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Diffstat (limited to 'security/pkix/lib/pkixder.h')
| -rw-r--r-- | security/pkix/lib/pkixder.h | 565 |
1 files changed, 565 insertions, 0 deletions
diff --git a/security/pkix/lib/pkixder.h b/security/pkix/lib/pkixder.h new file mode 100644 index 000000000..a17114bcb --- /dev/null +++ b/security/pkix/lib/pkixder.h @@ -0,0 +1,565 @@ +/* -*- 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 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + */ +/* 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 + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * 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_pkixder_h +#define mozilla_pkix_pkixder_h + +// Expect* functions advance the input mark and return Success if the input +// matches the given criteria; they fail with the input mark in an undefined +// state if the input does not match the criteria. +// +// Match* functions advance the input mark and return true if the input matches +// the given criteria; they return false without changing the input mark if the +// input does not match the criteria. +// +// Skip* functions unconditionally advance the input mark and return Success if +// they are able to do so; otherwise they fail with the input mark in an +// undefined state. + +#include "pkix/Input.h" +#include "pkix/pkixtypes.h" + +namespace mozilla { namespace pkix { namespace der { + +enum Class : uint8_t +{ + UNIVERSAL = 0 << 6, +// APPLICATION = 1 << 6, // unused + CONTEXT_SPECIFIC = 2 << 6, +// PRIVATE = 3 << 6 // unused +}; + +enum Constructed +{ + CONSTRUCTED = 1 << 5 +}; + +enum Tag : uint8_t +{ + BOOLEAN = UNIVERSAL | 0x01, + INTEGER = UNIVERSAL | 0x02, + BIT_STRING = UNIVERSAL | 0x03, + OCTET_STRING = UNIVERSAL | 0x04, + NULLTag = UNIVERSAL | 0x05, + OIDTag = UNIVERSAL | 0x06, + ENUMERATED = UNIVERSAL | 0x0a, + UTF8String = UNIVERSAL | 0x0c, + SEQUENCE = UNIVERSAL | CONSTRUCTED | 0x10, // 0x30 + SET = UNIVERSAL | CONSTRUCTED | 0x11, // 0x31 + PrintableString = UNIVERSAL | 0x13, + TeletexString = UNIVERSAL | 0x14, + IA5String = UNIVERSAL | 0x16, + UTCTime = UNIVERSAL | 0x17, + GENERALIZED_TIME = UNIVERSAL | 0x18, +}; + +enum class EmptyAllowed { No = 0, Yes = 1 }; + +Result ReadTagAndGetValue(Reader& input, /*out*/ uint8_t& tag, + /*out*/ Input& value); +Result End(Reader& input); + +inline Result +ExpectTagAndGetValue(Reader& input, uint8_t tag, /*out*/ Input& value) +{ + uint8_t actualTag; + Result rv = ReadTagAndGetValue(input, actualTag, value); + if (rv != Success) { + return rv; + } + if (tag != actualTag) { + return Result::ERROR_BAD_DER; + } + return Success; +} + +inline Result +ExpectTagAndGetValue(Reader& input, uint8_t tag, /*out*/ Reader& value) +{ + Input valueInput; + Result rv = ExpectTagAndGetValue(input, tag, valueInput); + if (rv != Success) { + return rv; + } + return value.Init(valueInput); +} + +inline Result +ExpectTagAndEmptyValue(Reader& input, uint8_t tag) +{ + Reader value; + Result rv = ExpectTagAndGetValue(input, tag, value); + if (rv != Success) { + return rv; + } + return End(value); +} + +inline Result +ExpectTagAndSkipValue(Reader& input, uint8_t tag) +{ + Input ignoredValue; + return ExpectTagAndGetValue(input, tag, ignoredValue); +} + +// Like ExpectTagAndGetValue, except the output Input will contain the +// encoded tag and length along with the value. +inline Result +ExpectTagAndGetTLV(Reader& input, uint8_t tag, /*out*/ Input& tlv) +{ + Reader::Mark mark(input.GetMark()); + Result rv = ExpectTagAndSkipValue(input, tag); + if (rv != Success) { + return rv; + } + return input.GetInput(mark, tlv); +} + +inline Result +End(Reader& input) +{ + if (!input.AtEnd()) { + return Result::ERROR_BAD_DER; + } + + return Success; +} + +template <typename Decoder> +inline Result +Nested(Reader& input, uint8_t tag, Decoder decoder) +{ + Reader nested; + Result rv = ExpectTagAndGetValue(input, tag, nested); + if (rv != Success) { + return rv; + } + rv = decoder(nested); + if (rv != Success) { + return rv; + } + return End(nested); +} + +template <typename Decoder> +inline Result +Nested(Reader& input, uint8_t outerTag, uint8_t innerTag, Decoder decoder) +{ + Reader nestedInput; + Result rv = ExpectTagAndGetValue(input, outerTag, nestedInput); + if (rv != Success) { + return rv; + } + rv = Nested(nestedInput, innerTag, decoder); + if (rv != Success) { + return rv; + } + return End(nestedInput); +} + +// This can be used to decode constructs like this: +// +// ... +// foos SEQUENCE OF Foo, +// ... +// Foo ::= SEQUENCE { +// } +// +// using code like this: +// +// Result Foo(Reader& r) { /*...*/ } +// +// rv = der::NestedOf(input, der::SEQEUENCE, der::SEQUENCE, Foo); +// +// or: +// +// Result Bar(Reader& r, int value) { /*...*/ } +// +// int value = /*...*/; +// +// rv = der::NestedOf(input, der::SEQUENCE, [value](Reader& r) { +// return Bar(r, value); +// }); +// +// In these examples the function will get called once for each element of +// foos. +// +template <typename Decoder> +inline Result +NestedOf(Reader& input, uint8_t outerTag, uint8_t innerTag, + EmptyAllowed mayBeEmpty, Decoder decoder) +{ + Reader inner; + Result rv = ExpectTagAndGetValue(input, outerTag, inner); + if (rv != Success) { + return rv; + } + + if (inner.AtEnd()) { + if (mayBeEmpty != EmptyAllowed::Yes) { + return Result::ERROR_BAD_DER; + } + return Success; + } + + do { + rv = Nested(inner, innerTag, decoder); + if (rv != Success) { + return rv; + } + } while (!inner.AtEnd()); + + return Success; +} + +// Often, a function will need to decode an Input or Reader that contains +// DER-encoded data wrapped in a SEQUENCE (or similar) with nothing after it. +// This function reduces the boilerplate necessary for stripping the outermost +// SEQUENCE (or similar) and ensuring that nothing follows it. +inline Result +ExpectTagAndGetValueAtEnd(Reader& outer, uint8_t expectedTag, + /*out*/ Reader& inner) +{ + Result rv = der::ExpectTagAndGetValue(outer, expectedTag, inner); + if (rv != Success) { + return rv; + } + return der::End(outer); +} + +// Similar to the above, but takes an Input instead of a Reader&. +inline Result +ExpectTagAndGetValueAtEnd(Input outer, uint8_t expectedTag, + /*out*/ Reader& inner) +{ + Reader outerReader(outer); + return ExpectTagAndGetValueAtEnd(outerReader, expectedTag, inner); +} + +// Universal types + +namespace internal { + +enum class IntegralValueRestriction +{ + NoRestriction, + MustBePositive, + MustBe0To127, +}; + +Result IntegralBytes(Reader& input, uint8_t tag, + IntegralValueRestriction valueRestriction, + /*out*/ Input& value, + /*optional out*/ Input::size_type* significantBytes = nullptr); + +// This parser will only parse values between 0..127. If this range is +// increased then callers will need to be changed. +Result IntegralValue(Reader& input, uint8_t tag, /*out*/ uint8_t& value); + +} // namespace internal + +Result +BitStringWithNoUnusedBits(Reader& input, /*out*/ Input& value); + +inline Result +Boolean(Reader& input, /*out*/ bool& value) +{ + Reader valueReader; + Result rv = ExpectTagAndGetValue(input, BOOLEAN, valueReader); + if (rv != Success) { + return rv; + } + + uint8_t intValue; + rv = valueReader.Read(intValue); + if (rv != Success) { + return rv; + } + rv = End(valueReader); + if (rv != Success) { + return rv; + } + switch (intValue) { + case 0: value = false; return Success; + case 0xFF: value = true; return Success; + default: + return Result::ERROR_BAD_DER; + } +} + +// This is for BOOLEAN DEFAULT FALSE. +// The standard stipulates that "The encoding of a set value or sequence value +// shall not include an encoding for any component value which is equal to its +// default value." However, it appears to be common that other libraries +// incorrectly include the value of a BOOLEAN even when it's equal to the +// default value, so we allow invalid explicit encodings here. +inline Result +OptionalBoolean(Reader& input, /*out*/ bool& value) +{ + value = false; + if (input.Peek(BOOLEAN)) { + Result rv = Boolean(input, value); + if (rv != Success) { + return rv; + } + } + return Success; +} + +// This parser will only parse values between 0..127. If this range is +// increased then callers will need to be changed. +inline Result +Enumerated(Reader& input, uint8_t& value) +{ + return internal::IntegralValue(input, ENUMERATED | 0, value); +} + +namespace internal { + +// internal::TimeChoice implements the shared functionality of GeneralizedTime +// and TimeChoice. tag must be either UTCTime or GENERALIZED_TIME. +// +// Only times from 1970-01-01-00:00:00 onward are accepted, in order to +// eliminate the chance for complications in converting times to traditional +// time formats that start at 1970. +Result TimeChoice(Reader& input, uint8_t tag, /*out*/ Time& time); + +} // namespace internal + +// Only times from 1970-01-01-00:00:00 onward are accepted, in order to +// eliminate the chance for complications in converting times to traditional +// time formats that start at 1970. +inline Result +GeneralizedTime(Reader& input, /*out*/ Time& time) +{ + return internal::TimeChoice(input, GENERALIZED_TIME, time); +} + +// Only times from 1970-01-01-00:00:00 onward are accepted, in order to +// eliminate the chance for complications in converting times to traditional +// time formats that start at 1970. +inline Result +TimeChoice(Reader& input, /*out*/ Time& time) +{ + uint8_t expectedTag = input.Peek(UTCTime) ? UTCTime : GENERALIZED_TIME; + return internal::TimeChoice(input, expectedTag, time); +} + +// Parse a DER integer value into value. Empty values, negative values, and +// zero are rejected. If significantBytes is not null, then it will be set to +// the number of significant bytes in the value (the length of the value, less +// the length of any leading padding), which is useful for key size checks. +inline Result +PositiveInteger(Reader& input, /*out*/ Input& value, + /*optional out*/ Input::size_type* significantBytes = nullptr) +{ + return internal::IntegralBytes( + input, INTEGER, internal::IntegralValueRestriction::MustBePositive, + value, significantBytes); +} + +// This parser will only parse values between 0..127. If this range is +// increased then callers will need to be changed. +inline Result +Integer(Reader& input, /*out*/ uint8_t& value) +{ + return internal::IntegralValue(input, INTEGER, value); +} + +// This parser will only parse values between 0..127. If this range is +// increased then callers will need to be changed. The default value must be +// -1; defaultValue is only a parameter to make it clear in the calling code +// what the default value is. +inline Result +OptionalInteger(Reader& input, long defaultValue, /*out*/ long& value) +{ + // If we need to support a different default value in the future, we need to + // test that parsedValue != defaultValue. + if (defaultValue != -1) { + return Result::FATAL_ERROR_INVALID_ARGS; + } + + if (!input.Peek(INTEGER)) { + value = defaultValue; + return Success; + } + + uint8_t parsedValue; + Result rv = Integer(input, parsedValue); + if (rv != Success) { + return rv; + } + value = parsedValue; + return Success; +} + +inline Result +Null(Reader& input) +{ + return ExpectTagAndEmptyValue(input, NULLTag); +} + +template <uint8_t Len> +Result +OID(Reader& input, const uint8_t (&expectedOid)[Len]) +{ + Reader value; + Result rv = ExpectTagAndGetValue(input, OIDTag, value); + if (rv != Success) { + return rv; + } + if (!value.MatchRest(expectedOid)) { + return Result::ERROR_BAD_DER; + } + return Success; +} + +// PKI-specific types + +inline Result +CertificateSerialNumber(Reader& input, /*out*/ Input& value) +{ + // http://tools.ietf.org/html/rfc5280#section-4.1.2.2: + // + // * "The serial number MUST be a positive integer assigned by the CA to + // each certificate." + // * "Certificate users MUST be able to handle serialNumber values up to 20 + // octets. Conforming CAs MUST NOT use serialNumber values longer than 20 + // octets." + // * "Note: Non-conforming CAs may issue certificates with serial numbers + // that are negative or zero. Certificate users SHOULD be prepared to + // gracefully handle such certificates." + return internal::IntegralBytes( + input, INTEGER, internal::IntegralValueRestriction::NoRestriction, + value); +} + +// x.509 and OCSP both use this same version numbering scheme, though OCSP +// only supports v1. +enum class Version { v1 = 0, v2 = 1, v3 = 2, v4 = 3 }; + +// X.509 Certificate and OCSP ResponseData both use +// "[0] EXPLICIT Version DEFAULT v1". Although an explicit encoding of v1 is +// illegal, we support it because some real-world OCSP responses explicitly +// encode it. +Result OptionalVersion(Reader& input, /*out*/ Version& version); + +template <typename ExtensionHandler> +inline Result +OptionalExtensions(Reader& input, uint8_t tag, + ExtensionHandler extensionHandler) +{ + if (!input.Peek(tag)) { + return Success; + } + + return Nested(input, tag, [extensionHandler](Reader& tagged) { + // Extensions ::= SEQUENCE SIZE (1..MAX) OF Extension + // + // TODO(bug 997994): According to the specification, there should never be + // an empty sequence of extensions but we've found OCSP responses that have + // that (see bug 991898). + return NestedOf(tagged, SEQUENCE, SEQUENCE, EmptyAllowed::Yes, + [extensionHandler](Reader& extension) -> Result { + // Extension ::= SEQUENCE { + // extnID OBJECT IDENTIFIER, + // critical BOOLEAN DEFAULT FALSE, + // extnValue OCTET STRING + // } + Reader extnID; + Result rv = ExpectTagAndGetValue(extension, OIDTag, extnID); + if (rv != Success) { + return rv; + } + bool critical; + rv = OptionalBoolean(extension, critical); + if (rv != Success) { + return rv; + } + Input extnValue; + rv = ExpectTagAndGetValue(extension, OCTET_STRING, extnValue); + if (rv != Success) { + return rv; + } + bool understood = false; + rv = extensionHandler(extnID, extnValue, critical, understood); + if (rv != Success) { + return rv; + } + if (critical && !understood) { + return Result::ERROR_UNKNOWN_CRITICAL_EXTENSION; + } + return Success; + }); + }); +} + +Result DigestAlgorithmIdentifier(Reader& input, + /*out*/ DigestAlgorithm& algorithm); + +enum class PublicKeyAlgorithm +{ + RSA_PKCS1, + ECDSA, +}; + +Result SignatureAlgorithmIdentifierValue( + Reader& input, + /*out*/ PublicKeyAlgorithm& publicKeyAlgorithm, + /*out*/ DigestAlgorithm& digestAlgorithm); + +struct SignedDataWithSignature final +{ +public: + Input data; + Input algorithm; + Input signature; + + void operator=(const SignedDataWithSignature&) = delete; +}; + +// Parses a SEQUENCE into tbs and then parses an AlgorithmIdentifier followed +// by a BIT STRING into signedData. This handles the commonality between +// parsing the signed/signature fields of certificates and OCSP responses. In +// the case of an OCSP response, the caller needs to parse the certs +// separately. +// +// Note that signatureAlgorithm is NOT parsed or validated. +// +// Certificate ::= SEQUENCE { +// tbsCertificate TBSCertificate, +// signatureAlgorithm AlgorithmIdentifier, +// signatureValue BIT STRING } +// +// BasicOCSPResponse ::= SEQUENCE { +// tbsResponseData ResponseData, +// signatureAlgorithm AlgorithmIdentifier, +// signature BIT STRING, +// certs [0] EXPLICIT SEQUENCE OF Certificate OPTIONAL } +Result SignedData(Reader& input, /*out*/ Reader& tbs, + /*out*/ SignedDataWithSignature& signedDataWithSignature); + +} } } // namespace mozilla::pkix::der + +#endif // mozilla_pkix_pkixder_h |