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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This code is made available to you under your choice of the following sets
* of licensing terms:
*/
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
*/
/* Copyright 2013 Mozilla Contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef mozilla_pkix_pkixutil_h
#define mozilla_pkix_pkixutil_h
#include "mozpkix/pkixder.h"
namespace mozilla {
namespace pkix {
// During path building and verification, we build a linked list of BackCerts
// from the current cert toward the end-entity certificate. The linked list
// is used to verify properties that aren't local to the current certificate
// and/or the direct link between the current certificate and its issuer,
// such as name constraints.
//
// Each BackCert contains pointers to all the given certificate's extensions
// so that we can parse the extension block once and then process the
// extensions in an order that may be different than they appear in the cert.
class BackCert final {
public:
// certDER and childCert must be valid for the lifetime of BackCert.
BackCert(Input aCertDER, EndEntityOrCA aEndEntityOrCA,
const BackCert* aChildCert)
: der(aCertDER),
endEntityOrCA(aEndEntityOrCA),
childCert(aChildCert),
version(der::Version::Uninitialized) {}
Result Init();
const Input GetDER() const { return der; }
const der::SignedDataWithSignature& GetSignedData() const {
return signedData;
}
der::Version GetVersion() const { return version; }
const Input GetSerialNumber() const { return serialNumber; }
const Input GetSignature() const { return signature; }
const Input GetIssuer() const { return issuer; }
// XXX: "validity" is a horrible name for the structure that holds
// notBefore & notAfter, but that is the name used in RFC 5280 and we use the
// RFC 5280 names for everything.
const Input GetValidity() const { return validity; }
const Input GetSubject() const { return subject; }
const Input GetSubjectPublicKeyInfo() const { return subjectPublicKeyInfo; }
const Input* GetAuthorityInfoAccess() const {
return MaybeInput(authorityInfoAccess);
}
const Input* GetBasicConstraints() const {
return MaybeInput(basicConstraints);
}
const Input* GetCertificatePolicies() const {
return MaybeInput(certificatePolicies);
}
const Input* GetExtKeyUsage() const { return MaybeInput(extKeyUsage); }
const Input* GetKeyUsage() const { return MaybeInput(keyUsage); }
const Input* GetInhibitAnyPolicy() const {
return MaybeInput(inhibitAnyPolicy);
}
const Input* GetNameConstraints() const {
return MaybeInput(nameConstraints);
}
const Input* GetSubjectAltName() const { return MaybeInput(subjectAltName); }
const Input* GetRequiredTLSFeatures() const {
return MaybeInput(requiredTLSFeatures);
}
const Input* GetSignedCertificateTimestamps() const {
return MaybeInput(signedCertificateTimestamps);
}
private:
const Input der;
public:
const EndEntityOrCA endEntityOrCA;
BackCert const* const childCert;
private:
// When parsing certificates in BackCert::Init, we don't accept empty
// extensions. Consequently, we don't have to store a distinction between
// empty extensions and extensions that weren't included. However, when
// *processing* extensions, we distinguish between whether an extension was
// included or not based on whetehr the GetXXX function for the extension
// returns nullptr.
static inline const Input* MaybeInput(const Input& item) {
return item.GetLength() > 0 ? &item : nullptr;
}
der::SignedDataWithSignature signedData;
der::Version version;
Input serialNumber;
Input signature;
Input issuer;
// XXX: "validity" is a horrible name for the structure that holds
// notBefore & notAfter, but that is the name used in RFC 5280 and we use the
// RFC 5280 names for everything.
Input validity;
Input subject;
Input subjectPublicKeyInfo;
Input authorityInfoAccess;
Input basicConstraints;
Input certificatePolicies;
Input extKeyUsage;
Input inhibitAnyPolicy;
Input keyUsage;
Input nameConstraints;
Input subjectAltName;
Input criticalNetscapeCertificateType;
Input requiredTLSFeatures;
Input signedCertificateTimestamps; // RFC 6962 (Certificate Transparency)
Result RememberExtension(Reader& extnID, Input extnValue, bool critical,
/*out*/ bool& understood);
BackCert(const BackCert&) = delete;
void operator=(const BackCert&) = delete;
};
class NonOwningDERArray final : public DERArray {
public:
NonOwningDERArray() : numItems(0) {
// we don't need to initialize the items array because we always check
// numItems before accessing i.
}
size_t GetLength() const override { return numItems; }
const Input* GetDER(size_t i) const override {
return i < numItems ? &items[i] : nullptr;
}
Result Append(Input der) {
if (numItems >= MAX_LENGTH) {
return Result::FATAL_ERROR_INVALID_ARGS;
}
Result rv = items[numItems].Init(der); // structure assignment
if (rv != Success) {
return rv;
}
++numItems;
return Success;
}
// Public so we can static_assert on this. Keep in sync with MAX_SUBCA_COUNT.
static const size_t MAX_LENGTH = 8;
private:
Input items[MAX_LENGTH]; // avoids any heap allocations
size_t numItems;
NonOwningDERArray(const NonOwningDERArray&) = delete;
void operator=(const NonOwningDERArray&) = delete;
};
// Extracts the SignedCertificateTimestampList structure which is encoded as an
// OCTET STRING within the X.509v3 / OCSP extensions (see RFC 6962 section 3.3).
Result ExtractSignedCertificateTimestampListFromExtension(Input extnValue,
Input& sctList);
inline unsigned int DaysBeforeYear(unsigned int year) {
assert(year <= 9999);
return ((year - 1u) * 365u) +
((year - 1u) / 4u) // leap years are every 4 years,
- ((year - 1u) / 100u) // except years divisible by 100,
+ ((year - 1u) / 400u); // except years divisible by 400.
}
static const size_t MAX_DIGEST_SIZE_IN_BYTES = 512 / 8; // sha-512
Result VerifySignedData(TrustDomain& trustDomain,
const der::SignedDataWithSignature& signedData,
Input signerSubjectPublicKeyInfo);
// Extracts the key parameters from |subjectPublicKeyInfo|, invoking
// the relevant methods of |trustDomain|.
Result CheckSubjectPublicKeyInfo(Input subjectPublicKeyInfo,
TrustDomain& trustDomain,
EndEntityOrCA endEntityOrCA);
// In a switch over an enum, sometimes some compilers are not satisfied that
// all control flow paths have been considered unless there is a default case.
// However, in our code, such a default case is almost always unreachable dead
// code. That can be particularly problematic when the compiler wants the code
// to choose a value, such as a return value, for the default case, but there's
// no appropriate "impossible case" value to choose.
//
// MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM accounts for this. Example:
//
// // In xy.cpp
// #include "xt.h"
//
// enum class XY { X, Y };
//
// int func(XY xy) {
// switch (xy) {
// case XY::X: return 1;
// case XY::Y; return 2;
// MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM
// }
// }
#if defined(__clang__)
// Clang will warn if not all cases are covered (-Wswitch-enum) AND it will
// warn if a switch statement that covers every enum label has a default case
// (-W-covered-switch-default). Versions prior to 3.5 warned about unreachable
// code in such default cases (-Wunreachable-code) even when
// -W-covered-switch-default was disabled, but that changed in Clang 3.5.
#define MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM // empty
#elif defined(__GNUC__)
// GCC will warn if not all cases are covered (-Wswitch-enum). It does not
// assume that the default case is unreachable.
#define MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM \
default: \
assert(false); \
__builtin_unreachable();
#elif defined(_MSC_VER)
// MSVC will warn if not all cases are covered (C4061, level 4). It does not
// assume that the default case is unreachable.
#define MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM \
default: \
assert(false); \
__assume(0);
#else
#error Unsupported compiler for MOZILLA_PKIX_UNREACHABLE_DEFAULT.
#endif
inline size_t DigestAlgorithmToSizeInBytes(DigestAlgorithm digestAlgorithm) {
switch (digestAlgorithm) {
case DigestAlgorithm::sha1:
return 160 / 8;
case DigestAlgorithm::sha256:
return 256 / 8;
case DigestAlgorithm::sha384:
return 384 / 8;
case DigestAlgorithm::sha512:
return 512 / 8;
MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM
}
}
} // namespace pkix
} // namespace mozilla
#endif // mozilla_pkix_pkixutil_h