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- // Copyright 2013 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #ifndef COMPONENTS_NACL_LOADER_NACL_VALIDATION_QUERY_H_
- #define COMPONENTS_NACL_LOADER_NACL_VALIDATION_QUERY_H_
- #include <stddef.h>
- #include <string>
- #include "base/memory/raw_ptr.h"
- #include "base/strings/string_piece.h"
- #include "crypto/hmac.h"
- struct NaClValidationCache;
- class NaClValidationDB;
- class NaClValidationQuery;
- class NaClValidationQueryContext {
- public:
- NaClValidationQueryContext(NaClValidationDB* db,
- const std::string& profile_key,
- const std::string& nacl_version);
- NaClValidationQuery* CreateQuery();
- private:
- raw_ptr<NaClValidationDB> db_;
- // A key used by HMAC that is specific to this installation of Chrome.
- std::string profile_key_;
- // Bytes indicating the "version" of the validator being used. This is used
- // to implicitly invalidate the cache - changing the version will change the
- // hashes that are produced.
- std::string nacl_version_;
- };
- class NaClValidationQuery {
- public:
- // SHA256 digest size.
- static const size_t kDigestLength = 32;
- NaClValidationQuery(NaClValidationDB* db, const std::string& profile_key);
- NaClValidationQuery(const NaClValidationQuery&) = delete;
- NaClValidationQuery& operator=(const NaClValidationQuery&) = delete;
- void AddData(const char* data, size_t length);
- void AddData(const unsigned char* data, size_t length);
- void AddData(const base::StringPiece& data);
- int QueryKnownToValidate();
- void SetKnownToValidate();
- private:
- enum QueryState {
- READY,
- GET_CALLED,
- SET_CALLED
- };
- // The HMAC interface currently does not support incremental signing. To work
- // around this, each piece of data is signed and the signature is added to a
- // buffer. If there is not enough space in the buffer to accommodate new
- // data, the buffer contents are signed and the new signature replaces the
- // contents of the buffer. CompressBuffer performs this operation. In
- // affect, a hash tree is constructed to emulate incremental signing.
- void CompressBuffer();
- // Track the state of the query to detect suspicious method calls.
- QueryState state_;
- crypto::HMAC hasher_;
- raw_ptr<NaClValidationDB> db_;
- // The size of buffer_ is a somewhat arbitrary choice. It needs to be at
- // at least kDigestLength * 2, but it can be arbitrarily large. In practice
- // there are 4 calls to AddData (version, architechture, cpu features, and
- // code), so 4 times digest length means the buffer will not need to be
- // compressed as an intermediate step in the expected use cases.
- char buffer_[kDigestLength * 4];
- size_t buffer_length_;
- };
- // Create a validation cache interface for use by sel_ldr.
- struct NaClValidationCache* CreateValidationCache(
- NaClValidationDB* db, const std::string& profile_key,
- const std::string& nacl_version);
- #endif // COMPONENTS_NACL_LOADER_NACL_VALIDATION_QUERY_H_
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