceID);
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break;
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case GeneralNameType::iPAddress:
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{
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// We don't fall back to matching CN-IDs for IPv6 addresses, so we'll
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// never get here for an IPv6 address.
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assert(referenceID.GetLength() == 4);
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uint8_t ipv4[4];
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foundMatch = ParseIPv4Address(presentedID, ipv4) &&
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InputsAreEqual(Input(ipv4), referenceID);
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break;
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}
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default:
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return NotReached("unexpected referenceIDType in SearchWithinAVA",
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Result::FATAL_ERROR_INVALID_ARGS);
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}
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return Success;
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}
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Result
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MatchPresentedIDWithReferenceID(GeneralNameType nameType,
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Input presentedID,
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Input referenceID,
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/*out*/ bool& foundMatch)
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{
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foundMatch = false;
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switch (nameType) {
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case GeneralNameType::dNSName:
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foundMatch = PresentedDNSIDMatchesReferenceDNSID(presentedID,
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referenceID);
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break;
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case GeneralNameType::iPAddress:
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foundMatch = InputsAreEqual(presentedID, referenceID);
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break;
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default:
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return NotReached("Invalid nameType for SearchType::CheckName",
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Result::FATAL_ERROR_INVALID_ARGS);
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}
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return Success;
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}
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} // unnamed namespace
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// We do not distinguish between a syntactically-invalid presentedDNSID and one
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// that is syntactically valid but does not match referenceDNSID; in both
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// cases, the result is false.
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//
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// We assume that both presentedDNSID and referenceDNSID are encoded in such a
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// way that US-ASCII (7-bit) characters are encoded in one byte and no encoding
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// of a non-US-ASCII character contains a code point in the range 0-127. For
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// example, UTF-8 is OK but UTF-16 is not.
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//
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// RFC6125 says that a wildcard label may be of the form <x>*<y>.<DNSID>, where
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// <x> and/or <y> may be empty. However, NSS requires <y> to be empty, and we
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// follow NSS's stricter policy by accepting wildcards only of the form
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// <x>*.<DNSID>, where <x> may be empty.
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bool
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PresentedDNSIDMatchesReferenceDNSID(Input presentedDNSID, Input referenceDNSID)
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{
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if (!IsValidPresentedDNSID(presentedDNSID)) {
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return false;
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}
|
|
if (!IsValidReferenceDNSID(referenceDNSID)) {
|
|
return false;
|
|
}
|
|
|
|
Reader presented(presentedDNSID);
|
|
Reader reference(referenceDNSID);
|
|
bool isFirstPresentedByte = true;
|
|
do {
|
|
uint8_t presentedByte;
|
|
Result rv = presented.Read(presentedByte);
|
|
if (rv != Success) {
|
|
return false;
|
|
}
|
|
if (presentedByte == '*') {
|
|
// RFC 6125 is unclear about whether "www*.example.org" matches
|
|
// "www.example.org". The Chromium test suite has this test:
|
|
//
|
|
// { false, "w.bar.foo.com", "w*.bar.foo.com" },
|
|
//
|
|
// We agree with Chromium by forbidding "*" from expanding to the empty
|
|
// string.
|
|
do {
|
|
uint8_t referenceByte;
|
|
rv = reference.Read(referenceByte);
|
|
if (rv != Success) {
|
|
return false;
|
|
}
|
|
} while (!reference.Peek('.'));
|
|
|
|
// We also don't allow a non-IDN presented ID label to match an IDN
|
|
// reference ID label, except when the entire presented ID label is "*".
|
|
// This avoids confusion when matching a presented ID like
|
|
// "xn-*.example.org" against "xn--www.example.org" (which attempts to
|
|
// abuse the punycode syntax) or "www-*.example.org" against
|
|
// "xn--www--ep4c4a2kpf" (which makes sense to match, semantically, but
|
|
// no implementations actually do).
|
|
if (!isFirstPresentedByte && StartsWithIDNALabel(referenceDNSID)) {
|
|
return false;
|
|
}
|
|
} else {
|
|
// Allow an absolute presented DNS ID to match a relative reference DNS
|
|
// ID.
|
|
if (reference.AtEnd() && presented.AtEnd() && presentedByte == '.') {
|
|
return true;
|
|
}
|
|
|
|
uint8_t referenceByte;
|
|
rv = reference.Read(referenceByte);
|
|
if (rv != Success) {
|
|
return false;
|
|
}
|
|
if (LocaleInsensitveToLower(presentedByte) !=
|
|
LocaleInsensitveToLower(referenceByte)) {
|
|
return false;
|
|
}
|
|
}
|
|
isFirstPresentedByte = false;
|
|
} while (!presented.AtEnd());
|
|
|
|
// Allow a relative presented DNS ID to match an absolute reference DNS ID.
|
|
if (!reference.AtEnd()) {
|
|
uint8_t referenceByte;
|
|
Result rv = reference.Read(referenceByte);
|
|
if (rv != Success) {
|
|
return false;
|
|
}
|
|
if (referenceByte != '.') {
|
|
return false;
|
|
}
|
|
if (!reference.AtEnd()) {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
namespace {
|
|
|
|
// We avoid isdigit because it is locale-sensitive. See
|
|
// http://pubs.opengroup.org/onlinepubs/009695399/functions/tolower.html.
|
|
inline uint8_t
|
|
LocaleInsensitveToLower(uint8_t a)
|
|
{
|
|
if (a >= 'A' && a <= 'Z') { // unlikely
|
|
return static_cast<uint8_t>(
|
|
static_cast<uint8_t>(a - static_cast<uint8_t>('A')) +
|
|
static_cast<uint8_t>('a'));
|
|
}
|
|
return a;
|
|
}
|
|
|
|
bool
|
|
StartsWithIDNALabel(Input id)
|
|
{
|
|
static const uint8_t IDN_ALABEL_PREFIX[4] = { 'x', 'n', '-', '-' };
|
|
Reader input(id);
|
|
for (size_t i = 0; i < sizeof(IDN_ALABEL_PREFIX); ++i) {
|
|
uint8_t b;
|
|
if (input.Read(b) != Success) {
|
|
return false;
|
|
}
|
|
if (b != IDN_ALABEL_PREFIX[i]) {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
bool
|
|
ReadIPv4AddressComponent(Reader& input, bool lastComponent,
|
|
/*out*/ uint8_t& valueOut)
|
|
{
|
|
size_t length = 0;
|
|
unsigned int value = 0; // Must be larger than uint8_t.
|
|
|
|
for (;;) {
|
|
if (input.AtEnd() && lastComponent) {
|
|
break;
|
|
}
|
|
|
|
uint8_t b;
|
|
if (input.Read(b) != Success) {
|
|
return false;
|
|
}
|
|
|
|
if (b >= '0' && b <= '9') {
|
|
if (value == 0 && length > 0) {
|
|
return false; // Leading zeros are not allowed.
|
|
}
|
|
value = (value * 10) + (b - '0');
|
|
if (value > 255) {
|
|
return false; // Component's value is too large.
|
|
}
|
|
++length;
|
|
} else if (!lastComponent && b == '.') {
|
|
break;
|
|
} else {
|
|
return false; // Invalid character.
|
|
}
|
|
}
|
|
|
|
if (length == 0) {
|
|
return false; // empty components not allowed
|
|
}
|
|
|
|
valueOut = static_cast<uint8_t>(value);
|
|
return true;
|
|
}
|
|
|
|
} // unnamed namespace
|
|
|
|
bool
|
|
ParseIPv4Address(Input hostname, /*out*/ uint8_t (&out)[4])
|
|
{
|
|
Reader input(hostname);
|
|
return ReadIPv4AddressComponent(input, false, out[0]) &&
|
|
ReadIPv4AddressComponent(input, false, out[1]) &&
|
|
ReadIPv4AddressComponent(input, false, out[2]) &&
|
|
ReadIPv4AddressComponent(input, true, out[3]);
|
|
}
|
|
|
|
namespace {
|
|
|
|
bool
|
|
FinishIPv6Address(/*in/out*/ uint8_t (&address)[16], int numComponents,
|
|
int contractionIndex)
|
|
{
|
|
assert(numComponents >= 0);
|
|
assert(numComponents <= 8);
|
|
assert(contractionIndex >= -1);
|
|
assert(contractionIndex <= 8);
|
|
assert(contractionIndex <= numComponents);
|
|
if (!(numComponents >= 0 &&
|
|
numComponents <= 8 &&
|
|
contractionIndex >= -1 &&
|
|
contractionIndex <= 8 &&
|
|
contractionIndex <= numComponents)) {
|
|
return false;
|
|
}
|
|
|
|
if (contractionIndex == -1) {
|
|
// no contraction
|
|
return numComponents == 8;
|
|
}
|
|
|
|
if (numComponents >= 8) {
|
|
return false; // no room left to expand the contraction.
|
|
}
|
|
|
|
// Shift components that occur after the contraction over.
|
|
int componentsToMove = numComponents - contractionIndex;
|
|
memmove(address + (2u * (8 - componentsToMove)),
|
|
address + (2u * contractionIndex),
|
|
componentsToMove * 2u);
|
|
// Fill in the contracted area with zeros.
|
|
memset(address + (2u * contractionIndex), 0u,
|
|
(8u - numComponents) * 2u);
|
|
|
|
return true;
|
|
}
|
|
|
|
} // unnamed namespace
|
|
|
|
|
|
bool
|
|
ParseIPv6Address(Input hostname, /*out*/ uint8_t (&out)[16])
|
|
{
|
|
Reader input(hostname);
|
|
|
|
int currentComponentIndex = 0;
|
|
int contractionIndex = -1;
|
|
|
|
if (input.Peek(':')) {
|
|
// A valid input can only start with ':' if there is a contraction at the
|
|
// beginning.
|
|
uint8_t b;
|
|
if (input.Read(b) != Success || b != ':') {
|
|
assert(false);
|
|
return false;
|
|
}
|
|
if (input.Read(b) != Success) {
|
|
return false;
|
|
}
|
|
if (b != ':') {
|
|
return false;
|
|
}
|
|
contractionIndex = 0;
|
|
}
|
|
|
|
for (;;) {
|
|
// If we encounter a '.' then we'll have to backtrack to parse the input
|
|
// from startOfComponent to the end of the input as an IPv4 address.
|
|
Reader::Mark startOfComponent(input.GetMark());
|
|
uint16_t componentValue = 0;
|
|
size_t componentLength = 0;
|
|
while (!input.AtEnd() && !input.Peek(':')) {
|
|
uint8_t value;
|
|
uint8_t b;
|
|
if (input.Read(b) != Success) {
|
|
assert(false);
|
|
return false;
|
|
}
|
|
switch (b) {
|
|
case '0': case '1': case '2': case '3': case '4':
|
|
case '5': case '6': case '7': case '8': case '9':
|
|
value = static_cast<uint8_t>(b - static_cast<uint8_t>('0'));
|
|
break;
|
|
case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
|
|
value = static_cast<uint8_t>(b - static_cast<uint8_t>('a') +
|
|
UINT8_C(10));
|
|
break;
|
|
case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
|
|
value = static_cast<uint8_t>(b - static_cast<uint8_t>('A') +
|
|
UINT8_C(10));
|
|
break;
|
|
case '.':
|
|
{
|
|
// A dot indicates we hit a IPv4-syntax component. Backtrack, parsing
|
|
// the input from startOfComponent to the end of the input as an IPv4
|
|
// address, and then combine it with the other components.
|
|
|
|
if (currentComponentIndex > 6) {
|
|
return false; // Too many components before the IPv4 component
|
|
}
|
|
|
|
input.SkipToEnd();
|
|
Input ipv4Component;
|
|
if (input.GetInput(startOfComponent, ipv4Component) != Success) {
|
|
return false;
|
|
}
|
|
uint8_t (*ipv4)[4] =
|
|
reinterpret_cast<uint8_t(*)[4]>(&out[2 * currentComponentIndex]);
|
|
if (!ParseIPv4Address(ipv4Component, *ipv4)) {
|
|
return false;
|
|
}
|
|
assert(input.AtEnd());
|
|
currentComponentIndex += 2;
|
|
|
|
return FinishIPv6Address(out, currentComponentIndex,
|
|
contractionIndex);
|
|
}
|
|
default:
|
|
return false;
|
|
}
|
|
if (componentLength >= 4) {
|
|
// component too long
|
|
return false;
|
|
}
|
|
++componentLength;
|
|
componentValue = (componentValue * 0x10u) + value;
|
|
}
|
|
|
|
if (currentComponentIndex >= 8) {
|
|
return false; // too many components
|
|
}
|
|
|
|
if (componentLength == 0) {
|
|
if (input.AtEnd() && currentComponentIndex == contractionIndex) {
|
|
if (contractionIndex == 0) {
|
|
// don't accept "::"
|
|
return false;
|
|
}
|
|
return FinishIPv6Address(out, currentComponentIndex,
|
|
contractionIndex);
|
|
}
|
|
return false;
|
|
}
|
|
|
|
out[2 * currentComponentIndex] =
|
|
static_cast<uint8_t>(componentValue / 0x100);
|
|
out[(2 * currentComponentIndex) + 1] =
|
|
static_cast<uint8_t>(componentValue % 0x100);
|
|
|
|
++currentComponentIndex;
|
|
|
|
if (input.AtEnd()) {
|
|
return FinishIPv6Address(out, currentComponentIndex,
|
|
contractionIndex);
|
|
}
|
|
|
|
uint8_t b;
|
|
if (input.Read(b) != Success || b != ':') {
|
|
assert(false);
|
|
return false;
|
|
}
|
|
|
|
if (input.Peek(':')) {
|
|
// Contraction
|
|
if (contractionIndex != -1) {
|
|
return false; // multiple contractions are not allowed.
|
|
}
|
|
uint8_t b;
|
|
if (input.Read(b) != Success || b != ':') {
|
|
assert(false);
|
|
return false;
|
|
}
|
|
contractionIndex = currentComponentIndex;
|
|
if (input.AtEnd()) {
|
|
// "::" at the end of the input.
|
|
return FinishIPv6Address(out, currentComponentIndex,
|
|
contractionIndex);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
bool
|
|
IsValidReferenceDNSID(Input hostname)
|
|
{
|
|
return IsValidDNSID(hostname, ValidDNSIDMatchType::ReferenceID);
|
|
}
|
|
|
|
bool
|
|
IsValidPresentedDNSID(Input hostname)
|
|
{
|
|
return IsValidDNSID(hostname, ValidDNSIDMatchType::PresentedID);
|
|
}
|
|
|
|
namespace {
|
|
|
|
bool
|
|
IsValidDNSID(Input hostname, ValidDNSIDMatchType matchType)
|
|
{
|
|
if (hostname.GetLength() > 253) {
|
|
return false;
|
|
}
|
|
|
|
Reader input(hostname);
|
|
|
|
bool allowWildcard = matchType == ValidDNSIDMatchType::PresentedID;
|
|
bool isWildcard = false;
|
|
size_t dotCount = 0;
|
|
|
|
size_t labelLength = 0;
|
|
bool labelIsAllNumeric = false;
|
|
bool labelIsWildcard = false;
|
|
bool labelEndsWithHyphen = false;
|
|
|
|
do {
|
|
static const size_t MAX_LABEL_LENGTH = 63;
|
|
|
|
uint8_t b;
|
|
if (input.Read(b) != Success) {
|
|
return false;
|
|
}
|
|
if (labelIsWildcard) {
|
|
// Like NSS, be stricter than RFC6125 requires by insisting that the
|
|
// "*" must be the last character in the label. This also prevents
|
|
// multiple "*" in the label.
|
|
if (b != '.') {
|
|
return false;
|
|
}
|
|
}
|
|
switch (b) {
|
|
case '-':
|
|
if (labelLength == 0) {
|
|
return false; // Labels must not start with a hyphen.
|
|
}
|
|
labelIsAllNumeric = false;
|
|
labelEndsWithHyphen = true;
|
|
++labelLength;
|
|
if (labelLength > MAX_LABEL_LENGTH) {
|
|
return false;
|
|
}
|
|
break;
|
|
|
|
// We avoid isdigit because it is locale-sensitive. See
|
|
// http://pubs.opengroup.org/onlinepubs/009695399/functions/isdigit.html
|
|
case '0': case '5':
|
|
case '1': case '6':
|
|
case '2': case '7':
|
|
case '3': case '8':
|
|
case '4': case '9':
|
|
if (labelLength == 0) {
|
|
labelIsAllNumeric = true;
|
|
}
|
|
labelEndsWithHyphen = false;
|
|
++labelLength;
|
|
if (labelLength > MAX_LABEL_LENGTH) {
|
|
return false;
|
|
}
|
|
break;
|
|
|
|
// We avoid using islower/isupper/tolower/toupper or similar things, to
|
|
// avoid any possibility of this code being locale-sensitive. See
|
|
// http://pubs.opengroup.org/onlinepubs/009695399/functions/isupper.html
|
|
case 'a': case 'A': case 'n': case 'N':
|
|
case 'b': case 'B': case 'o': case 'O':
|
|
case 'c': case 'C': case 'p': case 'P':
|
|
case 'd': case 'D': case 'q': case 'Q':
|
|
case 'e': case 'E': case 'r': case 'R':
|
|
case 'f': case 'F': case 's': case 'S':
|
|
case 'g': case 'G': case 't': case 'T':
|
|
case 'h': case 'H': case 'u': case 'U':
|
|
case 'i': case 'I': case 'v': case 'V':
|
|
case 'j': case 'J': case 'w': case 'W':
|
|
case 'k': case 'K': case 'x': case 'X':
|
|
case 'l': case 'L': case 'y': case 'Y':
|
|
case 'm': case 'M': case 'z': case 'Z':
|
|
labelIsAllNumeric = false;
|
|
labelEndsWithHyphen = false;
|
|
++labelLength;
|
|
if (labelLength > MAX_LABEL_LENGTH) {
|
|
return false;
|
|
}
|
|
break;
|
|
|
|
case '*':
|
|
if (!allowWildcard) {
|
|
return false;
|
|
}
|
|
labelIsWildcard = true;
|
|
isWildcard = true;
|
|
labelIsAllNumeric = false;
|
|
labelEndsWithHyphen = false;
|
|
++labelLength;
|
|
if (labelLength > MAX_LABEL_LENGTH) {
|
|
return false;
|
|
}
|
|
break;
|
|
|
|
case '.':
|
|
++dotCount;
|
|
if (labelLength == 0) {
|
|
return false;
|
|
}
|
|
if (labelEndsWithHyphen) {
|
|
return false; // Labels must not end with a hyphen.
|
|
}
|
|
allowWildcard = false; // only allowed in the first label.
|
|
labelIsWildcard = false;
|
|
labelLength = 0;
|
|
break;
|
|
|
|
default:
|
|
return false; // Invalid character.
|
|
}
|
|
} while (!input.AtEnd());
|
|
|
|
if (labelEndsWithHyphen) {
|
|
return false; // Labels must not end with a hyphen.
|
|
}
|
|
|
|
if (labelIsAllNumeric) {
|
|
return false; // Last label must not be all numeric.
|
|
}
|
|
|
|
if (isWildcard) {
|
|
// If the DNS ID ends with a dot, the last dot signifies an absolute ID.
|
|
size_t labelCount = (labelLength == 0) ? dotCount : (dotCount + 1);
|
|
|
|
// Like NSS, require at least two labels to follow the wildcard label.
|
|
//
|
|
// TODO(bug XXXXXXX): Allow the TrustDomain to control this on a
|
|
// per-eTLD+1 basis, similar to Chromium. Even then, it might be better to
|
|
// still enforce that there are at least two labels after the wildcard.
|
|
if (labelCount < 3) {
|
|
return false;
|
|
}
|
|
// XXX: RFC6125 says that we shouldn't accept wildcards within an IDN
|
|
// A-Label. The consequence of this is that we effectively discriminate
|
|
// against users of languages that cannot be encoded with ASCII.
|
|
if (StartsWithIDNALabel(hostname)) {
|
|
return false;
|
|
}
|
|
|
|
// TODO(bug XXXXXXX): Wildcards are not allowed for EV certificates.
|
|
// Provide an option to indicate whether wildcards should be matched, for
|
|
// the purpose of helping the application enforce this.
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
} // unnamed namespace
|
|
|
|
} } // namespace mozilla::pkix
|